BIOGEOCHEMICAL-CYCLE
1 of 1
TI: Bacterial contribution to sedimentary organic matter: A comparative study of lipid moieties in bacterial and Recent sediments.
AU: Goossens,-H.; Rijpstra,-W.I.C.; Duren,-R.R.; De-Leeuw,-J.W.; Schenck,-P.A.
SO: ORG.-GEOCHEM. 1986. vol. 10, no. 4-6, pp. 683-696
LA: English
ER: M (Marine)
AN: 1462297
1 of 313
TI: Comparison of the phytoplankton species composition and structure in the Climax Area (1973-1985) with that of Station ALOHA (1994)
AU: Venrick,-E.L.
AF: Mar. Life Res. Group, Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093-0227, USA
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 7, pp. 1643-1648
LA: English
ER: M (Marine)
AB: In August 1994, water samples were collected from seven depths on each of two casts at the Hawaiian Ocean Time-series station (ALOHA; 22 degree 45'N, 158 degree W). These samples allowed a comparison between the larger phytoplankton taxa at ALOHA and those in the Climax Area (near 28 degree N, 155 degree W) that were collected during summers between 1973 and 1985. Of the 142 species found at ALOHA, all but 6 have been seen in the Climax Area. The two-layered structure that is typical of the Climax Area was also found at station ALOHA, where the break between shallow and deep associations occurred between 100- and 135-m depth. However, abundances of the deep species at ALOHA were lower than in the Climax Area. The correlations between the rank order of abundances of phytoplankton from Sta. ALOHA and from the Climax Area fell within the spectrum of correlations between pairs of stations from the Climax Area. These results indicate that in August 1994 the phytoplankton at Sta. ALOHA was indistinguishable from that in the Climax Area between 1973 and 1985. Nevertheless, many additional studies are needed before results from the Climax Area or results from the Hawaiian Ocean Time-series program can be unconditionally generalized.
AN: 4364335
2 of 313
TI: Organic carbon isotope systematics of coastal marshes
AU: Middelburg,-J.J.; Nieuwenhuize,-J.; Lubberts,-R.K.; Van-de-Plassche,-O.
AF: Netherlands Inst. Ecol., Cent. for Estuarine and Coastal Ecol., Korringaweg 7, 4401 NT Yerseke, The Netherlands
SO: ESTUAR.-COAST.-SHELF-SCI. 1997 vol. 45, no. 5, pp. 681-687
LA: English
ER: M (Marine); B (Brackish)
AB: Measurements of nitrogen, organic carbon and delta super(13)C are presented for Spartina-dominated marsh sediments from a mineral marsh in SW Netherlands and from a peaty marsh in Massachusetts, U.S.A. delta super(13) C of organic carbon in the peaty marsh sediments is similar to that of Spartina material, whereas that in mineral marshes is depleted by 9-12 ppt. It is argued that this depletion in delta super(13)C of organic matter in marsh sediments is due to trapping of allochthonous organic matter which is depleted in super(13)C. The isotopic composition and concentration of organic carbon are used in a simple mass balance to constrain the amount of plant material accumulating in marsh sediments, i.e. in terms of the so-called net ecosystem production. Net ecosystem production ( similar to 2-100 g C/m super(2) year) is a small fraction (1-5%) of plant production ( similar to 2000 g C/m super(2)/year). This small amount of plant material being preserved is nevertheless sufficient to support marsh-accretion rates similar to the rate of sea-level rise.
AN: 4353774
3 of 313
TI: Conclusions to special issue: water quality and biology of United Kingdom rivers entering the North Sea: the Land Ocean Interaction Study (LOIS) and associated work
AU: Neal,-C.; House,-W.A.; Whitton,-B.A.; Leeks,-G.J.L.
AF: Institute of Hydrology, Maclean Building, Crowmarsh Gifford, Wallingford, Oxon OX10 8BB, UK
SO: Sci.-Total-Environ. 1998 vol. 210-211, no. 1-6, pp. 585-594
NT: Special issue: Land Ocean Interaction Study (LOIS).
LA: English
AB: This volume deals with the extensive information collected as part of one of the most ambitious environmental research programmes ever undertaken in the United Kingdom: the Land Ocean Interaction Study (LOIS). It concerns the water quality and biology of major British rivers draining into the North Sea and presents the newer findings in the context of an earlier special volume which dealt with the first 2 years of LOIS riverine research. The findings of the recently completed field programme at the core of the research is enhanced by specialist contributions on the key processes determining water quality and biological functioning within the LOIS rivers. The combination of an effective large-scale approach with standardised but comprehensive and high quality monitoring, highly structured databases and a full commitment to integrated research at all scales and across all the relevant disciplines, has led to new insights into how the riverine environment functions as an open system linked to atmospheric and marine processes and fluxes. The LOIS provides a valuable template for future national and international approaches to pollutant impacts on river systems, the shelf edge and the open ocean as well as a way forward for integrated environmental research approach in the United Kingdom and other developed as well as developing countries.
AN: 4342341
4 of 313
TI: Simulating carbon flux to the estuary: The first step
AU: Eatherall,-A.; Naden,-P.S.; Cooper,-D.M.
AF: Institute of Hydrology, Crowmarsh Gifford, Wallingford, Oxon OX10 6BB, UK
SO: Sci.-Total-Environ. 1998 vol. 210-211, no. 1-6, pp. 519-533
NT: Special issue: Land Ocean Interaction Study (LOIS).
LA: English
AB: The sources and sinks (point and non-point) of dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) are identified for the purposes of simulating carbon flux to the estuary. The sources and sinks are separated into three categories: allochthonous; anthropogenic; and autochthonous with each category examined in turn. Carbon loads to the Humber estuary are calculated and a mass balance calculation is performed for a section of the River Swale in Yorkshire showing decomposition rates of similar to 3.8 t C/ha/year and a flux of similar to 161 kt C/year. Finally, initial non-point source models are presented for DOC, POC and DIC. These algorithms are incorporated into a hydrological model that is used within the LOIS programme to simulate the flux of carbon to the river.
AN: 4342337
5 of 313
TI: Anomalies in coral reef community metabolism and their potential importance in the reef CO sub(2) source-sink debate
AU: Chisholm,-J.R.M.; Barnes,-D.J.
AF: Australian Institute of Marine Science, Private Mail Bag No. 3, Mail Centre, Townsville, Queensland 4810, Australia
SO: Proc.-Natl.-Acad.-Sci.-USA 1998 vol. 95, no. 11, pp. 6566-6569
LA: English
AB: It is not certain whether coral reefs are sources of or sinks for atmospheric CO sub(2). Air-sea exchange of CO sub(2) over reefs has been measured directly and inferred from changes in the seawater carbonate equilibrium. Such measurements have provided conflicting results. We provide community metabolic data that indicate that large changes in CO sub(2) concentration can occur in coral reef waters via biogeochemical processes not directly associated with photosynthesis, respiration, calcification, and CaCO sub(3) dissolution. These processes can significantly distort estimates of reef calcification and net productivity and obscure the contribution of coral reefs to global air-sea exchange of CO sub(2). They may, nonetheless, explain apparent anomalies in the metabolic performance of reefs close to land and reconcile the differing experimental findings that have given rise to the CO sub(2) debate.
AN: 4318417
6 of 313
TI: A synoptic study of nutrients in the north-west Irish Sea
AU: Gibson,-C.E.; Stewart,-B.M.; Gowen,-R.J.
AF: Agric. and Environ. Sci. Div., Dep. Agric. for Northern Ireland, Newforge Lane, Belfast BT9 5PX, Northern Ireland, UK
SO: ESTUAR.-COAST.-SHELF-SCI. 1997 vol. 45, no. 1, pp. 27-38
LA: English
ER: M (Marine)
AB: Concentrations of nitrate and nitrite (N), phosphorus (P) and silica (Si) were measured at a grid of stations in the north-west Irish Sea throughout 1992. The data were treated synoptically by mapping and graphical analysis to integrate data from 28 different stations. In spring, there was concurrent depletion of N, Si and P in the molar ratio 9 times 5:6 times 4:1, indicating that N was depleted before P and Si. Areal integrals were calculated for N and P at each station, which ranged in depth between 15 and 150 m. Over the summer, P integrals reduced pro rata with depth up to 60 m, but in stations deeper than 60 m, there was no further reduction in P. In contrast the areal N integral decreased in proportion to depth even in the deepest stations. It is suggested that loss of N in the deepwater stations may be due to denitrification in the bosom water. Over the winter N, P and Si concentrations returned to the winter maximum in more or less constant proportions. Mechanisms for the control of the nitrate concentration are discussed. A desk budget suggests that in situ regeneration of nitrate is the dominant process.
AN: 4353833
7 of 313
TI: The use of amides and other organic nitrogen sources by the phytoplankton Emiliania huxleyi
AU: Palenik,-B.; Henson,-S.E.
AF: Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0202, USA
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 7, pp. 1544-1551
LA: English
ER: M (Marine)
AB: Although dissolved organic nitrogen (DON) is beginning to be seen as a potentially important nitrogen source for phytoplankton, much remains to be learned about its components and their utilization. Emiliania huxleyi, a cosmopolitan eukaryotic phytoplankton species abundant in oligotrophic oceans and during blooms in some coastal regions, was screened for use of various DON compounds. Hypoxanthine and other purines support the nickel-dependent growth of most E. huxleyi strains. Acetamide and formamide but not longer chain aliphatic amides were found to be excellent nitrogen sources for growth; other phytoplankton were also found to utilize acetamide but not formamide. In E. huxleyi, small amides are transported into the cell followed by degradation to ammonia, possibly by amide-specific enzymes. The related molecules hydroxyurea and thiourea were toxic to the cells and caused an increase in fluorescence consistent with blockage of photosystem II. This fluorescence increase was inhibited by urea and acetamide, suggesting transport of hydroxyurea, thiourea, urea, and acetamide by the same or closely related transporters.
AN: 4342604
8 of 313
TI: Nutrient biogeochemistry of the coastal zone
AU: Jickells,-T.D.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: Science-Wash. 1998 vol. 281, no. 5374, pp. 217-222
LA: English
ER: M (Marine)
AB: The coastal seas are one of the most valuable and vulnerable of Earth's habitats. Significant inputs of nutrients to the coastal zone arrive via rivers, groundwater, and the atmosphere. Nutrient fluxes through these routes have been increased by human activity. In addition, the N:P:Si ratios of these inputs have been perturbed, and many coastal management practices exacerbate these perturbations. There is evidence of impacts arising from these changes (in phytoplankton numbers and relative species abundance, and deep-water oxygen declines) in areas of restricted water exchange. Elsewhere, the nutrient fluxes through the coastal zone appear to be still dominated by large inputs from the open ocean, and there is little evidence of anthropogenic perturbations.
AN: 4340262
9 of 313
TI: Biogeochemical controls and feedbacks on ocean primary production
AU: Falkowski,-P.G.; Barber,-R.T.; Smetacek,-V.
AF: Inst. Mar. and Coast. Sci., Rutgers Univ., New Brunswick, NJ 08901-8521, USA
SO: Science-Wash. 1998 vol. 281, no. 5374, pp. 200-206
LA: English
ER: M (Marine)
AB: Changes in oceanic primary production, linked to changes in the network of global biogeochemical cycles, have profoundly influenced the geochemistry of Earth for over 3 billion years. In the contemporary ocean, photosynthetic carbon fixation by marine phytoplankton leads to formation of similar to 45 gigatons of organic carbon per annum, of which 16 gigatons are exported to the ocean interior. Changes in the magnitude of total and export production can strongly influence atmospheric CO sub(2) levels (and hence climate) on geological time scales, as well as set upper bounds for sustainable fisheries harvest. The two fluxes are critically dependent on gephysical processes that determine mixed-layer depth, nutrient fluxes to and within the ocean, and food-web structure. Because the average turnover time of phytoplankton carbon in the ocean is on the order of a week or less, total and export production are extremely sensitive to external forcing and consequently are seldom in steady state. Elucidating the biogeochemical controls and feedbacks on primary production is essential to understanding how oceanic biota responded to and affected natural climatic variability in the geological past, and will respond to anthropogenically influenced changes in coming decades. One of the most crucial feedbacks results from changes in radiative forcing on the hydrological cycle, which influences the aeolian iron flux and, in turn, affects nitrogen fixation and primary production in the oceans.
AN: 4340259
10 of 313
TI: Quantifying fluid flow, solute mixing, and biogeochemical turnover at cold vents of the eastern Aleutian subduction zone
AU: Wallmann,-K.; Linke,-P.; Suess,-E.; Bohrmann,-G.; Sahling,-H.; Schlueter,-M.; Daahlmann,-A.; Lammers,-S.; Greinert,-J.; Von-Mirbach,-N.
AF: GEOMAR Res. Cent., Wischhofstr. 1-3, D-24148 Kiel, Germany
SO: GEOCHIM.-COSMOCHIM.-ACTA 1997 vol. 61, no. 24, pp. 5209-5219
LA: English
ER: M (Marine)
AB: In situ oxygen fluxes were measured at vent sites in the Aleutian Trench at a water depth of almost 5000 m using a TV-guided benthic flux chamber. The flux was 2 orders of magnitude greater than benthic oxygen fluxes in areas unaffected by venting on the continental margin off Alaska. Porewater profiles taken from the surface sediment below a vent site showed high concentrations of sulfide, methane, and ammonia. The reduced carbon and nitrogen compounds are transported to the vent site by fluids expelled from deeper anoxic sediment layers by the forces of plate convergence. The tectonically driven fluid flow was determined from the biochemical turnover in vent communities and was found to be 3.4 plus or minus 0.5 m/yr. A model was used to quantify the transport of silica, Ca super(2+), and sulfate via diffusion, advection, and bioirrigation through the surface sediments of a vent site. A nonlocal mixing coefficient of 20-30/yr was determined by fitting the model curves to the measured porewater profiles showing that the transport of solutes within the near-surface sediments and across the sediment-water interface is dominated by the activity of the vent fauna. Sulfate-containing oceanic bottom water and methane-rich vent fluids were mixed below the clam colony to produce sulfide and a CaCO sub(3) precipitate. The vent biota shape their immediate environment and control the sediment-water exchange and the benthic fluxes at vent sites. The oxygen consumption at vent sites is a major sink for oxygen at the study area.
AN: 4340114
11 of 313
TI: Ecology of southeastern salt marshes
AU: Vernberg,-F.J.
AF: Belle W. Baruch Inst. for Mar. Biol. and Coastal Res., Univ. South Carolina, Columbia, SC 29208, USA
CO: Sustainable Development in the Southeastern Coastal Zone Symp., Myrtle Beach, SC (USA), 2-5 Mar 1993
SO: SUSTAINABLE-DEVELOPMENT-IN-THE-SOUTHEASTERN-COASTAL-ZONE. Vernberg,-F.J.;Vernberg,-W.B.;Siewicki,-T.-eds. SC-USA UNIVERSITY-OF-SOUTH-CAROLINA-PRESS 1996 no. 20 pp. 117-133
ST: BELLE-W.-BARUCH-LIBR.-MAR.-SCI. no. 20
LA: English
ER: M (Marine); B (Brackish)
AB: Saltwater marshes are a dominant feature of the southeastern coastal landscape. Not only is the areal extent of these marshes great, but they play a significant role in the ecology of estuaries and coastal waters. Due to the dominant vascular plant, Spartina, and the attendant other plants, salt marshes are one of the most productive habitats in the world. Associated with the richness and abundance of food found in marsh-estuarine system are the many animal species utilize this system on either a temporary or permanent basis. About 90% of the commercial fishery landings in the Southeast include species that spend a portion of their life cycle in estuaries. Salt marshes are exposed to marked fluctuations in biotic and abiotic factors since they are exposed alternately to aerial and aquatic conditions depending upon such factors as tides, winds, and rainfall. The biotic structure of this habitat fluctuates and represents a complex series of food webs and biogeochemical cycles.
AN: 4340049
12 of 313
TI: Influence of mesoscale eddies on new production in the Sargasso Sea
AU: McGillicuddy,-D.J.,Jr.; Robinson,-A.R.; Siegel,-D.A.; Jannasch,-H.W.; Johnson,-R.; Dickey,-T.D.; McNeil,-J.; Michaels,-A.F.; Knap,-A.H.
AF: Dep. Applied Ocean Phys. and Eng., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: Nature 1998 vol. 394, no. 6690, pp. 263-266
LA: English
ER: M (Marine)
AB: It is problematic that geochemical estimates of new production--that fraction of total primary production in surface waters fuelled by externally supplied nutrients--in oligotrophic waters of the open ocean surpass that which can be sustained by the traditionally accepted mechanisms of nutrient supply. In the case of the Sargasso Sea, for example, these mechanisms account for less than half of the annual nutrient requirement indicated by new production estimates based on three independent transient-tracer techniques. Specifically, approximately one-quarter to one-third of the annual nutrient requirement can be supplied by entrainment into the mixed layer during wintertime convection, with minor contributions from mixing in the thermocline and wind-driven transport (the potentially important role of nitrogen fixation--for which estimates vary by an order of magnitude in this region--is excluded from this budget). Here we present four lines of evidence--eddy-resolving model simulations, high-resolution observations from moored instrumentation, shipboard surveys and satellite data--which suggest that the vertical flux of nutrients induced by the dynamics of mesoscale eddies is sufficient to balance the nutrient budget in the Sargasso Sea.
AN: 4338953
13 of 313
TI: [Study of decomposition of marine macrophytes]
OT: Estudio de descomposicion de macrofitos marinos
AU: Granado-Reyes,-I.; Caballero-Ortega,-P.
AF: Dpto. Biologia, Facultad Ciencias del Mar, ULPGC, Las Palmas de Gran Canaria, Canary Islands, Spain
CA: Instituto Canario de Ciencias Marinas, Las Palmas de Gran Canaria (Spain)
CO: 1. Congreso sobre Oceanografia y Recursos Marinos en el Atlantico Centro-Oriental, Gran Canaria (Spain), 28-30 Nov 1990
SO: Oceanography-and-marine-resources-in-the-eastern-Central-Atlantic.-OCEANOGRAFIA-Y-RECURSOS-MARINOS-EN-EL-ATLANTICO-CENTRO-ORIENTAL Llinas,-O.;Gonzalez,-J.A.;Rueda,-M.J.-eds. Las-Palmas-de-Gran-Canaria-Spain ICCM 1996 pp. 143-154
LA: Spanish
ER: M (Marine)
AB: Marine macrophyte litter degrades through a rapid leaching phase, a second phase in which decomposers degrade the litter, and a third very slow phase during which refractory compounds remain or are formed. The chemical composition of the litter is the major factor controlling the decay rates during the phases of decomposition. In order to investigate the decomposition rate, the leaching of soluble components and the chemical changes in the decomposing tissue of marine macrophytes, laboratory incubations were performed of 3 seaweeds (Enteromorpha compressa, Fucus spiralis, Gelidium canariensis) and a seagrass (Cymnodocea nodosa), under aerobic conditions.
AN: 4334026
14 of 313
TI: Release and bioavailability of C, N, P, Se, and Fe following viral lysis of a marine chrysophyte
AU: Gobler,-C.J.; Hutchins,-D.A.; Fisher,-N.S.; Cosper,-E.M.; Sanudo-Wilhelmy,-S.A.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11794-5000, USA
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 7, pp. 1492-1504
LA: English
ER: M (Marine)
AB: The potential importance of the viral lysis of phytoplankton for nutrient and carbon cycling has been acknowledged, but no quantitative assessments of this phenomenon exist. Radiotracer experiments examined the release and bioavailability of C, N, P, Fe, and Se following viral lysis of the "brown tide" chrysophyte Aureococcus anophagefferens. Photochemical effects on the dissolved-particulate partitioning and biological uptake of virally released elements were also investigated. Viral lysis of A. anophagefferens released 50% more C and Se than uninfected control cells to the dissolved phase, while N, P, and Fe remained in the particulate phase. There was a significant inverse correlation between A. anophagefferens and bacterial densities, as well as an increase in particulate organic nitrogen levels in cultures during viral lysis. These observations indicate that released dissolved organic matter supported bacterial growth and may be a pathway by which various elements are diverted in microbial food webs. Dissolved nutrients released by viral lysis were accumulated to varying degrees by natural assemblages of marine bacteria and cultured diatoms, and virally regenerated N and P relieved diatom nutrient limitation. During a 4-wk incubation, 80% of C and P within cell lysis debris was released to the dissolved phase, likely due to bacterial activity. Photochemical degradation of cell lysis debris enhanced dissolved levels of Se (100%) and Fe (50%) and reduced total dissolved C by 15%. Photochemistry doubled the bioavailability of virally released Se to diatoms, while decreasing the bioavailability of C to bacteria threefold. The viral lysis of an A. anophagefferens bloom in the field could release 40 mu M dissolved organic carbon and rapidly transfer other released elements to bacteria. Such occurrences may significantly affect water column chemistry, species composition, and succession within marine plankton communities.
AN: 4337203
15 of 313
TI: Mahoney Lake: A case study of the ecological significance of phototrophic sulfur bacteria
AU: Overmann,-J.
AF: Inst. fuer Chemie und Biologie des Meeres, Univ. Oldenburg, D-26111 Oldenburg, Germany
SO: ADV.-MICROB.-ECOL. 1997 vol. 15, pp. 251-284
LA: English
ER: F (Freshwater)
AN: 4337182
16 of 313
TI: Seasonal changes in the biochemistry of lake seston
AU: Kreeger,-D.A.; Goulden,-C.E.; Kilham,-S.S.; Lynn,-S.G.; Datta,-S.; Interlandi,-S.J.
AF: Patrick Center for Environmental Research, Academy of Natural Sciences, 19th and The Parkway, Philadelphia, PA 19103, USA
SO: Freshwat.-Biol. 1997 vol. 38, no. 3, pp. 539-554
NT: Special issue: The role of food quality for zooplankton. (Proceedings of a PEG workshop held at Nieuwersluis, the Netherlands, 17-21 March 1996).
LA: English
ER: F (Freshwater)
AB: The quantity of seston was measured and the elemental carbon, nitrogen and phosphorus (C, N, P) and biochemical composition (carbohydrates, proteins, lipids) of the <53 mu m size fraction in three temperate lakes, (lakes Giles, Lacawac and Waynewood), during one year were analysed. The lakes were characterized as oligotrophic, mesotrophic and eutrophic. Linear regression analyses defined associations between seston composition and either lake trophic status, depth or season. Concentrations of seston C, N and P were high in most cases in the spring and autumn and low in summer. Concentrations of P were particularly high during late summer and early autumn in the metalimnion, perhaps because of recovery of P from anaerobic sediments and hypolimnetic waters. Concentrations of protein, carbohydrate, polar lipid and triglyceride generally increased with lake type as expected (greatest in the eutrophic lake). As the year progressed, the concentration of polar lipid decreased. The biochemical composition of seston varied during the year and among lakes; for example, in Lake Waynewood the proportion of protein composing the seston (% protein by weight) varied from <10% to >40%. These seasonal biochemical changes in the seston food base were compared with biochemical changes known to occur in algae grown under N- or P-limited conditions in the laboratory, and the resultant quality of this algal food for suspension-feeding consumers (zooplankton). It was concluded that zooplankton were likely to be physiologically challenged by these distinct seasonal shifts in the quality of lake seston.
AN: 4334402
17 of 313
TI: Roles of submicron particles and colloids in microbial food webs and biogeochemical cycles within marine environments
AU: Nagata,-T.; Kirchman,-D.L.
AF: Ocean Res. Inst., Univ. Tokyo, Nakano, Tokyo 164, Japan
SO: ADV.-MICROB.-ECOL. 1997 vol. 15, pp. 81-103
LA: English
ER: M (Marine)
AB: This chapter presents recently emerging ideas on interactions of colloids and microorganisms and their implications for trophic dynamics and biogeochemical cycles in aquatic environments. We will emphasize interdisciplinary interactions between microbiology and geochemistry, where new perspectives are rapidly growing. Some challenging areas of future studies are also discussed.
AN: 4332607
18 of 313
TI: Geochemical constraints on chemolithoautotrophic metabolism by microorganisms in seafloor hydrothermal systems
AU: McCollom,-T.M.; Shock,-E.L.
AF: MS 4, Woods Hole Oceanographic Inst., Woods Hole, MA 02543, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1997 vol. 61, no. 20, pp. 4375-4391
LA: English
ER: M (Marine)
AB: Mixing of hydrothermal fluids and seawater at the ocean floor, combined with slow reaction kinetics for oxidation/reduction reactions, provides a source of metabolic energy for chemolithotrophic microorganisms which are the primary biomass producers for an extensive submarine ecosystem that is essentially independent of photosynthesis. Thermodynamic models are used to explore geochemical constraints on the amount of metabolic energy potentially available from chemosynthetic reactions involving S, C, Fe, and Mn compounds during mixing of hydrothermal fluids with seawater. For the vent fluid used in the calculations (EPR 21 degree N OBS), the model indicates that mixing environments are favorable for oxidation of H sub(2)S, CH sub(4), Fe super(2+) and Mn super(2+) only below similar to 38 degree C, with methanogenesis and reduction of sulfate or S degree favored at higher temperatures, suggesting that environments dominated by mixing provide habitats for mesophilic (but not thermophilic) aerobes and thermophilic (but not mesophilic) anaerobes. A maximum of similar to 760 cal per kilogram vent fluid is available from sulfide oxidation while between 8 and 35 cal/kg vent fluid is available from methanotrophy, methanogenesis, oxidation of Fe or Mn, or sulfate reduction. The total potential for chemosynthetic primary production at deep-sea hydrothermal vents globally is estimated to be about 10 super(13) g biomass per year, which represents similar to 0.02% of the global primary production by photosynthesis in the oceans. Thermophilic methanogens and sulfate- and S degree -reducers are likely to be the predominant organisms in the walls of vent chimneys and in the diffuse mixing zones beneath warm vents, where biological processes may contribute to the high methane concentrations of vent fluids and heavy super(34)S/ super(32)S ratios of vent sulfide minerals. The metabolic processes taking place in these systems may be analogs of the first living systems to evolve on the Earth.
AN: 4332573
19 of 313
TI: Nitrogen elimination in two deep eutrophic lakes
AU: Mengis,-M.; Gaechter,-R.; Wehrli,-B.; Barnasconi,-S.
AF: Swiss Federal Inst. for Environ. Sci. and Technol. (EAWAG), Limnological Res. Cent., CH-6047 Kastanienbaum, Switzerland
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 7, pp. 1530-1543
LA: English
ER: F (Freshwater)
AB: Nitrogen elimination was investigated in two eutrophic Swiss lakes with different hypolimnetic oxygen conditions. Nitrogen burial was estimated from sediment-trap and sediment-core studies. Denitrification and NO sub(3) super(-)-ammonification rates were quantified with super(15)NO sub(3) super(-) and acetylene incubation experiments and whole-lake mass balances. The study confirmed earlier reports that the acetylene-block technique yields denitrification rates that are systematically too low. Denitrification rates obtained from isotope tracer experiments were compatible with nitrogen consumption rates observed in flux chamber experiments and whole-lake mass balances. The NO sub(3) super(-)-ammonification contributed <5% to the NO sub(3) super(-) consumption rate in Lake Baldegg. Coupled nitrification-denitrification seemed to be insignificant at the deepest station of Lake Baldegg. The comparison of in situ denitrification rates measured at the deepest site (4.3 mmol m super(-2) d super(-1)) with the denitrification rate obtained from whole-lake mass balances (6.1 mmol m super(-2) d super(-1)) indicates that enhanced denitrification may be present in shallower sediments with a better supply of O sub(2). Mass transfer coefficients for NO sub(3) super(-) were similar in both lakes (21.7 and 21.4 m yr super(-1)). The NO sub(3) super(-) concentration seems to be a key parameter in determining denitrification rates.
AN: 4331990
20 of 313
TI: Iron-limited diatom growth and Si:N uptake ratios in a coastal upwelling regime
AU: Hutchins,-D.A.; Bruland,-K.W.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: Nature 1998 vol. 393, no. 6685, pp. 561-564
LA: English
ER: M (Marine)
AB: There is compelling evidence that phytoplankton growth is limited by iron availability in the subarctic Pacific, and equatorial Pacific and Southern oceans. A lack of iron prevents the complete biological utilization of the ambient nitrate and influences phytoplankton species composition in these open-ocean "high-nitrate, low-chlorophyll" (HNLC) regimes. But the effects of iron availability on coastal primary productivity and nutrient biogeochemistry are unknown. Here we present the results of shipboard seawater incubation experiments which demonstrate that phytoplankton are iron-limited in parts of the California coastal upwelling region. As in offshore HNLC regimes, the addition of iron to these nearshore HNLC waters promotes blooms of large chain-forming diatoms. The silicic acid:nitrate (Si:N) uptake ratios in control incubations are two to three times higher than those in iron incubations. Diatoms stressed by a lack of iron should therefore deplete surface waters of silicic acid before nitrate, leading to a secondary silicic acid limitation of the phytoplankton community. Higher Si:cell, Si:C and Si:pigment ratios in diatoms in the control incubations suggest that iron limitation leads to more silicited, faster-sinking diatom biomass. These results raise fundamental questions about the nature of nutrient-limitation interactions in marine ecosystems, paleoproductivity estimates based on the sedimentary accumulation of biogenic opal, and the controls on carbon export from some of the world's most productive surface waters.
AN: 4327200
21 of 313
TI: A modelling study of ecosystem dynamics and nutrient cycling in the Humber Plume, UK
AU: Allen,-J.I.
AF: Plymouth Mar. Lab., Prospect Place, West Hoe, Plymouth PL1 3DH, UK
SO: J.-SEA-RES. 1997 vol. 38, no. 3-4, pp. 333-359
NT: Special Issue: European Regional Seas Ecosystem Model II.
LA: English
ER: M (Marine)
AB: The European Regional Seas Ecosystem Model (ERSEM) has been coupled with a two-dimensional depth-averaged transport model of the Humber plume region and run to simulate 1988-1989. Simulations of the spatial and temporal variations in chlorophyll-a, nitrate, phosphate and suspended particulate matter distributions in winter, spring and summer show how the development of the spring bloom and subsequent maintenance of primary production is controlled by the physicochemical environment of the plume zone. Results are also shown for two stations, one characterised by the high nutrient and suspended matter concentrations of the plume and the other by the relatively low nutrient and sediment concentrations of the offshore waters. The modelled net primary production at the plume site was 105 g C/m super(2)/a and 127 g C/m super(2)/a offshore. Primary, production was controlled by light limitation between October and March and by the availability of nutrients during the rest of the year. The phytoplankton nutrient demand is met by in-situ recycling processes during the summer. The likely effect of increasing and decreasing anthropogenic riverine inputs of nitrate and phosphate upon ecosystem function was also investigated. Modelling experiments indicate that increasing the nitrogen to silicate ratio in freshwater inputs increased the production of non-siliceous phytoplankton in the plume. The results of this model have been used to calculate the annual and quarterly mass balances describing the usage of inorganic nitrogen, phosphate and silicate within the plume zone for the period of the NERC North Sea survey (September 1988 to October 1989). The modelled Humber plume retains 3.9% of the freshwater dissolved inorganic nitrogen, 2.2% of the freshwater phosphate and 1.3% of the freshwater silicate input over the simulated seasonal cycle. The remainder is transported into the southern North Sea in either dissolved or particulate form. The reliability of these results is discussed.
AN: 4321469
22 of 313
TI: Predictive models for phosphorus retention in wetlands
AU: Richardson,-C.J.; Qian,-S.; Craft,-C.B.; Qualls,-R.G.
AF: Duke Univ. Wetland Cent., Nicholas Sch. Environ., Durham, NC 27708, USA
CO: International Workshop "Nutrient Cycling and Retention in Wetlands and Their Use in Wastewater Treatment", Trebon (Czech Rep.), 5-9 Sep 1995
SO: WETLANDS-ECOL.-MANAGE. 1997 vol. 4, no. 3, pp. 159-175
LA: English
AB: The potential of wetlands to efficiently remove (i.e., act as a nutrient sink) or to transform nutrients like phosphorus under high nutrient loading has resulted in their consideration as a cost-effective means of treating wastewater on the landscape. Few predictive models exist which can accurately assess P retention capacity. An analysis of the north American data base (NADB) allowed us to develop a mass loading model that can be used to predict P storage and effluent concentrations from wetlands. Phosphorus storage in wetlands is proportional to P loadings but the output total phosphorus (TP) concentrations increase exponentially after a P loading threshold is reached. The threshold P assimilative capacity based on the NADB and a test site in the Everglades is approximately 1 g m super(-2) yr super(-1). We hypothesize that once loadings exceed 1 g m super(-2) yr super(-1) and short-term mechanisms are saturated, that the mechanisms controlling the uptake and storage of P in wetlands are exceeded and effluent concentrations of TP rise exponentially. We propose a "One Gram Rule" for freshwater wetlands and contend that this loading is near the assimilative capacity of wetlands. Our analysis further suggests that P loadings must be reduced to 1 g m super(-2) yr super(-1) or lower within the wetland if maintaining long-term low P output concentrations from the wetlands is the central goal.
AN: 4314866
23 of 313
TI: Colloid/solution partitioning of metal-selective organic ligands, and its relevance to Cu, Pb and Cd cycling in the Firth of Clyde
AU: Muller,-F.L.L.
AF: Department of Chemistry, University of Bergen, Allegaten 41, 5007 Bergen, Norway
SO: Estuar.-Coast.-Shelf-Sci. 1998 vol. 46, no. 3, pp. 419-437
LA: English
AB: The electrochemical lability of Cu, Pb and Cd and the complexation parameters (stability constants, ligand concentrations) of their organic ligands were determined by anodic stripping voltammetry (ASV) in 14 samples collected in April-May 1994 from the lower Clyde Estuary (S<30.0), through the surface estuarine plume (30.0<S<32.4), and into the Clyde Sea. The titrations were applied to 0.4 mu m-filtered and cross-flow filtered ( similar to 1 nm cut-off) fractions of each sample. In addition, the surface electrical properties of the colloidal matter (1 nm<size<0.4 mu m) were examined in 0.01 M NaCl medium as a function of pH by dynamic light scattering (DLS) electrophoresis. Copper was carried to the Clyde Sea by the plume largely in a dissolved form but subsequently reacted with - or formed - colloids. These colloids were either of marine origin or built up in situ from smaller sub-units such as organic macromolecules originating from the sediments. Overall, the degree of organic complexation for Cu (typically 76-96%) was less than that reported in other inshore marine systems. Biological production of strong ligands did take place in an adjoining loch, but their control on Cu speciation (up to 99.99% Cu in inert forms) remained localized. By contrast, organic complexation was sufficient to maintain pPb (pPb = - log [Pb super(2+)]) as high as 11.7-12.5. Lead in river runoff was extensively and strongly bound to organics. A unique class of ligands of in situ origin and belonging to the colloidal phase was detected at 40 m depth, i.e. under the plume. This colloidal material had limited affinity for Cd and no detectable affinity for Cu, and probably consisted of the remains of micro-organisms which must have been concentrated at this depth by the plume circulation. Despite some affinity for the above-mentioned colloidal ligands (resulting in 54-88% complexation) and for the dissolved ligands produced by phytoplankton (59-64% complexation), Cd was generally poorly bound (0-30% complexation) and the ligands responsible were mostly of marine origin. Although a fraction of the particulate Pb (associated with Mn-rich particles) was removed from the surface plume by sedimentation, the major modification in the seaward flux seemed to occur at the leading edge of the plume. There was a change in the speciation of Pb across this frontal zone, from a dominance by colloids and macroparticles in the plume to a situation where most of Pb found in the 0.4 mu m-filtered fraction was also present in the <1 nm permeate. In contrast, Cu became less extensively associated with the dissolved phase away from the plume. When interpreted in combination, the ASV and DLS results show that two bulk properties of organic coatings on colloids (electrophoretic mobility and second acidity constant), important in the context of colloid stability, can explain some of the variability in the colloid-solution partitioning of metal-complexing ligands. What is more, the surface electrical state of the colloids appears to have a different effect on the adsorption of Pb-binding ligands than on that of Cu-binding ligands, supporting the conclusion reached from the spatial distribution of ligands that they are metal-selective.
AN: 4308463
24 of 313
TI: Geoacoustic and physical properties of carbonate sediments of the Lower Florida Keys
AU: Richardson,-M.D.; Lavoie,-D.L.; Briggs,-K.B.
AF: Marine Geosciences Division, Naval Research Laboratory, Stennis Space Center, MS 39529-5004, USA
SO: Geo-Mar.-Lett. 1997 vol. 17, no. 4, pp. 316-324
NT: Special issue: Benthic boundary layer processes in the Lower Florida Keys.
LA: English
AB: Near-surface sediment geoacoustic and physical properties were measured from a variety of unconsolidated carbonate sediments in the Lower Florida Keys. Surficial values of compressional and shear speed correlate with sediment physical properties and near-surface acoustic reflectivity. Highest speeds (shear 125-150 m s super(-1); compressional 1670-1725 m s super(-1)) are from sandy sediments near Rebecca Shoal and lowest speeds (shear 40-65 m s super(-1); compressional 1520-1570 m s super(-1)) are found in soft, silty sediments which collect in sediment ponds in the Southeast Channel of the Dry Tortugas. High compressional wave attenuation is attributed to scattering of acoustic waves from heterogeneity caused by accumulation of abundant shell material and other impedance discontinuities rather than high intrinsic attenuation. Compared to siliciclastic sediments, carbonate sediment shear wave speed is high for comparable values of sediment physical properties. Sediment fabric, rather than changes due to the effects of biogeochemical processes, is responsible for these differences.
AN: 4269892
25 of 313
TI: Diffusion and reactions in the vicinity of plankton: A refined model for inorganic carbon transport
AU: Wolf-Gladrow,-D.; Riebesell,-U.
AF: Alfred-Wegener-Institute for Polar and Marine Research, Postfach 120161, D-27515 Bremerhaven, Germany
SO: MAR.-CHEM. 1997 vol. 59, no. 1-2, pp. 17-34
LA: English
ER: m
AB: Inorganic carbon uptake by phytoplankton depletes the immediate cell environment and disturbs the carbonate system equilibrium. Uptake is balanced by both diffusional transport across and chemical reactions within the depleted boundary layer. In this study, we have derived a model that simulates inorganic carbon diffusion and reactions in the vicinity of phytoplankton cells. To allow a general application of the model, the reaction kinetics of the carbonate system are reviewed and temperature- and salinity-dependence of the various rate constants are discussed. A consistency condition for some of the kinetic rates is derived. The effective thickness of the diffusive boundary layer in spherical and planar geometry is discussed. In addition, the effect of cell shape on diffusive transport to phytoplankton is examined and a simple means to account for this effect in model calculations is presented. In a second step, the complete description of the diffusion-reaction system is simplified to consider two special cases in which (1) algal production relies on CO2(aq) as the single source of inorganic carbon, and (2) CO2, HCO3-, or CO32- are utilized independently for organic matter production combined with calcite precipitation. In the size range typical for phytoplankton cells model predictions of these simplified versions are nearly identical to those of the complete model, indicating that the simplified models represent good approximations of the complete diffusion-reaction system.
AN: 4212144
26 of 313
TI: Factors controlling trophic conditions in the north-west Adriatic basin: seasonal variability
AU: Giordani,-P.; Miserocchi,-S.; Balboni,-V.; Malaguti,-A.; Lorenzelli,-R.; Honsell,-G.; Poniz,-P.
AF: Istituto per la Geologia Marina, CNR - Via Gobetti 101, 40129 Bologna, Italy
SO: MAR.-CHEM. 1997 vol. 58, no. 3-4, pp. 351-360
LA: English
ER: m
AB: The North-Adriatic basin shows typical shallow water mass characteristics which in a first approach, can be considered independent of the Middle and the Southern basins, being more affected by seasonal temperature and salinity variability. Primary production estimates represent the main quantitative assessments of the trophic conditions of a marine system, resulting from the combined effect of a large number of oceanographic factors. In this paper the results from three EUROMARGE AS (EEC-MAST II-MTP project) field trips carried out in 1994 are presented as a contribution to the better understanding of the factors controlling the trophic balance in the Northern Adriatic basin. These results include: depth profiles of salinity, nutrients and chlorophyll a concentrations, oxygen saturation, phytoplankton taxonomy and abundance, estimated biomass and primary production measurements by the 14C in-situ incubation method. The field trips were carried out in three seasons (February, July, September 1994) and the results reported belong to three stations in the northern basin, 5 miles off Ravenna, Cesenatico and Ancona, respectively. As expected, the physical situation of the water column was different in the three periods: the water was mixed in February and stratified in July and September. Nutrient concentrations were higher in winter, whilst the maximum of primary production was measured in September. The phytoplankton was composed predominantly of diatoms. The correlations between primary production and salinity reflect a difference in the factors controlling primary production. During February and September nutrients coming from rivers play an important role, although with a decreasing influence from station 1, nearest to the Po delta, towards station 3. Depth profiles of nutrient concentrations and O2 saturation measured during summer in the water column suggest that regeneration of nutrients in the water column down to the bottom boundary layer must play an important role in the nutrient cycling and dynamics in the basin.
AN: 4212139
27 of 313
TI: The effects of river input on the ecosystem dynamics in the continental coastal zone of the North Sea using ERSEM
AU: Lenhart,-H.J.; Radach,-G.; Ruardij,-P.
AF: Inst. fuer Meereskunde der Univ. Hamburg, Troplowitzstrasse 7, D-22529 Hamburg, Germany
SO: J.-SEA-RES. 1997 vol. 38, no. 3-4, pp. 249-274
NT: Special Issue: European Regional Seas Ecosystem Model II.
LA: English
ER: M (Marine)
AB: The general characteristics of the continental coastal zone, with nutrient concentrations, primary production and biomass high near the coast but decreasing with distance from the coast, are simulated by a box-refined version of the ecosystem model ERSEM. Aggregated model results compared to the literature as well as to two different three-dimensional models show a good agreement in the coastal region. The dynamical interactions as simulated by the ecosystem model are presented in the form of N/P ratios, the limitation by various nutrients and changes in the pathways of the flow of matter in the boxes; e.g. while the silicate limitation stops the spring bloom offshore, near the coast it is terminated by zooplankton grazing. When the river load was reduced by 50%, the largest effect was observed in the coastal boxes with 15% reduction of the net primary production. The discharges of the major rivers hardly affect the central North Sea, but lead to significant changes in nutrient limitations and mass flows in the coastal area. The realistic forcing, which was adopted for this setup, allows a higher net primary production in the southern North Sea in 1989 than in 1988, even though the nutrient river loads in 1989 were lower. The reason appears to be a higher solar energy input in 1989, by about 10 W/m super(2)/d, compared to 1988.
AN: 4314956
28 of 313
TI: Climatological annual cycles of nutrients and chlorophyll in the North Sea
AU: Radach,-G.; Paetsch,-J.
AF: Inst. fuer Meereskunde der Univ. Hamburg, Troplowitzstrasse 7, D-22529 Hamburg, Germany
SO: J.-SEA-RES. 1997 vol. 38, no. 3-4, pp. 231-248
NT: Special Issue: European Regional Seas Ecosystem Model II.
LA: English
ER: M (Marine)
AB: A large amount of nutrient and chlorophyll data from the North Sea were compiled and organised in a research data base to produce annual cycles on a relatively fine spatial resolution of 1 degree in each horizontal direction. The data originate from many different sources and were partly provided by the ECOMOD data base of the Institut fuer Meereskunde in Hamburg and partly by ICES in Copenhagen to cover the time range from 1950 to 1994. While the annual cycles of nutrients and chlorophyll derived for the continental coastal zone are representative for the decade 1984-1993 only, those for the remaining parts of the North Sea may be considered climatological annual cycles based on data from more than four decades. The composite data set of climatological annual cycles of medians and their climatological ranges is well suited to serve for validational and forcing purposes for ecosystem models of the North Sea, which have a resolution larger than or equal to 1 degree in both longitude and latitude. The annual cycles of the macronutrients and chlorophyll presented here for 1 degree x 1 degree squares in the North Sea show especially that sufficient observational data exist to provide initial, forcing and validational data for the simulations with the 130-box setup (ND130) of the ecosystem model ERSEM. The annual cycles presented give a clear picture for the whole of the North Sea. The highest concentrations occur at the continental coasts as a result of continued river input, which is added to the ongoing atmospheric input over the North Sea. Also, from the Atlantic Ocean water with relatively high nutrient concentrations enters the North Sea via the northern boundary. In the productive areas on and around the Dogger Bank nutrient concentrations are lower than in the other parts of the North Sea, even in winter. The areas with seasonal stratification have very different annual cycles in the upper (0-30 m) and lower layers (30 m-bottom). The shallow boxes are fully mixed and exhibit a relatively fast increase of nutrient concentrations caused by summer regeneration of nutrients.
AN: 4314955
29 of 313
TI: An analysis of benthic biological dynamics in a North Sea ecosystem model
AU: Blackford,-J.C.
AF: Plymouth Mar. Lab., Prospect Place, West Hoe, Plymouth PL1 3DH, UK
SO: J.-SEA-RES. 1997 vol. 38, no. 3-4, pp. 213-230
NT: Special Issue: European Regional Seas Ecosystem Model II.
LA: English
ER: M (Marine)
AB: This paper presents an overview and analysis of the benthic biological submodel of the European Regional Seas Ecosystem Model II (ERSEM II). This submodel consists of a detailed model description of the benthic system which is integrated with a marine ecosystem model which attempts to address the full range of pelagic and benthic biogeochemical and physical processes. The submodel simulates the seasonal dynamics of a number of functional groups, ranging from decomposers to predators and their interaction with detrital matter in the sediments. The improvements and extensions to the benthic biology submodel compared with the previous published version of the European Regional Seas Ecosystem Model are described. The improvements comprise: the reformulation of turbation and irrigation as functions of faunal activity, the inclusion of oxygen stress limitations and mortalities, a refinement of the description of detritus, additions to the diet of the filter feeders in line with the extensions to the primary production module and an extensive re-parameterisation. Using the 1 degree x 1 degree North Sea application, the submodel predictions are compared with data and the performance of the submodel assessed. Using the results of the submodel, the relation between benthic biological dynamics and its principal determinants, depth and overlying production is examined. The model is found to give qualitatively correct results. The transition in community type from anaerobe/deposit feeder in the south to a more mixed community in the north, involving aerobes and meiobenthos is also correctly predicted by the model. The biology is demonstrated to have a strong influence on nutrient efflux. The lack of resuspension/deposition processes is identified as the most significant omission from the current model.
AN: 4314954
30 of 313
TI: Carbon sources and cycle in the western Mediterranean - the use of molecular markers to determine the origin of organic matter
AU: Bouloubassi,-I.; Lipiatou,-E.; Saliot,-A.; Tolosa,-I.; Bayona,-J.M.; Albaiges,-J.
AF: Departement de Geologie et Oceanographie, URA CNRS 197, Univ. de Bordeaux I Nouvelle, Ave. des Facultes, 33405 Talence, France
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 781-799
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: A series of molecular organic markers were determined in surface sediment samples collected in the Rhone and Ebro prodeltas and the western Mediterranean Basin in order to map and estimate the flux of naturally-derived organic matter inputs to the area. Continental and marine inputs were characterized by the distributions of n-alkanes, n-fatty acids, sterols, and polycyclic aromatic hydrocarbons (PAHs) such as retene, perylene and tetrahydrochrysenes ( capital sigma THC). The distribution of terrestrial markers evidenced the influence of rivers as main vectors of continentally-derived inputs in the area. In the data set of the Rhone delta and slope, including stations from the Gulf of Lions, significant correlations were observed between the organic content of sediment and the capital sigma THC and retene concentrations (R super(2) = 0.88 and 0.68, respectively) and between capital sigma THC levels and the delta super(13)C of the organic matter (R super(2) = 0.89). The transport and settling of naturally-derived terrigenous material in the Ebro prodelta were reflected by the distribution of vascular plant n-alkanes. These refractory materials were preserved in the deep basin. Additionally, the distributions of fatty acids and sterols in the Ebro prodelta clearly evidenced algal signatures resulting from the enrichment of deltaic waters by nutrients transported by the river. Based on biomarker data a criterion is proposed to assess the percentage of terrestrial organic carbon in sediments, considering the river mouth sediment as the continental end-member. Fluxes of terrigenous organic inputs were calculated using sediment accumulation rates. Depositional flux estimates for the deltaic area off the Rhone River ( similar to 15 340 km super(2)) were as follows: 216 kg /year for capital sigma THC, 104 kg/year for retene, 11 t/year for terrestrial n-alkanes. The accumulation rates in the area of influence of the Ebro River ( similar to 12 600 km super(2)) were 69 kg/year for retene and 6 t/year for terrestrial n-alkanes. Comparison of these data with estimates of riverine inputs suggests that the bulk inputs of terrestrial biomarkers are trapped within the terminal part of the river bed and in the narrow prodeltaic area in front of the river mouths to a depth of approximately 70 m. Atmospheric deposition may also contribute to the accumulation of terrigenous materials in the deep basin.
AN: 4314936
31 of 313
TI: Production of carbonate particles by phytobenthic communities on the Mallorca-Menorca shelf, Northwestern Mediterranean Sea
AU: Canals,-M.; Ballesteros,-E.
AF: Associated Unit on Mar. Geosciences CSIC-UB, Dep. de Geologia Dinamica, Geofisica i P., Univ. de Barcelona, Nucli Universitari de Pedralbes, E-08071 Barcelona, Spain
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 611-629
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: In this paper the carbonate content and production, both at the species level and at the community level, is quantified in four areas of the Mallorca-Menorca shelf, northwestern Mediterranean Sea. Eight benthic communities are identified, each living at specific depth ranges and preferentially colonising either rocky or sedimented soft bottoms: (1) Photophilic algae, (2) Hemisciaphilic algae, (3) Coralligenous algal-dominated, (4) Coralligenous animal-dominated, (5) Caulerpa-Cymodocea meadows, (6) Posidonia oceanica meadows, (7) maerl and free-Peyssonelia beds, and (8) sandy bottom communities. Encrusting and maerl species of Corallinales and of the red algal genus Peyssonelia and, to a lesser extent, the green alga Halimeda tuna, are the main carbonate producers. Most of the modern algal carbonate production in the Mallorca-Menorca shelf occurs at depths of less than 85-90 m, which is the lower limit of the coralligenous and maerl communities. Algal carbonate production in rocky areas is usually higher than that of soft bottoms, with the exception of the maerl beds in moderately deep waters (40-85 m). The highest algal carbonate production is found in coralligenous algal-dominated rock bottoms (464.6 g m super(-2) year super(-1)), photophilic algal communities (289.4 g m super(-2) year super(-1)) and maerl beds (210 g m super(-2) year super(-1)), while the lowest is displayed by seagrass meadows (60 to 70 g m super(-2) year super(-1)) and sandy bottoms (0.5 g m super(-2) year super(-1)). Nevertheless, the contribution of seagrass beds to benthic carbonate production in the Mallorca-Menorca shelf is outstanding due to the extent of the area occupied by these beds. The mean algal carbonate production rate over the upper 100 m water depth in the studied localities ranges from 90.60 to 123.89 g m super(-2) year super(-1), which correspond to the mostly sedimented Campos area and to the very rocky South Cabrera area, respectively. Overall mean carbonate production of the Mallorca-Menorca shelf is around 100 g CO sub(3)Ca m super(-2) year super(-1). These results may be viewed as a minimum estimate for total carbonate production on the Mallorca-Menorca shelf since they take into account only the phytobenthos.
AN: 4314934
32 of 313
TI: 1-D Coupled physical-biological model of the northwestern Mediterranean Sea
AU: Tusseau,-M.-H.; Lancelot,-C.; Martin,-J.-M.; Tassin,-B.
AF: Inst. de Biogeochimie Mar., URA CNRS No. 386, Ecole Normale Superieure, 1, Rue M. Arnoux, 92 120 Montrouge, France
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 851-880
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: A 1-D coupled physical-biological model of the ecosystem of the Ligurian Sea is described. The physical model has been adapted from a thermal dispersive lake model, and the biological model from the sub-models AQUAPHY and H.S.B. The biological model considers two types of phytoplankton, diatoms and nonsiliceous flagellates, to describe the response of the phytoplankton community and the related food-web to different types of fertilization (by river, atmospheric deposition or deep water upwelling) with different N:Si ratios. This distinction, and the detailed description of the microbial loop, helps to distinguish between new and regenerated primary production. The model has been calibrated on FRONTAL 1986 data, obtained monthly at a long-term station (43 degree 24'N, 07 degree 52'E). The quantitative biomass, its repartition between diatoms and flagellates, and its spatio-temporal variability are reasonably well reproduced by the model. From these simulations, an annual new production of 62 g C/m super(2) is computed, contributing 35% of total annual primary production (180 g C/m super(2)). This calculation reflects the oligotrophic state of the system, where regenerated production occurs most of the year while the biomass remains low. A Monte-Carlo sensitivity analysis performed on the parameters driving the model leads to a confidence interval for the simulation and also to a better understanding of how the model functions.
AN: 4314933
33 of 313
TI: Dynamics of nitrogen and phosphorus retention during wetland ecosystem succession
AU: Craft,-C.B.
AF: Dep. Biol., Univ. Louisville, Louisville, KY 40292, USA
CO: International Workshop "Nutrient Cycling and Retention in Wetlands and Their Use in Wastewater Treatment", Trebon (Czech Rep.), 5-9 Sep 1995
SO: WETLANDS-ECOL.-MANAGE. 1997 vol. 4, no. 3, pp. 177-187
LA: English
AB: We compared the mechanisms of nitrogen (N) and phosphorus (P) removal in four young (<15 years old) constructed estuarine marshes with paired mature natural marshes to determine how nutrient retention changes during wetland ecosystem succession. In constructed wetlands, N retention begins as soon as emergent vegetation becomes established and soil organic matter starts to accumulate, which is usually within the first 1-3 years. Accumulation of organic carbon in the soil sets the stage for denitrification which, after 5-10 years, removes approximately the same amount of N as accumulating organic matter, 5-10 g/m super(2)/yr each, under conditions of low N loadings. Under high N loadings, the amount of N stored in accumulating organic matter doubles while N removal from denitrification may increase by an order of magnitude or more. Both organic N accumulation and denitrification provide for long-term reliable N removal regardless of N loading rates. Phosphorus removal, on the other hand, is greatest during the first 1-3 years of succession when sediment deposition and sorption/ precipitation of P are greatest. During this time, constructed marshes may retain from 3 g P/m super(2)/yr under low P loadings to as much as 30 g P/m super(2) /yr under high loadings. However, as sedimentation decreases and sorption sites become saturated, P retention decreases to levels supported by organic P accumulation (1-2 g P/m super(2)/yr) and sorption/ precipitation with incoming aqueous and particulate Fe, Al and Ca. Phosphorus cycling in wetlands differs from forest and other terrestrial ecosystems in that conservation of P is greatest during the early years of succession, not during the middle or late stages. Conservation of P by wetlands is largely regulated by geochemical processes (sorption, precipitation) which operate independently of succession. In contrast, the conservation of N is controlled by biological processes (organic matter accumulation, denitrification) that change as succession proceeds.
AN: 4314867
34 of 313
TI: Marine biological processes in polar region and global climate change
AU: Wang,-Zipan
AF: 2nd Inst. Oceanogr., SOA, Hangzhou 310012, People's Rep. China
SO: Donghai-Mar.-Sci.-Donghai-Haiyang 1997 vol. 15, no. 3, pp. 29-36
LA: Chinese
AB: In this paper, the transfer and flux of carbon and other biogenic material in marine biological processes, and its importance to global climate changeare discussed. the interrelationship among sea water, sea ice and marine organismsis also illusrated. Thus it expresses the significance of biological products affecting marine ecosystem and climate change in polar regions.
AN: 4313313
35 of 313
TI: Particulate lipid composition in waters of the Ob' River estuary and the southeastern Kara Sea
OT: Sostav lipidov vzvesi v vodakh ehstuariya Obi i yugo-vostochnoj chasti Karskogo morya
AU: Aleksandrova,-O.A.; Shevchenko,-V.P.
AF: IORAN, Moscow, Russia
SO: Okeanologiya 1997 vol. 37, no. 5, pp. 715-722
LA: Russian
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Content and distribution of particulate lipids along the Ob' River-Kara Sea profile (Russia) were studied by thin-layer chromatography with flame ionization detection (Iatroscan TH-10). The content of lipids varied from 18.4 to 266 mu g/L and constituted 4.06 to 58.32% of the total particulate organic matter. Major constituents of particulate lipids were hydrocarbons (an average of 32.14% of the total lipids), polar compounds (29.85%), wax and sterol esters (13.04%), and mono- and diglycerides (12.52). Composition of particulate lipids along the Ob' River-Kara Sea section is greatly influenced by the river discharge and reflects differences in the processes of organic matter transformation between the marine parts of the section as well as species composition of Arctic marine communities.
AN: 4313154
36 of 313
TI: Accumulation of sedimentary lipid biomarkers in the Kara Sea sediments
OT: Zakonomernosti akkumulyatsii lipidov-biomarkerov v vodnykh osadkakh Karskogo morya
AU: Belyaeva,-A.N.; Ehglinton,-Dzh.
AF: IORAN, Moscow, Russia
SO: Okeanologiya 1997 vol. 37, no. 5, pp. 705-714
LA: Russian
ER: M (Marine)
AB: Distribution of terrigenous, planktogenous and bacterial sedimentary lipids was studied by analysis of the molecular lipid composition in bottom sediments along the section from the Ob' River mouth (Russia) to 76 degree N. Terrigenous compounds were found to be dominant in all major lipid fractions (fatty acids, alcohols, alkanes) but their distribution along the section was irregular and decreased in the northern part of the section due to increasing accumulation of planktogenous lipids in consequence of transport of primarily synthesized organic matter by zooplankton.
AN: 4313153
37 of 313
TI: Tetrazolium reduction in acidic Sphagnum-derived peat
AU: Wieder,-R.K.; Yavitt,-J.B.; Gasda,-C.E.; Starr,-S.T.; Williams,-C.J.
AF: Dep. Biol., Villanova Univ., Villanova, PA 19085, USA
SO: WETLANDS 1998 vol. 18, no. 1, pp. 79-83
LA: English
ER: F (Freshwater)
AB: Assessment of how carbon storage in peat and gas fluxes across the peatland/atmosphere interface may be affected by predicted climate changes requires an understanding of the controls on C mineralization in peat. Toward this end, our goal was to develop the INT[2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride] reduction procedure for use in the field as a rapid and reliable approach to estimating C mineralization (CO sub(2) and CH sub(4) production) in peat under near-natural conditions with considerable spatial and temporal replication. Sphagnum peat samples collected from three sites were divided and analyzed for INT reduction activity, as well as for production of CO sub(2) and CH sub(4), under both oxic and anoxic conditions. For peat from each site, we found no significant relationships between INT reduction and oxic or anoxic CO sub(2) or CH sub(4) production. Although INT is reduced in acidic Sphagnum peat, INT reduction rates do not provide a usable index of C mineralization.
AN: 4310185
38 of 313
TI: Variability of pCO sub(2) in the Tropical Atlantic in 1995
AU: Lefevre,-N.; Moore,-G.; Aiken,-J.; Watson,-A.; Cooper,-D.; Ling,-R.
AF: Plymouth Mar. Lab., Plymouth, UK
SO: J.-GEOPHYS.-RES.-C-OCEANS 1998 vol. 103, no. C3, pp. 5623-5634
LA: English
ER: M (Marine)
AB: Atmospheric and oceanic partial pressures of CO sub(2) (pCO sub(2)) have been recorded automatically along two Atlantic meridional transects in 1995. The Tropical Atlantic ocean (20 degree S-20 degree N) is generally a source of CO sub(2) for the atmosphere, but in the region of the North Equatorial Countercurrent an undersaturation of CO sub(2) has been observed. Undersaturations previously reported in the literature are explained by the decrease of salinity due to the high precipitations associated with the Intertropical Convergence Zone. In June 1995, strong CO sub(2) undersaturations ( Delta pCO sub(2) = -70 mu atm) were observed near 8 degree N, which suggests, in addition of the salinity effect, an uptake of CO sub(2) due to biological activity. This undersaturation, although weaker than in spring, also appeared at other periods of the year 1995.
AN: 4310068
39 of 313
TI: Methane production and methane consumption: A review of processes underlying wetland methane fluxes
AU: Segers,-R.
AF: Department of Theoretical Production Ecology, Wageningen Agricultural University, PO Box 430, 6700 AK Wageningen, The Netherlands
SO: BIOGEOCHEMISTRY 1998 vol. 41, no. 1, pp. 23-51
LA: English
ER: F (Freshwater)
AB: Potential rates of both methane production and methane consumption vary over three orders of magnitude and their distribution is skew. These rates are weakly correlated with ecosystem type, incubation temperature, in situ aeration, latitude, depth and distance to oxic /anoxic interface. Anaerobic carbon mineralisation is a major control of methane production. The large range in anaerobic CH sub(4):CO sub(2) production rates indicate that a large part of the anaerobically mineralised carbon is used for reduction of electron acceptors, and, hence, is not available for methanogenesis. Consequently, cycling of electron acceptors needs to be studied to understand methane production. Methane and oxygen half saturation constants for methane oxidation vary about one order of magnitude. Potential methane oxidation seems to be correlated with methanotrophic biomass. Therefore, variation in potential methane oxidation could be related to site characteristics with a model of methanotrophic biomass.
AN: 4309278
40 of 313
TI: Long-term study of litter decomposition on a Pennine peat bog: Which regression?
AU: Latter,-P.M.; Howson,-G.; Howard,-D.M.; Scott,-W.A.
AF: 74 Jutland Avenue, Flookburgh, Grange over Sands, Cumbria LA11 7LQ, UK
SO: OECOLOGIA 1997 vol. 113, no. 1, pp. 94-103
LA: English
ER: F (Freshwater)
AB: It is estimated that in the northern hemisphere one-third of the world pool of soil carbon is contained in peat resulting from an incomplete decomposition of plant remains. The time course for the decomposition of the predominant plant litters on a Pennine moorland in northern England is reported for a study extending over 23 years. Spatial variation of the weight remaining of decomposing litters increased with time. This experimental study gave an age for the upper layers of the bog and a curve for long-term decay based on direct observation rather than inferred from profile samples or from short-term observations. It showed that short-term observations can give misleading results in the long term, with a variety of litters with differing early decay rates ultimately making a similar contribution to accumulation. Spatial variation of the weight remaining of the decomposing litters increased with time, so that variation within micro-environments, or within apparantly uniform substrates, may contribute significantly to organic matter accumulation. An asymptotic curve best described the long-term course of decomposition leading to the accumulation of peat. The use of the model for the three litter types, Calluna vulgaris, Eriophorum vaginatum and Rubus chamaemorus, is described and the implication of the results for modelling of organic matter accumulation are then discussed.
AN: 4308814
41 of 313
TI: Modelling the signal transfer of seawater delta super(18)O to the delta super(18)O of atmospheric oxygen using a diagnostic box model for the terrestrial and marine biosphere
AU: Leuenberger,-M.C.
AF: Climate and Environ. Phys., Univ. Bern, Bern, Switzerland
SO: J.-GEOPHYS.-RES.-C-OCEANS 1997 vol. 102, no. C12, pp. 26,841-26,850
LA: English
ER: M (Marine)
AB: We make use of a simple diagnostic box model to determine the sensitivities of the influencing parameters for the isotopic signal transfer of seawater oxygen to atmospheric oxygen. We calculate the delta super(18)O of atmospheric oxygen from prescribed oxygen fluxes of the living and dead biomes on land and in the ocean, respectively. The model is driven by an assumed (experiment 1) or measured (experiments 2 and 3) temporal seawater delta super(18)O signal and a land biomass estimation. In experiment 1, we calculated the required changes of several model parameters in order to study fast variations of delta super(18)O of atmospheric oxygen as seen in the Greenland Ice Core Project (GRIP) ice at depths assigned to the Eemian time period. Our calculations support evidence of stratigraphic problems at these depths in the GRIP ice core. In experiment 2, we adjusted the model output, which was driven by the benthic seawater delta super(18)O record from V19-30, to the measured Greenland Ice Sheet Project 2 delta super(18)O record of atmospheric oxygen for the last 110,000 years, by varying the model parameter. Single and multiparameter matchings were performed. The results for single-parameter runs exceed the uncertainty ranges for most of the parameters, while multiparameter variations are well within these ranges. The model calculations are most sensitive to the land respiration factor. Our results support the findings of Van de Water et al. [1994] that the fractionations associated with biomes activities were most probably lower during cold periods, which could point to a combination of fractionations with different temperature dependencies. The model results indicate periods of higher marine biological activity during the ice age than today. Temporal variations of the model parameters show a double peak around 10000 and 8000 years ago, which could be associated with meltwater pulses, as shown in experiment 3. However, they are hardly the well-known Fairbanks [Fairbanks et al., 1992] pulses since these occur 3000 to 4000 years earlier.
AN: 4296864
42 of 313
TI: Retention of NO sub(3) super(-) in an upland stream environment: A mass balance approach
AU: Burns,-D.A.
AF: U.S. Geol. Surv., 425 Jordan Rd., Troy, NY 12180, USA
SO: BIOGEOCHEMISTRY 1998 vol. 40, no. 1, pp. 73-96
LA: English
ER: F (Freshwater)
AB: Models of the effects of atmospheric N deposition in forested watersheds have not adequately accounted for the effects of aquatic and near-stream processes on the concentrations and loads of NO sub(3) super(-) in surface waters. This study compared the relative effects of aquatic and near-stream processes with those from the terrestrial ecosystem on the retention and transport of NO sub(3) super(-) in two contrasting stream reaches of the Neversink River, a forested watershed in the Catskill Mountains of New York that receives among the highest load of atmospheric N deposition in the northeastern United States. Results generally confirm that aquatic and near-stream processes cause significant losses of NO sub(3) super(-) in the Neversink River, and that the losses by these processes at downstream locations can exceed the NO sub(3) super(-) contributions to the stream from the terrestrial environment during summer and fall base-flow conditions. Failure to consider these aquatic and near-stream processes in models of watershed response to atmospheric N deposition could result in underestimates of the amount of NO sub(3) super(-) leaching from forested ecosystems and to an inability to unequivocally relate geographic differences in NO sub(3) super(-) concentrations of stream waters to corresponding differences in terrestrial processes.
AN: 4295551
43 of 313
TI: Net and gross sedimentation in relation to the phosphorus budget of Eau Galle Reservoir, Wisconsin
AU: James,-W.F.; Barko,-J.W.
AF: U.S. Army Engineer Waterways Experiment Stn., Eau Galle Aquatic Ecol. Lab., Spring Valley, WI 54767, USA
SO: HYDROBIOLOGIA 1997 vol. 345, no. pt. 1, pp. 15-20
NT: Special issue: Sediment-Water Interaction 7.
LA: English
ER: F (Freshwater)
AB: We compared P retention with direct measures of P sedimentation, estimated from sediment cores (annual P sedimentation) and sediment traps (daily P sedimentation), to quantify P sedimentation in Eau Galle Reservoir, Wisconsin. Mean annual P retention was similar to mean annual P sedimentation, as estimated from sediment core rates integrated over the entire lake basin, indicating that annual P mass balance approximated annual net P sedimentation in this reservoir. However, sediment trap P rates, measured over the summer stratified period, overestimated P retention rates determined over the same period, suggesting substantial deposition of internally-derived P. Inclusion of measured internal P loadings from a variety of sources in Eau Galle Reservoir in a P mass balance only accounted for an additional 24% of the summer sediment trap P rate, indicating substantial uncertainty in the overall P budget. Imbalances in the P budget may also suggest deposition of sediment from other as yet unquantified internal sources. Potential internal sources of P include sediment resuspension and chemical release and direct uptake of P from the sediment by phytoplankton.
AN: 4292773
44 of 313
TI: The types of aquatic ecosystems and their integral kinetic characteristics
AU: Gladyshev,-M.I.
AF: Inst. Biophys., Siberian Div., Russian Acad. Sci., Akademgorodok, Krasnoyarsk, 660036 Russia
SO: WATER-RESOUR.;VODNYE-RESURSY 1997 vol. 24, no. 5, pp. 484-489;vol. 24, no. 5, pp. 526-531
LA: English
ER: F (Freshwater)
AB: The hypothesis is proposed that a finite number of discrete types of ecosystems exist in time and space, and each type has its own definite integral functional (kinetic) characteristics. The notions of "general" and "specific" integral kinetic characteristics are considered. The hypothesis is substantiated based on the data on the kinetics of amino acid consumption by natural communities of microorganisms and on the kinetics of decay (self-purification) of phenols in natural water streams and bodies.
AN: 4291219
45 of 313
TI: Pyrite accumulation and sulfate depletion as affected by root distribution in a Juncus (needle rush) salt marsh
AU: Hsieh,-Y.P.; Yang,-C.H.
AF: Wetland Ecol. Prog., Florida A & M Univ., Tallahassee, FL 32307, USA
SO: ESTUARIES 1997 vol. 20, no. 3, pp. 640-645
LA: English
ER: M (Marine); B (Brackish)
AB: This study was undertaken to investigate patterns of pyrite accumulation found in a Juncus roemerianus tidal marsh of north Florida. We speculate that the pattern of pyrite accumulation was caused mainly by the distribution of roots. Sediment cores from living stands (LS), dead stands (DS), and recently killed stands (RKS) were collected and analyzed for dissolved organic carbon (DOC), sulfate, chloride, Cr(II)-reducible sulfide, and biomass of roots and rhizomes. Living roots were distributed mainly in the upper 16 cm and concentrated at 4-10 cm below the sediment surface. Pyrite accumulations were significantly different among the three types of sediment cores in the upper 16 cm sediment and follow the descending order of DS (615 mu mol cm super(-3)) > RKS (547 mu mol cm super(-3)) > LS (368 mu mol cm super(-3)). Between 20 cm and 30 cm, pyrite contents approached values of 40 mu mol cm super(-3) and 55 mu mol cm super(-3) in all sediment cores. The degree of pyritization approaches 92-94% between 14 cm and 20 cm where pyrite accumulation was probably limited by available iron. Root distribution also affected the redistribution of iron through iron sulfide formation. Sulfate depletion in the upper 16 cm was higher in RKS (79.3 mu mol cm super(-3)) than DS (49.1 mu mol cm super(-3)). No significant sulfate depletion was found in LS. Sulfate reduction under DS was likely limited by the readily available substrates. Root distribution had a major influence on pyrite accumulation and sulfate reduction of the marsh, and its effects need to be addressed in studies of wetland sulfur dynamics.
AN: 4290674
46 of 313
TI: Spatial distribution of acid-volatile sulfur in the sediments of Canadohta Lake, PA, [USA]
AU: Oehm,-N.J.; Luben,-T.J.; Ostrofsky,-M.L.
AF: Dep. Biol., Allegheny Coll., Meadville, PA 16335, USA
SO: HYDROBIOLOGIA 1997 vol. 345, no. pt. 1, pp. 79-85
NT: Special issue: Sediment-Water Interaction 7.
LA: English
ER: F (Freshwater)
AB: Lake sediments are an important source of dissolved substances and can be the site of processes important to the biogeochemical cycling of nutrients and metals. Most studies which examine these processes, however, are based on the analysis of a single or a very few sediment cores taken at or near the deepest area of the lake. The implicit assumption is that lake sediments are spatially homogeneous and that extrapolations from such limited samples are representative of the lake sediments throughout the lake basin. We examined this assumption with respect to concentrations of acid volatile sulfides (S super(2) super(-) sub(vol)) - sulfur species which have been implicated in eutrophication, acid-neutralization, and heavy-metal toxicity. S super(2) super(-) sub(vol) concentrations measured in the surficial sediments of Canadohta Lake, PA, a lake of very simple morphometry, ranged from 0.07 to 30.32 mu g g super(-1) sediment dry weight. Concentrations were directly correlated with depth and inversely correlated with organic matter. These results suggest that results extrapolated from a few deep-water cores can lead to a serious overestimation of S super(2) super(-) sub(vol) in the lake sediments.
AN: 4288846
47 of 313
TI: An autobiotic wetland phosphorus model
AU: Kadlec,-R.H.
AF: Wetland Manage. Serv., 6995 Westbourne Dr., Chelsea, MI 48118-9527, USA
SO: ECOL.-ENG. 1997 vol. 8, no. 2, pp. 145-172
LA: English
ER: F (Freshwater)
AB: Constructed and natural wetlands are capable of absorbing new phosphorus loadings, and in appropriate circumstances can provide a low cost alternative to chemical and biological treatment. Phosphorus (P) interacts strongly with wetland soils and biota, which provide both short term and sustainable long term storage of this nutrient. Soil sorption may provide initial removal, but this partly reversible storage eventually becomes saturated. Uptake by biota, including bacteria, algae, and duckweed, as well as macrophytes, forms an initial removal mechanism. Cycling through growth, death and decomposition returns most of the biotic uptake, but an important residual contributes to long term accretion in newly formed sediments and soils. Despite the apparent complexity of these several removal mechanisms, data analysis shows that relatively simple equations can describe the sustainable processes. Previous global first order removal rates characterize the sustainable removal, but do not incorporate any biotic features. This paper presents an autobiotic model, based upon cycling through the biomass compartments, and calibrates it to data from 17 years of operation of the Houghton Lake, MI treatment wetland. This model replaces a first order concentration-based rate with a first order biomass-based rate. When coupled with mass balances, it describes the spatial distribution of both biomass and P concentrations, as well as the evolution of the new standing crop.
AN: 4282512
48 of 313
TI: Effect of biogeochemical diagenesis on sediment fabric in shallow marine carbonate sediments near the Dry Tortugas, Florida
AU: Furukawa,-Y.; Lavoie,-D.; Stephens,-K.
AF: Institute of Marine Sciences, University of Southern Mississippi, Stennis Space Center, MS 39529, USA
SO: Geo-Mar.-Lett. 1997 vol. 17, no. 4, pp. 283-290
NT: Special issue: Benthic boundary layer processes in the Lower Florida Keys.
LA: English
AB: Shallow marine carbonate sediments near the Dry Tortugas undergo extensive biogeochemical diagenesis upon deposition, resulting in postdepositional fabric comprised of micritic aggregates of clay-sized particles, a matrix of peloidal mud, and intraparticular cementation. Freshly deposited primary skeletons, mostly Halimeda fragments, yield micritic aggregates of clay-sized particles, which then form peloidal mud fabric upon compaction. The cryptocrystalline particles produced by micritization are later replaced by high magnesian calcite. Cementation is observed in the intra-particular microenvironment. However, no inter-particular, grain-binding cement was detected throughout the gravity core samples investigated.
AN: 4269888
49 of 313
TI: Benthic boundary layer processes in the Lower Florida Keys
AU: Lavoie,-D.L.; Richardson,-M.D.; Holmes,-C.
AF: Marine Geosciences Division, Naval Research Laboratory, Stennis Space Center, MS 39529-5004, USA
SO: Geo-Mar.-Lett. 1997 vol. 17, no. 4, pp. 232-236
NT: Special issue: Benthic boundary layer processes in the Lower Florida Keys.
LA: English
AB: This special issue of Geo-Marine Letters, "Benthic Boundary Layer Processes in the Lower Florida Keys," includes 12 papers that present preliminary results from the Key West Campaign. The Dry Tortugas and Marquesas Keys test sites were selected by a group of 115 scientists and technicians to study benthic boundary layer processes in a carbonate environment controlled by bioturbation and biogeochemical processes. Major activities included remote sediment classification; high-frequency acoustic scattering experiments; sediment sampling for radiological, geotechnical, biological, biogeochemical, physical, and geoacoustic studies; and hydrodynamic studies using an instrumented tetrapod. All these data are being used to improve our understanding of the effects of environmental processes on sediment structure and behavior.
AN: 4269881
50 of 313
TI: Effects of dissolved organic carbon and salinity on bioavailability of mercury
AU: Barkay,-T.; Gillman,-M.; Turner,-R.R.
AF: Dep. Mol. Microbiol. and Biotechnol., Tel Aviv Univ., Ramat Aviv 69978, Israel
SO: APPL.-ENVIRON.-MICROBIOL. 1997 vol. 63, no. 11, pp. 4267-4271
LA: English
ER: F (Freshwater)
AB: Hypotheses that dissolved organic carbon (DOC) and electrochemical charge affect the rate of methylmercury [CH sub(3)Hg(I)] synthesis by modulating the availability of ionic mercury [Hg(II)] to bacteria were tested by using a mer-lux bioindicator (Escherichia coli). A decline in Hg(II)-dependent light production was observed in the presence of increasing concentrations of DOC, and this decline was more pronounced at pH 7 than at pH 5, suggesting that DOC is a factor controlling the bioavailability of Hg(II). A thermodynamic model (MINTEQA2) was used to select assay conditions that clearly distinguished among various Hg(II) species. By using this approach, it was shown that negatively charged forms of mercuric chloride (HgCl sub(3) super(-)/HgCl sub(4) super(2-)) induced less light production than the electrochemically neutral form (HgCl sub(2)), and no difference was observed between the two neutral forms, HgCl sub(2) and Hg(OH) sub(2). These results suggest that the negative charge of Hg(II) species reduces their availability to bacteria and may be one reason why accumulation of CH sub(3)Hg(I) is more often reported to occur in freshwater than in estuarine and marine biota.
AN: 4268223
51 of 313
TI: Spatial distribution and inhibition by ammonium of methane oxidation in intertidal freshwater marshes
AU: Van-der-Nat,-F.-J.W.A.; De-Brouwer,-J.F.C.; Middelburg,-J.J.; Laanbroek,-H.J.
AF: Cent. for Estuarine and Coastal Ecol., Netherlands Inst. Ecol., Yerseke, The Netherlands
SO: APPL.-ENVIRON.-MICROBIOL. 1997 vol. 63, no. 12, pp. 4734-4740
LA: English
ER: F (Freshwater)
AB: In two intertidal marshes, the vertical distribution in the sediment and inhibition by ammonium of methane oxidation were investigated by slurry incubation experiments. The two sites differ in their dominant vegetation type, i.e., reed and bulrush, and in their heights above sea level. The reed site was elevated with respect to the bulrush site, resulting in a lower frequency and duration of flooding and, consequently, a higher potential for methane oxidation. Methane oxidation decreased with depth in the bulrush and reed slurries, although methane oxidation associated with root material from the bulrush plants increased with depth. Reed root material had a limited capacity for methane oxidation and showed no significant increase with depth. Inhibition of methane oxidation by ammonium was observed in all samples and depended on methane and ammonium concentrations. Increasing ammonium concentrations resulted in greater inhibition, and increasing methane concentrations resulted in less. Ammonium concentrations had to exceed methane concentrations by at least 30-fold to become effective for inhibition. This ratio was found only in the surface layer of the sediment. Hence, the ecological relevance for ammonium inhibition of methane oxidation in intertidal marshes is rather limited and is restricted to the surface layer. Nitrate production was restricted to the 0- to 5-cm-depth slurries.
AN: 4266459
52 of 313
TI: Reconstructing the iron cycle from the horizontal distribution of metals in the sediment of Baldeggersee
AU: Schaller,-T.; Moor,-H.C.; Wehrli,-B.
AF: Limnological Res. Cent., Swiss Federal Inst. for Environ. Sci. and Technol. (EAWAG), CH-6047 Kastanienbaum, Switzerland
SO: AQUAT.-SCI. 1997 vol. 59, no. 4, pp. 326-344
NT: Special issue: High resolution varve studies in Baldeggersee.
LA: English
ER: F (Freshwater)
AB: In Baldeggersee, the distributions of solid phase Fe, Mn, V, Cr, As and Mo were determined in different sediment strata, deposited under various deep-water oxygen conditions. Iron concentrations are correlated with water depth when an anoxic sediment is in contact with an oxic water column. Benthic redox gradients trigger iron transport towards the deepest site (geochemical focusing) and loss of iron from the shallower parts through the outflow. Fe cycling in the lake is inhibited by oxygen penetration into the sediment. Vanadium and arsenic can be used as tracers for the internal Fe cycle. Their distribution patterns are highly correlated with iron. In case of a stable oxycline in the deep water, Mo is enriched in the sediment and correlates with Mn. The horizontal distribution patterns of Fe, V, As and the correlation of Fe and Mn with trace metals are promising proxy indicators for the reconstruction of deep-water oxygen conditions during deposition.
AN: 4265716
53 of 313
TI: Spatio-temporal variability of the thermohaline and biogeochemical properties and dissolved organic carbon in a coastal embayment affected by upwelling: the Ria de Vigo (NW Spain)
AU: Doval,-M.D.; Nogueira,-E.; Perez,-F.F.
AF: Inst. de Investigacions Marinas, CSIC, Eduardo Cabello, 6, 36208 Vigo, Spain
SO: J.-MAR.-SYST. 1998 vol. 14, no. 1-2, pp. 135-150
LA: English
ER: M (Marine)
AB: Hydrographic sampling was carried out along the main axis of the Ria de Vigo, from May 1994 to September 1995, to observe the spatio-temporal evolution of hydrographic and biogeochemical properties of the water column. Meteorology controls mainly the hydrography and biogeochemistry of the Ria. Two periods can be distinguished on a seasonal time-scale: the upwelling season, from March to October and the non-upwelling season, from November to February. A strong coupling was observed between meteorological, hydrographic and biogeochemical processes. The Ria behaves like an extension of the shelf during the upwelling season and like a partially mixed estuary during the non-upwelling season. Dissolved organic carbon was related to the thermohaline properties in the whole water column, and with oxygen and chlorophyll a in the surface layer. Extreme values were recorded during the upwelling season: the highest values (> 100 mu M), in the surface layer during upwelling relaxations and the lowest values (< 70 mu M), in the bottom layer in upwelled waters. Dissolved organic carbon maxima decrease shelfward thus suggesting export of dissolved organic carbon, in addition to particulate organic carbon, from the Ria to the shelf.
AN: 4265703
54 of 313
TI: Comparison of iron, manganese, and phosphorus retention in freshwater littoral sediment with growth of Littorella uniflora and benthic microalgae
AU: Christensen,-K.K.; Andersen,-F.O.; Jensen,-H.S.
AF: Odense University, Institute of Biology, Campusvej 55, DK-5230 Odense M, Denmark
SO: BIOGEOCHEMISTRY 1997 vol. 38, no. 2, pp. 149-171
LA: English
ER: F (Freshwater)
AB: Sediment columns from an oligotrophic lake were percolated with artificial porewater in two 46-day experiments to examine the effects of Littorella uniflora and benthic microalgae on retention of phosphorus (P) by either iron (Fe) or manganese (Mn). Cumulative retention of P, Fe, and Mn was 2-5 times higher in sediment with L. uniflora than in sediment with microalgae, because of higher P uptake and more efficient Fe and Mn oxidation by L. uniflora than by microalgae. Thus 34% and 21% of added P was retained in L. uniflora inhabited sediments as metal-oxide bound P compared to 11% and 2% in microalgae inhabited sediments, in experiments supplied with Fe and Mn, respectively. The atomic ratio of Fe/P precipitation was about 1 and for Mn/P precipitation it was about 5. These ratios indicate precipitation of Fe(III)-phosphate (strengite) and metastable Mn(IV)-compounds containing phosphate and hydroxide ions in variable amounts. In addition to metal-oxide P precipitation, increased P retention in the vegetated sediment was also caused by the presence of humic acid compounds, which accounted for about 26% of total retained P.
AN: 4264658
55 of 313
TI: Onset of a spring diatom bloom in the Ross Sea, November and December 1994: Timing and effects on nutrient and biogenic silica distributions
AU: Nelson,-D.M.; Gordon,-L.I.; Arrington,-J.M.; Ross,-A.A.
AF: College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
SO: Antarct.-J.-U.S. 1995 vol. 30, no. 5, pp. 207-209
LA: English
AB: We have carried out past collaborative studies of the cycling of biogenic silica and organic matter in the Ross Sea, for the purpose of understanding the processes that lead to the rich siliceous deposits in antarctic sediments (e.g., Nelson, Ahern, and Herlihy 1991; DeMaster et al. 1992; Nelson and Treguer 1992). A major goal of that work has been to obtain reliable estimates of the annual production of biogenic silica in surface waters, permitting the regional silica cycle to be evaluated quantitatively by comparison of production in the upper ocean with vertical transport.
AN: 4261103
56 of 313
TI: Agglutinated test morphogenesis in Astrammina rara, a giant foraminiferan protist from Explorers Cove, McMurdo Sound
AU: Bowser,-S.S.; Kinoshita,-R.K.; Bernhard,-J.M.; Hayden,-J.H.
AF: Wadsworth Center, Albany, NY 12201, USA
SO: Antarct.-J.-U.S. 1995 vol. 30, no. 5, pp. 161-162
LA: English
ER: M (Marine)
AB: Agglutinated foraminifera are protists that sculpt elegant tests (shells) by using their pseudopodia to collect mineral grains and secreting bioadhesives to hold the grains together. Agglutinated foraminifera are among the most abundant metazoans in deep-sea sediments, and evidence is accumulating that they may play important roles in nutrient cycling and community structure in the deep-sea benthos (reviewed in Gooday et al. 1992, pp. 63-91). For over a decade, Explorers Cove has served as an important site for conducting biological studies on agglutinated foraminifera because, uniquely, large numbers of deep-sea-like species can be collected and studied in situ by scuba divers (see, for example, DeLaca 1986; DeLaca, Lipps, and Hessler 1980; DeLaca, Karl, and Lipps 1981). Our current studies focus on agglutinated test morphogenesis in Astrammina rara, one of the most conspicuous members of the Explorers Cove foraminiferal assemblage. This species is highly selective for more than 500-micrometer sand grains and binds these grains together with a fibrous adhesive to form a spherical test (Bowser and Bernhard 1993). The goals of recent work are to determine how Astrammina's adhesive matrix is secreted and to characterize the mechanical properties of the matrix by performing finite element analysis of the intact shell. The results of these studies will provide insights into possible biotechnological uses for adhesives secreted by foraminifera.
AN: 4261079
57 of 313
TI: Photochemistry of antarctic waters during the 1994 austral summer
AU: Kieber,-D.J.; Mopper,-K.
AF: Department of Chemistry, State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210, USA
SO: Antarct.-J.-U.S. 1995 vol. 30, no. 5, pp. 150-151
LA: English
AB: Solar radiation in natural waters initiates a wide variety of photochemical transformations, ranging from simple photolyses involving well-defined chromophores to complicated photoreactions involving ill-defined humic substances. The broad spectrum of photochemical transformations that have been documented attest to the importance of photochemistry in aquatic biogeochemical cycles. Perhaps the most interesting photochemical transformations are the formation of reactive species (e.g., the OH radical) and the production of substrates (e.g., pyruvate), since these processes represent a day-time stress and food source for plankton, respectively. The nature and extent of these photochemical-biological interactions in antarctic waters are not known, but it can be expected that they will be accelerated during an "ozone hole" because of an increase in the flux of ultraviolet-B (UV-B) radiation in the water column.
AN: 4261073
58 of 313
TI: Fluxes of copper-complexing ligands from estuarine sediments
AF: Department of Chemistry, University of North Carolina at Wilmington, Wilmington, NC 28403, USA
SO: Limnol.-Oceanogr. 1997 vol. 42, no. 5, pp. 992-996
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Most studies of the organic complexation of Cu in natural waters have focused on distributions and processes in the water column, where a significant fraction of Cu-complexing ligands may be biologically produced. We present direct evidence for a flux of Cu-complexing ligands from estuarine sediments, demonstrating that sediments are a significant, yet previously unrecognized source of the ligands. Fluxes of Cu-complexing ligands from Chesapeake Bay sediments range from 300 to 1,200 nmol m super(-2) d super(-1), exceeding fluxes of total dissolved Cu by 3->40-fold, suggesting that any Cu fluxing from the sediments is likely to be organically complexed. Our results indicate that benthic fluxes may supply from 10 to 50% of the standing stock of Cu-complexing ligands in Chesapeake Bay and suggest that such fluxes may strongly influence the biogeochemistry of Cu in shallow water environments and potentially in the ocean as a whole.
AN: 4258722
59 of 313
TI: The origin of sedimenting detrital matter in a coastal system
AF: Marine Biological Laboratory, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingor, Denmark
SO: Limnol.-Oceanogr. 1997 vol. 42, no. 5, pp. 1001-1005
LA: English
ER: M (Marine)
AB: Total sedimentation and the fraction due to copepod fecal pellets were measured during the growth season (March-October 1989) in the southern Kattegat, Denmark. In this period the sedimentation of detritus made up 52 g C m super(-2), equal to 82% of the sedimenting matter from the euphotic zone, but fecal pellets (11 g C m super(-2)) constituted only a minor fraction. The remaining detrital matter was produced by other heterotrophs than copepods. Published data on heterotrophic biomass and grazing obtained during the investigation in the Kattegat are reviewed in order to relate the sedimentation to processes in the pelagic system. Copepod defecation nearly equaled the sedimentation of fecal pellets, indicating that retention of this matter in the pelagic system was insignificant. A considerable fraction (10-24%) of the carbon flow processed by heterotrophic pico-, nano-, and microplankton was converted to detritus that was lost from the mixed system by sedimentation. The microbial food web is thus not an exclusively regenerating system.
AN: 4258718
60 of 313
TI: Evaluation of super(32)Si as a tracer for measuring silica production rates in marine waters
AU: Brzezinski,-M.A.; Phillips,-D.R.
AF: Department of Ecology Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA
SO: Limnol.-Oceanogr. 1997 vol. 42, no. 5, pp. 856-865
LA: English
ER: M (Marine)
AB: The radioisotope super(32)Si was evaluated as a tracer for measuring silica production rates in marine waters. super(32)Si is a weak beta -emitter that decays to super(32)P allowing the isotope to be used to determine simultaneously the production rate of biogenic silica and organic phosphorus. High specific activity super(32)Si, 42,000-52,000 Bq ( mu g Si) super(-1), was produced by the proton spallation of KCl. Reasonable tracer additions result in only nanomolar increases in the ambient silicic acid and orthophosphate concentrations during production rate experiments. Protocols for quantifying the amount of super(32)Si and super(32)P in samples by liquid scintillation counting (LSC) and gas-flow proportional counting (GFPC) are presented. Both protocols eliminate the 4-month wait for secular equilibrium between super(32)Si and super(32)P required by earlier methods. GFPC is especially useful as the instrumentation is lightweight and portable allowing real-time analysis of samples at sea. Real-time analysis by GFPC at sea and postcruise analysis by LSC gave results that agreed to within 17 and 7% for super(32)Si and super(32)P, respectively. Subsequent intercalibrations of the LSC and GFPC methods indicated that agreement to within 0.1-4% for both isotopes can be achieved. Parallel incubations of samples from Monterey Bay, California, using the radioisotope super(32)Si and the stable isotope super(30)Si gave silica production rates that generally agreed to within 30%. No significant bias was observed between rates obtained with the two tracers. The greater sensitivity and ease of analysis of the radioisotope makes super(32)Si the tracer of choice for future studies of silica production in the ocean.
AN: 4258703
61 of 313
TI: Transport and fate of dissolved organic carbon in the Lake Pontchartrain estuary, Louisiana, U.S.A.
AU: Argyrou,-M.E.; Bianchi,-T.S.; Lambert,-C.D.
AF: Dep. Ecol., Evolution and Organismal Biol., Tulane Univ., New Orleans, LA 70118, USA
SO: BIOGEOCHEMISTRY 1997 vol. 38, no. 2, pp. 207-226
LA: English
AB: Cycling dynamics of dissolved organic carbon (DOC) were examined in Lake Pontchartrain estuary, Louisiana, in relation to changes in freshwater inputs. DOC concentrations ranged from 5.3 to 8.5 mg C L super(-1) reaching their highest during high river inflow. The percentage of DOC represented by HMW DOC (or colloidal material) was greatest (ca. 11%) at stations where freshwater discharge from rivers and surrounding wetlands was most significant. Moreover, the lignin-phenol content of this material ( lambda ranged from 0.09 to 0.33 and Lambda from 0.11 to 0.39) confirmed that a significant fraction of colloidal organic carbon was derived from terrestrial sources. Riverine and benthic fluxes represented the dominant sources of DOC to the estuary. On an annual basis, riverine and benthic DOC concentrations were estimated to be 2.8 x 10 super(10) g C yr super(-1) and 8.8 x 10 super(10) g C yr super(-1), respectively, while the total DOC pool in the estuary was 3.8 x 10 super(10) g C. Annual average concentrations of dissolved inorganic carbon (DIC) (1298 mu M) and pCO sub(2) (5774 mu atm) were comparable to those found in other freshwater systems that reached CO sub(2) saturation levels. Net losses of DOC in the Lake Pontchartrain estuary appeared to be primarily controlled by heterotrophic consumption (conversion of CO sub(2)) - which may have been amplified by the long residence time (approximately 120 days) of DOC in this system.
AN: 4256247
62 of 313
TI: Influence of sulfur-oxidizing bacteria on the budget of sulfate in Yugama crater lake, Kusatsu-Shirane volcano, Japan
AU: Takano,-B.; Koshida,-M.; Fujiwara,-Y.; Sugimori,-K.; Takayanagi,-S.
AF: Dep. Chem., Coll. Arts and Sci., Univ. Tokyo, Komaba, Meguro-ku, Tokyo 153, Japan
SO: BIOGEOCHEMISTRY 1997 vol. 38, no. 3, pp. 227-253
LA: English
ER: F (Freshwater)
AB: Sulfur-oxidizing bacteria, Thiobacillus thiooxidans, were found in a highly acidic (pH = 1 similar to 1.5) crater lake, Yugama, seasonally flowing streams and soil in the catchment area of the crater. Thiobacillus ferrooxidans was also found in some of the streams but not in the lake itself. The lake water contains aqueous carbon dioxide, hydrogen sulfide, polythionates and elemental sulfur in suspension which are the substrates for the growth of the sulfur-oxidizing bacteria as no organic compounds except for the microorganisms themselves were detected. The bacteria isolated from the Yugama water preferred polythionates in the following order: S sub(4)O sub(6) super(2-)>S sub(5)O sub(6) super(2-)>S sub(6)O sub(6) super(2-). On the other hand, H sub(2)S was more rapidly consumed by the bacteria than polythionates which were followed by elemental sulfur. In the case of test-tube incubation, the optimum pH of the solution for growth of the bacteria was between 1.0 and 1.5, and for cultivation in growth medium plates between 2.5 and 3.5. The bacteria hardly proliferated at pH 0.5 or below. In accordance with these characteristics of the bacteria, numbers of the bacteria in the surface Yugama crater lake water were at minimum (<a few cells/mL) in February and at maximum (10 super(6) cell/mL) in August. The bacterial activity changed in accordance with the surface lake water temperature, but not necessarily with the variations in H sub(2)S and polythionates concentrations of the lake water. Based on the variation in sulfur isotope ratios of sulfate and experimentally determined rate of oxidation of H sub(2)S in the lake water, the sulfate production rate by the bacteria in the catchment area and the lake were estimated to 9.5 and 8.4 g/m super(2)/day, respectively, during the period from 1988 to 1990 when the volcanic activity at Yugama was at minimum. Also stream, hydrothermal, H sub(2)S-oxidated SO sub(4) super(2-) inputs and outputs by seepage and precipitation have been calculated as 4.1, 32, 0.56, 36, and 1.2 ton/day, respectively.
AN: 4256167
63 of 313
TI: Quantification of organic matter degradation by microbial sulphate reduction for Quaternary sediments from the northern Arabian Sea
AU: Littke,-R.; Lueckge,-A.; Welte,-D.H.
AF: Inst. fuer Erdoel und Organische Geochemie (ICG-4), Forschungszentrum Juelich GmbH, D-52425 Juelich, Germany
SO: NATURWISSENSCHAFTEN 1997 vol. 84, no. 7, pp. 312-315
LA: English
ER: M (Marine)
AN: 4254168
64 of 313
TI: Annual cycle of heavy metals in a tropical lake- Lake Chapala, Mexico
AU: Shine,-J.P.; Ryan,-D.K.; Ford,-T.E.
AF: Harvard Sch. Public Health, Dep. Env. Health, 665 Huntington Ave., Boston, MA 02115, USA
SO: J.-Environ.-Sci.-Health,-Pt.-A:-Toxic-Hazard.-Subst.-Environ.-Eng. 1998 vol. A33, no. 1, pp. 23-43
LA: English
AB: Dissolved concentrations of seven metals (As, Pb, Cd, Zn, Ni, Cu, Cr) were determined monthly at six sampling stations in Lake Chapala, Mexico, between November 1990 and December, 1991. Lake Chapala is the largest lake in Mexico, and serves as a source of drinking water and an economically important fishery and center for tourism. Historically, Lake Chapala has received poorly characterized domestic, industrial, and agricultural wastes. As, Cd, Pb, Cr, and Zn displayed peaks in concentration during the period before the rainy season due, presumably, to evaporation. Comparison of inflow and outflow concentrations also indicated a direct source of As to the lake. During this period, the concentrations of both Cd and Pb were above the freshwater chronic criteria values recommended by the United States Environmental Protection Agency for protection of aquatic ecosystem health. The metals As, Cr, Zn, Ni, and Cu also showed concentrations peaks following the rainy season in August and September, perhaps due to increased input from the watershed or resuspension of metals in the lake driven by changes in water circulation patterns. Concentration data for the lake also suggested that a portion of the inflow water does not immediately mix with the lake as a whole, creating spatial gradients depending on the concentration of metals in the source water. Determination of metals in water hyacinth (Eichornia crassipes) plant tissue showed large partitioning of metals into root tissue, indicating that plants may be an important temporal sink for metals. In addition, copper and zinc accumulated to very high levels in Tilapia and Carp livers, indicating that some of the metal contaminants are entering the food chain.
AN: 4280575
65 of 313
TI: Methyl halides from Antarctic macroalgae
AU: Laturnus,-F.; Adams,-F.C.; Wiencke,-C.
AF: Plant Biol. and Biogeochemistry Dep., Riso Natl. Lab., Bldg. 124, PO Box 49, DK-4000 Roskilde, Denmark
SO: GEOPHYS.-RES.-LETT. 1998 vol. 25, no. 6, pp. 773-776
LA: English
ER: M (Marine)
AN: 4300582
66 of 313
TI: Dissolved dimethylsulphide, dimethylsulphoniopropionate and dimethylsulphoxide in western Mediterranean waters
AU: Simo,-R.; Grimalt,-J.O.; Albaiges,-J.
AF: Dep. Environ. Chem. (CID-CSIC), Jordi Girona, 18, 08034 Barcelona, Catalonia, Spain
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 929-950
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: Spring-summer concentrations of the three main dissolved dimethyl sulphur species (DMSS sub(d)), dimethylsulphide (DMS), dimethylsulphoniopropionate (DMSP sub(d)) and dimethylsulphoxide (DMSO), have been determined in western Mediterranean Sea water with some spatial and temporal resolution. Depth profiles showed that the three DMSS sub(d) were mostly confined to the euphotic layer. In surface waters, DMSO was generally the dominant DMSS sub(d) regardless of the site and the season. Concentration averages resulted in a DMS:DMSP sub(d):DMSO proportion of 1: 1: 6 (2.9: 3.0: 16.6 nM). DMSS sub(d) concentrations exhibited a great variability, but were higher on the continental shelf than in open seawaters, as were chlorophyll concentrations. Some hot spots with the highest levels were identified off the main continental outflows. None of the DMSS sub(d) correlated significantly with chlorophyll. In open seawaters (water column depth >200 m) DMS increased as chlorophyll declined between April and July. This was attributed to changes in the biological community from spring development to summer decay and ecological succession. The temporal variation of the three DMSS sub(d)s suggests that they are subject to a tight cycling of production and consumption where the composition of the entire planktonic community, as well as its physiological state, play a significant role. A similar conclusion was achieved from the study of the DMSS sub(d) concentrations in a transect between oligotrophic and eutrophic waters in the top NW area. Finally, the western Mediterranean has been assessed as a source of atmospheric sulphur. The moderate DMS emission flux estimates (mean: 5.4 mu mol/m super(2)/day) together with the moderate DMS surface concentrations, were consistent with the low productivity of the Mediterranean Sea.
AN: 4290948
67 of 313
TI: Dynamics of the vernal bloom in the marginal ice zone of the Barents Sea: Dimethyl sulfide and dimethylsulfoniopropionate budgets
AU: Matrai,-P.A.; Vernet,-M.
AF: Bigelow Lab. for Ocean Sci., West Boothbay Harbor, ME, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1997 vol. 102, no. C10, pp. 22,965-22,979
LA: English
ER: M (Marine)
AB: Phytoplankton is known to be a key element in the production and eventual oceanic efflux of dimethyl sulfide (DMS) to the atmosphere. We hypothesized that the alternation of Phaeocystis pouchetii and diatoms, the two major algal components of the spring bloom, would modulate the input of particulate organic sulfur (POS), dimethylsulfoniopropionate (DMSP), and DMS into the mixed layer of the marginal ice zone. A bloom of diatoms is expected to present similar pathways but to have very different rates of POS/DMSP/DMS production and POS/DMSP sinking and no or low DMS flux to the atmosphere as contrasted to the cycling occurring during the P. pouchetii phase of the bloom. Our initial hypothesis cannot be accepted based on our observations in the Barents Sea during the spring of 1993. The contribution of diatoms to the water column budgets of DMSP and DMS was significant and cannot be overlooked. We suggest that the physiological stage of the bloom is perhaps more important to biogeochemical cycling than its phytoplankton species composition in controlling DMSP and DMS fluxes in Arctic waters. Loss of particulate DMSP in the mixed layer was mainly by release into the dissolved pool and by sedimentation rather than by grazing, except in ice-free waters. Cycling of DMS in the mixed layer was predominantly biological in ice-free waters, while in Polar Front waters, ventilation was proportionally more important due to depressed microbiology.
AN: 4290535
68 of 313
TI: Biogeochemical significance of transport exopolymer particles in the Indian Ocean
AU: Dileep-Kumar,-M.; Sarma,-V.V.S.S.; Ramaiah,-N.; Gauns,-M.; De-Sousa,-S.N.
AF: Natl. Inst. Oceanogr., Dona Paula, Goa, India
SO: GEOPHYS.-RES.-LETT. 1998 vol. 25, no. 1, pp. 81-84
LA: English
ER: M (Marine)
AN: 4290501
69 of 313
TI: A one-dimensional physical-biological model study of the pelagic nitrogen cycling during the spring bloom in the northern North Sea (FLEX '76)
AU: Kuehn,-W.; Radach,-G.
AF: Inst. fuer Meereskunde, Univ. Hamburg, Troplowitzstr. 7, D-22529 Hamburg, Germany
SO: J.-MAR.-RES. 1997 vol. 55, no. 4, pp. 687-734
LA: English
ER: M (Marine)
AB: A one-dimensional model of the pelagic ecosystem was developed and applied to the spring bloom in the northern North Sea making use of the data set obtained during the Fladenground experiment FLEX '76. The physical submodel is the second-order turbulence closure model of level 2 type developed by Mellor and Yamada (1974, 1982). The biological submodel is a depth-resolved version of the nitrogen flux model of the lower trophic levels in the pelagic proposed by Fasham et al. (1990). The parameter set employed by Fasham et al. did not yield satisfying results. However, using a parameter set adapted to the North Sea ecosystem we obtained a realistic overall description of the development of the North Sea ecosystem during the spring bloom. We were able to hindcast successfully the onset, duration, magnitude and daily variability of the net primary production, the magnitude of the PON export flux to the sea bottom, of the bacterial production and of the nitrogen regeneration within the water column. From the results of the simulation a mass budget of nitrogen fluxes within the euphotic zone and the deeper water layers as well as between them was derived. The results of the simulation suggest that strong herbivorous grazing caused the decay of the bloom. The comparison with the grazing by mesozooplankton as estimated from the observations favors the hypothesis that herbivorous microzooplankton was mainly responsible for the breakdown. The depth dependence of the vertical particulate flux obtained from the simulation exhibits the hyperbolic character recently found in different oceanic regions. The vertical particulate nitrogen flux shows a stronger decrease than typically observed for the particulate carbon flux. This is in correspondence with the observation that there was a remarkable increase of the C /N ratio of POM with depth during FLEX '76.
AN: 4290440
70 of 313
TI: Effect of naturally occurring bromophenols on sulfate reduction and ammonia oxidation in intertidal sediments
AU: Giray,-C.; King,-G.M.
AF: Darling Mar. Cent., Univ. Maine, Walpole, ME 04573, USA
SO: AQUAT.-MICROB.-ECOL. 1997 vol. 13, no. 3, pp. 295-301
LA: English
ER: M (Marine)
AB: We examined the effect on ammonium oxidation and sulfate reduction of several brominated compounds [4-bromophenol, 2,4-dibromophenol (2,4-DBP), 2,6-dibromophenol and 2,4,6-tribromophenol] that occur naturally in enteropneusts. We compared rates of these processes with and without bromoorganics using bulk intertidal sediments and burrow wall sediments from 3 enteropneust species (2 containing 2,4-DBP and 1 containing 2,3,4-tribromopyrrole), a mollusc (Mya arenaria) and a polychaete (Nereis virens). Sulfate reduction in bulk sediment was unaffected by bromophenols at concentrations <100 nmol cm super(-3) sediment, but was inhibited temporarily at 1 mu mol cm super(-3). Sulfate reduction in burrow wall sediments differed from bulk sediments, but was not correlated with concentrations of naturally occurring bromophenols. Ammonium oxidation was inhibited in surface sediments by bromophenol concentrations as low as 1 nmol cm super(-3) sediment. Ammonium oxidation was enhanced in burrow wall sediments of N. virens, M. arenaria and the enteropneust Saccoglossus bromophenolosus relative to surface sediments, but was markedly lower and negatively correlated with ambient 2,4-DBP in burrow wall sediments of a second enteropneust, Protoglossus graveolens.
AN: 4282105
71 of 313
TI: Dissimilatory nitrate reduction in anaerobic sediments leading to river nitrite accumulation
AU: Kelso,-B.H.L.; Smith,-R.V.; Laughlin,-R.J.; Lennox,-S.D.
AF: Dep. Agric. and Environ. Sci., Queen's Univ. Belfast, Newforge Lane, Belfast BT9 5PX, UK
SO: APPL.-ENVIRON.-MICROBIOL. 1997 vol. 63, no. 12, pp. 4679-4685
LA: English
AB: Recent studies on Northern Ireland rivers have shown that summer nitrite (NO sub(2) super(-)) concentrations greatly exceed the European Union guideline of 3 mu g of N liter super(-1) for rivers supporting salmonid fisheries. In fast-flowing aerobic small streams, NO sub(2) super(-) is thought to originate from nitrification, due to the retardation of Nitrobacter strains by the presence of free ammonia. Multiple regression analyses of NO sub(2) super(-) concentrations against water quality variables of the six major rivers of the Lough Neagh catchment in Northern Ireland, however, suggested that the high NO sub(2) super(-) concentrations found in the summer under warm, slow-flow conditions may result from the reduction of NO sub(3) super(-). This hypothesis was supported by field observations of weekly changes in N species. Here, reduction of NO sub(3) super(-) was observed to occur simultaneously with elevation of NO sub(2) super(-) levels and subsequently NH sub(4) super(+) levels, indicating that dissimilatory NO sub(3) super(-) reduction to NH sub(4) super(+) (DNRA) performed by fermentative bacteria (e.g., Aeromonas and Vibrio spp.) is responsible for NO sub(2) super(-) accumulation in these large rivers. Mechanistic studies in which super(15)N-labelled NO sub(3) super(-) in sediment extracts was used provided further support for this hypothesis. Maximal concentrations of NO sub(2) super(-) accumulation (up to 1.4 mg of N liter super(-1)) were found in sediments deeper than 6 cm associated with a high concentration of metabolizable carbon and anaerobic conditions. The super(15)N enrichment of the NO sub(2) super(-) was comparable to that of the NO sub(3) super(-) pool, indicating that the NO sub(2) super(-) was predominantly NO sub(3) super(-) derived. There is evidence which suggests that the high NO sub(2) super(-) concentrations observed arose from the inhibition of the DNRA NO sub(2) super(-) reductase system by NO sub(3) super(-).
AN: 4268224
72 of 313
TI: Remote sensing of coccolithophore blooms in the western South Atlantic Ocean
AU: Brown,-C.W.; Podesta,-G.P.
AF: Satellite Res. Lab., NOAA/NESDIS E/RA13, Washington, DC 20233, USA
SO: REMOTE-SENS.-ENVIRON. 1997 vol. 60, no. 1, pp. 83-91
LA: English
ER: M (Marine)
AB: High-reflectance patches are regularly observed off the southeastern coast of South America during the late austral spring and summer in visible satellite imagery of the Coastal Zone Color Scanner (CZCS). Unfortunately, coincident in situ samples for identifying their cause are lacking. To ascertain the likelihood that these patches represent surface blooms of the coccolithophore Emiliania huxleyi, their distribution pattern was mapped and their spectral signature evaluated by classifying CZCS imagery with a supervised, multispectral classification scheme that had been developed to detect this phytoplankton species. On the basis of the similarity of these characteristics to those of documented cases, we conclude that the high-reflectance patches observed in surface waters of the shelf and beyond are E. huxleyi blooms. The blooms seasonally occupied an area as large as 550,000 km super(2). Standing stock estimates indicate that the detected blooms produced an average of 1.5-4.9 x 10 super(5) metric tons of calcite carbon and 4.0 x 10 super(3) t of dimethyl sulfide sulfur. The bloom's production of these climatically relevant compounds and their alteration of optical properties in the surface layer suggest that the blooms significantly affect the biogeochemistry and ecology of this region.
AN: 4265445
73 of 313
TI: In situ measurement of particulate organic matter removal rates by a tidal flat macrobenthic community
OT: Higata jo ni okeru makurobentosu gunshu ni yoru yuki kendakubutsu jokyosokudo no genba sokutei
AU: Aoyama,-Hiroaki; Suzuki,-Teruaki
AF: Aichi Prefect. Fish. Res. Inst., Miya-cho, Gamagori 443, Japan
SO: Bull.-Jap.-Soc.-Fish.-Oceanogr. 1997 vol. 61, no. 3, pp. 265-274
LA: Japanese
ER: M (Marine)
AB: Special transparent chambers were set at four stations on Isshiki tidal flat of Mikawa Bay to measure the in situ removal rates of particulate organic matter by the macrobenthic community. Concentrations of particulate organic nitrogen, carbon and chlorophyll pigment were measured and filtering rates was calculated with each chamber. The filtering rates per unit of macrobenthos biomass were almost equal in all chambers, with average value 21.7 l/g N/h which was 35 % less than the past data obtained under artificial laboratory condition. Characterstically, the filtering rate was proportional to the whole macrobenthos biomass rather than that of the suspension feeders. The removal rate of particulate organic nitrogen on Isshiki tidal flat was 227.4 mg N/m super(2)/day as calculated by the filter feeding rate and the average concentration of particulate organic nitrogen on the tidal flat. This rate was compared to the nitrogen budget ( 150 mg N/m super(2)/day) obtained by the BOX model analysis for the same period. Generally these values were in good agreement, assuming that about 60 % of the excrement of suspension feeding macrobenthos was resuspended and consumed again as food.
AN: 4281336
74 of 313
TI: Bacterial utilization of glucose in the water column from eutrophic to oligotrophic pelagic areas in the eastern North Atlantic Ocean
AU: Bianchi,-A.; Van-Wambeke,-F.; Garcin,-J.
AF: Microbiologie Mar. (C.N.R.S.-I.N.S.U., UPR 223), Univ. de la Mediterranee, Fac. des Sci. de Luminy, Case 907, 13288 Marseille Cedex 9, France
SO: J.-MAR.-SYST. 1998 vol. 14, no. 1-2, pp. 45-55
LA: English
ER: M (Marine)
AB: Vertical profiles of glucose utilization rates were compared at three sampling stations in the eastern part of the tropical North Atlantic Ocean. The investigation area was along 20-21 degree N and the three sampling sites, characterised by differences in their primary productivity, were located at 18 degree W, 21 degree W and 31 degree W. In the superficial waters, maximum (V sub(max)) glucose utilization (respiration plus incorporation) depended on the nutritional load being 20-fold higher in the eutrophic, compared to the oligotrophic zone. Due to these variations, natural turnover times for this labile compound were approximately 1 day in the eutrophic area, and up to 435 days in the oligotrophic area. Bacterial activity showed a steep decline immediately below the mixed layer in the mesotrophic and eutrophic areas and below the deep chlorophyll maximum in the oligotrophic area. Discrepancies between microbial activities in the three areas decreased with increasing depth: at depths below 250 m potential utilization rates of glucose were similar whatever the nutrient richness of the photic layer. Nevertheless, the distribution of microbial activities through the whole water column depended greatly on the productivity of superficial waters. In nutrient-rich areas 73% of glucose utilization activity was realized in the productive upper layer, whereas only 4% was metabolized at depths below 250 m. Conversely, in the oligotrophic area, more than 40% of the glucose utilized in the whole water column was processed in the intermediate and deep-water masses. Integration of V sub(max) values for the whole water column, suggested potential carbon fluxes due to bacterial utilization of glucose of 6 and 34 mg C m super(-2) d super(-1) in the oligotrophic and eutrophic areas, respectively. The fate of the metabolised carbon depended on the nutrient availability. In the mixed-water layer the glucose respiration percentage (%R) increased from 30% in nutrient-rich areas to 60% under oligotrophic conditions, moreover %R increased with depth. This infers that at lower nutritional loads, a greater proportion of highly labile compounds is used for energetic purposes, and therefore return to the inorganic carbon pool, but with very low turnover rates.
AN: 4282122
75 of 313
TI: Palmer LTER: Project SANTA CLA mu S: December 1994
AU: Karl,-D.M.
AF: School of Ocean and Earth Science and Technology, Department of Oceanography, University of Hawaii, Honolulu, HI 96822, USA
SO: Antarct.-J.-U.S. 1995 vol. 30, no. 5, pp. 252-254
LA: English
AB: Microorganisms, including unicellular algae, bacteria, viruses, protozoans, and small metazoans, are vital components of Southern Ocean habitats (Karl 1993). They are largely responsible for the production and decomposition of organic matter, for the primary uptake and regeneration of inorganic nutrients, and for export of carbon and energy to intermediate ocean depths. Furthermore, microbial growth and metabolism can have a profound effect on sea water pH and redox state and, therefore, can influence the distribution, speciation, and availability of certain elements and compounds. Consequently, field data both on individual groups of microorganisms and on the complex interactions among them are necessary for a complete assessment of the role of marine microorganisms on both local and global environments.
AN: 4261005
76 of 313
TI: The effects of sewage organic matter on biogeochemical processes within mid-shelf sediments offshore Sydney, Australia
AU: Bickford,-G.P.
AF: Dep. Geol. and Geophysics, Univ. Sydney, Sydney, NSW 2006, Australia
SO: MAR.-POLLUT.-BULL. 1997 vol. 33, no. 7-12, pp. 168-181
NT: Special issue: Ocean Outfalls - Sustainable Solution?
LA: English
ER: M (Marine)
AB: A laboratory incubation experiment was conducted using replicate cores collected from a muddy-sand sediment facies offshore Sydney, Australia to determine what components and processes would be affected by the addition of sewage organic matter. Sewage effluent has a solid phase composition of 40% carbon (35% organic carbon), 5% nitrogen, 1% phosphorus and 5% silicate. The molecular C:N:P ratio is 92:10:1, compared to the Redfield ratio of 106:16:1 in marine phytoplankton. Sediment cores were incubated at in situ temperature in a darkened room for periods up to 95 days. Sewage organic matter was added to the cores at three different loads equivalent to 0 (T0), 65 (T1) and 130 (T2) g m super(-2) of sediment. Following the addition of sewage organic matter, fluxes of oxygen (into the sediments), ammonia and phosphate (from the sediments) increased, reflecting an enhanced organic carbon supply to the sediments. Oxygen penetrated to a depth of 6 mm in the ambient cores, but the sediment oxygen content was severely depleted following the addition of the sewage-derived organic matter. Sediment porewater data, together with nutrient flux data indicate that oxygen reduction, nitrate reduction and sulphate reduction occurs within these sediments. Following the addition of sewage organic matter, increases in total nitrogen, total phosphate and total organic carbon were measured to depths of 5 cm in the sediments, suggesting that bioturbation influences nutrient and organic carbon distributions. Additionally, irrigation of the surficial sediments may play an important role in the metabolism of organic matter. These results indicate that oxygen penetration, oxygen fluxes, nitrate concentrations within porewaters, ammonia flux rates, and solid phase concentrations of total organic carbon and nutrients may be useful indicators of sediments affected by high rates of organic matter deposition onto Sydney's offshore sediments. The EPA has recently predicted maximum deposition rates of sewage particulate matter to be approximately 1 g m super(-2) day super(-1). Because of the similarities in CNP ratios of sewage organic matter and marine organic matter, the effects of sewage organic matter and marine organic matter inputs to coastal sediments may not be easily distinguishable.
AN: 4254038
77 of 313
TI: Phosphorus regeneration in continental margin sediments
AU: McManus,-J.; Berelson,-W.M.; Coale,-K.H.; Johnson,-K.S.; Kilgore,-T.E.
AF: Oregon State Univ., COAS, Ocean Admin. Bldg. 104, Corvallis, OR 97331-5503, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1997 vol. 61, no. 14, pp. 2891-2907
LA: English
ER: M (Marine)
AB: Benthic incubation chambers have been deployed in a variety of geochemical environments along the California Continental Margin. These include both high and low oxygen environments and sites where the rate of organic matter oxidation on the seafloor (C sub(ox)) ranges from <1 mmol m super(-2) day super(-1) to more than 7 mmol m super(-2) day super(-1) through a depth range of 100-3500 m. This range in the rate of organic matter oxidation along with variations in the concentration of bottom water oxygen allow us to elucidate the diagenetic conditions under which P regeneration may be decoupled from organic matter cycling. Under conditions where bottom water oxygen concentration is low (<50 mu M), and the rate of organic matter oxidation is also low (<1 mmol m super(-2) day super(-1)), P regeneration may be less than that expected from the decay of organic debris and, in some cases, there is a flux of phosphate into the sediments. At stations where bottom water oxygen is low, and the degradation rate of organic material is greater than 1 mmol m super(-2) day super(-1), phosphate may be released at a rate exceeding the production expected from the oxidation of organic matter. At stations having high bottom water oxygen concentrations, rates of organic matter decomposition < similar to 7 mmol m super(-2) day super(-1), and where benthic irrigation is not significant, P regeneration is consistent with that expected from the decomposition of organic debris. In addition, our data indicate that high benthic iron fluxes are observed in regions exhibiting a decoupling between organic matter and phosphate, whereas low to zero iron fluxes are observed in regions where P regeneration is either consistent with or less than that expected from the decomposition of organic material. These results support previous work suggesting a coupling between iron cycling and phosphate cycling in suboxic environments. Data presented here show that this coupling may result in either preferential phosphate burial or release relative to organic material in suboxic environments.
AN: 4248919
78 of 313
TI: Acetate cycling in the water column and surface sediment of Long Island Sound following a bloom
AU: Wu,-Hanguo; Green,-M.; Scranton,-M.I.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11794-5000, USA
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 4, pp. 705-713
LA: English
ER: M (Marine)
AB: A number of workers have suggested that rates of acetate cycling in sediments may approximate the rates of anaerobic decomposition of organic matter. However, few studies have examined whether this relationship holds over very short time scales, such as those encountered during the deposition of the spring bloom into coastal sediments. In this study, we measured acetate concentrations and uptake rate constants in surface and bottom waters and in the top few centimeters of sediment in Long Island Sound. Samples were collected every 2-3 weeks from early spring to early summer of 1993. Acetate concentrations varied from 85 to 530 nM in the water column and from <2 to 29.8 mu M sub(sed) in pore water. Acetate concentrations in pore water showed a strong depth variation, with a concentration maximum in the surface few millimeters, as well as a strong temporal variation. The concentration of acetate averaged over the top 4 cm varied from about 5 mu M sub(sed) in the early spring to 14.3 mu M sub(sed) following the addition of spring bloom-derived organic carbon. Acetate uptake rate constants in the water column varied from 0.0012 to 0.037 h super(-1) (turnover time 33.4 to 1.13 d). The average uptake rate constants in the sediment over the top 4 cm varied from 0.07 to 0.59 h super(-1) (turnover time 0.59 to 0.07 d) and tended to increase over the course of the experiment in both the sediment and the water column. In the water column, acetate uptake rates (calculated as rate constant times concentration) varied from less than one nanomole per liter per hour in the early spring to tens of nanomoles per liter per hour in the early summer. In the sediment over the same period, acetate uptake rates averaged over the top 4 cm varied from 0.13 to 5.25 mu M sub(s) sub(e) sub(d) super(-1) h super(-1). Rates of acetate metabolism to CO sub(2) agreed within a factor of two to estimates of the capital sigma CO sub(2) flux from the sediments, and both increased sharply following the deposition of the spring bloom. However, because temperatures were also increasing during this period, we are unable to separate unambiguously the effects of supply of labile carbon and of temperature on the acetate uptake rate.
AN: 4237657
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TI: Dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in relation to phytoplankton in the Gulf of Maine
AU: Townsend,-D.W.; Keller,-M.D.
AF: Department of Oceanography, 5741 Libby Hall, University of Maine, Orono, ME 04469, USA
SO: Mar.-Ecol.-Prog.-Ser. 1996 vol. 137, no. 1-3, pp. 229-241
LA: English
ER: M (Marine)
AB: Dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP), in both particulate and dissolved forms, were surveyed during the early spring (March and April) and summer (July) of 1991 in coastal and offshore waters of the Gulf of Maine, USA, along with the hydrography, inorganic nutrients, phytoplankton chlorophyll, and phytoplankton taxonomic composition and abundance. Concentrations as high as 15 nM DMS (in April and July), 208 nM particulate DMSP (in April), and 101 nM dissolved DMSP (in July) were recorded. Total DMSP (dissolved plus particulate) reached 293 nM in a patch of the dinoflagellate Katodinium in April. This is the first report of high DMSP concentrations in temperate waters in early spring associated with any organism other than the prymnesiophyte Phaeocystis pouchetii. There were no correlations between phytoplankton biomass, as measured by chlorophyll a, and DMS, and there were only slight correlations between chlorophyll a and DMSP in either dissolved or particulate form. As previously demonstrated by others, concentrations of intracellular (particulate) DMSP were related more to the presence of specific phytoplankton species rather than to overall phytoplankton biomass. The occurrence of high DMSP and DMS levels in early spring, comparable with or higher than those seen in summer maxima, at a time when bacterial activity is minimal and wind speeds are typically high may result in enhanced air-sea-fluxes of DMS.
AN: 4213491
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TI: Sulphate reduction in the root zone of the seagrass Zostera noltii on the intertidal flats of a coastal lagoon (Arcachon, France)
AU: Isaksen,-M.F.; Finster,-K.
AF: Institute of Biological Sciences, Department of Microbia, DK-8000 Aarhus, Denmark
SO: Mar.-Ecol.-Prog.-Ser. 1996 vol. 137, no. 1-3, pp. 187-194
LA: English
ER: M (Marine)
AB: Rates of sulphate reduction were determined in sediments from the eutrophic Bay of Arcachon, France. A comparison was made between sediment overgrown with the eelgrass Zostera noltii and unvegetated sediment. Rates of sulphate reduction were about twice as high in the root zone from 1 to 4 cm depth in the Z. noltii sediments (about 600 nmol/cm super(3)/d) as compared to the activity in the equivalent layer of the unvegetated sediment. The sulphate reduction in the root zone was not stimulated by light, which in other studies with other submersed macrophytes has been shown to promote sulphate reduction due to heightened excretion of organic molecules. Furthermore, in a field experiment, we were not able to detect any diurnal variation in the activity within the root zone. The stimulation of sulphate reduction by the presence of the Z. noltii was most likely due to degradation of leaf and root fragments which were found mixed into the sediment. Incubation times with radioactive sulphate had to be kept very short (preferably 15 min) to avoid a substantial reoxidation of sulphide and hence an underestimation of the rate of sulphate reduction.
AN: 4213487
81 of 313
TI: Denitrification in a coastal sediment measured n situ by the nitrogen isotope pairing technique applied to a benthic flux chamber
AU: Nielsen,-L.P.; Glud,-R.N.
AF: Institute of Biology, Department of Microbial Ecology, University of Aarhus, Ny Munkegade, bygn. 540, DK-8000 Arhus C, Denmark
SO: Mar.-Ecol.-Prog.-Ser. vol. 137, no. 1-3, pp. 181-186
LA: English
ER: M (Marine)
AB: A free operating benthic flux chamber lander (ELINOR) was used to measure in situ denitrification rates in the Aarhus Bight, Denmark (16 m depth). After insertion of the flux chamber into the sediment super(15)NO sub(3) super(-) was automatically injected into the enclosed water phase. After 3 to 4 h of incubation ELINOR was brought back to the surface with an intact water and sediment phase. Dinitrogen was extracted and later analyzed for super(15)N enrichment by mass spectrometry. Parallel sediment cores were sampled for laboratory incubation under in situ conditions. In situ denitrification rates in June and November were 350 and 470 mu mol N/m super(2)/d respectively, and were not significantly different from the laboratory measured rates of 290 and 500 mu mol N /m super(2)/d, respectively. Oxygen uptake was 40% lower in the laboratory incubated cores compared to in situ measurements, apparently due to lowered activity of the dominating species of infauna, the bivalve Abra alba. Nitrate concentrations were low in the bottom water (<8 mu M) and most of the denitrification activity (65 to 100%) was coupled to nitrification in the sediment. A laboratory test showed that the addition of super(15)NO sub(3) super(-) did not significantly impede the reduction rate of the natural unlabelled NO sub(3) super(-). The results support the validity of laboratory measurements for coastal waters and demonstrate the potential of combining benthic flux chamber landers and the isotope pairing technique for accurate measurements of denitrification in shelf, deep sea, and freshwater environments.
AN: 4213486
82 of 313
TI: PCBs in the Western Mediterranean. Temporal trends and mass balance assessment
AU: Tolosa,-I.; Readman,-J.W.; Fowler,-S.W.; Villeneuve,-J.P.; Dachs,-J.; Bayona,-J.M.; Albaiges,-J.
AF: IAEA Mar. Environ. Lab., BP 800, MC-98012, Monaco, Monaco
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 907-928
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: Comparison of data reported for polychlorinated biphenyl (PCB) concentrations in different environmental compartments of the western Mediterranean (dissolved and particulate phases of water, sediment and biota) over the last two decades shows a substantial decline in PCB concentrations, which coincides with legislated restrictions in the use of these compounds. Nevertheless, localised chronic ("hotspot") contamination continues, which underscores the importance of these compounds as environmental contaminants in certain specific areas of the region. Data on depositional fluxes are used to estimate and model transport processes to investigate the fate of these chemicals in the study area. A tentative mass balance of the compounds suggests that dry and wet deposition (12 t /year) account for most of the input. This compares with approximately 1 t/year discharged from rivers and sewage outfalls into coastal environments. Sedimentation is estimated to remove 5 t /year from the water column. Losses through volatilization are difficult to model owing to the critical dependance within calculations on atmospheric and dissolved seawater concentrations, for which very few data exist.
AN: 4273816
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TI: Mass budget and dynamics of polycyclic aromatic hydrocarbons in the Mediterranean Sea
AU: Lipiatou,-E.; Tolosa,-I.; Simo,-R.; Bouloubassi,-I.; Dachs,-J.; Marti,-S.; Sicre,-M.-A.; Bayona,-J.M.; Grimalt,-J.O.; Saliot,-A.; Albaiges,-J.
AF: European Commission, Mar. Sci. and Technol. Programme (MAST), Directorate Gen. XII, 200 Rue de La Loi, 1040 Brussels, Belgium
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 881-905
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: A mass budget was constructed to examine the status and dynamics of polycyclic aromatic hydrocarbons (PAHs) in the western Mediterranean Sea. Using gas chromatography-mass spectrometry, 11 PAHs have been quantified in atmospheric aerosols, rivers and seawater, sediment cores and sediment trap samples. Total PAH concentrations in Mediterranean aerosols range from 0.2 to 2 ng /m super(3) with 50-70% associated with the sub-micron particles. Maximum PAH concentrations were observed in winter when the concentrations were double those recorded in the spring. Total PAH inputs from the atmosphere were estimated to be from 35 to 70 t/year with a mean value of 47.5 t/year (wet/dry mean ratio of similar to 2-3). Atmospherically-deposited PAH are dominated by the benzofluoranthenes. The total PAH riverine inputs amount to about 5.3-33 t/year from the Rhone River and 1.3 t/year from the Ebro River. The difference in these riverine fluxes is due to differences in annual water discharges and upstream land use. The total PAH accumulation rate in surficial sediments in the whole basin is estimated at 182 t/year. Nearly 50% of the total PAHs accumulate in the 0-200 m water depth area supporting the importance of the coastal zone as a trap of terrigenous material and associated contaminants. Sediment trap experiments gave a mean residence time in the water column of total PAH (considering only particle settling) of 11 years, with higher residence times for high molecular weight PAHs. This supports the hypothesis that lower molecular weight PAHs are more efficiently removed from the water column. Water exchange resulted in a net outflow of 20 t/year and 2 t/year through the Gibraltar and Sicilian Straits, respectively. Atmospheric deposition and the Rhone River are the major contributors of PAH in the western Mediterranean. Sedimentation was identified as the major net output of PAH.
AN: 4273817
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TI: The distribution and cycling of mercury species in the western Mediterranean
AU: Cossa,-D.; Martin,-J.-M.; Takayanagi,-K.; Sanjuan,-J.
AF: Inst. Francais de Recherches pour l'Exploitation de la Mer, BP 21105, F44311 Nantes Cedex 03, France
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 721-740
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: Total mercury concentrations were determined in water samples from ten vertical profiles in the western Mediterranean. Most Hg concentrations ranged from 0.5 to 4 pM, with a geometric mean of 2.26 pM. Such concentrations are in the same range as those measured in the North Atlantic and equatorial Pacific waters. There is no indication that the presence of geothermal activity or cinnabar deposits around the Mediterranean basin induces higher mercury concentrations in waters. Vertical concentration profiles were characterized by a maximum just below the thermocline, which is mainly developed in regions with relatively high primary production in the overlying waters. These observations support the remobilization model according to which, the mercury, associated with degradable organic matter, is solubilized from the particles accumulated in the thermocline layer. Additional measurements of certain mercury species, including reactive mercury (Hg sub(R)) and gaseous species [elemental mercury (Hg degree ) and dimethylmercury (DMHg)], were performed on three profiles in the Alboran Sea and the Strait of Gibraltar. While 50% of the total mercury consisted of unidentified organic association, a maximum of the three determined species were observed below the thermocline: up to 0.71 pM, 0.43 pM and 0.30 pM for Hg sub(R), Hg degree and DMHg, respectively. DMHg and Hg degree appear to be formed in the low oxygen zone. A specific methylation rate of 3 x 10 super(-9)/s can be estimated, which is six times higher than the values proposed for the North Atlantic waters. The mass balance budget in the western Mediterranean shows that, while the total mercury exchanges at the straits are not unbalanced, mercury enters the Mediterranean as inorganic mercury and is exported to the Atlantic Ocean partially as methylated species. Riverine input is mainly composed by particulate mercury which is readily accumulated in coastal sediments. The dissolved mercury flux from non-marine sources is largely dominated by atmospheric deposition, which is one order of magnitude higher than riverine input. The mercury accumulation rate in the sediments is quantitatively equivalent to the atmospheric inputs, but mainly constituted by terrestrial material deposited nearshore. On the basis of box-core analyses and the global model of Mason et al. (1994), and present results the pre-industrial Hg riverine, atmospheric and sedimentation fluxes are estimated to have been about one-third the current one.
AN: 4273818
85 of 313
TI: Biogeochemical behavior and mass balance of dissolved aluminum in the western Mediterranean Sea
AU: Chou,-Lei; Wollast,-R.
AF: Lab. d'Oceanographie Chimique, Univ. Libre de Bruxelles, Campus de la Plaine-C.P. 208, B-1050 Brussels, Belgium
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 741-768
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: The biogeochemical cycle of dissolved aluminum in the western Mediterranean has been thoroughly investigated during the EROS 2000 program. Measurements of the concentration of this element were carried out for 5 years both in the water column and in the pore waters of the sediment. Special attention was paid to the distribution of dissolved Al in the river plumes of the Rhone and Ebro. The vertical profiles of this element in the vicinity of the straits of Gibraltar and Sicily also were determined in order to quantify the exchange fluxes of Al at these two boundaries. Budget calculations indicate that the mass balance of the input and output fluxes is fairly well constrained. They also show that atmospheric dust of Saharan origin is by far the most important external source of dissolved Al for the western Mediterranean and thus is responsible for the anomalously high concentrations of this element observed in the water column. Data obtained in this study strongly support the hypothesis that the unusual nutrient-like vertical distribution is controlled mainly by biological activity. Calculations of renewal times of dissolved Al imply that its concentration and distribution can be affected significantly at time scales of a few decades if the atmospheric input is modified. Presently the net input flux of dissolved Al to the western Mediterranean is entirely exported to the Atlantic.
AN: 4273819
86 of 313
TI: EROS 2000 (European River Ocean System). The western Mediterranean: An introduction
AU: Martin,-J.-M.; Milliman,-J.D.
AF: Environ. Inst., Joint Res. Cent., European Commission, 21020 Ispra, Italy
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 521-529
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine); B (Brackish)
AB: The EROS 2000 project is an attempt to understand the biogeochemical processes and their alteration by human activity in the European coastal zone. More specifically, EROS 2000 addresses the following questions: What is the role of the estuarine and coastal environment in sequestering organic and inorganic carbon and in the exchange of carbon dioxide across the air-sea interface, and how do these processes affect the global carbon cycle? What is the role of the coastal ocean in the production of other greenhouse gases, such as compounds of nitrogen and sulphur? To what extent is the residence time of elements and compounds in the ocean controlled by the transformation and accumulation of organic and inorganic matter in the estuarine and coastal environment? What is the receiving capacity of the coastal ocean for pollutants of riverine and atmospheric origin? What are the socioeconomic consequences of environmental changes, particularly those induced by climatic modifications and by human impact on the coastal zone? The basic rationale of the EROS 2000 project was to carry out field investigations and modeling activities on estuary/shelf-sea systems representing the contrasting environmental characteristics of European waters that have different levels of pollution and eutrophication, and very different tidal regimes. First studies in 1988 in the northwestern Mediterranean revealed the paucity of systematic and reliable information for the majority of inorganic and organic constituents in the water column and sediments as well as for inputs from riverine and atmospheric sources.
AN: 4273823
87 of 313
TI: Transfer mechanisms and biogeochemical implications in the bottom nepheloid layer. A case study of the coastal zone off the Rhone River (France)
AU: Naudin,-J.J.; Cauwet,-G.
AF: GDR "Interactions Continent-Ocean", Lab. Arago, B.P. 44, F-66651 Banyuls sur mer Cedex, France
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 551-575
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: Particles supplied to the coastal zone are involved in numerous biogeochemical processes that rapidly modify particulate composition. The Bottom Nepheloid Layer (BNL) thus plays a significant role on the budget of elements transferred to the coastal zone. Although it should not be ignored in flux studies, little is known about the quantity and the quality of particles transported within it, mainly due to sampling difficulties. From field experiments in the coastal zone off the Rhone River, the physical mechanisms occurring within the BNL were delineated. Its temporal variability was then examined, regarding the influence of wind, river discharge and current velocity, in order to investigate the temporal scales that control the BNL's character and the processes occurring within it. In the BNL off the Rhone, particulate transfer can be as important, quantitatively, as in the river plume, and larger by far than within the water column.
AN: 4273825
88 of 313
TI: Hydrodynamic prevention of eutrophication in the Bay of Brest (France), a modelling approach
AU: Le-Pape,-O.; Menesguen,-A.
AF: Lab. DEL/CMCN, IFREMER, BP 70, 29280 Plouzane, France
CO: 27. Int. Liege Colloquium on Ocean Hydrodynamics, Liege (Belgium), 8-12 May 1995
SO: Journal-of-Marine-Systems 1997 vol. 12, no. 1-4, pp. 171-186
NT: Special Volume: Processes in Regions of Freshwater Influence (PROFILE)
LA: English
ER: M (Marine); B (Brackish)
AB: The Bay of Brest is a semi-enclosed coastal ecosystem where primary production is nutrient-limited, even if huge nutrients loading from tributaries are present. The most striking feature of the bay is the semi-diurnal tidal influence, resulting in large water exchange with the continental shelf. A historical study of the available data has shown the steadiness of this ecosystem during the two last decades in spite of increasing eutrophic conditions. This study has focused on hydrodynamic exchange which is one of the factors supposed to explain the resistance of this ecosystem to eutrophication: this stirring hinders the formation of a persistent upper mixed layer where phytoplankton would be in contact with nutrient-rich brackish waters and available light. Moreover, horizontal tidal currents lead to huge exchanges with the Iroise Sea and, then, to big losses of nutrients and living matter. To study this hydrodynamic influence thoroughly, a physical/biological model of this bay has been developed. This box model, based on the horizontal tidal circulation, has been developed thanks to "ELISE", an ecological modelling software and, then, tuned and validated on two data sets corresponding with the years 1977 and 1993. The model has allowed us to quantify the influence of hydrodynamics, climatic conditions and biological factors on biogeochemical processes in this ecosystem. It contributes to explain the good resistance of the Bay of Brest ecosystem to eutrophic conditions; both the hydrodynamic properties of this bay and the grazing pressure have prevented it from disturbances caused by high nitrogen loading from the watersheds and explain the steadiness of phytoplankton stocks in spite of increased loading. So, these results allow us to say that, even if nitrogen inputs increase continues, phytoplankton stocks will not increase in significant proportions. Nevertheless, changes in the phytoplanktonic populations may occur if such an enrichment continues.
AN: 4275121
89 of 313
TI: Role of zooplankton in the cycling and reminerallzation of chemical materials in the Southern California Bight: California Basin Study: DOE (Department of Energy) west coast basin program: Progress report 4, (June 1987-June 1988).
AU: Small,-L.F.; Huh,-C.A.
AF: Oregon State Univ., Corvallis, (USA). Coll. of Oceanography
SO: 1988 54 pp
NT: NTIS Order No.: DE89002260/GAR. Contract FG05-85ER60340. Portions of this document are illegible in microfiche. 33 refs.
RN: DOE/ER/60340-4 (DOEER603404)
LA: English
ER: M (Marine)
AB: The overall objective of our research, within the structure of the DOE CaBS (California Basin Study) program, is to understand the transport pathways and mass balances of selected metabolically active and inactive chemical species in the Santa Monica/San Pedro Basins. One focus of our study is to examine the role of zooplankton and micronekton in the cycling and remineralization of chemical materials in the Southern California Bight, with particular reference to C, N and certain radionuclides and trace metals. A second focus is to examine these same radionuclides and trace metals in other reservoirs besides the zooplankton (i.e., in seawater, sediment trap material and bottom sediments). Knowledge of the rates, routes and reservoirs of these nuclides and metals should lead to a cogent model for these elements in Santa Monica /San Pedro Basins. Our zooplankton C and N data, in conjunction with primary production, microbiological and sediment flux data from colleagues in the program, should also lead ultimately to a model of C and N cycling in the basins (DBO).
AN: 4275952
90 of 313
TI: [Modelling of biogeochemical cycles of elements limiting phytoplancton production in Brest Roadsted]
OT: Modelisation des cycles biogeochimiques des elements limitant la production phytoplanctonique en rade de Brest
AU: Le-Pape,-O.
CA: Ecole Natl. Superieure d'Agronomie ENSAR, Rennes (France)
SO: Rennes-France Ecole-Nationale-Superieure-d'-Agronomie 1996 195 pp
NT: Order number: 961 Serial number: H36.
LA: French
ER: M (Marine)
AB: This study has been planned in order to analyse the response of phytoplankton stocks to increasing eutrophic conditions. A survey of the annual cycle of hydrographic properties, nutrients and chlorophyll a concentrations, and carbon uptake rates was firstly performed at four stations in 1993. Compared to the seventies, a doubled nitrate loading is now entering this ecosystem, which is related to increased agricultural activities on the drainage basins, while the geographical origin of the nitrate input has been modified. As a result of these anthropogenie modifications, summer averaged Si/N stoichiometric balance has decreased during the two last decades but, phytoplankton stocks have not increased. This study of the available data on this ecosystem point out on several ecological factors which have hindered eutrophication: the high hydrodynamic mixing with adjacent marine waters, caused by the macrotidal regime, induces important nutrients losses, temperature and mostly light limit primary production while Si and P high recycling maintain nitrogen limitation in this ecosystem. Then, conjunction of non anthropogenic limiting factors seems to explain the global stability of phytoplankton stocks. A box model, based on the horizontal tidal circulation, has been developed thanks to "ELISE", an ecological modelling software. This model has allowed us to quantify the influence of hydrodynamism, climatic conditions and biological factors on biogeochemical processes in this ecosystem, contributing to explain the good resistance of the Bay of Brest ecosystem to eutrophic conditions. It demonstrates that, in the Bay of Brest, tide-induced water exchanges are important enough to export massive winter nutrients stocks before the first bloom occurrence. The increasing grazing pressure during summer, mostly by benthic feeders, explains the occurrence of low phytoplankton stocks during the summer period. Conjunction of abiotic factors in spring and biotic factors in summer then explains the low productivity of this ecosystem during the productive period in regard to nitrogen input. So, data analysis and modelling approach coupling leads to improve the knowledge on the bay of Brest ecosystem: both the physical (hydrodynamic and climatic) and the biological (mostly grazing pressure) properties of this bay have prevented it from disturbances caused by high nitrogen loading from the watersheds and explain the steadiness of phytoplankton stocks in spite of increasing loading. Then, these results and the hypothetical simulations performed with the model allow us to say that, even if nitrogen inputs increase goes on, phytoplankton stocks will not increase in important proportions. Nevertheless, changes in the phytoplanktonic populations may occur if such an enrichnient goes on.
AN: 4281608
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TI: Upper ocean distribution of super(234)Th in the Northeast Pacific: Temporal variation and the role of colloids
AU: Huh,-Chih-An
AF: Inst. Earth Sci., Acad. Sinica, Taipei, Taiwan, ROC
SO: J.-Oceanogr. 1997 vol. 53, no. 5, pp. 481-488
LA: English
ER: M (Marine)
AB: Temporal variation in upper ocean distribution of super(234)Th between dissolved, colloidal, and particulate forms was observed at an open-ocean station in the Northeast Pacific. As a percentage of the total super(234)Th in the euphotic zone (0-100m), dissolved, colloidal, and particulate super(234)Th accounted for 78-91%, 5-12%, and 3-10%, respectively. The concentration of colloidal super(234)Th correlated positively with chlorophyll a and negatively with dissolved super(234)Th. A prominent feature of the water column profiles of colloidal and particulate super(234)Th is that the former was always higher than the latter above the permanent pycnocline whereas the opposite was true below the permanent pycnocline. The observations support the perception that the bulk of colloids in the upper ocean are organic-rich macromolecules produced by phytoplankton and they are the immediate phase removing dissolved super(234)Th from solution. The time integrated mean residence time in the euphotic zone is reversible reaction months for dissolved super(234)Th and similar to days for colloidal and particulate super(234)Th. The short residence time and organic nature of colloids suggest that, in addition to chemical scavenging of particle-reactive elements, colloids may also be responsible for a significant fraction of carbon export from the upper ocean.
AN: 4281362
92 of 313
TI: Response of benthic foraminifera to organic carbon accumulation rates in the Okinawa Trough
AU: Wahyudi; Minagawa,-Masao
AF: Grad. Sch. Environ. Earth Sci., Hokkaido Univ., Sapporo, Japan
SO: J.-Oceanogr. 1997 vol. 53, no. 5, pp. 411-420
LA: English
ER: M (Marine)
AB: The last glacial maximum in an Okinawa Trough sediment core is marked by high accumulation rate of organic carbon derived from surface water productivity. This coincides with increasing individual numbers of two benthic foraminifera, infaunal species Uvigerina peregrina and epifaunal Cibicidoides wuellerstorfi, and great delta super(13)C difference between both species. The increased abundances of U. peregrina and C. wuellerstorfi during the last glacial episode are interpreted as the result of a higher flux of organic matter (food) reaching the sediment surface as a consequence of increased surface water productivity. The good correlation between differences in delta super(13)C values of U. peregrina and C. wuellerstorfi and the organic carbon accumulation rates suggests that the greater the flux of organic matter reaching the sea floor, the more super(13)C depleted CO sub(2) was released by organic matter decomposing within the sediment. On the other hand, when the flux of organic matter decreased, the super(13)C depleted CO sub(2) within the sediment also decreased. We suggest that this delta super(13)C difference can be utilized as an indicator of organic matter flux changes. These findings provide new evidence for the paleoceanography of the Okinawa Trough in the East China Sea.
AN: 4281356
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TI: Dissolved and particulate organic carbon in the western Mediterranean Sea
AU: Cauwet,-G.; Miller,-A.; Brasse,-S.; Fengler,-G.; Mantoura,-R.F.C.; Spitzy,-A.
AF: Cent. Natl. de la Recherche Scientifique, URA 117 and GDR 909, Observatoire Oceanologique, Lab. Arago, BP 44, 66651 Banyuls sur Mer, France
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 3-4, pp. 769-779
NT: Special issue: EROS 2000.
LA: English
ER: M (Marine)
AB: Particulate and dissolved organic carbon data, collected during five years in the western basin of the Mediterranean Sea, are presented and discussed. The influence of the river inputs is identified by higher surface DOC concentrations. Particulate carbon is mainly correlated with primary production in surface waters, and exhibits a seasonal variability. In surface waters, DOC is in higher concentration compared to deep water, in direct relation with particulate carbon, i.e. with production. Accumulation of DOC occurs during summer and disappears rapidly after September. Sections drawn along transects show that different water masses are identified, with characteristic DOC concentrations. Mechanisms of carbon cycling are identified, as are the general characteristics of the northwest Mediterranean Sea concerning organic carbon distribution.
AN: 4280131
94 of 313
TI: The relationship between ammonia excretion and GDH activity in marine zooplankton
AU: Hernandez-Leon,-S.; Torres,-S.
AF: Fac. de Cienc. del Mar, Univ. de Las Palmas de G.C., PO Box 550, Las Palmas de G.C., Canary Islands, Spain
SO: J.-PLANKTON-RES. 1997 vol. 19, no. 5, pp. 587-601
LA: English
ER: M (Marine)
AB: The relationship between the ammonia excretion rate and glutamate dehydrogenase (GDH) activity was studied in marine zooplankton over the course of a bloom and in different size classes (100-200, 200-500 and 500-1000 mu m). A weak correlation between GDH activity and ammonia excretion rate was observed when all data were pooled. Better relationships between the parameters were obtained by taking into account the substrate being metabolized, as deduced from the experimentally determined O/NH sub(4) ratio. There was also a positive correlation between the GDH/NH sub(4) and O/NH sub(4) ratios, suggesting that the former ratio was lower when the metabolic substrate being metabolized contained a high level of nitrogen. High GDH/NH sub(4) and high standard deviations were found when the in situ temperatures were low, while the ratio and standard deviations decreased at higher temperatures. Temperature probably had an indirect effect as a consequence of a better availability of nitrogen in the food when mixing took place in the water column. Differences in the GDH /ammonia ratio were also observed for different size fractions, largely because small animals had higher ammonia excretion rates. The composition of the metabolic substrate affected the observed GDH/NH sub(4) ratios because it led to variations in cellular glutamate concentrations, while enzyme activities were measured at maximal rates (V sub(max)). It is suggested that this methodological limitation is probably the most important factor in determining the relationship between enzymatic activities and metabolic rates.
AN: 4280115
95 of 313
TI: The need for mass balance and feedback in the geochemical carbon cycle
AU: Berner,-R.A.; Caldeira,-K.
AF: Dep. Geol. and Geophysics, Yale Univ., New Haven, CT 06520-8109, USA
SO: GEOLOGY 1997 vol. 25, no. 10, pp. 955-956
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: On a multimillion-year time scale, the level of atmospheric carbon dioxide, and consequently the atmospheric greenhouse effect, is affected largely by the geochemical, or long-term, carbon cycle. This cycle involves the exchange of carbon dioxide between rocks, on the one hand, and the surficial reservoir, consisting of the combined atmosphere, oceans, biosphere, plus soils, on the other. Carbon dioxide is exchanged with the surficial system via weathering of silicates and organic matter on the continents, the burial of carbonates (derived from silicate weathering) and organic matter in sediments, and the thermal breakdown of carbonates and organic matter at depth. It has been suggest that in the geochemical carbon cycle there is no necessity for a close balance between atmospheric inputs and outputs of CO sub(2), and therefore no need for a strongly coupled feedback to stabilize CO sub(2) level in the atmosphere. On the basis of their study of the chemistry of major rivers, Edmond et al. concluded that climate has little effect on global weathering rate and criticized the idea that long-term stabilization of CO sub(2) and climate comes about by increased chemical weathering rate that accompanies global greenhouse warming. In place of a climate-weathering feedback, Edmond et al. and Bickle assumed that increases in global degassing are eventually matched by increases in CO sub(2) uptake via enhanced weathering accompanying mountain uplift. We show here that in this case, atmospheric CO sub(2) would vary untenably as a result of large imbalances in the carbon cycle.
AN: 4279687
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TI: Boundary flux measurements in the coastal ocean
AU: Brown,-W.S.
AF: Univ. New Hampshire, Durham, NH, USA
SO: The-Global-Coastal-Ocean:-Processes-and-Methods Brink,-K.H.;Robinson,-A.R.-eds. 605-Third-Avenue John-Wiley-and-Sons,-Inc. vol. 10 617 pp
ST: The-Sea:-Ideas-and-Observations-on-Progress-in-the-Study-of-the-Seas 1998 vol. 10
LA: English
ER: M (Marine)
AB: As we move rapidly toward operational use of regional data assimilation models for monitoring and prediction in the coastal ocean, appropriate observational systems will have to be implemented. Various combinations of measurements and models will be necessary to both force and constrain the models. There are two basic ways to approach the problem of combining observations and regional models of the coastal ocean. One is to apply "observed" boundary fluxes to the open boundaries of the model of choice. The other is to assimilate observations into the interior of the model using statistically and dynamically consistent methodology. The boundary fluxes then become part of the solution. In this chapter the former approach is emphasized while brief comment is made of the latter approach. In particular we review some of the methods presently used for providing various boundary fluxes through the surface, bottom and lateral boundaries of typical coastal ocean domains. Although any number of other coastal domains could serve our purposes here, we consider methods for measuring boundary fluxes as they apply to the Gulf of Maine region. Geographically, the Gulf of Maine is a marginal sea embedded in the northeast American continental shelf. Georges and Browns Banks effectively buffer the interior gulf from the deep ocean. This and adjacent regions contain a variety of coastal ocean environments, including wide shelves, narrow shelves, shallow banks, deep basins, and regions of both complex and smooth bathymetry.
AN: 4279512
97 of 313
TI: Evaluation and comparison of the global carbon cycle in the coastal zone and in the open ocean
AU: Wollast,-R.
AF: Univ. Brussels
SO: The-Global-Coastal-Ocean:-Processes-and-Methods Brink,-K.H.;Robinson,-A.R.-eds. 605-Third-Avenue John-Wiley-and-Sons,-Inc. vol. 10 617 pp
ST: The-Sea:-Ideas-and-Observations-on-Progress-in-the-Study-of-the-Seas 1998 vol. 10
LA: English
ER: M (Marine)
AB: Our knowledge of the carbon cycle on a global scale has improved greatly in the past decades. However, the role of the coastal zone in sequestering organic and inorganic carbon, as well as the importance of continental margins in the exchange of carbon with the open ocean, remain controversial. There are contrasting differences in the physical, chemical and biological properties between the coastal zone and the open ocean, leading to marked gradients that influence strongly the exchanges between the two systems. The fluxes at the ocean margins, linked to these horizontal gradients, may play a significant role in the elemental biogeochemical cycles in the oceans a local or global scale. Our knowledge is, however, presently insufficient for an understanding of the past, present and future behavior of these cycles. The aim of this chapter is to evaluate critically the existing data concerning the organic and inorganic carbon cycle in the marine system, with emphasis on the difference between the coastal zone and the open ocean.
AN: 4279374
98 of 313
TI: The importance of organic detritus in lotic ecosystems: Aspects of trophic interactions
AU: Chamier,-A.-C.
AF: Achandunie House, Ardoss by Alness, Ross and Cromarty IV17 OYB, UK
SO: Freshwat.-Forum 1997 vol. 9, pp. 14-24
LA: English
ER: F (Freshwater)
AB: Very little research has been carried out on detrital energetics and pathways in lotic ecosystems. Most investigations have concentrated on the degradation of allochthonous plant litter by fungi, with a glance at heterotrophic bacteria associated with decaying litter. In this short review, the author describes what is known of the detrition of plant litter in lotic waters, which results from the degradative activities of colonising saprophytic fungi and bacteria, and goes on to relate this process to those invertebrates that consume coarse and/or fine particulate detritus, or dissolved organic matter that aggregates into colloidal exopolymer particles. It is clear that many of the key processes involved in the relationships between the physical, chemical, biotic and biochemical elements present in running waters are very complex and poorly understood. Those few aspects for which there are reliable models with predictive power have resulted from data collections made over periods of 20 years or more. Comprehensive research of single catchments would provide a fine opportunity to collect data over a long period.
AN: 4271265
99 of 313
TI: A technique for the in situ assessment of the vertical nitrogen flux caused by the diel vertical migration of zooplankton
AU: Hays,-G.C.; Harris,-R.P.; Head,-R.N.; Kennedy,-H.
AF: Sch. Biol. Sci., Univ. Wales Swansea, Singleton Park, Swansea SA2 8PP, UK
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 6, pp. 1085-1089
LA: English
ER: M (Marine)
AB: It is argued that if herbivorous zooplankton exhibiting diel vertical migration generally feed only above the thermocline at night, but continue to excrete during the day when they are below the thermocline, then there should be a diel variation in their mean body nitrogen content. Thus measurement of the body nitrogen content of migrating zooplankton at different times of the day may provide a technique for the in situ assessment of the rate at which they remove nitrogen from the surface mixed layer. We show that if the inter-individual variation in body nitrogen content is high and sample size is low, then detection of the predicted diel change will tend to be obscured. However, in a simple laboratory experiment, a significant reduction in the mean body nitrogen content of the copepod Calanus helgolandicus was found between fed individuals (mean 12.91 mu g N, n = 42, SD = 1.63) and those starved for 18 h (11.89 mu g N, n = 30, SD = 1.29; t-test, t sub(69) = 2.92, P= 0.0047), suggesting that the technique may be applied in the field.
AN: 4266501
100 of 313
TI: Eddy-induced nutrient supply and new production in the Sargasso Sea
AU: McGillicuddy,-D.J.,Jr.; Robinson,-A.R.
AF: Dep. Applied Ocean Phys. and Eng., Woods Hole Oceanographic Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 8, pp. 1427-1450
LA: English
ER: M (Marine)
AB: A limited area, eddy resolving coupled physical and biological model is used to examine the role of mesoscale dynamical processes in nutrient cycling in the Sargasso Sea. Upwelling due to the formation of cyclonic eddies and their intensification caused by interaction with surrounding mesoscale features causes spatially and temporally intermittent fluxes of nitrate into the euphotic zone. The annual flux resulting from this eddy upwelling process is of the order of 0.5 mol N/m super(2)/year, which is sufficient to sustain a rate of new primary production that is consistent with estimates for this region derived from budgets of oxygen and other dissolved gases.
AN: 4260788
101 of 313
TI: Bacterial abundance and production in different water masses around South Island, New Zealand
AU: Smith,-R.; Hall,-J.
AF: Natl. Inst. Water & Atmos. Res. Ltd., P.O. Box 8602, Christchurch, New Zealand
SO: N.-Z.-J.-MAR.-FRESHWAT.-RES. 1997 vol. 31, no. 4, pp. 515-524
LA: English
ER: M (Marine)
AB: Bacterial numbers and production were measured in the upper water column in the winter and spring of 1993 in five water masses surrounding the South Island of New Zealand. Average bacterial numbers and production were found to be higher in spring (8.5 x 10 super(5) cells ml super(-1) and 0.20 mg m super(3) h super(-1), respectively) than winter (5.5 x 10 super(5) cells ml super(-1) and 0.05 mg C m super(3) h super(-1) respectively). Bacterial production was strongly correlated with chlorophyll a and primary production (P < 0.001) in spring but not in winter. Spring bacterial production and at 10 m depth averaged across 28 stations was 23% of primary production, and with a growth efficiency of 40%, may have consumed up to 57% of primary production. Bacterial biomass was greater than phytoplankton biomass for 75% of the 10 m depth comparisons during winter sampling and 44% during the spring sampling. The bacterial biomass was found to represent 24.6-33.5% of the nitrogen in particulate organic matter (<200 mu m) supporting the concept that in New Zealand oceanic water masses bacteria are of significant biogeochemical importance.
AN: 4260787
102 of 313
TI: The importance of microbial Mn oxidation in the upper ocean: A comparison of the Sargasso Sea and equatorial Pacific
AU: Moffett,-J.W.
AF: Dep. Mar. Chem. and Geochemistry, Woods Hole Oceanographic Inst., Woods Hole, MA 02543-1543, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 8, pp. 1277-1291
LA: English
ER: M (Marine)
AB: The processes responsible for Mn uptake onto suspended particles in the upper water column were studied in the equatorial Pacific and in the Sargasso Sea at the Bermuda Atlantic Time Series (BATS) Station. Oxidation was followed by incubating freshly collected seawater with super(54)Mn and using a combination of procedures developed by others to distinguish oxidation from adsorption and biological from non-biological processes. Results in the Sargasso Sea indicate that oxidation is the principal pathway for the formation of particulate Mn throughout the year, in good agreement with the findings of earlier workers. These data, combined with earlier studies from diverse environments, suggest that microbial Mn oxidation is a ubiquitous process in oxygenated marine environments. However, in the equatorial Pacific we detected no microbial oxidation above 175 m. Formation of particulate super(54)Mn occurred and was inhibited in the presence of azide, indicating a biological process, but the particulate Mn could not be dissolved by the addition of ascorbate, an important criterion, as Mn oxides are readily reduced at seawater pH by ascorbate. In the Pacific, the non-oxidative, biologically mediated uptake was enhanced by light, possibly because of uptake by phytoplankton, as Mn is an essential micronutrient. By contrast, oxidative biological uptake in the Sargasso Sea was inhibited by light, in agreement with earlier work. The results indicate that the geochemical cycling of Mn is different in the two environments, presumably reflecting aspects of the ecology of Mn oxidizing bacteria that are not understood. These findings suggest that it is premature to generalize about the relative importance of oxidative vs. non-oxidative scavenging of Mn from the euphotic zone in the open ocean without additional data.
AN: 4260772
103 of 313
TI: Phosphate mobilization in iron-rich anaerobic sediments: Microbial Fe(III) oxide reduction versus iron-sulfide formation
AU: Roden,-E.E.; Edmonds,-J.W.
AF: Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487-0206, USA
SO: Arch.-Hydrobiol. 1997 vol. 139, no. 3, pp. 347-378
NT: Inc. bibliogr.: 72 refs.
LA: English
ER: F (Freshwater)
AB: Mechanisms of phosphate (PO sub(4) super(3-)) mobilization and retention were examined in iron-rich anaerobic freshwater wetland, lake, and coastal marine sediments. Direct microbial Fe(III) oxide reduction solubilized only 3-25% of initial solid-phase PO sub(4) super(3-) during sulfate-free sediment incubation experiments. Experiments with reduced, non-sulfidic solid-phase Fe(II)-rich sediment demonstrated PO sub(4) super(3-) sorption by the solid-phase, and chemical equilibrium calculations indicated that conditions were favorable for precipitation of Fe(II)-PO sub(4) minerals [e.g. Fe sub(3)(PO sub(4)) sub(2)] in such sediments. These results suggested that much of the PO sub(4) super(3-) released from Fe(III) oxides during microbial Fe(III) reduction was captured by solid-phase reduced iron compounds (Fe(II) hydroxide-PO sub(4) complexes and/or Fe(II)-PO sub(4) minerals). Enhanced liberation of PO sub(4) super(3-) to sediment porewaters (33-100 % of initial solid-phase PO sub(4) super(3-)) occurred during anaerobic incubation in the presence of abundant sulfate and was directly corre- lated with sulfate reduction and iron-sulfide mineral formation. Incubation of PO sub(4) super(3-)- amended sediment with different amounts of sulfate demonstrated a linear correlation between PO sub(4) super(3-) release and sulfate reduction. Release of PO sub(4) super(3-) to sediment porewaters during decomposition of fresh organic matter (freeze-dried cyanobacteria) was more extensive in sulfate-amended (67% of added organic P) than in sulfate-free sediment (17% of added organic P), and the ratio of dissolved PO sub(4) super(3-) released to organic carbon oxidized was seven-fold higher in sulfate-amended sediment despite a common level of overall organic C and P mineralization in the two treatments. Our results demonstrate that iron-rich anaerobic sediments can immobilize substantial amounts of PO sub(4) super(3-) under Fe(III) oxide-reducing conditions, but that extensive PO sub(4) super(3-) release will take place if sediment Fe compounds are converted to iron-sulfides via bacterial sulfate reduction.
AN: 4257827
104 of 313
TI: Foraminiferal proxies: Constraints on their use in high latitude paleoceanography
OT: Zur Palaeoozeanographie hoher Breiten: Stellvertreterdaten aus Foraminiferen
AU: Mackensen,-A.
CA: Bremen Univ., Bremen (FRG), Fachber. Geowissenschaften
SO: Ber.-Polarforsch.-Rep.-Polar-Res. 1997 no. 243, 146 pp
NT: Incl. 18 pages refs.
LA: German
ER: M (Marine)
AB: This compilation on the reliability and trustworthiness of benthic foraminiferal proxies is based on Recent and Late Quaternary sample material from the polar oceans, collected during the last 15 years from the sea floors of the Arctic Ocean, the Norwegian/Greenland Seas and the North Atlantic Ocean, as well as from the Weddell Sea and the South Atlantic Ocean. In addition, Tertiary sample material from the Antarctic sites of the Ocean Drilling Program is considered. To check proxies against their Recent analogue foraminiferal faunas from surface sediment samples were investigated in relationship to their particular biogeochemical environment. First of all semi-quantitative and qualitative proxies for new production, seasonality, bottom water ventilation, current velocities, and water depth were discussed, all of which derived by paleontological methods from standing crop data, species composition and microhabitat preferences of benthic foraminiferal faunas. Then the author discusses proxies for nutrient content, temperature and salinity of water masses, all of which derived by geochemical methods from the stable isotopic composition and trace element contents of calcareous foraminiferal tests. As a conclusion, paleontological proxies can be quantitatively interpreted just in a broad way, i.e. only under consideration and with knowledge of ecologically limiting threshold values.
AN: 4257549
105 of 313
TI: Primary production, calcification, and air-sea CO sub(2) fluxes of a macroalgal-dominated coral reef community (Moorea, French Polynesia)
AU: Gattuso,-J.-P.; Payri,-C.E.; Pichon,-M.; Delesalle,-B.; Frankignoulle,-M.
AF: Observatoire Oceanologique Europeen, Ave. Saint-Martin, MC-98000 Monaco, Principality of Monaco
SO: J.-PHYCOL. 1997 vol. 33, no. 5, pp. 729-738
LA: English
ER: M (Marine)
AB: Community metabolism and air-sea carbon dioxide (CO sub(2)) fluxes were investigated in July 1992 on a fringing reef at Moorea (French Polynesia). The benthic community was dominated by macroalgae (85% substratum cover) and comprised of Phaeophyceae Padina tenuis (Bory), Turbinaria ornata (Turner) J. Agardh, and Hydroclathrus clathratus Bory (Howe); Chlorophyta Halimeda incrassata f. ovata J. Agardh (Howe); and Ventricaria ventricosa J. Agardh (Olsen et West), as well as several Rhodophyta (Actinotrichia fragilis Forskaal (Borgesen) and several species of encrusting coralline algae). Algal biomass was 171 g dry weight times m super(-2). Community gross production (P sub(g)), respiration (R), and net calcification (G) were measured in an open-top enclosure. P sub(g) and R were respectively 248 and 240 mmol CO sub(2)/m super(2)/d, and there was a slight net dissolution of CaCO sub(3) (0.8 mmol/m super(2)/d). This site was a sink for atmospheric CO sub(2) (10 plus or minus 4 mmol CO sub(2)/m super(2)/d), and the analysis of data from the literature suggests that this is a general feature of algal-dominated reefs. Measurement of air-sea CO sub(2) fluxes in open water close to the enclosure demonstrated that changes in small-scale hydrodynamics can lead to misleading conclusions. Net CO sub(2) evasion to the atmosphere was measured on the fringing reef due to changes in the current pattern that drove water from the barrier reef (a CO sub(2) source) to the study site.
AN: 4247872
106 of 313
TI: Methane and carbon dioxide dynamics in Typha latifolia (L.) wetlands in central New York state
AU: Yavitt,-J.B.
AF: Dep. Nat. Resour., Fernow Hall, Cornell Univ., Ithaca, NY 14853, USA
SO: WETLANDS 1997 vol. 17, no. 3, pp. 394-406
LA: English
ER: F (Freshwater)
AB: I examined differences in the biogeochemical cycles of CH sub(4) and CO sub(2) (fluxes, concentrations, production, CH sub(4) oxidation) in Typha latifolia wetlands on silty clay sediment versus organic peat soil in central New York state to determine whether variation in the amount of organic matter in sediment or soil, or plant production on sites with different organic matter content, affected variation in CH sub(4) and CO sub(2). I found very high temporal variation in CH sub(4) within each site, precluding the detection of variation in CH sub(4) as a function of sediment or soil organic matter content. In 1994, CH sub(4) efflux from two peat sites to the atmosphere averaged 7 and 87 nmol m super(-2) s super(-1) compared to 89 and 408 nmol m super(-2) s super(-1) for two sediment sites. Mean CO sub(2) efflux from the peat sites was 0.40 and 1.51 mu mol m super(-2) s super(-1) compared to 1.02 and 1.65 mu mol m super(-2) s super(-1) for the sediment sites. I assessed the role of plant production by experimentally removing T. latifolia shoots from small plots: this lowered CH sub(4) efflux from the sediment site by 85%, suggesting that plants foster CH sub(4) production in low organic matter sediment, but CH sub(4) efflux was 14-times greater following shoot removal on one peat site. Shoot removal had no effect on CO sub(2) efflux. Variations in temperature, dissolved organic carbon, and pCH sub(4) in sediment or soil porewater explained the variation in CH sub(4) efflux among the four study sites, whereas variation in net primary production explained the variation in CO sub(2) efflux.
AN: 4228923
107 of 313
TI: Seasonal variation of CDOM and DOC in the Middle Atlantic Bight: Terrestrial inputs and photooxidation
AU: Vodacek,-A.; Blough,-N.V.; DeGrandpre,-M.D.; Peltzer,-E.T.; Nelson,-R.K.
AF: Dep. Chem. and Biochem., Univ. Maryland, Coll. Park, MD 20742, USA
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 4, pp. 674-686
LA: English
ER: M (Marine)
AB: Extensive surveys of the fluorescence and absorption of chromophore-containing dissolved organic matter (CDOM), dissolved organic C (DOC) concentration, chlorophyll fluorescence, and salinity were performed during August and November 1993 and March and April 1994 along a cruise line extending from the mouth of Delaware Bay southeast to the Sargasso Sea. With shallow stratification in August, photobleaching dramatically altered the optical properties of the surface waters, with similar to 70% of the CDOM absorption and fluorescence lost through photooxidation in the waters at the outer shelf. S, the slope of the log-linearized absorption spectrum of CDOM, increased offshore and seemed to increase with photodegradation. The increase in S combined with the seasonal variation in the relationship between Chl and CDOM underscores the difficulty in developing algorithms to predict Chl concentrations in turbid coastal waters with ocean color data. Despite the photooxidation of CDOM, the seasonal variation in the CDOM fluorescence-absorption relationship and fluorescence quantum yields was <15%. When using appropriate methods, the airborne lidar approach for remote determination of CDOM absorption coefficients seems to be a very robust technique. The photooxidation of CDOM in August also affected the relationship between CDOM and DOC concentration in the surface waters, although for the rest of the year the relationship was reasonably linear. The results of a simple model suggest similar to 10% of the DOC in the mixed layer was directly converted photochemically to dissolved inorganic C (DIC).
AN: 4228354
108 of 313
TI: Microbial mineralization of organic carbon and dissolution of inorganic carbon from mussel shells (Mytilus edulis)
AU: Knauth-Koehler,-K.; Albers,-B.P.; Krumbein,-W.E.
AF: Carl von Ossietzky-Universitaet Oldenburg, Institut fuer Chemie und Biologie des Meeres (ICBM), Meeresstation, Schleusenstrasse 1, D-26382 Wilhelmshaven, FRG
SO: Senckenb.-Marit. 1996 vol. 26, no. 3-6, pp. 157-165
LA: English
ER: M (Marine)
AB: Bacteria in marine environments grow on living organisms as well as on surfaces of organic and inorganic detrital particles, where essential nutrients are concentrated. Using electron micrographs, this study of the influence of microorganisms on the decay of biogenic organic and inorganic carbon compounds has revealed a dense microflora adsorbing to mussel shells. Investigations of bacterial populations isolated from shells of Mytilus edulis demonstrated the use of organic matter from mussel shells as nutrient. This was also proved by changes in the super(13)C/ super(12)C ratios of the mussel shells. It can be assumed that the decomposition of the periostracum impairs the crystallite structure of the mussel carbonate layers and thus initiates the microbial destruction of the biogenic carbonate. In laboratory experiments, it was shown that the bacterial populations produce organic acids under aerobic as well as under anaerobic conditions causing a shift in carbonate equilibrium which results in the dissolution of CaCO sub(3). The decomposition of organic mussel shell matrices and the high carbonate dissolution rates by bacterial populations isolated from mussel shells lead to the assumption that a specifically adapted epibiotic mussel microflora exists.
AN: 4212793
109 of 313
TI: Deep water particle flux in the Canary Island region: Seasonal trends in relation to long-term satellite derived pigment data and lateral sources
AU: Neuer,-S.; Ratmeyer,-V.; Davenport,-R.; Fischer,-G.; Wefer,-G.
AF: FB 5 Geosciences, Univ. Bremen, Klagenfurterstrasse, 28395 Bremen, Germany
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 8, pp. 1451-1466
LA: English
ER: M (Marine)
AB: We present a 3 year record of deep water particle flux at the recently initiated ESTOC (European Station for Time-series in the Ocean, Canary Islands) located in the eastern subtropical North Atlantic gyre. Particle flux was highly seasonal, with flux maxima occurring in late winter-early spring. A comparison with historic CZCS (Coastal Zone Colour Scanner) data shows that these flux maxima occurred about 1 month after maximum chlorophyll was observed in surface waters in a presumed primary source region 100 km x 100 km northeast of the trap location. The main components of the particles collected with the traps were mineral particles and carbonate, both correlating strongly with organic matter sedimentation. Mineral particles in the sinking matter are indicative of the high aeolian input from the African desert regions. Comparing particle fluxes at 1 km and 3 km depth, we find that particle sedimentation increased substantially with depth. Yearly organic carbon sedimentation was 0.6 g m super(-2) at 1 km depth compared with 0.8 g m super(-2) at 3 km. We hypothesize that higher phytoplankton biomass observed further north could be a source of laterally advecting particles that interact with fast sinking particles originating from the primary source region. This hypothesis is also supported by the differences in size distribution of lithogenic matter found at the two trap depths.
AN: 4241088
110 of 313
TI: Particle flux in deep seas: Regional characteristics and temporal variability
AU: Lampitt,-R.S.; Antia,-A.N.
AF: Southampton Oceanogr. Cent., Empress Dock, Southampton SO14 ZH, UK
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 8, pp. 1377-1403
LA: English
ER: M (Marine)
AB: Particle flux data have been collated from the literature representing most areas of the open ocean to determine regional trends in deep water flux and its seasonal variability. Organic carbon flux data normalised to a depth of 2000 m exhibits a range of an order of magnitude in areas outside the polar domains (0.38 to 4.2 g/m super(2) /y). In polar regions the range is wider (0.01-5.9 g/m super(2)/y). Latitudinal trends are not apparent for most components of the flux although calcite flux exhibits a poleward decrease. Limited data from polar regions show fluxes of opaline silica not significantly higher than elsewhere. The variability of flux over annual cycles was calculated and expressed as a Flux Stability Index (FSI) and the relationship between this and vertical flux of material examined. Somewhat surprisingly there is no significant relationship between FSI and fluxes of dry mass, organic carbon, inorganic carbon or opaline silica. At each site, net annual primary production was determined using published satellite derived estimates. There is a negative but weak relationship between FSI and the proportion of primary production exported to 2000 m (e sub(2000) ratio). The most variable of the nonpolar environments export to 2000 m about twice as much of the primary production as the most stable ones. Polar environments have very low e sub(2000) ratios with no apparent relationship to FSI. At primary production levels below 200 g C/m super(2)/y there is a positive correlation between production and organic carbon flux at 2000 m but above this level, flux remains constant at about 3.5g C/m super(2)/y. A curve derived to describe this relationship was applied to estimates of annual primary production in each of 34 of the open ocean biogeochemical provinces proposed by Longhurst et al. (1995). Globally, open ocean flux of organic carbon at 2000 m is 0.34 Gt/yr which is 1% of the total net primary production in these regions. This flux is nearly equally divided between the Atlantic, Pacific and Southern Oceans. The Indian and Arctic oceans between them only contribute 5% to the total. The eight planktonic climatological categories proposed by Longhurst (1995) provide a most useful means of examining the data on flux and its variability. A characteristic level of FSI was found in each category with highest levels in the tropics and lowest levels in the Antarctic. There is also a characteristic level of export ratio in each category with the highest in monsoonal environments (1.7%) and the lowest in Antarctica (0.1%).
AN: 4241086
111 of 313
TI: Oceanic dissolved organic carbon is the main sink of atmospheric CO sub(2)
AU: Gorshkov,-V.G.
AF: Petersburg Nuclear Phys. Inst., Gatchina, 188350 Leningrad Dist., Russia
SO: WORLD-RESOUR.-REV. 1997 vol. 9, no. 2, pp. 153-169
LA: English
ER: M (Marine)
AB: Production of the dissolved organic carbon (DOC) in the equilibrium preindustrial state constituted about 0.2% of the oceanic net primary production. Ocean biota negatively feedbacks to the CO sub(2) concentration change in the environment. Modern share of DOC production in the oceanic net primary production has increased nearly twenty-fold during the industrial era. Rate of DOC destruction has remained unchanged. Rate of DOC mass increase is about 2 Gt C/year now and coincides with land use estimation of carbon release by terrestrial biota. This coincidence resolves the problem of "missing carbon sink". All the results were obtained from data on distribution of prebomb and postbomb super(14)C in the ocean. Surface DOC in equilibrium state had a negligibly small fraction with decadal turnover time. The observed increase of radiocarbon in surface DOC is a result of broken equilibrium state and DOC mass increase during the whole industrial era. The obtained results agree with modern data on atmospheric O sub(2)/N sub(2) ratio change.
AN: 4239784
112 of 313
TI: [Chromium in marine environment]
OT: Le chrome en milieu marin
AU: Chiffoleau,-J.F.
SO: Reperes-Ocean Plouzane-France IFREMER 1994 no. 8, 43 pp
LA: French
ER: M (Marine)
AB: This document constitutes a synthesis of current knowledge on the chromium biogeochemical cycle. The natural and anthropogenic sources are evaluated, the fluxes between the various geochemical compartments are assessed, with special attention to the riverine and atmospheric inputs to the marine environment. Chromium levels in these compartments are described and show in several areas a very high contamination of marine organisms. Due to the important toxicity of this element, further investigations are absolutely required to better understand its behaviour in the marine environment.
AN: 4236621
113 of 313
TI: Surface activation of manganese oxide electrode for oxygen evolution from seawater
AU: Izumiya,-K.; Akiyama,-E.; Habazaki,-H.; Kawashima,-A.; Asami,-K.; Hashimoto,-K.; Kumagai,-N.
AF: Inst. for Materials Res., Tohoku Univ., Sendai 980-77, Japan
SO: J.-APPL.-ELECTROCHEM. 1997 vol. 27, no. 12, pp. 1362-1368
LA: English
ER: M (Marine)
AB: Utilizing the fact that the equilibrium potential of oxygen evolution is lower than that of chlorine evolution, oxygen evolution in seawater electrolysis was enhanced by decreasing the polarization potential under galvanostatic conditions through increasing the effective surface area of manganese oxide electrodes. Electrodes were prepared by a thermal decomposition method. IrO sub(2)-coated titanium (IrO sub(2)/Ti electrode) was used as the substrate on which manganese oxide was coated (MnO sub(X)/IrO sub(2)/Ti electrode). Subsequently, oxide mixtures of manganese and zinc were coated (MnO sub(X)-ZnO/MnO sub(X)/IrO sub(2)/Ti electrode). The effective surface area of the MnO sub(X)-ZnO/MnO sub(X)/IrO sub(2)/Ti electrodes was increased by selective dissolution of zinc (leaching) into hot 6 M KOH. The oxygen evolution efficiency of the MnO sub(X)/IrO sub(2)/Ti electrode was 68-70%. Leaching of zinc from the MnO sub(X)-ZnO/MnO sub(X)/IrO sub(2)/Ti electrodes with 25 mol% or less zinc led to a significant increase in the oxygen evolution efficiency. The maximum efficiency attained was 86% after leaching of zinc from the MnO sub(X)-25 mol%ZnO/MnO sub(X) /IrO sub(2)/Ti electrode. However, large amounts of zinc addition, such as 40 mol% or more are detrimental because of a decrease in the oxygen evolution efficiency. This is due to the formation of a double oxide, ZnMnO sub(3), which is hardly dissolved in hot 6 M KOH.
AN: 4229740
114 of 313
TI: Short-term effects of salinity reduction and drainage on salt-marsh biogeochemical cycling and Spartina (cordgrass) production
AU: Portnoy,-J.W.; Valiela,-I.
AF: United States Geol. Surv., Cape Cod Natl. Seashore, 99 Marconi Rd., Wellfleet, MA 02667, USA
SO: ESTUARIES 1997 vol. 20, no. 3, pp. 569-578
LA: English
ER: B (Brackish)
AB: To assess the biogeochemical effects of tidal restrictions on salt-marsh sulfur cycling and plant growth, cores of short-form Spartina alterniflora peat were desalinated and kept either waterlogged or drained in greenhouse microcosms. Changes in net Spartina production, and porewater and solid phase chemistry of treated cores were compared to natural conditions in the field collection site over a 21-mo period. Net production among treatments increased significantly in drained and waterlogged peat compared to field conditions during the first growing season. Constantly high sulfide in waterlogged cores accompanied reduced plant growth. Aeration invigorated growth in drained cores but led to oxidization of sulfide minerals and to lowered pH. During the second growing season, growth declined in the drained treatment, probably because of acidification and decreased dissolved inorganic nitrogen. Results are pertinent to the success of current wetland protection and restoration activities in the coastal zone.
AN: 4228948
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TI: Biomass and productivity of tropical macroalgae on three nearshore fringing reefs in the central Great Barrier Reef, Australia
AU: Schaffelke,-B.; Klumpp,-D.W.
AF: Australian Inst. Mar. Sci., PMB #3, Townsville 4810, Australia
SO: BOT.-MAR. 1997 vol. 40, no. 5, pp. 373-383
LA: English
ER: M (Marine)
AB: Recently, concerns about human disturbance on coral reef communities have focused attention on macroalgae of nearshore fringing coral reefs of the Great Barrier Reef, Australia (GBR). However, the scarcity of baseline information makes it difficult to establish whether nearshore reef communities in the central GBR are perturbed or in a 'natural' state. This study provides data on biomass and productivity of nearshore reef macroalgae to serve as background information for the detection of future community changes. Over a period of 15 months, we estimated: i) biomass of conspicuous macroalgae in transects at three nearshore fringing reefs and ii) in situ net growth rates and net production of Sargassum baccularia. In summer, biomass was significantly dominated by large Fucales, especially S. baccularia (up to 200 g ash free dry weight m super(-2)). Ephemeral algae (species of Padina, Hydroclathrus, Colpomenia, Chnoospora, Laurencia) were most abundant in austral spring (up to 40 g AFDW m super(-2)). Maximum growth rates of S. baccularia of 3-4% day super(-1) (entire thalli) occurred during the summer, preceding the reproductive period. Subsequent shedding of lateral branches resulted in negative growth rates during autumn/winter. In situ growth of excised shoots showed seasonal patterns comparable to entire thalli, except that growth rates were always positive. Biomass specific net production of excised shoots was significantly higher from spring to autumn than during winter. Areal productivity of S. baccularia had a significant maximum of 3 g C m super(-2) day super(-1) in spring, a value comparable to the productivity of coral-reef epilithic algal communities or temperate kelp forests. The high standing biomass, high productivity and a presumably rapid turnover of biomass via detrital pathways suggest that fucoid macroalgae are important contributors to the stock of organic compounds on these nearshore reefs.
AN: 4228939
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TI: The dissolved silica budget as a constraint on the meridional overturning circulation of the Indian Ocean
AU: Robbins,-P.E.; Toole,-J.M.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 5, pp. 879-906
LA: English
ER: M (Marine)
AB: The geostrophic circulation at 32 degree S in the Indian Ocean, based on hydrographic data collected in 1987 on the R.R.S. Charles Darwin, is re-examined with the inclusion of the advective flux of dissolved silica. Consideration of the physical mechanisms of silica transport at 32 degree S in conjunction with the silica budget of the Indian Ocean basin requires modification of the geostrophic reference levels. The resulting meridional overturning circulation composed of northward flowing deep waters returning south at shallower levels becomes 11.9 plus or minus 2.7 x 10 super(9) kg s super(-1), roughly half the magnitude of a previous estimate using the same data. The bulk of the northward flowing bottom and lower deep water is converted to intermediate and upper deep water, which exits the basin as southward flow across 32 degree S. Less than one-third of the northward flowing deep waters upwells into the thermocline. Though the magnitude of the overturning circulation is reduced compared with previous estimates with this data set, the maximum basin-mean upwelling velocity required for mass continuity, 4.5 x 10 super(-5) cm s super(-1), is consistent with other estimates for the Indian Ocean basin and remains large compared with estimates for the deep Pacific basin. Since the meridional circulation is a major conveyor of heat and salinity in the Indian Ocean basin, a constraint on the magnitude of the meridional circulation provides bounds on the net heat and freshwater budgets of the region. The divergence of heat across the Indian Ocean basin north of 32 degree S is estimated to be 0.42 plus or minus 0.19 Petawatts and the convergence of freshwater to be 0.31 plus or minus 0.09 x 10 super(9) kg s super(-1). Both of these values are consistent with independent estimates, but reduced compared with calculations that do not consider the dissolved silica budget.
AN: 4228909
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TI: Phosphorus-limited bacterioplankton growth in the Sargasso Sea
AU: Cotner,-J.B.; Ammerman,-J.W.; Peele,-E.R.; Bentzen,-E.
AF: Dep. Wildl. and Fish. Sci., Texas A&M Univ., Coll. Stn., TX 77843-2258, USA
SO: AQUAT.-MICROB.-ECOL. 1997 vol. 13, no. 2, pp. 141-149
LA: English
ER: M (Marine)
AB: Oceanic central gyres cover large areas of the earth and contribute significantly to global productivity. Oceanic phytoplankton production is believed to be limited by nitrogen (N) in central gyres and iron (Fe) in high-nutrient low-chlorophyll regions. Bacterioplankton have been less studied but are believed to be limited by organic carbon. We report here that bacterioplankton in the Sargasso Sea were phosphorus (P) limited on cruises in 1992 and 1993. This assertion is supported by measurements of high dissolved and particulate N:P and C:P ratios, high alkaline phosphatase activity and phosphate uptake rates, and bacterioplankton growth rate responses in bioassays where inorganic P was added. Particulate C:P ratios were always higher than the Redfield ratio (106:1) and occasionally greater than 400:1. N:P ratios were 75:1 and 46:1 on 2 cruises and time-series data indicated that ratios were always greater than 24:1 over nearly a 2 yr span. Phosphate concentrations were extremely low in the euphotic zone (<10 nM) and biomass-normalized alkaline phosphatase activities indicated moderate to severe P limitation, with most severe limitation occurring in the spring. Bioassays indicated that heterotrophic bacteria may be P limited in the northwestern Sargasso Sea, especially in the spring. Limitation by P and not dissolved organic carbon may explain why dissolved organic carbon accumulates in the water column at that time.
AN: 4228310
118 of 313
TI: The seasonal cycle of nitrate in the Clyde Sea
AU: Rippeth,-T.P.; Jones,-K.J.
AF: Sch. Ocean Sci., Univ. Wales, Bangor, Menai Bridge, Gwynedd, UK
CO: 27. Int. Liege Colloquium on Ocean Hydrodynamics, Liege (Belgium), 8-12 May 1995
SO: Journal-of-Marine-Systems 1997 vol. 12, no. 1-4, pp. 299-310
NT: Special Volume: Processes in Regions of Freshwater Influence (PROFILE)
LA: English
ER: M (Marine); B (Brackish)
AB: The Clyde Sea is a deep, partially enclosed basin on the West Coast of Scotland which communicates with the adjacent North Channel of the Irish Sea via exchange flow over a relatively shallow entrance sill. The basin receives large inputs of nutrient rich freshwater which induces a reduction in surface salinities of up to 1.5 psu and maintains almost continuous stratification. Time series data collected in the area show a well defined seasonal cycle of stratification which has previously been explained with the aid of a one-dimensional filling box model. This model has been extended to examine the extent to which the observed seasonal cycles of nitrate and chlorophyll can be explained by the stepwise inclusion of additional non-conservative terms. The results show that, as a result of the interaction between the physical and biological seasonal cycles, nitrate accumulates in the Clyde Sea during the summer, which is then supplied to the North Channel of the Irish Sea during the winter and spring.
AN: 4227491
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TI: Influence of dissolved silicate on vertical flux of particulate biogenic matter
AU: Wassmann,-P.; Egge,-J.K.; Reigstad,-M.; Aksnes,-D.L.
AF: Norwegian Coll. Fish. Sci., Univ. Tromso, N-9037 Tromso, Norway
SO: MAR.-POLLUT.-BULL. 1997 vol. 33, no. 1-6, pp. 10-21
NT: Special issue: Programme on Marine Pollution (PMF). A Norwegian Research Programme (1992-1996).
LA: English
ER: M (Marine)
AB: The influence of dissolved silicate (DSi) addition on primary production, phytoplankton development and subsequent vertical export of particulate matter was studied in enclosures. Blooms of different phytoplankton communities were initiated in the upper part of 10 m deep enclosures supplied with nitrate and phosphate (NP) and nitrate, phosphate and silicate (NPS). Primary production was 31% higher in the NPS enclosure as compared to the NP enclosure over the experimental period of 27 days. Increased phytoplankton growth was mainly caused by mass development of diatoms in the NPS enclosure. Enhanced growth was accompanied by an increased vertical flux of organic matter (86, 15.9 and 16.9% in terms of chlorophyll, particulate nitrogen and particulate carbon, respectively) and was dominated by diatoms. The present study indicates that for each gram of DSi added, vertical flux was enhanced by 3.6 g C, implying that the ratio of DSi added/carbon exported was close to the Redfield ratio. Thus DSi presence appears to decrease the nutrient turn-over time in the euphotic zone by increasing vertical export. This may improve water quality of the surface layer of eutrophicated environments, but can lead to oxygen depletion of bottom waters.
AN: 4227046
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TI: Assessment of the role of copepods and ciliates in the release to solution of particulate DMSP
AU: Christaki,-U.; Belviso,-S.; Dolan,-J.R.; Corn,-M.
AF: Station Zoologique, URA 2077, BP 28, F-06230 Villefranche-sur-Mer, France
SO: Mar.-Ecol.-Prog.-Ser. 1996 vol. 141, no. 1-3, pp. 119-127
LA: English
ER: M (Marine)
AB: The exchanges between pools of particulate DMSP (pDMSP) and the total dissolved pool of DMSP and DMS [MS(P)], as well as dDMS(P) removal rates were investigated in 4 shipboard incubations of amended and size-fractionated natural planktonic assemblages of the Mediterranean Sea in spring 1995 and in a laboratory experiment with cultured populations. In the shipboard experiments, the effects of different concentrations of copepods and the presence /absence of micrograzers were assessed. Removal rates of dDMS(P), obtained from seawater samples spiked with dDMSP (dissolved DMSP), were linearly correlated with dDMS(P) levels in the range 10 to 50 nM and were unrelated to size-fractionation treatments. The biological turnover rate constant of dDMS(P) was 0.5/d. In most of the experiments, production of dDMS(P) was independent of copepod concentration and lowest in waters from which both copepods and micrograzers >10 mu m had been removed. Overall, the results of the shipboard experiments suggested that (1) dDMS(P) production occurred in the microplanktonic food web, probably because pDMSP occurred predominately in the size fraction <10 mu m and was unavailable for direct copepod consumption, and (2) dDMS(P) removal rates were likely due to organisms <10 mu m in size, probably bacteria. The laboratory experiment involved a common Mediterranean microplanktonic ciliate species (Strombidium sulcatum) grazing on a DMSP-containing Prymnesiophyceae (Isochrysis galbana). The rate of dDMS(P) release from algal DMSP was greatly increased when the phytoplankton was subjected to grazing by ciliates. The majority of prey pDMSP (>66%) was released to solution.
AN: 4213621
121 of 313
TI: Continental-scale biogeochemical cycles of the Amazon River system
AU: Richey,-J.E.; Victoria,-R.L.
AF: School of Oceanography, University of Washington, Seattle, WA, USA
CO: 26. Congress in Sao Paulo, Sao Paulo (Brazil), 23-29 Jul 1995
SO: heor.-Appl. Williams,-W.D.;Sladeckova,-A.-eds. Stuttgart-FRG Schweizerbart'-sche-Verlagsbuchhandlung 1996 vol. 26, no. 1 pp. 219-226
ST: Verh.-Int.-Ver.-Theor.-Angew.-Limnol.-Proc.-Int.-Assoc.-Theor.-Appl.-Limnol.-Trav.-Assoc.-Int.-Limnol.-Theor.-Appl. vol. 26, no. 1
LA: English
ER: F (Freshwater)
AN: 4212991
122 of 313
TI: Variability of nutrients and particulate matter in backbarrier tidal flats of the East Frisian Wadden Sea
AU: Liebezeit,-G.; Behrends,-B.; Kraul,-T.
AF: Forschungszentrum TERRAMARE, Schleusenstrasse 1, D-26382 Wilhelmshaven, FRG
SO: Senckenb.-Marit. 1996 vol. 26, no. 3-6, pp. 195-202
LA: English
ER: M (Marine)
AB: Dissolved inorganic nutrients and bulk particulate parameters (seston, organic carbon, total nitrogen, total phosphorus) were determined in May 1993, April 1994 and February 1995 in the backbarrier tidal systems of the East Frisian Islands, Norderney and Spiekeroog, using hourly sampling over 24 hours. Marked variability was encountered in all cases. This could not be related exclusively to tidal state alone. Possible causes including physical and biological mechanisms are discussed.
AN: 4212796
123 of 313
TI: Fluxes and masses of organic carbon in the ocean
AU: Romankevich,-E.A.; Vetrov,-A.A.
AF: Shirshov Inst. Oceanology, Russian Acad. Sci., ul. Krasikova 23, Moscow 117851, Russia
SO: GEOCHEM.-INT.;GEOKHIMIYA 1997 vol. 35, no. 9, pp. 829-836;no. 9, pp. 945-952
LA: English
ER: M (Marine); B (Brackish)
AB: The fluxes and masses of organic matter (OM) in the ocean were evaluated based on an analysis of data obtained by the Shirshov Institute of Oceanology, as well as on published data on the content of dissolved and particulate organic carbon in the surface layer of bottom sediments, in phytoplankton biomass, and in material introduced into the ocean from the land. The total influx of terrigenous OM from the land is estimated at 0.66 x 10 super(15) g C. The major contributors to the influx are river discharge of dissolved (210 x 10 super(12) g C sub(org)/yr) and particulate (250 x 10 super(12) g C sub(org)/yr) matter and eolian precipitation (174 x 10 super(12) g C sub(org)/yr). New data on primary productivity in the ocean (60 x 10 super(15) g C/yr) and the amount of C sub(org) buried in the marginal (150-240 x 10 super(12)) and deep-ocean (10 x 10 super(12) g C sub(org)/yr) sediments are discussed. The fossilization coefficients of OM in sediments at the ocean margin (0.8-1.3%), in the deep ocean (0.02%), and the world oceans as a whole (0.3-0.4%) are calculated.
AN: 4226670
124 of 313
TI: Geochemical consequences of microbiological processes on the northwestern Black Sea shelf
AU: Lein,-A.Yu.; Pimenov,-N.V.; Rusanov,-I.I.; Miller,-Yu.M.; Ivanov,-M.V.
AF: Vernadsky Inst. Geochemistry and Analytical Chem., Russian Acad. Sci., ul. Kosygina 19, Moscow 117975, Russia
SO: GEOCHEM.-INT.;GEOKHIMIYA 1997 vol. 35, no. 10, pp. 865-883;no. 10, pp. 985-1004
LA: English
ER: M (Marine); B (Brackish)
AB: The rates of H sub(2)S and CH sub(4) production and microbial CH sub(4) oxidation on the surface (0-30 cm) of the bottom sediments on the low-depth northwestern Black Sea shelf, which suffers the highest industrial impact, were estimated from super(35)S and super(14)C radioisotope measurements. It was shown that microbial processes of sulfate reduction and methane production are accompanied with changes in O sub(2) concentration in the near-bottom waters, salt composition of mud waters, and isotopic composition of sulfate sulfur and bicarbonate carbon. Solid phases of mud feature the formation of hydrogen sulfide derivatives and carbonate minerals. An expressed exponential dependence of the isotopic composition of reduced sulfur compounds on sulfate reduction rate was observed. In sediments that exhibit high rates of sulfate reduction, the super(13)C concentration of autogenic carbonates and C sub(org) decline. Values of delta super(13)C (from -68 to -72ppt) prove its autochtonous microbial origin. Comparing these values of hydrogen sulfide flow with those of the past reveals a trend towards decline of hydrogen sulfide formation rate. In August 1995, no oxygen deficiency was observed in the surveyed area. The main peak of methane production was observed below the 0- to 30-cm layer. The methane concentrations in sediments in the Danube estuary and on the northern Bulgarian shelf reached 4-5 l/m super(2). A substantial amount of methane can transfer from sediments into water and air. The CH sub(4) flow from 0- to 30-cm layer, allowing for microbial CH sub(4) oxidation, proceeds at a rate of at least 1000 m super(3)/year.
AN: 4226669
125 of 313
TI: A timescale for dissolved organic carbon production in Equatorial Pacific surface waters
AU: Archer,-D.; Peltzer,-E.T.; Kirchman,-D.L.
AF: Dep. Geophysical Sci., Univ. Chicago, Chicago, IL, USA
SO: GLOBAL-BIOGEOCHEM.-CYCLES 1997 vol. 11, no. 3, pp. 435-452
LA: English
ER: M (Marine)
AN: 4223038
126 of 313
TI: One-dimensional modeling of nitrogen and sulfur cycles in the aphotic zones of the Black and Arabian Seas
AU: Yakushev,-E.V.; Neretin,-L.N.
AF: P.P. Shirshov Inst. Oceanology, Russian Acad. Sci., Anokhin St. 6-486, Moscow 117602, Russia
SO: GLOBAL-BIOGEOCHEM.-CYCLES 1997 vol. 11, no. 3, pp. 401-414
LA: English
ER: M (Marine)
AN: 4223037
127 of 313
TI: Active uptake of bicarbonate by diatoms
AU: Tortell,-P.D.; Reinfelder,-J.R.; Morel,-F.M.M.
AF: Dep. Ecol. and Evol. Biol., Princeton Univ., Princeton, NJ 08544, USA
SO: NATURE 1997 vol. 390, no. 6657, pp. 243-244
LA: English
ER: M (Marine)
AB: Marine diatoms play a predominant role in the biological carbon pump transferring carbon dioxide from surface to deep waters. Laboratory studies show that a number of species take up HCO sub(3) super(-) and concentrate inorganic carbon intracellularly allowing rapid growth despite low CO sub(2) availability. In contrast, many oceanographers, particularly when interpreting carbon isotope data, have made the assumption that diatoms do not utilize the abundant HCO sub(3) super(-) in seawater but rather take up CO sub(2) by diffusion. This has led to the hypothesis that large diatoms may be CO sub(2)-limited in the oceans. We now demonstrate active uptake of HCO sub(3) super(-) in the field and a carbon-concentrating mechanism in coastal Atlantic diatoms. By manipulating p sub(CO2) we show that growth of large diatoms in the California upwelling is not limited by CO sub(2) availability. We ran short-term H super(14)CO sub(3) super(-)-uptake experiments using samples dominated by large (> 30 mu m) diatoms (Asterionella, Nitzchia and Rhizosolenia) collected from Delaware Bay in 1997 during a spring phytoplankton bloom.
AN: 4222179
128 of 313
TI: Evolution of cadmium and lead contents in Antarctic coastal seawater during the austral summer
AU: Scarponi,-G.; Capodaglio,-G.; Turetta,-C.; Barbante,-C.; Cecchini,-M.; Toscano,-G.; Cescon,-P.
AF: Dep. Environ. Sci., Univ. Venice Ca' Foscari, I-30123 Venice, Italy
SO: INT.-J.-ENVIRON.-ANAL.-CHEM. 1997 vol. 66, no. 1, pp. 23-49
LA: English
ER: M (Marine)
AB: The seasonal evolution of the cadmium and lead distribution in the water column of the Gerlache Inlet (Ross Sea) was studied during the 1990-91 austral summer. Measurements were carried out by Anodic Stripping Voltammetry in Antarctica immediately after the collection and filtration of samples. The concentrations of both metals were homogeneous before the phytoplankton bloom with mean values of 0.71 (SD 0.10) and 0.116 (SD 0.014) nmol/l for cadmium and lead respectively. A subsequent depletion in metal concentration was observed in the shallow waters. The surface concentration of cadmium decreased to about 0.1 nmol/l at the end of the season. The vertical distribution of lead was less affected by the seasonal evolution and the mean surface concentration decreased to 0.044 nmol/l in the same period. The results are evaluated with respect to physical and biological processes in the area examined and compared with those obtained on previous expeditions in the same area.
AN: 4221707
129 of 313
TI: Riverine contribution of biogenic silica to the oceanic silica budget
AU: Conley,-D.J.
AF: Natl. Environ. Res. Inst., Dep. Mar. Ecol. and Microbiol., P.O. Box 358, DK-4000 Roskilde, Denmark
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 4, pp. 774-777
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Biological uptake of dissolved silicate (DSi) and formation of biogenic silica (BSi) during diatom growth modifies the form of Si carried from the continents to the world ocean. Significant concentrations of BSi, averaging 28.0 mu mol L super(-1), are found in all sizes of rivers. The global contribution of BSi carried by rivers was estimated as 1.05 plus or minus 0.20 Tmol Si year super(-1). Combined with the global mean riverine DSi concentration of 150 mu mol liter super(-1), 16% of the gross riverine Si load is delivered to the world ocean as BSi. Most of this BSi would be remobilized by dissolution in marine environments. These results demonstrate that the contribution of biogenic silica carried in suspension by rivers is an important component in the world ocean Si budget that has not been recognized previously.
AN: 4221072
130 of 313
TI: Biogeochemistry of trace metals (Mn, Sr, Rb, Ba, Cu, Zn, Pb and Cd) in a river-wetland-lake system (Balaton Region, Hungary)
AU: Elbaz-Poulichet,-F.; Nagy,-A.; Cserny,-T.; Pomogyi,-P.
AF: ISTEEM-UMR CNRS Geofluides-Bassins-Eau, Univ. Montpellier II, CC057.34095 Montpellier Cedex 5, France
SO: AQUAT.-GEOCHEM. 1997 vol. 2, no. 4, pp. 379-402
LA: English
ER: F (Freshwater)
AB: Mn, Sr, Ba, Rb, Cu, Zn, Pb and Cd concentrations have been measured seasonally in the water and deposited sediments of the system comprising: Zala river (main input) - Lakes Kis-Balaton 1 and 2 (small artificial lakes created in a former bay of Lake Balaton) - Keszthely bay (hypertrophic part of Lake Balaton). The concentrations of the trace elements together with pH, alkalinity, dissolved cations (Ca super(2+), Mg super(2+), Na super(+), and K super(+)), dissolved inorganic ligands (Cl super(-), SO sub(4) super(2-)), particulate Al, Ca, inorganic and organic carbon are used to assess the contamination of the study area and biogeochemical processes controlling trace element concentrations. Thermodynamic speciation calculations have also been utilized to enhance our understanding of the system. In the sediments Rb, Ba, Cu and Zn concentrations were mainly controlled by the abundance of the aluminosilicate fraction. Strontium was mainly associated with the calcium carbonate fraction. The aluminosilicate fraction constitutes a major sink for Mn and Cd but the concentration of these elements are also strongly related to calcite precipitation. The main processes that control the dissolved distribution of trace elements in the Balaton system were: solid phase formation (carbonate) for Mn; coprecipitation with calcite for Sr, Ba, Rb and possibly Mn and Cd; adsorption /desorption processes (pH dependent) for Zn and Pb; solubilization of Mn and precipitation of Cd and Cu in reed covered wetland areas where anoxic conditions were probably existing during the warm season. A preliminary budget of atmospheric and river input to Lake Balaton has also been outlined. Although Lake Balaton, is subjected to anthropogenic inputs mainly from agricultural and domestic activities, their impact on trace element concentrations in the Balaton system is very limited due to the efficiency of removal processes (i.e. adsorption and co-precipitation) and to high sedimentation rates and strong sediment re-suspension. Anthropogenic inputs are only detected for Pb.
AN: 4220912
131 of 313
TI: Aerobic conversion of dimethyl sulfide and hydrogen sulfide by Methylophaga sulfidovorans: Implications for modeling DMS conversion in a microbial mat
AU: De-Zwart,-J.M.M.; Kuenen,-J.G.
AF: Dep. Microbiol. and Enzymology, Delft Univ. Technol., Julianalaan 67, 2628 BC Delft, The Netherlands
SO: FEMS-MICROBIOL.-ECOL. 1997 vol. 22, no. 2, pp. 155-165
LA: English
ER: M (Marine)
AB: Methylophaga sulfidovorans is an obligately methylotrophic, DMS-oxidizing organism, isolated from microbial mat sediment. DMS and H sub(2)S, both present in marine microbial mats, can be used as energy sources by this organism. In batch cultures of M. sulfidovorans, sequential H sub(2)S and DMS utilization occurred. In energy-limited continuous cultures, with DMS, methanol and H sub(2)S as substrates, mixotrophic growth of M. sulfidovorans was observed, showing that at low concentrations these substrates can be used simultaneously. Oxygen and H sub(2)S uptake experiments showed that the critical concentration at which sulfide inhibition of DMS oxidation occurred was between 15 and 40 mu mol l super(-1). Also in crude enrichments of DMS oxidizers a decrease of 50% in DMS-oxidizing capacity for about 200 mu mol l super(-1) H sub(2)S was observed. The new physiological data obtained with the pure cultures of M. sulfidovorans were incorporated in a compartment model of a microbial mat and gave improved predictions of DMS profiles and DMS emissions from the mat, both when phototrophic activity is present (day) and when it is absent (night).
AN: 4220666
132 of 313
TI: The population structure and ecology of the Antarctic scallop Adamussium colbecki (Smith, 1902) at Terra Nova Bay (Ross Sea, Antarctica)
AU: Cattaneo-Vietti,-R.; Chiantore,-M.; Albertelli,-G.
AF: Istituto di Scienze Ambientali Mar., Univ. di Genova., C.P. 79, 16038 S. Margherita Ligure, Genova, Italy
CO: 12. Int. Malacological Congress: Symp. on Ecology of Molluscs, Vigo (Spain), 3-8 Sep 1995
SO: ECOLOGY-OF-MARINE-MOLLUSCS. Ros,-J.;Guerra,-A.-eds. 1997 vol. 61, no. suppl. 2 pp. 15-24
ST: Scientia-Marina-Barcelona vol. 61, no. suppl. 2
RN: NIPO 179-97-037-5 (179970375)
LA: English
ER: M (Marine)
AB: One of the main purposes of the core project "Ecology and Biogeochemistry of the Southern Ocean" (Italian Antarctic Programme-PNRA) is to understand the utilization and ultimate fate of the organic matter sedimenting through the water column and its influence in the structure of the macrobenthic assemblages. At Terra Nova Bay (Ross Sea), the scallop Adamussium colbecki (Smith, 1902) constitutes large beds up to 70-80 m depth. The importance of this population in the local community structure requires a closer examination of its structure and dynamics, in order to assess its role in the coastal organic matter flux, and for this reason it has been studied during several years (1987-92) in areas close to the Italian Station and particularly in the Summer 1993/94. Its high density (up to 60 ind m super(-2)) and biomass (up to 120 g m super(-2) dry weight of soft tissues) values are probably linked to slow growth rate and reduced reproductive capacities. X-ray studies on the shell confirmed the slow growth rate of this species, which averages about 0.8 cm yr super(-1). The analysis of the ratio between length and height of the shell (generally similar to 1) shows a significative inversion at the age of maturity, when the byssally attached juveniles become free from the adult valves. A comparison of the gonadosomatic index in the population between December and January suggests that sexual maturity is reached late in this season and is strongly related to the water column food supply consequent to the phytoplankton bloom. Comparing the size-frequency distribution of this population in different years, it is possible to observe a cohort gap, shifting through the study period, and probably caused by unsuccessful recruitments from 6 to 9 years before 1994. Slow growth rate and intermittent recruitment suggest that an eventual commercial exploitation of this species, abundant but patchly distributed in a narrow bathymetric range, would quickly result in overfishing and commercial failure.
AN: 4220662
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TI: Cycling of iron, manganese, and phosphate in a meromictic lake
AU: Hongve,-D.
AF: Natl. Inst. Public Health, P.O. Box 4404 Torshor, N-0403 Oslo, Norway
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 4, pp. 635-647
LA: English
ER: F (Freshwater)
AB: Lake Nordbytjernet (Southeast Norway) had up to 40 mg liter super(-1) dissolved iron and 67 mg liter super(-1) dissolved manganese in a stagnant layer. The ratio between iron and manganese loading was around 3:1, while the inventory of manganese was six times higher than for iron. High concentrations of dissolved iron occurred solely under strictly anoxic conditions, while dissolved manganese was unaffected by intrusion of oxygen during the autumnal partial circulation. Mixed potentials caused by oxidation of ferrous iron and reduction of manganic oxide or O sub(2) controlled the redox potential values, while dissolved manganese appeared to have no influence. The following main processes controlled the sedimentation rates: fluvial supply of suspended material, precipitation of ferric hydroxide and manganese oxide from the water column, and plankton production. Sorption to ferric hydroxide in the oxic zone and reductive desorption in the anoxic zone controlled the deep water stratification of phosphorus, dissolved organic carbon, and some major cations. No similar effects were seen for manganese sedimentation. The iron sedimentation rate was enhanced in the anoxic zone due to redox coupling of iron oxidation and manganese reduction. Phosphorus was depleted in the anoxic zone during periods of substantial ferric hydroxide sedimentation. Sedimentation of manganese under anoxic conditions seemed to be governed by precipitation of carbonate and phosphate. Residence times in the lake were 0.2 yr for iron and phosphorous vs. 3.3 yr for manganese and 1.4 yr for water.
AN: 4219577
134 of 313
TI: Short-term sediment trap fluxes from Chatham Rise, southwest Pacific Ocean
AU: Nodder,-S.D.
AF: New Zealand Oceanographic Institute, National Institute of Water & Atmospheric Research Ltd, P.O. Box 14-901, Wellington, New Zealand
SO: LIMNOL.-OCEANOGR. 1997 vol. 42, no. 4, pp. 777-783
LA: English
ER: M (Marine)
AB: Sediment trap, nephelometer, and particulate matter (PM) data were collected in the vicinity of the Subtropical Convergence, north of Chatham Rise (42-43 degree S), southwest Pacific Ocean, in austral autumn 1992. Free-floating cylindrical sediment traps were deployed below the euphotic zone at 200-, 300-, and 500-m water depths. Increases in total mass flux and concomitant proportional decreases in other particulate fluxes (total carbon, nitrogen, and phosphorus) with depth reflected the collection of relatively refractory material, enriched in particulate carbon, as evinced by increases in C:N and C:P ratios below 300 m. Nephelometer and PM concentration profiles indicate that resuspension of sea-floor sediments from the nearby submarine high (Chatham Rise) probably contributed to the observed increase in total mass flux with depth. Published pCO sub(2) estimates, biological productivity data, and moderate particulate fluxes, as indicated by the present study suggest that oceanic water types east of New Zealand may be a biologically mediated regional sink for atmospheric CO sub(2).
AN: 4218502
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TI: Experimental determination of the organic carbon flux from open-ocean surface waters
AU: Emerson,-S.; Quay,-P.; Karl,-D.; Winn,-C.; Tupas,-L.; Landry,-M.
AF: Sch. Oceanogr., Univ. Washington, Seattle, WA 98195, USA
SO: NATURE 1997 vol. 389, no. 6654, pp. 951-954
LA: English
ER: M (Marine)
AB: The flux of biologically produced organic carbon from the euphotic zone of the ocean to the deep waters below--the "biological organic carbon pump"--is one of the main controls on the carbon dioxide partial pressure in the atmosphere. Accurate determination of this flux is therefore critically important for understanding the global carbon cycle and its response to climate change. Our goal is to assess how accurately the biological organic carbon pump can be determined at a single location and to constrain estimates of the global value. As there are no standards against which such environmental fluxes can be measured, we assess accuracy by comparing results from three independent experimental approaches for measuring the net annual export of organic carbon from the euphotic zone in the subtropical North Pacific Ocean near Hawaii. Mass balances of dissolved oxygen, inorganic carbon and organic carbon yield estimates of the organic carbon export flux of 2.7 plus or minus 1.7, 1.6 plus or minus 0.9 and 2.0 plus or minus 0.9 mol C/m super(2)/yr, respectively. These three estimates are not significantly different, and establish the present analytically attainable accuracy at this location to be about plus or minus 50%. If 2.0 mol C/m super(2)/yr is typically of the organic carbon export flux in the subtropical ocean, then this vast region, often considered to be a biological desert, may be responsible for up to half of the global-ocean biological organic carbon pump.
AN: 4115446
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TI: Selenate-regulation of sulfur metabolism in a cyanobacterium, Phormidium uncinatum
AU: Bagchi,-D.; Verma,-D.
AF: Dep. Biol. Sci., R.D. Univ., Jabalpur 482 001 M.P., India
SO: J.-PLANT-PHYSIOL. 1997 vol. 150, no. 6, pp. 762-764
LA: English
ER: F (Freshwater)
AB: Selenate-mediated regulation of sulfate assimilation was studied in Phormidium uncinatum and its selenate resistant mutant. Selenate-caused suppression of sulfate-supported wild type growth was due to inactivation of ATP-sulfurylase activity. Mutation led to loss of this enzyme and growth with sulfate; therefore, thiosulfate served as sulfur source. Both strains grew with several alternate sulfur sources, cysteine and methionine included. L-cysteine repressed sulfurylase and cysteine synthase but activated its desulfhydrase and thiosulfate reductase activities. Mutant enzymes were deregulated for activation.
AN: 4215866
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TI: Mineralization and burial of organic carbon in sediments of the southern Weddell Sea (Antarctica)
AU: Hulth,-S.; Tengberg,-A.; Landen,-A.; Hall,-P.O.J.
AF: Dep. Analytical and Mar. Chem., Univ. Goeteborg, S-412 96 Goeteborg, Sweden
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 6, pp. 955-981
LA: English
ER: M (Marine)
AB: Benthic fluxes of oxygen, alkalinity (A sub(T)), total carbonate (C sub(T) or capital sigma CO sub(2)) and dissolved organic carbon (DOC) were measured during sediment-water incubations at 16 stations in the southern Weddell Sea (Antarctica) with water depths between 280 and 2514 m. The total sediment oxygen consumption rates (TSOC) were in general low (1.74-3.61 mmol m super(-2) day super(-1)) and more comparable to measurements in slope and deep-sea sediments at a few thousand meters water depth. The decrease of TSOC with water depth was lower than that observed in many other seas. The mean carbon to nitrogen ratio (C/N) in the solid phase of surficial sediment was 8.3. Measured benthic fluxes of alkalinity, corrected for contributions from nitrification and denitrification, were quantitatively used to correct the fluxes of total carbonate for dissolution of solid phase carbonates. The capital sigma CO sub(2) fluxes, originating from carbonate dissolution (0.166-1.77 mmol m super(-2) day super(-1)), were 2.6-71% of the capital sigma CO sub(2) fluxes (0.984-3.73 mmol m super(-2) day super(-1)) resulting from organic carbon oxidation. Measured benthic fluxes of oxygen, capital sigma CO sub(2) and nitrate were, together with estimated denitrification rates and sediment C/N ratios, used to model respiration quotients (RQ) for organic carbon oxidation and estimate composition of the organic matter undergoing degradation. Modelled RQ varied roughly between 2/3 and 1 (mean 0.87). Measured fluxes of capital sigma CO sub(2) were 1.6-3.2 times higher than integrated organic C mineralization rates (measured during closed incubations of sieved, homogenized sediment), indicating macrofaunal (plus possibly meiofaunal) respiration to be important. However, low abundances of bioirrigating benthic macrofauna and small differences in benthic fluxes of oxygen, capital sigma CO sub(2) and alkalinity found between replicate sediment cores, suggested that macrofaunal respiration was quantitatively unimportant in these sediments. The higher measured fluxes of capital sigma CO sub(2), compared to the integrated mineralization rates, were therefore most likely caused by a large fraction of the respiration occurring directly on the sediment surface. This degradation of newly deposited organic matter was not reflected in the integrated organic C mineralization rates. Also, there was no obvious effect of this surficial degradation process on the pore water distributions of capital sigma CO sub(2). Benthic mass balances of carbon revealed that benthic fluxes of DOC were 3-147% of the corrected fluxes of capital sigma CO sub(2), and the recycling efficiencies (E) were up to 35% higher if the DOC fluxes were included in the calculations of E, rather than the inorganic capital sigma CO sub(2) flux alone. The recycling efficiencies, including the benthic flux of DOC, ranged between 57 and 88% (mean 78%). Measured rates of inorganic C accumulation (for most stations <0.3 mmol C m super(-2) day super(-1)) were a factor of 6-7 lower than organic C accumulation rates (0.457-1.94 mmol C m super(-2) day super(-1)).
AN: 4215863
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TI: Controls on the distributions of organic carbon and nitrogen in the eastern Pacific Ocean
AU: Hansell,-D.A.; Waterhouse,-T.Y.
AF: Bermuda Biol. Stn. for Res. Inc., 17 Biological Lane, St Georges, GE-01, Bermuda
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 5, pp. 843-857
LA: English
ER: M (Marine)
AB: Measurements of total organic carbon (TOC) and nitrogen (TON) were made on the WOCE P18 line (from 67 degree S to 23 degree N along 103/110 degree W). There was an accumulation of TOC on the equator and in the oligotrophic waters north and south of the equator. The concentrations of TOC were well correlated with temperature, indicating an important physical control on its distribution. The boundary separating shallow, TOC-rich water from deep, TOC-poor water overlaid the main thermocline. This observation suggests that water column stability or residence time imparted by the main thermocline is a primary determinant of TOC accumulation. Elevated TON concentrations were found in all surface waters, with the lowest values found in the region of 20-35 degree S. Net TON drawdown in the South Pacific subtropical gyre, likely due to biological utilization and vertical export of the nitrogen, was initiated with depletion of equatorially upwelled nitrate. The degree to which inorganic nitrogen was limiting in the surface layer south of the equator served to control the concentrations of TON. Such controls were not exerted on organic carbon, as reflected by increasing C:N ratios of organic matter as TON was removed. Unlike the findings in the South Pacific, TON concentrations in oligotrophic waters north of the equator were frequently higher than on the equator. Such accumulations are hypothesized to be maintained from nitrogen fixation, nitrogen input due to vertical migration of autotrophs or diffusive flux of inorganic nitrogen into the euphotic zone across the relatively shallow nitracline.
AN: 4215862
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TI: The effect of resuspension on chemical exchanges at the sediment-water interface in the deep sea - A modelling and natural radiotracer approach
AU: Rutgers-van-der-Loeff,-M.M.; Boudreau,-B.P.
AF: Alfred-Wegener Inst. for Polar and Mar. Res., P.O. Box 120161, D-27515 Bremerhaven, Germany
SO: J.-MAR.-SYST. 1997 vol. 11, no. 3-4, pp. 305-342
NT: Includes special section: SCOR Working Group 95: Sediment Suspension and Sea Bed Properties.
LA: English
ER: M (Marine)
AB: We review the processes responsible for the formation of vertical gradients in the chemical composition of suspended particles across the benthic nepheloid layer. Such gradients have usually been explained by resuspension of surface sediments, but it is shown here that these gradients can only be understood as part of a dynamic exchange between the water column and the sediments. A coupled model, developed in a companion paper, is expanded to include chemical reactions above and below the sediment-water interface. Three cases are discussed: A tracer with first-order decay (Model 1), the dissolution of a major constituent (Model 2), and a particle-reactive tracer with first-order decay and production in the water column (Model 3). Using typical parameter values for a well-developed benthic nepheloid layer, the three models reproduce typical distributions of C sub(org) (organic carbon), opal, and super(234)Th, respectively, on particles above and below the sediment-water interface. Sensitivity analyses illustrate how bioturbation can cause the large discrepancy observed between suspended and surface sediment C sub(org) values (Model 1). The model also reconciles this observed discrepancy with observations that the major part of the decomposition takes place within the sediment. For opal (Model 2), the influence of resuspension on the burial rate of opal is shown to be negligible, as long as dissolution follows first-order kinetics and is not enhanced by turbulence in the suspended phase. The modelling of super(234)Th (Model 3) successfully links the depletion of super(234)Th in bottom waters with the distribution of excess super(234)Th in surface sediments and on resuspended particles. super(234)Th is a powerful example of the tools supplied by the radioactive daughters of the natural U and Th decay series in studying fluxes and exchange rates of solutes and particles across the sediment-water interface. A short review is given of these tools, and it is shown how they can be used to obtain rate information required to apply and calibrate specific resuspension models.
AN: 4215227
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TI: Biomass and litter dynamics in a Melaleuca forest on a seasonally inundated floodplain in tropical, northern Australia
AU: Finlayson,-C.M.; Cowie,-I.D.; Bailey,-B.J.
AF: Alligator Rivers Region Res. Inst., Office Supervising Scientist, Post Office, Jabiru, NT 0886, Australia
SO: WETLANDS-ECOL.-MANAGE. 1993 vol. 2, no. 4, pp. 177-188
LA: English
ER: F (Freshwater)
AB: Litterfall from a Melaleuca forest was investigated as part of chemical cycling studies on the Magela Creek floodplain in tropical, northern Australia. The forest contained two species of tree, Melaleuca cajaputi and Melaleuca viridiflora, with a combined average density of 294 trees ha super(-1). The M. viridiflora trees had diameter breast height measurements ranging from 11.8 to 62.0 cm, median class 25.1-30.0 cm and a mean value of 29.2 plus or minus 1.0 cm, compared to 13.0 to 66.3 cm, 30.1-35.0 cm and 33.5 plus or minus 1.0 cm for M. cajaputi trees. A regression model between tree height, diameter breast height and fresh weight was determined and used to calculate average tree weights of 775 plus or minus 1.6 kg for M. viridiflora and 1009 plus or minus 1.6 kg for M. cajaputi, and a total above-ground fresh weight of 263 plus or minus 0.3 t ha super(-1). The weight of litter recorded each month on the ground beneath the tree canopy ranged from 582 plus or minus 103 to 2176 plus or minus 376 g m super(-2) with a monthly mean value of 1105 plus or minus 51 g m super(-2). The coefficient of variation of 52% on this mean indicates the large spatial and temporal variability in litter distribution over the study site. This variability was greatly affected by the pattern of water flow and litter transport during the Wet season. Litterfall from the trees was evaluated using two techniques - nets and trays. The results from these techniques were not significantly different with annual litterfall collected in the nets being 705 plus or minus 25 g m super(-2) and in the trays 716 plus or minus 49 g m super(-2). The maximum monthly amount of litterfall, 108 plus or minus 55 g m super(-2), occurred during the Dry season months of June-July. Leaf material comprised 70% of the total annual weight of litter, 480 plus or minus 29 g m super(-2) in the nets and 495 plus or minus 21 g m super(-2) in the trays. The tree density and weight of litter suggest that the Melaleuca forests are highly productive and contribute a large amount of material to the detrital/debris turnover cycle on the floodplain. (DBO)
AN: 4214329
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TI: Oxygen pore water profiles in continental shelf sediments of the North Sea: Turbulent versus molecular diffusion
AU: Lohse,-L.; Epping,-E.H.G.; Helder,-W.; Raaphorst,-W.-van
AF: Netherlands Institute for Sea Research (NIOZ), PO Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: Mar.-Ecol.-Prog.-Ser. 1996 vol. 145, no. 1-3, pp. 63-75
NT: Incl. bibliogr.: 52 refs.
LA: English
ER: M (Marine)
AB: Oxygen pore water profiles in North Sea sediments were measured with microelectrodes during 2 contrasting seasons. The measurements were conducted in a wide variety of sediments, including non-depositional areas on the southern shelf as well as depositional areas in the Skagerrak. All measurements were performed within minutes on board at in situ emperature. The curvature of oxygen profiles in sandy sediments on the southern shelf indicated the presence of a surface layer characterised by enhanced diffusion. The occurrence of enhanced diffusion was related to sedimentological and seasonal differences. Quantitative evaluation of the pore water profiles by a diffusion-reaction model indicated that the effective diffusion coefficients in a 0.2 to 16 mm subsurface layer were 1.5 to >100 times higher than the molecular diffusion coefficient. Highest effective diffusion coefficients were reported for non-depositional sediments characterised by low diffusive oxygen fluxes. Oxygen profiles in sediments of the depositional area of the Skagerrak indicated constant diffusivity throughout the sediment column. Diffusive fluxes calculated from profiles ranged from 5.2 to 8.9 mmol/m2/ in August 1991, and were between 0.8 and 6.2 mmol/m2/ in February 1992. Seasonal differences in sediments located in the Skagerrak area were minor. It is proposed that near-bottom tidal currents induce enhanced diffusion transport processes in the upper millimetres of the sandy sediments of the southern North Sea, while less energetic hydrodynamical conditions in the depositional area of the Skagerrak favour sediment-water exchange based on molecular diffusion only. Biogeochemical implications of the enhanced diffusivity close to the sediment-water interface are discussed.
AN: 4213835
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TI: Rapid subduction of organic matter by maldanid polychaetes on the North Carolina slope
AU: Levin,-L.; Blair,-N.; DeMaster,-D.; Plaia,-G.; Fornes,-W.; Martin,-C.; Thomas,-C.
AF: Mar. Life Res. Group, Scripps Inst. Oceanogr., La Jolla, CA 92093-0218, USA
SO: J.-MAR.-RES. 1997 vol. 55, no. 3, pp. 595-611
LA: English
ER: M (Marine)
AB: In situ tracer experiments conducted on the North Carolina continental slope reveal that tube-building worms (Polychaeta: Maldanidae) can, without ingestion, rapidly subduct freshly deposited, algal carbon ( super(13)C-labeled diatoms) and inorganic materials (slope sediment and glass beads) to depths of 10 cm or more in the sediment column. Transport over 1.5 days appears to be nonselective but spatially patchy, creating localized, deep hotspots. As a result of this transport, relatively fresh organic matter becomes available soon after deposition to deep-dwelling microbes and other infauna, and both aerobic and anaerobic processes may be enhanced. Comparison of tracer subduction with estimates from a diffusive mixing model using super(234)Th-based coefficients, suggests that maldanid subduction activities, within 1.5 d of particle deposition, could account for 25-100% of the mixing below 5 cm that occurs on 100-day time scales. Comparisons of community data from the North Carolina slope for different places and times indicate a correlation between the abundance of deep-dwelling maldanids and the abundance and the dwelling depth in the sediment column of other infauna. Pulsed inputs of organic matter occur frequently in margin environments and maldanid polychaetes are a common component of continental slope macrobenthos. Thus, the activities we observe are likely to be widespread and significant for chemical cycling (natural and anthropogenic materials) on the slope. We propose that species like maldanids, that rapidly redistribute labile organic matter within the seabed, probably function as keystone resource modifiers. They may exert a disproportionately strong influence (relative to their abundance) on the structure of infaunal communities and on the timing, location and nature of organic matter diagenesis and burial in continental margin sediments.
AN: 4209889
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TI: Adsorption and pollutant transport by marine aerosol
AU: Cini,-R.; Loglio,-G.
AF: Dep. Organic Chem., Univ. Florence, Via G. Capponi 9, 50121 Florence, Italy
SO: MAR.-POLLUT.-BULL. 1997 vol. 34, no. 7, pp. 501-504
LA: English
ER: M (Marine)
AB: Many natural and man-made surfactants do not have a homogeneous distribution in the water column but spontaneously segregate (adsorb) at the marine water-air interface. The importance of this well-known process is often underestimated in marine aerosol studies. The humic substances represent one of the most important fractions of water soluble natural surfactants. The ability of these products to interact with inorganic ions and organic substances, many of which are objectionable, explains the pollutant presence and enrichment not only at the marine surface but also in marine aerosols. Analysis of the role played by the adsorption process in marine aerosol formation may give a new basis for a more complete explanation of the composition of the fine aerosol fraction and of long-range pollutant transport to remote areas. Additionally, a fuller interpretation of vegetation damage occurring in coastal areas may be achieved. We argue that the role of the biogenic surfactant matter, which is present in traces in marine surface water, is currently underestimated in transport processes.
AN: 4208223
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TI: Leaf litter in a Sonoran Desert stream ecosystem
AU: Schade,-J.D.; Fisher,-S.G.
AF: Zool. Dep., Arizona State Univ., Tempe, AZ 85287-1501, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 3, pp. 612-626
LA: English
ER: F (Freshwater)
AB: Leaf litter is an important functional component of mesic stream ecosystems; however, the importance of leaf litter has not been established for streams of the southwestern North American deserts. These streams exhibit many functional and structural characteristics that are the result of the pattern and amount of precipitation and which differ from their mesic counterparts. Our objective was to determine the influence of leaf litter on ecosystem processes of Sycamore Creek, Arizona, a typical Sonoran Desert stream, and to compare these results with knowledge gained from other regions. Patterns of nitrogen dynamics and respiration during leaf decomposition were similar for leaf packs in Sycamore Creek and previous studies of mesic streams. Macroinvertebrates in Sycamore Creek colonized natural and artificial leaf packs equally, and taxonomic composition did not differ significantly between leaf types, or between leaf pack communities and benthic communities. Shredder macroinvertebrates feeding on leaf material were absent. Leaf litter input to Sycamore Creek was low and litter residence time was reduced by flash floods. As a result, leaves played an insignificant role in terms of nutrient dynamics, energy flow, and macroinvertebrate assemblages in this ecosystem. Differences in the role of leaf litter between regions are attributed to channel and riparian form and to the frequency of severe disturbance, which are functions of meteorologic, hydrologic, and geomorphic features of the landscape.
AN: 4208020
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TI: Belgian scientific research programme on the Antarctic
SO: 1997 30 pp
RN: ANTAR/97/1 (ANTAR971)
LA: English
AB: This volume presents an overview of the results of the research projects funded under the Third Phase of the Belgian Scientific Research Programme on the Antarctic (1992-1996). Such research effort aimed at contributing to the development of the knowledge required for a science-based conservation and management of the Antarctic environment and to the assessment of the mechanisms through which the Antarctic and the global climate interact. Emphasis was given on a multi-disciplinary approach of the dynamics of the global functioning of Antarctic main natural systems and of their evolution and interactions. The programme comprises seven research lines under three priority areas. They are: ECODYNAMICS OF THE SOUTHERN OCEAN AND INTERACTIONS WITH THE CLIMATE: Biogeochemical fluxes and cycles in the main trophic compartments; Modelling the global dynamics of ecosystems; Assessment of the role of "new production" in the burial of atmospheric CO sub(2) by the Southern Ocean. EVOLUTION AND PROTECTION OF MARINE ECOSYSTEMS: Application of predictive ecological models to simulate ecosystem responses to man-made climatic disturbances; Study of hydrocarbons spills dispersion. ROLE OF THE ANTARCTIC IN GLOBAL CHANGES: Ocean-Cryosphere-Atmosphere interactions. Sedimentary palaeoenvironment.
AN: 4206769
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TI: Benthic-pelagic links: Responses of benthos to water-column nutrient enrichment
AU: Blumenshine,-S.C.; Vadeboncoeur,-Y.; Lodge,-D.M.; Cottingham,-K.L.; Knight,-S.E.
AF: Dep. Biol. Sci., Univ. Notre Dame, Notre Dame, IN 46556, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 3, pp. 466-479
LA: English
ER: F (Freshwater)
AB: Although the responses of pelagic algae and invertebrates to gradients of nutrient enrichment are well known, less is known about the responses of benthos to such gradients or how benthic and pelagic responses may interact. We performed a 9-wk experiment in 2000-L mesocosms in the field to test for the effect of water-column nutrient enrichment on phytoplankton, algae on sediments (epipelon) and hard surfaces (plastic strips), as well as pelagic and benthic primary consumers. The experimental design consisted of 4 nutrient enrichment rates (0, 0.5, 1.0 and 2.0 mu g P L super(-1) d super(-1), together with N to yield an N:P ratio of 20:1 by weight). Nutrient enrichment induced significant increases in chlorophyll a in phytoplankton and attached algae, but not epipelon. Zooplankton biomass was significantly higher in enriched mesocosms than in controls over the initial 4 wk of enrichment, but the effect was not sustained over the course of the experiment. Densities of sediment-dwelling, and hard-substrata-associated invertebrates were higher in enriched treatments relative to controls. Emergence of benthic insects also increased with enrichment. Size and species composition of benthic macroinvertebrates differed between enriched treatments and controls. Our results suggest that nutrients added to the water column were quickly converted into benthic biomass, likely reducing pelagic responses to enrichment.
AN: 4206748
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TI: Geochemical-focusing of manganese in lake sediments - an indicator of deep-water oxygen conditions
AU: Schaller,-T.; Wehrli,-B.
AF: Limnological Res. Cent., Swiss Federal Inst. for Environ. Sci. and Technol. (EAWAG) and Swiss Federal Inst. Technol. (ETH), CH-6047 Kastanienbaum, Switzerland
SO: AQUAT.-GEOCHEM. 1997 vol. 2, no. 4, pp. 359-378
LA: English
ER: F (Freshwater)
AB: The lateral distributions of Mn concentrations in the sediments of two Swiss lakes under varying oxygen conditions have been determined. The comparison of Mn distribution patterns with oxygen in the deep-water provides strong evidence for a geochemical-focusing effect, which is driven by the redox cycle of manganese. Conditions essential for this process to occur are anoxic sediments in contact with oxic deep-water. Average sedimentary manganese concentrations determined for different water-depth ranges are directly proportional to the area of shallower sediments. This result indicates that geochemical-focusing of manganese in lake sediments is a promising proxy indicator for the reconstruction of oxygen conditions during deposition.
AN: 4206661
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TI: Group report: How do upwelling systems vary through time?
AU: Peterson,-L.C.; Abbott,-M.R.; Anderson,-D.M.; Caulet,-J.-P.; Conte,-M.H.; Emeis,-K.-C.; Kemp,-A.E.S.; Summerhayes,-C.P.
CO: Dahlem Workshop on Upwelling in the Ocean: Modern Processes and Ancient Records, Berlin (Germany), 25-30 Sep 1994
SO: UPWELLING-IN-THE-OCEAN:-MODERN-PROCESSES-AND-ANCIENT-RECORDS. Summerhayes,-C.P.;Emeis,-K.-C.;Angel,-M.V.;Smith,-R.L.;Zeitzschel,-B.-eds. JOHN-WILEY-and-SONS no. 18 pp. 285-312
ST: ENVIRON.-SCI.-RES.-REP. 1995 no. 18
LA: English
ER: M (Marine)
AB: Upwelling is a largely wind-driven process by which transfer of momentum from the prevailing wind fields to the surface ocean results in divergence, forcing cool, nutrient-rich subsurface waters up into the photic zone. Upwelling regions are among the most productive environments in the world and serve as both sources and sinks for many biologically active elements. They thus play a major role in the biogeochemical cycling of the oceans. By their very nature, upwelling systems are extremely sensitive to climatic and oceanographic change. In turn, through feedbacks in the carbon cycle, upwelling systems have the potential to influence climate as well. Sediments which underlie the major upwelling centers preserve important information on past variations in the strength and areal extent of upwelling, information of great relevance to studies of global carbon budgets and of the role of this process in climate change. (DBO)
AN: 4205468
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TI: What are upwelling systems contributing to the ocean's carbon and nutrient budgets?
AU: Toggweiler,-J.R.; Carson,-S.
AF: GFDL/NOAA, Princeton Univ., P.O. Box 308, Princeton, NJ 08542, USA
CO: Dahlem Workshop on Upwelling in the Ocean: Modern Processes and Ancient Records, Berlin (Germany), 25-30 Sep 1994
SO: UPWELLING-IN-THE-OCEAN:-MODERN-PROCESSES-AND-ANCIENT-RECORDS. Summerhayes,-C.P.;Emeis,-K.-C.;Angel,-M.V.;Smith,-R.L.;Zeitzschel,-B.-eds. JOHN-WILEY-and-SONS no. 18 pp. 337-360
ST: ENVIRON.-SCI.-RES.-REP. 1995 no. 18
LA: English
ER: M (Marine)
AB: Understanding the effect of upwelling systems on the carbon cycle requires detailed knowledge of how nutrients and carbon enter and leave these systems. In this article we use recent findings of the JGOFS equatorial Pacific process study and a detailed three-dimensional model to look specifically at the nitrate budget in the equatorial Pacific. Nitrate enters the equatorial upwelling system in the far-western Pacific via the Equatorial Undercurrent. Because the equatorial biota tend to recycle nitrogen much more effectively than they export nitrogen in sinking particles, nitrate stocks build up in the eastern Pacific. A significant fraction of the nitrate entering the upwelling system seems to be lost to denitrification in the anoxic zones off Peru and Central America. Through denitrification, the equatorial upwelling system may function as a regulator of global nitrate stocks and air-sea partitioning of CO sub(2). (DBO)
AN: 4205465
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TI: Group report: How do open ocean upwelling systems operate as integrated physical, chemical, and biological systems and influence the geological record?
AU: Angel,-M.V.; Baars,-M.A.; Barber,-R.T.; Chavez,-F.P.; Kastner,-M.; Leinen,-M.; Lutjeharms,-J.R.E.; Reverdin,-G.; Shimmield,-G.B.
CO: Dahlem Workshop on Upwelling in the Ocean: Modern Processes and Ancient Records, Berlin (Germany), 25-30 Sep 1994
SO: UPWELLING-IN-THE-OCEAN:-MODERN-PROCESSES-AND-ANCIENT-RECORDS. Summerhayes,-C.P.;Emeis,-K.-C.;Angel,-M.V.;Smith,-R.L.;Zeitzschel,-B.-eds. JOHN-WILEY-and-SONS no. 18 pp. 193-220
ST: ENVIRON.-SCI.-RES.-REP. 1995 no. 18
LA: English
ER: M (Marine)
AB: For the purposes of our group, we defined upwelling as being organized upward vertical motion, and thus those areas where seasonal mixing dominates the production cycle were excluded from discussion. Our deliberations were centered around five key questions, each of which is discussed in turn below. We conclude our report with a "wish list" for future research. (DBO)
AN: 4205464
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TI: The chemical and biological consequences of coastal upwelling
AU: Hutchings,-L.; Pitcher,-G.C.; Probyn,-T.A.; Bailey,-G.W.
AF: Sea Fish. Res. Inst., Private Bag X2, Rogge Bay 8012, Cape Town, South Africa
CO: Dahlem Workshop on Upwelling in the Ocean: Modern Processes and Ancient Records, Berlin (Germany), 25-30 Sep 1994
SO: UPWELLING-IN-THE-OCEAN:-MODERN-PROCESSES-AND-ANCIENT-RECORDS. Summerhayes,-C.P.;Emeis,-K.-C.;Angel,-M.V.;Smith,-R.L.;Zeitzschel,-B.-eds. JOHN-WILEY-and-SONS no. 18 pp. 65-82
ST: ENVIRON.-SCI.-RES.-REP. 1995 no. 18
LA: English
ER: M (Marine)
AB: The chemical and biological dynamics in coastal upwelling areas are examined from the point of view that pulsed wind events operating at particularly active upwelling sites are responsible for the major injection of new nutrients into the euphotic zone. The rate of supply of new nutrients determines the scope for export to the sediments or fisheries. Inorganic nutrients are removed from the water in a matter of days; however, the sequence and efficiency is dependent on the seed populations and degree of mixing and stratification with more mature water. There is likely to be an optimal frequency of wind events to promote the dominance of large-celled phytoplankton. Mesozooplankton is ill-matched with phytoplankton development with poor grazing control of phytoplankton blooms, and there is considerable microbial activity and sedimentation. The extent of regenerative processes determines whether carbon is exported to the sediments or the atmosphere in upwelling systems. Fish populations in upwelling areas are constrained mostly by suitable areas for reproductive success; the enrichment, retention, and concentration factors are partially exclusive in coastal upwelling regions, resulting in compromise solutions and a high variability in recruitment success. (DBO)
AN: 4205457
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TI: Summer bloom of Gloeotrichia echinulata and Aphanizomenon flos-aquae and phosphorus levels in Antermony Loch, central Scotland
AU: Pitois,-S.G.; Jackson,-M.H.; Wood,-B.J.B.
AF: Environ. Health Div., John Anderson Bldg., Univ. Strathclyde, Glasgow G4 0NG, Scotland, UK
SO: INT.-J.-ENVIRON.-HEALTH-RES. 1997 vol. 7, no. 2, pp. 131-140
LA: English
ER: F (Freshwater)
AB: Nutrient levels (phosphorus and nitrogen) were measured in a small reservoir in Scotland between March 1994 and October 1995. Algae species were identified. Dense blooms of Gloeotrichia echinulata have regularly occurred in late summer in the reservoir for many years, but it did not reach bloom proportions during the 1995 summer and seemed to have been replaced by Aphanizomenon. The bloom of the cyanobacterium Gloeotrichia echinulata that occurred in August 1994 was studied in relation to phosphorus levels present at the time in the water. Results show that the bloom developed after a slight increase in dissolved inorganic phosphorus; while the bloom was developing, particulate inorganic forms of phosphorus increased and were then replaced by particulate organic forms when the bloom reached its maximum density. All phosphorus fractions started to decrease shortly before the bloom collapsed. Our study showed that there did not seem to be any change in the distribution of phosphorus between its different fractions, at least during the first 24 h after collection when the sample was kept in a refrigerator in the dark. We therefore conclude that Gloeotrichia echinulata was probably responsible for transferring phosphorus from the sediments up to the water column in Antermony.
AN: 4204457
153 of 313
TI: Assessing selenium cycling and accumulation in aquatic ecosystems
AU: Bowie,-G.L.; Sanders,-J.G.; Riedel,-G.F.; Gilmour,-C.C.; Breitburg,-D.L.; Cutter,-G.A.; Porcella,-D.B.
AF: Tetra Tech, Inc., 3746 Mt. Diablo Blvd., Suite 300, Lafayette, CA 94549, USA
CO: Int. Clean Water Conf.: Clean Water: Factors That Influence Its Availability, Quality and Its Use, La Jolla, CA (USA), 28-30 Nov 1995
SO: Water,-Air-and-Soil-Pollution 1996 vol. 90, no. 1-2, pp. 93-104
LA: English
ER: F (Freshwater)
AB: We conducted a joint experimental research and modeling study to develop a methodology for assessing selenium (Se) toxicity in aquatic ecosystems. The first phase of the research focused on Se cycling and accumulation. In the laboratory, we measured the rates and mechanisms of accumulation, transformation, and food web transfer of the various chemical forms of Se that occur in freshwater ecosystems. Analytical developments helped define important Se forms. We investigated lower trophic levels (phytoplankton and bacteria) first before proceeding to experiments for each successive trophic component (invertebrates and fish). The lower trophic levels play critical roles in both the biogeochemical cycling and transfer of Se to upper trophic levels. The experimental research provided the scientific basis and rate parameters for a computer simulation model developed in conjunction with the experiments. The model includes components to predict the biogeochemical cycling of Se in the water column and sediments, as well as the accumulation and transformations that occur as Se moves through the food web. The modeled processes include biological uptake, transformation, excretion, and volatilization; oxidation and reduction reactions; adsorption; detrital cycling and decomposition processes; and various physical transport processes within the water body and between the water column and sediments. When applied to a Se-contaminated system (Hyco Reservoir), the model predicted Se dynamics and speciation consistent with existing measurements, and examined both the long-term fate of Se loadings and the major processes and fluxes driving its biogeochemical cycle.
AN: 4204150
154 of 313
TI: Arsenic in central Long Island Sound sediments: Natural levels and cycling patterns
AU: Chaloupka,-K.A.; Aller,-R.C.
AF: Chesapeake Biological Lab, P.O. Box 38, Solomons, MD 20688, USA
CO: Long Island Sound Research Conf.: Is the Sound Getting Better or Worse?, Stony Brook, NY (USA), 30 Sep 1994
SO: PROCEEDINGS-OF-THE-LONG-ISLAND-SOUND-RESEARCH-CONFERENCE:-IS-THE-SOUND-GETTING-BETTER-OR-WORSE? McElroy,-A.;Zeidner,-J.-eds. STONY-BROOK,-NY-USA NEW-YORK-SEA-GRANT-INST. 1995 p.74
RN: NYSGI-W-94-001 (NYSGIW94001)
LA: English
ER: M (Marine)
AB: Arsenic is controlled in the marine environment by redox cycling, organic matter degradation, physical/biological transport, and anthropogenic activity. To evaluate the relative importance of controlling factors in central Long Island Sound, the early diagenetic cycling of arsenic (As) was examined in surficial sediments during the annual spring phytoplankton bloom. Pore water As profiles and reactive solid phase distributions of As associated with metal oxides (defined by an operational leach) demonstrate a dynamic remobilization of As near the sediment water interface. Dissolved As generally increases to a subsurface maximum within the upper few centimeters, while reactive solid As decreases exponentially with depth. Maximum pore water and reactive solid As concentrations range from 0.06 - 0.24 mu M and 70-80 nmol/g respectively. Arsenic appears to be controlled by associations with Fe, Mn, and organic matter (represented by P). Regular relations between As and these elements become weaker as remobilization intensifies with organic loading during the spring bloom. Arsenic remobilization fluxes calculated from diagenetic models of dissolved and solid distributions are 0.02-0.63 mu mol/m super(2)/d and 1.4 - 12 mu mol/m super(2)/d respectively. Results from central Long Island Sound demonstrate that As levels and recycling behavior are comparable to other estuarine systems and that the studied region is not unusually contaminated with respect to total As (DBO).
AN: 4202341
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TI: Acetate cycling in the water column and surface sediment of Long Island Sound following a bloom
AU: Wu,-H.; Scranton,-M.I.
AF: Marine Sciences Research Center, State University of New York at Stony Brook, Stony Brook, NY 11794-5000, USA
CO: Long Island Sound Research Conf.: Is the Sound Getting Better or Worse?, Stony Brook, NY (USA), 30 Sep 1994
SO: PROCEEDINGS-OF-THE-LONG-ISLAND-SOUND-RESEARCH-CONFERENCE:-IS-THE-SOUND-GETTING-BETTER-OR-WORSE? McElroy,-A.;Zeidner,-J.-eds. STONY-BROOK,-NY-USA NEW-YORK-SEA-GRANT-INST. 1995 p.67
RN: NYSGI-W-94-001 (NYSGIW94001)
LA: English
ER: M (Marine)
AB: Organic matter decomposition plays a key role in oxygen depletion in the waters and surface sediments of Long Island Sound (LIS). Rates of acetate cycling are often equivalent to rates of anaerobic decomposition of organic matter. Therefore, the concentration and uptake rate constants of acetate were measured every two to three weeks from early spring to early summer in LIS surface and bottom water, and sediment. Pore water acetate concentrations were measured at intervals of a few millimeters in the near surface sediment revealing a strong depth variation, with a concentration maximum in the surface millimeters. Peaks of acetate concentration seem to be associated with the redox boundary. Acetate uptake rates (rate constant times concentration) in the water column varied from less than 1 nM/L/h in the early spring to tens of nM/L/h in the early summer. In the sediment, acetate uptake rates averaged over the top 6 cm varied from 0.387 mu M/h to similar to 8.9 mu M/h in the early spring following the bloom. Our data suggest that both temperature and the amount of fresh organic matter present in a system may strongly affect the acetate distribution, and that, in turn, acetate cycling rates may be excellent indicators of the remineralization of the most labile fractions of carbon (DBO).
AN: 4202317
156 of 313
TI: Processes of enzymolysis of organic macromolecules at different salinities and their relationship with physiologically important and toxic metals in the littoral zone of the Barents Sea.
OT: Protsessy fermentativnogo gidroliza organicheskikh makromolekul v vode razlichnoj solenosti i ikh vzaimosvya's fiziologicheski vazhnymi i toksichnymi metallami na litorali Barentseva morya
AU: Korneeva,-G.A.; Tropin,-I.V.; Romankevich,-E.A.
AF: IORAN, Moscow, Russia
SO: OKEANOLOGIYA 1997 vol. 37, no. 2, pp. 226-231
LA: Russian
ER: M (Marine)
AB: The paper presents data on the enzymatic hydrolysis of proteins and polysaccharides in natural sea, fresh and mixed waters and analyzes effect of different contents of individual heavy metals and their pairs on the processes of enzymolysis at different salinities.
AN: 4201355
157 of 313
TI: Biogenic silica recycling in surficial sediments across the polar front of the Southern Ocean (Indian Sector)
AU: Rabouille,-C.; Gaillard,-J.-F.; Treguer,-P.; Vincendeau,-M.-A.
AF: Cent. des Faibles Radioactivites, Lab. Mixte CNRS-CEA, Av. de la Terrasse, 91190 Gif sur Yvette, France
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 5, pp. 1151-1176
NT: Special issue: ANTARES 1: France JGOFS.
LA: English
ER: M (Marine)
AB: The processes controlling preservation and recycling of particulate biogenic silica in superficial sediments must be understood before one uses biogenic silica as a proxy in paleo-oceanographic studies, and in order to compute oceanic mass balances for silica. In this respect, the Antarctic Ocean is certainly a key region due to its high productivity and export of biogenic silica. In order to quantify sedimentary fluxes and identify crucial processes that allow the preservation of biogenic silica, pore water and solid phase silica profiles were performed on sediment cores from the Southern Ocean (Indian Sector) during the ANTARES 1 cruise. In combination with solubility data reported by Van Cappellen and Qiu (1997a), a process model representing the early diagenesis of silica was developed. In this model, a dependence with depth of the kinetic constant was introduced to allow the preservation of biogenic silica in sediment porewater undersaturated with respect to that phase. Using this steady-state model, it is proposed that a proportionality of the reactivity of the biogenic silica with its settling flux is necessary to explain the observed profiles. It is then shown using this model that the preservation of biogenic silica is not a linear function of the deposited flux. Using a modified version of this model containing an explicit term of reprecipitation, we hypothesize that reprecipitation alone cannot counterbalance dissolution and that its effect is certainly related to a decrease in either surface solubility or kinetics of dissolution.
AN: 4201296
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TI: Biogenic silica dissolution in sediments of the Southern Ocean. 2. Kinetics
AU: Van-Cappellen,-P.; Qui,-L.
AF: Sch. Earth and Atmos. Sci., Georgia Inst. Technol., Atlanta, GA 30332-0340, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 5, pp. 1129-1149
NT: Special issue: ANTARES 1: France JGOFS.
LA: English
ER: M (Marine)
AB: The dissolution kinetics of biogenic silica in surface sediments collected during the ANTARES I cruise were measured in stirred flow-through reactors. The rate data exhibit a distinctly non-linear dependence on the degree of undersaturation. Near equilibrium, the rates of silica dissolution and precipitation define a single linear trend, i.e. the kinetics are symmetric about the equilibrium point. When the dissolved silica concentration drops below a critical level, however, the dissolution rate rises exponentially with increasing undersaturation. Hence, the data disagree with the linear rate law generally used to describe the dissolution kinetics of biogenic silica. It is hypothesized that the kinetic transition from the linear to the exponential regime represents the onset of localized dissolution centered on surface defects, e.g. small pores and crevices, or compositional defects. The effects of temperature and pH confirm that the critical process controlling the overall dissolution kinetics is the hydrolysis of bridging Si-O-Si bonds at the solid-solution interface. The rate measurements indicate that the reactivity of biogenic silica decreases substantially with depth in the sediment. The decrease in reactivity is explained by a progressive reduction of the defect density of the silica surfaces, through dissolution and reprecipitation of silica. It does not appear to result from the preferential dissolution of a more reactive fraction of biogenic debris deposited from the water column. Surface areas obtained by the N sub(2)-BET method or concentrations of extractable biogenic silica do not provide satisfactory proxies for the reactive surface area of silica in the sediments. However, a positive correlation was observed between the surface reactivity and the exchangeable Co super(2+) adsorption capacity of biogenic silica. Specific kinetic effects on silica dissolution of the aluminum content of the silica surfaces or organic matter coatings were not observed. Both the non-linear dissolution kinetics and the aging of the silica surfaces help restrict the dissolution of deposited biogenic silica to a narrow zone close to the water-sediment interface. The results of the flow-through experiments highlight the importance of in situ early diagenetic processes in controlling the behavior and fate of deposited biogenic silica: no evidence was found supporting a significant effect of differences in solubility or reactivity inherited from the biomineralization process in the water column.
AN: 4201295
159 of 313
TI: Dynamics of DOC in the Norwegian Sea inferred from monthly profiles collected during 3 years at 66 degree N, 2 degree E
AU: Boersheim,-K.Y.; Myklestad,-S.M.
AF: Lab. Biotechnol., Norwegian Univ. Sci. and Technol., N-7034 Trondheim, Norway
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 14, pp. 593-601
LA: English
ER: M (Marine)
AB: Water samples were collected monthly for 3 years at 66 degree N, 2 degree E in the Norwegian Sea, 250 nautical miles off the Norwegian coast. Concentrations of dissolved organic matter were measured with high temperature catalytic oxidation. DOC varied from 53 mu mol C/l to 149 mu mol C/l among all the samples collected. Blank readings from MilliQ water were less than 9.3 mu mol C/l, these values were not subtracted. In the 0-50 m layer DOC concentration was on average 1.2 times greater than in deep water. In the upper 50 m, annual variation was pronounced, with an increase in DOC concentration in spring and summer of variable timing and magnitude, and a less variable decrease in DOC concentration starting in August-September. The rates of increase were in the range 0.16-0.26 mu mol C/l/d. During 1992 we measured a pulse of DOC at depths between 400 and 800 m. The concentration increased consistently at a rate of 0.14-0.16 mu mol/l/day during 1 year. This change presumably was caused by advection, because these waters are well below the photic zone. Within our resolution limit, changes in the deep water from 1000 to 2000 m were hardly detectable and not related to annual cycles.
AN: 4201185
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TI: Oceans
AU: Ittekkot,-V.
SO: CLIMATE-CHANGE-1995-IMPACTS,-ADAPTATIONS-AND-MITIGATION-OF-CLIMATE-CHANGE:-SCIENTIFIC-TECHNICAL-ANALYSES. Watson,-R.T.;Zinyowera,-M.C.;Moss,-R.H.-eds. NEW-YORK,-NY-USA CAMBRIDGE-UNIVERSITY-PRESS 1966 pp. 267-288
LA: English
ER: M (Marine); B (Brackish)
AB: Global warming as projected by Working Group I of the IPCC will have an effect on sea-surface temperature (SST) and sea level. As a consequence, it is likely that ice cover and oceanic circulation will be affected, and the wave climate will change. The expected changes affect global biogeochemical cycles, as well as ecosystem structure and functions, on a wide variety of time and space scales; however, there is uncertainty as to whether extreme events will change in intensity and frequency. We have a high level of confidence that: Redistribution of SST could cause geographical shifts in biota as well as changes in biodiversity, and in polar regions the extinction of some species and proliferation of others. A rise in mean SST in high latitudes should increase the duration of the growing period and the productivity of these regions if light and nutrient conditions remain constant; Sea-level changes will occur from thermal expansion and melting of ice, with regional variations due to dynamic effects resulting from wind and atmospheric pressure patterns, regional ocean density differences, and oceanic circulation; and Changes in the magnitude and temporal pattern of pollutant loading in the coastal ocean will occur as a result of changes in precipitation and runoff.
AN: 4110984
161 of 313
TI: Nutrient regeneration by the zebra mussel (Dreissena polymorpha)
AU: James,-W.F.; Barko,-J.W.; Eakin,-H.L.
AF: US Army Engineer Waterways Experiment Station, Eau Galle Aquatic Ecology Laboratory, Spring Valley, Wisconsin 54767, USA
SO: J.-Freshwat.-Ecol. 1997 vol. 12, no. 2, pp. 209-216
LA: English
ER: F (Freshwater)
AB: Changes in suspended seston and soluble nutrients were examined as a function of zebra mussel (Dreissena polymorpha) density in flow-through sediment-water microcosms to determine impacts on nutrient recycling. Overall, zebra mussels removed > 70% of the suspended seston and > 80% of the total chlorophyll a input to the microcosms. Declines in organic nitrogen in microcosms were accompanied by density-dependent increases in nitrate-nitrite nitrogen. It is suggested that microflora associated with the sediments in the microcosms were transforming ammonium nitrogen, which is an excretory product of zebra mussels, into nitrate nitrogen. Declines in total phosphorus in the microcosms also coincided with density-dependent increases in the concentration of soluble reactive phosphorus and its rate of regeneration, suggesting enhanced nutrient cycling via excretion. Calculated rates of soluble phosphorus regeneration due to zebra mussel activity ranged from 0.3 to 2.5 mg m super(-2) d super(-1) at mussel densities ranging between 170 to 1300 individuals m super(-2).
AN: 4117580
162 of 313
TI: A comparison of benthic foraminiferal paleoproductivity proxies in a sediment core from the NW Africa upwelling area
OT: Foraminiferes benthiques et paleoproductivite: reflexions sur une carotte de l'upwelling (NW africain)
AU: Guichard,-S.; Jorissen,-F.; Bertrand,-P.; Gervais,-A.; Martinez,-P.; Peypouquet,-J.P.; Pujol,-C.; Vergnaud-Grazzini,-C.
AF: Departement de geologie et d'oceanographie, CNRS URA 197, Univ. Bordeaux 1, avenue des Facultes, 33405 Talence cedex, France
SO: C.-R.-Acad.-Sci.-Ser.-2a-Sci.-Terre-Planet.-Earth-Planet.-Sci. 1997 vol. 325, no. 1, pp. 66-70
LA: French
ER: M (Marine)
AB: Two different paleoproductivity proxies, both based on benthic foraminiferal frequency data, are tested in a sediment core from the NW African upwelling area. A first proxy, the BFAR, enables us to estimate the total amount of organic matter introduced into the benthic ecosystem. The second one, the sample scores on the first axis of a P.C.A., enables us to estimate export-paleoproductivity when the oxygen concentration does not exceed 4.4 mL/L. The comparison of these micropaleontological proxies also allows us to evaluate the quality of the organic matter, and thus, to estimate what part of the organic matter introduced in the benthic ecosystem has been remineralized and what part has ultimately been stored in the sediment.
AN: 4117180
163 of 313
TI: Organic geochemistry of marine sediments of the subantarctic Indian Ocean sector: lipid classes - sources and fate
AU: Laureillard,-J.; Pinturier,-L.; Fillaux,-J.; Saliot,-A.
AF: Lab. de Physique et Chimie Marines, Unite de Recherche Associee au CNRS No. 2076, Univ. Pierre et Marie Curie, Case 134, Tour 25-24, 4 Place Jussieu, F-75252 Paris Cedex 05, France
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 5, pp. 1085-1108
NT: Special issue: Antares 1: France JGOFS.
LA: English
ER: M (Marine)
AB: Nine sections of core KTB16 (47 degree 59'98 S, 55 degree 59'74 E, 4240 m) taken from the Indian Ocean sector of the Antarctic Polar Front Zone were analyzed for their lipid class and total chlorin contents using thin-layer chromatography-flame ionisation detection (TLC/FID). The following series were included: hydrocarbons, chlorins and chlorin esters, alcohols, sterols, triacylglycerols, free fatty acids and phospholipids. For these major classes, the distribution of their individual components was determined to evaluate the source and fate of each lipid class. Relationships between the lipid composition of overlying particles and of buried material were investigated. The sediment-water interface was found to be of primary importance in the biogeochemical transformations occurring in organic matter, such as loss of the major part of the lipids, and formation of a notable unresolved complex mixture (UCM), of biological origin. Some classes such as chlorin esters appeared to convey their lipid contents from the upper layers without major alteration. In contrast, several other classes, such as storage lipids, appeared to be degraded during sedimentation, indicating extensive recycling of labile lipids in the water column. The burial efficiency and bacterial inputs downcore were highly variable depending on the class considered. Several novel compounds are reported. They consist of alkyl chlorin esters and include a wide variety of saturated and unsaturated long-chain alcohols. Owing to the lack of lipid data in the study area, these results provide an insight into the various biological and chemical processes occurring in open-sea Antarctic sedimentary environments.
AN: 4114533
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TI: Biogenic silica dissolution in sediments of the Southern Ocean. 1. Solubility
AU: Van-Cappellen,-P.; Qiu,-L.
AF: Sch. Earth and Atmos. Sci., Georgia Inst. Technol., Atlanta, GA 30332-0340, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 5, pp. 1109-1128
NT: Special issue: Antares 1: France JGOFS.
LA: English
ER: M (Marine)
AB: A stirred flow-through reactor technique was used to determine silica solubilities in sediments collected with a multicorer in the Indian sector of the Southern Ocean (ANTARES I cruise). The results show that the apparent silica solubility in the cores may decrease, increase or remain constant with depth. The silica solubility profiles are best explained by the early diagenetic interactions between biogenic silica and soluble aluminum derived from detrital material. By combining the solubility data with measured dissolved silica profiles, it is shown that the variable asymptotic pore water silica levels in the cores cannot be explained solely by differences in silica solubility. In sediments that experience a significant detrital input, the simultaneous reprecipitation of dissolved aluminum and dissolved silica prevents pore water silicic acid from reaching saturation with the dissolving biogenic silica. The principal oceanographic control on pore water silica build-up in the cores studied is the ratio of the deposition fluxes of biogenic silica and detrital material. Solubility differences inherited from the biomineralization process in the surface waters do not appear to have a significant effect on the observed pore water silica levels.
AN: 4114532
165 of 313
TI: Distribution, cycling and mean residence time of super(226)Ra, super(210)Pb and super(210)Po in the Tagus Estuary
AU: Carvalho,-F.P.
AF: Int. At. Energy Agency, Mar. Environ. Lab., P.O. Box 800, MC 98012, Monaco Cedex, Principaute de Monaco
SO: SCI.-TOTAL-ENVIRON. 1997 vol. 196, no. 2, pp. 151-161
LA: English
ER: B (Brackish)
AB: Results for dissolved and particulate super(226)Ra, super(210)Pb and super(210)Po in the Tagus River, estuary and coastal sea system show different distribution and chemical behaviour patterns for these radionuclides in the three aquatic environments. super(226)Ra from riverborne particles dissolves in the estuary and contributes to increased concentrations of dissolved super(226)Ra in estuarine water. In the estuary, dissolved super(210)Pb and super(210)Po from river discharge and atmospheric deposition are scavenged by suspended matter, which in turn becomes enriched in these nuclides in comparison with riverborne particles. As a result of these processes, the estuarine water flowing into the coastal sea contains enhanced concentrations of dissolved super(210)Pb and super(210)Po. Under average river flow conditions, mass balance calculations for dissolved super(210)Po and super(210)Pb in the estuary allowed their mean residence times to be estimated as 18 and 30 days, respectively. Due to the rapid sorption of these radionuclides on to settling particles, bottom sediments in the estuary represent a sink for super(210)Pb and super(210)Po from both natural sources and industrial waste releases. Results also suggest that partial re-dissolution of these radionuclides from bottom sediments and intertidal mudflats is likely to occur in the mid- and low-estuary zones. Nevertheless, box-model computations indicate that the discharge of super(210)Pb and super(210)Po into the coastal sea takes place mainly with the transport of sediment, whereas the discharge in the dissolved fraction can only account for one third of the activities entering the estuary in the soluble phase. Implications of these results to the cycling of radionuclides in phosphate waste releases into estuarine environments are discussed.
AN: 4109561
166 of 313
TI: Fluxes and budgets of contaminants in the German Bight
AU: Suendermann,-J.; Radach,-G.
AF: Zent. Meeres-und Klimaforsch., Univ. Hamburg, Inst. Meereskunde, 22529 Hamburg, Germany
SO: MAR.-POLLUT.-BULL. 1997 vol. 34, no. 6, pp. 395-397
LA: English
ER: M (Marine)
AB: Contaminants in coastal waters such as heavy metals and organochlorines, but also oversupplied nutrients, endanger the marine ecosystem. At the same time, they influence the global cycles of matter in this key region and contribute to global change. In awareness of this essential role, many international and national projects are addressing fluxes and budgets of contaminants in coastal waters. This is especially true for the North Sea where the Quality Status Report of the North Sea is regularly produced as a joint effort of European countries. Nevertheless, our knowledge about regional fluxes, turnover rates and budgets of contaminants as well as their reliability is still in an early stage. These papers contain attempts at budgets for suspended particulate matter (SPM), nitrogen, cadmium, lead and the organochlorines HCH and PCB, as well as the herbicide atrazine, for the German Bight. With respect to SPM, its transport is a priori a natural process without danger for the marine environment. Many contaminants, however, are significantly or mainly transported not in the dissolved but in the particulate phase. This fact determines the importance of SPM fluxes and was the reason for including a chapter on it in these papers. The same is true for the water as a transport vehicle, but its transport rates for different temporal and spatial scales are much better known, so there is no specific chapter for water mass fluxes.
AN: 4109529
167 of 313
TI: Biological roles of trace metals in natural waters
AU: Hunter,-K.A.; Kim,-J.P.; Croot,-P.L.
AF: Dep. Chem., Univ. Otago, P.O. Box 56, Dunedin, New Zealand
CO: 5. Symposium on our Environment [np] [nd]
SO: PROCEEDINGS-OF-THE-5TH-SYMPOSIUM-ON-OUR-ENVIRONMENT. Lee,-H.K.;Wong,-M.K.-eds. 1997 vol. 44, no. 1-3 pp. 103-147
ST: Environmental-Monitoring-and-Assessment vol. 44, no. 1-3
LA: English
ER: M (Marine)
AB: For decades there has been an intense interest in the toxic effects of trace metals on biological organisms in the environment. This period of time has seen increasing improvements in analytical techniques for the measurement and study of trace metals and their subsequent application to a broad spectrum of water systems around the globe. This work has included studies of the geographical distributions of trace metals in different water types in the ocean, the modes of transport and uptake of trace metals and the study of historical changes in trace metal accumulation. Early research highlighted strong similarities in the behaviours of many trace metals and those of well-understood chemical nutrients such as phosphate, nitrate and silicate, known to be essential for phytoplankton growth in the ocean. This suggests that phytoplankton regulate the trace metal composition of seawater for their own benefit. A major achievement in this regard has been the ability to measure, at the sub-nmol/L level, trace metal species that are complexed by naturally-occurring organic ligands of biological origin in ocean waters. It is now clear that the free ion activities of many essential and/or toxic trace metals are regulated by highly specific, strongly complexing ligands exuded by marine phytoplankton. This research encourages a new paradigm in which the growth rates and species composition of primary marine organisms are affected by trace metals at concentration levels orders of magnitude lower than is conventionally believed. As a consequence, the capacity of natural waters to assimilate trace metal-contaminants may be correspondingly much lower than is currently thought reasonable.
AN: 4101665
168 of 313
TI: A balance analysis of phosphorus elimination by artificial calcite precipitation in a stratified hardwater lake
AU: Dittrich,-M.; Dittrich,-T.; Sieber,-I.; Koschel,-R.
AF: Inst. Freshwater Ecol. and Inland Fish., Dep. Stratified Lakes, Alte Fischerhuette 2, D-16775 Neuglobsow, Germany
SO: WATER-RES. 1997 vol. 31, no. 2, pp. 237-248
LA: English
ER: F (Freshwater)
AB: Elimination of phosphorus was achieved by artificial calcite precipitation in the Dagowsee, a stratified eutrophic hardwater lake. The artificial calcite precipitation was induced by hypolimnetic injection of CaO in enclosures during the summer stagnation. The hypolimnetic injection of CaO was combined with aeration for 1 day. The coprecipitation of phosphorus with calcite was shown by energy dispersive X-ray analysis. The content of phosphorus in the calcite was about 0.1 wt%. Phosphorus was homogeneously distributed throughout the precipitated calcite and throughout the calcinated particles of water and sediment. The phosphorus coprecipitation efficiency was calculated from the ratio of the decrease of phosphorus to decrease of calcium in the water according to the House's coprecipitation model.
AN: 4101122
169 of 313
TI: Comparison of Cu and Zn cycling in eutrophic lakes with oxic and anoxic hypolimnion
AU: Xue,-HanBin; Gaechter,-R.; Sigg,-L.
AF: Swiss Fed. Inst. for Environ. Sci. and Technol. (EAWAG), Limnol. Res. Cent., CH-6047 Kastanienbaum, Switzerland
SO: AQUAT.-SCI. 1997 vol. 59, no. 2, pp. 176-189
LA: English
ER: F (Freshwater)
AB: Data on the cycling of Cu and Zn in two eutrophic lakes are presented: Lake Greifen that becomes seasonally anoxic in its hypolimnion and Lake Sempach that is aerated during winter and oxygenated during summer. They suggests that hypolimnetic oxygenation 1) enhances the release of copper from the sediment but 2) also accelerates the entrapment and deposition of Cu and Zn by freshly formed Mn- and Fe-oxides.
AN: 4098574
170 of 313
TI: Patterns of retention and utilization of aerially deposited nitrogen in boreal peatlands
AU: Li,-Yenhung; Vitt,-D.H.
AF: Dep. Biol. Sci., Univ. Alberta, Edmonton, Alberta T6G 2E9, Canada
SO: ECOSCIENCE 1997 vol. 4, no. 1, pp. 106-116
LA: English
ER: F (Freshwater)
AB: Nitrogen dynamics were quantified for two years using super(15)N (as NH sub(4)Cl at 3 g N m super(-2) year super(-1)) in a bog and a rich fen in continental western Canada. After two years, 81-88% of the applied nitrogen was recovered; 98.4-98.7% of the recovered nitrogen occurred in the top 45 cm of the moss-peat layer and 1.3-1.6% occurred in the above ground shrub component. In the bog, 29% was recovered from the top 0-5 cm of Sphagnum fuscum, while in the fen 19% was recovered from this zone in Tomenthypnum nitens. Sphagnum sequestered the applied nitrogen more efficiently than did Tomenthypnum. However, over time Tomenthypnum retained it better in the upper moss layers. Overall, after two years Sphagnum retained 42% and Tomenthypnum 48% in the top 12 cm of the ground layer. The nitrogen of the current year's moss growth contained 26-28% applied nitrogen (% NDFF) after one season and 19-20% after two seasons. Moss production increased from 4-300% annually over the two year period, while production for Betula pumila in the fen and Ledum groenlandicum in the bog did not increase significantly. Decomposition of S. fuscum the bog was significantly less than T. nitens in the fen after two years, but no differences were evident after nitrogen additions in either peatlands. We conclude that 1) nearly all nitrogen is immediately sequestered by the moss layer; 2) much of this new nitrogen is found in the actively growing region and moss production increases; 3) shrubs are little affected by the additional nitrogen during the first two years and direct absorption of nitrogen through leaves is unimportant; and 4) newly deposited nitrogen is tightly controlled by the moss layer in both bogs and fens. However retention patterns are different. Subsequent use of nitrogen by vascular plants is determined by nutrient release through decompositional processes deeper in the moss layer.
AN: 4109060
171 of 313
TI: Manganese flux associated with dissolved and suspended manganese forms in Lake Fukami-ike
AU: Yagi,-A.
AF: Fac. Home Econ., Nagoya Women's Univ., 3-40, Shioji-cho, Mizuho-ku, Nagoya 467, Japan
SO: WATER-RES. 1996 vol. 30, no. 8, pp. 1823-1832
LA: English
ER: F (Freshwater)
AB: Redissolved, particulate and sedimentary manganese were studied in the anoxic hypolimnion of the small monomictic Lake Fukami-ike in central Japan. The amounts of particulate and dissolved manganese in the water column were observed. The release of dissolved manganese starts gradually beginning in March. DMn reaches especially high levels of 93 mgMn m super(-2) d super(-1) from the end of May to the end of June calculated from the gradient of a regression formula for the daily change in DMn. The rate of accumulated PMn is 0.64 mgMn m super(-2) d super(-1) from the end of July calculated from the gradient of a regression formula for the daily change in PMn. An accumulation of PMn and an associated decrease in dissolved organic carbon (DOC) were observed at the transition zone of oxic and anoxic layers. These facts seem to suggest that the DOC decrease involves the consumption of DOC as an electron donor by bacterial catalysis for the reduction of MnO sub(2). The upward and downward DOC fluxes, 0.320 mmolC m super(-2) d super(-1), were calculated by the mean gradient values of the upward and downward DOC concentrations. The mean DOC flux was calculated by the both the mean gradient DOC and the vertical diffusion coefficient (0.0304 m super(-2) d super(-1)). Manganese-reducing bacteria could contribute as much as 24% to the DOC decrease in the oxic and anoxic layers, considering bacterial assimilation efficiency (64%). Vertical diffusion Mn flux from the interstitial water to the hypolimnion is then assumed to be 2 mgMn m super(-2) d super(-1). Mn for the vertical eddy diffusion flux, the vertical diffusion from the interstitial water of the bottom sediment, the sinking flux and microbiological Mn flux were obtained, and the biogeochemical manganese cycle in Lake Fukami-ike was calculated. DMn flux in the oxic and anoxic layers by manganese-reducing bacteria is 0.004 gMn m super(-2) d super(-1), a value corresponding to 10% of DMn flux.
AN: 4105593
172 of 313
TI: Study of marine sulfate-reducing bacterial population using fluorescent in situ hybridization method during decomposing processes of detrital material and polypepton in microcosms
AU: Park,-Young-Tae; Nishimura,-Masahiko; Ohwada,-Kouichi
AF: Dep. Microbiol., Pukyong Natl. Univ., Pusan, Korea
SO: FISH.-SCI. 1997 vol. 63, no. 1, pp. 105-110
LA: English
ER: M (Marine)
AB: Microcosm experiments were performed to know the dynamics of sulfate-reducing bacterial population and volatile fatty acids (VFA) during decomposition of polypepton and detrital material in the surface sediments from Tokyo Bay and Sagami Bay. Population of sulfate-reducing bacteria were detected and counted through fluorescent in situ hybridization with SRB probe which has wide specificity to sulfate-reducing bacterial group, and with Desulfobacter probe which has narrow specificity only to genus Desulfobacter. In the microcosms of the Tokyo Bay sample, vibrioid (0.7-1.0x2-2.5 mu m) and rod (1.5-1.8x2.5-3.5 mu m)shaped SRB were detected on day 3, SRB population changed to cocci(0.7-1.0 mu m) and rod (1.5-1.8x2.5-3.5 mu m) shaped cells on day 8. These rod shaped SRB were hybridized also with Desulfobacter probe. The increase of Desulfobacter followed by the increase of utilized acetate. In the Sagami Bay sample, only rod shaped SRB (0.7-1.2x2.5-6 mu m) was detected on day 35. On day 100, cocci (2-3 mu m) and short rod (0.7-1.2x1.7-2.2 mu m) shaped SRB were detected. No cell was hybridized with Desulfobacter probe. It was considered that there was the succession of sulfate-reducing bacterial population during decomposition of detrital material in the surface sediments. The probe method would be helpful to understand population changes of sulfate-reducing bacteria in the natural bacterial communities.
AN: 4104834
173 of 313
TI: A study of plankton cycles with a parcel-mixed layer model
AU: Xu,-Yongfu; Wang,-Mingxing
AF: LAPC, Inst. Atmos. Phys., Acad. Sin., Beijing 100029, People's Rep. China
SO: MAR.-SCI.-BULL.-HAIYANG-TONGBAO 1996 vol. 15, no. 5, pp. 17-24
LA: Chinese
AB: A simple food web, including plankton (phytoplankton, zooplankton and bacteria) and nonliving nitrogen (detritus, dissolved organic nitrogen, nitrate and ammonium) is used to represent the biological processes taking place in the upper mixed layer of the ocean. This biological model is applied into a parcel of water moving from the Strait of Florida (24 degree N, 80 degree W) to the Norwegian Sea 68 degree N, 10 degree E) in the Extended Gulf Stream System (EGSS) to simulate evolution of plankton and nutrients with time. Results give the life cycle of plankton driven by the nutrients, and also produce the spring bloom. The results are more reasonable than those from the most simple biological model of phytoplankton-zooplankton-nutrient (PZN). On the basis of calculation of various production, the dynamics processes of plankton cycles and their influence factors are further discussed.
AN: 4104753
174 of 313
TI: Sediment trap and global change study
AU: Chen,-Jianfang; Zheng,-Lianfu
AF: 2nd Inst. Oceanogr., SOA, Hangzhou 310012, People's Rep. China
SO: MAR.-SCI.-BULL.-HAIYANG-TONGBAO 1996 vol. 15, no. 1, pp. 41-47
LA: Chinese
AB: Marine particles contain a lot of information on chemical, physical, biological processes in the interior of the ocean. In the last decade, based on time series sediment trap experiments, multidisciplinary researches have been carried out in order to investigate particle flux and composition, their temporal and spatial changes as well as the controlling factors. These studies not only are very useful to answer how marine biogeochemical processes control the atmospheric CO sub(2) variations, but also make a great contribution to understanding the role of ocean in global change.
AN: 4104704
175 of 313
TI: The behavior of dissolved cadmium, copper, lead and their relationship to nutrients in the Ming River Estuary
AU: Zou,-Dongliang; Gao,-Shuying
AF: Dep. Oceanogr., Inst. Subtrop. Oceanol., Xiamen Univ., Xiamen 361005, People's Rep. China
SO: TROP.-OCEANOL.-REDAI-HAIYANG 1996 vol. 15, no. 1, pp. 74-79
LA: Chinese
ER: B (Brackish)
AB: The behavior of dissolved Cd, Cu, Pb and their relationship to nutrients in the Ming River Estuary were studied in June and Oct. 1990. The results indicated additional appearance for Cd, and respectively conservative and removal behavior for Cu and Pb, in June and October. The addition of Cd mainly comes from the remineralization of plankton detritus by microbial activities, whereas Pb removal is dominated by abiotic processes.
AN: 4104613
176 of 313
TI: Size-fractionated phosphate uptake by phytoplankton in West Xiamen Harbour
AU: Huang,-Bangqin; Hong,-Huasheng; Wang,-Haili; Hong,-Liyu
AF: Res. Cent. Environ. Sci., Xiamen Univ., Xiamen 361005, People's Rep. China
SO: J.-OCEANOGR.-TAIWAN-STRAIT-TAIWAN-HAIXIA 1995 vol. 14, no. 3, pp. 269-273
LA: Chinese
ER: M (Marine)
AB: By using carrier-free super(32)P radiotracer method, the study on size- fractionated phosphate uptake rate, rate constant and uptake percentage by phytoplankton was carried out in West Xiamen Harbour. The correlationship among phosphate uptake, standing crop (Chl-a) and photosynthetic rate is discussed. The results indicated that nanophytoplankton (3-20mum) played the most important role in phosphate uptake percentage (74.85%), rate constant (8.28x10 super(-5) /s) and uptake rate [by volume, 5.38x10 super(-5)mumol/(dm super(3).s)] in the three different size phytoplanktons, but in uptake rate (by biomass), picophytoplankton (0.2-3mum) [5.38x10 super(-5)mumol/(mug.s)] was more important than nanophytoplankton [1.79x10 super(-5)mumol /(mumg.s)] and microphytoplankton (20-200mum) [1.14x10 super(-5)mumol /(mug.s)]. The good positive correlationship was found between phosphate uptake percentage with standing crop (Chl-a) and photosynthetic rate, respectively. The study further showed that nanophytoplankton played a key role in phosphorus biogeochemical cycle in West Xiamen Harbour.
AN: 4104351
177 of 313
TI: Bacterial utilization of dissolved humic substances from a freshwater swamp
AU: Bano,-N.; Moran,-M.A.; Hodson,-R.E.
AF: Dep. Mar. Sci., Univ. Georgia, Athens, GA 30602-2206, USA
SO: AQUAT.-MICROB.-ECOL. 1997 vol. 12, no. 3, pp. 233-238
LA: English
ER: F (Freshwater)
AB: Dissolved humic substances from 5 different aquatic habitats in the Okefenokee Swamp, USA, ecosystem were tested for their ability to support growth of natural bacterial communities in batch bioassay experiments. The in situ dissolved organic carbon (DOC) concentration in samples from all sites was high, ranging from 46 to 58 mg Cl super(-1); 63 to 78% of the DOC was humic substances. Humic substances were isolated by adsorption onto Amberlite XAD-8 resin and provided to natural bacterial communities either from the same site or one of the other sites as the only carbon source. Humic substances from all sites supported bacterial growth; generally there were no significant differences among the bacterial communities in the rates or extent of utilization of humic substances. The average specific growth rates of bacteria, determined as changes in biovolume, were 0.026 to 0.044 h super(-1) for all experiments and were comparable to rates measured in situ. The cumulative bacterial carbon production ranged from 58 to 176 mu g Cl super(-1). Based on measures of bacterial carbon production and oxygen consumption, bacterial growth efficiency on humic substances was estimated at 22%, and the percentage of the humic substances pool utilized during the 1 wk bioassay was 0.8 to 1.8%.
AN: 4096635
178 of 313
TI: Transformation of organogenic substances and rates of production - destruction processes in the Okhotsk Sea ecosystem.
OT: Transformatsiya organogennykh veshchestv i skorosti produktsionno-destruktstonnykh protsessov v ehkosisteme Okhotskogo morya
AU: Leonov,-A.V.; Sapozhnikov,-V.V.
AF: Nauchn.-Koordinats, Tsentr 'Kaspij' RAN, Moscow, Russia
SO: OKEANOLOGIYA 1997 vol. 37, no. 1, pp. 67-80
LA: Russian
ER: M (Marine)
AB: The annual dynamics of chemical and biological components in 8 sea areas is reproduced in an ecological model using 1991-1973 observation data on variations in water temperature, surface illumination intensity and water regime characteristics. The model results are used to estimate internal (recycling) and external advection fluxes of organogenic substances (C, N, Si, P, O), and the rates of production - destruction processes in the ecosystem. Biogenic substances accumulated in the surface layer during winter determine primary production in spring. During the summer-autumn period, primary production develops due to recycling of nutrients. In the most productive areas (Kamchatka and Sakhalin coasts), upwelling provides a continuous supply of organogenic substances and creates favourable conditions for phytoplankton development and active biotransformation of the substances. The integral phytoplankton production during the vegetation period is determined by the activity of diatoms (37.6 - 44.6%), peridineans (28.1 - 32.4%) and green algae (27.2 - 30%). The integral phytoplankton production in the surface layer is 59.8 - 66.3% higher than the bacterial destruction of organic matter.
AN: 4095301
179 of 313
TI: On amounts of organic matter buried in marine sediments of marginal seas.
OT: O masshtabakh bassejnovykh 'zakhoronenij' organicheskogo veshchestva v morskikh osadkakh
AU: Kuznetsov,-A.P.; Geodekyan,-A.A.; Marina,-M.M.
AF: IORAN, Moscow, Russia
SO: IZV.-RAN-BIOL. 1997 no. 1, pp. 59-63
LA: Russian
ER: M (Marine)
AB: With particular reference to the Bering Sea, the authors analyze and estimate components of production-destruction biotic balance, contributions of marginal seas to the total amount of organic matter accumulated in ocean sediments, and their oil and gas potentialities.
AN: 4095260
180 of 313
TI: Biogeochemical nutrient cycling in the upper Great Ouse Estuary, Norfolk, U.K.
AU: Sanders,-R.; Klein,-C.; Jickells,-T.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich, Norfolk, UK
SO: ESTUAR.-COAST.-SHELF-SCI. 1997 vol. 44, no. 5, pp. 543-555
LA: English
ER: M (Marine); B (Brackish)
AB: The cycling of dissolved inorganic nutrients in the Great Ouse Estuary, Norfolk, U.K. was studied over a 50-day period in the early summer of 1994. The cycling of nutrients within the estuary and the export of nutrients to the surrounding coastal waters is quantified using mass balancing and conservative mixing considerations. Overall, the estuary was a minor sink for nitrate + nitrite (8%), a modest sink for silicate and phosphate (12 and 22%, respectively), a large source of ammonium (95%), and, overall, a small sink for dissolved inorganic nitrogen (2%). Water-column processes account well for the observed silicon and phosphorus removals; however, sedimentary processes are required to account for most of the ammonium source and some of the nitrate sink. The most significant water-column processes were primary production and nutrient regeneration from particulate material. The former process appears to be driven mainly by nitrogen imported directly at the head of the estuary, not recycled nitrogen. Regenerative processes returned approximately half of the silicate assimilated in primary production to the water column, and reduced the inferred respiratory releases of nitrogen and phosphorus by 40 and 60%, respectively. The two approaches to quantifying export, mass balancing and conservative mixing considerations, complement each other well, with the mixing analysis suggesting magnitudes and locations for nutrient-cycling processes not quantified by the mass-balance model.
AN: 4094599
181 of 313
TI: Spring development of phytoplankton biomass and composition in major water masses of the Atlantic sector of the Southern Ocean
AU: Bathmann,-U.V.; Scharek,-R.; Klaas,-C.; Dubischar,-C.D.; Smetacek,-V.
AF: Alfred-Wegener-Inst. for Polar and Mar. Res., 27515 Bremerhaven, Germany
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 1-2, pp. 51-67
LA: English
ER: M (Marine)
AB: The distribution and composition of phytoplankton stocks in relation to water masses were studied during the SO-JGOFS cruise of R.V. Polarstern in the Atlantic sector of the Southern Ocean in October/November 1992. The cruise comprised one west-to-east transect along the ice edge from 49 degree W to 6 degree W and several meridional transects along 6 degree W that extended from the closed pack ice of the Weddell Sea, across the southern Antarctic Circumpolar Current (ACC) and into the Polar Frontal Zone. Chlorophyll (chl a concentrations, temperature and salinity were recorded continuously in surface water during the transects. Vertical distribution and species composition of microplankton were assessed microscopically in discrete water samples collected at stations. Contrary to expectations, no significant enhancement of phytoplankton biomass was found in the vicinity of the retreating ice cover. Melt-water-influenced zones were indicated by low salinity but also by abundance of characteristic sea-ice species such as Nitzschia closterium and N. prolongatoides, but chlorophyll concentrations averaged only 0.3 mg chl a m super(-3) and barely increased during the spring. Values were even lower and remained constant in the southern ACC (ca 0.2 mg chl a m super(-3)). In contrast, large phytoplankton blooms developed during the 6 weeks of investigation in the region of the Polar Front (PFr), from 0.7 to >4 mg chl a m super(-3). Three distinct blooms extended below 70 m depth, each dominated by a different diatom species (Fragilariopsis kerguelensis, Corethron inerme and C. criophilum). We speculate that the large phytoplankton stocks below 40 m depth are a result of subduction of surface layers as sinking and in situ growth can be ruled out. The factors leading to the accumulation of high phytoplankton stocks in the PFr (up to 270 mg chl m super(-2)), but not in the meltwater zones or in the front between ACC and Weddell Gyre, are not clear, but higher iron concentrations in the former region seem to have played a role.
AN: 4092491
182 of 313
TI: Ecology and biogeochemistry of the Antarctic Circumpolar Current during austral spring: A summary of Southern Ocean JGOFS cruise ANT X/6 of R.V. Polarstern
AU: Smetacek,-V.; De-Baar,-H.J.W.; Bathmann,-U.V.; Lochte,-K.; Rutgers-Van-Der-Loeff,-M.M.
AF: Alfred Wegener Inst. for Polar and Mar. Res., D-27515 Bremerhaven, Germany
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 1-2, pp. 1-21
LA: English
ER: M (Marine)
AB: The R.V. Polarstern cruise ANT X/6, part of the international Southern Ocean JGOFS programme, investigated plankton spring bloom development and its biogeochemical effects in different water masses of the Atlantic sector of the Southern Ocean: the Polar Frontal region (PFr), the southern Antarctic Circumpolar Current zone (sACC), its boundary with the Weddell Gyre (AWB) and the marginal ice zone (MIZ). The relative roles of physical stability, iron limitation and grazing pressure in enhancing or constraining phytoplankton biomass accumulation were examined. Three sections were carried out between the PFr and the ice edge along the 6 degree W meridian from early October to late November 1992. This paper summarises the major findings of the cruise and discusses their implications for our understanding of Southern Ocean ecology and biogeochemistry. A major finding was the negligible build-up of plankton biomass and concomitant absence of CO sub(2) drawdown associated with seasonal retreat of the ice cover. In striking contrast to this unexpected poverty of both the MIZ and the frontal region of the AWB, distinct phytoplankton blooms, dominated by different diatom species, accumulated in the PFr. Chlorophyll stocks in the sACC remained monotonously low throughout the study. Our findings confirm those of other studies that frontal regions are the major productive sites in the Southern Ocean and that input of meltwater and associated ice algae to the surface layer from a retreating ice edge is by itself an insufficient condition for induction of phytoplankton blooms. The blooms in the PFr developed under conditions of shallow mixing layers, high iron concentrations and relatively low grazing pressure. However, in all three blooms, high biomass extended to deeper than 70 m, which cannot be explained by either in situ growth or sinking out of a part of the population from the upper euphotic zone. Subduction of adjoining, shallower layers to explain depth distribution is invoked. Despite a clear CO sub(2) drawdown in the Polar Frontal region, the highly variable conditions encountered render reliable estimation of annual CO sub(2) fluxes in the Southern Ocean difficult.
AN: 4092490
183 of 313
TI: Biogeochemical dynamics and the silicon cycle in the Atlantic sector of the Southern Ocean during austral spring 1992
AU: Queguiner,-B.; Treguer,-P.; Peeken,-I.; Scharek,-R.
AF: UMR CNRS 6539, Inst. Univ. Europeen de la Mer, Univ. de Bretagne Occidentale, BP 809, F-29285 Brest Cedex, France
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 1-2, pp. 69-89
LA: English
ER: M (Marine)
AB: High biogenic silica (BSi) concentrations (maximum: 11.7 mu mol l super(-1)) were recorded during late November at the southern border of the Polar Frontal region (PFr). Position of the BSi maximum at depth suggested the occurrence of a sinking diatom population. By contrast, siliceous biomass was low (BSi <0.6 mu mol l super(-1)) in the Marginal Ice Zone (MIZ) despite a sea-ice retreat of 200 km during the study period. Diatoms released from the receding ice were not actively growing. The Permanently Open Ocean Zone also showed very low BSi biomass (<0.5 mu mol l super(-1)) and appeared as an area where phytoplankton are not dominated by siliceous organisms, especially in its middle part where BSi/POC (particulate organic carbon) molar ratios ranged between 0.04 and 0.06 at 53 degree S, from surface to 200 m depth. At the southern border of the PFZ, the bloom coincided with an area of high lithogenic silica concentrations probably of aeolian origin. In addition, Bsi/POC molar ratios measured in the PFZ were the highest ever recorded in the surface waters of the Southern Ocean (maximum: 1.75). This could be due to the presence of heavily silicified diatoms such as Fragilariopsis kerguelensis or also could reflect the more rapid recycling of POC as compared to BSi. Within the bloom area BSi concentrations were positively correlated to pyrophaeophytin pigments, possibly indicating the occurrence of a senescent diatom population. High concentrations of BSi (>1.5 mu mol Si l super(-1)) extended to 200 m between 49 degree S and 51 degree S. Numerous empty frustules also were observed, suggesting significant sedimentation of siliceous particles between 49 degree S and 51 degree S. Estimates of the BSi production of the Polar Frontal region are derived from super(14)C primary production and appropriate BSi/POC ratios, and implications for the total annual production of BSi for the Southern Ocean are discussed.
AN: 4092482
184 of 313
TI: Particulate barium stocks and oxygen consumption in the Southern Ocean mesopelagic water column during spring and early summer: Relationship with export production
AU: Dehairs,-F.; Shopova,-D.; Ober,-S.; Veth,-C.; Goeyens,-L.
AF: Analytische Chemie, Vrije Univ. Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1997 vol. 44, no. 1-2, pp. 497-516
LA: English
ER: M (Marine)
AB: Particulate barium was analysed in the upper 600 m of the Southern Ocean water column during repeated transects along the 6 degree W meridian in October-November 1992. The transects extended between the northern edge of the Weddell Gyre (57 degree 30'S) in the south to 47 degree S within the Polar Front Zone (PFZ) in the north. From earlier studies, it is known that the largest fraction of Ba in oceanic suspended matter occurs as barite micro-crystals. In the PFZ, an increase in the particulate Ba content in surface waters and at mesopelagic depths can be significant over the investigation period (1 month) and follows the increase of primary production during bloom development. Using an inverse one-dimensional advection-diffusion-consumption model, O sub(2) consumption between the base of the mixed layer and 1000 m was estimated. The shapes of the vertical particulate Ba profiles are very similar to those of calculated O sub(2) consumption rates, emphasizing the close link between organic matter oxidation and Ba-barite release at a mesopelagic depth. For the southern Antarctic Circumpolar Current (ACC), depth-integrated rates of O sub(2) consumption correlate significantly with primary production and mesopelagic particulate Ba concentration. For the PFZ, these relationships are subject to more speculation since this is a region of intense mixing, and the appropriate value of the turbulent diffusion coefficient is uncertain. For the ACC, the observed relationship presents the possibility of defining a transfer function between export production to the mesopelagic depth zone and mesopelagic Ba accumulation. The observed regression between rate of O sub(2) consumption and primary production in the southern ACC suggests that about 10% of the synthesized organic carbon can be oxidized in the upper 1000 m of the water column.
AN: 4092479
185 of 313
TI: A comparison of primary production in stream ecosystems
AU: Lamberti,-G.A.; Steinman,-A.D.
AF: Dep. Biol. Sci., Univ. Notre Dame, Notre Dame, IN 46556, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 95-104
LA: English
ER: F (Freshwater)
AB: The objective of this paper is to identify physical, chemical, and biological variables that might help explain the wide range of primary production observed in streams from a variety of biomes and locations throughout the world. We used regression approaches to search for predictive, statistical relationships that might reveal how aquatic, riparian, and watershed variables are associated with differences in primary production among 30 streams from the original data set for which primary production was measured.
AN: 4091296
186 of 313
TI: Solute transfer across the sediment surface of a eutrophic lake: 1. Porewater profiles from dialysis samplers
AU: Urban,-N.R.; Dinkel,-C.; Wehrli,-B.
AF: Dep. Civ. & Mineral Eng., Michigan Technol. Univ., Houghton, MI 49931, USA
SO: AQUAT.-SCI. 1997 vol. 59, no. 1, pp. 1-25
LA: English
ER: F (Freshwater)
AB: Porewater profiles often are used to identify and quantify important biogeochemical processes occurring in lake sediments. In this study, multiple porewater profiles were obtained from two eutrophic Swiss lakes using porewater equilibrators (peepers) in order to examine spatial and seasonal trends in biogeochemical processes. Variability in profile shapes and concentrations was small on spatial scales of a few meters, but the uncertainty in calculated diffusive fluxes across the sediment surface was, on average, 35%. Focusing of Fe and Mn oxides toward the lake center resulted in systematic increases in porewater concentrations and diffusive fluxes of Fe super(2+) and Mn super(2+) with increasing water depth; these fluxes are postulated to be regulated by the pH-dependent dissolution of reduced-metal phases. Despite higher concentrations of inorganic carbon, NH sub(4) super(+), Si and P in pelagic compared to littoral sites, diffusive fluxes of these substances across the sediment surface increased only slightly or not at all with increasing water depth. Porewater profiles did reveal temporal changes in Fe super(2+), Mn super(2+), Ca super(2+) and Mg super(2+) that were an indirect result of the large, seasonal changes in seston deposition, but no clear seasonal variations were found in diffusive fluxes of nutrients across the sediment surface. The intense mineralization occurring at the sediment surface was not reflected in the porewater profiles nor in the calculated diffusive fluxes. Calculated diffusive fluxes across the sediment surface resulted from decomposition occurring primarily in the top 5-7 cm of sediment. Diffusive fluxes from this subsurface mineralization were equal to the solute release from mineralization occurring at the sediment-water interface. Buried organic matter acts as a memory of previous lake conditons; it will require at least a decade before reductions in nutrient inputs to lakes fully reduce the diffusive fluxes into the lake from the buried reservoir of organic matter.
AN: 4086920
187 of 313
TI: Microorganisms in bottom sediments of Lake Baikal and environmental conditions.
OT: Mikroorganizmy donnykh osadkov oz. Baikal i ehkologicheskie usloviya sredy
AU: Zemskaya,-T.I.; Namsaraev,-B.B.; Parfenova,-V.V.; Khanaeva,-T.A.; Golobokova,-L.P.; Granina,-L.Z.
AF: Limnol. Inst. SO RAN, Irkutsk, Russia
SO: EHKOLOGIYA 1997 no. 1, pp. 40-44
LA: Russian
ER: F (Freshwater)
AB: The paper presents data on the abundance and distribution of microorganisms, participating in the carbon and sulphur cycles, in sediments differing in their lithological, chemical and physical characteristics. The data for 1991-1994 are comparable to those for earlier years, suggesting the stable state of microflora in bottom sediments of Lake Baikal.
AN: 4086483
188 of 313
TI: Empirical relationships for use in global diagenetic models
AU: Middelburg,-J.J.; Soetaert,-K.; Herman,-P.M.J.
AF: Netherlands Inst. Ecol., Cent. for Estuarine and Coastal Ecol., Vierstraat 28, 4401 EA Yerseke, The Netherlands
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 2, pp. 327-344
LA: English
ER: M (Marine)
AB: A database containing published rates of sediment and pore-water transport and biogeochemical transformations has been established to derive empirical predictive equations to calibrate and parameterize global diagenetic models. Rates of sediment accumulation, organic carbon burial, organic matter decomposition via aerobic and anaerobic pathways and bioturbation (in terms of bioturbation coefficients) can be predicted quite well using exponential relationships with water depth as an independent variable. The relationships are corrected for skewness to reduce the bias inherent in the back transformation from a lognormal to an arithmetic estimate. Bioturbation is shown to be the dominant mode of sediment transport in the upper centimeters of oceanic sediments. The derived empirical relationships are combined with bathymetric maps to estimate globally integrated rates of benthic processes. Ocean margin sediments account for about 85% of the materials accumulating in the ocean and about 80-90% of the mineralization in marine sediments.
AN: 4083807
189 of 313
TI: Sediment-water exchange of nitrogen compounds and oxygen in the North Sea
AU: Lohse,-L.
SO: ANNU.-REP.-NETH.-INST.-SEA-RES. 1996 pp. 32-34
LA: English
AB: On a global scale, the importance of continental margins in biogeochemical cycles is large, despite the relatively small area they occupy. Although their area comprises only 8% of the ocean, between 18% and 33% of the global primary production takes place on the shelves. The shallow depth of continental shelf seas ensures that a substantial part of the primary production reaches the sea floor. There, intensive chemical and biological processes modify the composition of the organic material settled. The degradation of particulate organic matter produces a variety of dissolved organic and inorganic compounds, which may be further mineralised, sorbed to the sediment matrix, or diffuse out of the sediment. The current debate focusses on the question whether benthic processes along the continental margin can affect the amount of elements participating in global biogeochemical cycles. Recent literature compilations on global nitrogen fluxes revealed a pronounced imbalance of the present-day ocean. It was demonstrated that the nitrogen-loss (175 to 418) Tg N yr super(-1) strongly exceeded the nitrogen supply (90 to 293 Tg N yr super(-1)). This imbalance was primarily caused by an up-ward revision of denitrification rates in shelf-and deep-ocean sediments, which accounted for 101 and 185 Tg N yr super(-1) of the global sedimentary denitrification rate, respectively. Given the small surface area occupied by shelf sediments the validation of benthic denitrification rates as well as the associated fluxes of other inorganic nitrogen compounds is indispensable. These fluxes are subject to considerable seasonal and spatial variation, since production and deposition of biogenic material on the continental shelf affect benthic nitrogen biogeochemistry. The coupling of denitrification and nitrification received particular attention in this project, since a tight coupling between both processes may lead to a removal of fixed nitrogen from the shelf, thereby counterbalancing eutrophication effects.
AN: 4083296
190 of 313
TI: Biogeochemical control on the flux of trace elements from estuarine sediments: Water column oxygen concentrations and benthic infauna
AU: Riedel,-G.F.; Sanders,-J.G.; Osman,-R.W.
AF: Acad. Nat. Sci., Benedict Estuarine Res. Cent., St. Leonard, MD 20685, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1997 vol. 44, no. 1, pp. 23-38
LA: English
ER: M (Marine); B (Brackish)
AB: Trace element (arsenic, copper and manganese) fluxes between sediment and water were examined for approximately 2 months in replicated sediment/water microcosms. Treatments consisted of three oxygen levels in the water column (saturated, 10% saturation and anaerobic) and three different organism treatments (control, Macoma balthica and Nereis succinea). Both arsenic and manganese were released from the sediment in the anoxic treatment, while copper was lost from the water. With the water column either saturated or at 10% oxygen saturation, both arsenic and manganese fluxes were negligible. In contrast, copper fluxes out of the sediment increased with increasing oxygen concentrations. The effect of organisms on the trace element fluxes were greatest immediately after their introduction to the microcosms, and declined substantially thereafter. Nereis caused a substantial initial increase in manganese fluxes, but caused a negative flux (out of the water column) for arsenic. Macoma had a much smaller effect on flux than Nereis. Neither organism had a substantial effect on copper fluxes. Porewater profiles gave good predictions of arsenic and manganese fluxes in the anoxic treatment, but not in the 10% or saturated-oxygen treatments. Porewater profiles underestimated copper fluxes in the oxygenated treatments somewhat, and predicted copper flux in the opposite direction in the anoxic treatment. These results suggest that the annual cycle of anoxia in systems like Chesapeake Bay, and the resulting annual cycle of organism death and recruitment, can significantly alter the cycling of trace elements between the sediment and water column.
AN: 4082901
191 of 313
TI: The use of mass balance investigations in the study of the biogeochemical cycle of sulfur
AU: Evans,-H.E.; Dillon,-P.J.; Molot,-L.A.
AF: RODA Environ. Res., PO Box 447, Lakefield, Ontario K0L 2H0, Canada
SO: HYDROL.-PROCESS. 1997 vol. 11, no. 7, pp. 765-782
NT: Special issue: Geochemical mass balance.
LA: English
ER: F (Freshwater)
AB: The use of mass balances in the investigation of the biogeochemical cycle of sulfur is reviewed for three systems: 1) upland catchments, 2) wetlands, and 3) lakes. In upland catchments, the major inputs of sulfur are via wet and dry atmospheric deposition, whereas outputs or losses occur primarily through volatilization and/or runoff. In addition, sulfur may be stored in vegetation and in the forest floor. In wetlands (particularly peatlands), a large proportion of the sulfur inputs are derived from surface and groundwater originating in the upland system. Because of the fluctuating water table in wetlands, they can act as a source or sink for sulfate, depending on the redox conditions. Wetlands, therefore, can significantly affect input-output budgets for lakes. In most lakes, only a small portion of the sulfate input is retained, (i.e. not lost from the lake via outflow), indicating that there is an excess of sulfate relative to biological needs. Seepage lakes are exceptions to this generalization. Although the reactivity of the sulfate input to many lakes is low, sulfate levels, especially in regions receiving substantial atmospheric sulfur deposition, are high enough that the portion reduced results in substantial in-lake alkalinity production; in fact, in many cases, alkalinity production from sulfate reduction is greater than that resulting from not only other in-lake processes but from external sources (the catchment) as well. The importance of mass balance investigations in elucidating the biogeochemical cycling of sulfur is stressed and the need for additional studies on a whole-system basis stressed.
AN: 4080121
192 of 313
TI: Spatial and temporal response of stream bacteria to sources of dissolved organic carbon in a blackwater stream system
AU: Koetsier,-P.,III; McArthur,-J.V.; Leff,-L.G.
AF: Savannah River Ecology Laboratory, Division of Wetland Ecology, PO Drawer E, Aiken, SC 29802, USA
SO: FRESHWAT.-BIOL. 1997 vol. 37, no. 1, pp. 79-89
LA: English
ER: F (Freshwater)
AB: Spatial differences were examined in assemblage growth by culturing bacteria sampled along the stream continuum on gradient plates using leachates from four common riparian species (Taxodium distichum, Carya spp., Acer rubrum and Decumaria barbara). Bacteria from the lowest site were able to use all sources provided and at all concentrations, whereas bacteria from upper reaches could not. Colony density was correlated to relative leachate concentration at all sites along the continuum. Leachates from fresh and senescent A.rubrum leaves were used to determine temporal differences. Winter assemblages of bacteria could not grow on fresh leaf leachate at any concentration but grew well on autumn leaf leachate at higher concentrations. Differential response of bacterial assemblages indicated local adaptation to potential sources of dissolved organic matter. Growth response of stream bacterial colonies appeared to be dependent on the timing and source of leachate as well as on sources of dissolved organic carbon from further upstream. Growth of bacterial assemblages exhibited 'generalist' characteristics in headwater reaches and 'specialist' characteristics at the mouth of our study stream drainage.
AN: 4079152
193 of 313
TI: The lipid composition of the coccolithophore Emiliania huxleyi and its possible ecophysiological significance
AU: Pond,-D.W.; Harris,-R.P.
AF: Plymouth Marine Laboratory, Prospect Place, Plymouth, UK
SO: J.-MAR.-BIOL.-ASSOC.-U.K. 1996 vol. 76, no. 3, pp. 579-594
LA: English
ER: M (Marine)
AB: The lipid class and fatty acid composition of eight geographically disperse isolates of Emiliania huxleyi, grown under 12 h L:D cycles and harvested during logarithmic and stationary growth phases, were examined. Cell size and chlorophyll content tended to decrease from logarithmic to stationary growth phase. Methyl and ethyl ketones were the dominant lipid classes, although proportions exhibited no clear pattern either between strains or growth phases. Neutral lipid hardly accumulated over the course of the growth experiments, and triacylglycerol was either absent or only present at low levels. In all trains with the exception of a South African isolate, levels of total fatty acid per cell decreased markedly between logarithmic and stationary phases, primarily attributable to reductions in the levels of saturated and monounsaturated fatty acids. Major fatty acids in all strains during both growth phases were 14:0, 16:0, 18:1 (n-9), 18:4 (n-3), 18:5 (n-3) and 22:6 (n-3). Although all strains were rich in polyunsaturated fatty acids (47-72% of total fatty acids) stationary phase cultures consistently contained the highest proportions. The polyunsaturated fatty acid docosahexanoic acid (22:6, n-3) was the most abundant fatty acid in all strains, comprising a maximum of 38.4% of total fatty acids in strain M181 during stationary phase. Multivariate analysis (PCA) allowed logarithmic and stationary phase cultures to be distinguished although no obvious intra-isolate variability was apparent. The results are discussed in terms of the importance of lipids for the ecophysiology of E. huxleyi and the role of this dominant coccolithophore in the marine food chain.
AN: 4079120
194 of 313
TI: Freshwater outflow and Subtropical Convergence influence on phytoplankton biomass on the southern Brazilian continental shelf
AU: Ciotti,-A.M.; Odebrecht,-C.; Fillmann,-G.; Moeller,-O.O.,Jr
AF: Department of Oceanography, Dalhousie University, Halifax, N.S., Cananda
SO: CONT.-SHELF-RES. 1995 vol. 15, no. 14, pp. 1737-1756
LA: English
ER: M (Marine)
AB: The present study discusses the role of different continental shelf water masses on inorganic nutrient levels and on phytoplankton biomass along the southern Brazilian coast during October 1987 and September 1988. In this productive area, variability of phytoplankton biomass has been related to the seasonal latitudinal displacement of the Subtropical Convergence and to the freshwater outflow of La Plata River and Patos Lagoon. Very distinct precipitation rates, as a consequence of the ENSO (El Nino-Southern Oscillation) cycle, preceding the two sampled periods of this study, allowed a first evaluation of the impact of this event on freshwater outflow and shelf phytoplankton biomass. The amount of chlorophyll in shelf waters was directly related to nutrients supplied by the Coastal Water (i.e. freshwater outflow), Subtropical and Subantarctic Waters. Comparing the results of this study with previous cruises performed in the area, it was found that high chl a concentrations are common features during periods of elevated precipitation rates. Apart from nutrient input by freshwater and the consequent changes in the vertical profiles of density, the extreme precipitation rates are also associated with different wind patterns, which, in turn, control the presence of particular water masses in the euphotic zone. Our results suggest that ENSO events have an important impact on the variability of phytoplankton production, and thus should affect biogeochemical cycles in the southern Brazilian coastal areas.
AN: 4079096
195 of 313
TI: Intraspecific stoichiometric variability and the ratio of nitrogen to phosphorus resupplied by zooplankton
AU: Carrillo,-P.; Reche,-I.; Cruz-Pizarro,-L.
AF: Departamento de Biologia Animal y Ecologia, Facultad de Ciencias, 18071 Granada, Spain
SO: FRESHWAT.-BIOL. 1996 vol. 36, no. 2, pp. 363-374
LA: English
ER: F (Freshwater)
AB: An in situ experiment was carried out in a high-mountain oligotrophic lake to quantify the specific release rates of ammonium and phosphorus in different phases of the seasonal succession of plankton. The zooplankton community was dominated by the calanoid copepod Mixodiaptomus laciniatus. The rates of release of N and P and the N:P released ratio fell within the range typical of oligotrophic lakes dominated by copepodite assemblages. The values of the zooplankton N:P ratio (5:1 to 10:1 by weight) were lower than those established for other species of calanoids, and followed a well-established pattern of seasonal variation from year to year with higher values after ice thaw and lower values as individual size increased. The elemental composition of the zooplankton depended on individual size while the released N:P ratio was inversely related to the N:P ration of the food. A feedback regulation was established between the stoichiometric composition of the zooplankton, their food and the released N:P ratio that can help explain changes in pelagic community structure during the ice-free period.
AN: 4078980
196 of 313
TI: Spatial and temporal variation of microbial respiration rates in a blackwater stream
AU: Fuss,-C.L.; Smock,-L.A.
AF: Department of Biology, Virginia Commonwealth University, Richmond, VA 23284-2012, USA
SO: FRESHWAT.-BIOL. 1996 vol. 36, no. 2, pp. 339-349
LA: English
ER: F (Freshwater)
AB: The extent of spatial and temporal variation of microbial respiration was determined in a first-order, sand-bottomed, blackwater stream on the coastal plain of south-eastern Virginia, U.S.A. Annual mean respiration rates (as g O sub(2) m super(-3) h super(-1)) differed significantly among substrata: Leaf litter, 12.9; woody debris, 2.4; surface sediment, 0.8; hyporheic sediment, 0.4; water column, 0.003. Rates associated with wood were higher than those with leaves when expressed per unit surface area. Highest respiration rates on leaves, wood and in the water column occurred during the summer, whereas rates in the sediments, were greatest during the late autumn and winter. Water temperature, as well as particulate organic matter and nitrogen content of the substrata, was correlated positively with respiration rates. Seventy per cent of respiration in the stream occurred in the hyporheic zone, 8-13% occurred in the surface sediment, leaf litter or woody debris, and less than 1% in the water column. Approximately 16% of total detritus, or 40% of non-woody detritus, stored in the stream during the year was lost to microbial respiration.
AN: 4078978
197 of 313
TI: Absence or masking of metabolic fractionations of super(13)C in a freshwater benthic food web
AU: France,-R.L.
AF: Department of Biology, McGill University, 1205 Ave. Dr Penfield, Montreal, Quebec H3A 1B1, Canada
SO: FRESHWAT.-BIOL. 1996 vol. 36, no. 1, pp. 1-6
LA: English
ER: F (Freshwater)
AB: Although marine research has indicated that metabolic fractionations of super(13)C due to differences in organismal trophic position and proximal composition can complicate the isotopic interpretation of energy flow pathways, such potentially confounding problems have never been examined in freshwater benthic food webs. The delta super(13)C values of animals comprising a littoral benthic food web composited from four Canadian Shield lakes showed no relation with either individual trophic position ( delta super(15)N) or lipid content (C/N ratios). Differences in the relative incorporation of autochthonous and allochthonous energy sources by freshwater benthic organisms will alter their delta super(13)C and delta super(15)N values, thereby masking any possibility of observing super(13)C enrichment.
AN: 4078953
198 of 313
TI: Spatial and temporal variability of benthic silica fluxes in the southeastern North Sea
AU: Gehlen,-M.; Malschaert,-H.; Van-Raaphorst,-W.R.
AF: Centre des Faibles Radioactivites, CNRS-CEA, Av. de la Terrasse, F-91190 Gif sur Yvette, France
SO: CONT.-SHELF-RES. 1995 vol. 15, no. 13, pp. 1675-1696
LA: English
ER: M (Marine)
AB: Sediment-water exchange fluxes and pore water profiles of Si(OH) sub(4) were determined in August 1991 and February 1992 for a total of 16 stations located along the northeastward transport path of organic matter in the North Sea. The shape of Si(OH) sub(4) profiles indicated that at several stations mass transport is controlled by turbulent diffusion induced by wave and current mixing in the upper, perturbated centimetres of the sedimentary column. The spatial distribution of silica effluxes clearly reflected the depositional environment, with highest exchange rates linked to areas of recent deposition. Outside the main deposition areas, transient deposition of fresh planktonic material is a key process in explaining observed silica effluxes. The temporal variability of silica effluxes followed the annual cycle of pelagic primary production. During August 1991, measured fluxes ranged from 0.18 to 8.90 mmoles Si m super(-2) day super(-1). Fluxes obtained during February 1992 were decreased by a factor between 2 and 8. Fluxes measured before and after inactivation of fauna with N sub(2)-flushing permitted an estimation of the bioirrigation to be made. The latter accounted for an enhancement of solute exchange ranging from 1.1 to 3.4.
AN: 4078931
199 of 313
TI: Decomposition and recycling of organic matter in muds of the Gulf of Papua, northern Coral Sea
AU: Alongi,-D.M.
AF: Australian Institute of Marine Science, PMB No.3, Townsville M.C., Queensland 4810, Australia
SO: CONT.-SHELF-RES. 1995 vol. 15, no. 11-12, pp. 1319-1337
LA: English
ER: M (Marine)
AB: Most sediment and organic material transported from rivers of southern Papua New Guinea enters into the Gulf of Papua, depositing on the inner shelf as either laminated or bioturbated, silt-dominated mud. These facies are the major trawling grounds for a growing penaeid prawn fishery. In contrast to most other terrigenous shelf deposits, decomposition processes in the upper 20 cm of these Papuan silts are apparently dominated by oxic and suboxic diagenesis. Rates of surface oxygen consumption were high (mean = 26.9; range = 17.8-46.8 mmol O sub(2) m super(-2) d super(-1)) as were bacterial numbers (range: 1-4 x 10 super(10) cells g super(-1) DW) and rates of bacterial carbon production (tritiated thymidine uptake; range; 3-10 gCm super(-2) d super(-1)). Rates of sulfate reduction were low (range: 3.6-6.8 mmol S m super(-2) d super(-1)) with little (18-25%) of the total reduced super(35)SO sub(4) recovered as acid-volatile sulfide. Free sulfides were not detected in porewaters. Total solid-phase S concentrations were low (0.15-0.20% DW) indicating low net S precipitation in the upper 20 cm. Concentrations of dissolved Fe and Mn were elevated in porewaters in the laminated silts. Solid-phase Fe concentrations were moderately high (range: 4.6-5.3% DW) and measured dissolved metal and nutrient fluxes suggest active Fe and Mn reduction (at some stations) and generally high turnover of the porewater N pools. The domination of oxidants other than sulphate and probable C limitation in these moderately Fe-rich silts, results in a S/C signature comparable to freshwater sediments. These diagenetic patterns are reminiscent of those measured in muds on the Amazon shelf and may similarly be attributed to dilution of reactive organic matter combined with intense physical reworking and/or bioturbation, promoting oxidant recharge and favoring decomposition processes other than sulfate reduction. Rapid rates of detrital decomposition lead to fast rates of benthic nutrient release that contribute, on average, 71% and 35% of the daily N and P requirements of shelf phytoplankton production. This close benthic-pelagic coupling may serve to maintain the penaeid prawn fishery in the Gulf of Papua.
AN: 4078889
200 of 313
TI: A preliminary study of carbon system in the East China Sea
AU: Tsunogai,-Shizuo; Watanabe,-Shuichi; Nakamura,-Junya; Ono,-Tsuneo; Sato,-Tetsuro
AF: Lab. Mar. and Atmospheric Geochem., Grad. Sch. Environ. Earth Sci., Hokkaido Univ, Sapporo, Hokkaido 060, Japan
SO: J.-OCEANOGR. 1997 vol. 53, no. 1, pp. 9-17
LA: English
ER: M (Marine)
AB: In the central part of the East China Sea, the activity of CO sub(2) in the surface water and total carbonate, pH and alkalinity in the water column were determined in winter and autumn of 1993. The activity of CO sub(2) in the continental shelf water was about 50 ppm lower than that of surface air. This decrease corresponds to the absorption of about 40 gC/m super(2)/yr of atmospheric CO sub(2) in the coastal zone or 1 GtC/yr in the global continental shelf, if this rate is applicable to entire coastal seas. The normalized total carbonate contents were higher in the water near the coast and near the bottom. This increase toward the bottom may be due to the organic matter deposited on the bottom. This conclusion is supported by the distribution of pH. The normalized alkalinity distribution also showed higher values in the near-coast water, but in the surface water, indicating the supply of bicarbonate from river water. The residence time of the East China Sea water, including the Yellow Sea water, has been calculated to be about 0.8 yr from the excess alkalinity and the alkalinity input. Using this residence time and the excess carbonate, we can estimate that the amount of dissolved carbonate transported from the coastal zone to the oceanic basin is about 70 gC/m super(2)/yr or 2 GtC/yr/area-of-global-continental-shelf. This also means that the rivers transport carbon to the oceans at a rate of 30 gC/m super(2)/yr of the coastal sea or 0.8 GtC/yr/area-of-global shelf, the carbon consisting of dissolved inorganic carbonate and terrestrial organic carbon decomposed on the continental shelf.
AN: 4078732
201 of 313
TI: Dynamics of millenary organic deposits resulting from the growth of the Mediterranean seagrass Posidonia oceanica
AU: Mateo,-M.A.; Romero,-J.; Perez,-M.; Littler,-M.M.; Littler,-D.S.
AF: Netherlands Inst. Ecol., Vierstraat 28, 4401 EA Yerseke, The Netherlands
SO: ESTUAR.-COAST.-SHELF-SCI. 1997 vol. 44, no. 1, pp. 103-110
LA: English
ER: M (Marine); B (Brackish)
AB: The Mediterranean seagrass Posidonia oceanica accumulates large quantities of organic debris as roots, rhizomes and leaf sheaths are progressively buried forming a bioconstruction called 'matte'. The organic material remains with little morphological alteration for millennia. Several strata from these accumulations in various P. oceanica meadows were sampled. Radiocarbon dating of samples yielded a range of 0-3370 years before present. From these data, accretion rates averaging 0.175 cm year super(-1) (range: 0.061-0.414) were inferred. Significant differences between sites were found. Accretion rates showed significant differences between matte strata (i.e. with time), but no defined patterns were appreciated. Such differences were not coherent across sites. It is concluded that accretion rates are mainly controlled by local factors. Analysis of carbon, nitrogen and phosphorous in the organic debris showed that there was not a net release during the process of matte construction; in some sites, nitrogen and phosphorus concentration remained constant throughout the matte profile, while in the other sites, their concentration increased significantly with age. This confirms the role of P. oceanica meadows as sinks for biogenic elements.
AN: 4075947
202 of 313
TI: Stoichiometry of some marine planktonic crustaceans
AU: Gismervik,-I.
AF: Univ. Oslo, Dep. Biol., Sect. Mar. Chem. and Mar. Zool., PO Box 1064, Blindern, N-0316 Oslo, Norway
SO: J.-PLANKTON-RES. 1997 vol. 19, no. 2, pp. 279-285
LA: English
ER: M (Marine)
AB: Atomic C:N ratios in calanoid copepods were generally below the Redfield ratio (6.6), except for the fifth copepodid stage of Calanus sp. The C:P ratios in copepods were generally close to, or higher than the Redfield ratio of 106, but low C:P ratios were found in Acartia clausi (63 plus or minus 7) and in the cladocerans (Podon sp.: 34 plus or minus 5 and Evadne sp.: 59 plus or minus 22).
AN: 4075939
203 of 313
TI: A regional analysis of the physical characteristics of streams
AU: Webster,-J.R.; D'-Angelo,-D.J.
AF: Dep. Biol., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA 24061, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 87-95
LA: English
ER: F (Freshwater)
AB: Physical characteristics of streams are determined by complex interactions between climate and geology, often indirectly mediated by vegetation. These characteristics vary considerably among regions of the world. For example, Wolman and Gerson suggested that stream geomorphology is driven by the frequency of extreme events and the timing and capacity for recovery. In temperate regions, extreme storms and floods that scour and widen the stream channel typically occur at 50- to 200-y intervals. Time between events may therefore be long enough for stream flow, vegetation, and hillslope slumps to return the channel to pre-storm widths. In contrast, arid regions experience severe flooding more frequently. With little time between floods, slow vegetation growth, and often no flow at all between floods, these arid land channels tend to widen to a greater extent than streams in temperate regions. Interactions of climate and geology with their effects on vegetation and physical stream characteristics are the prime determinants of organic processes occurring in streams. In this chapter we describe and compare 8 physical characteristics of the 35 streams described in the preceding chapters. Because of the limited geographic extent of the streams, this analysis is not a comprehensive treatment of the physical characteristics of streams. The primary purpose of this paper is to provide a background for the analyses of organic matter processes presented in subsequent chapters.
AN: 4071916
204 of 313
TI: Organic matter dynamics in Buzzards Branch, a blackwater stream in Virginia, USA
AU: Smock,-L.A.
AF: Dep. Biol., Virginia Commonwealth Univ., Richmond, VA 23284, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 54-58
LA: English
ER: F (Freshwater)
AB: Buzzards Branch is a 1st-order blackwater stream in Surry County, Virginia, USA (37 degree 05'N, 77 degree 03'W). The stream is a tributary of Otterdam Swamp Creek, which is part of the Blackwater River system in the Coastal Plain physiographic province of southeastern Virginia. The stream has characteristics typical of many streams throughout the southeastern Coastal Plain, including low gradient, loose sand sediment, and a well-developed flood plain in its lower reach.
AN: 4071613
205 of 313
TI: Organic matter dynamics in Keppel Creek, southeastern Australia
AU: Treadwell,-S.A.; Campbell,-I.C.; Edwards,-R.T.
AF: Dep. Ecol. and Evolution. Biol., Monash Univ., Clayton, Vic. 3168 Australia
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 58-61
LA: English
ER: F (Freshwater)
AB: Keppel Creek is a 4th-order stream draining 1428 ha of mixed eucalypt forest in the Victorian central highlands in southeastern Australia. Elevation ranges from 400 m to 1200 m. Geology is a mix of ignimbritic rhyodocite and granodiorite and soils are deep, friable mountain loams. Annual precipitation averages 125 cm, some falling as snow, during winter, above 1000 m. Vegetation within the catchment is dominated by mountain ash (Eucalyptus regnans), one of the tallest hardwood trees in the world. Riparian vegetation comprises manna gum (E. viminalis) and messmate stringy bark (E. oblique) with an understorey of blackwood (Acacia melanoxylon), hazel pomaderris (Pomaderris aspera), blanket leaf (Bedfordia arborescens), fishbone water fern (Blechnum nudum), and soft tree fern (Dicksonia antarctica).
AN: 4071612
206 of 313
TI: Organic matter dynamics in the Breitenbach, Germany
AU: Marxsen,-J.; Schmidt,-H.-H.; Fiebig,-D.M.
AF: Limnologische Flussstation des Max-Planck-Instituts fuer Limnologie, D-36110 Schlitz, Germany
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 28-32
LA: English
ER: F (Freshwater)
AB: The Breitenbach is a small, unpolluted 1st-order stream in eastern Hesse (Germany) between the Vogelsberg and Rhoen mountains, 100 km northeast of Frankfurt am Main. Most of the 820-ha catchment was designated a nature reserve in 1990. Early limnological studies were conducted on the stream in the 1960s, but the main thrust of research has been carried out since 1969, when the Breitenbach became the focus of investigations at the Limnological River Station of the Max Planck Institute of Limnology (Limnologische Flussstation des Max-Planck-Instituts fuer Limnologie) in Schlitz. The stream fauna has been studied intensively since this time, and only more recently have aspects such as chemistry, hydrology, bacteria, algae, and POM and DOM dynamics been considered.
AN: 4071611
207 of 313
TI: Organic matter dynamics in 5 subarctic streams, Quebec, Canada
AU: Naiman,-R.J.; Link,-G.L.
AF: Sch. Fish., Box 357980, Univ. Washington, Seattle, WA 98195, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 33-39
LA: English
ER: F (Freshwater)
AB: The 5 principal sites used for these investigations are 25-40 km east of Sept-Iles, Quebec, Canada on the north shore of the Gulf of the St. Lawrence. A full account of these sites, the longitudinal trends as smaller streams coalesce into large rivers, and a summary of changes in organic carbon dynamics and community structure are described by Naiman et al. (1987). This subarctic, Precambrian Shield region is forested with typical boreal species: black and white spruce (Picea mariana and P. glauca; 47% of area), balsam fir (Abies balsamea; 44%), paper birch (Betula papyrifera), trembling aspen (Populus tremuloides), speckled alder (Alnus rugosa), and willow (Salix spp.). There is approximately 112 cm of precipitation annually, evenly distributed throughout the year, with mean monthly values ranging from 8.0 cm in April to 10.6 cm in September and December. Precipitation occurs mostly as snow from October to April. The mean annual temperature is 1 degree C, with a growing season of 105 d (i.e., mean daily air temperature >5.6 degree C). All stream sites are ice-covered from early November to mid April. Most streams are low gradient (<1.5% slope), have high concentrations of DOC (10-15 mg/L), low concentrations of nitrogen (NO sub(3):20-43 mu g/L) and phosphorus (PO sub(4):11-29 mu g/L), and have approximately 2100 degree-days annually ( degree C/y). There is a strong freshet in April and May when 50% of the annual discharge occurs. Minimum flows in January and February are only 3-5% of the annual maximum.
AN: 4071610
208 of 313
TI: Organic matter dynamics in the Kuparuk River, a tundra river in Alaska, USA
AU: Harvey,-C.J.; Peterson,-B.J.; Bowden,-W.B.; Deegan,-L.A.; Finlay,-J.C.; Hershey,-A.E.; Miller,-M.C.
AF: Ecosystems Cent., Mar. Biol. Lab., Woods Hole, MA 02543, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 18-23
LA: English
ER: F (Freshwater)
AB: The Kuparuk River originates in the foothills of the Brooks Range in northern Alaska, USA, and flows north-northeast into the Arctic Ocean, draining a total area of 8107 km super(2). Since the late 1970s, research has been conducted on the upper 24.6 km of the river (143 km super(2) drainage), from its headwaters to its intersection with the trans-Alaska pipeline and the Dalton Highway. The estimated streambed area of the upper Kuparuk watershed is 4.9 x 10 super(5) m super(2) (mainstem length x 20 m, the mean width at the lowest portion of the study reach). At the highway crossing, the Kuparuk is a 4th-order stream. At its headwaters (elevation 1250 m), the Kuparuk River drains primarily alpine communities that give way to moist tundra communities, dominated by the sedge Eriophorum vaginatum, at lower elevations. Terrestrial plant cover is minimal, with streamside patches of dwarf birches (Betula nana) and willows (Salix spp.) generally less than 1 m high. The 15-km segment of the river immediately upstream of the highway crossing is meandering, with a sinuosity (the ratio of channel length to down-valley distance). The upper Kuparuk is relatively undisturbed by human activity. The entire watershed is underlain with permafrost, which greatly reduces deep seepage.
AN: 4071609
209 of 313
TI: Benthic organic matter storage in streams: Influence of detrital import and export, retention mechanisms, and climate
AU: Jones,-J.B.,Jr.
AF: Dep. Biol. Sci., Univ. Nevada, Las Vegas, 4505 Maryland Pkwy., Las Vegas, NV 89154-4004, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 109-119
LA: English
ER: F (Freshwater)
AB: In lotic ecosystems, BOM is a major energy source for secondary production, influences nutrient cycles, and affects export of DOM and POM. Benthic detritus also influences channel stability and retention characteristics and provides habitat for stream microorganisms, macroinvertebrates and fish. However, in spite of the great importance of BOM to stream ecosystem function, benthic detrital storage is one of the most poorly understood components of stream organic matter budgets. In this synthesis I address questions of how BOM and the factors potentially governing storage vary over a range or spatial scales. BOM data were from streams with varying geomorphologies distributed in a range of biomes with vastly different vegetation characteristics. Data were analyzed by subdividing independent variables into 3 categories, 1) organic matter import and export rates, 2) channel characteristics, and 3) latitude and climate, to determine the best predictors of stream BOM. The results were used to assess how BOM storage is coupled to terrestrial litter production, in-stream primary production, and organic matter retention mechanisms.
AN: 4071608
210 of 313
TI: Large-scale trends for stream benthic respiration
AU: Sinsabaugh,-R.L.
AF: Biol. Dep., Univ. Toledo, Toledo, OH 43606, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 119-131
LA: English
ER: F (Freshwater)
AB: Carbon dioxide is the ultimate product of organic matter processing; the release of one mole of CO sub(2) through respiration represents the dissipation of about 470 kJ of energy. Within streams, benthic respiration rates are proximally controlled by the availability of electron acceptors (e.g., oxygen, nitrate), electron donors (organic matter), and inorganic nutrients. The availability of these substrates is often linked to trophic processes which, in turn, reflect local riparian and geomorphic influences and regional hydrologic and climatic patterns. The consequences of this regulatory hierarchy are that 1) spatial and temporal patterns in respiratory activity can be related to many environmental variables and 2) observed patterns are scale-dependent. Estimating system respiration at a single location requires extensive effort. When comparisons are made among sites, large-scale signals may easily be obscured by finer-scale variation. Even if large-scale patterns are detected, experimental verification of causal mechanisms is a daunting prospect. What makes the effort worth pursuing is the possibility of establishing regression models that can predict long-term continental or global responses in ecosystem process rates from disturbance scenarios. Toward that goal, I analyzed stream benthic respiration rates in relation to stored benthic organic matter, water temperature, primary production and other system variables using data collected from 35 long-term study sites.
AN: 4071607
211 of 313
TI: Dissolved organic matter concentration and flux in streams
AU: Mulholland,-P.J.
AF: Environ. Sci. Div., Oak Ridge Natl. Lab., P.O. Box 2008, Oak Ridge, TN 37831-6036, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 131-141
LA: English
ER: F (Freshwater)
AB: Dissolved organic matter (DOM) in streams is important as an energy resource for food webs, a regulator of nutrient uptake and cycling by heterotrophic microbes, a complexing agent for metals, and a determinant of pH and alkalinity. DOM has been shown to be an important metabolic substrate in some streams, with DOM use contributing significantly to total stream metabolism. Sources of DOM are both the terrestrial watershed and instream processes, such as leaching and decomposition of allochthonous particulate organic matter and release by stream algae. For small streams, the primary site of DOM use is the stream bottom, including the interstitial waters of streambed sediments. In large rivers, the water column may also be an important site for DOM use. In this paper, I focus on the concentrations and flux of DOM in streams whose organic matter budgets are presented in the preceding chapters. My objective is to define the variation in annual average DOM concentrations and flux and to identify what factors might be most responsible for this variation.
AN: 4071606
212 of 313
TI: Organic matter budgets for streams: A synthesis
AU: Webster,-J.R.; Meyer,-J.L.
AF: Dep. Biol., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA 24061, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 141-161
LA: English
ER: F (Freshwater)
AB: Estimating the efficiency of ecological processes has been a goal of ecologists since publication of Lindeman's paper on Cedar Bog Lake. Many different definitions and kinds of ecological efficiencies have been determined in the ensuing years. In an analysis of ecosystem budgets, the most significant efficiency is the overall efficiency with which ecosystems use available energy. Two questions are raised by this statement: 1) How do we quantify "energy available"? and 2) How do we define energy "use"? Calculations of ecosystem efficiencies for streams are further complicated by 2 additional questions: 1) How do we deal with both allochthonous and autochthonous inputs? and 2) How are our calculations affected by the transport of organic materials through and out of streams? Our objective was to use simple organic matter budgets to provide an integrated view of stream ecosystem function.
AN: 4071605
213 of 313
TI: Organic matter dynamics in 3 subarctic streams of interior Alaska, USA
AU: Irons,-J.G.,III; Oswood,-M.W.
AF: Inst. Northern Forest., US Forest Serv., 308 Tanana Dr., Fairbanks, AK 99775, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 23-28
LA: English
ER: F (Freshwater)
AB: The predominant biome in interior Alaska is known as the taiga, or northern boreal forest. In these high latitude forests (about 60 degree N-67 degree N in Alaska), the angle of solar radiation with respect to the land surface is a major factor controlling ecological processes, including those relevant to organic matter dynamics in streams. Sun angle determines mean annual air temperature, which in interior Alaska is about -3.3 degree C. Temperature extremes in this continental climate can range from -50 to +35 degree C. One result of this harsh thermal regime is the presence of permafrost in the colder microclimates. Indeed, much of interior Alaska is in the zone of discontinuous permafrost, in which south-facing slopes are generally permafrost-free, and cold north-facing slopes and poorly drained valley bottoms are generally underlain by permafrost. Soil carbon densities reflect the balance between input (organic matter production) and decomposition. In the cold and often water-saturated soils common at high latitudes, decomposition is reduced and soil carbon may accumulate as peat over very long time periods. Thus there is often a positive relationship between the amount of soil organic matter and the amount of permafrost in a watershed. Permafrost affects the hydrological regimes of subarctic streams. Streams dominated by permafrost are more "flashy" than those that are relatively permafrost-free. Snowmelt runoff is later and greater in a permafrost-dominated basin than snowmelt runoff from a permafrost-free basin. Likewise, peak stormflow discharge from a permafrost-dominated basin is much higher than in a non-permafrost stream; but during rain-free periods and in winter, flow is much lower. This pattern is a result of the flow-paths of precipitation as it travels to the stream. On permafrost-dominated north-facing slopes, precipitation enters the thick organic layer and flows above the permafrost to the stream. On permafrost-free south-facing slopes, precipitation enters the groundwater and is released much more slowly to the stream. Differences in discharge result in different patterns of carbon and sediment flux from basins with differing amounts of permafrost.
AN: 4071604
214 of 313
TI: Comparison of litterfall input to streams
AU: Benfield,-E.F.
AF: Dep. Biol., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA 24061, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 104-108
LA: English
ER: F (Freshwater)
AB: Allochthonous organic matter is an important source of energy for many streams and the major energy source for woodland streams or streams with well developed riparian corridors of vegetation. Litterfall may be defined as allochthonous material entering streams from riparian vegetation. It may include leaves and leaf fragments, floral parts, bark, wood (branches and twigs), cones and nuts, fruits, and other plant parts. Litter may reach streams by direct fall or lateral movement (blowing or sliding down the stream banks). The relative amounts of material reaching streams by these 2 routes vary considerably. The objectives of this chapter are to summarize data on direct fall and lateral movement of litter to streams that were included in the earlier site-description chapters, and to analyze whether patterns of direct litterfall to these streams might be explained.
AN: 4071603
215 of 313
TI: Organic matter dynamics in Bear Brook, Hubbard Brook Experimental Forest, New Hampshire, USA
AU: Findlay,-S.; Likens,-G.E.; Hedin,-L.; Fisher,-S.G.; McDowell,-W.H.
AF: Inst. Ecosystem Stud., Millbrook, NY 12545, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 43-46
LA: English
ER: F (Freshwater)
AB: Bear Brook is a 2nd-order stream at the Hubbard Brook Experimental Forest (HBEF) in the White Mountains of New Hampshire, USA. There has been extensive research on this and other tributaries to Hubbard Brook over the past 30 y and most data used in this synopsis have been published previously. The climate is relatively wet and cool with approximately 123 cm of precipitation fairly evenly distributed throughout the year. The experimental catchments at the HBEF are relatively small; the W6 catchment (upper reach of Bear Brook) is 13.2 ha. Mean annual discharge at the weir is 3.75 L/s with maximum monthly average flows ( similar to 11 L/s) in April of most years. Flow at the weir can approach zero in the period from July through September. For the purposes of this organic matter budget, the reach is from the head of the stream channel ( similar to 500 m above the weir) to the point where it discharges to the main Hubbard Brook. Catchment area at this point is 132 ha.
AN: 4071602
216 of 313
TI: Organic matter dynamics in White Clay Creek, Pennsylvania, USA
AU: Newbold,-J.D.; Bott,-T.L.; Kaplan,-L.A.; Sweeney,-B.W.; Vannote,-R.L.
AF: Stroud Water Res. Cent. Acad. Nat. Sci. Philadelphia, 970 Spencer Rd., Avondale, PA 19311, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 46-50
LA: English
ER: F (Freshwater)
AB: White Clay Creek drains agricultural and wooded land in the Piedmont Province of southeastern Pennsylvania and northern Delaware, joining the Christina River in Delaware near the Christina's discharge to the Delaware Bay. This chapter reports studies in a 725-ha watershed forming the headwaters of the East Branch. Elevations in the study watershed range from 100 m to 164 m. The stream draining the study watershed is 3rd order. The total length of stream channels (orders 1-3) is 12,900 m, and the total streambed area assessed at baseflow is 24,000 m super(2).
AN: 4071601
217 of 313
TI: Organic matter dynamics in Kings Creek, Konza Prairie, Kansas, USA
AU: Gray,-L.J.
AF: Dep. Biol., Ottawa Univ., Ottawa, KS 66067, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 50-54
LA: English
ER: F (Freshwater)
AB: The Kings Creek basin encompasses 1059 ha within the Konza Prairie Research Natural Area, a tallgrass prairie in the Flint Hills Uplands of eastern Kansas, USA. This region consists of ridges and valleys underlain by chert-bearing limestones alternating with softer shales of Permian age. Because of the relatively steep topography and rocky soils characteristic of the region, this grassland has never been plowed. Extensive fractures within the rocks result in numerous springs and seeps along the main channels. Elevation ranges from 338 m to 430 m. Konza Prairie was established as a research facility in 1972 after many years as a cattle ranch. The research area is subdivided into watersheds that are burned at varying frequencies. Overlaid on this design is a grazing experiment with blocks of watersheds designated as ungrazed, grazed by native ungulates (bison, Bos bison), and grazed by domestic cattle. Bison were reintroduced to Konza Prairie in 1987, and cattle grazing returned in 1992.
AN: 4071600
218 of 313
TI: Organic matter dynamics in Rattlesnake Springs, Washington, USA
AU: Cushing,-C.E.
AF: 1610 Woodbury St., Richland, WA 99352, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 39-43
LA: English
ER: F (Freshwater)
AB: The cold desert region in southeastern Washington, USA, where Rattlesnake Springs is located has been botanically characterized as a shrub-steppe. Because of the aridity, the productivity of both plants and animals is relatively low compared with other natural communities. In the early 1800s, the most abundant plant in the watershed was big sagebrush (Artemesia tridentata) with an understory of perennial bunchgrasses, especially Sandberg's bluegrass (Poa sandbergii segunda) and bluebunch wheatgrass (Agropyron spicatum). With European settlement that brought livestock grazing and crop raising, the natural vegetation mosaic was opened to a persistent invasion of alien annuals, especially cheatgrass (Bromus tectorum), which is dominant on fields that were cultivated 40 y ago. Mean annual precipitation is about 14 cm. This chapter presents data on the organic matter budget of Rattlesnake Springs, a small cold desert spring-stream. These data were collected as part of a broader study of primary productivity during 1969-1970.
AN: 4071599
219 of 313
TI: Organic matter dynamics in the Ogeechee River, a blackwater river in Georgia, USA
AU: Meyer,-J.L.; Benke,-A.C.; Edwards,-R.T.; Wallace,-J.B.
AF: Inst. Ecol., Univ. Georgia, Athens, GA 30602, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 82-87
LA: English
ER: F (Freshwater)
AB: The Ogeechee River is a 6th-order river in the coastal plain of Georgia, USA. Most of our studies of this blackwater river were done at a site in Effingham County (32 degree 08'N, 81 degree 25'W), 331 km from the river's source and 63 km from its mouth near Savannah. The river at the study site drains a watershed of 6860 km super(2): 5% in the Piedmont, 95% in the Coastal Plain. Human population in the watershed is primarily rural (12 persons/km super(2)) with permitted point source discharges that total 0.6% of mean annual river discharge. The watershed is primarily in agriculture with forested areas of hardwood and pine, which is extensively harvested. Watershed geology consists of sandy sediments of marine origin deposited on igneous and metamorphic rock. The Ogeechee is one of relatively few rivers of its length in North America with no major dams. There are a few mill ponds in the headwaters, but the main stem escaped damming because of its extremely low gradient (0.0002 m/m at the study site).
AN: 4071594
220 of 313
TI: Organic matter dynamics in Sycamore Creek, a desert stream in Arizona, USA
AU: Jones,-J.B.,Jr.; Schade,-J.D.; Fisher,-S.G.; Grimm,-N.B.
AF: Dep. Biol. Sci., Univ. Nevada-Las Vegas, 4505 Maryland Pkwy., Las Vegas, NV 89154-4004, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 78-82
LA: English
ER: F (Freshwater)
AB: Sycamore Creek is an intermittent Sonoran Desert stream in the Basin and Range Province 32 km northeast of Phoenix, Arizona, USA. The drainage basin (505 km super(2)) varies in elevation from 427 to 2164 m and is composed of igneous and metamorphic rock with shallow overlying soil and unconsolidated sediments. Precipitation in the Sycamore Creek watershed averages only 34 and 58 cm/y in lower and upper elevations, respectively, and nearly all falls as rain. Evapotranspiration is quite high (pan evaporation = 310 cm/y); consequently mean annual discharge from this 5th-order river is only 0.8 m super(3)/s, and on average only 8% of precipitation runs off. Rain at higher elevations in the watershed feeds permanent flow in lower-elevation reaches of Sycamore Creek. High-elevation precipitation recharges aquifers that drain into porous alluvium. Lower-elevation permanent reaches occur where geologic faulting brings impervious bedrock to the surface. Downstream from these "sources," surface flow may exist for a few m to several km before water seeps back into sediments.
AN: 4071593
221 of 313
TI: Organic matter dynamics in Hugh White Creek, Coweeta Hydrologic Laboratory, North Carolina, USA
AU: Webster,-J.R.; Meyer,-J.L.; Wallace,-J.B.; Benfield,-E.F.
AF: Dep. Biol., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA 24061, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 74-78
LA: English
ER: F (Freshwater)
AB: Hugh White Creek is a 2nd-order stream at Coweeta Hydrologic Laboratory in western North Carolina, USA. The 61.1-ha watershed drained by this stream was logged in the early 1900s but has been undisturbed since it became part of the National Forest in 1923, except for the death of one of the dominant forest trees (Castanea dentata) by chestnut blight in the 1930s. The major forest trees are now oaks (Quercus spp.), hickories (Carya spp.), red maple (Acer rubrum), and yellow poplar (Liriodendron tulipifera). Streamside vegetation also has considerable birch (Betula spp.) and dense stands of rhododendron (Rhododendron maximum). The watershed has been used as a reference for hydrologic studies and except for one 3-y period has been continuously gaged since 1937. The stream has been the site of many ecological studies since being chosen as a reference for a clearcut logging experiment in 1975. In addition to measurements made on Hugh White Creek, many other streams at Coweeta have been studied by various researchers, and we have used some data from other streams in this summary. The climate at Coweeta is mild and humid. Mean monthly air temperatures range from 3 degree C (January) to 22 degree C (July). Annual precipitation is 188 cm for the watershed drained by Hugh White Creek. Rainfall occurs fairly evenly throughout the year though is somewhat less probable in autumn. On average 133 storms occur annually. Only 2-10% of annual precipitation occurs as snow.
AN: 4071592
222 of 313
TI: Stream organic matter inputs, storage, and export for Satellite Branch at Coweeta Hydrologic Laboratory, North Carolina, USA
AU: Wallace,-J.B.; Cuffney,-T.F.; Eggert,-S.L.; Whiles,-M.R.
AF: Dep. Entomol., Univ. Georgia, Athens, GA 30602, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 67-73
LA: English
ER: F (Freshwater)
AB: Catchment 55 (C 55) is a forested 7.5-ha area of the Coweeta Hydrologic Laboratory in western North Carolina. The stream draining C 55 has the unofficial name of Satellite Branch. The catchment was established in 1984 to serve as a reference stream for a manipulation of benthic invertebrates in a nearby stream. Most of the Coweeta Basin was logged in the early 1900s prior to purchase by the US Forest Service in 1923. Other than experimental manipulations of several catchments, the area within the Coweeta Experimental Forest has not been cut following acquisition by the Forest Service. Since the 1920s, 2 additional basin-wide disturbances have been the chestnut blight in the 1930s, which destroyed one of the major trees, Castanea dentata (Marsh.), and for 2 y (1961 and 1962) the entire Coweeta Basin was sprayed with DDT to control outbreaks of elm spanworm. Terrestrial vegetation of C 55 consists primarily of mixed hardwood forest. Rhododendron (Rhododendron maxima, L.) forms a dense riparian understory and provides year-round shading of the stream. Catchment size, gradient, discharge, and thermal regime are presented.
AN: 4071591
223 of 313
TI: Organic matter dynamics in the West Fork of Walker Branch, Tennessee, USA
AU: Mulholland,-P.J.
AF: Environ. Sci. Div., Oak Ridge Natl. Lab., P.O. Box 2008, Oak Ridge, TN 37831-6036, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 61-67
LA: English
ER: F (Freshwater)
AB: The West Fork of Walker Branch is a 1st-order stream on the US Department of Energy's Oak Ridge National Environmental Research Park in the Ridge and Valley Province of eastern Tennessee, USA. The 38.4-ha catchment drained by the West Fork and an adjacent 59.1-ha catchment drained by the East Fork of Walker Branch were established as research catchments in 1968 when 120 degree V-notched weirs were installed to continuously monitor streamflow. These catchments have been undisturbed since the US government acquired the Oak Ridge Reservation in 1942. Before that time, the Walker Branch Watershed was inhabited by a few families practicing subsistence agriculture, resulting in some areas of cultivation and pasture. There is no evidence that the entire catchment was clear-cut, although all areas were cut at one time or another. In 1967 2 fires burned a total of 38% of the watershed area, with about 15% burned severely. The forest is currently dominated by oaks (Quercus spp.), hickories (Carya spp.), and red maple (Acer rubrum), with scattered pine (Pinus echinata Mill. and P. virginiana Mill.) on the ridgetops and mesophytic hardwoods (predominantly Liriodendron tulipfera L. and Fagus grandifolia Ehrh.) in protected coves and along the stream.
AN: 4071590
224 of 313
TI: Changes in pH in the eastern Equatorial Pacific across stage 5-6 boundary based on boron isotopes in foraminifera
AU: Sanyal,-A.; Hemming,-N.G.; Broecker,-W.S.
AF: Lamont Doherty Earth Observatory Columbia Univ., Palisades, NY, USA
SO: GLOBAL-BIOGEOCHEM.-CYCLES 1997 vol. 11, no. 1, pp. 125-133
LA: English
ER: M (Marine)
AB: Estimates of paleo-pH for the eastern equatorial Pacific Ocean across the oxygen isotopic stage 5-6 boundary have been made based on the boron isotopic composition of planktonic (Orbulina universa) and benthic (mixed species) foraminifera from core V19-28. The estimated deep ocean pH during the penultimate glacial period was about 0.3 plus or minus 0.1 pH units higher compared to the modern deep ocean. This is consistent with previously estimated deep ocean pH changes across the stage 1-2 boundary in the western equatorial Pacific and tropical Atlantic, thus arguing against the possibility that the benthic foraminifera analyzed to estimate deep ocean pH changes have been significantly affected by anomalous local environment and/or diagenesis. The estimated changes in the deep ocean carbonate chemistry require a decoupling (of several kilometers) between the saturation horizon and the lysocline during the glacial periods. Though such a decoupling could be achieved by enhanced respiration CO sub(2) driven calcite dissolution in sediments during glacial periods, it lacks support from the calcite sedimentary records. The boron isotopic compositions of planktonic foraminifera, on the other hand, indicate no significant pH change in the eastern equatorial Pacific surface ocean during the glacial-interglacial transition. This is inconsistent with an expected higher surface ocean pH during the glacial period due to lower atmospheric pCO sub(2) and is also in contrast with the previously estimated boron isotope based glacial-interglacial pH change of 0.2 plus or minus 0.1 pH units in the western equatorial Pacific and tropical Atlantic. The lack of change in eastern equatorial Pacific surface ocean pH between glacial-interglacial periods could be attributed to less nutrient utilization efficiency and/or enhanced calcite production during glacial periods. Such a decrease in nutrient utilization efficiency and/or increase in calcite production would lead to a greater disequilibrium between the pCO sub(2) of eastern equatorial Pacific surface ocean and that of the atmosphere, making this part of the ocean a greater source of CO sub(2) to the atmosphere during glacial periods compared to today.
AN: 4071171
225 of 313
TI: Changes in extent of phosphorus release in a shallow lake (Lake Grosser Muggelsee; Germany, Berlin) due to climatic factors and load
AU: Kleeberg,-A.; Dudel,-G.E.
AF: Technical University Cottbus, Faculty of Environmental Sciences, Seestr. 45, D-15526 Bad Saarow, Germany
SO: MAR.-GEOL. 1997 vol. 139, no. 1-4, pp. 61-75
LA: English
AB: Based upon biweekly investigations of interstitial and pelagial water parameters as well as sediment phosphorus (P) speciation, the mechanisms important for the summer P release in eutrophic Lake Grosser Muggelsee (Germany) are described. Microbial processes were the driving force of mainly anaerobic and also aerobic P release from iron, reductant-soluble and organic P-rich sediments. For 1992 and 1993, two years of very different runoff characteristics, the extent of P release was indirectly controlled by external factors, including the supply of dissolved oxygen and nitrate via inflow (high runoff), changes in land use (e.g., decreasing nitrogen fertilization), and climatic factors, and it was facilitated by wind-induced rapid changes of stratification and mixing events.
AN: 4070903
226 of 313
TI: Lipid distribution in surface sediments from the eastern Central Arctic Ocean
AU: Schubert,-C.J.; Stein,-R.
AF: Alfred Wegener Institute for Polar, Marine Research, Columbusstrasse, D-27568 Bremerhaven Germany
SO: MAR.-GEOL. 1997 vol. 138, no. 1-2, pp. 11-25
LA: English
AB: During the ARCTIC '91 expedition with RV "Polarstern", numerous short (multicorer) and long cores (kastenlot cores), including surface sediments, were recovered along a transect crossing the eastern part of the Arctic Ocean. In this paper we present data on the concentration and distribution of short- (C17+C19) and long-chain (C27, C29, C31) n-alkanes as well as fatty acids (16:0, 16:1, 18:0, 18:1) in the surface sediments from this transect. These compounds, among others, have been used to distinguish between autochthonous marine organic matter and allochthonous terrigenous organic matter supply. Changes in short-chain n-alkane as well as fatty acid contents of the sediments allow us to distinguish between regions characterized by higher or lower marine productivity. Organic carbon contents of the surface sediments are generally high and vary between 0.3% and 2%. In general, the high organic carbon content of the sediments is derived from a high input of terrigenous organic matter. Marine productivity in the Arctic Ocean is mainly controlled by reduced sea-ice cover which allows a higher production rate of phytoplankton. Regions with a higher marine organic matter content are the area NW of Svalbard, the Yermak Plateau, a part of the Lomonosov Ridge and Makarov Basin, and the Morris Yesup Rise. The pattern of distribution of long-chain n-alkanes in Arctic Ocean surface sediments is mainly controlled by sea-ice and/or direct transport from the adjacent shelf areas, although dilution by turbidites influences the deep basins.
AN: 4070885
227 of 313
TI: Terrestrial carbon storage during the past 200 years: A Monte Carlo analysis of CO sub(2) data from ice core and atmospheric measurements
AU: Bruno,-M.; Joos,-F.
AF: Physics Inst., Univ. Bern, Bern, Switzerland
SO: GLOBAL-BIOGEOCHEM.-CYCLES 1997 vol. 11, no. 1, pp. 111-124
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AN: 4070062
228 of 313
TI: Flux of particulate matter through copepods in the Northeast Water Polynya
AU: Daly,-K.L.
AF: Dep. Ecol. and Evolution. Biol. Univ. Tennessee, Knoxville, TN 37996, USA
CO: Northeast Water Polynya Symp., Helsingor (Denmark), 1-5 May 1995
SO: J.-MAR.-SYST. 1997 vol. 10, no. 1-4, pp. 319-342
LA: English
ER: M (Marine)
AB: Particulate organic carbon (POC) and nitrogen (PON) production by large calanoid copepods was investigated on the Northeast Greenland shelf during August 1992 and May to August 1993. Both Calanus hyperboreus and C. glacialis females, when suspended in seawater collected from the chlorophyll maximum, produced about 40 pellets per day, which contained a carbon and nitrogen content equivalent to 8% and 6% of body carbon, respectively, and 2% of body nitrogen. In experiments, the carbon:nitrogen (C:N) ratio by weight of suspended particulates, C. hyperboreus, and fecal pellets was 6.7, 7.7 and 28.5, respectively. The unusually high C:N ratio for pellets, in part, may be attributed to elevated ratios of > 20 mu m size fractions of particulate organic matter, the size fraction more common in the diet of these large copepods and the fraction dominated by diatoms according to microscopic and pigment data. The implied elevated C:N ratios of large phytoplankton cells were probably due to nitrogen deficiency, as shown by other studies in this region. In addition, female C. hyperboreus appeared to be more efficient in assimilating nitrogen than carbon, which also would have contributed to high C:N ratios in egested pellets. Unfractionated POC concentrations explained 54% of the variability in carbon egestion and 70% of the variability in nitrogen egestion in copepods, whereas copepod body content accounted for little of the variation on the short time scales of the experiments. Carbon egestion by C. hyperboreus was positively correlated with POC concentrations at the depth of the chlorophyll maximum, while nitrogen egestion was negatively correlated with PON concentrations in the euphotic zone. Estimates of potential community egestion rates for the upper water column indicate that copepods represent a major pathway of organic carbon transformation in this Arctic shelf system. On average, copepods may have ingested 45% of the primary production and egested fecal matter equivalent to 20% of the carbon and 12% of the nitrogen particulate flux sedimenting from the surface layer. However, several lines of evidence suggest that pellets were remineralized in the water column and, hence, may have contributed little organic carbon and nitrogen to the benthos.
AN: 4066126
229 of 313
TI: New production along 140 degree W in the Equatorial Pacific during and following the 1992 El Nino event
AU: McCarthy,-J.J.; Garside,-C.; Nevins,-J.L.; Barber,-R.T.
AF: Mus. Comparative Zool., 26 Oxford St., Harvard Univ., Cambridge, MA 02138, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1996 vol. 43, no. 4-6, pp. 1065-1093
NT: Special issue: A U.S. JGOFS Process Study in the Equatorial Pacific. Part 2.
LA: English
ER: M (Marine)
AB: This study was conducted as part of two JGOFS transects along 140 degree W between 12 degree N and 12 degree S during February-March 1992 and August-September 1992. Although its purpose was to investigate seasonal variability in nitrogenous nutrient availability and biological utilization in support of primary production, the occurrence of the 1992 El Nino during the first transect permitted us to compare El Nino and post-El Nino conditions. We had hypothesized that an El Nino-related reduction in upwelling of cold nutrient-rich water would lead to a reduction in surface nutrient concentrations and rates of new and primary production in the vicinity of the equator. However, during the height of the El Nino, NO sub(3) super(-) concentrations from 2 degree N to 7 degree S remained high enough (>2 mu mol kg super(-1)) to preclude nitrogen-limited primary production. Total nitrogen uptake rates measured 6 months after the El Nino were 2.4 times greater than those observed during the El Nino. The mean f-ratio for 2 degree N-2 degree S was slightly lower and less variable (0.06-0.13; x super(-)=0.11) during the El Nino than after (0.08-0.20; x=0.13). Over a broader meridional band (5-7 degree N to 5-8 degree S) f-ratios during the El Nino were similar to values determined in 1988, a non-El Nino year, during the same season. Significantly higher rates of new production with only a small increase in f-ratio in the period following the El Nino may constitute a more prominent feature in the ENSO cycle of equatorial biological production and export than the El Nino event per se.
AN: 4062000
230 of 313
TI: Particulate barium fluxes and their relationships to biological productivity
AU: Dymond,-J.; Collier,-R.
AF: Oregon State Univ., Coll. Oceanic and Atmos. Sci., Corvallis, OR 97331, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1996 vol. 43, no. 4-6, pp. 1283-1308
NT: Special issue: A U.S. JGOFS Process Study in the Equatorial Pacific. Part 2.
LA: English
ER: M (Marine)
AB: To understand better the processes that control the transport of particulate barium through the water column and its preservation in marine sediments, we measured particulate barium fluxes along an equatorial transect at 140 degree W using moored sediment traps. The fluxes of barium correlate strongly with the fluxes of organic carbon; however, this relationship is non-linear - higher carbon fluxes have proportionately less associated barium. As a result we observe spatial and temporal variations of roughly a factor of three in the barium-to-organic carbon ratio. Understanding this variability may help to define the processes that determine the geochemical behavior of Ba in the oceans. Several hypotheses that could influence the flux of Ba and its relationship to organic carbon flux have been proposed: barite formation in barium- and sulfate-enriched microenvironments formed during particle settling; lateral advection of carbon and barium from continental margins; the influence of seawater barium concentration; and Ba scavenging by aluminosilicates. Our study reveals temporal variability in the Ba/C sub(org) values that occurs over timescales of less than one month. Also, depth profiles of carbon and Ba fluxes show that the variability originates at depths less than 1200 m and is conveyed throughout the water column. Both the rapid changes and the upper water column origin of the signals point to upper-ocean biological processes as the predominant cause of the variability in the barium-to-organic carbon ratios. We also observe, however, a 25% increase in Ba flux below 1200 m. The deep sources of Ba could result from barite formation linked to continued organic carbon degradation or from lateral sources of particulate barium. Because the spatial and temporal changes in Ba/C sub(org) values correlated to changes in particulate opal and organic carbon fluxes, ocean ecology appears to have an important influence on barium fluxes. A better understanding of the processes that contribute to the particulate barium flux is needed before the accumulation of barium in marine sediments can be used as a quantitative proxy for ocean productivity.
AN: 4061994
231 of 313
TI: Spatial and temporal variability of total organic carbon along 140 degree W in the Equatorial Pacific Ocean in 1992
AU: Peltzer,-E.T.; Hayward,-N.A.
AF: Mar. Chem. and Geochemistry Dep., Woods Hole Oceanographic Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1996 vol. 43, no. 4-6, pp. 1155-1180
NT: Special issue: A U.S. JGOFS Process Study in the Equatorial Pacific. Part 2.
LA: English
ER: M (Marine)
AB: Total organic carbon (TOC) was analyzed on four transects along 140 degree W in 1992 using a high temperature combustion/discrete injection (HTC/DI) analyzer. For two of the transects, the analyses were conducted on-board ship. Mixed-layer concentrations of organic carbon varied from about 80 mu M C at either end of the transect (12 degree N and 12 degree S) to about 60 mu M C at the equator. Total organic carbon concentrations decreased rapidly below the mixed-layer to about 38-40 mu M C at 1000 m across the transect. Little variation was observed below this depth; deep water concentrations below 2000 m were virtually monotonic at about 36 mu M C. Repeat measurements made on subsequent cruises consistently found the same concentrations at 1000 m or deeper, but substantial variations were observed in the mixed-layer and the upper water column above 400 m depth. Linear mixing models of total organic carbon versus sigma sub( theta ) exhibited zones of organic carbon formation and consumption. TOC was found to be inversely correlated with apparent oxygen utilization (AOU) in the region between the mixed-layer and the oxygen minimum. In the mixed-layer, TOC concentrations varied seasonally.
AN: 4061993
232 of 313
TI: Neutral carbohydrate geochemistry of particulate material in the Central Equatorial Pacific
AU: Hernes,-P.J.; Hedges,-J.I.; Peterson,-M.L.; Wakeham,-S.G.; Lee,-C.
AF: Sch. Oceanogr., Univ. Washington, Box 357940, Seattle, WA 98195-7940, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1996 vol. 43, no. 4-6, pp. 1181-1204
NT: Special issue: A U.S. JGOFS Process Study in the Equatorial Pacific. Part 2.
LA: English
ER: M (Marine)
AB: Neutral carbohydrate compositions were determined for particulate samples from plankton net tows, shallow floating sediment traps, mid-depth and deep moored sediment traps, and sediment cores collected along a north-south transect in the central equatorial Pacific Ocean during the U.S. JGOFS EqPac program. Total neutral carbohydrate depth profiles and patterns along the transect follow essentially the same trends as bulk and organic carbon (OC) fluxes-attenuating with depth, high near the equator and decreasing poleward. OC-normalized total aldose (TCH sub(2)O) yields along the transect and with depth do not show any consistent patterns. It appears that compositional signatures of neutral carbohydrates in sediments are more dependent upon their planktonic source than on any particular diagenetic pathway. Based on weight per cent glucose, comparisons of samples between Survey I (El Nino) and Survey II (non-El Nino) indicate that during Survey I, organic material in the epipelagic zone in the northern hemisphere may have undergone more degradation than organic material in the southeastern hemisphere.
AN: 4061992
233 of 313
TI: Origin and maintenance of a high nitrate condition in the Equatorial Pacific
AU: Chai,-Fei; Lindley,-S.T.; Barber,-R.T.
AF: Dep. Oceanogr., Univ. Maine, Orono, ME 04469-5741, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1996 vol. 43, no. 4-6, pp. 1031-1064
NT: Special issue: A U.S. JGOFS Process Study in the Equatorial Pacific. Part 2.
LA: English
ER: M (Marine)
AB: The physical and biological causes for the equatorial nutrient anomaly were investigated using an ecosystem model embedded within an ocean general circulation model to determine the nitrate budget for the equatorial Pacific Ocean. In the 140 degree W region the effects of mixing on nitrate concentration were small compared to the effects of advection; upwelling and zonal transport to the east in the Equatorial Undercurrent were the major processes in the nitrate budget. At 140 degree W on the equator annual J sub(NO3), the total net physical supply of nitrate to the euphotic layer, was 3.76 mmol m super(-2) day super(-1); the vertical integrated (0-120 m) new production calculated from the ecosystem model was 3.36 mmol m super(-2) day super(-1) or, in carbon units, 22.26 mmol C m super(-2) day super(-1). The vertical supply of nitrate (-w partial differential NO sub(3)/ partial differential z) due to the upwelling is controlled by two factors, the vertical velocity and vertical gradient of nitrate concentration. The vertical velocity reaches the maximum during climatological fall, but the vertical gradient of nitrate is weaker in the fall. Therefore, the vertical supply of nitrate is smaller than in spring. To investigate the role of physiological limitation of phytoplankton photosynthesis and specific growth rate on the maintenance of the high nutrient-low chlorophyll (HNLC) condition, a model experiment was performed that included, unchanged from previous model runs, the physical conditions and density-dependent grazing function, but greatly reduced physiological limitations by increasing alpha (initial slope of P-I and curve) and P sub(max) (maximum specific growth rate) values. When this was done, vertical integrated primary production at 140 degree W on the equator doubled (from 83 to 166 mmol C m super(-2) day super(-1)), but the zooplankton grazing on the phytoplankton also doubled (from 75 to 150 mmol C m super(-2) day super(-1)). Zooplankton biomass doubled, but there was only a slight increase in phytoplankton biomass; no phytoplankton bloom formed in this model experiment. With potential physiological limitations of phytoplankton rates greatly reduced, the characteristic equatorial plume of unused surface layer nitrate still persisted; but the nitrate-rich plume was smaller in horizontal extent and the maximum concentration was reduced by half from observed concentrations. While the reduction in the extent of the nitrate-rich plume indicates that physiological limitation plays a significant role in the maintenance of the nutrient anomaly, its persistence demonstrates that physical processes and grazing also are involved.
AN: 4061973
234 of 313
TI: Phytodetritus at the abyssal seafloor across 10 degree of latitude in the Central Equatorial Pacific
AU: Smith,-C.R.; Hoover,-D.J.; Doan,-S.E.; Pope,-R.H.; Demaster,-D.J.; Dobbs,-F.C.; Altabet,-M.A.
AF: Dep. Oceanogr., Univ. Hawaii, 1000 Pope Rd., Honolulu, HI 96822, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1996 vol. 43, no. 4-6, pp. 1309-1338
NT: Special issue: A U.S. JGOFS Process Study in the Equatorial Pacific. Part 2.
LA: English
ER: M (Marine)
AB: Fresh phytoplankton detritus (or phytodetritus) has been reported from numerous deep seafloor sites in the temperate North Atlantic and Pacific Oceans following seasonal phytoplankton blooms. Here we report the first strong evidence for abyssal accumulations of phytodetritus in the tropics, in the central equatorial Pacific. In November-December 1992 we obtained photographs and/or sediment-core samples from 61 abyssal stations (water depths of 4280-5012 m) between 12 degree S and 9 degree N along similar to 140 degree W. Greenish flocculent material was recovered from the top of multiple-core samples from 5 degree S to 5 degree N. Microscopic examination of greenish material recovered from core tops and a burrow lumen revealed relatively intact diatoms (including Rhizosolenia sp.) and other microalgae with chloroplasts containing chlorophyll. The greenish material was 1-12.5% organic carbon by weight, i.e. 5-39 times richer than associated seafloor sediments. We conclude that fresh, organic-rich phytodetritus was present on the seafloor from 5 degree S to 5 degree N along 140 degree W in November-December 1992, with highest concentrations within 2-3 degree of the equator. Because the degradation rate of this material appears to be very high, its presence at the seafloor for several months per year could yield significant phytodetrital contributions to the annual seafloor organic-carbon budget.
AN: 4061972
235 of 313
TI: Wetland mercury research: A review with case studies
AU: Rood,-B.E.
AF: Environ. Sci. Prog., Mercer Univ., 1400 Coleman Ave., Macon, GA 31207, USA
SO: CURR.-TOPICS-WETLAND-BIOGEOCHEM. 1996 vol. 2, pp. 73-108
LA: English
ER: F (Freshwater)
AB: Interestingly, there is a paucity of information regarding the role that wetlands play in the regional and global cycles of mercury (Zillioux et al., 1993). Eugene Odum has said that "a healthy wetland is an indicator of a healthy watershed" (Oglethorpe Power Corporation, 1990). As such, there is a compelling need to: 1) evaluate the status of mercury contamination in a variety of wetland types, both impacted and unimpacted by regional anthropogenic activities, 2) examine chemical and biological transformations of mercury under the unique ambient conditions associated with wetlands, and 3) reconstruct trends of mercury accumulation in wetlands preserved in the sediment record. The goals of this literature review are to provide wetland scientists with an overview of current issues and observations regarding research of environmental mercury contamination, to identify the critical need for mercury researchers to incorporate detailed wetland studies into current research, and to overview current studies of mercury in wetlands including a case study of mercury paleoecological research in the Florida Everglades.
AN: 4060829
236 of 313
TI: Stream organic matter budgets
AU: Webster,-J.R.; Meyer,-J.L.-(eds.)
AF: Dep. Biol., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA 24061, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 3-161
LA: English
ER: F (Freshwater)
AB: This analysis of organic matter dynamics in streams has 3 objectives: 1) to explore the relationships between physical characteristics of streams and their watersheds (climate, geomorphology) and stream organic matter dynamics using data from a broad geographic area; 2) to compare stream organic matter dynamics in a diverse array of streams in order to suggest determinants of observed patterns; and 3) to reveal deficiencies in currently available data on organic matter dynamics in streams. Streams were included in this analysis not to represent the global diversity of stream types but because organic matter data were available. In the introductory chapter we describe the kinds of data included for each stream and provide brief descriptions of previously published organic matter data for streams included in the comparative analysis but not described in individual chapters. The next 16 chapters present organic matter data for streams from North America, Europe, Australia, and Antarctica. Most of the streams represented are in the temperate zone of North America. Data presented include climate and geomorphic variables and organic matter inputs, exports, and standing crops. The chapters on individual streams are followed by 7 chapters analyzing physical features of these streams and specific components of the organic matter budgets.
AN: 4060498
237 of 313
TI: Canada Stream: A glacial meltwater stream in Taylor Valley, south Victoria Land, Antarctica
AU: McKnight,-D.M.; Tate,-C.M.
AF: US Geol. Surv., Water Resour. Div., 3215 Marine St., Boulder, CO 80303, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 14-17
NT: Special section: Stream organic matter budgets.
LA: English
ER: F (Freshwater)
AB: The McMurdo Dry Valleys of south Victoria Land, Antarctica, form the largest of the desert oases found along the coast of Antarctica. Although this region is an extreme cold desert, glacial meltwater streams, which flow for 6-10 wk during the austral summer, are a prominent feature of the landscape. Canada Stream is in Taylor Valley and is one of 3 major streams draining Canada Glacier. The surrounding landscape is characterized by an absence of plant life, an underlying permafrost at a depth of 0.5 m, and prominent "patterned ground" features, which are large (3-5 m across) polygonal patterns formed through freeze/thaw cycles. In contrast to the barren landscape, many of the streams contain perennial algal mats and mosses, illustrating that the presence of liquid water allows for a photosynthetically based ecosystem even under the harshest conditions. Canada Stream is one of 10 streams that flow into Lake Fryxell and is representative of 6 of those streams that have abundant algal mats for most of their length. Canada Stream has been the site of several studies of the species composition and productivity of the algal mats. Ecological and hydrologic studies of Canada Stream and 22 other streams in Taylor Valley are currently being conducted as part of the McMurdo Long-Term Ecological Research program. Most of these streams are continuously gauged, with records beginning in 1990-1993.
AN: 4059041
238 of 313
TI: Stream organic matter budgets -- introduction
AU: Webster,-J.R.; Meyer,-J.L.
AF: Dep. Biol., Virginia Polytechnic and State Univ., Blacksburg, VA 24061, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1997 vol. 16, no. 1, pp. 5-13
NT: Special section: Stream organic matter budgets.
LA: English
ER: F (Freshwater)
AB: Cummins et al. discussed the many problems associated with constructing a stream budget and concluded that stream ecology would not benefit from the development of budgets for numerous streams with short-term data. They noted that what was needed was determination of total stream budgets at a few selected sites with long-term data and sustained research programs. Although stream researchers continued to study organic matter dynamics over the next decade, no complete organic matter budgets were published. We observed that the information needed to construct organic matter budgets probably existed for numerous streams and that it would be useful to systematically assemble and analyze the available data to assess the current status of research on organic matter dynamics in streams and to suggest fruitful directions for future research. Consequently, we organized a workshop, which was held on 23 and 24 May 1993 prior to the NABS meeting in Calgary, Alberta. We invited individuals who we thought had data on, and interest in, organic matter dynamics in streams and encouraged them to suggest additional people who could contribute to the workshop; 57 scientists participated. At the workshop, we attempted to compile and analyze organic matter budgets for 27 streams. As a result of these discussions, we requested modified data sets for each site, and, over the next 2 y, we reanalyzed those data, sent them back to the research teams for verification and feedback, and synthesized the resulting information. This paper is the product of those efforts by many individuals. In addition to the sites represented at the workshop, we have added data from several other streams based on published information.
AN: 4059040
239 of 313
TI: Eukaryotic microbiota in the surface waters and sea ice of the Southern Ocean: Aspects of physiology, ecology and biodiversity in a "two-phase" ecosystem
AU: Priddle,-J.; Leakey,-R.J.G.; Archer,-S.D.; Murphy,-E.J.
AF: British Antarctic Survey, NERC, High Cross, Madingley Rd., Cambridge CB3 0ET, UK
SO: BIODIVERS.-CONSERV. 1996 vol. 5, no. 11, pp. 1473-1504
NT: Special Issue: Antarctic Microbial Diversity.
LA: English
ER: M (Marine)
AB: The Southern Ocean provides a habitat for microplankton which is strongly influenced by physical factors. Of these, one of the most important and striking is the formation of sea ice. Organisms in the ice form a unique community with specific properties and adaptations. Material and organisms are exchanged between the water column and the ice during the annual cycle, and ice is an important factor in modifying biogeochemical processes and exchange between ocean and atmosphere. The coupled system, in which a range of organisms alternate between a fluid and a solid medium, provides an interesting exercise in community ecology, and has implications for the assessment of biodiversity in understanding large-scale change.
AN: 4057772
240 of 313
TI: Bacterial chemotaxis and its potential role in marine dimethylsulfide production and biogeochemical sulfur cycling
AU: Zimmer-Faust,-R.K.; de-Souza,-M.P.; Yoch,-D.C.
AF: Department of Biology, University of California, Box 951606, Los Angeles, CA 90095-1606, USA
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 6, pp. 1330-1334
LA: English
ER: M (Marine)
AB: Dimethylsulfide (DMS) gas constitutes 90% of biogenic sulfur emissions from oceans and is an important agent in climate regulation. DMS in seawater arises primarily via lyase degradation of dimethylsulfoniopropionate (DMSP), an osmolyte produced in high concentrations by some marine phytoplankton. After being induced to synthesize DMSP lyase, cells of a marine bacterium (Alcaligenes strain M3A) significantly reduce their rate of change in direction and tumbling frequency, and they are attracted to DMSP at levels similar to those occurring near senescing phytoplankton cells (10 super(-7)-10 super(-6) M). In contrast, genetically identical bacteria without lyase induction are not attracted to DMSP. Combined with lyase activity, bacterial chemotaxis to DMSP could increase the rate of DMS production and therefore play a critical role in biogeochemical sulfur cycling between dissolved organic matter in seawater and the atmosphere.
AN: 4057139
241 of 313
TI: Bromoperoxidase and iodoperoxidase enzymes and production of halogenated methanes in marine diatom cultures
AU: Moore,-R.M.; Webb,-M.; Tokarczyk,-R.; Wever,-R.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, NS, Canada
SO: J.-GEOPHYS.-RES.-C-OCEANS 1996 vol. 101, no. C9, pp. 20,899-20,908
LA: English
ER: M (Marine)
AB: Halogenated methanes produced in the oceans are important as carriers of chlorine, bromine, and iodine into the atmosphere. There they play roles in the regulation of ozone in the stratosphere and perhaps in the Arctic troposphere at polar sunrise. While the mechanisms for the production of some polyhalogenated compounds by marine macrophytes have previously been substantially elucidated, the same has not been true in the case of marine phytoplankton. We describe laboratory experiments on the production of various brominated and iodinated compounds in cultures of marine diatoms, obtained from the Provasoli-Guillard Center for Culture of Marine Phytoplankton collections (Bigelow Laboratory for Ocean Sciences, Maine, USA; CCMP). Species examined included Nitzschia sp. (CCMP 580), Nitzschia arctica, Porosira glacialis, and two Navicula sp. (CCMP 545 and 546).
AN: 4056424
242 of 313
TI: The fate of marine autotrophic production
AU: Duarte,-C.M.; Cebrian,-J.
AF: Centro de Estudios Avanzados de Blanes, CSIC, Cami de Santa Barbara s/n, 17300 Blanes, Girona, Spain
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 8, pp. 1758-1766
LA: English
ER: M (Marine)
AB: The fate of photosynthetic carbon in marine ecosystems dominated by different types of primary producers was examined by compiling published reports on herbivory, autotrophic respiration, decomposition, carbon storage, and export rates as fractions of net primary production (NPP) in ecosystems dominated by different types of autotrophs (i.e. oceanic and coastal phytoplankton, microphytobenthos, coral reef algae, macroalgae, seagrasses, marsh plants, and mangroves). A large fraction (>40%) of the NPP of marine ecosystems is decomposed within the system, except for microphytobenthos (decomposition, similar to 25% of NPP). Herbivory tends to be highest for microalgae (planktonic and benthic, >40% of NPP) and macroalgae (33.6 plus or minus 4.9% of NPP) and is somewhat less for higher plants. Microphytobenthos export on average a much higher proportion of their NPP than do other microalgal communities, whereas marine macrophytes, except marsh plants, export a substantial proportion (24.3-43.5% on average) of their NPP. The fraction of NPP stored in sediments is 4-fold greater for higher plants ( similar to 10-17% of NPP) than for algae (0.4-6% of NPP). On average, similar to 90% of the phytoplankton NPP is used to support local heterotrophic metabolism (i.e. grazed or decomposed). This fraction is even higher in oceanic communities. Mangrove forests, and to a lesser extent seagrass meadows and macroalgal beds, produce organic carbon well in excess of the ecosystem requirements, with excess photosynthetic carbon (i.e. export rate plus storage) in these ecosystems representing similar to 40% of NPP. Extrapolation of these results to the global ocean identifies marine angiosperms, which only contribute 4% of total ocean NPP, as major contributors of the NPP stored (30% of total ocean carbon storage) and subsequently buried in marine sediments. Consideration of burial of NPP from marine angiosperms should lead to estimates of total burial of marine NPP that exceed current estimates by 15-50%.
AN: 4055952
243 of 313
TI: Dynamic response of deep-sea sediments to seasonal variations: A model
AU: Soetaert,-K.; Herman,-P.M.J.; Middelburg,-J.J.
AF: Netherlands Inst. Ecol., Vierstraat 28, 4401 EA Yerseke, The Netherlands
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 8, pp. 1651-1668
LA: English
ER: M (Marine)
AB: We present a dynamic, numerical model of early diagenetic processes that can be used to examine the response of different organic carbon mineralization pathways, concentration vs. depth profiles, and the resultant fluxes to seasonally varying carbon deposition. We show that there can be substantial temporal variability in sediment-water fluxes as well as in the relative contribution of different organic carbon mineralization pathways and oxygen consumption processes in deep-sea sediments. The timing and amplitude of the sediment response are most sensitive to the reactivity of the organic matter. We show that the fluxes of dissolved substances can be approximated by assuming that these constituents are at steady state with the carbon profiles. The model is used to reconcile a time series of community oxygen consumption rates, dissolved oxygen, nitrate, ammonia, and manganese profiles, and solid-phase organic carbon profiles at a deep-sea station in the Pacific. The organic carbon that is deposited is very reactive (7.2 yr super(-1)), which causes a fast response of the sediment community to seasonal pulses in carbon flux and significant temporal variation in oxygen and nutrient fluxes. The model predicts large seasonal variations in the relative importance of oxic (48-71%), denitrification (12-17%), and anoxic (16-37%) pathways. There is also substantial variation in the pore-water profiles of oxygen, nitrate, ammonia, and other reduced substances over the seasonal cycle, indicating that seasonal variability should be taken into account when extrapolating from a single observation to yearly averaged values.
AN: 4055948
244 of 313
TI: Nitrification in the euphotic zone as a source for nitrite, nitrate, and nitrous oxide at Station ALOHA
AU: Dore,-J.E.; Karl,-D.M.
AF: Dep. Oceanogr., Sch. Ocean and Earth Sci. and Technol., Univ. Hawaii, Honolulu, HI 96822, USA
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 8, pp. 1619-1628
LA: English
ER: M (Marine)
AB: We measured chemoautotrophic bacterial nitrification rates in the lower euphotic zone at the North Pacific Time-series Station ALOHA using low-level chemical assays and inhibitor-sensitive radiocarbon uptake experiments. These measurements were compared with independent nitrification rate estimates based on nitrous oxide distributions, nitrate assimilation rates based on nitrate changes during an in situ incubation, and historical estimates of nitrification and nitrate assimilation from this region. Ammonium oxidation rates ranged from 1.0 to 137.4 mu mol m super(-3) d super(-1), and nitrite oxidation rates varied from undetectable to 138.0 mu mol m super(-3) d super(-1). Conservative estimates of depth-integrated euphotic zone nitrification rates from the complete three-cruise data set were 0.69 mmol m super(-2) d super(-1) for nitrite oxidation and 1.64 mmol m super(-2) d super(-1) for ammonium oxidation. The highest nitrification rates were found below the primary nitrite maximum, suggesting a significant contribution of euphotic zone ammonium oxidation to the nitrite pool below but not within this feature. A mass balance of nitrous oxide indicates that this gas is produced within the euphotic zone at a rate of 1.68-7.94 mu mol m super(-2) d super(-1). The nitrous oxide production rate provides an independent estimate of the total euphotic zone nitrification rate in the range of 0.34-1.59 mmol m super(-2) d super(-1). We estimate that the total euphotic zone nitrification rate is 47-142% of the concurrent nitrate assimilation rate, indicating that nitrification in the euphotic zone is an important source of regenerated nitrate.
AN: 4055934
245 of 313
TI: Wastewater discharge, seagrass decline and algal proliferation on the Cote d'Azur
AU: Chisholm,-J.R.M.; Fernex,-F.E.; Mathieu,-D.; Jaubert,-J.M.
AF: Australian Inst. Mar. Sci., PMB No. 3, Townsville MC, Queensland, Australia
SO: MAR.-POLLUT.-BULL. 1997 vol. 34, no. 2, pp. 78-84
LA: English
ER: M (Marine)
AB: The green alga, Caulerpa taxifolia, has recently proliferated in areas of the N-W Mediterranean that were previously dominated by the seagrass Posidonia oceanica. Sediments in areas of proliferation had high exoenzyme activities, NH sub(4) super(+) concentrations and production rates, but very low capacities to transform organic-N into NH sub(4) super(+) relative to the quantity of organic material available. All sediments supporting C. taxifolia contained large quantities of precipitated phosphorus and exhibited extremely low capacities to transform NH sub(4) super(+) into NO sub(2) super(-) and NO sub(3) super(-). Low transformative capacities and high phosphate concentrations are characteristic of sediments that have been polluted by urban wastewater. Where C. taxifolia did not exist, or where growth had stabilized, sediments had exoenzyme activities, NH sub(4) super(+) concentrations and NH sub(4) super(+) production rates that were proportional to organic-N transformative potential. All sediments contained significant concentrations of non-crystalline sulphide. Caulerpa taxifolia proliferation may be linked to enrichment of substrata by urban wastewater and dead or dying seagrass vegetation.
AN: 4055364
246 of 313
TI: Trace metals in mesozooplankton of the North Sea: Concentrations in different taxa and preliminary results on bioaccumulation in copepod collectives (Calanus finmarchicus/C. helgolandicus)
AU: Zauke,-G.-P.; Krause,-M.; Weber,-A.
AF: FB Biologie (ICBM), Carl von Ossietzky Universitaet, Postfach 2503, D-26111 Oldenburg, FRG
SO: INT.-REV.-GESAMT.-HYDROBIOL. 1996 vol. 81, no. 1, pp. 141-160
NT: Incl. bibliogr.: 56 refs.
LA: English
ER: M (Marine)
AB: Trace metals (Cd, Cu, Zn, Ph, Ni) were determined in different zooplankton taxa to assess their role in the biogeochemical cycle in the North Sea. Results of semi-static bioaccumulation experiments on board ship using collectives of Calanus finmarchicus/C. helgolandicus were in agreement with a net accumulation strategy, thus meeting an inevitable precondition for their utilization as biomonitors. Cd, Cu and Zn concentrations in field samples of zooplankton displayed a pronounced variability between taxa, with Cd ranging from 0.13 mg/kg (d.w.) in fish larvae to 51 mg/kg in hyperiid amphipods. Almost no information is available ahout metal requirements of copepods. However, most of our and worldwide reported Cu concentrations in calanoid copepods (6-22 mg/kg of enzymatic requirements of decapod crustaceans. Cd levels in Calanus collectives increased significantly from 0.68 mg/kg in the German Bight to 11 mg/kg at some station around Scotland ahove 59 degree N, in line with literature data reported for benthic decapod crustaceans.
AN: 4053713
247 of 313
TI: North Pacific Ocean CO sub(2) disequilibrium for spring through summer, 1985-1989
AU: Landrum,-L.L.; Gammon,-R.H.
AF: Sch. Oceanography, Univ. Washington, Seattle, WA, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1996 vol. 101, no. C12, pp. 28539-28555
LA: English
ER: M (Marine)
AB: Extensive measurements of CO sub(2) fugacity in the North Pacific surface ocean and overlying atmosphere during the years 1985-1989 are synthesized and interpreted to yield a basin-wide estimate of Delta fCO sub(2). The observations, taken from February through early September, suggest that the subtropical and subarctic North Pacific is a small sink for atmospheric CO sub(2) (0.07 to 0.2 Gton C (half year) for the region north of 15 degree N). Objective analysis techniques are used to estimate uncertainty fields resulting from constructing basin-wide contours of oceanic fCO sub(2) on the basis of individual cruise transects. The uncertainties are significant and imply that future sampling programs need to recognize that estimating oceanic uptake of anthropogenic CO sub(2) from ship-transect observations of oceanic fCO sub(2) alone will require very extensive sampling.
AN: 4052810
248 of 313
TI: Biogeochemical tracers of the marine cyanobacterium Trichodesmium
AU: Carpenter,-E.J.; Harvey,-H.R.; Fry,-B.; Capone,-D.G.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, New York, NY 11794-5000, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1997 vol. 44, no. 1, pp. 27-38
LA: English
ER: M (Marine)
AB: We examined the utility of several biogeochemical tracers for following the fate of the planktonic diazotrophic cyanobacterium Trichodesmium in the sea. The presence of a (C sub(10)) fatty acid previously reported was observed in a culture of Trichodesmium but was not found in natural samples. This cyanobacterium had high concentrations of C sub(14) and C sub(16) acids, with lesser amounts of several saturated and unsaturated C sub(18) fatty acids. This composition was similar to that of other marine cyanobacteria. The major hydrocarbon identified was the C sub(17) n-alkane, which was present in all samples from the five stations examined. Sterols common to algae and copepods were observed in many samples along with hopanoids representative of bacteria, suggesting a varied community structure in colonies collected from different stations. We found no unique taxonomic marker of Trichodesmium among the sterols. Measurements of the delta super(15)N and delta super(13)C in Trichodesmium samples from the SW Sargasso and NW Caribbean Seas averaged -0.4ppt (range from -0.7 to -0.25ppt) and -12.9ppt (range from -15.2 to -11.9ppt), respectively, thus confirming previous observations that this cyanobacterial diazotroph has both the lowest delta super(15)N and highest delta super(13)C of any marine phytoplankter observed to date. A culture of Trichodesmium grown under diazotrophic conditions had a delta super(15)N between -1.3 and -3.6ppt. Our results support the supposition that the relatively low delta super(15)N and high delta super(13)C values observed in suspended and sediment-trapped material from some tropical and subtropical seas result from substantial input of C and N by Trichodesmium.
AN: 4051874
249 of 313
TI: Relationship between Minjiang River Estuary trace metals and nutrients
AU: Zou,-Dong-liang; Gao,-Shu-ying
AF: Dep. Oceanogr., Inst. Subtropical Oceanology, Xiamen Univ., Xiamen 361005, People's Rep. China
SO: CHIN.-J.-OCEANOL.-LIMNOL. 1996 vol. 14, no. 3, pp. 261-265
LA: English
ER: B (Brackish)
AB: This study on the relationships between dissolved Cd, Cu, Pb and nutrients in the Minjiang River Estuary during high and low discharges (in June and Oct., 1990) showed that during both high and low discharges Cd, Cu and Pb exhibited additive, conservative and removal behaviour, respectively. Cd increase appeared to be primarily related to Cd regeneration from microplankton and its organic remains, while Pb removal was dominated by abiotic processes.
AN: 4051197
250 of 313
TI: A vertical distribution model of nutrients and dissolved oxygen in the southern Taiwan Strait
AU: Shang,-Shao-ling; Hong,-Hua-sheng
AF: Environ. Sci. Res. Cent., Xiamen Univ., Xiamen 361005, People's Rep. China
SO: CHIN.-J.-OCEANOL.-LIMNOL. 1995 vol. 13, no. 1, pp. 51-61
LA: English
ER: M (Marine)
AB: Since vertical transport of nutrients and dissolved oxygen are quite important in the water column and have drawn serious attention these recent years, a one-dimension numerical model is tried to simulate the vertical distribution of nutrients and dissolved oxygen in June at two research sites in the southern Taiwan Strait. Physical transport parameters are calibrated by temperature simulation, and then are used to simulate the profiles of NO sub(3), PO sub(4) and dissolved oxygen. The simulation was generally successful for both stations. The importance of various factors, such as upwelling, tidal current and biogeochemical activities, which influence the vertical distribution of nutrients and dissolved oxygen, is revealed by analysis of the modeling results. Some important rates, fluxes and ratios are also estimated and discussed on the basis of simulation.
AN: 4051193
251 of 313
TI: Trichodesmium, a globally significant marine cyanobacterium
AU: Capone,-D.G.; Zehr,-J.P.; Paerl,-H.W.; Bergman,-B.; Carpenter,-E.J.
AF: Chesapeake Biol. Lab., Cent. Environ. and Estuarine Stud., Univ. Maryland, Solomons, MD 20688, USA
SO: SCIENCE-WASH. 1997 vol. 276, no. 5316, pp. 1221-1229
LA: English
ER: M (Marine)
AB: Planktonic marine cyanobacteria of the genus Trichodesmium occur throughout the oligotropic tropical and subtropical oceans. Their unusual adaptations, from the molecular to the macroscopic level, contribute to their ecological success and biogeochemical importance. Trichodesmium fixes nitrogen gas (N sub(2)) under fully aerobic conditions while photosynthetically evolving oxygen. Its temporal pattern of N sub(2) fixation results from an endogenous daily cycle that confines N sub(2) fixation to daylight hours. Trichodesmium colonies provide a unique pelagic habitat that supports a complex assemblage of consortial organisms. These colonies often represent a large fraction of the plant biomass in tropical, oligotropic waters and contribute substantially to primary production. N sub(2) fixation by Trichodesmium is likely a major input to the marine and global nitrogen cycle.
AN: 4049443
252 of 313
TI: super(15)N evidence for the origin and cycling of inorganic nitrogen in a small Amazonian catchment
AU: Brandes,-J.A.; McClain,-M.E.; Pimentel,-T.P.
AF: Univ. Washington, Sch. Oceanogr., Box 357940, Seattle, WA 98195-7940, USA
SO: BIOGEOCHEMISTRY 1996 vol. 34, no. 1, pp. 45-56
LA: English
ER: F (Freshwater)
AB: The delta super(15)N composition of the dominant form of dissolved inorganic nitrogen (DIN) was determined in upland groundwater, riparian groundwater, and stream water of the Barro Branco catchment, Amazonas, Brazil. The delta super(15)N composition of organic nitrogen in riparian and upland leaf litter was also determined. The data for these waters could be divided into three groups: upland groundwater DIN predominately composed of NO sub(3) super(-) with delta super(15)N values averaging 6.25 plus or minus 0.9ppt; riparian groundwater DIN primarily composed of NH sub(4) super(+) with delta super(15)N values averaging 9.17 plus or minus 1.0ppt, and stream water DIN predominately composed of NO sub(3) super(-) with delta super(15)N values averaging 4.52 plus or minus 0.8ppt. Nitrate samples taken from the stream source and from the stream adjacent to the groundwater transects showed a downstream increase in delta super(15)N from 1.0ppt to 4.5ppt. Leaf litter samples averaged 3.5 plus or minus 1.2ppt. The observed patterns in isotopic composition, together with previously observed inorganic nitrogen species and concentration shifts between upland, riparian and stream waters, suggest that groundwater DIN is not the primary source of DIN to the stream. Instead, the isotopic data suggest that remineralization of organic nitrogen within the stream itself may be a major source of stream DIN, and that the majority of DIN entering the stream via groundwater flowpaths is removed at the riparian-stream interface.
AN: 4048129
253 of 313
TI: Nitrate reduction in sediments of lowland tropical streams draining swamp forest in Costa Rica: An ecosystem perspective
AU: Duff,-J.H.; Pringle,-C.M.; Triska,-F.J.
AF: U.S. Geol. Surv., Water Resour. Div., Mail Stop 496, 345 Middlefield Rd., Menlo Park, CA 94025-3591, USA
SO: BIOGEOCHEMISTRY 1996 vol. 33, no. 3, pp. 179-196
LA: English
ER: F (Freshwater)
AB: Nitrate reduction and denitrification were measured in swamp forest streams draining lowland rain forest on Costa Rica's Atlantic slope foothills using the C sub(2)H sub(2)-block assay and sediment-water nutrient fluxes. Denitrification assays using the C sub(2)H sub(2)-block technique indicated that the full suite of denitrifying enzymes were present in the sediment but that only a small fraction of the functional activity could be expressed without adding NO sub(3) super(-). Under optimal conditions, denitrification enzyme activity averaged 15 nmoles cm super(-3) sediment h super(-1). Areal NO sub(3) super(-) reduction rates measured from NO sub(3) super(-) loss in the overlying water of sediment-water flux chambers ranged from 65 to 470 umoles m super(-2) h super(-1). Oxygen loss rates accompanying NO sub(3) super(-) depletion averaged 750 umoles m super(-2) h super(-1). Corrected for denitrification of NO sub(3) super(-) oxidized from NH sub(4) super(+) in the sediment, gross NO sub(3) super(-) reduction rates increase by 130 umoles m super(-2) h super(-1), indicating nitrification may be the predominant source of NO sub(3) super(-) for NO sub(3) super(-) reduction in swamp forest stream sediments. Under field conditions approximately 80% of the increase in inorganic N mass along a 1250-m reach of the Salto River was in the form of NO sub(3) super(-) with the balance NH sub(4) super(+). Scrutiny of potential inorganic N sources suggested that mineralized N released from the streambed was a major source of the inorganic N increase. Despite significant NO sub(3) super(-) reduction potential, swamp forest stream sediments appear to be a source of inorganic N to downstream communities.
AN: 4048128
254 of 313
TI: Chemical fluxes on the sediment-water interface: Direct measurements
AU: Rozanov,-A.G.
AF: P.P. Shirshov Inst. Oceanol., Russian Acad. Sci., Russia
CO: 30. Int. Geological Congress, Beijing (China), 4-14 Aug 1996
SO: ABSTRACTS-OF-PAPERS-PRESENTED-AT-THE-30TH-INTERNATIONAL-GEOLOGICAL-CONGRESS. 1996 vol. 1, p. 28
NT: Volume 1 of 3.
LA: English
ER: M (Marine)
AB: Concentrations of many dissolved chemical components are drastically changed in vicinity of the surface and in the top layers of marine sediments as a result of postsedimentation processes mediated chemically and biochemically. Chemical diffusion as well as physical (waves, tides, currents, fluxes) and biological treatment (bioturbation, bioirrigation) are responsible for chemical fluxes being generated between the bottom water and the sediment. Studies of the pore water composition do not give full estimates of the chemical exchange on the water-sediment interface but are very fruitful when combined with direct flux measurements i.g. with benthic chamber method. In this case both diagenetic processes within the upper sediment and processes on the sediment surface are taken into account. In benthic chamber experiments carried out on the shelf area of the Black, Azov and Baltic Seas the methods of measurements and result processing gave not only the values of fluxes of dissolved components but also such parameters as thickness of the diffusion sublayer, depth of penetration into the sediment (for oxygen), orders of the reactions etc. Experimental method was offered to correct the data obtained in closed system (benthic chambers) for the open water-sediment system. The values of oxygen consumption by the sediment vary from 1 to 200 mM m super(-2) day super(-1), the fluxes of nutrients from the sediment amounts to 1 for HPO sub(4) super(2-), 20 for SiO sub(4) super(4-), 40 for NH sub(4) super(+), 400 mM m super(-2) day super(-1) for HCO sub(3) super(-). In some cases directions of the fluxes can be opposite (HPO sub(4) super(2-), NH sub(4) super(+)). Chemical exchange on the water-sediment interface in a global scale is still not very certain, but this is evidently important for regional biogeochemical cycles i.g. in marginal parts of the ocean. (DBO)
AN: 4048083
255 of 313
TI: Evolution of the nitrogen cycle and its influence on the biological sequestration of CO sub(2) in the ocean
AU: Falkowski,-P.G.
AF: Oceanogr. and Atmos. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: NATURE 1997 vol. 387, no. 6630, pp. 272-275
LA: English
ER: M (Marine)
AB: Over geological time, photosynthetic carbon fixation in the oceans has exceeded respiratory oxidation of organic carbon. The imbalance between the two processes has resulted in the simultaneous accumulation of oxygen in, and drawdown of carbon dioxide from, the Earth's atmosphere, and the burial of organic carbon in marine sediments. It is generally assumed that these processes are limited by the availability of phosphorus, which is supplied by continental weathering and fluvial discharge. Over the past two million years, decreases in atmospheric carbon dioxide concentrations during glacial periods correlate with increases in the export of organic carbon from surface waters to the marine sediments, but variations in phosphorus fluxes appear to have been too small to account for these changes. Consequently, it has been assumed that total oceanic primary productivity remained relatively constant during glacial-to-interglacial transitions, although the fraction of this productivity exported to the sediments somehow increased during glacial periods. Here I present an analysis of the evolution of biogeochemical cycles which suggests that fixed nitrogen, not phosphorus, limits primary productivity on geological timescales. Small variations in the ratio of nitrogen fixation to denitrification can significantly change atmospheric carbon dioxide concentrations on glacial-to-interglacial timescales. The ratio of these two processes appears to be determined by the oxidation state of the ocean and the supply of trace elements, especially iron.
AN: 4043833
256 of 313
TI: The short-term fate of fresh algal carbon in continental slope sediments
AU: Blair,-N.E.; Levin,-L.A.; DeMaster,-D.J.; Plaia,-G.
AF: Dep. Mar., Earth and Atmos. Sci., North Carolina State Univ., Raleigh, NC 27695-8208, USA
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 6, pp. 1208-1219
LA: English
ER: M (Marine)
AB: Emplacement of a tracer mixture containing super(13)C-labeled green algae on the sea floor of the continental slope offshore of Cape Hatteras, North Carolina, elicited a rapid response over 1.5 d from the dense benthic community. Certain deposit-feeding annelids (e.g. Scalibregma inflatum and Aricidea quadrilobata) became heavily labeled with super(13)C as a result of ingestion of the algae. super(13)C-labeled organic matter was transported to a depth of at least 4-5 cm into the seabed during the 1.5-d period, presumably as a consequence of a feeding-associated activity. Nonlocal transport produced subsurface peaks in organic super(13)C at 2-3 cm. Dissolved inorganic super(13)C, produced by the oxidation of the labeled algae, penetrated to 10-cm depth. The transport of highly reactive organic matter from the sediment surface at initial velocities greater than or equal to 3 cm d super(-1) is expected to be an important control of subsurface benthic processes in slope environments characterized by abundant macro-faunal populations. Anaerobic processes, which are enhanced on the Cape Hatteras slope relative to adjacent areas, may be promoted by the rapid injection of reactive material into subsurface sediments. The transport, in turn, is a consequence of the dense infaunal populations that are supported by the rapid deposition of organic carbon in this region.
AN: 4041152
257 of 313
TI: Nitrogen speciation and nitrification potential in the Skagerrak area during the SKAGEX IV experiment
AU: Enoksson,-V.; Fogelqvist,-E.; Fonselius,-S.
AF: Dep. Gen. and Mar. Microbiol., Goeteborg Univ., Medicinaregatan 9C, S-413 90 Goeteborg, Sweden
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1996 vol. 43, no. 7, pp. 1029-1044
LA: English
ER: M (Marine)
AB: Nitrification is the oxidation of ammonium to nitrite by Nitrosomonas-like bacteria and the further oxidation of the nitrite to nitrate by Nitrobacter-like bacteria. Nitrification was studied in relation to the inorganic nitrogen species in the Skagerrak in May 1991 during the SKAGEX IV expedition. The distribution of density, ammonium, nitrite and nitrate are shown for the four north-south sections and, for two of these, the distribution of nitrification potential (NP, i.e. nitrification with excess ammonium during incubation) and oxygen saturation values are also presented. Highly saline and ammonium rich Atlantic/North Sea water was sinking into the Skagerrak along the Danish slope, where it gradually mixed with the "old" and relatively stagnant Skagerrak water with high nitrate concentrations but very low ammonium concentrations. The zone of mixing was characterised by high concentrations of nitrite, an intermediate product during the bacterial oxidation of ammonium to nitrate. The NP rates were in the range 0-60 nmol/l/day. Water masses with undetectable or low NP included the upper water layers and water flowing in at depth. Maximum NP rates were found in or near the zone with high nitrite concentrations just below the upper layers and at the border between inflowing water and "old" Skagerrak water at depth. It is postulated that nitrification was stimulated in the mixture of inflowing, ammonium rich water and "old" Skagerrak water.
AN: 4041018
258 of 313
TI: Mercury content in ecosystem components of the Alekseev Inlet (Peter the Great Bay, Sea of Japan).
OT: Soderzhanie rtuti v komponentakh ehkosistemy bukhty Alekseeva (zaliv Petra Velikogo Yaponskogo morya)
AU: Luchsheva,-L.N.
AF: TINRO, Vladivostok, Russia
SO: BIOL.-MORYA-MAR.-BIOL. 1995 vol. 21, no. 6, pp. 412-415
LA: Russian
ER: M (Marine)
AB: Elevated mercury concentrations were recorded in the water, bottom sediments and the soft tissues of 3 bivalve species from the Alekseev Inlet. Maximum Hg concentrations in water (0.237 mu g/l) and sediments (0.529 mu g/l) exceeded those in the control area (Peter the Great Bay) by over 10 and 5 times, respectively. The anomalous zone at the northeastern coast of the inlet is formed by Hg entering the near-bottom water layer from an endogenous submarine spring and being distributed over the inlet by currents. In molluscs from the anomalous zone, Hg content exceeding maximum permissible concentration (MPC 0.2 mu g/g wet weight) was recorded in the mantle (0.540 mu g/g), digestive gland (0.450 mu g/g) and gonad (0.390 mu g/g) of the horse mussel Modiolus kurilensis, and in the digestive gland (0.560 mu g/g) of the giant mussel Crenomytilus grayanus. Hg concentrations close to MPC were recorded in the digestive gland and adductor muscle of the scallop Mizuhopecten yessoensis.
AN: 4040737
259 of 313
TI: Temporal and spatial stability of bacterioplankton biomass and productivity in an atoll lagoon
AU: Torreton,-J.-P.; Dufour,-P.
AF: Cent. ORSTOM de Tahiti, BP 529, Papeete, French Polynesia
SO: AQUAT.-MICROB.-ECOL. 1996 vol. 11, no. 3, pp. 251-261
LA: English
ER: M (Marine)
AB: Spatial and temporal variations of bacterioplankton biomass, production and growth rates were investigated 6 times from 1991 to 1994 in Tikehau lagoon (Tuamotu, French Polynesia). The water column was homogeneous from the surface to the bottom (20 m) at the reference station but some horizontal variations were detected, with biomass and production increasing from the reef-flat spillways (oceanic water inflow) to the main part of the lagoon and decreasing from the relatively eutrophic shore (near the village) to the main part of the lagoon. However, both of these perturbations were limited to the immediate vicinity of these areas. Diel fluctuations of bacterial biomass and growth rate were slight (coefficient of variation, CV < 20 %) and showed no significant pattern. Day-to-day variations recorded over periods of up to 20 consecutive days appeared also to be limited (CV < 25 %). A significant correlation between wind and total abundance of bacteria in the water column suggested that these day-to-day variations may be in part explained by wind, probably inducing resuspension of sediments. No significant pattern appeared from comparison of the 6 cruises spread over different seasons. Cruise averages differed slightly from each other, with CV for all cruises averaging 34, 10 and 41 % for bacterioplankton biomass, production and growth rate, respectively. Tikehau lagoon appears to be a very stable ecosystem for bacterioplankton processes and therefore differs strongly from other reef water column systems. This untypical stability might be explained by the long residence time of water (170 d), the strong stability of the oceanic surrounding water (South Pacific Gyre), the weak seasonality of primary producers and the limited inputs from corals, bordering islands and sediments.
AN: 4039083
260 of 313
TI: Inhibition of bacterial activities by solar radiation in nearshore waters and the Gulf of Mexico
AU: Aas,-P.; Maille-Lyons,-M.; Pledger,-R.; Mitchell,-D.L.; Jeffrey,-W.H.
AF: Univ. West Florida, Cent. for Environ. Diagnostics and Bioremediation, 11000 Univ. Pkwy., Pensacola, FL 32514, USA
SO: AQUAT.-MICROB.-ECOL. 1996 vol. 11, no. 3, pp. 229-238
LA: English
ER: M (Marine)
AB: The effects of ultraviolet (UV) radiation on thymidine and leucine incorporation were examined in surface waters from the Gulf of Mexico and Santa Rosa Sound, a mesotrophic estuary in northwest Florida, USA. Whole and 0.8 mu m filtered surface waters were incubated with super(3)H-thymidine and super(14)C-leucine in UV transparent containers under natural solar radiation. Solar radiation was either not filtered (samples exposed to UV-B, UV-A, and photosynthetically active radiation, PAR), filtered through Mylar 500D (samples exposed to UV-A and PAR), or filtered through Acrylite OP3 (samples exposed only to PAR). In Santa Rosa Sound, thymidine incorporation was inhibited an average of 44% relative to dark controls when exposed to unfiltered solar radiation. PAR contributed 23% to the total thymidine inhibition, while UV-A and UV-B contributed 37% and 39%, respectively, to total inhibition. Leucine incorporation in Santa Rosa Sound was inhibited 29% by full solar radiation. The majority of the total leucine inhibition was due to UV-B (83%), while PAR only treatments showed leucine incorporation rates 10% higher than dark controls. For the Gulf of Mexico experiments, full solar radiation inhibited thymidine incorporation approximately twice as much as leucine incorporation. However, there were no consistent patterns in differences due to different wavelengths. Both thymidine and leucine incorporation were inhibited to a greater extent in <0.8 mu m filtered water samples than in whole water samples, suggesting that the presence of primary producers may mediate the detrimental effects of solar radiation on bacterioplankton. Surface water was also incubated in situ with thymidine at fixed depths in UV transparent and darkened containers at 3 locations in the Gulf of Mexico. Total inhibition was 60 to 70% at the surface and was evident to 15 m. Comparison with radiometric data and DNA dosimeters indicated that UV-B exerted the greatest effect in the upper 5 m while below that the inhibition was most likely due to longer wavelengths. Our results suggest that both UV and visible solar radiation can negatively affect bacterial metabolism and failure to take into account the effects of light may result in the overestimation of bacterioplankton production in surface waters.
AN: 4038237
261 of 313
TI: Mineralization in a northeastern Greenland sediment: Mathematical modelling, measured sediment pore water profiles and actual activities
AU: Rysgaard,-S.; Berg,-P.
AF: Natl. Environ. Res. Inst., Vejlsovej 25, DK-8600 Silkeborg, Denmark
SO: AQUAT.-MICROB.-ECOL. 1996 vol. 11, no. 3, pp. 297-305
LA: English
ER: M (Marine)
AB: A mathematical computer model describing mineralization processes and transport of solutes within sediments was developed based on the degradation of organic matter, stoichiometrically coupled to the consumption of O sub(2) in the oxic layers, and to NO sub(3) super(-) and SO sub(4) super(2-) in the anoxic layers. The reaction rates obey Michaelis-Menten type kinetics and all transport of solutes is assumed to take place by diffusion. The model was tested on a northeastern Greenland sediment and gave accurate simulations of the measured concentration profiles. In addition, measured processes of nitrification, coupled nitrification-denitrification, denitrification of water column NO sub(3) super(-), NH sub(4) super(+) mineralization and the fluxes of NH sub(4) super(+) and NO sub(3) super(-) across the sediment-water interface were predicted with great accuracy. Since the model is based on Michaelis-Menten type kinetics and diffusional transport mechanisms, it is of general use and provides an important tool to evaluate the regulation of biogeochemical cycling in sediments. This is shown in a series of simulations predicting the effect of various concentrations in the water column of O sub(2) and NO sub(3) super(-) on the rates of nitrification and denitrification. The results are in good agreement with previously published measurements.
AN: 4038234
262 of 313
TI: Abundant populations of iron and manganese sequestering bacteria in coastal water
AU: Heldal,-M.; Fagerbakke,-K.M.; Tuomi,-P.; Bratbak,-G.
AF: Dep. Microbiol., Univ. Bergen, Jahnebk. 5, N-5020 Bergen, Norway
SO: AQUAT.-MICROB.-ECOL. 1996 vol. 11, no. 2, pp. 127-133
LA: English
ER: M (Marine)
AB: It has recently been suggested that iron is a limiting factor for phytoplankton production in nutrient-rich seas. Here we report on a group of bacteria in coastal marine surface waters forming extensive appendages with apparently high affinity for iron and manganese (Fe-Mn bacteria). Bacteria and particles were harvested by centrifugation onto grids for Transmission Electron Microscope (TEM) X-ray microanalysis. Four different morphotypes of Fe-Mn bacteria were identified. The total numbers of these bacteria were at the highest in the range of 5.5 x 10 super(3) to 1.5 x 10 super(4)/ml. The amount of iron bound was 10 to 110 fg/cell including appendages, and the Mn:Fe ratio (w/w) of the metal-encrusted appendages varied between 0.37 and 5.7. In some environments the Fe content of these bacteria was equivalent to a bulk concentration of about 10 nM. The Fe and Mn content per unit biomass of these bacteria is 1000 to 10000 times that of most other microorganisms. These organisms may thus be important for both cycling and sedimentation of Fe and Mn in marine ecosystems and for marine productivity.
AN: 4038207
263 of 313
TI: Effects of Tubifex tubifex (Oligochaeta: Tubificidae) on N-mineralization in freshwater sediments, measured with super(15)N isotopes
AU: Pelegri,-S.P.; Blackburn,-T.H.
AF: Dep. Biol., Univ. Southwestern Louisiana, PO Box 42451, Lafayette, LA 70504-2451, USA
SO: AQUAT.-MICROB.-ECOL. 1995 vol. 9, no. 3, pp. 289-294
LA: English
ER: F (Freshwater)
AB: Sediment cores containing different densities of Tubifex tubifex, ranging from 0 to 70000 ind/m super(2), were incubated in the laboratory. Rates of O sub(2) and NO sub(3) super(-) uptake, NH sub(4) super(+) production, nitrification and denitrification were determined from sediment-water fluxes. Pore water NH sub(4) super(+) was measured at the end of the experiment. At natural densities, similar to 50000 ind. m super(-2), there were increased rates of O sub(2) consumption (x2), denitrification of water phase NO sub(3) super(-) (x3) and NH sub(4) super(+) efflux (x26). Nitrification was stimulated at low worm densities, but inhibited at higher worm densities. The transport of reduced compounds and organic matter, with the fecal pellets, to the sediment surface stimulated anoxic conditions in the inhabited microcosms. These anoxic conditions led to increased rates of denitrification and were responsible for the decrease in nitrification at higher worm densities. Approximately 25% of the NO sub(3) super(-) produced by nitrification within the sediment was subsequently denitrified. Denitrification was responsible for 25% of the NO sub(3) super(-) disappearance from the system. The higher rates of denitrification were counterbalanced by higher rates of NH sub(4) super(+) flux from the sediment. It is likely, however, that the presence of T. tubifex resulted in a net loss of nitrogen that could otherwise have been used by the primary producers.
AN: 4038080
264 of 313
TI: Impact of the soft-shell clam Mya arenaria on sulfate reduction in an intertidal sediment
AU: Hansen,-K.; King,-G.M.; Kristensen,-E.
AF: Inst. Biol., Odense Univ., Campusvej 55, DK-5230 Odense M, Denmark
SO: AQUAT.-MICROB.-ECOL. 1996 vol. 10, no. 2, pp. 181-194
LA: English
ER: M (Marine)
AB: Sulfate reduction and various parameters related to the sulfur cycle were examined at mm to cm scales around burrows of the soft-shell clam Mya arenaria in an intertidal sediment (Lowes Cove, Maine, USA). Sulfate reduction rates were 1.5 to 2 times higher in the inner 1 to 5 mm region surrounding the burrow than in ambient sediment. In contrast, pools of reduced sulfur increased with the distance from the burrow wall to values approximately 1.5 times higher in ambient sediment. The highest numbers of sulfate-reducing bacteria (estimated using a most-probable-number technique) and microbial biomass (estimated from phospholipid phosphorous content) relative to ambient sediment were found in the innermost zone around burrows. Results from an artificial burrow experiment showed that artificial burrow irrigation suppressed sulfate reduction in the innermost zone around burrows, while radial profiles of reduced sulfur resembled those from M. arenaria burrows, indicating loss of reduced sulfur from the burrow wall. M. arenaria burrows are thus sites of enhanced microbial activity and a dynamic sulfur cycle, with turnover times of reduced sulfur compounds increasing with distance from the burrow wall. Enhanced sulfate reduction rates near burrows are likely caused by substrate enrichment, perhaps due to organic excretions from M. arenaria. The pattern of reduced sulfur turnover likely results from periodic oxygen inputs during burrow irrigation.
AN: 4038071
265 of 313
TI: Metabolism and organic carbon fluxes in the tidal freshwater Hudson River
AU: Howarth,-R.W.; Schneider,-R.; Swaney,-D.
AF: Sect. Ecol. and System., Corson Hall, Cornell Univ., Ithaca, NY 14853, USA
SO: ESTUARIES 1996 vol. 19, no. 4, pp. 848-865
NT: Dedicated issue: The Hudson River Estuary. Most papers were presented at 12th ERF conference, Hilton Head I, SC (USA), in 1993.
LA: English
ER: F (Freshwater)
AB: We summarize rates of metabolism and major sources and sinks of organic carbon in the 148-km long, tidally influenced, freshwater Hudson River. The river is strongly heterotrophic, with respiration exceeding gross primary production (GPP). The P:R ratio averages 0.57 (defined as the ratio of GPP to total ecosystem respiration) if only the aquatic portion of the ecosystem is considered and 0.70 if the emergent marshes are also included. Gross primary production (GPP) by phytoplankton averages approximately 300 g C m super(-2) yr super(-1) and is an order of magnitude greater than that by submersed macrophytes. However, the river is deep, well mixed, and turbid, and phytoplankton spend a majority of their time in the dark. As a result, respiration by living phytoplankton is extremely high and net primary production (NPP) by phytoplankton is estimated to be only some 6% of GPP. NPP by phytoplankton and submersed macrophytes are roughly equal (approximately 20 g C m super(-2) yr super(-1) each) when averaged over the river. Emergent marshes are quite productive, but probably less than 16 g C m super(-2) yr super(-1) enters the aquatic portion of the ecosystem from these marshes. Heterotrophic respiration and secondary production in the river are driven primarily by allochthonous inputs of organic matter from terrestrial sources. Rates of metabolism vary along the river, with depth being a critical controlling factor. The P:R ratio for the aquatic portion of the ecosystem varies from 1 in the mid-river to 0.2 in the deeper waters. NPP is actually negative in the downstream waters where average depths are greater since phytoplankton respiration exceeds GPP there; the positive rates of NPP occurring upriver support a downstream advection of phytoplankton to the deeper waters where this C is largely respired away by the algae themselves. This autotrophic respiration contributes significantly to oxygen depletion in the deeper waters of the Hudson. The tidally influenced freshwater Hudson largely fits the patterns predicted by the river continuum model for larger rivers. However, we suggest that the continuum model needs to more clearly distinguish between GPP and NPP and should include the importance of autotrophic respiration by phytoplankton that are advected along a river. The organic carbon budget for the tidally influenced freshwater Hudson is balanced to within a few percent. Respiration (54%) and downstream advection into the saline estuary (41%) are the major losses of organic carbon from the ecosystem. Allochthonous inputs from nonpoint sources on land (61%) and GPP by phytoplankton (28%) are the major sources to the system. Agricultural erosion is the major source of allochthonous inputs. Since agricultural land use increased dramatically in the last century, and has fallen in this century, the carbon cycle of the tidally influenced freshwater Hudson River has probably changed markedly over time. Before human disturbance, the Hudson was probably a less heterotrophic system and may even have been autotrophic, with gross primary production exceeding ecosystem respiration.
AN: 4038025
266 of 313
TI: Monitoring, mass balance calculation of nutrients and the future of the Gulf of Bothnia
AU: Wulff,-F.; Perttilae,-M.; Rahm,-L.
AF: Department of Systems Ecology, Univ. of Stockholm, S-106 91 Stockholm, Sweden
SO: AMBIO 1996 vol. Special Report, no. 8, pp. 27-33
LA: English
ER: B (Brackish)
AB: Based on the intensive hydrochemical measurements of the Gulf of Bothnia Year 1991, descriptions are presented of the regional variations of freshwater and nutrient inputs and hydrographic and nutrient conditions for this particular year. These data are then used to construct nutrient budgets for the Bothnian Sea and Bay, for silicate, inorganic and organic nitrogen and phosphorous. The seasonal variations of internal sources and sinks and advective transports between the basins and with the Baltic proper, show the relative importance and magnitude of biochemical and physical processes for the development of nutrient concentrations in those basins. Annual budget estimates show that the Bothnian Sea appears to function as a very efficient sink for nitrogen and phosphorus. There is a very small exchange of nitrogen with the Baltic proper, in contrast to the large amounts of phosphorus imported and silica exported. Overall N:P ratios show the high rates typical of the Bothnian Bay, which are drastically reduced in the Bothnian Sea, particularly for inorganic nutrients. In spite of the highly variable N/P rations of the different pools, the calculated net transfers of inorganic nutrients into organic matter follow classical Redfield ratios in both basins.
AN: 4034630
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TI: Biogeochemical transformations of nitrogen and phosphorus in the marine environment -- coupling hydrodynamic and biogeochemical processes in models for the Baltic Proper
AU: Savchuk,-O.; Wulff,-F.
CA: Stockholm Univ. [Sweden]. Inst. of Syst. Ecology
SO: SYST.-ECOL.-CONTRIB. STOCKHOLM-SWEDEN 1996 vol. 2, 79 pp
LA: English
ER: M (Marine); B (Brackish)
AB: The Baltic Sea was one of the first areas in the world where large-scale effects of increased inputs of nutrients and toxic substances were recognized. Numerical models simulating complex interactions between physical and biochemical processes are important tools in studying such phenomena at the ecosystem level. With the overall objective to develop a numerical model that describes the biogeochemical cycles of nutrients in the entire Baltic Sea a coupled hydrodynamic-biogeochemical model is presented. The model has evolved in a cooperation between the Swedish research program on the large-scale effects of pollution in the Baltic and the Russian "Project Baltica" and is a development of that presented by Stigebrandt & Wulff (1987). A first submodel describing nitrogen and phosphorous pelagic cycles was given in Savchuk & Wulff 1993. The present model is a development including nitrogen fixation and sediment-water interactions which has been coupled with the hydrodynamic sub-model and implemented for the Baltic. The model was verified by comparing the model results in an analysis with observations from the Baltic showing that the model was capable to reproduce a number of key features of biochemical cycles such as quantitative description of the seasonal, inter-annual and long-term dynamics of nutrients and oxygen; the plausible simulation of seasonal dynamics of plankton variables; the imitation of depth distribution of benthic variables; realistic values of pelagic and benthic biochemical fluxes.
AN: 4034615
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TI: Zooplankton. Pivotal role in the control of ocean production
AU: Banse,-K.
AF: University of Washington, School of Oceanography, Box 357940, Seattle, WA 98195-7940, USA
CA: International Counc. for the Exploration of the Sea, Copenhagen [Denmark]
CO: ICES Symp. on Zooplankton Production, Plymouth (UK), 15-19 Aug 1994
SO: ZOOPLANKTON-PRODUCTION.-PROCEEDINGS-OF-A-SYMPOSIUM-HELD-IN-PLYMOUTH,-ENGLAND,-15-19-AUGUST-1994. Harris,-R.-eds. LONDON-UK ACADEMIC-PRESS 1995 vol. 52, no. 3-4 pp. 265-277
ST: ICES-J.-MAR.-SCI. vol. 52, no. 3-4
NT: Issued also as: ICES Mar. Sci. Symp., v. 200.
LA: English
ER: M (Marine)
AB: The article focuses on the nutrient-depleted (oligotrophic) areas of the oceans, including stratified temperate seas during summer, all showing little temporal change of phytoplankton concentrations. Zooplankton-mediated processes that lead from physically caused, nitrate-fueled new production to total primary production are emphasized. Under oligotrophic conditions, the rate of phytoplankton cell division in the light-saturated part of the euphotic zone depends directly on the rate of nutrient regeneration by the zooplankton; indirectly, it depends on the liberation of dissolved organic matter that provides the bacterial substrate, mainly from "sloppy" feeding of the zooplanton, excretion, and release from feces, and a small contribution from exudation by phytoplankton. The bacterial division rate is low and is inferred as being controlled by supply rate of dissolved organic carbon. The possibility is discussed that, via nutrient regeneration, temperature-controlled zooplankton physiology largely controls the rate of phytoplankton production, given a physically set rate of new production. Phytoplankton-zooplankton interactions are treated briefly for the high nutrient-low chlorophyll regions that also have little temporal change of phytoplankton concentrations, and the open-sea regions with seasonal blooms. All available marine measurements >9 degree C of bulk phytoplankton division rates are plotted on temperature to improve upon Eppley's standard curve for modeling phytoplankton production.
AN: 4034315
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TI: Undersaturation of CH sub(3)Br in the Southern Ocean
AU: Lobert,-J.M.; Yvon-Lewis,-S.A.; Butler,-J.H.; Montzka,-S.A.; Myers,-R.C.
AF: Cooperative Inst. for Res. in Environ. Sci., Boulder, CO, USA
SO: GEOPHYS.-RES.-LETT. 1997 vol. 24, no. 2, pp. 171-172
LA: English
ER: M (Marine)
AB: Dry mole fractions of methyl bromide (CH sub(3)Br) in marine boundary layer air and in air equilibrated with surface water were measured in the Southern Ocean. Saturation anomalies were consistently negative at -36 plus or minus 7%. The observed undersaturations do not support recently published predictions of highly supersaturated Antarctic waters, but instead suggest a net uptake of atmospheric CH sub(3)Br by cold, productive oceans. The observations do not appear to be supported by known chemical degradation rates and present strong evidence for an unidentified, oceanic sink mechanism such as biological breakdown. Our estimate for the global, net, oceanic sink for atmospheric methyl bromide remains negative at -21 (-11 to -32) Gg y super(-1).
AN: 4033778
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TI: A laboratory study of the biogeochemical cycling of Fe, Mn, Zn and Cu across the sediment-water interface of a productive lake
AU: Hamilton-Taylor,-J.; Davison,-W.; Morfett,-K.
AF: Inst. Environ. and Biol. Sci., Lancaster Univ., Lancaster LA1 4YQ, UK
SO: AQUAT.-SCI. 1996 vol. 58, no. 3, pp. 191-209
LA: English
ER: F (Freshwater)
AB: Laboratory incubation experiments were carried out on sediment cores collected from Esthwaite Water, U.K., during April 1987, when the sediments displayed a characteristic surface (1.5 to 2 cm) oxide floc. The experiments were undertaken at 10 degree C, in the dark, under variable redox and pH conditions for periods of similar to 720 h (30 d). In some cases, realistic amounts of decomposing lake algae were added to simulate the deposition of an algal bloom. Pore waters and overlying waters were obtained from the incubated sediment cores at various time intervals and the samples analysed for pH and dissolved Fe, Mn, Zn and Cu by AAS. The results demonstrated that trace metal concentrations at the sediment-water interface can show rapid, pulsed responses to episodic events associated with controlling factors such as algal deposition and mixing conditions. The variations in dissolved Fe and Mn concentrations could generally be explained by their well known redox behaviour. Appreciable loss of Mn from solution under conditions of well-developed anoxia was consistent with adsorption of Mn super(2+) by FeS. Cu and Zn were both rapidly (24 h) released into solution during incubation of sediment cores prior to the development of anoxia in the overlying waters. Their most likely sources were the reductive remobilization of Mn oxides and the decomposition of organic matter. The addition of decomposing algae to a series of cores resulted in even higher interfacial dissolved concentrations of Cu and Zn, probably through acting as a supplementary source of the metals and through increased oxide dissolution. Switching from anoxic to oxic conditions also rapidly increased dissolved Cu and Zn concentrations, possibly due to their release during the oxidation of metal sulphides. The enhanced releases of dissolved Cu and Zn were generally short-lived with removal being attributed to the formation of sulphides during anoxia and to adsorption by Fe and Mn oxides under oxic conditions.
AN: 4032172
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TI: Measured and modeled primary production in the Northeast Atlantic (EUMELI JGOFS program): The impact of natural variations in photosynthetic parameters on model predictive skill
AU: Morel,-A.; Antoine,-D.; Babin,-M.; Dandonneau,-Y.
AF: Lab. de Physique et Chimie Marines, Univ. Pierre et Marie Curie and CNRS, BP 8, F-06230 Villefranche-sur-Mer, France
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1996 vol. 43, no. 8, pp. 1273-1304
LA: English
ER: M (Marine)
AB: Use of ocean color satellite data in global biogeochemical studies requires models to predict primary production from the satellite-derived chlorophyll fields. In this paper, measured bio-optical and photo-physiological data are used in place of standard (constant) parameters to adjust a previously published primary production model. In the JGOFS-France program, systematic studies were carried out at three locations in the tropical northeast Atlantic, selected to represent typical EUtrophic, MEsotrophic and oLIgotrophic regimes (EUMELI cruises). During cruise no. 4, these studies included the spectral measurements of the photosynthetically available radiation at sea level and within the water column, the determination of the algal absorption spectra and the determination of the physiological parameters derivable from P versus E experiments (photosynthesis-irradiance responses). The model predictions are compared with in situ determinations made by the super(14)C technique (JGOFS core parameter). At the three sites, the physical structure (mixed layer and euphotic depths), the algal abundance and community structure, as well as their bio-optical and physiological properties, are very different, so that the predictive performance of the model was tested in trophic conditions that span most of those expected in the global open ocean. The model, when adjusted by entering the actual physiological parameters (chlorophyll-specific absorption of algae, maximum quantum yield, and light saturated carbon fixation rate), provides satisfying results compared to those observed in situ. The relative roles of the physiological parameters are analyzed and sensitivity studies are performed. For global applications, and in the absence of specific information when all seasons and provinces of the world ocean are considered, it will remain necessary for a while to rely on generic models and a selected standard set of physiological properties. The sensitivity studies here presented help in this choice, and a modified set of parameters is proposed and tested. With this set, reconstructed production profiles are close to those determined in the field, and the integrated values are retrieved with no bias and a reduced scatter (18% at one SD) for 17 stations (cruises 3 and 4) and daily production ranging from 0.3 to 2.3 gC m super(-2).
AN: 4029371
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TI: Cycling of high-molecular-weight dissolved organic matter in the Middle Atlantic Bight as revealed by carbon isotopic ( super(13)C and super(14)C) signatures
AU: Guo,-L.; Santschi,-P.H.; Cifuentes,-L.A.; Trumbore,-S.E.; Southon,-J.
AF: Dep. Oceanogr., Texas A&M Univ., 5007 Ave. U, Galveston, TX 77551, USA
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 6, pp. 1242-1252
LA: English
ER: M (Marine); B (Brackish)
AB: Carbon isotopes ( super(13)C and super(14)C) and elemental composition (C and N) in two fractions of colloidal organic matter (COM) were measured to study the origin and cycling of dissolved organic matter (DOM) in the Middle Atlantic Bight (MAB). COM sub(1) (1 kDa-0.2 mu m) was 59% of the bulk DOM in surface Chesapeake Bay waters and decreased to 30-35% in waters of the MAB. COM sub(10) (10 kDa-0.2 mu m), which was the high-molecular-weight (HMW) component of COM sub(1), comprised 3-12% of the bulk DOM, with highest concentrations in Chesapeake Bay waters and the lowest in deep waters in the MAB. Delta super(14)C values of COM sub(1) decreased from nearshore (-21 to +12ppt) to offshore and from surface (-166 to -85ppt) to bottom waters (-400 to -304ppt). Although Delta super(14)C values of surface-water HMW COM sub(10) were generally high (-2 to -7ppt), values for bottom-water COM sub(10) were much lower (-129 to -709ppt). The high Delta super(14)C values in the surface water suggest a particulate origin of pelagic COM, consistent with the contemporary Delta super(14)C values of particulate organic matter (POM). The very low Delta super(14)C values of bottom-water COM sub(10) imply that in addition to the pelagic origin, sedimentary organic C may serve as an important source for the benthic colloids in the bottom nepheloid layer. The general flow direction of organic carbon is from POM to HMW and to LMW DOM. Three colloidal end-members were identified in the MAB as well as in the Gulf of Mexico: estuarine colloids with high Delta super(14)C values, high C:N ratios, and lower delta super(13)C values; offshore surface water colloids with intermediate Delta super(14)C values, lower C:N ratios, and higher delta super(13)C values; and offshore deep-water colloids with low Delta super(14)C values, intermediate C:N ratios, and variable delta super(13)C values.
AN: 4028380
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TI: Biominerals as trace element sinks
AU: Davies,-N.A.; Simkiss,-K.
AF: Sch. Animal and Microbial Sci., Univ. Reading, Reading RG6 2AJ, England, UK
CO: Biomineralization '93: 7. International Symposium on Biomineralization, (Monaco), 17-20 Nov 1993
SO: BIOMINERALIZATION-'-93:-7TH-INTERNATIONAL-SYMPOSIUM-ON-BIOMINERALIZATION.-MONACO-17-20-NOVEMBER-1993. Allemand,-D.;Cuif,-J.-P.-eds. 1996 vol. 14, no. 4 pp. 209-214
ST: BULL.-INST.-OCEANOGR.-MONACO ISBN-2-7260-0179-3 vol. 14, no. 4
LA: English
ER: M (Marine)
AB: Fecal pellets egested by a number of marine organisms contain biominerals in the form of inorganic granules. These granules accumulate a wide range of metal ions both from within the animal and on their passage through the water column. Subsequent ingestion by filter feeding organisms could result in the absorption of these metals and present a pathway for the bioaccumulation of heavy metals and their cycling through the biota. In an experiment involving zinc uptake in mussels (Mytilus edulis) the granules were incubated in sea water containing radioactively labelled zinc and then fed to mussels. Radiolabelled zinc in solution was used as a control to the particulate experiment. The results indicate that zinc in solution is absorbed across the gills and mantle. When in particulate form, the zinc is ingested, passed through the gut, and is absorbed into the digestive gland.
AN: 4026690
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TI: Biological aspects of the long term carbon cycle
AU: Berner,-R.A.
AF: Dep. Geol. and Geophys., Yale Univ., New Haven, CT 06511, USA
CO: Biomineralization '93: 7. International Symposium on Biomineralization, (Monaco), 17-20 Nov 1993
SO: BIOMINERALIZATION-'-93:-7TH-INTERNATIONAL-SYMPOSIUM-ON-BIOMINERALIZATION.-MONACO-17-20-NOVEMBER-1993. Allemand,-D.;Cuif,-J.-P.-eds. 1996 vol. 14, no. 4 pp. 11-22
ST: BULL.-INST.-OCEANOGR.-MONACO ISBN-2-7260-0179-3 vol. 14, no. 4
LA: English
ER: M (Marine)
AB: A computer model (GEOCARB II) of the long term, or multimillion year, global carbon cycle has been constructed that represents the exchange of carbon between sedimentary rocks and the surficial system consisting of the atmosphere + hydrosphere + biosphere. Processes treated quantitatively by the model include weathering of silicate and carbonate rocks and ancient organic matter (kerogen) on the continents, the deposition of carbonate minerals and organic matter in the ocean, and the metamorphic/volcanic/ diagenetic thermal breakdown of carbonates and organic matter, with consequent degassing of CO sub(2), upon deep burial of the sediments. The carbon cycle model enables calculation of paleolevels of atmospheric CO sub(2) over Phanerozoic time (past 600 million years) and results agree well with independent estimates based on measurements of paleosols and sedimentary rocks. Sensitivity analysis indicates that biological effects on CO sub(2) were especially important during certain periods of the Phanerozoic. During the mid Paleozoic vascular plants arose and populated the continents which brought about a large drop in CO sub(2) to balance the acceleration of silicate rock weathering by the plants. Additional Paleozoic drop in CO sub(2) was caused by the enhanced burial during the Carboniferous and Permian of organic matter emanating from land plants. The refractory fraction (eg. lignin) of land plants joined the remains of marine organisms as a principal source for global carbon burial. During the mid-Mesozoic the rise of coccoliths and foraminifera brought about enhanced deposition of CaCO sub(3) in the deep sea. Combined with dissolutive weathering of shallow water limestones on land, this deep water deposition brought about the slow subsequent transfer of CaCO sub(3) from the continents to the deep ocean basins. This in turn resulted in accelerated degassing of CO sub(2) because deep sea sediments have a higher probability of thermal decomposition due to their subduction along plate margins. The question remains whether similar carbonate transfers between shallow platforms and the deep sea occurred during periods older than the oldest remaining seafloor.
AN: 4026689
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TI: The distribution of super(10)Be and super(9)Be in the South Atlantic
AU: Measures,-C.I.; Ku,-T.L.; Luo,-S.; Southon,-J.R.; Xu,-X.; Kusakabe,-M.
AF: Univ. Hawaii at Manoa, Sch. Ocean Earth Sci. and Technol., Dep. Oceanogr., 1000 Pope Rd., Honolulu, HI 96822, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1996 vol. 43, no. 7, pp. 987-1009
LA: English
ER: M (Marine)
AB: Vertical and surface-water distributions of super(10)Be and super(9)Be in the South Atlantic Ocean were studied. The major input of super(9)Be to the surface waters of the region is from the partial dissolution of eolian dusts, with the extent of the dissolution being about seven times that of aluminum from the dust particles. The gradients in surface-water super(10)Be concentrations appear to reflect the magnitude of the local precipitation. The imprinting of the surface water signals onto the deep water masses appears rapid, particularly in regions of enhanced productivity. Bottom waters of Antarctic origin have characteristic isotope signatures that can be traced along their advective route into the Guinea Basin of the eastern Atlantic. Elevated super(9)Be concentrations in the Angola Basin are indicative of diagenetic input in this region of restricted circulation. The corresponding anomalous super(10)Be in the bottom waters indicates historically lower surface-water super(10)Be/ super(9)Be ratios in the region, perhaps as a result of the further southward penetration of the Inter-Tropical Convergence Zone at those times. The budgets of super(10)Be and super(9)Be in the South Atlantic were estimated. The results show that cross-equator transport of super(10)Be and super(9)Be from the North Atlantic is 0.3 plus or minus 10 super(23) atoms/year and 5.7 plus or minus 10 super(6) mol/year, respectively, accounting for less than 5% of super(10)Be and about 10% of super(9)Be entering the North Atlantic. There is a net export across 50 degree S to the Antarctic/Indian/Pacific Oceans of 0.9 plus or minus 10 super(23) atoms/year for super(10)Be and 7.5 plus or minus 10 super(6) mol/year for super(9)Be. Using super(10)Be as a tracer, we evaluate accumulation rates of lithogenic minerals to be 1.7 plus or minus 10 super(14) g/year in the North Atlantic and 4.8 plus or minus 10 super(13) g/year in the South Atlantic. While the North Atlantic rate agrees with the observed eolian dust input, the estimated lithogenic flux in the South Atlantic is about twice the eolian input, suggesting that the riverine input of super(9)Be to the open ocean may become non-negligible in areas of low eolian dust flux.
AN: 4026033
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TI: Wet and dry deposition of nitrogen compounds in the southeast Pacific coast: Montemar, central Chile
AU: Prado-Fiedler,-R.; Fuenzalida,-H.A.
AF: Inst. Oceanologia Montemar, Univ. de Valparaiso, Vina del Mar, Chile
SO: J.-GEOPHYS.-RES.-D-ATMOS. 1996 vol. 101, no. D17, pp. 22845-22853
LA: English
ER: M (Marine)
AB: Atmospheric concentration in the marine boundary layer and direct deposition measurements of total nitrate and ammonium for an eastern South Pacific coastal site on Valparaiso Bay, Chile, were carried out during the period January 1992 through March 1993. Concentrations in air for both nitrogen forms exhibit a seasonal pattern with low values in summer and a pronounced increase in winter, having a mean annual concentration of 32.6 nmol m super(-3) for total nitrate and of 44.8 nmol m super(-3) for total ammonium. Wet deposition is characterized by annual precipitation weighted concentrations of 6.0 and 8.1 mu mol dm super(-3) for nitrate and ammonium, respectively. The main factor regulating wet deposition for both nitrate and ammonium is rainfall amount, so that changes in precipitation amount alone originated by climatological factors can produce changes in their relative deposition levels. Existing climatological pattern determines an overall dominance of dry over wet deposition, with totals of 12.9 and 7.34 mmol m super(-2) per year, the reduced forms of nitrogen being generally more abundant.
AN: 4025125
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TI: In situ analyses of methane oxidation associated with the roots and rhizomes of a bur reed, Sparganium eurycarpum, in a Maine wetland
AU: King,-G.M.
AF: Darling Mar. Cent., Univ. Maine, Walpole, ME 04573, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1996 vol. 62, no. 12, pp. 4548-4555
LA: English
ER: F (Freshwater)
AB: Methane oxidation associated with the belowground tissues of a common aquatic macrophyte, the burweed Sparganium eurycarpum, was assayed in situ by a chamber technique with acetylene or methyl fluoride as a methanotrophic inhibitor at a headspace concentration of 3 to 4%. Acetylene and methyl fluoride inhibited both methane oxidation and peat methanogenesis. However, inhibition of methanogenesis resulted in no obvious short-term effect on methane fluxes. Since neither inhibitor adversely affected plant metabolism and both inhibited methanotrophy equally well, acetylene was employed for routine assays because of its low cost and ease of use. Root-associated methanotrophy consumed a variable but significant fraction of the total potential methane flux; values varied between 1 and 58% (mean plus or minus standard deviation, 27.0% plus or minus 6.0%) with no consistent temporal or spatial pattern during late summer. The absolute amount of methane oxidized was not correlated with the total potential methane flux; this suggested that parameters other than methane availability (e.g., oxygen availability) controlled the rates of methane oxidation. Estimates of diffusive methane flux and oxidation at the peat surface indicated that methane emission occurred primarily through aboveground plant tissues; the absolute magnitude of methane oxidation was also greater in association with roots than at the peat surface. However, the relative extent of oxidation was greater at the latter locus.
AN: 4022730
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TI: Nitrogen cycling networks of coastal ecosystems: Influence of trophic status and primary producer form
AU: Christian,-R.R.; Fores,-E.; Comin,-F.; Viaroli,-P.; Naldi,-M.; Ferrari,-I.
AF: Biol. Dep., East Carolina Univ., Greenville, NC 27858, USA
SO: ECOL.-MODEL. 1996 vol. 87, no. 1-3, pp. 111-129
LA: English
ER: B (Brackish); F (Freshwater)
AB: We have used ecological network analysis to compare nitrogen cycles from five well-researched coastal ecosystems. These included a representative ricefield and two lagoons (Tancada and Encanysada lagoons) in the Ebro River delta, Spain; a region of the Sacca di Goro, a lagoon at the mouth of the Po River, Italy; and a drowned river estuary in North Carolina, USA, the Neuse River estuary. We constructed networks for the various systems and ranked them by trophic status (i.e., degree of eutrophication) using four indices. We then considered the importance of (1) trophic status, (2) growth form of dominant primary producer and (3) water residence time to the intensity and pattern of recycling and to the manner in which the systems can "filter" N. Three indices of flux (rate of import, primary producivity and total systems throughput) gave similar rankings of trophic status among ecosystems with the Italian and U.S. systems being most eutrophic, ricefields next, and then the two Spanish lagoons. Patterns of N export and of cycling within the systems were most closely related to the growth form of dominant primary producers. Phytoplankton, with their rapid turnover rate, foster rapid recycling within the water column and continuous transfer to sediments and export. Submersed and emergent aquatic vegetation and macroalgae create lags and pulses within systems by sequestering N during growth and releasing it during senescence, death and decomposition. Trends in cycling among systems relative to trophic status or water residence appear largely secondary to primary producer growth form.
AN: 4021540
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TI: Molecular microbial ecology manual
AU: Akkermans,-A.D.L.; Van-Elsas,-J.D.; De-Bruijn,-F.J.-(eds.)
SO: DORDRECHT-THE-NETHERLANDS KLUWER-ACADEMIC-PUBLISHERS 1995 507 pp
NT: Price: Dfl. 250, US$ 177.50, pound sterling 112.50.
LA: English
AB: For a long time microbial ecology has been developed as a distinct field within Ecology. In spite of the important role of microorganisms in the environment, this group of 'invisible' organisms remained unaccessable to other ecologists. Detection and identification of microorganisms remain largely dependent on isolation techniques and characterisation of pure cultures. We now realise that only a minor fraction of the microbial community can be cultivated. As a result of the introduction of molecular methods, microbes can now be detected and identified at the DNA/RNA level in their natural environment. This has opened a new field in ecology: Molecular Microbial Ecology. In the present manual we aim to introduce the microbial ecologist to a selected number of current molecular techniques that are relevant in microbial ecology. The first edition of the manual contains 33 chapters and an equal number of additional chapters will be added this year. Since the field of molecular ecology is in a continuous progress, we aim to update and extend the Manual regularly and will invite anyone to deposit their new protocols in full detail in the next edition of this Manual. We hope this book finds its place where it was born: at the lab bench!
AN: 4021236
280 of 313
TI: Carbon budget and network analysis of a high-energy beach/surf-zone ecosystem
AU: Heymans,-J.J.; McLachlan,-A.
AF: Zool. Dep., Univ. Port Elizabeth, Box 1600, Port Elizabeth 6000, South Africa
SO: ESTUAR.-COAST.-SHELF-SCI. 1996 vol. 43, no. 4, pp. 485-505
LA: English
ER: M (Marine)
AB: A carbon budget, compiled for a high-energy beach/surf-zone ecosystem in South Africa, consists of 14 living and two non-living compartments, namely dissolved organic carbon and suspended particulate organic carbon. The living compartments constitute three trophic assemblages; the microbial loop, the interstitial system and the macrofauna. The food web budget was subjected to network analysis to assess the status of the system. Input-output analysis indicated that the microbial loop is the most important trophic assemblage in this system, with the interstitial assemblage second in importance. Lindeman trophic analysis estimated that detritivory amounts to 868 mgC m super(-2) day super(-1) and the detritivory:herbivory ratio is 13:1. Biogeochemical cycle analysis concluded that this system is not under any anthropogenic stress, having a nexus with 48 cycles, three 24-cycle nexuses, a single cycle including 11 compartments, and only seven single-cycle nexuses. Based on global systems' properties, this ecosystem has a high normalized internal ascendency (A sub(i):C sub(i)) which suggests that it is well organized and stable. The system possesses significant internal stability and resistance, a feature that is expected from a physically controlled environment. The relative ascendency (A:C) of this system falls well within the range of relative ascendencies for other systems, being higher than most estuaries but lower than upwelling systems, bays and seas. Overall, this ecosystem is perceived to be unstressed and mature, with the physical control exerted on it providing significant internal stability.
AN: 4017590
281 of 313
TI: Biominerals as trace elements sinks
AU: Davies,-N.A.-W.; Simkiss,-K.
AF: School of Animal and Microbial Sciences, University of Reading, Reading, RG6 2AJ, UK
CO: 7. International Symp. on Biomineralization 93, Monaco (Monaco), 17-20 Nov 1993
SO: BIOMINERALIZATION-93.-7TH-INTERNATIONAL-SYMPOSIUM-ON-BIOMINERALIZATION.-5-BIOMINERALIZATION-AND-GLOBAL-OCEANOLOGY.-6-BIOMINERALIZATION-IN-ENVIRONMENTAL-STUDIES-AND-AQUACULTURE.-7-BIOMINERALIZATION-AND-FOSSIL-DATA. Allemand,-D.-eds.;Cuif,-J.P.-eds. MONACO-MONACO MUSEE-OCEANOGRAPHIQUE 1996 vol. NS 14, no. 4 pp. 209-214
ST: BULL.-INST.-OCEANOGR.-MONACO vol. NS 14, no. 4
LA: English
ER: M (Marine)
AB: Fecal pellets egested by a number of marine organisms contain biominerals in the form of inorganic granules. These granules accumulate a wide range of metal ions both from within the animal and on their passage through the water column. Subsequent ingestion by filter feeding organisms could result in the absorption of these metals and present a pathway for the bioaccumulation of heavy metals and their cycling through the biota. In an experiment involving zinc uptake in mussels (M. edulis) the granules were incubated in sea water containing radioactively labelled zinc and then fed to mussels. Radiolabelled zinc in solution was used as a control to the particulate experiment. The results indicate that zinc in solution is absorbed across the gills and mantle. When in particulate form, the zinc is ingested, passed through the gut, and is absorbed into the digestive gland.
AN: 4015979
282 of 313
TI: Biomineralization 93. 7th International Symposium on Biomineralization. 5 -- Biomineralization and Global Oceanology. 6 -- Biomineralization in environmental studies and aquaculture. 7 -- Biomineralization and fossil data
AU: Allemand,-D.; Cuif,-J.P.-(eds.)
CO: 7. International Symp. on Biomineralization 93, Monaco (Monaco), 17-20 Nov 1993
SO: BULL.-INST.-OCEANOGR.-MONACO. MONACO-MONACO MUSEE-OCEANOGRAPHIQUE 1996 vol. NS 14, no. 4, 432 pp
LA: English
ER: M (Marine)
AB: The papers contained in the 5 th session address the complex interactions of the oceanic carbon dioxide system from a variety of complementary perspectives. A major conclusion to be drawn from this session is that there are great needs and opportunities in determining the fluxes and feedbacks of biomineralizing processes in global geochemical cycles, and the factors that control the sensitivities of these processes to environmental conditions or changes. Biomineralization operates as both cause and effect at all scales, and its significance can be fully appreciated only through the sort of interdisciplinary integration exemplified and encouraged by this Symposium. The topics of the 6 th session elucidate various aspects of biomineralization:1) Variations in structure, growth rates and elemental concentrations in shells of gastropods and bivalves, related to environmental parameters 2) Biomineralization and diseases in molluscan aquacultures 3) Calcification control in pearl cultivation 4) Modifications of bivalve shell structures caused by polydora infections 5) Heavy metal accumulation, and their cycling through the biota, in molluscs, crabs and algae 6) Influence of heavy metal concentrations on coccolith ultrastructure. The 7th session reports the new domains of palaeontology open by the recent improvements in analytical techniques. Understanding the sedimentological behaviour of biominerals, and what happens to these organo-mineral architectures when they enter the geological world is the challenge we now face. This approach will certainly improve our interpretation of fossil data in the chemical sense. It can also help us to obtain more precise information on the characteristics of ancient environments. But although this change in scale of palaeontological investigations is only at its beginning. Presently, the palaeontological study of biominerals offers what is still a highly puzzling panorama. However we can already see that the importance of this molecular-scale palaeontology cannot be over-estimated. From both theoretical and applied stand points, current ideas concerning relationships between life and geological processes, will certainly be transformed as strongly as they have been changed in the past.
AN: 4015955
283 of 313
TI: Rates of microbial degradation of dissolved organic carbon from phytoplankton cultures
AU: Chen,-Wenhao; Wangersky,-P.J.
AF: Sch. Earth and Ocean Sci., PO Box 1700, Univ. Victoria, Victoria, BC V8W 2Y2, Canada
SO: J.-PLANKTON-RES. 1996 vol. 18, no. 9, pp. 1521-1533
LA: English
ER: M (Marine)
AB: Dissolved organic carbon (DOC) decay was measured for samples from cultures of the diatoms Chaetoceros gracilis and Phaeodactylum tricornutum, the flagellate Isochrysis galbana, the dinoflagellate Alexandrium tamarense, and a natural algal assemblage from the Northwest Arm, Nova Scotia, Canada, by a high-temperature catalytic oxidation (HTCO) method. Decay rate constants were determined using first-order reaction kinetics in the multi-G model of Berner (In Early Diagenesis, a Theoretical Approach, Princeton University Press, 1980). Decay rates as high as 0.37 day super(-1) were obtained, which demonstrated that DOC released by phytoplankton might be highly labile to bacterial utilization and could be degraded significantly within hours. Decay rates for most species tested followed much the same pattern, with K sub(01) values around 0.3-0.4, K sub(02) values around 0.03, and K sub(03) and K sub(04) values around 10 super(-3) day super(-1) DOC released by the senescent cells of A. tamarense was found to be essentially bacteria resistant, in contrast to that of the other species tested. The decay of DOC was directly temperature dependent over the 10-20 degree C range. Six methods for DOC preservation were tested. Acidification with HCl and refrigerated storage was demonstrated to be the most convenient and practical method. This method can be used for both short- and long-term preservation of DOC samples containing highly labile organic compounds.
AN: 4015075
284 of 313
TI: Marine biotic responses to environmental change and feedbacks to climate
AU: Denman,-K.; Hofmann,-E.; Marchant,-H.
AF: Inst. Ocean Sci., Canada
SO: CLIMATE-CHANGE-1995-THE-SCIENCE-OF-CLIMATE-CHANGE. Houghton,-J.T.;Meira-Filho,-L.G.;Callander,-B.A.;Harris,-N.;Kattenberg,-A.;Maskell,-K.-eds. NEW-YORK,-NY-USA CAMBRIDGE-UNIVERSITY-PRESS 1996 pp. 483-516
LA: English
ER: M (Marine)
AB: Marine biogeochemical processes both respond to and influence climate. Atmospheric carbon dioxide (CO sub(2)) is the most important greenhouse gas increasing rapidly due to human activities. The oceans contain about 40,000 GtC in dissolved, particulate, and living forms. By contrast, land biota, soils and detritus total about 2200 GtC. Living and dead biogenic matter in the ocean contains at least 700 GtC, almost equal to the amount of CO sub(2) in the atmosphere (about 750 GtC). The increase in atmospheric carbon since pre-industrial times (150 GtC) is equivalent to that cycled through the marine planktonic ecosystem in less than 5 years. Simulation models calibrated with oceanic observations indicate that instead of the pre-industrial atmospheric CO sub(2) concentration of 280 ppmv, the atmospheric concentration of CO sub(2) would have been 450 ppmv in the absence of marine biota. Clearly, it is imperative that we understand the contribution of biogeochemical processes in maintaining the steady state functioning of the ocean carbon cycle. In addition to their importance in the global cycling of CO sub(2), marine organisms are significant sources of climatically active trace gases, especially dimethyl sulphide (DMS). Because of the complexity of biological systems, we cannot yet say whether some likely feedbacks from the marine biota in response to climate related changes will be positive or negative. However improved quantitative understanding is likely within the next decade.
AN: 4012897
285 of 313
TI: A simple modelling approach towards hydrochemical seasonality of major cations in a central Amazonian floodplain lake
AU: Weber,-G.E.; Furch,-K.; Junk,-W.J.
AF: Dep. Ecol. Modelling, UFZ-Cent. for Environ. Res. Leipzig-Halle, Permoserstr. 15, 04318 Leipzig, Germany
SO: ECOL.-MODEL. 1996 vol. 91, no. 1-3, pp. 39-56
LA: English
ER: F (Freshwater)
AB: To identify causes of hydrochemical seasonality, dynamic mass balance models are developed. They describe a hypothetical floodplain lake designed according to literature data supplemented by unpublished data on Lago Camaleao, an island channel lake in the lower Solimoes River. The conservative model accounts for advective and atmospheric cation fluxes, the non-conservative model additionally for biogenic cation fluxes due to growth and decomposition of the macrophyte vegetation. During much of the hydroperiod, seasonal evolutions observed for Na, Ca, and Mg, were in accordance with conservative expectation. Increasing concentrations during falling water were not explained by the conservative model. Differences between predictions of the conservative, and the non-conservative model were negligible. Thus, for the evolution of Na, Ca, and Mg, biogenic fluxes are insignificant. We suggest that cation loading during falling water is caused by an abiotic process. Evolution of K was non-conservative during much of the hydroperiod. Deviations from conservative expectation due to K loading during rising, as well as during falling water, were in accordance with predictions of the non-conservative model. Hence, during rising water, macrophyte-derived influxes of K are the key factor for deviations from conservative expectation. During falling water, however, macrophyte decomposition is still poorly understood, and unknown processes causing Na, Ca, and Mg loadings might also procure additional K loading, and thus biogenic K fluxes might not be the sole cause for increasing concentrations.
AN: 4012081
286 of 313
TI: Sedimentation and carbon flux in a Scottish sea loch, Loch Linnhe
AU: Overnell,-J.; Young,-S.
AF: Dunstaffnage Mar. Lab., P.O. Box 3, Oban, Argyll PA34 4AD, UK
SO: ESTUAR.-COAST.-SHELF-SCI. 1995 vol. 41, no. 3, pp. 361-376
LA: English
ER: M (Marine)
AB: Sediment traps were deployed in the upper basin of Loch Linnhe in 120 m of water at depths of 20, 60, 90 and 110 m below the surface. They were serviced over 13 months during 1991-92 at intervals ranging from a week to a month and the following parameters measured: dry weight and concentrations of carbon, nitrogen and chlorophyll. The average sedimentation rates of total dry weight over a year at 20, 60, 90 and 110 m were 12.4, 20.4, 31.0 and 48.5 g/m super(2)/day respectively. The historical net sedimentation rate, calculated from the depth profile of super(210)Pb, was 12.7 g/m super(2)/day, suggesting that the sedimentation rate at 20 m is probably a good estimate of the present net sedimentation rate. On this basis the (estimated) sedimentation at the sediment surface (120 m) was composed of approximately 80% resuspended material. The estimate of input of organic carbon of phytoplankton origin was based on chlorophyll sedimentation rates and yielded a figure of 0.082 g C/m super(2)/day. A summary diagram indicating our estimate of the pathways of particulate organic carbon is presented.
AN: 4009507
287 of 313
TI: The effect of precipitation chemistry upon anion and cation fluxes from the surface layer of ombrotrophic mires in the UK
AU: Sanger,-L.J.; Billett,-M.F.; Cresser,-M.S.
AF: Dep. Biol. Sci., Hatherly Labs., Univ. Exeter, Exeter EX4 4PS, UK
SO: J.-APPL.-ECOL. 1996 vol. 33, no. 4, pp. 754-772
LA: English
ER: F (Freshwater)
AB: Replicate cores and monoliths (bearing intact vegetation) were sampled from the acrotelm and surface litter layer of ombrotrophic mires across a gradient in precipitation chemistry. Leaves from Calluna vulgaris shrubs growing on the surface of these mires were also sampled. The chemical characteristics of the cores as initially sampled and incident Calluna vulgaris leaves were determined. During a 1-year study the monoliths were subjected to 1200 mm of simulated rainfall of the same chemical composition as they received in the field. Drainage water was analysed periodically for component anions and cations. The results show that changes in the chemical quality of precipitation in the UK has induced changes in the N cycling and base status within the acrotelm, and surface litter layer of ombrotrophic mires. The processes affecting NO sub(3) super(-) and NH sub(4) super(+) concentrations in this layer were not the same. Ammonium concentrations were largely dependent upon ion exchange reactions whereas NO sub(3) super(-) concentrations were more dependent upon biologically mediated processes. The results of the study of total element chemistry in Calluna vulgaris stands showed that leaves contained higher N and lower P and Mg concentrations in areas receiving high concentrations of chemical components, delivered in precipitation associated with industrial and domestic atmospheric emissions. Fluxes of all of the ions from monoliths were highly seasonal, and generally reflected fluctuations in nutrient uptake by the vegetation and the activity of soil microbes and fauna. Unlike NH sub(4) super(+), NO sub(3) super(-) and P were rapidly immobilized in the acrotelm and surface litter layer of mires in areas receiving high H, N and S atmospheric inputs. Total P concentrations in this layer were highest in areas receiving high concentrations of H, N and S in precipitation. This probably reflected the rate of litter decomposition and hence the mineralization of organic-P; and may be linked to the chemical composition of Calluna vulgaris leaves.
AN: 4007180
288 of 313
TI: Effects of plankton dynamics on seasonal carbon fluxes in an ocean general circulation model
AU: Six,-K.D.; Maier-Reimer,-E.
AF: Max-Planck-Inst. fuer Meteorologie, Hamburg, Germany
SO: GLOBAL-BIOGEOCHEM.-CYCLES 1994 vol. 10, no. 4, pp. 559-583
LA: English
ER: M (Marine)
AN: 4006223
289 of 313
TI: Oxidation of cobalt and manganese in seawater via a common microbially catalyzed pathway
AU: Moffett,-J.W.; Ho,-J.
AF: Dep. Mar. Chem. and Geochemistry, Woods Hole Oceanographic Inst., Woods Hole, MA 02543, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1996 vol. 60, no. 18, pp. 3415-3424
LA: English
ER: M (Marine)
AB: Cobalt and manganese uptake onto suspended particles was studied in waters collected from Waquoit Bay, Massachusetts and the upper water column of the Sargasso Sea using radiotracers, coupled with protocols used previously for Mn and Ce to distinguish biological and redox processes. Cobalt uptake onto suspended particles in Waquoit Bay was dominated by microbial oxidation. Moreover, there was a close relationship between Mn(II) and Co(II) oxidation, with Mn(II) specific rates approximately 7-10x faster. Oxidation of each element obeys Michaelis Menten kinetics, with identical values of K sub(m) in a given sample and values of V sub(max) which are 7x higher for Mn. Lineweaver-Burk plots, generated from saturation plots for Co and Mn oxidation at different Mn and Co concentrations, demonstrated competitive inhibition between Co and Mn. The results indicate that both elements are co-oxidized via the same microbial catalytic pathway, and that this is probably an important mechanism for the incorporation of Co into marine Mn oxides. In the Sargasso Sea, by contrast, Mn and Co uptake onto suspended particles were completely decoupled. Cobalt uptake was nonoxidative, biologically mediated, and enhanced by low to moderate levels of light. It is probably due primarily to uptake by phytoplankton. Manganese uptake was almost exclusively oxidative and was inhibited by light even at low intensities. The differences probably reflect a higher biological demand for Co in the Sargasso Sea (Co is a biologically essential element), where Co concentrations are low, and lower activity of Mn oxidizing bacteria. Results suggest that higher specific uptake rates of Co than Mn by phytoplankton in oceanic regimes could result in Co having a geochemistry intermediate between Mn and a more nutrient-type element, such as Zn. Nevertheless, Co and Mn cycling are expected to be closely coupled in regions of high microbial Mn oxidizing activity.
AN: 4006181
290 of 313
TI: Dynamic vs. apparent Redfield ratio in the oceans: A case for 3D-models
AU: Maier-Reimer,-E.
AF: Max Planck-Inst. fuer Meteorologie, Hamburg, Germany
SO: J.-MAR.-SYST. 1996 vol. 9, no. 1-2, pp. 113-120
NT: Special issue: EHUX (Emiliania huxleyi).
LA: English
ER: M (Marine)
AB: A three-dimensional model of global biogeochemical cycles (HAMOCC3) is used to discuss potential explanations for apparent observed deviations from a basin-wide Redfield ratio. Two examples are given in which model information can be taken to close the gaps of incomplete measurements or data analyses. A third example illustrates how the apparent covariation between phosphate and alkalinity is created by the circulation.
AN: 4005970
291 of 313
TI: Nitrogen fixation in the marine environment: Relating genetic potential to nitrogenase activity
AU: Zehr,-J.P.; Braun,-S.; Chen,-Y.; Mellon,-M.
AF: Dep. Biol., Rensselaer Polytechnic Inst., Troy, NY 12180-3590, USA
CO: Symposium on Marine Biology: Molecular and Genetic Advances, Plymouth (UK), Apr 1995
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1996 vol. 203, no. 1, pp. 61-73
LA: English
ER: M (Marine)
AB: Nitrogen fixation can be an important source of nitrogen for biological productivity in the marine environment. Biological nitrogen fixation is catalyzed by the enzyme nitrogenase, which is possessed by diverse microorganisms representing virtually all phylogenetic groups. Interest in nitrogen fixation in the sea has usually been focused on rates of nitrogen fixation, but information on the types of species present with the capability for nitrogen fixation can be important for predicting nitrogen fixation rates in situ. Molecular tools for detection and characterization of the nitrogenase (nif) genes and immunoassays for nitrogenase protein can provide new information on the factors regulating the distribution and activity of diverse nitrogen fixing organisms in the marine environment. Amplification and characterization of nifH sequences has made it possible to identify the type(s) of organism responsible for nitrogen fixation, such as in aggregates of the cyanobacterium Trichodesmium. Differences in nitrogen fixation patterns have been linked to genetic differences between Trichodesmium strains. Further development of these approaches will provide new and powerful ways to link the genetic potential for nitrogen fixation to nitrogen fixation rates in the ocean.
AN: 4003712
292 of 313
TI: Carbon, nitrogen and sulfur cycling in sediments of the Ao Nam Bor mangrove forest, Phuket, Thailand: A review
AU: Kristensen,-E.; Holmer,-M.; Banta,-G.T.; Jensen,-M.H.; Hansen,-K.
AF: Institute of Biology, Odense University, DK-5230 Odense M, Denmark
SO: RES.-BULL.-PHUKET-MAR.-BIOL.-CENT. 1995 no. 60, pp. 37-64
NT: Includes bibliogr.: 124 refs.
LA: English
ER: M (Marine); B (Brackish)
AB: An attempt is made to review available data on sediment biogeochemistry of the Ao Nam Bor mangrove forest on the east coast of Phuket Island, Thailand. Aspects of sedimentary carbon, sulfur and nitrogen cycling are evaluated and compared in 3 intertidal zones: 1) The low-intertidal, non-vegetated mudflat outside the forest; 2) The mid-intertidal forest zone with dense growth of Rhizophora apiculata; and 3) The high-intertidal sparsely vegetated zone with high abundance of crab burrows. By compiling data on organic carbon and nitrogen input to (e.g. litterfall, benthic primary production) and output from (e.g. crab ingestion, microbial mineralization, plant assimilation) the sediment, preliminary budgets for the 3 intertidal zones at Ao Nam Bor may be established. However, the presented budgets have serious limitations caused by a general lack of data. In cases where no data are available from Phuket, results are either extrapolated from other mangrove forests, estimated based on assumptions or simply ignored. Furthermore, as most data on benthic carbon and nitrogen cycling used in the budgets are obtained only during the dry season, the carbon budgets most certainly do not represent annual averages, but should rather be considered dry season averages.
AN: 4001132
293 of 313
TI: Methylated arsenic in the southern North Sea
AU: Millward,-G.E.; Kitts,-H.J.; Comber,-S.D.W.; Ebdon,-L.; Howard,-A.G.
AF: Dep. Environ. Sci., Univ. Plymouth, Plymouth PL4 8AA, Devon, UK
SO: ESTUAR.-COAST.-SHELF-SCI. 1996 vol. 43, no. 1, pp. 1-18
LA: English
ER: M (Marine)
AB: Water samples collected in the southern North Sea in August 1988 (mid-summer), April 1989 (spring), September/October 1989 (late summer) and May 1990 were analysed for dissolved inorganic arsenic, monomethylarsenic (MMA) and dimethylarsenic (DMA). In mid-summer 1988, both MMA and DMA were observed throughout the southern North Sea, with lowest concentrations of dissolved inorganic arsenic (mean 6.48 nmol/l) and the highest proportions of methylated arsenic (29%) being found in highly productive continental coastal waters. In April 1989, waters of the North Sea had a mean inorganic arsenic concentration of 12 nmol/l and methylated species were not detected, even though phytoplankton blooms were present. Shipboard phytoplankton incubation studies (in May 1990) revealed that uptake of dissolved inorganic arsenic occurred at a rate of 0.57 nmol/l/day, but the appearance of dissolved methylated species was not observed. During September/October 1989, while MMA and DMA were present in all sectors of the North Sea, the relative proportion of methylated compounds (11%) in continental coastal waters was less than mid-summer 1988. It was shown that estuarine, porewater and atmospheric inputs of arsenic species were relatively small during the observational periods, and that almost all of the methylated compounds originated from decaying algal tissue. Demethylation of DMA and MMA throughout winter contributed to the dissolved inorganic arsenic pool. The results are discussed in the context of the development of a predictive model for the cycling of arsenic in the North Sea.
AN: 3999637
294 of 313
TI: Organism size, life history, and N:P stoichiometry
AU: Elser,-J.J.; Dobberfuhl,-D.R.; MacKay,-N.A.; Schampel,-J.H.
AF: Dep. Zool., Arizona State Univ., Tempe, AZ 85287, USA
SO: BIOSCIENCE 1996 vol. 46, no. 9, pp. 674-684
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Our approach in this article is as follows. First, we describe recent discoveries that establish the importance of consumer body nitrogen:phosphorus (N:P) ratio in modulating secondary production and consumer-driven nutrient cycling in ecosystems. Second, we review aspects of cellular biochemistry and ultrastructure through the eyes of an ecosystem scientist, focusing on the relative nitrogen and phosphorus contents of important biomolecules and cellular structures. Third, we present examples of how organismal characters such as growth rate and ontogeny are linked with biochemical and cellular investment and thus with body N:P ratio. Finally, we propose a general scenario for allometric variation in body N:P ratio among consumers ranging from bacteria to large vertebrates and use the scenario to predict patterns of consumer-driven nutrient cycling and food quality constraints. In the spirit of Reiners (1986), we employ stoichiometric theory as a complementary approach to the study of biological processes, one that we hope will both reinforce conclusions derived from energetic perspectives as well as provide new insights into biological phenomena that may be puzzling when considered from more traditional single-currency approaches.
AN: 3997804
295 of 313
TI: Major biochemical composition of dissolved high molecular weight organic matter in seawater
AU: McCarthy,-M.; Hedges,-J.; Benner,-R.
AF: University of Washington, School of Oceanography, Box 357940, Seattle, WA 98195-7940, USA
SO: MAR.-CHEM. 1996 vol. 55, no. 3-4, pp. 281-297
LA: English
AB: Ultrafiltered dissolved organic matter (UDOM) was isolated from surface, oxygen minimum, and deep waters of three ocean basins and its elemental as well as molecular-level aldose and amino acid compositions were determined. Surface concentrations account for 23-33% of total dissolved organic carbon, and are a factor of 2-3 greater than those in deeper waters. Oceanic UDOM has an extremely characteristic organic composition, clearly distinct from other marine materials such as fresh plankton, sinking particles or humic substances. Polysaccharides appear to be the major reactive component of UDOM. They have a distinctive aldose distribution rich in galactose and deoxy sugar that is almost ubiquitous regardless of depth or location, suggesting that UDOM carbohydrate is dominated by a very similar suite of polysaccharide throughout the ocean. In contrast, amino acids account for a relatively minor component of both total UDOM and of its organic nitrogen component. Amino acid distributions are similar to those from unfractionated seawater, and are not preferentially remineralized.In O2 minimum and deep ocean water, ultrafiltered material accounts for 18-25% of total dissolved organic carbon. Compositions are nearly invariant in these subsurface isolates, suggesting that ultrafiltered material is stable and unreactive throughout the subsurface ocean. Taken together with large compositional differences between UDOM and sinking particles, this observation suggests that dynamic aggregation is probably not an important formation or removal process for UDOM in the deep ocean. Amino acid and especially carbohydrate concentrations are lower in deep UDOM, but the overall molecular-level compositions remain similar to those from surface waters. This molecular-level homogeneity suggests that the UDOM biopolymers reflected in amino acid and carbohydrate data persist relatively unaltered in the deep ocean.
AN: 3997007
296 of 313
TI: Modelling the monthly sea surface
AU: Louanchi,-F.; Metzl,-N.; Poisson,-A.
AF: Laboratoire de Physique et Chimie Marines, URA 2076/CNRS -- Universite Pierre et Marie Curie, case 134, 4 place Jussieu, F-75252 Paris Cedex 05, France
SO: MAR.-CHEM. 1996 vol. 55, no. 3-4, pp. 265-279
LA: English
AB: In order to construct monthly fields of sea surface fugacity of carbon dioxide (fCO2) on a large scale in the Indian Ocean, we use a one-dimensional model which takes into account the main physical and biogeochemical processes controlling fCO2 variations in the ocean. Physical and biogeochemical processes are constrained by the monthly variations of sea surface temperature, salinity, chlorophyll concentration, wind speed and mixed-layer depth. The model is applied to four locations in the Indian Ocean and it well predicts observed temporal variations in fCO2 at these locations. Regarding to monthly fCO2 observations, the model also well simulates the fCO2 distribution and its temporal variations along a track located between 20 degree and 50 degree S with a maximal error of plus or minus 10 mu atm. The model is also used to predict fCO2 for 2 degree x 2 degree grids over the entire Indian Ocean and simulates seasonal cycles that are consistent with observations. The monthly fCO2 fields derived from the model are used to estimate a global air-sea CO2 flux over the Indian Ocean basin. We estimate a net sink of 0.5 Gt/yr C for the Indian Ocean (20 degree N-50 degree S), with the main sink located between 20 degree and 50 degree S.
AN: 3997006
297 of 313
TI: The oceans: A source or a sink of methyl bromide?
AU: Pilinis,-C.; King,-D.B.; Saltzman,-E.S.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Univ. Miami, Miami, FL, USA
SO: GEOPHYS.-RES.-LETT. 1996 vol. 23, no. 8, pp. 817-820
LA: English
ER: M (Marine)
AN: 3992312
298 of 313
TI: Benthic Ba fluxes in the central Equatorial Pacific, implications for the oceanic Ba cycle
AU: Paytan,-A.; Kastner,-M.
AF: Scripps Inst. Oceanogr., Univ. California, San Diego, La Jolla, CA 92093-0212, USA
SO: EARTH-PLANET.-SCI.-LETT. 1996 vol. 142, no. 3-4, pp. 439-450
LA: English
ER: M (Marine)
AB: High resolution pore-water dissolved Ba concentration-depth profiles were determined at seven sites across an Equatorial Pacific productivity gradient from 12 degree 8 to 9 degree N, at 140 degree W. These data are important for understanding the physical, chemical, and biological controls on Ba recycling in the ocean, and for evaluating the paleo-oceanographic significance of Ba content in central Equatorial Pacific sediments. Pore-water Ba concentrations at all sites are higher than in the overlying bottom water, leading to a diffusive flux of Ba into the ocean. A pronounced subsurface concentration maximum exceeding barite solubility characterizes the dissolved Ba pore-water profiles, suggesting that the Ba regenerated in the upper few millimeters of sediment is not controlled by barite solubility. A few centimeters down-core Ba concentrations reach a relatively constant value of approximately barite saturation. The benthic Ba flux shows a clear zonal trend, with a maximum between 2 degree S and 2 degree N, most probably due to higher productivity at the equatorial divergence zone, and with lowest values at the southern and northern extremes of the transect. The dissolved Ba flux between 2 degree S and 2 degree N is similar to 30 nmol cm super(-2) yr super(-1) and drops to 6 nmol cm super(-2) yr super(-1) at 12 degree S. Even the lowest fluxes are significantly higher than those previously reported for the open ocean. In the Equatorial Pacific the calculated Ba recycling efficiency is about 70%. Thus, similar to 30% of the particulate Ba flux to the deep ocean is preserved in the sediments, compared with less than 1% for organic carbon and similar to 5% for biogenic silica. Mass balance calculation of the oceanic Ba cycle, using a two-box model, implies benthic Ba fluxes similar to those reported here for a steady-state ocean.
AN: 3985021
299 of 313
TI: Secondary suspend particulate matters and the bioelement loop in sea water columns
AU: Wu,-Yuduan; Chen,-Cimei; Luo,-Xiaohong
AF: Dep. Oceanogr., Xiamen Univ., Xiamen 361005, People's Rep. China
SO: PROCEEDINGS-OF-SYMPOSIUM-OF-MARINE-SCIENCES-IN-TAIWAN-STRAIT-AND-ITS-ADJACENT-WATERS.-TAIWANHAIXIA-JI-LINJINHAIYU-HAIYANGKEXUE-TAOLUNHUI-LUNWENJI Yu,-Xiaoqun-eds. BEIJING-CHINA CHINA-OCEAN-PRESS 1995 pp. 326-332
LA: English
ER: M (Marine)
AB: The increasing discharge of aquaculture and domestic sewages has caused the formation of secondary suspended particulate matters in the nearshore waters. The paper discusses the problem in the following three aspects. (1) the formation mechanism of the secondary suspended particulate matters; (2) The effects of the secondary suspended particulate matters on the kinetics of transformation among various speciations of the bioelements and the level of nutrients in water; (3) The roles of buffering and controlling played by the secondary suspended particulate matters in the geochemical behaviour, processes, fate and cycling of the bioelements in water columns. It is concluded that the process causes potential eutrophication in coastal waters.
AN: 3983240
300 of 313
TI: The chemical structure of the ecological environment in Lake Honghu
AU: Yang,-Handong; Cai,-Shuming
AF: Inst. Geod. Geophys., Acad. Sin., Wuhan 430077, People's Rep. China
SO: ACTA-ECOL.-SIN.-SHENGTAI-XUEBAO 1995 vol. 15, no. 4, pp. 392-398
LA: Chinese
ER: F (Freshwater)
AB: Lake Honghu is a typical shallow lake and rich in aquatic plants in the middle reach of the Yangtze River. It is an example of and important of type wetland in China. This paper reports on the chemical structure of the ecological environment in the lake. In the lake water, Ca super(2+) and HCO sub(3) super(-) are major cation and anion, alkal capacity is rather low, acid capacity is 1.2x10 super(-3)-2.0x10 super(-3)mol/l H super(+). The equilibrium course of carbonates is the basic factor to control the geochemical process of water quality. Aquatic plants in the lake play the role of concentrating C,N,K,Ca and Cd. The sediment profile of the surface is rich in C,N,S,Ca and Cd. The Al content is relatively low in the sediment although there were large amount of aquatic plants. Most of the C exists in the aquatic plants and N, P, K, Ca and Mg exist in the sediment. The sediment compartment serves as a nutrient reserve.
AN: 3983146
301 of 313
TI: Spatial patterns in phytoplankton biomass and pigment distributions in the Ross Sea
AU: DiTullio,-G.R.; Smith,-W.O.,Jr.
AF: Grice Mar. Biol. Lab., Univ. Charleston, Charleston, SC 29401, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1996 vol. 101, no. C8, pp. 18467-18477
NT: Special section: Biogeochemical cycling in the Ross Sea.
LA: English
ER: M (Marine)
AB: The distribution of phytoplankton biomass and pigments was determined in the Ross Sea during late austral summer 1992. Large gradients in biomass were noted both in the east-west and north-south direction, with maximum particulate matter concentrations occurring in the southwest portion of the Ross Sea. Two xanthophyll pigments dominated the profiles, fucoxanthin (indicative of diatoms) and 19' hexanoyloxyfucoxanthin (hex) (indicative of the prymnesiophyte Phaeocystis antarctica). Fucoxanthin concentrations were greatest near the coast of Victoria Land and within the northern transect, whereas hex concentrations were highest offshore in the SE Ross Sea. Particulate carbon:chlorophyll a (POC:chl) ratios in diatom-dominated waters of the western Ross Sea were relatively high (210). The POC:chl ratio for Phaeocystis antarctica populations from the SE Ross Sea was substantially less (92) than the ratios observed in diatom-dominated waters. Pigment super(14)C labeling indicated that phytoplankton carbon in the diatom-dominated northern Ross Sea accounted for approximately 30% of the POC, with a phytoplankton C:chl ratio of 130. Short-term (24 hour) vertical fluxes of pigments ranged from 3 to 40 mu g chl a m super(-2) d super(-1). Diatom-dominated regions had greater fluxes of phaeophorbides, suggesting that metazoans were the most important grazers at these locations. In contrast, the phaeophytin/total phaeopigment ratio was highest in waters dominated by Phaeocystis antarctica. The distribution of phytoplankton biomass and pigments revealed a spatially variable distribution of taxa, one which clearly has important consequences to food-web dynamics, biogeochemical cycles, and vertical flux patterns in the Ross Sea.
AN: 3982064
302 of 313
TI: Influence of temperature on pathways to methane production in the permanently cold profundal sediment of Lake Constance
AU: Schulz,-S.; Conrad,-R.
AF: Max-Planck-Inst. fuer Terrestrische Mikrobiologie, Karl-von-Frisch-Str., D-35043 Marburg, Germany
SO: FEMS-MICROBIOL.-ECOL. 1996 vol. 20, no. 1, pp. 1-14
LA: English
ER: F (Freshwater)
AB: The in situ temperature of the profundal sediment of Lake Constance is constant at 4 degree C. Methanogenic bacteria could not be detected at 6 degree C by the most probable number (MPN) technique using acetate and H sub(2)/CO sub(2) as methanogenic substrates. Instead, homoacetogenic bacteria were detected on H sub(2)/CO sub(2). At a higher temperature of 20 degree C, however, methanogenic bacteria were found in numbers of about 10 super(5) cells ml super(-1) with H sub(2)/CO sub(2) and about 5 x 10 super(4) cells ml super(-1) with acetate. However, CH sub(4) production was observed at both 4 degree C and 20 degree C. Production of CH sub(4) was inhibited by chloroform and fluoroacetate and the accumulation of intermediary metabolites was measured. At the in situ temperature of 4 degree C, only acetate accumulated in presence of chloroform. Hydrogen partial pressures were at the same low value of about 0.5 Pa as in the uninhibited control. The amount of accumulated acetate was similar to that of CH sub(4) in the uninhibited controls. Similar results were obtained with fluoroacetate which inhibits methanogenesis from acetate. Addition of H super(14)CO sub(3) super(-) did not result in the formation of super(14)CH sub(4) after 28 days of incubation. However, [2- super(14)C]acetate was immediately converted to super(14)CH sub(4). The results indicate that methanogenesis at 4 degree C was exclusively due to acetate cleavage. At 20 degree C, by contrast, accumulation of H sub(2) was observed in addition to that of acetate, propionate, valerate, caproate, methanol and isopropanol, when CH sub(4) production was inhibited by chloroform. Thermodynamic calculations indicated that the accumulation of the fatty acids was a consequence of feedback inhibition by the accumulated H sub(2). Balance calculations indicated that at 20 degree about 22% of the CH sub(4) originated from reduction of CO sub(2). Experiments with H super(14)CO sub(3) super(-) indicated that about 33% of the CH sub(4) originated from H sub(2)/CO sub(2) at 20 degree C. Thermodynamic calculations showed that homoacetogenesis from H sub(2)/CO sub(2) was endergonic, whereas methanogenesis from acetate or H sub(2)/CO sub(2) was exergonic at both 4 degree C and 20 degree C. Low sediment temperatures obviously limited methanogenesis from H sub(2)/CO sub(2) for reasons other than thermodynamics. Simultaneously, degradation processes seemed to be dominated by homoacetogenic degradation of organic matter followed by acetoclastic methanogenesis. However, increase of temperature resulted in a dramatic shift of the degradation pathway enhancing the role of H sub(2) as an intermediate.
AN: 3981616
303 of 313
TI: Depth profile of sulfate-reducing bacterial ribosomal RNA and mercury methylation in an estuarine sediment
AU: Devereux,-R.; Winfrey,-M.R.; Winfrey,-J.; Stahl,-D.A.
AF: Microbial Ecol., Gulf Ecol. Div., Natl. Health and Environ. Effects Res. Lab., U.S. Environ. Prot. Agency, 1 Sabine Island Dr., Gulf Breeze, FL 32561, USA
SO: FEMS-MICROBIOL.-ECOL. 1996 vol. 20, no. 1, pp. 23-31
LA: English
ER: B (Brackish)
AB: The community structure of complex anaerobic microbial communities has been difficult to elucidate because of an inability to cultivate most of the contributing populations. In this study, the distribution of sulfate-reducing bacteria (SRB) in anaerobic sediments was determined using oligonucleotide probes complementary to the 16S ribosomal RNAs of major phylogenetic groups. Sediment cores were collected from Santa Rosa Sound in northwest Florida, and sectioned by depth into 1 to 2 cm fractions. Nucleic acids were extracted from each fraction and hybridized with the SRB-specific ribosomal RNA probes. SRB ribosomal RNAs accounted for almost 5% of the microbial community ribosomal RNA pool in the 3-4 cm depth fraction and were dominated by Desulfovibrionaceae ribosomal RNA. The SRB ribosomal RNA peak coincided with mercury methylation, an activity attributed to SRB. Profiles of the ribosomal RNAs indicate that SRB populations in sediments are stratified by depth.
AN: 3981615
304 of 313
TI: The role of the vertical fluxes of particulate organic matter and calcite in the oceanic carbon cycle: Studies using an ocean biogeochemical general circulation model
AU: Yamanaka,-Y.; Tajika,-E.
AF: Cent. for Climate System Res., Univ. Tokyo, Tokyo, Japan
SO: GLOBAL-BIOGEOCHEM.-CYCLES 1996 vol. 10, no. 2, pp. 361-382
LA: English
ER: M (Marine)
AN: 3980638
305 of 313
TI: The super(13)C Suess effect in the world surface oceans and its implications for oceanic uptake of CO sub(2): Analysis of observations at Bermuda
AU: Bacastow,-R.B.; Keeling,-C.D.; Lueker,-T.J.; Wahlen,-M.
AF: Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093, USA
SO: GLOBAL-BIOGEOCHEM.-CYCLES 1996 vol. 10, no. 2, pp. 335-346
LA: English
ER: M (Marine)
AN: 3980635
306 of 313
TI: Biogeochemical cycling in the Ross Sea: An introduction
AU: Marra,-J.
AF: Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1996 vol. 101, no. C8, pp. 18453-18454
NT: Special section: Biogeochemical cycling in the Ross Sea.
LA: English
AB: The primary aim of biogeochemical cycling in the Ross Sea is to understand the relationship between surface production and sediment preservation. Background for the Biogeochemical Cycling in the Ross Sea program is presented by DeMaster et al. [1992]. The Ross Sea, like much of the Southern Ocean, exhibits a high percentage of opal in the sediments and is a major repository of biogenic silica in the world ocean. Does this represent high fertility of the surface layer? What relative fraction of organic carbon and biogenic silica produced at the surface is preserved in the sediments?
AN: 3979597
307 of 313
TI: Aerosol emissions by tropical forest and savanna biomass burning: Characteristic trace elements and fluxes
AU: Echalar,-F.; Gaudichet,-A.; Cachier,-H.; Artaxo,-P.
AF: LISA - URA CNRS 1404, Univ. Paris 7 et Paris 12, Creteil, France
SO: GEOPHYS.-RES.-LETT. 1995 vol. 22, no. 22, pp. 3039-3042
LA: English
AN: 3976977
308 of 313
TI: The role of organic matter in controlling copper speciation in precipitation
AU: Spokes,-L.J.; Campos,-M.L.A.M.; Jickells,-T.D.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: ATMOS.-ENVIRON. 1996 vol. 30, no. 23, pp. 3959-3966
LA: English
ER: F (Freshwater)
AB: Organic complexation has been suggested to be an important mechanism by which the biogeochemistry of transition metals is altered in natural waters. We have conducted complexing ligand titrations on rainwater, collected during the winter and spring from a semi-urban U.K. location, using cathodic stripping voltammetry with tropolone as the added ligand. The results show that organic ligands capable of binding copper are present in all the precipitation samples measured. As a consequence of the method used, only those copper-natural ligand complexes with conditional stability constants (1:1 stoichiometry-log K' sub(CuL)) between 11 and 14 have been identified. Within this stability region, ligand concentrations vary from 10.2 to 34.5 nM, very similar to the total copper levels which range between 10.2 and 33.2 nM. While total copper has a concentration of the order of 10 super(-8) M, free Cu super(2+) ions exist at levels of just 10 super(-11)-10 super(-12) M, showing that copper is largely complexed in the rainwater samples measured. The existence of such low free ion concentrations must be considered when assessing the catalytic role of rain and aerosol trace metals in atmospheric reactions and determining the impact of atmospheric inputs on surface water biogeochemistry. Conditional stability constants increase with the detection window used (from log K' sub(CuL) = 11.4 at a detection window centred at log alpha sub(CuAL) = 2.68 to log K' sub(CuL) = 12.57 at log alpha sub(CuAL) = 4.47). As the method is specific to a limited range of conditional stabilities, dependent on the strength and amount of competitive ligand used, this concentration dependence suggests the presence of a wider range of natural ligands than those identified here. The source of the organic complexant in precipitation is unclear. We postulate, based on stable isotope measurements made on rains collected at the same location, that the organic ligands are likely to be terrestrial in origin.
AN: 3976279
309 of 313
TI: Preservation efficiencies and accumulation rates for biogenic silica and organic C, N, and P in high-latitude sediments: The Ross Sea
AU: DeMaster,-D.J.; Ragueneau,-O.; Nittrouer,-C.A.
AF: Dep. Mar., Earth, and Atmos. Sci., North Carolina State Univ., Raleigh, NC 27607, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1996 vol. 101, no. C8, pp. 18501-18518
NT: Special section: Biogeochemical cycling in the Ross Sea.
LA: English
ER: M (Marine)
AB: Rates of biogenic sediment accumulation (biogenic silica and organic C, N, and P) and pore water flux have been established for a variety of depositional environments in the Ross Sea. On the basis of super(14)C measurements in kasten cores, sediment accumulation rates ranged from 250 cm kyr super(-1) in the coastal basin of Granite Harbor to 1-2 cm kyr super(-1) in the shelf and slope environments of the northern and eastern Ross Sea. Burial of biogenic material was most rapid in the southwestern Ross Sea, where biogenic silica accumulation rates ranged from 2 to 31 g cm super(-2) kyr super(-1) and organic carbon accumulation rates ranged from 0.05 to 1.4 g cm super(-2) kyr super(-1). In the northern and eastern Ross Sea, biogenic silica and organic carbon accumulation rates typically equaled 0.02-0.03 g SiO sub(2) cm super(-2) kyr super(-1) and 0.002-0.004 g C cm super(-2) kyr super(-1). Flux core measurements were used to estimate seabed regeneration rates for biogenic silica, organic carbon, and phosphorus. Pore water fluxes, in general, showed much less variability across the Ross Sea than did the biogenic accumulation rates. Pore water silicate fluxes in the study area ranged from 0.6 to 5.3 g SiO sub(2) cm super(-2) kyr super(-1), whereas carbon fluxes ranged from 0.1 to 1.2 g C cm super(-2) kyr super(-1) and phosphate fluxes varied from -0.006 to 0.012 g P cm super(-2) kyr super(-1). Seabed preservation efficiencies were calculated for biogenic silica, organic carbon, and phosphorus by combining the solid-phase and pore water data. The seabed preservation efficiencies for biogenic silica (1-86%) were greater than for organic carbon (1-71%) at all nine stations examined. The preferential preservation of biogenic silica relative to organic carbon also was apparent in Ross Sea sediments because the biogenic silica/organic carbon ratio in the material buried in the seabed generally was 2 times greater than the ratio in sediment particles arriving at the sediment-water interface. Sediment accumulation rate correlated strongly with both the biogenic silica and the organic carbon preservation efficiency data. P preservation efficiencies remained relatively high (24-65%) even when the accumulation rates were low (1-2 cm kyr super(-1)) because of the near-zero phosphate fluxes out of the seabed. Of the total P in the seabed (0.04-0.09 wt. %), approximately 25% existed in the form of organic P. The total amount of biogenic silica accumulating on the Ross Sea shelf is similar to 2.3 x10 super(12) g SiO sub(2) yr super(-1), which is approximately an order of magnitude less than the Ledford-Hoffman et al. [1986] estimate that was based on super(210)Pb chronologies. Biogenic silica accumulation rates in the southern, central, and western Ross Sea increased during the mid and late Holocene, reaching their maximum values during the past 500 to 1000 years.
AN: 3975737
310 of 313
TI: Cycling of organic carbon and biogenic silica in the Southern Ocean: Estimates of water-column and sedimentary fluxes on the Ross Sea continental shelf
AU: Nelson,-D.M.; DeMaster,-D.J.; Dunbar,-R.B.; Smith,-W.O.,Jr.
AF: Coll. Oceanic and Atmos. Sci., Oregon State Univ., Corvallis, OR 97331, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1996 vol. 101, no. C8, pp. 18061-18077
NT: Special section: Biogeochemical cycling in the Ross Sea.
LA: English
ER: M (Marine)
AB: We examined the cycling of organic carbon and biogenic silica in the water column and upper sediments of the Ross Sea, seeking to understand the processes leading to the formation of opal-rich, organic-poor sediments over much of the Southern Ocean. Between January, 1990 and December, 1994 we conducted three cruises, performing tracer incubation studies ( super(14)C, super(15)N, super(30)Si, super(32)Si) to measure rates of primary production, nitrate-based "new" production, biogenic silica production and biogenic silica dissolution in the upper 50 m over most of the Ross Sea shelf in spring, mid summer and late summer. We deployed sediment traps from January, 1990 to early March, 1992 to measure the mid-water (250 m) and near-bottom gravitational fluxes of particulate organic carbon, nitrogen and biogenic silica year-round at three sites, and obtained sediment cores at 15 sites to assess the accumulation rates of organic carbon and biogenic silica in all known sediment regimes on the shelf. At 9 of those sites we also measured nutrient efflux from the sediments, enabling us to calculate benthic recycling fluxes of organic matter and opal. These data permit estimates of the annual production, near-surface recycling, vertical sinking flux, delivery to the seabed, benthic regeneration and long-term burial of both organic and siliceous material, integrated over a 3.3 x 10 super(5) km super(2) area that covers 75-80% of the Ross Sea shelf. The resulting annual budgets for carbon and silica indicate highly selective preservation of biogenic silica over organic carbon between 50 and 250 m in the water column, as well as in the upper seabed. Selective preservation of silica within the upper 50 m is not indicated, and both organic matter and silica are transported from 250 m to the sea floor with virtually 100% efficiency. The SiO sub(2)/C mass ratios for surface-layer production, 250-m sinking flux, delivery to the seabed and long-term burial are approximately 0.85, 6.1, 6.2 and 27, respectively. This progressive enrichment in silica results in long-term burial of 5.8% of the biogenic silica and 0.17% of the organic carbon produced by phytoplankton in the surface layer, a factor of 30 greater preservation efficiency for silica than for carbon. Nevertheless, the ratio of opal burial to opal production in the Ross Sea is only about twice the apparent global average of 3% and <1/3 of the estimated burial/production ratio for the Southern Ocean as a whole. It thus appears that both silica preservation and the decoupling between the cycles of silica and carbon must be even more effective in the waters overlying abyssal Southern Ocean sediments than they are over the Ross Sea shelf.
AN: 3975736
311 of 313
TI: Re-evaluation of colorimetric Cl super(-) data from natural waters with DOC
AU: Norton,-S.A.; Handley,-M.J.; Kahl,-J.S.; Peters,-N.E.
AF: Dep. Geol. Sci., Univ. Maine, Orono, ME 04469-5711, USA
SO: WATER,-AIR,-SOIL-POLLUT. 1996 vol. 91, no. 3-4, pp. 283-298
LA: English
ER: F (Freshwater)
AB: Colorimetric Cl super(-) data from natural solutions that contain dissolved organic carbon (DOC) may be biased high. We evaluated aquatic Cl super(-) concentrations in ecosystem compartments at the Bear Brook Watershed, Maine, and from lakes in Maine, using ion chromatography and colorimetry. DOC imparts a positive interference on colorimetric Cl super(-) results proportional to DOC concentrations at approximately 0.8 mu eq Cl super(-)/L per mg DOC/L. The interference is not a function of Cl super(-) concentration. The resulting bias in concentrations of Cl super(-) may be 50% or more of typical environmental values for Cl super(-) in areas remote from atmospheric deposition of marine aerosols. Such biased data in the literature appear to have led to spurious conclusions about recycling of Cl super(-) by forests, the usefulness of Cl super(-) as a conservative tracer in watershed studies, and calculations of elemental budgets, ion balance, charge density of DOC, and dry deposition factors.
AN: 3975030
312 of 313
TI: Biogeochemical cycles of carbon, nitrogen, and silicon, phytoplanktonic dynamics
OT: Cycles biogeochimiques du carbone, de l'azote et du silicium
AU: Delamo,-Y.; Le-Pape,-O.; Queguiner,-B.; Treguer,-P.; Menesguen,-A.; Cann,-P.
AF: URA CNRS 1513, Laboratoire Flux de Matiere et Reponses du Vivant, Institut Europeen de la Mer, UBO, BP 452, 29275 Brest cedex, France
CA: Communaute Urbaine de Brest [France]
CO: Le Programme Rade. 3. Rencontres Scientifiques Internationales, Brest (France), 14-16 Mar 1995
SO: ROADSTED-PROGRAM.-THIRD-INTERNATIONAL-SCIENTIFIC-MEETINGS:-PROCEEDINGS,-BREST-14-15-ET-16-MARCH-1995.-VOL.-1:-JOURNEE-DU-14-MARS-1995.-PROGRAMME-RADE;-3E-RENCONTRES-SCIENTIFIQUES-INTERNATIONALES:-ACTES-DE-COLLOQUE,-BREST-LES-14-15-ET-16-MARS-1995.-VOL.-1:-JOURNEE-DU-14-MARS-1995. BREST-FRANCE COMMUNAUTE-URBAINE 1995 pp. 42-58
LA: French
ER: M (Marine)
AB: The annual cycle of primary production in the Bay of Brest, and the spring species succession of the phytoplankton are presented and discussed, in relation to physical, chemical, and biological features of the environment. The winter stock of nutrients, characterized by, an excess of dissolved inorganic nitrogen as compared to the other nutrient, progressively decreased due to phytoplankton uptake during spring. The dissolved silicate stock exhibited depletion over the whole water column, at the end of the first, diatom dominated, spring bloom (Rhizosoleniaceae), leading to a dinoflagellate increase, including the toxic species (Dinophysis) sp. Later, the course of the productive period is characterized by a sequence of potentialy Si-, N-, and P- limited periods. The subsequent blooms occuring during this period should be supported by regenerated nutrients. During the entire productive period, primary production is dominated by the microplankton fraction. Nevertheless, its account to total production decreased over the season as this fraction got more and more heterotrophic; conversely, pico- and nannoplankton exhibited an increase in their contribution to total primary production. Picoplankton, mainly heterotrophic, exhibited a relatively, stable evolution during the all season, with the exception of an intportatit increase of heterotrophic contpotielits (probably bacteria), during the collapse of the first spring diatom bloom. The nannoplankton appeared as a potentially important contributor to primary production but it decreased rapidly at the beginning of the spring bloom, possibly due to microzooplankton grazing. The cryptophycean population were thus rapidly replaced by small dinoflagellates. In spite of the dissolved inorganic nitrogen overload during winter, the Bay of Brest exhibited no mark of eutrophication, as well by refering to the annual production rate (148 g Cm-2 y-1 in 1993) as compared to earlier studies, as with regards to dissolved oxygen saturation rates ( > 97 % during the all year).
AN: 3973563
313 of 313
TI: Effect of pesticides on hydrogen metabolism of Rhodobacter sphaeroides and Rhodopseudomonas palustris
AU: Chalam,-A.V.; Sasikala,-C.; Ramana,-C.V.; Rao,-P.R.
AF: Microbial Biotechnology Laboratory, Department of Botany, Osmania University, Hyderabad 500 007, India
SO: FEMS-MICROBIOL.-ECOL. 1996 vol. 19, no. 1, pp. 1-4
LA: English
ER: F (Freshwater)
AB: The present study reports the effect of 2,4-D, quinalphos, monocrotophos, captan and carbendazim on the hydrogen metabolism (nitrogenase, photoproduction of hydrogen and hydrogenase activities) of two purple non-sulfur bacteria isolated from paddy soils. In general, the pesticides were found to be inhibitory to both nitrogenase and hydrogen photoproduction activities of both the organisms, and their effect on hydrogenase-mediated reactions varied with the pesticides used and the organisms.
AN: 3972362
No. Records Request
1: 504 BIOGEOCHEMICAL
2: >8530 CYCL*
3: 369 BIOGEOCHEMICAL CYCL*
1 of 369
TI: Estimates of degradable organic carbon in deep-sea surface sediments from super(14)C concentrations.
AU: Emerson,-S.; Stump,-C.; Grootes,-P.M.; Stuiver,-M.; Farwell,-G.W.; Schmidt,-F.H.
AF: Sch. Oceanogr., Quaternary Res. Cent., Univ. Washington, Seattle, WA 98195, USA
SO: NATURE. 1987. vol. 329, no. 6134, pp. 51-53
LA: English
ER: M (Marine)
AB: Organic carbon sources, degradation and burial in surface marine sediments control the exchange of this carbon pool with that in the ocean and provide the key to understanding the response of the sedimentary reservoir to changing environmental conditions. The authors explore these subjects by organic-carbon concentration profiles and newly determined radiocarbon activities from three deep-water locations. Results suggest that the bulk of the organic matter in the surface mixed layer of marine sediments has a planktonic origin, and up to 50% of this reservoir is degradable on a timescale of less than or equal to 1,000 yr; short enough to have responded to glacial interglacial changes. The degradable fraction is estimated to be presently 50 plus or minus 15 x 10 super(15) g C and may have been several times larger during the past glacial period.
AN: 1604658
2 of 369
TI: The use of mass balances to test and improve the estimates of carbon fluxes in an ecosystem.
AU: Klepper,-O.; Van-de-Kamer,-J.P.G.
AF: Delta Inst. Hydrobiol. Res., Vierstr. 28, 4401 EA Yerseke, Netherlands
SO: MATH.-BIOSCI. 1987. vol. 85, no. 1, pp. 37-49
LA: English
ER: B (Brackish)
AB: A method is presented to analyse the estimates of carbon fluxes in an ecosystem by demanding that (1) the carbon budget of each ecological group should be balanced and that (2) every carbon flux in these balanced budgets should fall within the range of experimentally obtained values. It is shown that the problem of finding an optimal balanced solution is equivalent to the solution of an overdetermined linear system in the Chebyshev norm. The method is illustrated with a small prototype model. Some results are shown of the analysis of a large data set from the Oosterschelde estuary, S.W. Netherlands. The results indicate that the method is powerful in reducing the uncertainties of fluxes. The method proves to be a useful tool both for decreasing the uncertainty of estimated fluxes without additional field work and (by indicating inconsistent or inconclusive data) for directing further research. In particular, consistency is a prerequisite for any simulation modeling effort.
AN: 1604644
3 of 369
TI: Biogeochemical cycling of metals in Barataria Basin.
AU: Feijtel,-T.C.J.
CA: Louisiana State Univ. and A&M Coll., Baton Rouge (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1987. vol. 47, no. 8, 303 pp
NT: Diss. Ph.D.: Order No. FAD DA8625334.
LA: English
ER: M (Marine); B (Brackish)
AB: Metal distribution, accumulation, and differential mobility were determined in the terrestrial and aquatic portions of Barataria Basin. Seasonal variations in surface water and interstital pore water constituents of marsh and bay bottom sediments, along a salinity transect were determined through a monthly sampling from March 1984 to August 1985.
AN: 1604176
4 of 369
TI: Organic carbon cycle in oceans.
OT: Tsikl organicheskogo ugleroda v okeanakh
AU: Wangersky,-P.J.
AF: Dalhousie Univ., Halifax, N.S., Canada
SO: EHKOL.-MORYA. 1986. no. 24, pp. 3-24
NT: Incl. bibliogr.: 189 ref.
LA: Russian
ER: M (Marine)
AB: The present-day oceanographic literature (mainly English-language) devoted to different aspects of carbon exchange in the marine environment is reviewed. Main sources and flows of different organic carbon forms - mineral, organic, living, dead - as well as main changes in conceptual picture of the carbon exchange in marine environment are considered. An increasing scientific significance is emphasized for the data on rates of different processes, especially of primary production, sedimentation of suspensions, bacterial processes.
AN: 1604035
5 of 369
TI: Technetium distribution and accumulation in marine sediments and biota.
AU: Schulte,-E.H.
AF: CEC, c/o ENEA, La Spezia, Italy
SO: BEHAVIOUR-OF-LONG-LIVED-RADIONUCLIDES-ASSOCIATED-WITH-DEEP-SEA-DISPOSAL-OF-RADIOACTIVE-WASTES.-REPORT-OF-A-CO-ORDINATED-RESEARCH-PROGRAMME-ORGANIZED-BY-THE-INTERNATIONAL-ATOMIC-ENERGY-AGENCY,-1982-1984. International-Atomic-Energy-Agency,-Vienna-Austria 1986. pp. 133-135
RN: IAEA-TECDOC-368 (IAEATECDOC368)
LA: English
ER: M (Marine)
AB: Technetium normally exists in marine environments as pertechnetate Tc super(VII). However when sediments are reduced and organic rich, it becomes fixed rapidly to them. Bacterial activity does not seem to be responsible. Concentration factors for Tc in biota are generally 10-20 but two exceptions are macrophytic algae (1100) and polychaetes (300-800). Biological half lives are weeks or months. Retention was generally about 20% of that in the food source, and 25% of that was retained in the digestive gland or liver.
AN: 1603762
6 of 369
TI: Biological mixing and radionuclide redistribution in marine sediments.
AU: Schulte,-E.H.
AF: CEC, c/o ENEA, La Spezia, Italy
SO: BEHAVIOUR-OF-LONG-LIVED-RADIONUCLIDES-ASSOCIATED-WITH-DEEP-SEA-DISPOSAL-OF-RADIOACTIVE-WASTES.-REPORT-OF-A-CO-ORDINATED-RESEARCH-PROGRAMME-ORGANIZED-BY-THE-INTERNATIONAL-ATOMIC-ENERGY-AGENCY,-1982-1984. International-Atomic-Energy-Agency,-Vienna-Austria 1986. pp. 115-118
RN: IAEA-TECDOC-368 (IAEATECDOC368)
LA: English
ER: M (Marine)
AB: Literature survey indicates that bioturbation strongly affects the recycyling of radionuclides through the benthic boundary layer, and nuclides such as super(239,240)Pu and super(241)Am may be resolubilized by anionic complexers released by fauna. Transfer of nuclides to fauna which ingest particles is very low, whereas transfer from water is much more efficient. This suggests that interstitial water is probably the predominant source of transuranics for benthic organisms in sediments.
AN: 1603715
7 of 369
TI: Anaerobic dissolution of iron-phosphorus complexes in sediment due to the activity of nitrate-reducing bacteria.
AU: Jansson,-M.
AF: Inst. Geogr., Univ. Umeaa, S-901 87 Umeaa, Sweden
SO: MICROB.-ECOL. 1987. vol. 14, no. 1, pp. 81-89
LA: English
ER: F (Freshwater)
AB: Nitrate-reducing bacteria (Pseudomonas fluorescens and Alcaligenes sp.) as well as extracellular compounds from these bacteria increased the dissolution rate of iron and phosphorus sorbed to iron precipitates during anaerobic, nitrate-free conditions in experimental sediment-water systems. It is suggested that the influence of the bacteria is due to enzymatic catalyzation of chemical iron reduction.
AN: 1603696
8 of 369
TI: Potential rates of nitrification and denitrification in an oligotrophic freshwater sediment system.
AU: Dodds,-W.K.; Jones,-R.D.
AF: Dep. Biol., Univ. Oregon, Eugene, OR 97403, USA
SO: MICROB.-ECOL. 1987. vol. 14, no. 1, pp. 91-100
LA: English
ER: F (Freshwater)
AB: Potential rates of nitrification and denitrification were measured in an oligotrophic sediment system. Nitrification potential was estimated using the CO oxidation technique, and potential denitrification was measured by the acetylene blockage technique. The sediments demonstrated both nitrifying and denitrifying activity. E sub(h), O sub(2), and organic C profiles showed two distinct types of sediment. One type was low in organic C, had high O sub(2) and E sub(h), and had rates of denitrification 1,000 times lower than the other which had high organic C, low O sub(2), and low E sub(h). Potential nitrification and denitrification rates were negatively correlated with E sub(h). This suggests that environmental heterogeneity in denitrifier and nitrifier populations in oligotrophic sediment systems may be assessed using E sub(h) before sampling protocols for nitrification or denitrification rates are established. There was no correlation between denitrification and nitrification rates or between either of these processes and NH sub(4) super(+) or NO sub(3) super(-) concentrations.
AN: 1603449
9 of 369
TI: Conceptual evolution of a model of marine biocoenosis and its metabolism.
OT: Kontseptual'naya ehvolutsiya modeli morskogo biotsenoza i obmena veshchestv v nem
AU: Khajlov,-K.M.
AF: Inst. Biol. Yuzhn. Morej AN Ukr.S.S.R., Sevastopol', USSR
SO: EHKOL.-MORYA. 1986. no. 24, pp. 25-33
LA: Russian
ER: M (Marine)
AB: The present-day biooceanographic literature devoted to different aspects of ecological biochemistry and ecology is reviewed. The general trend in the conceptual evolution of the model of marine biocoenosis implies the development of an initial simplified scheme of a pasture food chain into a complicated scheme in which cycles and momentum flux are no less important than energy metabolism. The main stages of the evolution are; 1) extension of knowledge on the role and dynamics of detritus; 2) studies of C escape into the medium in the form of mineral and dissolved organic metabolites; analysis of C regeneration and cycles; 4)special attention to groups of small organisms such as phemto-, pico- and nannoplankton and complicated exzometabolic relationships within and between the groups.
AN: 1601358
10 of 369
TI: The biogeochemical cycle of mercury: An overview.
AU: Zafiropoulos,-D.
AF: E.R.S., Anapiron Polemou 20, 11621 Athens, Greece
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 168-187
ST: FAO-FISH.-REP. no. 325,supp
NT: Incl. bibliogr.: pp. 183-187. ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: The biogeochemical cycle of mercury in the Mediterranean is reviewed, examining the sources and inputs of mercury, levels in seawater, sediments and marine organisms and transportation and fluxes between interfaces. Areas where further research is needed are detailed.
AN: 1581762
11 of 369
TI: Mercury and methylmercury distribution in sediments and in Mytilus galloprovincialis from Kastela Bay (central Adriatic).
AU: Vukadin,-I.; Tusek-Znidaric,-M.; Byrne,-A.R.; Stegnar,-P.
AF: Inst. Oceanogr. Fish., Split, Yugoslavia
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 163-167
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: An account is given of research conducted on the distribution of mercury and methylmercury in sediments and Mytilus galloprovincialis in Kastela Bay, an area which receives considerable amounts of waste from a chlor-alkali plant, chemical and cement industry was well as from a shipyard and also organic pollution produced by municipalities.
AN: 1581743
12 of 369
TI: The role of biochemical processes in the accumulation of mercury by marine organisms.
AU: Thibaud,-Y.
AF: IFREMER, Cent. Nantes, B.P. 1049, 44037 Nantes Cedex, France
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 150-162
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: The accumulation of mercury in marine populations is discussed with respect to time and correlation with organism weight. Biochemical mechanisms involved are examined; it is believed a neutralization of the toxic methylmercury form occurs. Thus the importance of specifying the different forms of mercury when monitoring quality of marine products is stressed.
AN: 1581730
13 of 369
TI: Chemical and biological distribution of mercury in the North Levantine.
AU: Salihoglu,-I.; Yemenicioglu,-S.
AF: Inst. Mar. Sci., Middle East Tech. Univ., P.O. Box 28, Erdemli, Icel, Turkey
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 140-149
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: The results are presented of sampling analyses of sediments, seawater, tarballs, and organisms in the northern Levantine Basin for mercury. The findings are discussed with respect to the biogeochemical cycle of mercury in the region.
AN: 1581720
14 of 369
TI: Measures to abate and control mercury pollution in the Mediterranean Sea.
AU: Saliba,-L.J.
AF: Mediterranean Action Plan, WHO, Reg. Off. For Europe, Copenhagen, Denmark
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 134-139
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: Mercury pollution in the Mediterranean and public health effects are discussed, considering the identification and monitoring of populations at risk, with respect to methylmercury. Possible measures for the prevention of mercury pollution are examined.
AN: 1581704
15 of 369
TI: Regulation and uptake of labelled iron ( super(55)Fe) and labelled mercury ( super(203)Hg) in the organs and flesh of Tilapia zillii Gerv., living in fresh and saline water conditions.
AU: Saleh,-H.H.
AF: Alexandria Inst. Oceanogr. Fish., Alexandria, Egypt
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 128-133
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Experiments were conducted investigating the regulation of labelled iron and mercury in Tilapia zillii . Findings show that the species, living in fresh or saline water, is able to regulate the uptake of iron. The non-regulation of mercury causes a progressive increase of mercury content in its gills when in saline water and in flesh when in freshwater.
AN: 1581692
16 of 369
TI: Mercury in sediments of the northern Adriatic Sea.
AU: Orio,-A.A.
AF: Dep. Environ. Sci., Univ. Venice, Venice, Italy
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 125-127
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: An account is given of the distribution and source of mercury in the northern Adriatic sediments. The presence of mercury in organisms and seawater is also examined briefly.
AN: 1581681
17 of 369
TI: Preliminary investigation on methylmercury content in bivalves of different size.
AU: Najdek,-M.; Bazulic,-D.
AF: Cent. Mar. Res. Rovinj, "Rudjer Boskovic" Inst., 52210 Rovinj, Yugoslavia
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 122-124
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: An examination was made of methylmercury contents in mussels and oysters classified into size classes. Weight-specific contents were significantly correlated with dry weight. Higher accumulation values were observed in oysters.
AN: 1581664
18 of 369
TI: Sea-birds as indicators of mercury pollution in the Mediterranean.
AU: Leonzio,-C.; Focardi,-S.; Fossi,-C.; Renzoni,-A.
AF: Dep. Environ. Biol., Univ. Siena, Siena, Italy
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 116-121
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: An analysis was made of mercury in migratory water birds of the Mediterranean comparing results of analyses made a few days after survival in winter quarters with those made a few days before the flock's departure for breeding areas. Eggs of species breeding the Mediterranean Basin were also analysed. The liver was found to be the most contaminated organ in the birds, which clearly reflect the amount of mercury available in their feeding grounds.
AN: 1581643
19 of 369
TI: Ecological and human health effects of mercury.
AU: Jerneloev,-A.
AF: IOC/UNESCO, 7 Place de Fontenoy, 75700 Paris, France
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 111-115
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: The toxic effects of methylmercury in humans is discussed, considering sources of exposure and metabolism of the compound in the human body. Effects are primarily manifested in damage of the central nervous system, especially sensory centres. An evaluation is made of potential health effects.
AN: 1581625
20 of 369
TI: Assessment of mercury pollution in coastal marine sediments and in benthic organisms.
AU: Hornung,-H.
AF: Israel Oceanogr. and Limnol. Res. Ltd., Tel Shikmona, P.O.B. 8030, Haifa 31080, Israel
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 104-110
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: An examination was made of mercury levels in sediments and benthos in Haifa and coastal water to assess current state of mercury pollution in the Eastern Mediterranean. Findings show that the mercury released by the chlor-alkali plant in the Bay is retained in the nearby sediments. Benthic organisms show high mercury levels associated with feeding habits and intake during feeding in contaminated sediments Thus the organisms are representative of the environment to which they are exposed and therefore may serve as biological indicators.
AN: 1581605
21 of 369
TI: Chemical forms of mercury in flesh, gills and liver from fish species of different habits from two localities west of Alexandria.
AU: Halim,-Y.; Aboul-Dahab,-P.; El-Rayis,-O.
AF: Oceanogr. Dep., Alexandria Univ., Alexandria, Egypt
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 99-103
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: An investigation was made of total and organic mercury levels in the flesh, gills and liver of various fish from different habitats and trophic levels in El Mex Bay. The highest mercury content was found in Euthynnus alletteratus . Despite interspecific variability observed, the pattern of distribution in the fish tissues is constant, most mercury being concentrated in the liver of all species.
AN: 1581591
22 of 369
TI: A comparative study of mercury contamination in the Tagus Estuary (Portugal) and major French estuaries (Gironde, Loire, Rhone).
AU: Figueres,-G.; Martin,-J.M.; Meybeck,-M.; Seyler,-P.
AF: Ec. Norm. Super., Lab. Geol., 46, rue d'Ulm, 75230 Paris Cedex 5, France
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 78-98
ST: FAO-FISH.-REP. no. 325,supp
NT: 34 ref. ISBN 92-4-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: B (Brackish)
AB: Mercury levels in water, suspended matter and surficial bottom sediments of Tagus Estuary, Portugal are examined and compared to those in 3 French estuaries (Loire, Rhone and Gironde). Findings show the Tagus to be one of the most contaminated estuaries studied; the French estuaries are only slightly polluted, as are many other European and North American estuaries.
AN: 1581571
23 of 369
TI: Bioaccumulation of mercury in some coastal marine fish from Alexandria waters.
AU: El-Nady,-F.E.-S.
AF: Fac. Sci., Alexandria Univ., Alexandria, Egypt
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 74-77
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: Comparison was made of mercury concentrations in Mugil capito, Sparus aurata, Raja miraletus and Solea vulgaris in 2 different environments in Alexandria waters: Eastern Harbour and Abu-Kir Bay. Results showed that the concentration of mercury in all fish species from Abu-Kir Bay was higher than in fish from Eastern Harbour, reflecting the influence of additional sources of runoff from industrial wastes.
AN: 1581526
24 of 369
TI: Total mercury in the coastal marine ecosystem west of Alexandria.
AU: El-Rayis,-O.A.; Halim,-Y.; Aboul-Dahab,-O.
AF: Fac. Sci., Alexandria Univ., Alexandria, Egypt
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 58-73
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: A study was undertaken in El-Mex Bay to determine the mercury levels in water, suspended matter, plankton, sediments and fish. The pattern of distribution of mercury indicates that suspended particulate matter is the main vehicle for mercury from land-based sources to the bay, the particulate form representing 88% of the total input. All fish species greater than 220 mm in length reach or exceed the maximum permissible limit.
AN: 1581511
25 of 369
TI: Occurrence of mercury in the atmosphere and waters of the Mediterranean.
AU: Copin-Montegut,-G.; Courau,-P.; Laumond,-F.
AF: Lab. Phys. Chim. Mar., Univ. Pierre et Marie Curie, 06230 Villefranche-sur-Mer, France
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 51-57
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: A discussion is presented on the occurrence of mercury in the atmosphere and in the sea; levels in Mediterranean waters are considered in particular with respect to measurements made in the Ligurian Sea, Villefranche Bay and various stations during the PHYCEMED cruise in 1983. Findings indicate mercury concentrations to be low in the Mediterranean.
AN: 1581496
26 of 369
TI: A model of mercury accumulation in tuna.
AU: Bernhard,-M.
AF: Cent. Studi Ambiente Mar., ENEA, POB 316, 1-19100 La Spezia, Italy
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 44-50
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: A mathematical model is discussed which gives an indication of how the Mediterranean tunas can reach higher mercury levels than Atlantic tunas. Basic assumptions and equations are outlined and numerical simulation detailed.
AN: 1581488
27 of 369
TI: The biogeochemical cycle of mercury in the Tyrrhenian Sea.
AU: Baldi,-F.
AF: Dip. Biol. Ambient., Univ. Siena, 53100 Siena, Italy
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 29-43
ST: FAO-FISH.-REP. no. 325,supp
NT: 25 ref. ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: Findings are presented of investigations conducted on the mercury distribution in the Mediterranean, particularly the Tyrrhenian Sea, and are discussed with respect to the biogeochemical cycle of mercury, examining sediments, water, particulate matter and benthos levels.
AN: 1581473
28 of 369
TI: Recovery trends in a mercury-polluted marine area.
AU: Bacci,-E.; Baldi,-F.; Bargagli,-R.; Gacci,-C.
AF: Dep. Environ. Biol., Univ. Siena, Via delle Cerchia 3, 53100 Siena, Italy
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 20-28
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: Experiments were undertaken to investigate the origin of mercury in the northern Tyrrhenian Sea facing Rosignano Solvay, Italy, and to assess the mercury pollution in the area using indicator organisms. Data were also used to examine recovery trends.
AN: 1581462
29 of 369
TI: Mercury biogeochemistry in the Mediterranean marine environment: An assessment of contamination.
AU: Aston,-S.R.; Fowler,-S.W.; Whitehead,-N.
AF: Int. Lab. Mar. Radioactivity, c/o Mus. Oceanogr., Monaco, Monaco
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 8-19
ST: FAO-FISH.-REP. no. 325,supp
NT: 35 ref. ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: A review is made of data available on mercury in the Mediterranean marine environment. Water, sediment and pelagic organism concentrations show that there is no clear evidence that there are high ambient mercury levels outside the immediate coastal zone. Reasons for the observed high mercury concentrations in tuna some other pelagic fish remain an enigma.
AN: 1581450
30 of 369
TI: Mercury species in coastal marine organisms from different trophic levels west of Alexandria.
AU: Aboul-Dahab,-O.; Halim,-Y.; El-Rayis,-O.
AF: Fac. Sci., Alexandria Univ., Alexandria, Egypt
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: PAPERS-PRESENTED-AT-THE-FAO-UNEP-WHO-IOC-IAEA-MEETING-ON-THE-BIOGEOCHEMICAL-CYCLE-OF-MERCURY-IN-THE-MEDITERRANEAN,-SIENA,-ITALY,-27-31-AUGUST-1984. FAO,-Rome-Italy 1986. no. 325,supp pp. 1-7
ST: FAO-FISH.-REP. no. 325,supp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: Investigations assessed biological amplification of total mercury and its organic form in marine organisms from different levels in the food chain in the Alexandria coastal ecosystem. Comparable differences in the mercury level were observed in the organisms both for total and organic mercury. In all fish species, most of the mercury in flesh was in the organic forms.
AN: 1581444
31 of 369
TI: Papers presented at the FAO/UNEP/WHO/IOC/IAEA Meeting on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena, Italy, 27-31 August 1984.
CA: FAO, Rome (Italy)
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: FAO-FISH.-REP. 1986. 187 pp
NT: ISBN 92-5-102386-7.
RN: FAO FIRI/R325(suppl) (FIRIR325suppl)
LA: English
ER: M (Marine)
AB: Abstracts of the 21 papers presented at the meeting are cited individually.
AN: 1581428
32 of 369
TI: The input of decomposable organic matter and biomass concentration in the plankton of reservoirs.
AU: Straskrabova,-V.
AF: Hydrobiol. Lab., Inst. Landscape Ecol., Na Sadkach 7, 370 05 Ceske Budejovice, Czechoslovakia
CO: Czechoslovak Conference on Hydrobiology and Water Quality of Reservoirs, Ceske Budejovice (Czechoslovakia), 6 Feb 1984
SO: LIMNOLOGY-OF-CZECHOSLOVAK-RESERVOIRS.-PAPERS-BASED-ON-RESULTS-OF-THE-CZECHOSLOVAK-CONFERENCE-ON-HYDROBIOLOGY-AND-WATER-QUALITY-OF-RESERVOIRS. Straskraba,-M.;Porcalova,-P.-eds. 1986. vol. 17, no. 2 pp. 283-290
ST: LIMNOLOGICA. vol. 17, no. 2
LA: English
ER: F (Freshwater)
AB: The concentration of biomass in the plankton of 3 reservoirs was evaluated. The reservoirs differed substantially in size, mean depth and theoretical flushing rate. Two were regularly sampled for 10 years. The average concentrations of bacteria, phytoplankton and zooplankton during the cold and warm half-year periods were transformed into energetic units. Inputs of decomposable organic substances both from inflow and primary production were expressed in comparable units. Total biomasses were directly correlated to total inputs for both cold and warm seasons, but indirectly correlated to flushing rates. The product of flushing rate and biomass concentration (biomass output) was significantly correlated to the inflow inputs during warm seasons. During cold seasons, the correlation only was significant for the heterotrophic component. Equations for predicting average autotrophic and heterotrophic biomass concentration from the flushing rate and BOD in the inflow were derived.
AN: 1580669
33 of 369
TI: Nitrogen dynamics in lower Narragansett Bay. 2. Phytoplankton uptake, depletion rates of nitrogenous nutrient pools, and estimates of ecosystem remineralization.
AU: Furnas,-M.J.; Smayda,-T.J.; Deason,-E.A.
AF: Australian Inst. Mar. Sci., Townsville, Qld. 4810, Australia
SO: J.-PLANKTON-RES. 1986. vol. 8, no. 4, pp. 755-769
LA: English
ER: M (Marine)
AB: Phytoplankton nitrogen demand in lower Narragansett Bay, Rhode Island, measured during the winter-spring of 1977-78 and summers of 1978 and 1979, is compared with estimates of zooplankton and the benthic nitrogen remineralization drawn from the results of experimental field studies. Measured uptake rates would generally lead to the depletion of available nitrogenous nutrient stocks within hours, and usually exceeded estimates of benthic plus zooplankton remineralization. Additional estimates of nitrogen inputs from sewage and riverine sources appear insufficient to make up the difference.
AN: 1579635
34 of 369
TI: Dissolved organic phosphorus production in surface seawaters.
AU: Orrett,-K.-(deceased); Karl,-D.M.
AF: Dep. Oceanogr., Univ. Hawaii, Honololu, HI 96822, USA
SO: LIMNOL.-OCEANOGR. 1987. vol. 32, no. 2, pp. 383-398
LA: English
ER: M (Marine)
AB: Measurements were made of the accumulation ( super(32)P)DOP during seawater sample incubations with super(32)PO sub(4) super(3) super(-). Accumulation rates (i.e. nCi ( super(32)P)DOP liter super(-1) h super(-1)) were extrapolated to total DOP mass fluxes (i.e. ng P liter super(-1) h super(-1)) with two independent P-assimilation models. The first model assumed that the ( super(32)P)DOP produced had the same specific radioactivity (i.e. nCi super(32)P per ng P) as the total dissolved phosphorus pool measured at the beginning of the incubation period. The second model assumed that the ( super(32)P)DOP produced had the same specific radioactivity as the P contained in recently synthesized RNA. Two North Pacific Ocean stations were investigated in detail. DOP production rates measured in mesotrophic waters off Manzanillo, Mexico, varied substantially with depth and time of day, whereas the production rates measured in the oligotrophic North Pacific Gyre were more constant.
AN: 1572289
35 of 369
TI: The role of suspended matter in the biogeochemical cycles in the Adige River Estuary (northern Adriatic Sea).
AU: Juracic,-M.; Vitturi,-L.M.; Rabitti,-S.; Rampazzo,-G.
AF: Cent. Mar. Res., Rudjer Boskovic Inst., Bijenicka 54, 41000 Zagreb, Yugoslavia
SO: ESTUAR.-COAST.-SHELF-SCI. 1987. vol. 24, no. 3, pp. 349-362
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Suspended matter and sediments from the Adige River mouth were analysed in an attempt to elucidate the transfer of heavy metals from the river to the sea. The vertical profile of grain-size spectra of suspended matter in front of the river mouth has shown that the riverine particles are limited to the upper brackish layer. The observed similarity of physico-chemical, mineralogical and geochemical characteristics of riverine suspended matter and recent marine sediments, indicates that most of the riverborne particulate matter is deposited in the proximity of the Adige River mouth.
AN: 1554811
36 of 369
TI: Technical recommendations for studying the biogeochemical cycle of trace metals.
AU: Amiard-Triquet,-C.; Metayer,-C.; Amiard,-J.C.
AF: Cent. Dosage Elements Traces, UER Sci. Pharm., Univ. Nantes, 1 rue Gaston Veil, 44035 Nantes Cedex, France
SO: REV.-INT.-OCEANOGR.-MED. 1984. no. 73-74, pp. 27-34
LA: English
ER: M (Marine)
AB: The measure of trace element concentrations in entire organisms including digestive content instead of purged organisms is often responsible of an overestimation. The importance of the error depends upon the level of metals in the digestive content which is determined by the nature of its constituents and then vary with the feeding-habits of animals. The highest overestimations are observed for Pb and Cd in benthic-feeding worms and fishes, for Cu in benthic-feeding and plankton-feeding fishes.
AN: 1549306
37 of 369
TI: Benthic metabolism in a natural coastal petroleum seep.
AU: Montagna,-P.A.; Bauer,-J.E.; Prieto,-M.C.; Hardin,-D.; Spies,-R.B.
AF: Univ. Texas at Austin, Mar. Sci. Inst., Port Aransas, TX 78373, USA
SO: MAR.-ECOL.-PROG.-SER.. 1986. vol. 34, no. 1-2, pp. 31-40
NT: Incl. 32 ref.
LA: English
ER: M (Marine)
AB: The rates of 3 processes known to be mediated by microbial metabolic activity were measured in the sediments of a shallow-water (18 m depth) natural petroleum seep and a nearby non-seep area near Santa Barbara, California. Measurements of oxygen flux, hydrocarbon degradation, and sulfate reduction were made in the sediments of 3 stations with varying amounts of petroleum seepage. Total oxygen flux was not statistically different among the 3 stations studied. Rates of sulfate reduction and hydrocarbon degradation were greater at seep than non-seep sites. Within the seep area, greater rates of sulfate reduction and hydrocarbon degradation were found at the station of moderate seepage than at the margin of active oil and gas seepage. The greater rates of metabolism at the seep correlate with previous findings of higher amounts of ATP and macroinfauna at the seep. It is hypothesized that the higher abundances of infauna and concentrations of ATP at the seep are sustained by heterotrophic bacterial degradation of petroleum and the consumption of those bacteria by infauna.
AN: 1548931
38 of 369
TI: Reduction of selenate to selenide by sulfate-respiring bacteria: Experiments with cell suspensions and estuarine sediments.
AU: Zehr,-J.P.; Oremland,-R.S.
AF: U.S. Geol. Surv., Middlebrook Rd., Menlo Park, CA 94025, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1987. vol. 53, no. 6, pp. 1365-1369
LA: English
ER: B (Brackish)
AB: Washed cell suspensions of Desulfovibrio desulfuricans subsp. aestuarii were capable of reducing nanomolar levels of selenate to selenide as well as sulfate to sulfide. Reduction of these species was inhibited by 1 mM selenate or tungstate. The addition of 1 mM sulfate decreased the reduction of selenate and enhanced the reduction of sulfate. Increasing concentrations of sulfate inhibited rates of selenate reduction but enhanced sulfate reduction rats. The results indicate that sulfate is an inhibitor of the reduction of trace quantities of selenate. Therefore, direct reduction of traces of selenate to selenide by sulfate-respiring bacteria in natural environments is constrained by the ambient concentration of sulfate ions. The significance of this observation with regard to the role sediments play in sequestering selenium is discussed.
AN: 1540712
39 of 369
TI: Element cycling in wetlands: Interactions with physical mass transport.
AU: Hemond,-H.F.; Army,-T.P.; Nuttle,-W.K.; Chen,-D.G.
AF: Dep. Civ. Eng., Massachusetts Inst. Technol., Cambridge, MA 02139, USA
CO: 109. Meeting of the American Chemical Society, Chicago, IL (USA), 8-13 Sep 1985
SO: SOURCES-AND-FATES-OF-AQUATIC-POLLUTANTS. Hites,-R.A.;Eisenreich,-S.J.-eds. 1987. no. 216 pp. 519-540
ST: ADV.-CHEM.-SER. no. 216
LA: English
ER: F (Freshwater)
AB: In peatlands and other waterlogged ecosystems, a severely restricted physical transport regime may be regarded as a ratecontrolling factor for many biogeochemical processes. Transport in the liquid phase by advection, diffusion, and dispersion, and vapor-phase transport by ebullition and desaturation are the abiotic transport processes in wetland sediment. Biotic transport may also occur. Quantitative formulations for several of these transport processes exist, and specific, quantitative, useful examples of transport-oriented biogeochemical cycles are presented for two wetland ecosystems, namely, Belle Isle marsh and Thoreau's Bog.
AN: 1540691
40 of 369
TI: Molybdenum content in sea water and seaweeds from Saurashtra coast.
AU: Kesava-Rao,-C.
AF: Baddavanipeta, Urlam-532 425, Srikakulam (Dt.), A.P., India
SO: MAHASAGAR. 1986. vol. 19, no. 4, pp. 265-270
LA: English
ER: M (Marine)
AB: Molybdenum content has been estimated in sea water and 27 marine algal species. The ranges of Mo in sea water and seaweeds was found to be 9.86-10.87 mu g multiplied by kg super(-1) and 0.08-1.01 mg multiplied by kg super(-1) dry wt. respectively. Molybdenum to salinity ratios (Mo:S ppt) in sea water are in the range of 0.280-0.305. The observed differences in Mo:S ppt is attributed to the biological utlisation of Mo. Its narrow range of distribution in sea water and in seaweeds presumably indicate the relatively less biogeochemical reactivity of this micronutrient in marine environment. The three green algae Caulerpa scalpelliformis. Ulva lactuca and Codium dwarkense investigated do not show any definite trend in the bioaccumulation of Mo with their age.
AN: 1529490
41 of 369
TI: Chemical composition and mineralization of organic nitrogen in marine sediment.
OT: Kaitei taisekibutsu ni okeru yuki chisso kagobutsu no keitai to sono bunkai katei
AU: Koike,-I.
AF: Ocean Res. Inst., Univ. Tokyo, Minamidai 1, Nakano, Tokyo 164, Japan
CO: Symp. on Biological Activities and Biogeochemical Cycles in Marine Sediments, Tokyo (Japan), 8 Apr 1985
SO: UMI-MER. 1986. vol. 24, no. 2, pp. 104-110
LA: Japanese
ER: M (Marine)
AB: Amino acid nitrogen is a major component of the identified forms of nitrogen in coastal surface sediments, occupying up to two-thirds of total nitrogen in these sediments. Amounts of organic nitrogen in the interstitial waters of Tokyo Bay sediments were a minor fraction of the total nitrogen (ca. 1% in the surface), and this percentage decreased drastically with depth. Total amino acids in the surface sediments occupied ca. 50% of total interstitial organic nitrogen and 40% of the amino acids were free amino acids.
AN: 1524782
42 of 369
TI: Microbial interactions in marine sediments.
OT: Kaitei taisekibutsu-chu deno yukibutsu bunkai katei ni okeru biseibutsu-kan no sogosayo, tokuni ryusan-kangen-saikin o chushin to shite
AU: Shiba,-T.
AF: Otsuchi Mar. Res. Cent., Ocean Res. Inst., Univ. Tokyo, Akahama, Otsuchi, Iwate 028-11, Japan
CO: Symp. on Biological Activities and Biogeochemical Cycles in Marine Sediments, Tokyo (Japan), 8 Apr 1985
SO: UMI-MER. 1986. vol. 24, no. 2, pp. 97-103
LA: Japanese
ER: M (Marine)
AB: Interaction between fermentative and sulfate-reducing bacteria is discussed. Sulfate-reducing bacteria are present in the oxidized surface layer of marine sediments. Anaerobic biological processes take place within reduced micro-environments in the sediment. Interspecies transfer of fermentation products stimulates the growth of fermentative and sulfate-reducing bacteria. Such micro-environments influence the syntrophic growth of fermentative and sulfate-reducing bacteria.
AN: 1524771
43 of 369
TI: Geochemical studies of the degradation processes of organic matter in the sediments from coastal area.
OT: Naiwan taisekibutsu-chu ni okeru yukibutsu no bunkai ni kansuru chikyu-kagakuteki kenkyu
AU: Matsunaga,-K.
AF: Water Res. Inst., Nagoya Univ., Furocho, Chikusa, Nagoya 464, Japan
CO: Symp. on Biological Activities and Biogeochemical Cycles in Marine Sediments, Tokyo (Japan), 8 Apr 1985
SO: UMI-MER. 1986. vol. 24, no. 2, pp. 89-96
LA: Japanese
ER: M (Marine)
AB: Sedimentary core samples were collected from Hiuchi Nada, and Ise and Mikawa bays (Japan), where local eutrophication leads to increase of primary production in each bay. Sedimentation rates for Hiuchi Nada, and Ise and Mikawa bays were found to lie in the range of 0.13-0.21, 0.14-0.97 and 0.22 g/cm super(2)/yr, respectively, by the 210-Pb method. Vertical profiles of organic matter in these sediments were analyzed. Pseudo-degradation rate constants of organic C and N had ranges of 2.3-5.2 and 2.3-5.3 x 10 super(-2)/yr, respectively. The degradation rates of organic matter in the sediments were also calculated and are discussed in relation to primary production.
AN: 1524764
44 of 369
TI: Several phenomena in the benthic boundary layer of the Seto Inland Sea.
OT: Taisekibutsu kyokaimen o meguru shomondai. Seto-naikai
AU: Kawana,-K.; Hoshika,-A.; Tanimoto,-T.
AF: Gov. Ind. Res. Inst., Chugoku, Hiromachi 15000, Kure 737-01, Japan
CO: Symp. on Biological Activities and Biogeochemical Cycles in Marine Sediments, Tokyo (Japan), 8 Apr 1985
SO: UMI-MER. 1986. vol. 24, no. 2, pp. 81-99
LA: Japanese
ER: M (Marine)
AB: Detailed investigations on vertical and horizontal distributions of water quality (dissolved oxygen, nutrients, suspended matter, etc.) and their seasonal variation were carried out in the Seto Inland Sea. In summer, total suspended matter (TSM) concentration near the bottom was significantly influenced by water movement and turbid bottom water was observed in all areas with silty bottom sediments. Also in summer, oxygen-deficient bottom water was observed in regions of limited water movement and it contained large amounts of nutrients derived from bottom sediments.
AN: 1524757
45 of 369
TI: Oxygen profile in deep-sea calcareous sediment calculated on the basis of measured respiration rates of deep-sea meiobenthos and its relevance to manganese diagenesis.
OT: Shinkai-san meiobentosu no kokyu-ryo no sokutei kekka ni motozuite keisansareta shinkai sekkaishitsu taisekibutsu-chu no sanso bunpu to sono mangan no zokusei tono kankei
AU: Shirayama,-Y.; Swinbanks,-D.D.
AF: Ocean Res. Inst., Univ. Tokyo, Minamidai 1, Nakano, Tokyo 164, Japan
CO: Symp. on Biological Activities and Biogeochemical Cycles in Marine Sediments, Tokyo (Japan), 8 Apr 1985
SO: UMI-MER. 1986. vol. 24, no. 2, pp. 75-80
LA: English
ER: M (Marine)
AB: The respiration rate of deep-sea meiobenthos was measured using a gradient stoppered-diver technique, and the vertical profile of dissolved oxygen concentration in the sediment was calculated on the basis of the respiration rate using a steady-state model. At stations where the vertical profile of MnO sub(2) content showed a distinct peak in the subsurface 20 to 30 m layer of the sediment, oxygen penetrated to significant depths in the sediment. However, at stations where an MnO sub(2) peak was seen in the top few centimeters of the sediment, oxygen was completely consumed by benthic organisms within the 0-1 cm layer. This result supports the idea that manganese diagenesis within calcareous sediment is mainly regulated by biological processes through the respiratory activities of benthic organisms.
AN: 1524739
46 of 369
TI: A model of the effects of an infaunal xenophyophore on super(210)Pb distribution in deep-sea sediment.
OT: Naizaisei zenofaiofoa ga shinkai taisekibutsu-chu no namari 210 no bunpu ni oyobosu eikyo ni kansuru moderu
AU: Swinbanks,-D.D.; Shirayama,-Y.
AF: Ocean Res. Inst., Univ. Tokyo, Minamidai 1, Nakano, Tokyo 164, Japan
CO: Symp. on Biological Activities and Biogeochemical Cycles in Marine Sediments, Tokyo (Japan), 8 Apr 1985
SO: UMI-MER. 1986. vol. 24, no. 2, pp. 69-74
LA: English
ER: M (Marine)
AB: An earlier study showed that the infaunal xenophyophore Occultammina profunda , collected from a box-core of sediment from the Izu-Ogasawara Trench (sample depth 8260 m), contains high levels of the natural radionuclide super(210)Pb (450-500 dpm/g dry) in both its protoplasmic body (granellare) and waste products (stercomes). It was suggested that, through the excretion of stercomes rich in super(210)Pb, O. profunda may significantly affect the vertical distribution of super(210)Pb in the sediment. The theory and assumptions behind the model of stercome excretion are described.
AN: 1524725
47 of 369
TI: Effects of benthos on coastal sediments.
OT: Engan taisekibutsu ni taisuru teiseiseibutsukoka
AU: Matsumoto,-E.
AF: Geol. Surv. Japan, Yatabe, Ibaragi 305, Japan
CO: Symp. on Biological Activities and Biogeochemical Cycles in Marine Sediments, Tokyo (Japan), 8 Apr 1985
SO: UMI-MER. 1986. vol. 24, no. 2, pp. 64-68
LA: Japanese
ER: M (Marine)
AB: Benthos disturb coastal sediments, and enhance the flux of nutrients across the sediment-water interface. Bioturbation is quantified using natural radio-nuclide profiles in the sediment. Calculated diffusive fluxes of nutrients at the interface are often less than those measured in situ by the chamber method.
AN: 1524720
48 of 369
TI: Accumulation of Th, Pb, U, and Ra in marine phytoplankton and its geochemical significance.
AU: Fisher,-N.S.; Teyssie,-J.-L.; Krishnaswami,-S.; Baskaran,-M.
AF: Oceanogr. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: LIMNOL.-OCEANOGR. 1987. vol. 32, no. 1, pp. 131-142
LA: English
ER: M (Marine)
AB: The bioaccumulation of U, Th, Ra, and Pb in four diverse nanoplanktonic algal species and a picoplanktonic blue-green alga was determined with radiotracers. Among the nanoplankton, differences of 1-2 orders of magnitude in volume/volume concentration factors (VCFs) were observed for a given nuclide, but larger differences were observed among the four nuclides, with VCF values of Th > Pb > Ra approximately equals U. The picoplankton cells, with greater surface: volume ratios, had significantly higher VCF values. The mean VCF values in the nanoplankton of Th and Pb were 1.5 x 10 super(5) and 3.6 x 10 super(4) in the light and 2.8 x 10 super(5) and 7.3 x 10 super(4) in the dark.
AN: 1523104
49 of 369
TI: Organic carbon in the water column and its sedimentation, Fladen Ground (North Sea), May 1983.
AU: Cadee,-G.C.
AF: Netherlands Inst. Sea Res., P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: NETH.-J.-SEA-RES. 1986. vol. 20, no. 4, pp. 347-358
LA: English
ER: M (Marine)
AB: POC, DOC and sedimentation were studied during the spring phytoplankton bloom from April 27 to May 25. POC in the euphotic layer consisted largely of phytoplankton, maximum values of 0.5 mg/dm super(-3) were found at the height of a bloom of the colonial microflagellate Corymbellus aureus . DOC increased during the waxing of this C. aureus bloom to a maximum of 2.4 mg/dm super(-3) after the bloom. Data indicate that most of the primary produced material ended up in the DOC pool. Sedimentation accounted only for small losses from the euphotic zone: ca 1% of the daily primary produced material sank out, except at the end of the C. aureus bloom when values increased to almost 10%.
AN: 1523043
50 of 369
TI: Aerobic uptake of Fe(III)-precipitated phosphorus by microorganisms.
AU: Fleischer,-S.
AF: Inst. Limnol., Box 65, D-22100 Lund, Sweden
SO: ARCH.-HYDROBIOL. 1986. vol. 107, no. 2, pp. 269-277
LA: English
AB: Phosphorus co-precipitated with Fe(III) was microbially released in mixed and pure cultures as well as in intact sediment-water systems. The precipitated P was labelled and the original P in microorganisms was left unlabelled in order to trace the P transfer. The microorganisms released P from the precipitate under aerobic conditions while the FE(III) gel was solubilized and probably underwent peptidization. P removed from the precipitate was to a large extent kept in the microorganisms as these later released P under anaerobic conditions. The results show that biotic exchange processes are far more important in phosphorus dynamics than previously thought.
AN: 1503101
51 of 369
TI: Processes controlling movement, storage and export of phosphorus in a fen peatland.
AU: Richardson,-C.J.; Marshall,-P.E.
AF: Sch. For. and Environ. Stud., Duke Univ., Durham, NC 27706, USA
SO: ECOL.-MONOGR. 1986. vol. 56, no. 4, pp. 279-302
LA: English
ER: F (Freshwater)
AB: Collectively, the authors' field research and microcosm studies on the Houghton Lake fen suggest that soil adsorption and peat accumulation (i.e., phosphorus stored in organic matter) control long-term phosphate sequestration. But microorganisms and small sediments control initial uptake rates, especially during periods of low nutrient concentration and standing surface water. Carex P uptake increases later in the growing season during field fertilization, but algal populations in the fen water respond quickly and absorb significant amounts of P in areas where sewage effluent has been added. Both biotic and abiotic control mechanisms are thus functional in the peatland, and proportional effect of each on P transfers is dependent on water levels, the amount of available P, fluctuating microorganism populations, seasonal changes in P absorption by macrophytes, and P soil adsorption capacity.
AN: 1497463
52 of 369
TI: Seasonal study of uptake and regeneration of nitrogen on the Scotian Shelf.
AU: Cochlan,-W.P.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, B.C. V6T 1W5, Canada
SO: CONT.-SHELF-RES. 1986. vol. 5, no. 5, pp. 555-577
LA: English
ER: M (Marine)
AB: Nitrate and ammonium uptake and regeneration rates were measured in the euphotic zone of the Scotian Shelf during three cruises (spring, summer and late winter). Nitrate, as a portion of the total nitrogen assimilated (NO super(-)@)d3 uptake/total (NO super(-)@)d3 + NH super(+)@)d4) uptake), decreased with increasing ambient NH super(+)@)d4 concentration and depth. A large portion of phytoplankton growth was supported by "regenerated" production (NH super(+)@)d4) during spring and summer. In winter, growth was supported primarily by "new" production since NO super(-)@)d3 uptake represented 67% of the total nitrogen uptake during that period. In all seasons the phytoplankton showed a consistent preference for NH super(+)@)d4 utilization relative to NO super(-)@)d3, despite the abundance of NO super(-)@)d3 at times. In 21 of 23 measurements, NH super(+)@)d4 remineralization exceeded uptake, suggesting that phytoplankton nitrogen requirements were met or exceeded by in situ NH super(+)@)d4 regeneration. Remineralization rates covaried with both productivity ( super(14)C) and NH super(+)@)d4 uptake rates within the euphotic zone. These relationships were most apparent during the summer when nitrogen and carbon fluxes and algal biomass (Chl a) were greatest. The experimental approach used in this study demonstrates a seasonal pattern of NH super(+)@)d4 and NO super(-)@)d3 utilization previously unreported for Scotian Shelf waters.
AN: 1486593
53 of 369
TI: Studies on the mangrove ecosystem of the Jiulongjiang River estuary in China. 3. Accumulation and biological cycle of calcium and magnesium in Kandelia candel community.
AU: Lin,-P.; Chen,-R.-H.
AF: Dep. Biol., Xiamen Univ., Xiamen, People's Rep. China
SO: ACTA-OCEANOL.-SIN.-HAIYANG-XUEBAO. 1986. vol. 5, no. 3, pp. 447-455
LA: English
ER: B (Brackish)
AB: The accumulation and biological cycle of calcium and magnesium elements of the artificial 20-year old Kandelia candel community in the Jiulongjiang River estuary of Fujian Province, China were studied. Measured quantities of the two elements in the standing crop were (kg multiplied by ha super(-1)) 772.91 for Ca and 526.57 for Mg. In the biological cycle of the two-elements, the annual uptakes were 174.86 for Ca and 89.30 for Mg (kg multiplied by ha super(-1)); the amounts of Ca and Mg returned via litter-fall were estimated to be (kg multiplied by ha super(-1) multiplied by a super(-1)) 103.28 for Ca and 40.42 for Mg; annual retention was (kg multiplied by ha super(-1) multiplied by a super(-1)) 71.58 for Ca and 48.88 for Mg, respectively. The turnover periods of Ca and Mg are 8 and 13 years, respectively.
AN: 1468386
54 of 369
TI: Do continental shelves export organic matter?.
AU: Rowe,-G.T.; Smith,-S.; Falkowski,-P.; Whitledge,-T.; Theroux,-R.; Phoel,-W.; Ducklow,-H.
AF: Oceanogr. Sci. Div., Dep. Appl. Sci., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: NATURE. 1986. vol. 324, no. 6097, pp. 559-560
LA: English
ER: M (Marine)
AB: The authors summarize the shelf-edge exchange processes (SEEP) experiment, designed to test the export hypothesis. The absence of a positive imbalance in the organic carbon budget, reinforced by modest sediment deposition and biomass on the continental slope, led to rejection of the concept. Only a small fraction of continental shelf phytodetritus is exported; that not consumed in the spring is for the most part used on the continental shelf during the ensuing stratified season. The original hypothesis failed to recognize the contribution of pelagic microbial consumption and the lag in coupling between seasonal production and consumption processes.
AN: 1468272
55 of 369
TI: Seasonal deposition of phytodetritus to the deep-sea floor.
AU: Rice,-A.L.; Billett,-D.S.M.; Fry,-J.; John,-A.W.G.; Lampitt,-R.S.; Mantoura,-R.F.C.; Morris,-R.J.
AF: Inst. Oceanogr. Sci., Brook Rd., Wormley, Godalming, Surrey GU8 5UB, UK
CO: Symposium on the Oceanography of the Rockall Channel, Edinburgh (UK), 27-29 Mar 1985
SO: THE-OCEANOGRAPHY-OF-THE-ROCKALL-CHANNEL. Mauchline,-J.-ed. 1986. vol. 88 pp. 265-279
ST: PROC.-R.-SOC.-EDINB.,-SECT.-B. vol. 88
LA: English
AB: This paper summarises the results of the Porcupine Seabight studies over the past five years or so, using time-lapse sea-bed photography and microscopic, microbiological and chemical analyses of samples of phytodetritus and of the underlying sediment. The data are to some extent equivocal, but they suggest that the seasonal deposition is a regular and dramatic phenomenon and that the material undergoes relatively little degradation during its passage through the water column. The mechanisms leading to the aggregation of the phytodetritus have not been identified, and it is not yet known whether the phenomenon is geographically widespread nor whether it is significance to the deep-living mid-water and benthic communities.
AN: 1468121
56 of 369
TI: Lipid composition of the pelagic crab Pleuroncodes planipes, its feces, and sinking particulate organic matter in the Equatorial North Pacific Ocean.
AU: Wakeham,-S.G.; Canuel,-E.A.
SO: ORG.-GEOCHEM. 1986. vol. 9, no. 6, pp. 331-343
LA: English
ER: M (Marine)
AN: 1462369
57 of 369
TI: Early chlorin diagenesis in a Recent aquatic sediment.
AU: Keely,-B.J.; Brereton,-R.G.
SO: ORG.-GEOCHEM. 1986. vol. 10, no. 4-6, pp. 975-980
LA: English
ER: M (Marine)
AN: 1462299
58 of 369
TI: Biogeochemical processes of incorporation, transformation and migration of organic matter at the marine water-sediment interface: Simulation by 14C labelled compounds.
AU: Buscail,-R.
SO: ORG.-GEOCHEM. 1986. vol. 10, no. 4-6, pp. 1091-1097
LA: English
ER: M (Marine)
AN: 1462272
59 of 369
TI: Microbially mediated processes in environmental chemistry (lake sediments as model systems).
AU: Hanselmann,-K.W.
AF: Inst. Pflanzenbiol. (Mikrobiol.), Univ. Zurich, Zollikerstr. 107, CH-8008 Zurich, Switzerland
SO: CHIMIA. 1986. vol. 40, no. 5, pp. 146-147
LA: English
ER: F (Freshwater)
AB: Microbes alter environmental conditions through their metabolic activities which leads to changes in chemical equilibria. Thus microbes affect indirectly chemical processes like precipitation and dissolution, adsorption and desorption, oxidation and reduction, protonation and dissociation. In this presentation the author will summarize his views on a few basic questions of environmental microbiology: Where do microbes live in sediments? How do they live where they are? What do they do to the environment? It should soon become clear to the reader that we feel the best approach to understanding biochemical processes in lake sediments must be through interdisciplinary studies involving microbiologists, chemists, and geologists.
AN: 1455076
60 of 369
TI: Prerequisites for the development of mass balance models of the biogeochemical cycle of mercury in the Mediterranean Sea.
AU: Osman,-M.M.
SO: CENTRO. 1985. vol. 1, no. 2, pp. 21-34
LA: English
ER: M (Marine)
AN: 1451300
61 of 369
TI: Importance of ice edge phytoplankton production in the Southern Ocean.
AU: Smith,-W.O.,Jr.; Nelson,-D.M.
AF: Bot. Dep., Univ. Tennessee, Knoxville, TN 37996, USA
SO: BIOSCIENCE. 1986. vol. 36, no. 4, pp. 251-257
LA: English
ER: M (Marine)
AB: In view of the potentially great biogenic production in marginal ice zones, the authors have recently begun to assess the role of ice edge phytoplankton blooms and their impact on the entire ecosystem of the Southern Ocean. The ice edge may play a major role in biogeochemical cycles of the Southern Ocean.
AN: 1447693
62 of 369
TI: Biogeochemical studies of long-lived radionuclides in marine environments.
AU: Noshkin,-V.E.; Wong,-K.M.; Eagle,-R.J.; Jokela,-T.A.
CA: Lawrence Livermore National Lab., Livermore, CA (USA)
SO: 1985. 11 pp
NT: NTIS Order No.: DE86010783/GAR.
LA: English
ER: M (Marine)
AB: Research results from several studies relevant to seabed disposal of radioactive wastes are briefly discussed. The studies include: (1) mobilization of plutonium from Enewetak and Bikini lagoon sediments to seawater; (2) concentrations of sup 90 Sr, sup 137 Cs,/sup 239 + 240/Pu, sup 241 Am, sup 207 Bi and sup 210 Pb- sup 210 Bi-sup 210 Po in fish from the Marshall Islands; and (3) plutonium in northeast Atlantic sediments.
AN: 1444373
63 of 369
TI: Water, an endangered ecosystem.
AU: Stumm,-W.
AF: Swiss Fed. Inst. Water Resour. and Pollut. Control, Duebendorf, Zuerich CH 8600, Switzerland
SO: AMBIO. 1986. vol. 15, no. 4, pp. 201-207
LA: English
AB: Water is the most important link in all biogeochemical cycles; it acts as a mobile solvent, catalyst and reagent. Human activities such as phosphorus mining, pollution and over-use have disrupted these cycles. Of special concern is the perturbation of water cycles through the pursuit of energy for human development. The author postulates that first and second generation water problems, i.e. localized pollution by sewage and industrial wastes and pollution by synthetic chemicals, while often severe, may be solved. The third generation problem, i.e. perturbation of biogeochemical cycles, may be more difficult to address.
AN: 1440361
64 of 369
TI: (Microbiological processes involved in production and destruction of organic matter in inland water bodies.).
OT: Mikrobilogicheskie protsessy produktsii i destruktsii organicheskogo veshchestva vo vnutrennikh vodoemakh
AU: Romanenko,-V.I.
SO: LENINGRAD-USSR-NAUKA 1985. 295 pp
NT: Incl. bibliogr.: 509 ref.
LA: Russian
ER: F (Freshwater)
AB: The first part of the book deals with abundance of bacteria in water and bottom sediments as related to the type of the water body and with general regularities of photosynthesis and organic matter destruction as revealed from laboratory experiments and field data. Special attention is paid to CO sub(2) assimilation by heterotrophic microorganisms. The last chapter summarizes the results of long-term standard observations in the Rybinsk Reservoir which have shown that long-term variations in the production and destruction of organic matter are governed by hydrometeorological events. The second part gives data on microflora in oligotrophic and eutrophic reservoirs.
AN: 1440167
65 of 369
TI: Biological activity of bottom sediments in some Antarctic areas and off Peruvian coast.
OT: Biologicheskaya aktivnost' donnykh osadkov v nekotorykh rajonakh Antarktiki i u beregov Peru
AU: Andreeva,-N.M.; Agatova,-A.I.
AF: VNIRO, Moscow, USSR
SO: OKEANOLOGIYA. 1985. vol. 25, no. 6, pp. 959-965
LA: Russian
ER: M (Marine)
AB: A study was made of the content of organic matter, proteins, carbohydrates and lipids in the upper bottom sediments and their interstitial water along the shelf and slope of the Lazarev Sea, in the eastern part of the Bransfield Strait, to the north of South Georgia I. and off the northern Peru. Protease activity (decomposition of proteins down to amino acids) and electron transport system activity (organic matter oxidation rate down to CO sub(2) and H sub(2)O) were measured to reveal biological activity of bottom sediments. In the Antarctic areas the time of protein and organic matter cycle is shown to be, on average, 2-3 orders lower than off Peru. Interstitial water is supposed to be responsible for organic matter cycle across water-precipitation-interstitial water interface.
AN: 1422346
66 of 369
TI: Dinitrogen production from nitrite by a Nitrosomonas isolate.
AU: Poth,-M.
AF: Pac. Southwest For. and Range Exp. Stn., U.S. Dep. Agric. For. Serv., Riverside, CA 92507, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1986. vol. 52, no. 4, pp. 957-959
LA: English
AB: A chemolithotrophic ammonium-oxidizing bacterium that was able to reduce super(15)NO sub(2) super(-) to super(15)N sub(2) (m/z 30) while oxidizing ammonium under conditions of oxygen stress was isolated from stream sediments. Energy was derived from ammonium oxidation, as evidence by growth, with CO sub(2) serving as the sole C source. The organism was a gram-negative, motile, short rod that failed to grow either aerobically or anaerobically in heterotroph media. The organism was identified as a Nitrosomonas) sp.
AN: 1414555
67 of 369
TI: The health of the oceans and the need for its monitoring.
AU: Kullenberg,-G.
AF: Inst. Phys. Oceanogr., Univ. Copenhagen, Haraldsgade 6, 2200 Copenhagen, Denmark
CO: 1. International Symposium on Integrated Global Ocean Monitoring, Tallin (USSR), 2-10 Oct 1983
SO: INTEGRATED-GLOBAL-OCEAN-MONITORING. Izrael,-Yu.A.-ed. 1986. vol. 7, no. 1 pp. 47-58
ST: ENVIRON.-MONIT.-ASSESS. vol. 7, no. 1
LA: English
ER: M (Marine)
AB: Information contained in the recent Review of the Health of the Oceans carried out by the UN Joint Group of Experts on Scientific Aspects of Marine Pollution (GESAMP) is used in formulating monitoring requirements together with different aims of monitoring defined within the framework of the International Council for the Exploration of the Sea (ICES). The development is largely based on the concept of an interfaceflux model, which defines zones of interaction between oceanic processes and human activities. This is supplemented by consideration of biogeochemical cycles which describe the cycling of substances and may help elucidate specially important processes and fluxes. A definition of specific monitoring needs is obtained. Consideration is given separately to a series of waste or contaminant categories: sewage, organochlorines, petroleum, metals and radionuclides.
AN: 1396328
68 of 369
TI: Thallium in marine plankton.
AU: Flegal,-A.R.; Settle,-D.M.; Patterson,-C.C.
AF: Univ. California, Inst. Mar. Sci., Santa Cruz, CA 95064, USA
SO: MAR.-BIOL. 1986. vol. 90, no. 4, pp. 501-503
LA: English
ER: M (Marine)
AB: Concentrations of thallium in phytoplankton (0.02 to 0.8 mu g g super(-1)), zooplankton (0.03 to 0.5 mu g g super(-1)) and ichthyoplankton (0.1 mu g g super(-1)) from the central Pacific were comparable (x@u- = 0.2 mu g g super(-1)), as were the atomic ratios of thallium to calcium ( similar to 3 x 10 super(-6)) and to potassium ( similar to 1 x 10 super(-6) in those organisms. These relatively constant ratios plus the biounlimited ocean profile of thallium, indicate that it is rapidly cycled through plankton in the same manner as potassium, its principal biogeochemical analogue. The higher atomic ratios of thallium to potassium in pelagic clays (6 x 10) super(-)6) and ferromanganese nodules (4 x 10 super(-3)) suggest that both biological transport processes and abiotic transport processes influence this trace element's oceanic cycle.
AN: 1379894
69 of 369
TI: Dissolved humic substances of the Amazon River system.
AU: Ertel,-J.R.; Hedges,-J.I.; Devol,-A.H.; Richey,-J.E.; de-Nazare-Goes-Ribeiro,-M.; Ribeiro,-G.
AF: Chem. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 4, pp. 739-754
LA: English
ER: F (Freshwater)
AB: Aquatic humic and fulvic acids from nine mainstem and seven major tributary sites in the Amazon River Basion are characterized by their elemental and lignin phenol compositions. Combined humic substances represent 60% of the riverine dissolved organic carbon (DOC), with fulvic to humic acid (FA:HA) ratios in the mainstem averaging 4.7 plus or minus 1.0. All dissolved humic and fulvic acids have clearly recognizable lignin components at levels (8 and 3% of the carbon) suggesting a predominantly allochthonous source. Lignin compositional characteristics are dominated by diagenetic transformations, which include preferential loss of methoxylated structural units and oxidative degradation of lignin side chains. Over most of the mainstem humic and fulvic acids behave conservatively. However, downstream of the Rio Negro confluence, humic acids appear to be selectively absorbed onto fine suspended particles. Approximately 25 and 40% of the total fluxes of lignin and of carbon are represented in the dissolved humic substances. The annual flux of dissolved, chemically recognizable lignin in the Amazon River at Obidos is calculated to be 1.2 x 10 super(11) g yr super(-1).
AN: 1359805
70 of 369
TI: Compositions and fluxes of particulate organic material in the Amazon River.
AU: Hedges,-J.I.; Clark,-W.A.; Quay,-P.D.; Richey,-J.E.; Devol,-A.H.; de-M.-Santos,-U.
AF: Sch. Oceanogr., WB-10, Univ. Washington, Seattle, WA 98195, USA
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 4, pp. 717-738
LA: English
ER: F (Freshwater)
AB: Lignin, elemental, and stable carbon isotope compositions are reported for local plants and for coarse (> 63 mu m) and fine (< 63 mu m) suspended particulate materials collected along a 1,950-km reach of the lower Amazon River during four contrasting stages of the 1982-1983 hydrograph. Fluxes of chemically recognizable lignin in the two size classes generally parallel each other along the mainstem with the fine fraction usually predominating. Particulate organic matter transported in the coarse size fraction of the mainstem and its major tributaries is composed of recently formed and well preserved tree leaf debris along with some wood. Particulate organic matter in both size fractions is introduced largely from upstream sources within the Rio Solimoes and Rio Madeira drainage basins. Most of this organic matter is unreactive and is transported conservatively with mineral particles along the Amazon mainstem. However, some downstream compositional trends are seen in both size fractions which reflect the addition or exchange of highly degraded, super(13)C-depleted, and lignin-poor organic materials from lower basin sources.
AN: 1359403
71 of 369
TI: Hydrodynamic control of phytoplankton in low salinity waters of the James River estuary, Virginia, U.S.A.
AU: Filardo,-M.J.; Dunstan,-W.M.
AF: Old Dominion Univ., Dep. Oceanogr., Norfolk, VA 23508, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1985. vol. 21, no. 5, pp. 653-667
LA: English
ER: B (Brackish)
AB: Autotrophic biomass and productivity as well as nutrient distributions and phytoplankton cell populations in the James River Estuary, Virginia, were quantified both spatially and temporally over a 17-month period. Emphasis was placed on the very low salinity region of the estuary in order to gain informantion on the fate of freshwater phytoplankters. Differing amounts of freshwater plant biomass are advected into the estuary as living material, DOC or POC and the demonstrated variablility of this input must play an important role in marine biogeochemical cycling. An inverse relationship exists between the phytoplankton abundance in very low salinity waters and the abundance of biomass measured in the lower portion of the river (estuary). Thus, autotrophic production in the fresh and very low salinity areas may indirectly regulate the onset of the spring bloom in the estuary by controlling the amount of nutrients available.
AN: 1358720
72 of 369
TI: The estuarine interaction of nutrients, organics, and metals: A case study in the Delaware Estuary.
AU: Sharp,-J.H.; Pennock,-J.R.; Church,-T.M.; Tramontano,-J.M.; Cifuentes,-L.A.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE, USA
CO: 7. Bienn. Conf. of the Estuarine Research Federation, Virginia Beach, VA (USA), 23 Oct 1983
SO: THE-ESTUARY-AS-A-FILTER. Kennedy,-V.S.-ed. 1984. pp. 241-258
NT: Incl. 23 ref.
LA: English
ER: B (Brackish)
AB: In the estuarine environment, biogeochemical processes alter concentrations of soluble nutrients, organic matter, and trace metals. Some constituents show geochemical reactivity and are filtered out by "flocculation" type reactions; these may be considered as a geochemical "filter". Other constituents show biochemical reactivity and are filtered out by organismic processes; these may be considered as a biochemical "filter". Through use of data from the Delaware Estuary, the geochemical filter is illustrated as it affects humic acids, phosphate, and iron; the biochemical filter as it affects ammonium, phosphate, silicate, and urea. Contrasting examples are presented for the transition elements copper and nickel which show little filtration, despite the potential for bioreactivity. Cadmium and phosphate are used to illustrate a combined biogeochemical filter.
AN: 1334299
73 of 369
TI: The estuary as a filter: An introduction.
AU: Schubel,-J.R.; Kennedy,-V.S.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11790, USA
CO: 7. Bienn. Conf. of the Estuarine Research Federation, Virginia Beach, VA (USA), 23 Oct 1983
SO: THE-ESTUARY-AS-A-FILTER. Kennedy,-V.S.-ed. 1984. pp. 1-11
LA: English
ER: B (Brackish)
AB: An account is given of estuaries and their role as a filter, considering estuarine circulation, geological and geochemical procedures, biological and biochemical procedures and management.
AN: 1334047
74 of 369
TI: The Estuary as a Filter.
AU: Kennedy,-V.S.-(ed.)
AF: Biol. Dep., St. Francis Xavier Univ., Antigonish, N.S., Canada
CO: 7. Bienn. Conf. of the Estuarine Research Federation, Virginia Beach, VA (USA), 23 Oct. 1983
SO: ORLANDO,-FL-USA-ACADEMIC-PRESS 1984. 511 pp
LA: English
ER: B (Brackish)
AN: 1334013
75 of 369
TI: Biomass, community structure, and metabolic activity of the microbiota in benthic marine sediments and sponge spicule mats.
AU: White,-D.C.; Smith,-G.A.; Stanton,-G.R.
AF: Dep. Biol. Sci., Florida State Univ., Tallahassee, FL 32306, USA
SO: ANTARCT.-J.-U.S. 1985. vol. 19, no. 5, pp. 125-126
NT: Special issue: 1984 Review.
LA: English
ER: M (Marine)
AB: Application of quantitative chemical measures of biomass and community structure to the microbiota (prokaryotes and microeukaryotes) of near-shore marine sediments and sponge spicule mats in McMurdo Sound at Cape Armitage yielded 4 distinctive microbial communities with a biomass equivalent to a subtropical Florida estuary and low metabolic activity. Sediment cores and sponge spicule mats were recovered by divers from 3 areas: an anchor ice area (14 m under the ice), a nonspicule mat area (18 m under the ice), the sponge spicule mat area (22 m under the ice), and the subspicule mat sediment. The spicule mat was approximately equals 10 cm thick in this area. The subspicule mat sediments were characterized by low proportions of diatom "signature" fatty acids. The nonspicule mat sediments showed decreased proportions of sulfate reducing bacterial "signatures" possibly reflecting the relatively high level of sedimentary bioturbation.
AN: 1331524
76 of 369
TI: DOC dynamics in a Mediterranean seagrass system.
AU: Velimirov,-B.
AF: Univ. Wien, Inst. Zool., Abt. Meeresbiol., Althanst. 14, 1090 Vienna, Austria
SO: MAR.-ECOL.-PROG.-SER.. 1986. vol. 28, no. 1-2, pp. 21-41
NT: Incl. 71 ref.
LA: English
ER: M (Marine)
AB: In a study on energy flow in a Posidonia oceanica system, an attempt was made to explain the marked seasonal variations in DOC, POM and bacteria concentrations in the water above and within a seagrass meadow at the Island of Ischia (Lacco Ameno) off the Gulf of Naples (Italy). There was no correlation between seasonal variations of the 3 parameters within and between stations from shallow to deep. DOC concentrations showed distinct peaks for nearly every sampling period and ranged from 0.4 to 31.4 mgl super(-1). Although similar variations could be recorded for bacteria over the year, densities remained below 1.2 x 10 super(5) cells ml super(-1). Variations in the concentration of POM over the seasons were less obvious than for DOC and bacteria; concentrations ranged from 3.5 to 30 mg AFDW l super(-1). Weighted average concentrations of DOC, bacteria and POM in 1 m super(3) water representative for the water body above the P. oceanica) bed showed that bacterial contribution to the overall POM standing stock is insignificant.
AN: 1323050
77 of 369
TI: Transport of Carbon and Minerals in Major World Rivers. Part 2.
AU: Degens,-E.T.; Kempe,-S.; Soliman,-H.-(eds.)
CA: ICSU Sci. Comm. Problems Environ., Paris (France)
Hamburg (FRG)
CO: SCOPE-UNEP Workshop on "Transport of Carbon and Minerals in Major World Rivers", Assiut (Egypt), 26 Feb 1983
SO: MITT.-GEOL.-PALAEONTOL.-INST.-UNIV.-HAMB. HAMBURG-FRG-SELBSTVERL.-GEOLOGISCH-PALAEONTOLOGISCHES-INST.-UNIV. 1983. no. 55, 551 pp
NT: Published as: SCOPE/UNEP Sonderband.
LA: English
ER: F (Freshwater)
AB: The SCOPE-UNEP international program of studies on biogeochemical cycles presents the proceedings of a workshop on transport of carbon and minerals in major world rivers, held at Assiut, Egypt in 1983. The workshop proceedings (part II) comprises 41 papers dealing with various aspects of world river carbon and mineral chemistry, including freshwater ecology. A great number of side aspects, concerning mineral and carbon chemistry of rivers are included as well, such as e.g. carbon balance and forest ecosystems, eutrophication of coastal regions, monitoring by satellites, or nitrogenous organic matter transported by the major world rivers.
AN: 1318291
78 of 369
TI: Transport of Carbon and Minerals in Major World Rivers. Part 3.
AU: Degens,-E.T.; Kempe,-S.; Herrera,-R.-(eds.)
CA: ICSU Sci. Comm. Problems Environ., Paris (France)
UNEP, Hamburg (FRG)
CO: SCOPE-UNEP Workshop on "Transport of Carbon and Minerals in Major World Rivers", Caracas (Venezuela), 25 Mar 1984
SO: MITT.-GEOL.-PALAEONTOL.-INST.-UNIV.-HAMB. HAMBURG-FRG-SELBSTVERL.-GEOLOGISCH-PALAEONTOLOGISCHES-INST.-UNIV. 1985. no. 58, 661 pp
NT: Published as: SCOPE/UNEP Sonderband.
LA: English
ER: F (Freshwater)
AB: The SCOPE-UNEP international program of studies on biogeochemical cycles presents the proceedings of a workshop on transport of carbon and minerals in major world rivers, held at Caracas, Venezuela in 1984. The workshop proceedings (part III) comprises 51 papers dealing with all aspects of freshwater ecology and chemistry, related to carbon and mineral transport of major world rivers, including methodological papers on remote sensing, data acquisition and processing as well as water chemistry of the major world rivers.
AN: 1318274
79 of 369
TI: Report of the FAO/UNEP/WHO/IOC/IAEA Meeting on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena, Italy, 27-31 August 1984.
CA: FAO, Rome (Italy)
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27-31 Aug 1984
SO: FAO-FISH.-REP. 1985. no. 325, 17 pp
NT: ISBN 92-5-102242-9; 29 ref.
RN: FAO FIRI/R325 (FIRIR325)
LA: English
ER: M (Marine)
AB: The report presents data concerning the distribution, behavior and fate of mercury in the Mediterranean. Emphasis is placed upon those factors which make mercury different from other trace metals in biogeochemical cycles. Sources and budget calculations, levels in the Mediterranean, and selected processes in the Mediterranean are examined.
AN: 1317092
80 of 369
TI: Metabolism in interfacing zones between the watersheds and lakes: Effects on eutrophication.
AU: Wetzel,-R.G.
AF: W.K. Kellogg Biol. Stn., Michigan State Univ., Hickory Corners, MI 49060, USA
CO: Shiga Conf. '84 on Conservation and Management of World Lake Environment. Proceedings, Otsu (Japan), 27 Aug 1984
SO: SHIGA-CONFERENCE-'-84-ON-CONSERVATION-AND-MANAGEMENT-OF-WORLD-LAKE-ENVIRONMENT. Shiga-Prefectural-Gov.,-Otsu-Japan;-National-Inst.-for-Res.-Adv.-Japan 1985. pp. 133-138
LA: English
ER: F (Freshwater)
AB: A discussion is presented on the control of eutrophication, examining the biogeochemical cycling of nutrients and phytoplankton production and natural inter facing buffering systems which may be used as control measures. Vegetative cover on terrestrial drainage basins, economics of reducing external loadings of nutrients and interfacing zones between land and water are considered.
AN: 1316233
81 of 369
TI: Vertical flux and biogeochemical turnover regulate nutrient limitation of net organic production in the North Pacific Gyre.
AU: Smith,-S.V.; Kimmerer,-W.J.; Walsh,-T.W.
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 1, pp. 161-167
LA: English
ER: M (Marine)
AB: Water samples collected at a station in the North Pacific Gyre near Hawaii precisely define the temporal average vertical profile of dissolved inorganic and organic N and P (DON and DOP). DON and DOP concentrations decrease with depth. As shown by other studies, the regression of NO sub(3) super(-) (with or without NH sub(4) super(+)) vs. PO sub(4) super(3) super(-) yields an approximately Redfield slope and a negative nitrogen intercept. If DON and DOP are included in the regression equation, the intercept approaches 0. Vertical flux ratios of dissolved materials are calculated with a one-dimensional diffusion model. Downward mixing of DON offsets about 6% of the upward NO sub(3) super(-) flux; downward DOP mixing offsets only about 4% of the upward PO sub(4) super(3) super(-) flux. Net production of particulate organic matter in the euphotic zone is N limited because of slow biochemical turnover of dissolved organic N relative to that of dissolved organic P and to downward mixing.
AN: 1247404
82 of 369
TI: The interaction of trace metal radionuclides with humic substances.
AU: Musani-Marazovic,-L.; Faguet,-D.; Konrad,-Z.
AF: Cent. Mar. Res. Zagreb, "Rudjer Boskovic" Inst., Zagreb, Yugoslavia
CO: 189. Meeting of the American Chemical Society, Miami Beach, FL (USA), 28 Apr-3 May, 1985
SO: ORGANIC-MARINE-GEOCHEMISTRY. Sohn,-M.L.-ed. American-Chemical-Soc.,-Washington,-DC-USA.-Div.-Geochemistry 1986. no. 305 pp. 389-414
ST: ACS-SYMP.-SER. no. 305
LA: English
ER: M (Marine)
AB: The fate of trace metal radionuclides in the aquatic environment and their participation in the biogeochemical cycle depend strongly on the chemical and physicochemical form in which radionuclides are introduced natural waters. The abundance of natural humic substances and their ability to form metal complexes and to adsorb on suspended matter and sediment makes these substances especially important in transport, availability and accumulation of trace metal radionuclides in natural water environments. In that sense complexation of di- and tri-valent metal radionuclides with humic and fulvic acids of different origin was studied.
AN: 1247129
83 of 369
TI: Uptake and release of nitrogen compounds in coral reef and seagrass, Thalassia hemprichii (Ehrenb.) Aschers., bed sediments at Lizard Island, Queensland.
AU: Boon,-P.I.
AF: Dep. Bot., Monash Univ., Clayton, Vic. 3168, Australia
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1986. vol. 37, no. 1, pp. 11-19
LA: English
ER: M (Marine)
AB: The interstitial water in sediments from coral reef areas and seagrass (T. hemprichii ) beds at Lizard Island contained 6-48 mu mol l super(-1) ammonium, 4-7 mu mol l super(-1) nitrate plus nitrite, and 1 multiplied by 5-2 multiplied by 5 mu mol l super(-1) soluble reactive phosphorus. Concentrations of total dissolved primary amines were an order of magnitude higher in sediments from seagrass beds (about 140 mu mol l super(-1)) than from coral reef areas (about 10 mu mol l super(-1)). Ammonium-nitrogen was produced at rates of 0 multiplied by 7, 6, and 10 nmol g super(-1) h super(-1) in sediments from a bare beach, reef flat and seagrass bed, respectively. Added glycine and nitrate were also rapidly metabolized by microbes in the sediment (3 to > 5 nmol g super(-1) h super(-1)).
AN: 1247115
84 of 369
TI: Biogeochemical cycling of sulfur: Thiols in coastal marine sediments.
AU: Mopper,-K.; Taylor,-B.F.
AF: Div. Mar. and Atmos. Chem., Rosenstiel Sch. Mar. and Atmos. Sci., Univ. Miami, Miami, FL 33149-1098, USA
CO: 189. Meeting of the American Chemical Society, Miami Beach, FL (USA), 28 Apr-3 May, 1985
SO: ORGANIC-MARINE-GEOCHEMISTRY. Sohn,-M.L.-ed. American-Chemical-Soc.,-Washington,-DC-USA.-Div.-of-Geochemistry 1986. no. 305 pp. 324-339
ST: ACS-SYMP.-SER. no. 305
LA: English
ER: M (Marine)
AB: Thiols are major intermediates in the microbial cycling of sulfur and, because of their high reactivity, they may also play important roles in geochemical processes. Preliminary studies using a new, highly sensitive HPLC assay revealed that thiols are present at concentrations up to 100 mu M in intertidal marine sediments from Biscayne Bay (FL). Methanethiol (MeS) and 3-mercaptopropionate (MP) were the major thiols found. The presence of the latter compound suggests that, in addition to protein degradation, anaerobic decomposition of dimethylpropiothetin (DMPT), a major sulfur compound of marine algae and higher plants, may be an important source of thiols and a significant degradation pathway for DMPT in the environment.
AN: 1247000
85 of 369
TI: Biogenic fluxes of carbon and oxygen in the ocean.
AU: Platt,-T.; Harrison,-W.G.
AF: Mar. Ecol. Lab., Bedford Inst. Oceanogr., P.O. Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
SO: NATURE. 1985. vol. 318, no. 6041, pp. 55-58
LA: English
ER: M (Marine)
AB: Rates of oxygen utilization (OUR) at depth in the ocean have been interpreted as showing that rates of carbon fixation by phytoplankton, as estimated by super(14)CO sub(2) assimilation in vitro, must be in error. The oxygen is consumed in the decomposition of organic matter sinking from the photic zone: there is a stoichiometrically equivalent flux of nitrate from the deep water towards the surface. For comparison with the super(14)C data, it is conventional to extrapolate OUR to total equivalent phytoplankton production through a constant factor f, the ratio of nitrate-based production (P sub(new)) to total production (P sub(t)) as define by Dugdale and Goering. The authors show here that f is variable in space and time for most provinces of the ocean. Furthermore, they show that in nitrogen-limited systems, such as the pelagic of the open ocean, P sub(t) and f should be positively correlated. Applying these results to data from the Sargasso Sea, they find that the carbon fluxes estimated by super(14)C assimilation are consistent with the oxygen fluxes estimated by OUR.
AN: 1241084
86 of 369
TI: In situ particle generation in a southern Swedish stream.
AU: Parker,-C.
AF: Address not stated
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 2, pp. 432-437
LA: English
ER: F (Freshwater)
AB: An increase in the number of particles was measured below a waterfall in a sourthern Swedish stream. POC increased below the falls by 0.12 mg C liter super(-1), 5% of the total POC present. DOC decreased by 0.1 mg C liter super(-1) but was not significant and inorganic content remained unchanged. The number of Celloscope-measured particles in the size range of 2-20 mu m increased below the falls, with a 66% increase in particles of 4-6- mu m diameter. Although POC generation was small it was greater than published allochthonous input rates to streams. Abiotic particle generation, although extremely difficult to measure, may be far more important to carbon dynamics in stream ecosystems than previously thought.
AN: 1236427
87 of 369
TI: Loss and uptake of super(15)N-ammonium in submerged soils of a cattail marsh.
AU: Dean,-J.V.; Biesboer,-D.D.
AF: Dep. Agron., Univ. Illinois, Urbana, IL 61801, USA
SO: AM.-J.-BOT. 1985. vol. 72, no. 8, pp. 1197-1203
LA: English
ER: F (Freshwater)
AB: The uptake, distribution, and recovery of nitrogen by field populations of T. latifolia L. (cattails) were determined using ( super(15)NH sub(4)) sub(2)SO sub(4). The results show that 75.3% (53.6% in the plant and 21.7% in the soil) of the isotopically labeled nitrogen added to sampling cylinders containing a single cattail plant could be recovered at the end of one growing season, whereas only 34.6% could be recovered from control cylinders. The increased recovery of super(15)NH sub(4) super(+)-nitrogen in cylinders containing actively growing T. latifolia) compared to cylinders not containing plants suggests that T. latifolia rapidly assimilates labeled nitrogen before it is lost via denitrification or uptake by free-living soil microorganisms. Measurements of redox potentials in a 60-cm-deep field core planted or not planted with T. latifolia showed that only the top 2 and 5 cm of the water column was oxidized (greater than 200 mv at pH 7), respectively. The remaining 58 and 55 cm of the column, including the soil water interface, was reduced (less than 200 mv at pH 7).
AN: 1236407
88 of 369
TI: Metabolic activities in flocculent surface sediments and underlying sandy littoral sediments.
AU: Sweerts,-J.P.; Rudd,-J.W.M.; Kelly,-C.A.
AF: Limnol. Inst., Rijkstraatweg 6, 3631 AC Nieuwersluis, Netherlands
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 2, pp. 330-338
LA: English
ER: F (Freshwater)
AB: Parts of the sandy littoral sediment of a Precambrian shield lake (Lake 302S) were intermittently covered with a layer of flocculent organic-rich material 1-20 mm thick. Sandy sediments with flocculent surface sediment had higher rates of respiration (31-105%) and photosynthesis (37-224%) than those without. Densities of invertebrate macrofauna were 10 time shigher in the flocculent surface sediment than in the underlying sandy sediment, accounting for 17 vs. 5% of the total respiration. Microprofiles of oxygen concentration showed that almost all of the dissolved oxygen in the overlying water was consumed as it diffused through 5-7 mm of the flocculent surface sediment. The presence of flocculent surface sediment also decreased the depth of penetration of sulfate into the sandy sediment.
AN: 1236394
89 of 369
TI: Characterization of native bacteria and their utilization of algal extracellular products by a mixed-substrate kinetic model.
AU: Jensen,-L.M.
AF: Int. Agency for super(14)C Determination, 11 Agern Alle, DK-2970 Hoersholm, Denmark
SO: OIKOS. 1985. vol. 45, no. 3, pp. 311-320
LA: English
ER: F (Freshwater)
AB: Assimilation and mineralization of super(14)C labelled extracellular products (EOC) by native bacterial populations were followed in a diel study and from early spring through autumn in two eutrophic Danish lakes. Kinetic analyses according to a mixed-substrate kinetic model always revealed linear kinetics. The method was found useful in unveiling in situ specific algal-bacterial associations mediated through the release of EOC from the primary producers. Further, bacterial adaptation toward the phycosphere of Microcystis aeruginosa could be detected by following the shift in X-intercepts for the lines of net uptake and respiration during the development of a bloom of M. aeruginosa . By simultaneous measurements of particulate primary production, EOC release and transport of EOC to the bacteria by a differential filtration technique, it is shown that the method presented does not generally estimate changes in the kinetic parameters, but does reveal qualitative changes. It is concluded that the mixed-substrate method is a powerful approach for elucidating specific algal-bacterial associations in situ, even in highly complex eutrophic environments.
AN: 1231707
90 of 369
TI: Mass transfer to and from small particles in the sea.
AU: Csanady,-G.T.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 2, pp. 237-248
LA: English
AB: Slowly sinking particles exchange mass with their liquid environment if dissolution processes within the particles maintain a surface concentration excess or deficiency chi sub(0) of a soluble substance above background. If the exchange is controlled by diffusion in the liquid phase, the total mass loss is proportional to chi sub(0), diffusivity D, and particle diameter d. If advection associated with the sinking of the particle dominates over diffusion, the exchange rate varies as chi sub(0)D super(2/3)d super(2) and is weakly affected by particle density and fluid viscosity. This is the case for spherical particles of a diameter greater than or approximate to 70 mu m. The resulting dissolution rate per unit depth of sinking is constant for large particles, but increases sharply once the particles are small and slow enough for mass exchange to be controlled by diffusion.
AN: 1231401
91 of 369
TI: Extracellular organic carbon (EOC) released by phytoplankton and bacterial production.
AU: Soendergaard,-M.; Riemann,-B.; Joergensen,-N.O.G.
AF: Bot. Inst., Univ. Aarhus, Nordlandsvej 68, DK-8240 Risskov, Denmark
SO: OIKOS. 1985. vol. 45, no. 3, pp. 323-332
LA: English
ER: F (Freshwater)
AB: Parts of the pelagic carbon cycle were investigated during ten diel cycles in five Danish lakes and one coastal area. The gross release of EOC ranged from 5 to 46% of the diel primary production and the major part of the released products were assimilated by bacteria. It was shown that diel time-course incubations should be used as opposed to short-time incubations. An analysis based on primary production and amino acid assimilation in the freshwater samples showed that the FDC-method tended to overestimate the bacterial production, whereas the thymidine-method probably represents the true order of magnitude with a trend toward underestimation. In the lakes the assimilation of EOC contributed substantially (> 80%) to the bacterial production in three cases, moderately (38-50%) in three cases and of less (< 38%) importance in one case.
AN: 1231319
92 of 369
TI: Accumulation of minerals and trace elements in biogenic mucus at hydrothermal vents.
AU: Juniper,-S.K.; Thompson,-J.A.J.; Calvert,-S.E.
AF: IFREMER, Cent. Brest, B.P. 337, 29273 Brest Cedex, France
SO: DEEP-SEA-RES. 1986. vol. 33, no. 3A, pp. 339-347
LA: English
ER: M (Marine)
AB: Several mechanisms have been found by which a hydrothermal vent organism enhances metal and metalloid deposition at vent sites. Mucus accumulations associated with an alvinellid polychaete worm at northeast Pacific vents were found to be usually rich in elemental sulfur, sulfide minerals and trace elements. Mucus production by the worm may be a mechanism for both internal and external detoxification of accumulating metals. Analyses indicate that inorganic components accumulate in the mucus through secretion or precipitation of elemental sulfur, occlusion of mineral particles, and adsorption and complexation of soluble species by the organic matrix of the mucus. Mucus-aggregated minerals contribute to the mass of sulfide deposits forming at these vents, but their quantitative significance is not clear.
AN: 1231208
93 of 369
TI: Reconciling measured and predicted fluxes of oxygen across the deep sea sediment-water interface.
AU: Reimers,-C.E.; Smith,-K.L.,Jr.
AF: Scripps Inst. Oceanogr., Univ. California, San Diego, La Jolla, CA 92093, USA
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 2, pp. 305-318
LA: English
ER: M (Marine)
AB: Rates of sediment community oxygen consumption determined in situ are compared to fluxes predicted from oxygen microelectrode gradients measured in cores from similar to 3,750-m water depth in the eastern North Pacific. Oxygen concentrations decrease exponentially over > 1.5 cm and suggest that organic matter in the sediments is degraded most rapidly immediately below the sediment-water interface. Molecular diffusion of oxygen across the interface is modeled as an "internal regime" and can account for nearly all the directly measured in situ flux, 0.20 plus or minus 0.02 mu mol cm super(-2) d super(-1). Millimeter depth-scale profiles of porosity, organic C, carbonate c, and bacteria abundance are reported to provide additional constraints on interface processes, including the relative effects of organic matter degradation and bioturbation.
AN: 1231118
94 of 369
TI: Microorganisms in deep-sea hydrothermal plumes.
AU: Winn,-C.D.; Karl,-D.M.; Massoth,-G.J.
AF: Hawaii Inst. Geophys., Dep. Oceanogr., Univ. Hawaii, Honolulu, HI 96822, USA
SO: NATURE. 1986. vol. 320, no. 6064, pp. 744-746
LA: English
ER: M (Marine)
AB: The study of hydrothermal vents at oceanic spreading centres has led to a re-evaluation of some basic tenets concerning energy flux through oceanic ecosystems and the sources and sinks for dissolved ions in sea water. Hydrothermal vents vary considerably, from relatively low-temperature (< 25 degree C) fluid discharges to the spectacular high-temperature ( similar to 350 degree C) black smokers. The authors report the presence of elevated bacterial biomass in a hydrothermal plume originating from the Juan de Fuca Ridge, and discuss the potential geochemical significance of these microorganisms.
AN: 1230989
95 of 369
TI: Biogeochemical factors influencing the residence time of microconstituents in a large tidal estuary, Delaware Bay.
AU: Church,-T.M.
AF: Coll. Mar. Stud., Univ. Delaware, Newark, DE 19716, USA
CO: 8. International Symposium on the Chemistry of the Mediterranean, Primosten (Yugoslavia), May 1984
SO: 8th-INTERNATIONAL-SYMPOSIUM-ON-THE-CHEMISTRY-OF-THE-MEDITERRANEAN,-PRIMOSTEN,-YUGOSLAVIA,-MAY,-1984. Branica,-M.-ed. 1986. vol. 18, no. 2-4 pp. 393-406
ST: MAR.-CHEM. vol. 18, no. 2-4
LA: English
ER: M (Marine)
AB: Evidence is drawn from the Delaware estuary to illustrate biogeochemical estuarine reaction processes using salinity distribution data and mass balance calculations. The Delaware retains some of its estuarine trace elements as sedimented estuarine particles, while others are more conservative and largely exported. Those retained by sedimenting processes include trace elements in primarily geochemical (particle reactive) chemistries, while those exported appear recycled by biochemical (nutrient reactive) chemistries. Often, the behavior of trace elements (e.g., Fe, Cd) and nutrients (e.g., PO sub(4)) appear biogeochemically linked. Other examples are drawn from mixing studies to illustrate particle interaction, and benthic flux measurements to illustrate limited diagenetic reflux.
AN: 1230895
96 of 369
TI: Deep-sea biological activity: In situ biochemical transformation of organic matter labelled with carbon-14 at the water sediment interface at 2,000 m depth in the Bay of Biscay.
OT: Activite biologique en domaine profond: Transformations biochimiques in situ de composes organiques marques au carbone-14 a l'inte rface eau-sediment par 2,000 m de profondeur dans le golfe de Gascogne
AU: Cahet,-G.; Sibuet,-M.
AF: Univ. Pierre et Marie Curie, Lab. Arago, F-66650 Banyuls sur mer, France
SO: MAR.-BIOL. 1986. vol. 90, no. 2, pp. 307-315
LA: English
ER: M (Marine)
AB: In June 1983, in situ water-sediment interface experiments were conducted with the submersible Cyana at 2,000 m depth in the Bay of Biscay. Dissolved or particulate super(14)C-labelled organic compound was injected into a compartment of a box-corer specifically adapted for use with the submersible. After incubation, the biochemical reactions were stopped by addition of Formalin. In the laboratory, the pathways of the labelled molecules in the various extracts were followed by means of chemical and granulometric fractionation and isolation of meiofauna. Various experiments run at 1 atm and at in situ pressures, for incubation times of between 3 and 144 h, revealed in situ biochemical transformation. After recovery of the samples, activity at 1 atm was low, with only 4% of the radioactivity being recovered in the macromolecules against 84% for the in situ experiments. Results comprise new evidence of the existence of a rapid biochemical transformation at great depth in the ocean.
AN: 1230568
97 of 369
TI: Biogeochemical cycling of lignocellulosic carbon in marine and freshwater ecosystems: Relative contributions of procaryotes and eucaryotes.
AU: Benner,-R.; Moran,-M.A.; Hodson,-R.E.
AF: Dep. Microbiol., Univ. Georgia, Athens, GA 30602, USA
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 1, pp. 89-100
LA: English
ER: M (Marine); F (Freshwater)
AB: The relative contributions of procaryotes and eucaryotes to the degradation of the lignin and polysaccharide components of lignocellulosic detritus in two marine and two freshwater wetland ecosystems were determined. Two independent methods-physical separation of bacteria from fungi and other eucaryotes by size fractionation, and antibiotic treatments-were used to estimate procaryotic and eucaryotic contributions to the degradation of ( super(14)C-lignin)lignocelluloses and ( super(14)C-polysaccharide)lignocelluloses in samples of water and decaying plant material from each environment. Both methods yielded similar results. The results indicate a basic difference between the microbial degradation of lignocellulosic material in terrestrial and aquatic environments. Fungi have long been considered the predominant degraders of lignocellulose in terrestrial systems; the present results indicate that in aquatic systems bacteria are the predominant degraders of lignocellulose.
AN: 1199627
98 of 369
TI: Accumulation of some monoaromatic compounds during the degradation of crude oil by marine bacteria.
AU: Rontani,-J.F.; Bertrand,-J.-C.; Blanc,-F.; Giusti,-G.
AF: Cent. Oceanol. Marseille, U.R.A. 41, Fac. Sci. Luminy, 13288 Marseille Cedex 9, France
SO: MAR.-CHEM. 1986. vol. 18, no. 1, pp. 1-7
LA: English
ER: M (Marine)
AB: In continuous culture of a marine mixed bacterial population, the different fractions of crude petroleum strongly degraded. Analysis of the aromatic fraction by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) reveals the accumulation, during degradation, of some monoaromatic compounds probably initially trapped in asphaltenic structures.
AN: 1199306
99 of 369
TI: Comparison of the structures of humic acids from marine sediments and degraded field diatoms by super(13)C- and super(1)H-NMR spectroscopy.
AU: Poutanen,-E.-L.; Morris,-R.J.
AF: Inst. Mar. Res., P.O. Box 33, SF-00931 Helsinki, Finland
SO: MAR.-CHEM. 1985. vol. 17, no. 2, pp. 115-126
LA: English
ER: M (Marine)
AB: Humic acids isolated from marine sediments of the Peru continental shelf and from a degraded field diatom population dominated by the diatoms Skeletonema costatum, Nitzschia seviata and Thalassiosira sp. were characterized on the basis of infrared spectra and super(13)C- and proton-NMR spectra. Aliphatic structures were found to constitute the major fraction of humic acids and they appear to be highly branched. Carbohydrates and to a lesser extent aromatic materials, carbonyl-, ether-, alcohol- and amino groups are important contributors to the structure of marine humic acids. A close relationship was observed between the chemical structure of the sedimentary humic acid and the plankton humic acid.
AN: 1199278
100 of 369
TI: Comparison of the lipid composition of sediments from three sites in the Venezuela Basin.
AU: Shaw,-P.M.; Johns,-R.B.
AF: Dep. Org. Geochem., Univ. Melbourne, Parkville, Vic. 3052, Australia
SO: MAR.-GEOL. 1985. vol. 68, no. 1-4, pp. 205-216
LA: English
ER: M (Marine)
AB: Solvent extractable and bound lipids from pelagic (site 1), turbidite (site 2) and hemipelagic (site 3) sediments of the Venezuela Basin have been analysed to indicate input sources of sedimentary lipids. Acids consist mainly of normal, branched, monoenoic and cyclopropyl components less than 24 carbons long with concentration and distribution indicating bacterial inputs of a similar level to each site. Long-chain acids, alcohols and 24-ethylcholest-5-en-3 beta -ol represent an input of higher plant-derived organics, which maximizes at sites 2 and 3. The source of this material is likely to be the Orinoco and Amazon river systems. Algal input is suggested by the distribution of sterols comprising diatoms and coccolithophores (24-methyl sterols), and dinoflagellates (dinosterol and other 4-methyl sterols).
AN: 1199189
101 of 369
TI: Wax esters and triacylglycerols in sinking particulate matter in the Peru upwelling area (15 degree S, 75 degree W).
AU: Wakeham,-S.G.
AF: Dep. Chem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: MAR.-CHEM. 1985. vol. 17, no. 3, pp. 213-235
LA: English
ER: M (Marine)
AB: The flux and composition of wax esters and triacylglycerols were measured in particulate matter collected by free-drifting sediment traps in the Peru upwelling area to assess diurnal variations in sources and vertical transport of these lipids. Traps were deployed for periods of 8-12 h during both day and night at the base of the euphotic zone (10-14 m) and at approximately equals 50 m. Although the flux of total particulate organic carbon varied 4x, the flux of wax esters varied by 84x and triacylglycerols by 30x. POC, was esters, and triacylglycerols also showed different temporal patterns. The highest wax ester flux was measured in shallow traps at night and is attributed to increased inputs from zooplankton which feed near the surface at night. Triacylglycerol flux was high in both shallow and deep nocturnal traps, consistent with inputs of both phytoplankton and zooplankton lipids.
AN: 1199115
102 of 369
TI: Depletion of super(13)C in Cretaceous marine organic matter: Source, diagenetic, or environmental signal?.
AU: Dean,-W.E.; Arthur,-M.A.; Claypool,-G.E.
AF: U.S. Geol. Surv., P.O. Box 25046, Federal Cent., Denver, CO 80225, USA
SO: MAR.-GEOL. 1986. vol. 70, no. 1-2, pp. 119-157
NT: Special issue: Deep ocean black shales.
LA: English
ER: M (Marine)
AN: 1199009
103 of 369
TI: The ecological and biogeochemical roles of the bacterioplankton in coastal marine ecosystems.
AU: Azam,-F.
AF: Scripps Inst. Oceanogr., La Jolla, CA 920939, USA
CO: U.S.-Pakistan Workshop on Marine Science in the Arabian Sea and Coastal Pakistan, Karachi (Pakistan), Nov 1982
SO: MARINE-GEOLOGY-AND-OCEANOGRAPHY-OF-ARABIAN-SEA-AND-COASTAL-PAKISTAN. Haq,-B.U.;Milliman,-J.D.-eds. National-Science-Found.,-Washington,-DC-USA 1984. pp. 317-326
NT: Incl. bibliogr.: 51 ref.
LA: English
ER: M (Marine)
AB: Bacterial abundance and growth are strongly correlated with phytoplankton biomass, suggesting a tight coupling between the production of organic matter by algae and its utilization by bacteria. The bacterioplankton are likely to be a major route for energy and material fluxes in marine foodwebs, consuming one-third or more of the primary production. Recent evidence suggests that heterotrophic flagellates consume a significant fraction of the bacterial production, though many other organisms also eat bacteria. This predation probably aids in nutrient recycling by releasing the nitrogen and phosphorus sequestered by the bacteria. Since bacteria account for about 80% of the living surface in seawater, they are also likely to be important in the absorption and transformation of dissolved pollutants. Therefore, it is clear that any study of coastal marine ecosystems should consider the role of the bacterioplankton. (Publ. in coop. with: Minist. Sci. and Technol. (Pakistan)).
AN: 1198970
104 of 369
TI: Biogeochemical cycle in marine systems.
AU: Hattori,-A.
AF: Ocean Res. Inst., Univ. Tokyo, Tokyo, Japan
CO: 20. Gen. Assem. International Council of Scientific Unions. ICSU Symp. on Global Change, Ottawa (Canada), 25 Sep 1984
SO: GLOBAL-CHANGE.-THE-PROCEEDINGS-OF-A-SYMPOSIUM-SPONSORED-BY-THE-INTERNATIONAL-COUNCIL-OF-SCIENTIFIC-UNIONS-ICSU-DURING-ITS-20TH-GENERAL-ASSEMBLY-IN-OTTAWA,-CANADA-ON-SEPTEMBER-25,-1984. Malone,-T.F.;Roederer,-J.G.-eds. ICSU,-Paris-France 1985. no. 5 pp. 278-286
ST: ICSU-PRESS-SYMP.-SER. no. 5
NT: Incl. bibliogr.: 33 ref.
LA: English
ER: M (Marine)
AB: Biogeochemical cycles in marine ecosystems are discussed with special reference to the behavior of nitrogen. Some research recommendations are presented which should be considered in the framework of the proposed International Geosphere and Biosphere Program (IGBP).
AN: 1198439
105 of 369
TI: The science of global change -- an overview.
AU: Friedman,-H.
AF: Natl. Res. Counc., 2101 Constitution Ave. NW, Washington, DC 20418, USA
CO: 20. Gen. Assem. International Council of Scientific Unions. ICSU Symp. on Global Change, Ottawa (Canada), 25 Sep 1984
SO: GLOBAL-CHANGE.-THE-PROCEEDINGS-OF-A-SYMPOSIUM-SPONSORED-BY-THE-INTERNATIONAL-COUNCIL-OF-SCIENTIFIC-UNIONS-ICSU-DURING-ITS-20TH-GENERAL-ASSEMBLY-IN-OTTAWA,-CANADA-ON-SEPTEMBER-25,-1984. Malone,-T.F.;Roederer,-J.G.-eds. ICSU,-Paris-France 1985. no. 5 pp. 20-52
ST: ICSU-PRESS-SYMP.-SER. no. 5
LA: English
ER: B (Brackish)
AB: Various areas of interdisciplinary research in the Sun-Earth system are discussed in detail: 1) sun and climate; 2) oceans and atmosphere; 3) the interannual variability of the tropical ocean and the global atmosphere (TOGA); 4) ocean and atmosphere chemistry and biogeochemical cycles; 5) the hydrological cycle; 6) ozone chemistry and dynamics; 7) CO sub(2) and agriculture; 8) remote sensing of global metabolism; 9) lithospheric processes; 10) sun and earth; 11) atmospherical catastrophes.
AN: 1198315
106 of 369
TI: The influence of microtopographic heterogeneity on carbon dioxide efflux from a subarctic bog.
AU: Luken,-J.O.; Billings,-W.D.
AF: Dep. Biol. Sci., Northern Kentucky Univ., Highland Heights, KY 41076, USA
SO: HOLARCT.-ECOL. 1985. vol. 8, no. 4, pp. 306-312
LA: English
ER: F (Freshwater)
AB: Soil carbon dioxide efflux was measured in hummock and hollow microhabitats of a subarctic peat bog near fairbanks, Alaska, during the 1983 growing season. Regardless of the presence of permafrost, hummocks showed a late June or early July peak in soil respiration followed by a gradual decrease. Hollows and wet Carex Lawns showed a gradual increase in soil respiration with no mid-season peaks. Regression equations using soil temperature and soil moisture as independent variables explained 76% of the variance associated with soil carbon dioxide efflux. Sucrose (100 g m super(-2)) applied to a field plot caused a significant increase in soil respiration but nitrogen (5 g m super(-2)) did not. Sequential effects of nitrogen and phosphorus on peat respiration were demonstrated in a laboratory experiment.
AN: 1192401
107 of 369
TI: Hydrocarbons in water and suspended matter from the Pacific Ocean and Bering Sea.
OT: Uglevodorody vody i vzvesi tikhogo okeana i Beringova morya
AU: Nemirovskaya,-I.A.
AF: Inst. Okeanol. AN S.S.S.R., Moscow, USSR
SO: OKEANOLOGIYA-OCEANOLOGY-MOSC.. 1985. vol. 25, no. 5, pp. 761-767
LA: Russian
ER: M (Marine)
AB: In surface water from the Tsugarustrait, Shatsky Rise and Bering Sea the concentration of organic compounds (mainly hydrocarbons) averaged 8 mu g/l, which is close to the background level in the Atlantic and Indian Oceans. In the Bering Sea the concentrations of dissolved and suspended particulate organic matter in surface water were 26 and 58 mu g/l respectively, in the near bottom layer the corresponding values were 42 and 52 mu g/l. The anomalously high (exceeding 50 mu g/l) concentrations of both forms in near bottom layers in some cases are assumed to be associated with intensive biochemical processes.
AN: 1192269
108 of 369
TI: A steady-state model for two humic fractions.
AU: Frisk,-T.; Pennanen,-V.
AF: Natl. Board Waters, Finland, P.O. Box 250, SF-00101 Helsinki, Finland
SO: VESIENTUTKIMUSLAIT.-JULK.,-HELSINKI-PUBL.-WATER-RES.-INST.,-HELSINKI. 1985. no. 65, pp. 98-107
LA: English
ER: F (Freshwater)
AB: A steady-state mass balance model for two humic fractions is presented. In the model the input of humus to the lake and the output from the lake, the loss reaction of humus including decay and sedimentation, and the possible transfer reactions between the two fractions are taken into account. The loss coefficients of the fractions are linearly interdependent. The absolute values of the coefficients cannot, however, be determined using the steady-state approach of this study. The characteristic coefficients of the interdependence of the coefficients as well as the loss coefficients of total humus were calculated for three lakes: Hakojaeryi, Kalaejaeryi, and Seinaejaeryi.
AN: 1174993
109 of 369
TI: Nutrient regeneration by zooplankton in southern Lake Huron.
AU: Korstad,-J.
AF: Dep. Nat. Sci., Oral Roberts Univ., 7777 S. Lewis, Tulsa, OK 74171, USA
SO: J.-GREAT-LAKES-RES. 1983. vol. 9, no. 3, pp. 374-388
LA: English
ER: F (Freshwater)
AB: Rates of nutrient regeneration by zooplankton ( mu mol/mg dry wt/hr) in southern Lake Huron from April to August 1975 ranged from undetectable to 2.6 for total phosphorus (TP), undetectable to 0.8 for total soluble phosphorus (TSP), undetectable to 0.12 for soluble reactive phosphorus (SRP), undetectable to 0.97 for ammonia (NH sub(3)), undetectable to 3.8 for nitrate plus nitrite (NO sub(3) + NO sub(2)), and undetectable to 2.9 for silica (SiO sub(2)). Two diel experiments were conducted. Times of highest rates of regeneration varied for the different nutrients on these dates. Using the average concentration of zooplankton in the surface waters during this study, the calculated average concentration of nutrients regenerated by zooplankton was 0.012 mu mol P/L/hr for TP, 0.0046 mu mol P/L/hr for TSP, 0.0016 mu mol P/L/hr for SRP, 0.0146 mu mol N/L/hr for NH sub(3), 0.043 mu mol N/L/hr for NO sub(3) + NO sub(2), and 0.058 mu mol Si/L/hr for SiO sub(2). The contribution of nutrient regeneration by zooplankton to the turnover time of the various nutrients in the surface waters was calculated to be 212 hr for TSP, 69 hr for SRP, 62 hr for NH sub(3), 505 hr for NO sub(3) + NO sub(2), and 531 hr for SiO sub(2).
AN: 1170937
110 of 369
TI: Sediments and sedimentation.
AU: Mothes,-G.; Proft,-G.
AF: Akad. Wiss. DDR, Inst. Geogr. und Geooekol., Ber. Hydrol., Jena, GDR
SO: LAKE-STECHLIN:-A-TEMPERATE-OLIGOTROPHIC-LAKE. Casper,-S.J.-ed. 1985. vol. 58 pp. 375-399
ST: MONOGR.-BIOL. vol. 58
LA: English
ER: F (Freshwater)
AB: This contribution summarizes the findings on sediments and the sediment process in the Lake Stechlin area, and compares them with other regions, discussing open questions.
AN: 1169898
111 of 369
TI: The chemical environment.
AU: Mothes,-G.; Koschel,-R.; Proft,-G.
AF: Akad. Wiss. DDR, Inst. Geogr. und Geooekol., Ber. Hydrol., Jena, GDR
SO: LAKE-STECHLIN:-A-TEMPERATE-OLIGOTROPHIC-LAKE. Casper,-S.J.-ed. 1985. vol. 58 pp. 87-125
ST: MONOGR.-BIOL. vol. 58
LA: English
ER: F (Freshwater)
AB: Changes in the chemical features of Lake Stechlin, Nehmitz and Dagow as a result of the cooling water circuit of the nuclear power plant must be expected both spatially and temporally. In the following sections the authors will give basic data about the phosphorus, carbon, nitrogen, silicium and oxygen content of the water characterizing the chemical state of the lake system before and during the operation of the nuclear power plant. The results give an insight into the temporal and spatial concentration gradients, the long-term changes and the external loads of these elements (import and export). This is intended to contribute to a deeper understanding of the main features of lake metabolism, such as primary production, secondary production, microbial activities, and sedimentation which will be described in other chapters of this volume.
AN: 1169771
112 of 369
TI: Stable sulfur isotope ratios as a tool for interpreting ecosystem sulfur dynamics.
AU: Fuller,-R.D.; Mitchell,-M.J.; Krouse,-H.R.; Wyskowski,-B.J.; Driscoll,-C.T.
AF: Dep. Civ. Eng., Syracuse Univ., Syracuse, NY 13210, USA
SO: WATER-AIR-SOIL-POLLUT. 1986. vol. 28, no. 1-2, pp. 163-171
LA: English
ER: F (Freshwater)
AB: Stable isotope ratios ( delta super(34)S) were evaluated in soil solution leachates, soluble plus absorbed soil SO sub(4) super(2-), soil organic S, precipitation, and in stream solutions along an elevational gradient at the Hubbard Brook Experimental Forest in the White Mts. of New Hampshire, U.S.A. The delta super(34)S of soil organic S varied with soil horizon and vegetation type, but was generally more negative than adsorbed or soil solution SO sub(4) super(2-1). In the Bh horizon, delta super(34)S of organic S was typically more negative than the Oa horizon or lower mineral soil (Bs1). The patterns suggest a combination of plant and microbial fractionation processes. Stream delta super(34)S values decreased with decreasing elevation and were correlated with decreases in SO sub(4) super(2-1) concentration, suggesting an additional S source in higher elevation coniferous sites with a unique delta super(34)S.
AN: 1155855
113 of 369
TI: Nitrification, nitrate reduction, and nitrogen immobilization in a tidal freshwater marsh sediment.
AU: Bowden,-W.B.
AF: Yale Univ., Sch. For. and Environ. Stud., New Haven, CT 06511, USA
SO: ECOLOGY. 1986. vol. 67, no. 1, pp. 88-99
LA: English
ER: F (Freshwater)
AB: The dominant microbial transformations of ammonium and nitrate in the sediments of a tidal freshwater marsh were estimated from measured rates of isotope dilution of ammonium( super(15)N) added to sediment and litter samples, reduction of nitrate( super(15)N) to ammonium( super(15)) in fresh sediments, and net exchange of ammonium and nitrate between the marsh and river water in flumes built in the field. In two separate laboratory experiments, nitrification in mixed, fresh, surface sediments was 2.8 and 3.4 nmol multiplied by cm super(-3) multiplied by h super(-1). In undisturbed field sediments, nitrification rates are probably <1 nmol multiplied by cm super(-3) multiplied by h super(-1). Additions of nitrate( super(15N) to fresh sediments showed that nitrate produced from ammonium by nitrification was reduced very quickly. Less than 10% of this nitrate was reduced back to ammonium by dissimilation. The net transfer of nitrate in this marsh is to the sediments, and since nitrate does not accumulate in these sediments, the remaining nitrate produced by nitrification must be reduced by denitrification or by assimilatory nitrate reduction.
AN: 1153536
114 of 369
TI: Mineralization of organic carbon on and in the sediment of Lake Grevelingen.
AU: Londeboom,-H.J.; Klerk,-H.A.J.,de; Sandee,-A.J.J.
AF: North Sea Dir., Minist. Transp. and Public Works, P.O. Box 5807, 2280 HV Rijswijk, Netherlands
SO: NETH.-J.-SEA-RES. 1984. vol. 18, no. 3-4, pp. 492-510
LA: English
ER: B (Brackish)
AB: Within the framework of a research project on the carbon cycle in saline Lake Grevelingen a study of the mineralization on and in the sediment was made. The oxygen uptake by the sediment was measured using the bell jar method at 6 sampling stations. Applying a C over O sub(2) conversion factor of 0.29, it was calculated that 330 g multiplied by m super(-2) is mineralized in the sediment of the lake annually. By means of biomass estimates of the macroflora and fauna inside the bell jars and regression analysis, the contribution of these organisms to the carbon mineralization rate was calculated to be 70 and 95 g multiplied by m super(-2) multiplied by a super(-1), respectively. The effect of oxygen gradients and apparent diffusion coefficients up the oxygen uptake rate was studied with microelectrodes. This indicated that bioturbation is a major factor influencing the oxygen uptake rate. A good correlation between this rate and temperature was found.
AN: 1151993
115 of 369
TI: The carbon balance of a saline lake (Lake Grevelingen, The Netherlands).
AU: Vries,-I.,de
AF: Delft Hydraulics Lab., P.O. Box 177, 2600 MH Delft, Netherlands
SO: NETH.-J.-SEA-RES. 1984. vol. 18, no. 3-4, pp. 511-528
LA: English
ER: B (Brackish)
AB: An annual carbon balance is presented for Lake Grevelingen, a former shallow estuary in the SW part of The Netherlands. Planktonic primary production is the main source of organic material, with an estimated contribution of at least 60%. From a comparison of the carbon balance with oxygen consumption measurements, the efficiency of the planktonic auto- and microheterotrophic community in producing particulate organic material is estimated at 44%. The pelagic and benthic compartment of the lake are tightly coupled by the filtering activity of benthic macrofauna, causing a high grazing pressure on phytoplankton (estimated at 55% of net production) and a transport of suspended organic particles to the sediment by deposition of faeces and pseudofaeces, exceeding passive sinking with a factor 3 to 4.
AN: 1151633
116 of 369
TI: Carbon fixation and chlorophyll in bottom sediments of brackish Lake Grevelingen, The Netherlands.
AU: Nienhuis,-P.H.; de-Bree,-B.H.H.
AF: Delta Inst. Hydrobiol. Res., Vierst. 28, 4401 EA Yerseke, Netherlands
SO: NETH.-J.-SEA-RES. 1984. vol. 18, no. 3-4, pp. 337-359
LA: English
ER: B (Brackish)
AB: Lake Grevelingen in the SW Netherlands is a former estuary and since 1971 a brackishwater lake, connected with the North Sea by sluices. Chlorophyll a concentrations in the upper 10 cm (sliced per cm) of Lake Grevelingen sediments are given for the years 1977-1980. Chlorophyll a in the upper cm of the bottom varied between 20-400 mg multiplied by m super(-2). Average values in 1-3 m deep sandy and silty-sandy stations amounted to 67.5-82.2 mg multiplied by m super(-2) in the upper cm. A restricted number of phaeopigment data for 1977 revealed an average phaeopigment-chlorophyll a ratio of 0.03 (sand) to 0.39 (silt). POC measured in 1977 and 1978 in the top cm of the sediment showed annual average values ranging between 0.2 and 0.7% of sediment dry weight. super(14)C fixation data in the light, as measured in a laboratory incubator, are given for 1979 and 1980, with highest values during summer (200-500 mg C multiplied by m super(-2) multiplied by d super(-1)) and lower values in winter. Integrated annual values give average super(14)C fixation estimates per station, ranging between 47 g C multiplied by m super(-2) multiplied by a super(-1), with a variation coefficient of 35 to 49% of the mean. Average super(14)C dark fixation values varied between 13 and 27% of average hight fixation values.
AN: 1151579
117 of 369
TI: Sediment-water exchange in Lake Grevelingen under different environmental conditions.
AU: Kelderman,-P.
AF: Inst. Hydraulic and Environ. Eng., P.O. Box 3015, 2601 DA Delft, Netherlands
SO: NETH.-J.-SEA-RES. 1984. vol. 18, no. 3-4, pp. 286-311
LA: English
ER: B (Brackish)
AB: The impact of various environmental factors on the phosphate and silicate sediment-water exchange in Lake Grevelingen has been investigated in a series of laboratory experiments under aerobic conditions. Silicate mobilization from the sediment showed a strong temperature dependence, with fluxes ranging from 5 plus or minus 3.2 mg Si multiplied by m super(-2) multiplied by d super(-1) at 5 degree C to 85 plus or minus 18 mg Si multiplied by m super(-2) multiplied by d super(-1) at 20 degree C. Phosphate mobilization fluxes ranged from 0.5 plus or minus 0.7 mg PO sub(4)-P multiplied by m super(-2) multiplied by d super(-1) at 5 degree C to 11 plus or minus 3.4 mg P multiplied by m super(-2) multiplied by d super(-1) at 20 degree C. The phosphate exchange fluxes showed a significantly linear negative correlation with the phosphate concentrations in the overlying water, in accordance with Fick's first law of diffusion. Based on the results of 4 different sediment types, general relationships have been derived for the phosphate sediment-water exchange as a function of water temperature and phosphate concentration in Lake Grevelingen. The results have successfully been applied in a simulation model for the phosphate concentration in Lake Grevelingen for the years 1974-1977.
AN: 1151334
118 of 369
TI: A new method for the recovery of ammonium from natural waters for measurement of super(15)N composition in isotope dilution experiments.
AU: Fisher,-T.R.; Morrissey,-K.M.
AF: Univ. Maryland-CEES, Horn Point Environ. Lab., Cambridge, MD 21613, USA
SO: MAR.-CHEM. 1985. vol. 16, no. 1, pp. 11-21
LA: English
ER: M (Marine)
AB: Efforts to measure the rate of nitrogen recycling in natural waters have depended on estimates of ammonium production using the super(15)N isotope dilution method. This technique requires the removal of dissolved ammonium from the water sample for analysis of the super(15)N content. Steam distillation or micro-diffusion methods have been most commonly used, but these techniques are labor intensive and time consuming. The authors have attempted to simplify the measurement of the planktonic regeneration of ammonium by presenting a mercury precipitation technique which is simple, practical, and easily used at sea.
AN: 1134182
119 of 369
TI: Organic matter in sediments from the Bay of Cadiz and its salt-ponds areas.
OT: Materia organica en los sedimentos de la bahia de Cadiz y sus zonas de marismas y salinas
AU: Establier,-R.; Blasco,-J.; Gomez,-A.; Escolar,-D.
AF: Inst. Invest. Pesq., Puerto Pesquero s/n, Cadiz, Spain
SO: INVEST.-PESQ.-BARC.. 1984. vol. 48, no. 2, pp. 285-301
LA: Spanish
ER: M (Marine)
AB: Analysis of the concentrations of organic matter, phosphates and other complementary parameters in scdiments of 62 sampling stations from the Bay of Cadiz (Spain) and surrounding salt-pond areas showed enrichment of organic matter and phosphates in the surface. This may be partly attributed to urban effluents flowing in the area studied. The low values obtained in the carbon/nitrogen relation suggest that the incorporation of these materials in the sediments is produced by phytoplankton assimilation of nutrients, originating from the microbiological descomposition of the organic matter in the environment. The vertical trends of the sedimentary column at various stations showed intense bottom activity as well as marked sedimentary progression. Grain-size distribution of the sediments is a significant factor in the accumulation levels of the organic matter and phosphates in the different sectors of the study area.
AN: 1130624
120 of 369
TI: The isotopic mass balance of sulphur in oceanic sediments (the Pacific Ocean as an example).
AU: Lein,-A.Yu.
AF: Inst. Biochem. and Physiol. Microorg., U.S.S.R. Acad. Sci., Pushchino, Moscow 142292, USSR
SO: MAR.-CHEM. 1985. vol. 16, no. 3, pp. 249-257
LA: English
ER: M (Marine)
AB: Dissimilatory sulphate reduction is the main biogeochemical reaction responsible for the cycle of sulphur and its isotopic composition in modern oceanic sediments. The maximal intensity of this process, measured with the help of radioactive isotopes, is typical of sediments in the peripheral regions of the ocean to a depth of 1,000 m and makes up 10-60 mu g S/kg wet silt/day. The minimal enrichment with super(32)S of the buried, reduced sulphur and the maximal accumulation of heavy isotopes in sulphate sulphur of pore waters are observed under conditions of the most intensive biogeochemical processes. Further away from continents the intensity of bacterial sulphate reduction diminishes to a fraction of 1 mu g S/kg wet silt/day, and the reduced sulphur becomes enriched in super(32)S (up to - 50.0 ppt.). The amount of reduced sulphur in the total sulphur buried in modern sediments of the Pacific Ocean is twice the amount of sulphate sulphur.
AN: 1130548
121 of 369
TI: Cycling of transuranic radionuclides in the Columbia River, its estuary and the Northeast Pacific Ocean. Progress Report, January-December 1984.
AU: Beasley,-T.M.
CA: Oregon State Univ., Newport, OR (USA). Marine Science Cent
SO: 1984. 22 pp
NT: NTIS Order No.: DE85011485/GAR; Contr. AT06-77EV70030.
RN: DOE-EV-70030-13 (DOEEV7003013)
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: This report summarizes progress from 1 January 1984 to 31 December 1984 in research dealing with the behavior of transuranic and other long-lived radionuclides in the Columbia River downstream from the Hanford Reservation and in the northeast Pacific Ocean. Goals achieved include: The analysis of thirteen continental slope cores for sup 137 Cs,/sup 239, 240/Pu and sup 241 Am is complete; while sup 210 Pb, C, and P analyses continue. The analysis of composite river sediment samples for sup 63 Ni inventory in lower river reaches was done. Mass spectrometry analysis of fish, mussels, and plankton determined the isotopic composition of plutonium during 1962 to 1980.
AN: 1125226
122 of 369
TI: A tentative assessment of the balance of heavy and transition metals in the Caspian Sea.
OT: Predvaritel'naya otsenka balansa tyazhelykh i perekhodnykh metallov v Kaspijskom more
AU: Morozov,-N.P.; Petukhov,-S.A.
AF: VNIRO, Moscow, USSR
SO: METEOROL.-GIDROL. 1985. no. 9, pp. 75-81
LA: Russian
ER: M (Marine)
AB: The balance of Fe, Mn, Zn, Cu, Ni, Co, Cr, Pb and Cd in the Caspian Sea was analysed on the basis of field hydrological observations and literature data. 68-87% of Fe, Mn, Ni and Pb are shown to be discharged with eolian material. Rivers contribute the major proportion of Zn, Cu, and Cd (36-48%) in solution and of Mn, Pb, cd and Co (24, 26, 28 and 69% respectively) in suspension, Zn, Cu and Cd are added into the Sea with atmospheric precipitation (27, 12 and 14% respectively). 66 and 52% of Fe and Mn load were in particulate form. 98.2-99.9% of metals are buried in bottom sediments. The input from sewage constituted from 0.03 (Co) to 1.3-1.9% (Cd and Cu) which is 10 times lower than in the Baltic Sea.
AN: 1124601
123 of 369
TI: Hydrocarbons in marine sediments from eastern Taiwan.
AU: Jeng,-W.-L.
AF: Inst. Oceanogr., Natl. Taiwan Univ., Taipei, Taiwan
SO: ACTA-OCEANOGR.-TAIWAN. 1984. no. 15, pp. 31-38
LA: English
ER: M (Marine)
AB: Hydrocarbons in marine sediments taken from the continental margin of eastern Taiwan have been analyzed by gas chromatography. Total n-alkane contents in the sediments range from 21 to 1213 ng/g dry wt. with a mean of 307 ng/g dry wt.. Generally speaking, higher n-alkane levels were found in offshore sediments and lower n-alkane levels in near-shore sediments. Carbon preference indices for 42 samples range from 1.0 to 7.9 with an average of 2.4. This average is higher than those (2.0 and 1.7) found in Taiwan Strait sediments, suggesting larger inputs of land-derived organic matter from the Central Range and Coastal Range. In addition, the pentacyclic aromatic hydro-carbon perylene has been detected in offshore sediments (9-50 ng/g dry wt.) exclusively. An in situ formation rather than a deposition of perylene directly into the sediments is discussed.
AN: 1123650
124 of 369
TI: (Microbiological processes involved in carbon and nitrogen cycles in lakes.).
OT: Mikrobiologicheskie protsessy krugovorota ugleroda i azota v ozerakh
AU: Kuznetsov,-S.I.; Saralov,-A.I.; Nazina,-T.N.
SO: MOSKVA-USSR-NAUKA 1985. 213 pp
NT: Incl. bibliogr.: 720 ref.
LA: Russian
ER: F (Freshwater)
AN: 1121346
125 of 369
TI: A carbon budget for South West Arm, Port Hacking.
AU: Cuff,-W.R.; Sinclair,-R.E.; Parker,-R.R.; Tranter,-D.J.; Bulleid,-N.C.; Giles,-M.S.; Godfrey,-J.S.; et-al.
AF: Maritimes Forest Res. Cent., Can. For. Serv., P.O. Box 4000 Fredericton, N.B., E3B 5P7, Canada
SO: SYNTHESIS-AND-MODELLING-OF-INTERMITTENT-ESTUARIES.-A-CASE-STUDY-FROM-PLANNING-TO-EVALUATION. Cuff,-W.R.;Tomczak,-M.,Jr.-eds 1983. vol. 3 pp. 193-232
ST: LECT.-NOTES-COAST.-ESTUAR.-STUD. vol. 3
LA: English
ER: B (Brackish)
AB: A multidisciplinary study of the structure and dynamics of a small ( similar to 78 ha) Australian marine embayment (South West Arm of Port Hacking, New South Wales) was conducted during 1973-1978. Compatible data were obtained by studying processes in terms of the flow of carbon. The carbon budget developed in this paper represents an attempt at a synthesis of that information. The chemical and biological species contained in each of 10 compartments are described; as data allows, the average carbon mass within each compartment and the average flow rates between the compartments, with variances, are estimated. This information is used to piece together the distribution of carbon among the compartments and to ascertain the major flow paths of carbon into, within, and out of South West Arm.
AN: 1116394
126 of 369
TI: Regeneration rate and extent of phosphorus and silicon from decomposing phytoplankton assemblages.
AU: Kamatani,-A.; Ueno,-Y.
AF: Tokyo Univ. Fish., Konan, Minato-ku, Tokyo 108, Japan
SO: BULL.-JAP.-SOC.-SCI.-FISH.-NISSUISHI. 1980. vol. 46, no. 5, pp. 537-542
LA: Japanese
AB: A study of the aerobic decomposition of two different phytoplankton assemblages from Tokyo Bay was conducted under the thermostated-dark condition in an attempt to study the rate and extent of regeneration of phosphorus and silicon. In the first stage 70-80% of the biogenous-P regenerated and the remaining which was considered to be refractory and resistant, underwent slow biochemical oxidation in the second stage. Silica dissolution rate constant at the first stage was 0.5 - 8 x 10 super(-2) day super(-1), which was 10 to 30 times smaller than that for the acid-cleaned silica walls. The silica dissolution rate constant at the first stage increased about 2.3 times corresponding to a rise in temperature of 10 degree C and the activation energy was estimated to be about 14.1 kcal mol super(-1). The ratio of reactive Si to P increased exponentially as regeneration proceeded.
AN: 1111930
127 of 369
TI: The distribution of cadmium, copper, nickel, manganese, and aluminium in surface waters of the open Atlantic and European shelf area.
AU: Kremling,-K.
AF: Inst. Meereskunde, Duesternbrooker Weg 20, D-2300 Kiel, FRG
SO: DEEP-SEA-RES. 1985. vol. 32, no. 5A, pp. 531-555
LA: English
ER: M (Marine)
AB: A total of 232 surface water samples (6 m depth) was collected in the open Atlantic Ocean and in the Brazilian and northwest European shelf areas during three transects between 23 degree S and 59 degree N in October/November 1980, August/September 1981, and March/April 1982. The open Atlantic cadmium, copper, and nickel concentrations increase towards higher latitudes with averages (nmol kg super(-1) plus or minus 1 s) and ranges of 0.002 to 0.10 (0.040 plus or minus 0.026) Cd; 0.86 plus or minus 0.34 (1.28 plus or minus 0.26) Cu; and 1.88 plus or minus 0.66 (3.40 plus or minus 0.61) Ni in the regions 7 degree S to 35 degree N and 35 degree to 59 degree N, respectively. These elevations are probably the result of the biogeochemical cycles of these elements and of the hydrographical regimes in those regions. The manganese and aluminium distributions show a different geographical pattern with maximum concentrations in the region between around 10 degree N to 30 degree N which probably originate from aeolian input (Sahara dust).
AN: 1111119
128 of 369
TI: Biological principles of pond culture: Sediment and benthos.
AU: White,-D.
SO: PRINCIPLES-AND-PRACTICES-OF-POND-AQUACULTURE:-A-STATE-OF-THE-ART-REVIEW. Lannan,-J.E.;Smitherman,-R.O.;Tchobanoglous,-G.-eds. 1983. pp. 33-37
NT: Incl. bibliogr.: 38 ref. Grant No. AID/DSAN-G-0264.
LA: English
ER: F (Freshwater)
AB: The greatest contribution of benthic organisms to aquaculture is their ability to modify sediments and enhance release of nutrients. Where algae serve directly to provide a food source for fish, nutrient transfer may be immediate. Benthic bacteria and the large benthic invertebrates are most important in reworking soils and in facilitating release of nutrients from the soil by assimilating compounds and keeping the topo few centimeters in constant movement. Production of fish will be directly proportional to the fertility and type of soils present.
AN: 1110183
129 of 369
TI: Minipellets: A new and abundant size class of marine fecal pellets.
AU: Gowing,-M.M.; Silver,-M.W.
AF: Cent. Mar. Stud., Univ. California, Santa Cruz, CA 95064, USA
SO: J.-MAR.-RES. 1985. vol. 43, no. 2, pp. 395-418
LA: English
ER: M (Marine)
AB: Minipellets, fecal pellets from 3 to 50 mu m in diameter, were found on detritus collected by a particle interceptor trap array in the upper 2,000 m of the eastern tropical Pacific. The fluxes of minipellets reached 5 x 10 super(6) m super(-2)/day, and exceeded fluxes of larger (> 50 mu m diameter) fecal pellets by 3 orders of magnitude. Carbon flux of minipellets was 11-49% that of larger pellets; however, carbon flux of ultrastructurally intact cells (microalgae and bacteria) in minipellets was equal to that of intact cells in the larger pellets. Minipellets appear ubiquitous; the authors have found them in all their samples of particulates from other cruises from surface waters to bathypelagic depths. Minipellets are probably wastes of protozoans and small invertebrates that consume marine snow and larger fecal pellets throughout the water column, thereby maintaining the high numbers of minipellets from the surface to 2,000 m.
AN: 1094914
130 of 369
TI: Global Ocean Flux Study. Proceedings of a workshop held at Woods Hole, Massachusetts on September 10-14, 1984.
CA: National Research Counc., Washington, DC (USA)
CO: Global Ocean Flux Study, Woods Hole, MA (USA), 10-14 Sep 1984
SO: 1984. 378 pp
NT: NTIS Order No.: PB85-203800/GAR; Grant NSF-OCE84-17920.
LA: English
ER: M (Marine)
AB: A major goal for Ocean Sciences is to gain an understanding of the processes controlling marine biogeochemical cycling at regional, basin-wide, and global spatial scales, and at time scales from interannual through decadal. The physical, chemical, and biological processes governing the production and fate of biogenic materials in the sea need to be understood well enough to predict their influences on, and responses to, global-scale perturbations, whether natural or anthropogenic, since these perturbations can have a significant impact on human populations. To achieve this goal, a long-term multidisciplinary study of the flux of material through the global ocean environment is needed. (Sponsored by Off. Nav. Res., Arlington, VA., NASA, Washington, DC., and NOAA, Washington, DC).
AN: 1084571
131 of 369
TI: The contribution of bacterioplankton to productivity and organic matter cycle in the southeastern Pacific Ocean.
AU: Sorokin,-Yu.I.; Mamayeva,-T.I.
AF: South Dep., Shirshov Inst. Oceanol., USSR Acad. Sci., Gelendzhik, USSR
SO: DOKL.-EARTH-SCI.-SECT. 1985. vol. 275, no. 1-6, pp. 214-218
LA: English
ER: M (Marine)
AB: In the southeastern pacific there are several large quasipermanent zones of upwelling, divergence, as well as frontal zones. For this reason, this is a region of high biological productivity. Much of the total biological resources of the oceans are present here, and as much as 20 percent of the world fish landings are made in this region. Previous investigations have shown the important combination of bacterioplankton to the food resources of the pelagic zone of the oceans. During the 34th cruise of the RV Akademik kurchatov , the authors investigated the function of the bacterioplankton.
AN: 1081531
132 of 369
TI: Biogeochemical influence of vegetation and soils in the ILWAS watersheds.
AU: Cronan,-C.S.
AF: Dep. Bot. and Plant Pathol., Univ. Maine, Orono, ME 04469, USA
SO: WATER-AIR-SOIL-POLLUT. 1985. vol. 26, no. 4, pp. 355-371
NT: Special issue: Integrated Lake-Watershed Acidification.
LA: English
ER: F (Freshwater)
AB: The Integrated Lake-Watershed Acidification Study (ILWAS) was initiated to develop a quantitative mechanistic understanding of the relationship between atmospheric deposition and surface water quality and acidity. The study was conducted using three forested watersheds (Panther, Sagamore, and Woods) in the central Adirondack Park of New York State. Although these catchments receive similar loadings of acidic deposition, the three systems exhibit distinct differences in lake water pH and alkalinity (Panther Lake = pH 6.2, Sagamore Lake = pH 5.6, and Woods Lake = pH 4.7). By comparing the biogeochemical behavior of these watersheds, the ILWAS investigators hoped to elucidate and to quantify the major ecosystem parameters controlling the fate of strong acids introduced from the atmosphere to lake-watershed systems.
AN: 1080137
133 of 369
TI: Speciation of chemical elements in sediments of an eutrophicated and polluted lake basin in southern Finland.
AU: Alhonen,-P.; Vuorinen,-A.; Suksi,-J.
AF: Dep. Geol., Univ. Helsinki, Helsinki, Finland
CO: 7. International Symposium on Environmental Biogeochemistry, Viterbo (Italy). Rome (Italy), 8-13 Sep 1985
SO: 7th-INTERNATIONAL-SYMPOSIUM-ON-ENVIRONMENTAL-BIOGEOCHEMISTRY. 1985. p. 5
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: A sediment profile of an eutrophicated and polluted lake, Lake Lippajaervi was investigated for lithostratigraphy, lake productivity (including subfossil diatoms) and speciation of chemical elements. Sedimentation rate was on an average 10.5 mm/yr during the last twenty years, being ca. 8 mm/yr between 1963 and 1970 and ca. 13 mm/yr between 1970 and 1982. Biogeochemical cycles and processes have led to dissolution of remarkable amounts of elements from mineral matter and their binding in more loosely bound forms. The elements seem to be present as sorbed, as sulphides, and in association with Fe oxyhydroxides and with organic matter (Fe and Cu). As a consequence of eutrophication and pollution many elements were enriched in the upper parts of the sediment profile.
AN: 1073150
134 of 369
TI: The effects of natural water level fluctuations on N and P cycling in a Great Lakes marsh.
AU: Kelley,-J.C.; Burton,-T.M.; Enslin,-W.R.
AF: Dep. Fish. and Wildl., Michigan State Univ., East Lansing, MI 48824, USA
SO: WETLANDS. 1984. vol. 4, pp. 159-175
LA: English
ER: F (Freshwater)
AB: The water depth in marshes occurring along Lake Michigan is largely controlled by fluctuations of the Lake Michigan water level. The role of water level in controlling the distribution and cycling of N and P in emergent (Sparganium eurycarpum, Scirpus validus , and Typha latifolia ) and wet meadow (Calamagrostis canadensis, Carex stricta , and Carex aquatilis ) communities of a Lake Michigan river mouth marsh was studied. Nutrient uptake was determined from biomass sampling and tissue analysis. Community distribution at various lake stages was determined from aerial photographs.
AN: 1046531
135 of 369
TI: Arsenic transport, reactivity, and toxicity in the Chesapeake Bay.
AU: Sanders,-J.G.
CO: The Fate and Effects of Pollutants: A Symposium, (College Park, MD) (USA), 26-27 Apr 1985
SO: THE-FATE-AND-EFFECTS-OF-POLLUTANTS:-A-SYMPOSIUM. Maryland-Univ.,-College-Park-USA.-Sea-Grant-Program 1985. p. 55
ST: TECH.-REP.-MD.-UNIV.-SEA-GRANT-PROGRAM.
NT: Summary only.
RN: UM-SG-TS-85-02 (UMSGTS8502)
LA: English
ER: M (Marine); B (Brackish)
AB: Arsenate, the primary inorganic form of arsenic in oxidized natural waters, is highly reactive in productive estuaries, actively taken up by phytoplankton, transformed into reduced and methylated forms, then released into the surrounding water column. The degree of arsenic methylation that takes place is proportional to the rate of primary production and the chemical form of arsenic produced is dependent on the species of phytopolankton present. The various chemical forms of arsenic differ in their stability, reactivity, and toxicity; thus, the observed variations have considerable geochemical and ecological significance. Algal incorporation of arsenic and subsequent transformation of chemical form leads to an increase in reduced and methylated arsenicals which are less available (and, therefore, less toxic) to phytoplankton, but are much more toxic to higher organisms.
AN: 1046215
136 of 369
TI: A global biogeochemical cycle and the system organization.
OT: Global'nyj biogeokhimicheskij krugovorot khimicheskikh ehlementov i ego sistemnaya organizovannost'
AU: Norozov,-N.P.
AF: VNIRO, Moscow, USSR
SO: BIOGEOCHEMICAL-AND-TOXICOLOGICAL-STUDIES-OF-WATER-POLLUTION.. BIOGEOKHIMICHESKIE-I-TOKSIKOLOGICHESKIE-ISSLEDOVANIYA-ZAGRYAZNENIYA-VODOEMOV.- Patin,-S.A.-ed.1984. pp. 9-21
ST: SB.-NAUCH.-TR.-VNIRO.
LA: Russian
AB: A global biogeochemical embraces all migrations of chemical elements governed by biological, geological and physico-chemical processes and by human activities. However, the leading role is played by migrations of nutrients with live organisms, their metabolites and detritus. A multi-purpose approach to investigations of biogeochemical cycles in ecosystems will contribute to the solution of problems related to rational exploitation and protection of natural resources.
AN: 1037723
137 of 369
TI: The transport of major dissolved matter in Changjiang Estuary.
AU: Wang,-Z.-F.; Yuan,-X.-Z.; Yao,-L.-K.
AF: Second Inst. Oceanogr., Natl. Bur. Oceanogr., Hangzhou, People's Rep. China
SO: OCEANOL.-LIMNOL.-SIN. 1985. vol. 16, no. 3, pp. 222-230
LA: Chinese
ER: B (Brackish)
AB: The average concentrations (ppm) of major dissolved matter in Changjiang River are: SiO sub(2), 6.2, Ca 35.0, Mg 5.5, Na 9.0, K 2.2, Cl 20, SO sub(4) 13.5, HCO sub(3) 127, among them the most concentrated species are Ca and HCO sub(3). In the area studied, major dissolved elements are controlled by the physical mixing because they are linearly related with C1ppt, which also indicates a behavir of conservation. The correlations are: Na = -1.6 + 540 Cl Clppt. less than or equal to 1; Na = -64.8 + 539.5 Cl Clppt >1; K = 1.53 + 23.7 Cl; Ca = 34.8 + 19.6 Cl; Mg = 2.75 + 68.5 Cl; SO sub(4) = 9.43 + 140.1 Cl; HCO sub(3) = 126.5 + 0.69 Cl; and SiO sub(2) = 6.24-0.17S. The fluxes of the major dissolved matter in the Changjiang Estuary were also estimated as follows: Na 8.4 x 10 super(6)t/a; K 2.0 x 10 super(6)t/a; Ca 31.9 x 10 super(6)t/a; SO sub(4) 12.3 x 10 super(6)t/a; Mg 5.2 x 10 super(6)t/a; HCO sub(3) 116.4 x 10 super(6)t/a; SiO sub(2) 5.7 x 10 super(6)t/a; and Cl 18.5 x 10 super(6)t/a sub(o).
AN: 1035841
138 of 369
TI: Extraction and cleanup procedures for determination of diarylphosphates in fish, sediment, and water samples.
AU: Muir,-D.C.G.; Grift,-N.P.
AF: Freshwat. Inst., Dep. Fish. and Oceans, 501 University Crescent, Winnipeg, Man. R3T 2N6, Canada
SO: J.-ASSOC.-OFF.-ANAL.-CHEM. 1983. vol. 66, no. 3, pp. 684-690
LA: English
AB: Methods for determination of triaryl/alkylphosphates (TAPs) in water, fish, and sediment have been extended to determination of the diarylphosphate (DAP) degradation products. DAPs were extracted from water (adjusted to pH 0.5) by use of XAD-2 resin and determined by gas-liquid chromatography as butyl esters. Recovery of diphenylphosphate (DPP) and o-, m-, p-dicresylphosphates (DoCP, DmCP, DpCP) were >95% in water samples fortified at 1, 10, and 50 mu g/L. DAPs were extracted from fish with methanol and the extracts were cleaned up on reverse phase (C18) silica cartridges. Recoveries were >87% for DPP, DoCP, DmCP, and DpCP in fish muscle fortified at 50, 100, and 500 ng/g. Sediments were refluxed with aqueous methanol and DAPs were recovered by use of XAD-2 resin. Recoveries of DAPs from sediments fortified at 50 and 100 ng/g were >76%. Interferences (1-10 ng/g) from phosphorus or nitrogen-containing GLC peaks prevented sub-ng/g level analysis for DAPs in sediment and fish extracts.
AN: 1033824
139 of 369
TI: Cycling of fluoride in a mangrove community near a fluoride emission source.
AU: Murray,-F.
AF: Dep. Biol. Sci., Univ. Newcastle, Newcastle, N.S.W. 2308, Australia
SO: J.-APPL.-ECOL. 1985. vol. 22, no. 1, pp. 277-285
LA: English
ER: B (Brackish)
AB: A comparison of stands of immature grey mangroves, Avicennia marian growing near a fluoride emission source (Kooragang Island, Australia) and a relatively unpolluted area (Gosford) showed that A. marina and accumulate high concentrations of fluoride, particularly in leaves, generally without visible injury. Fluoride input to the Kooragang Island ecosytem as bulk deposition of fluoride was found to be 0 multiplied by 31 g m super(-2) year super(-1) and this varied with the distance and direction of each site in relation to fluoride emission sources. Most of the input at Kooragang Island was gaseous fluoride, but a small particulate fluoride input occurred. Mangrove communities may export up to 25 kg ha super(-1) day super(-1) of detritus to estuarine food webs of commercial and ecological importance, so the fluoride retentive capacity of mangrove communities is of potential significance when industrial emission sources establish in these estuarine areas.
AN: 1031386
140 of 369
TI: Composition of alkanes and fatty acids of lipids in suspended organic matter and sediments from the Northwest Indian Ocean.
OT: Sostav alkanov i zhirnykh kislot lipidov vzvesi i osadkov severo-zapadnoj chasti Indijskogo okeana
AU: Nemirovskaya,-I.A.; Verkhovskaya,-Z.I.
AF: Inst. Okeanol. AN SSSR, Moscow, USSR
SO: GEOKHIMIYA. 1985. no. 6, pp. 891-898
LA: Russian
ER: M (Marine)
AB: Based on samples collected during the 32nd cruise of the R/V Akademik Kurchatov in March and April 1981 an analysis was made of the composition of alkanes in suspended matter obtained by separation and filtration and of alkanes and fatty acids from the upper bottom sediments in the Mozambique Channel and the Seychelles area. The alkanes were mainly C sub(16) - C sub(35) compounds. In individual samples the alkane spectrum was characterized by 2 maxima: n - C sub(17) and n C sub(25) - C sub(31). C sub(13) - C sub(20) enter into fatty acids with saturated C sub(16), C sub(18) and unsaturated C sub(18), C sub(20) predominating. It is shown that alkanes and fatty acids are of both of terraneous and marine origin at various ratios of allochthonic and antochthonous components, the latter playing a more important role at the stations located in the immediate vicinity of oil- and gas-bearing formations.
AN: 1023877
141 of 369
TI: Biogeochemical processes and climate modelling.
AU: Bolin,-B.
AF: Dep. Meteorol., Univ. Stockholm, Stockholm, Sweden
SO: THE-GLOBAL-CLIMATE. Houghton,-J.T.-ed. 1984. pp. 213-224
LA: English
ER: M (Marine)
AB: Some basic steady state features of the global biogeochemical cycles are reviewed, particularly with regard to turnover times for carbon in terrestrial and marine reservoirs, and the means for their determination. The processes of evapo-transpiration, the dependence of surface albedo on type of vegetation and moisture supply photosynthesis and gaseous exchange between the atmosphere and plants are analysed as is their possible role in modelling long-term changes of climate. Similarly, the role of the nutrient balance of the sea for climate change is discussed.
AN: 1021455
142 of 369
TI: Effects of benthic macroinvertebrates on the exchange of solutes between sediments and freshwater.
AU: Matisoff,-G.; Fisher,-J.B.; Matis,-S.
AF: Dep. Geol. Sci., Case Western Reserve Univ., Cleveland, OH 44106, USA
SO: HYDROBIOLOGIA. 1985. vol. 122, no. 1, pp. 19-33
LA: English
ER: F (Freshwater)
AB: Infaunal macrobenthos (tubificid oligochaetes, chironomid larvae, and unionid bivalves) were studied in laboratory microcosms to determine their effects on freshwater sediment diagenesis and the exchange of solutes between sediments and water. Tubificids enhanced the flux of ammonium, bicarbonate, and silica from sediments. After the onset of anoxia, they decreased the flux of iron and phosphate. Chironomids increased the flux of nitrate, bicarbonate, and silica, but did not affect the flux of phosphate. Pore water concentrations were low within the irrigated burrowed zone for chemical species normally high in reduced sediments. Concentration gradients were less steep in the actively irrigated burrow zone, but radial diffusion to and from burrows, increased rates of organic decomposition, and enhanced diatom frustule dissolution rates result in enhanced mass transport from sediments.
AN: 1019837
143 of 369
TI: Particulates and the cycling of lead in Ullswater, Cumbria.
AU: Everard,-M.; Denny,-P.
AF: Sch. Biol., Queen Mary Coll., Mile End Rd., London E1 4NS, UK
SO: FRESHWAT.-BIOL. 1985. vol. 15, no. 2, pp. 215-226
LA: English
ER: F (Freshwater)
AB: Ullswater has been affected by former lead mining in the catchment area. This paper investigates how lead in the lake is re-distributed within the littoral zones. Concentrations in the lakewater are low. Particulates including phytoplankton, seston and gelatinous ooze overlying lead-enriched sediments can have values from 1.3 to > 6.0 and 26 mg Pb g super(-1) dry weight respectively.
AN: 1016232
144 of 369
TI: Prospects for global ocean pollution monitoring.
CA: UNEP, Geneva (Switzerland)
SO: UNEP-REG.-SEAS-REP.-STUD. GENEVA-SWITZERLAND-UNEP 1984. no. 47, 58 pp
LA: English
ER: M (Marine)
AB: The oceans cover 70% of the earth's surface and are thus a major component of the environment. They play a significant role in biogeochemical cycles, in stabilising climate, and in providing marine resources. Therefore it is important that man's polluting activities are not allowed to impair this system. It is necessary for man to obtain a fundumental understanding of marine systems and to monitor the levels and effects of pollutants.
AN: 0977423
145 of 369
TI: Wetland research and NASA: Towards a planetary ecological perspective.
AU: Bartlett,-D.S.
AF: NASA Langley Res. Cent., Hampton, VA, USA
CO: 8. Biennial International Estuarine Research Conf., Durham, NH (USA), 28 Jul 1985
SO: ESTUARIES. 1985. vol. 8, no. 2B, p. 4A
NT: Abstract only.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The National Aeronautics and Space Administration (NASA) has begun a "Global Biospheric Research Program", which attempts to bring a planetary perspective to ecological studies. The objective of the program is to apply NASA technology and expertise from a number of relevant areas to establish a greater understanding of the influence of the biota on global material cycling. Investigations of wetlands have been chosen for particular emphasis because of their potentially important role in global nutrient cycling and of the active body of biogeochemical research taking place in wetland environments.
AN: 0976292
146 of 369
TI: (Role of circulation in the Alboran Sea in the vicinity of the Strait of Gibraltar, on the production-regeneration system (MEDIPROD cruise IV of Jean Charcot ).).
OT: Role de la circulation en mer d'Alboran au voisinage du detroit de Gibraltar, sur le systeme production-regeneration (Campagne MEDIPROD IV du Jean-Charcot )
AU: Minas,-M.; Coste,-B.; le-Corre,-P.; Minas,-H.J.; Packard,-T.T.; Raimbault,-P.
AF: Fac. Sci. Luminy, 13288 Marseille Cedex 09, France
SO: RAPP.-P.-V.-REUN.-CIESM. 1983. vol. 28, no. 7, pp. 59-61
LA: French
ER: M (Marine)
AB: Two phenomena can explain the nutrient enrichment leading to the high chlorophyll area off the Spanish coast in the northwestern Alboran Sea: A the turbulent mixing in the Strait of Bigraltar; - the Spanish coastal upwelling, associated with the anticyclonic gyre. The high productivity area produces, by organic sedimentation, a well-formed oxygen minimum and a regeneration layer in the Alboran Sea.
AN: 0964532
147 of 369
TI: (Comparison of the chemical composition of particles and plankton of the Liguro-Provencal Basin.).
OT: Comparaison de la composition chimique des particules et du plancton du Bassin Liguro-Provencal
AU: Haerdstedt-Romeo,-M.; Copin-Montegut,-C.
AF: Lab. Phys. et Chim. Mar., Univ. Pierre et Marie Curie, B.P. 8, La Darse, 06230 Villefranche-sur-Mer, France
SO: RAPP.-P.-V.-REUN.-CIESM. 1983. vol. 28, no. 7, pp. 63-65
LA: French
ER: M (Marine)
AB: The concentrations of C, N, P, Al, Fe and Si have been determined in plankton and particulate matter in the Liguro-Provencal Basin during March 80. Trace metals: Mn, Zn, Cu and Cd have been also analyzed in the plankton. C, N, Al, Fe and Si exhibit parallel variations in plankton and particulate matter.
AN: 0964166
148 of 369
TI: (Origin, distribution and evolution of organic matter in deposits of two Mediterranean lagoon ecosystems.).
OT: Origine, distribution et evolution de la matiere organique dans les depots de deux ecosystems lagunaires mediterraneens
AU: Gadel,-F.; Martin,-R.; Dumas,-J.P.
AF: Lab. Sedimentol. et Geochim. Mar., Univ. de Perpignan, France
SO: RAPP.-P.-V.-REUN.-CIESM. 1983. vol. 28, no. 7, pp. 115-118
LA: French
AB: The study of the organic matter determined the main factors responsible for the sedimentation of two Mediterranean lagoons composition of the organic matter results from its origin (phanerogamic, algal). It is distributed according to the dynamic and chemical environmental conditions. The evolution proceeds from the presedimentary alteration phenomena in freewater environment and diagenetic effects after deposition.
AN: 0964163
149 of 369
TI: The distribution of cadmium, copper, nickel, manganese, and aluminum, in surface waters of the open Atlantic and European shelf area.
AU: Kremling,-K.
AF: Inst. Meereskd., Duesternbrooker Weg 20, D-2300 Kiel, FRG
SO: DEEP-SEA-RES. 1985. vol. 32, no. 5A, pp. 531-555
LA: English
ER: M (Marine)
AB: A total of 232 surface water samples (6 m depth) was collected in the open Atlantic Ocean and in the Brazilian and northwest European shelf areas during three transects between 23 degree S and 59 degree N in October/November 1980, August/September 1981, and March/April 1982. The open Atlantic cadmium, copper, and nickel concentrations increase towards higher latitudes. These elevations are probably the result of the biogeochemical cycles of these elements and of the hydrographical regimes in those regions. A significant increase of all metals studied is observed at the northwest European shelf edge area. A comparison with waters of the central North Sea indicates enrichment factors of about 3 to 5 for the metals investigated here. The mechanisms that potentially may affect the shelf water concentrations are discussed on the basis of their relations with salinity.
AN: 0959453
150 of 369
TI: Experimental study of long-lived radionuclides transfers (americium, plutonium, technetium) between labelled sediments and Annelidae (Nereis diversicolor, Arenicola marina ).
AU: Germain,-P.; Miramand,-P.; Masson,-M.
AF: Comm. Energ. At., IPSN-DERS-SERE Lab. Radioecol. Mar., Cent. La Hague, B.P. 270, 50107 Cherbourg, France
CO: International Symposium on the Behavior of Long-lived Radionuclides in the Marine Environment, La Spezia (Italy), 28-30 Sep 1983
SO: INTERNATIONAL-SYMPOSIUM-ON-THE-BEHAVIOR-OF-LONG-LIVED-RADIONUCLIDES-IN-THE-MARINE-ENVIRONMENT. Cigna,-A.;Myttenaere,-C.-eds. Commission-of-the-European-Communities,-Luxembourg-Luxembourg 1984. pp. 327-340
ST: RADIAT.-PROT.-SER.
NT: ISBN 92-825-5089-3.
RN: EUR-9214-EN (EUR9214EN)
LA: English
ER: M (Marine)
AB: Laboratory experiments were conducted to determine the bioavailability of sediments labelled by super(241)Am, super(238)Pu, super(239)Pu and super(95m)Tc to two marine benthic annelidae: N. diversicolor and A. marina . Channel coastal sediments and atlantic sediments originating from Abyssal plain of Cape Verde were contaminated. The biological availability was expressed in terms of a transfert factor (T.F.) defined as the activity in the organisms (cpm.g super(-1) wet weight) relative to the activity in the sediment (cpm.g super(-1) wet weight). For both species and the three radionuclides, the transfer factors were lower than unity. In the case of reduced sediment, T.F. of super(95m)Tc (< 0.5) were higher than those of Am and Pu(< 0.01). The bounding of Tc with oxidative sediments is low and reversible, and T.F. are not significant, which is not the case with Am and Pu. Transfer modalities, indirect transfer via interstitial water and/or direct transfer from sediments, were discussed.
AN: 0958515
151 of 369
TI: Microbial sterility and salinity effects on super(241)americium distribution and biological transfer coefficients, in sandy marine and freshwater sediments.
AU: Vanderborght,-O.L.J.; van-Puymbroeck,-S.; Gerits,-J.; Vangenechten,-J.; Bierkens,-J.
AF: Belgian Nucl. Cent. SCK/CEN, Radionuclides Metab. Lab., B 2400 Mol, Belgium
CO: International Symposium on the Behavior of Long-lived Radionuclides in the Marine Environment, La Spezia (Italy), 28-30 Sep 1983
SO: INTERNATIONAL-SYMPOSIUM-ON-THE-BEHAVIOR-OF-LONG-LIVED-RADIONUCLIDES-IN-THE-MARINE-ENVIRONMENT. Cigna,-A.;Myttenaere,-C.-eds. Commission-of-the-European-Communities,-Luxembourg-Luxembourg 1984. pp. 317-325
ST: RADIAT.-PROT.-SER.
NT: ISBN 92-825-5090-3.
RN: EUR-9214-EN (EUR9214EN)
LA: English
ER: M (Marine)
AB: Microbial activity in sediments is often called upon as a factor that could change the mobility and the biological availability of transuranics. Experimental data on super(241)Am are scarce. The authors' former data indicated low K sub(d) values for super(241)Am in sandy marine and freshwater sediments (9.1 x 10 super(4)), values that did not significantly change by gamma -sterilization. In contrast, most reported k sub(d) values are situated at about 1.10 super(4) to 50.10 super(4). The authors report an extensive experiment to check in controlled conditions, the effect of microbial sterility of sediments, on super(241)Am K sub(d) and on its bioaccumulation by detritus feeders. A first approach to the situation in which a continental radioactive sediment would be flooded by seawater was also simulated by adding seawater to freshwater sediments.
AN: 0958452
152 of 369
TI: Behaviour of tritium in the marine environment: Studies with the macroalgae Laurencia obtusa and Cystoseira compressa .
AU: Cinelli,-F.; Belcari,-P.; De-Ranieri,-S.; Arapis,-G.; Bonotto,-S.; Gerber,-G.B.; Kirchmann,-R.
AF: Ist. Zool. e Anat. Comp., Univ. Pisa, I-56100 Pisa, Italy
CO: International Symposium on the Behavior of Long-lived Radionuclides in the Marine Environment, La Spezia (Italy), 28-30 Sep 1983
SO: INTERNATIONAL-SYMPOSIUM-ON-THE-BEHAVIOR-OF-LONG-LIVED-RADIONUCLIDES-IN-THE-MARINE-ENVIRONMENT. Cigna,-A.;Myttenaere,-C.-eds. Commission-of-the-European-Communities,-Luxembourg-Luxembourg 1984. pp. 271-282
ST: RADIAT.-PROT.-SER.
NT: ISBN 92-825-5089-3.
RN: EUR-9214-EN (EUR9214EN)
LA: English
ER: M (Marine)
AB: Kinetic experiments with tritium water have shown that in the marine pluricellular algae L. obtusa and C. compressa , water equilibrates rapidly with external tritium water (5 mu Ci ml super(-1)). Two components were found in uptake, having respectively a half life of 0.2-0.4 and of 3.3.-22 min. In release, three components could be discerned, with half lives of 0.25, 4 and approximately equals 75-500 min. Incorporation of super(3)H into the total organic matter of Cystoseira), incubated in tritium water (50 mu Ci ml super(-1)) for 8-11 days, is small (0.6 to 2.5 mu Ci g super(-1) or 1-5% only). Selective extraction of freeze-dried Cystoseira has shown that 32% and 36% of tritium was bound respectively to small organic molecules and to lipids and pigments, whereas 20%, 11% and 0.4% of total organic tritium was present respectively in nucleic acids, protein and residual material.
AN: 0958361
153 of 369
TI: The chemical behavior of long-lived radionuclides in the marine environment.
AU: Edgington,-D.N.; Nelson,-D.M.
AF: Cent. Great Lakes Stud., Univ. Wisconsin, Milwaukee, WI 53204, USA
CO: International Symposium on the Behavior of Long-lived Radionuclides in the Marine Environment, La Spezia (Italy), 28-30 Sep 1983
SO: INTERNATIONAL-SYMPOSIUM-ON-THE-BEHAVIOR-OF-LONG-LIVED-RADIONUCLIDES-IN-THE-MARINE-ENVIRONMENT. Cigna,-A.;Myttenaere,-C.-eds. Commission-of-the-European-Communities,-Luxembourg-Luxembourg 1984. pp. 19-66
ST: RADIAT.-PROT.-SER.
NT: ISBN 92-825-5089-3.
RN: EUR-9214-EN (EUR9214EN)
LA: English
ER: M (Marine)
AB: Measurements of long-lived radionuclides in the marines environment have provided a wealth of information regarding the physical, biological, and chemical processes which control the behavior of these and many other pollutants in the oceans. Their value as tracers for the dispersion, transport, and fate of pollutants in the oceans is largely dependent on the chemical properties of each individual radioelement. Differences in these properties, particularly in relation to their interaction with biotic or abiotic particulate matter, result in the separation of parent-daughter radioisotopes in the natural radioelement series or in changes in the ratios of fission and activation products. Such differences have provided the means to provide time scale for a variety of transport processes and to determine sedimentation rates. the properties of these radionuclides in the oceans can, in general, be predicted from the chemical properties of the stable elements.
AN: 0957859
154 of 369
TI: The environmental behavior of long-lived radionuclides: Radiological protection requirements.
AU: Preston,-A.
AF: Minist. Agric., Fish. Food Fish. Lab., Lowestoft, Suffolk NR33 0HT, UK
CO: International Symposium on the Behavior of Long-lived Radionuclides in the Marine Environment, La Spezia (Italy), 28-30 Sep 1983
SO: INTERNATIONAL-SYMPOSIUM-ON-THE-BEHAVIOR-OF-LONG-LIVED-RADIONUCLIDES-IN-THE-MARINE-ENVIRONMENT. Cigna,-A.;Myttenaere,-C.-eds. Commission-of-the-European-Communities,-Luxembourg-Luxembourg 1984. pp. 3-15
ST: RADIAT.-PROT.-SER.
NT: ISBN 92-825-5089-3.
RN: EUR-9214-EN (EUR9214EN)
LA: English
ER: M (Marine)
AB: Radiological protection concern with long-lived radionuclides in the environment is examined and requirements in relation to the behaviour of such radionuclides in the environment are considered.
AN: 0957839
155 of 369
TI: International Symposium on the Behavior of Long-lived Radionuclides in the Marine Environment.
AU: Cigna,-A.; Myttenaere,-C.-(eds.)
AF: ENEA, Dip. Prot. Ambientale e Salute, Uomo Cent. Ric. Energ. Ambiente, Forte di Santa Teresa, La Spezia, Italy
CA: Commission of the European Communities, Luxembourg (Luxembourg)
CO: International Symposium on the Behavior of Long-lived Radionuclides in the Marine Environment, La Spezia (Italy), 28-30 Sep 1983
SO: RADIAT.-PROT.-SER. 1984. 471 pp
NT: ISBN 92-825-5089-3.
RN: EUR-9214-EN (EUR9214EN)
LA: English
ER: M (Marine)
AB: Abstracts of the 27 papers presented at the conference are cited. A brief discussion follows each paper. A round table discussion follows the proceedings.
AN: 0957796
156 of 369
TI: Arsenic in marine organisms. A minireview.
AU: Maher,-W.A.
AF: Dep. Phys. and Inorg. Chem., Univ. Adelaide, Adelaide, S.A., Australia
SO: BIOL.-TRACE-ELEM.-RES. 1984. vol. 6, no. 2, pp. 159-164
LA: English
ER: M (Marine)
AB: A review of the nature and accumulation of arsenic in marine organisms is presented. A study of the literature has revealed a lack of information about the mechanisms of uptake, molecular transformations, and biochemical associations of arsenic within organisms, and it remains unclear whether a few forms of arsenic are ubiquitous. The arsenic forms present in marine sediments and their role in the biogeochemical cycling of arsenic are also largely unknown.
AN: 0953546
157 of 369
TI: Accumulation of sediment organic matter in a hardwater lake with reference to lake ontogeny.
AU: Godshalk,-G.L.; Wetzel,-R.G.
AF: Dep. Biol. Sci., Univ. Southern Mississippi, Southern Station Box 5018, Hattiesburg, MS 39406, USA
CO: Symposium on Detritus Dynamics in Aquatic Ecosystems, Savannah, GA (USA), Nov 1983
SO: SYMPOSIUM-ON-DETRITUS-DYNAMICS-IN-AQUATIC-ECOSYSTEMS. 1984. vol. 35, no. 3 pp. 576-586
ST: BULL.-MAR.-SCI. vol. 35, no. 3
LA: English
ER: F (Freshwater)
AB: The occurrence and quality of detrital organic matter was investigated in sediments of a small hardwater lake. The objective of the study was to examine the interactions between plant productivity and growth form, water depth, sediment depth and potential erosion and deposition processes in the lake and their mutual impact on accumulation of detritus in the sediments. Of particular interest are the potential effects such accumulation has on sediment dynamics and lake ontogeny. Sediment core samples were taken on a transect from the water's edge to the deepest part of the lake. Samples of surficial, intermediate and deep sediments from all water depths were analyzed for content of coarse particulate matter, organic matter, solvent-extractable humins and fulvic and humic acids. The observed occurrence of sedimentary detrital carbon is explained in terms of hypothesized synergistic effects of increasing production and succession of littoral vegetation, differential decomposition rates controlled by properties of both the substrate and the microenvironment and the influence of water movements and basin morphology on sediment erosion and deposition. Results are discussed.
AN: 0947896
158 of 369
TI: Alternate fate of planktonic detritus: Organic deposition and the geological record.
AU: Porter,-K.G.
AF: Dep. Zool., Univ. Georgia, Athens, GA 30602, USA
CO: Symposium on Detritus Dynamics in Aquatic Ecosystems, Savannah, GA (USA), Nov 1983
SO: SYMPOSIUM-ON-DETRITUS-DYNAMICS-IN-AQUATIC-ECOSYSTEMS. 1984. vol. 35, no. 3 pp. 587-600
ST: BULL.-MAR.-SCI. vol. 35, no. 3
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Extensive deposits of amorphous and fine grained organic matter called black shale are found in the geological record. These deposits were formed in open water marine and freshwater systems as evidenced by the presence of planktonic microfossils including zooplankton fecal pellets. Fecal pellets are easily identifiable particles found among sedimenting planktonic material. An examination of morphometric and ecological conditions favoring pellet deposition today allows one to reconstruct the paleoecological environments at the time black shale formed. Loss of organic matter from the pellets through microbial degradation and coprophagy is reduced by cool water temperatures and brief residence time in the water column. Pellet preservation in sediments is enhanced in areas with minimal physical disturbance, bioturbation, and microbial activity. These conditions are generally well met in anoxic, silled marine basins, trenches, fjords, and permanently anoxic lakes.
AN: 0947765
159 of 369
TI: Symposium on Detritus Dynamics in Aquatic Ecosystems, sponsored by the Oceanography Section of the National Science Foundation, Center for Environmental and Estuarine Studies of the University of Maryland, and Skidaway Institute of Oceanography of the University of Georgia, Savannah, Georgia, November 1983.
CO: Symposium on Detritus Dynamics in Aquatic Ecosystems, Savannah, GA (USA), Nov 1983
SO: BULL.-MAR.-SCI. 1984. vol. 35, no. 3, 356 pp
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Twenty-eight papers from this conference are published in this issue.
AN: 0947322
160 of 369
TI: Ecology of Indian estuaries.10. Distribution of total phosphorus, total nitrogen and total potassium in the sediments of Ashtamudi Estuary.
AU: Balakrishnan-Nair,-N.; Abdul-Azis,-P.K.; Arunachalam,-M.; Krishnakumar,-K.; Dharmaraj,-K.
AF: Dep. Aquat. Biol. and Fish., Univ. Kerala, Trivandrum-695 007, India
SO: MAHASAGAR. 1984. vol. 17, no. 1, pp. 33-39
LA: English
ER: B (Brackish)
AB: The distribution of total phosphorus, total nitrogen and total potassium in the sediments of Ashtamudi, a tropical estuarine system (8 degree 53'-9 degree 2'N latitude and 76 degree 31'-76 degree 41'E longitude) has been studied from riverine to marine area in relation to the texture of the sediment and hydrographical features of the bottom waters. The values of total phosphorus, total nitrogen and total potassium are in the range 0.63-7.32 mg.g super(-1), 1.49-13.78 mg.g super(-1) and 0.4-3.1 mg.g super(-1) respectively. The pattern of distribution of total P with the textural relationship is discussed. The input of allochthonous phosphates from sewage is traced in the system. The reason for the higher values for total nitrogen in the riverine area is attributable to the admixture of industrial and agricultural wastes.
AN: 0947309
161 of 369
TI: Ecology of Indian estuaries. 8. Inorganic nutrients in the Ashtamudi Estuary.
AU: Balakrishnan-Nair,-N.; Dharmaraj,-K.; Abdul-Azis,-P.K.; Arunachalam,-M.; Krishnakumar,-K.; Balasubramanian,-N.K.
AF: Dep. Aquat. Biol. and Fish., Univ. Kerala, Trivandrum-695 007, India
SO: MAHASAGAR. 1984. vol. 17, no. 1, pp. 19-32
LA: English
ER: B (Brackish)
AB: Ashtamudi Backwater is the second largest estuarine system of the southwest coast of India. Surface and bottom waters from 52 stations covering the entire watershed from the lower reaches of the Kallada River to the mouth of estuary have been analysed. Data pertaining to temperature, salinity, transparency, pH, dissolved oxygen, phosphate-phosphorus, silicate-silicon, nitrate-nitrogen and nitrite-nitrogen are presented and discussed. Various sources of pollution, deposition and filling and their impact on the exosystem are also discussed. All parameters exhibited wide spatial and zonal variations governed mainly by mixing, nature and intensity of water pollution and other human interference. Results of the analyses are statistically compared. Phosphate-phosphorus and slicate-silicon are available throughout the watershed. Depletion of nitrate-nitrogen and nitrite-nitrogen has been observed in certain heavilly polluted regions.
AN: 0947219
162 of 369
TI: Contribution of gaseous sulphur from salt marshes to the global sulphur cycle.
AU: Steudler,-P.A.; Peterson,-B.J.
AF: Ecosyst. Cent., Mar. Biol. Lab., Woods Hole, MA 02543, USA
SO: NATURE. 1984. vol. 311, no. 5985, pp. 455-457
LA: English
ER: B (Brackish)
AB: The authors report here a synthesis of the results of an annual set of monthly flux measurements of hydrogen sulphide (H sub(2)S), dimethyl sulphide (DMS), carbonyl sulphide (COS), carbon disulphide (CS sub(2)) and dimethyl disulphide (CMDS) from a Spartina) marsh and an adjacent tidal creek. Dimethyl sulphide and H sub(2)S were the predominant gases released from the Spartina) marsh (49% and 35% of the total, respectively) while H sub(2)S was the major gas (71%) emitted from the creek site. They suggest that the short-lived sulphur gases released from marshes may have an important role in local atmospheric sulphur budgets. Globally, saline marshes may release a total of 1.7 Tg S yr super(-1) (1 Tg = 10 super(12) g) in the atmosphere, which includes more than double the quantity of two important long-lived sulphur gases, COS and CS sub(2), needed to sustain the stratospheric sulphate layer.
AN: 0942365
163 of 369
TI: Metals analysis in aquatic sediments. A review.
AU: Boniforti,-R.
AF: Lab. Stud. Ambiente Mar., CNEN-EURATOM, Fiascherino, La Spezia, Italy
SO: THALASSIA-JUGOSL. 1978. vol. 14, no. 3-4, pp. 281-301
NT: Incl. bibliogr.: 68 ref.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: In environmental pollution studies it is of great importance to know the distribution of metals in sediments, water, and biological material in order to evaluate the stresses imposed on the environment by anthropogenic activity. The availability of elements to organisms depends on their physicochemical state which in turn depends on the overall biogeochemical cycle. An important step of this cycle is the accumulation and/or release of elements by the sediments. Extraction methods used to investigate the distribution of metals in aquatic sediments are reviewed.
AN: 0938746
164 of 369
TI: Some aspects of biogeochemical cycles in the Red Sea with special reference to new observations made in summer 1982.
AU: Poisson,-A.; Morcos,-S.; Souvermezoglou,-E.; Papaud,-A.; Ivanoff,-A.
AF: Lab. Phys. Chim. Mar., Univ. Pierre et Marie Curie, Tour 24, 4 Place Jussieu, 75230 Paris Cedex 05, France
CO: Mabahiss/John Murray International Symposium, Alexandria (Egypt), 3 Sep 1983
SO: MARINE-SCIENCE-OF-THE-NORTH-WEST-INDIAN-OCEAN-AND-ADJACENT-WATERS. Angel,-M.V.-ed. 1984. vol. 31, no. 6-8A pp. 707-718
ST: DEEP-SEA-RES. vol. 31, no. 6-8A
LA: English
ER: M (Marine)
AB: Recent data of some parameters of the carbon dioxide system in the Red Sea are presented and discussed in relation to the distribution of nutrients, water budget and general circulation in the Red Sea. Special attention is focussed on the variation of distribution of these parameters from winter to summer, and on the two regimes of circulation in the straits of Bab-el-Mandab. This is based mainly on the measurements made on the Meteor in December 1964 and the new data collected during two recent cruises on the R/V. Maeio-Dufresne in June and October 1982.
AN: 0926544
165 of 369
TI: Biogeochemistry of particulate organic matter in the oceans: Results from sediment trap experiments.
AU: Wakeham,-S.G.; Lee,-C.; Farrington,-J.W.; Gagosian,-R.B.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES. 1984. vol. 31, no. 5A, pp. 509-528
LA: English
ER: M (Marine)
AB: Particulate organic matter collected in sediment traps from various oceanic regimes-Sargasso Sea, equatorial North Atlantic, central North Pacific, California Current, and Peru coastal upwelling-have been analyzed for their lipid and amino acid composition and flux. Despite rapid settling of the large particles through the water column and a relatively small depth gradient for total organic carbon flux, there are major changes in the composition and flux of lipids and amino acids associated with the particles. The rapid disappearance of the more labile compounds, such as amino acids and polyunsaturated fatty acids, with increasing depth indicates that the major sources of such compounds are in the upper part of the water column and that they are readily degraded as the particles sink. On the other hand, the intermittent appearance of large amounts of wax ester, along with the changing fatty acid composition of the particles, points to deep-water sources for some of these compounds.
AN: 0920865
166 of 369
TI: Antarctic freshwater algae.
AU: Wharton,-R.A.,Jr.
AF: NASA-Ames Res. Cent., Moffett Field, CA 94035, USA
CO: Annual Meeting of the Phycological Society of America, Fort Collins, CO (USA), 5-9 Aug 1984
SO: ABSTRACTS.-ANNUAL-MEETING-OF-THE-PHYCOLOGICAL-SOCIETY-OF-AMERICA,-1984. 1984. vol. 20, no. suppl. p. 11
ST: J.-PHYCOL. vol. 20, no. suppl.
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Less than 10% of Antarctica contains regions favorable to the growth and reproduction of algae. These regions included coastal areas of the Antarctic Peninsula and several ice free valleys along the margin of the continent. Directions of future research will likely include year-round field studies, laboratory studies of physiological-ecology, the role of algae in biogeochemical cycles, including sedimentation, mineral deposition, stromatolite formation, and understanding the paleoecology of antarctic freshwater ecosystems.
AN: 0909798
167 of 369
TI: Suspended sediments and nutrients in water ebbing from seagrass-covered and denuded tidal mudflats in a southern Australian embayment.
AU: Bulthuis,-D.A.; Brand,-G.W.; Mobley,-M.C.
AF: Mar. Sci. Lab., P.O. Box 114, Queenscliff, Vic. 3225, Australia
SO: AQUAT.-BOT. 1984. vol. 20, no. 3-4, pp. 257-266
LA: English
ER: M (Marine)
AB: The concentrations of suspended solids, nitrogen (NH sub(4)@)u+, NO sub(3)@)u-, NO sub(2)@)u-), phosphorus (total phosphorus, PO sub(4)@)u- super(3)) and silicate were measured in water ebbing from seagrass-covered tidal mudflats and from adjacent ungrassed mudflats in Western Port, Victoria, Australia. Ebb water was collected on six occasions during January and February (summer) and once during July (winter). From both types of mudflats the concentrations of suspended solids, phosphorus and silicate increased during the last hour of ebb tide with maxima in concentrations reached 0.5 to 1 h before slack water ebb. During the last 1.5-2.5 h of ebb tide the suspended solids, phosphorus and silicate concentrations were higher in water ebbing from denuded mudflats than from seagrass-covered mudflats. The concentration of nitrogen remained low in water ebbing from both types of mudflats during the day, but increased significantly during a night-time ebb; light-dependent biological uptake of nitrogen is implicated.
AN: 0887251
168 of 369
TI: The supersaturation of carbonyl sulfide in surface waters of the Pacific Ocean off Peru.
AU: Ferek,-R.J.; Andreae,-M.O.
AF: Dep. Oceanogr., Florida State Univ., Tallahassee, FL 32206, USA
SO: GEOPHYS.-RES.-LETT. 1983. vol. 10, no. 5, pp. 393-396
LA: English
ER: M (Marine)
AB: Carbonyl sulfide (COS) was found to be supersaturated by a factor averaging 2.6 with respect to the atmosphere in surface waters of the continental shelf of Peru. The degree of supersaturation was correlated with dissolved dimethyl sulfide (MDS) concentrations indicating a possible biogenic source of atmospheric COS. The oceanic source of COS could account for a substantial fraction of the COS flux to the atmosphere.
AN: 0876961
169 of 369
TI: Imitation study of spring phytoplankton bloom in the coastal "pelagial" of the Gulf of Finland.
OT: Imitatsionnoe modelirovanie vesennego tsveteniya fitoplanktona v "pelagiali" pribrezhnykh vod Finskogo zaliva
AU: Savchuk,-O.P.; Kolodochka,-A.A.
AF: Address not stated
SO: STATISTICAL-ANALYSIS-AND-MODELLING-OF-OCEANOLOGICAL-PROCESSES.. VEROYATNOSTNYJ-ANALIZ-I-MODELIROVANIE-OKEANOLOGICHESKIKH-PROTSESSOV.- Rozhkov,-V.A.-ed.LENINGRAD-USSR-GIDROMETEOIZDAT 1984. pp. 130-146
LA: Russian
ER: M (Marine)
AB: A one-dimensional model is formulated describing cycle of N and dynamics of O sub(2) caused by vertical transport and translocation of matter within the components of the model (phytoplankton, zooplankton, detritus, dissolved organic N, ammonium, nitrites, nitrates and O sub(2)) is presented. The model was calibrated and verified with reference to observations carried out in 2 areas of the Gulf. It is concluded that the model simulates large-scale evolutionary regularities of vertical structure of ecosystem during spring phytoplankton bloom and can be used to study inner mechanisms of the matter cycle in relation to changes in ecological factors.
AN: 0869148
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TI: Monitoring carbon in world rivers.
AU: Degens,-E.; Kempe,-S.; Ittekkot,-V.
AF: Inst. Geol. and Paleontol., Univ. Hamburg, Hamburg, FRG
SO: ENVIRONMENT-WASH.-DC. 1984. vol. 26, no. 9, pp. 29-33
LA: English
ER: F (Freshwater)
AB: Riverine systems play a major role in the transport of nutrients from the planet's land masses and atmosphere to its oceans, and frequently serve as reservoirs for numerous compounds. This project report outlines the activities and initial results of a unique research effort to measure the transport of nutrients--especially organic carbon--in major world rivers. Many scientists believe that the results of this study may aid them in determining some unknown parameters of the global carbon dioxide budget and in understanding how human actions have complicated the biogeochemical cycling of elements.
AN: 0865926
171 of 369
TI: Resistance of estuarine bacteria to organotin compounds.
AU: Pettibone,-G.W.; Cooney,-J.J.
AF: Univ. Massachusetts, Boston, MA 02125, USA
CO: 84. Annual Meeting of the American Society for Microbiology, St. Louis, MO (USA), 4-9 Mar 1984
SO: ABSTRACTS-OF-THE-ANNUAL-MEETING-OF-THE-AMERICAN-SOCIETY-FOR-MICROBIOLOGY-1984. 1984. p. 186
NT: Summary only.
LA: English
ER: B (Brackish)
AB: Pure cultures of estuarine bacteria were isolated and screened to determine resistance to increasing concentrations of (CH sub(3)) sub(2)SnCl sub(2). MIC's for 100 isolates ranged from 2.5 to greater than or equal to 200 ppm Sn as (CH sub(3)) sub(2)SnCl sub(2) and most (68%) had MIC's in the range of 15-50 ppm Sn. All pure cultures isolated on media containing 15 ppm Sn as (CH sub(3)) sub(2)SnCl sub(2) were resistant to (CH sub(3)) sub(3)SnCl. This suggests that resistance to one methyltin confers resistance to other methyltins. These results are consistent with the proposal that estuarine microflora can participate in biogeochemical cycling of tin.
AN: 0864848
172 of 369
TI: Detritus processing and mineral cycling in seagrass (Zostera ) litter in an Oregon salt marsh.
AU: Gallagher,-J.L.; Kibby,-H.V.; Skirvin,-K.W.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: AQUAT.-BOT. 1984. vol. 20, no. 1-2, pp. 97-108
LA: English
ER: B (Brackish)
AB: In estuaries where seagrass beds adjoin marshes, the import and decomposition of seagrass litter in the marsh provide a mechanism for retaining nutrients within the wetlands and preventing loss to adjacent oceanic waters. Several aspects of the influence of seagrass litter on an Oregon salt marsh were studied. The quantity of Zostera litter in the marsh vegetation depended on elevation and on the marsh-plant canopy structure. Litter decomposition was most complete in the seagrass bed and in the highest marsh area. Seagrass litter contributed between 14 and 31% as much dead material to the total litter in the marsh as did the marsh plants. Decomposition of this litter could release 6-8% of the nitrogen required for the growth of the marsh plants.
AN: 0862591
173 of 369
TI: Abstracts of the Annual Meeting of the American Society for Microbiology 1984.
CA: American Soc. for Microbiology, Washington, DC (USA)
CO: 84. Annual Meeting of the American Society for Microbiology, St. Louis, MO (USA), 4-9 Mar 1984
SO: WASHINGTON,-DC-USA-ASM 1984. 386 pp
NT: Summaries only.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The papers included from this conference deal with the role of microorganisms in aquatic ecosystems, microbial contamination of shellfish, waters, and sediments, and the physiology and metabolism of bacteria and viruses.
AN: 0862414
174 of 369
TI: Composition and origin of temperate skeletal carbonate sediments on South Maria Ridge, northern New Zealand.
AU: Nelson,-C.S.; Hancock,-G.E.
AF: Dep. Earth Sci., Univ. Waikato, Hamilton, New Zealand
SO: N.Z.-J.-MAR.-FRESHWAT.-RES. 1984. vol. 18, no. 2, pp. 221-239
LA: English
ER: M (Marine)
AB: South Maria (34 degree S) is a 1500 km super(2) submarine ridge and bank system, less than 500 m deep, slowly accumulating photic and subphotic, clean skeletal carbonate gravels and sands having over 80%, and generally over 95%, CaCO sub(3), mainly calcite. Contributing factors include the negligible supply of terrigenous sediment, the availability of stable rocky substrates for colonisation by epibenthos, and the prominent upwelling of nutrient-rich waters, stimulating organic growth. Sediments mainly comprise fragmental remains of diverse bryozoan colonies (10-74%), with lesser amounts of mainly infaunal bivalves (2-20%), gastropods (2-10%), ahermatypic corals (0-18%), calcareous red algae (1-16%), and benthic foraminifers (3-15%). Major species are identified. The distribution of skeletal types is controlled initially by substrate, bathymetry, and energy level, and subsequently by topographically influenced tidal flow dispersal. However, the present sediment distribution pattern has been complicated by eustatic sea level changes. Modern zones of carbonate production are centered mainly on the shallower portions of the ridge, in the vicinity of Three Kings and Middlesex Banks. Below 150-200 m depth the skeletal sediments become increasingly relict.
AN: 0837273
175 of 369
TI: The role of sulphide in the formation of dimethyl mercury in river and estuary sediments.
AU: Craig,-P.J.; Moreton,-P.A.
AF: Sch. Chem., Leicester Polytech., P.O. Box 143, Leicester, LE1 9BH, UK
SO: MAR.-POLLUT.-BULL. 1984. vol. 15, no. 11, pp. 406-407
LA: English
ER: B (Brackish); F (Freshwater)
AB: The role of sulphide-containing species in sediments in the mobilization of mercury in the environment is demonstrated. The mobile species is the volatile hydrophobic dimethyl mercury. Transport to atmosphere in this form may account for a loss of about 12% annually of methyl mercury from sediments and may therefore be a substantive part of the biogeochemical cycling of mercury in the environment.
AN: 0836766
176 of 369
TI: Biogeochemical behaviour of nitrate and phosphate in the ocean.
OT: Taiheiyo kaisui-chu no shosan-ion oyobi rinsan-ion no seikagakuteki kyodo
AU: Sagi,-T.; Miyake,-Y.; Saruhashi,-K.
AF: Nagasaki Mar. Obs., Minamiyamate-cho, Nagasaki, 850 Japan
SO: OCEANOGR.-MAG.-KISHO-CHO-OBUN-KAIYOHO. 1983. vol. 33, no. 1-2, pp. 1-18
LA: English
ER: M (Marine)
AB: Concentrations of nitrate and phosphate in sea water can be expressed as a sum of a constant term (primary concentration) and a variable term (plus or minus). In the upper layer from surface to 1 km, variation in concentration is caused mainly by organic production, while in the deeper layer, by decomposition of organic matters. Primary concentration is defined as concentration when biological production and AOU are zero. Calculations using observed values of nitrate ion concentration (N) and AOU at 54 stations in the Pacific showed that the relation between and AOU is linear, the ratio of their rates of change is 0.043 and the primary concentration is 20.2 mu g atoms liter super(-1). For phosphorus, ratio between rates of change of phosphate ion concentration (P) and AOU is 0.0029 and primary concentration is 1.58 mu g atoms liter super(-1) . Using these values, N and P were calculated below 1 km depth. Results agreed well with observations. N/P ratio in sea water is determined by difference between primary N/P ratio (12.8) and Delta N/ Delta P ratio (15). N/P ratio near the surface is lower than 12.8 due to biological production and higher in the deep layer up to 14.
AN: 0836580
177 of 369
TI: The vertical profiles of carbon, nitrogen, phosphorous and biogenic silica in sediment from the Bering Sea.
AU: Kamatani,-A.
AF: Tokyo Univ. Fish., Konan-4, Minatoku, Tokyo 108, Japan
SO: UMI-LA-MER. 1983. vol. 21, no. 4, pp. 198-206
LA: English
ER: M (Marine)
AB: A biogenic silica-rich core sample from the central Bering Sea was analyzed for total nitrogen and phosphorus, organic carbon and biogenic silica contents, and the results studied to evaluate the decomposition rates of these bioelements during diagenesis. Organic carbon, biogenic silica and total nitrogen contents decreased with depth. The content of total phosphorus was roughly constant throughout the core sediment, suggesting that phosphorus released to the overlying waters by way of the interstitial waters was sufficiently small to be considered negligible. The dissolution rate constants of biogenic silica were in the range of 1.2-2.8 x 10 super(-4) yr super(-1). The mineralization rate constants of organic carbon, calculated on biogenic silica-free basis, were 0.43-1.0 x 10 super(-4) yr super(-1). This can be ascribed to the high efficiency of the poor adsorption capacity of the biogenic silica-rich content of the Bering Sea sediment. Based on primary production in the euphotic zone, organic carbon flux was only 2%, whereas biogenic silica was 32-40%.
AN: 0833709
178 of 369
TI: Cycle of organic matter in deep water.
OT: Yukibutsu no dotai
AU: Tanoue,-E.
AF: Grad. Sch. Sci. Technol., Kobe Univ., Rokkodai, Nada-ku, Kobe, 657, Japan
CA: Soc. Franco-Japonaise Oceanogr., Tokyo (Japan)
Oceanogr. Soc. Japan (Japan)
CO: Carbohydrates, Proteins, Lipids, Nucleic Acids and other Organic Compounds of Phytoplankton in Aquatic Environments, Tokyo (Japan), 6 Apr 1983
SO: UMI-LA-MER. 1983. vol. 21, no. 4, pp. 241-248
LA: Japanese
AB: Fatty acid and monosaccharide compositions of sinking particles collected with sediment traps and particulate matter collected by filtration of seawater were compared and discussed. Organic materials in sinking particles from 0.1 through 5.25 km depths were mainly derived from phytoplankton in euphotic layers. These organic materials were highly susceptible to biological degradation and played a major active role in biological cycles even in intermediate and deep water layers. Rates of degradation of organic matter in the deep water layer estimated by the sediment trap method were found to be almost comparable to those obtained from the dissolved oxygen consumption rates reported in deep waters of various oceanic areas.
AN: 0832266
179 of 369
TI: Carbonate cycles in Aptian-Albian "black shales" of the Falkland Plateau.
AU: Parker,-M.E.; Arthur,-M.A.; Wise,-S.W.,Jr.
AF: Dep. Geol., Florida State Univ., Tallahassee, FL 32306, USA
SO: ANTARCT.-J.-U.S. 1983. vol. 18, no. 5, pp. 153-154
LA: English
ER: M (Marine)
AB: Cretaceous cores from Deep Sea Drilling Project (DSDP) leg 71, site 511, drilled on the eastern Falkland Plateau (51 degree 00.28'S 46 degree 58.30'W), were examined via carbonate, organic carbon, stable isotope, nannofloral, and ultrastructural analysis in an attempt to determine the mode of origin of thin but discrete pelagic limestone beds intercalated among the black mudstones (figure 2) near the top of the extensive Mesozoic "black-shale" sequence of the Falkland Plateau. The "black shales" are of interest because of their paleoenvironmental significance and their potential as a source rock for petroleum in and around the South Atlantic Basin. This article is a synopsis of a more extended work that has been submitted for publication elsewhere (Parker et al. in press).
AN: 0813098
180 of 369
TI: The association of iron and manganese with bacteria on marine macroparticulate material.
AU: Cowen,-J.P.; Silver,-M.W.
AF: Cent. Coastal Mar. Stud., Univ. California, Santa Cruz, CA 95064, USA
SO: SCIENCE-WASH.. 1984. vol. 224, no. 4655, pp. 1340-1342
LA: English
ER: M (Marine)
AB: Evidence of in situ metal (iron and manganese) deposition onto bacteria associated with rapidly sinking particles in the open ocean is reported. Below 100 meters, bacteria are found with extracellular capsules containing metal precipitates; the frequency of these capsules increases with depth. The capsular metal deposits appear to contribute a major portion of the weakly bound fraction of the particulate iron flux.
AN: 0800216
181 of 369
TI: Carbon production and export from Biscayne Bay, Florida. 1. Temporal patterns in primary production, seston and zooplankton.
AU: Roman,-M.R.; Reeve,-M.R.; Froggatt,-J.L.
AF: Univ. Maryland Cent. Environ. and Estuar. Stud., HPEL, P.O. Box 775, Cambridge, MD 21613, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1983. vol. 17, no. 1, pp. 45-59
LA: English
ER: M (Marine)
AB: Five stations along a transect from the western shore of Biscayne Bay, Florida to the Florida Current were sampled monthly for one year. The variability and amount of seston particulate organic carbon, adenosine triphosphate, chlorophyll a, primary production and zooplankton decreased along the seaward transect. The greater inshore biomass and variability of seston were the result of the allochthonous input of detritus and inorganic nutrients via terrestrial runoff. Annual primary production in this subtropical coastal lagoon ranged from 13 to 46 g C m super(-2)yr super(-1). In this clear, shallow (2 to 3 m), oligotrophic lagoon, over 90% of total primary production is by submerged macrophytes and benthic algae. The high zooplankton biomass in the bay in most likely sustained by macrophyte detritus and the resuspension of benthic diatoms by the high winds associated with summer squalls and winter cold fronts.
AN: 0798247
182 of 369
TI: Toward an International Geosphere-Biosphere Program: A study of Global Change. Report of a workshop held at Woods Hole, Massachusetts July 25-29, 1983.
CA: National Research Counc., Washington, DC (USA)
CO: Workshop Toward an International Geosphere-Biosphere Program: A study of Global change, Woods Hole, MA (USA), 25-29 Jul 1983
SO: 1983. 94 pp
NT: NTIS Order No.: PB84-161769.
LA: English
AB: Progress in fundamental areas of ocean-atmosphere interactions, biogeochemical cycles, and solar-terrestrial relationships has come far more slowly than in specialized fields, in spite of the obvious practical importance of such studies. If, however, we could launch a cooperative interdisciplinary program in the earth sciences, on an international scale, the authors might hope to take a major step toward revealing the physical, chemical and biological workings of the Sun-Earth system and the mysteries of the origins and survival of life in the biosphere. The concept of an International Geosphere-Biosphere Program (IGBP), as outlined in this report, calls for this sort of bold, "holistic" venture in organized research.
AN: 0792082
183 of 369
TI: The asphyxiation technique: An approach to distinguishing between molecular diffusion and biologically mediated transport at the sediment-water interface.
AU: van-der-Loeff,-M.M.R.; Anderson,-L.G.; Hall,-P.O.J.; Iverfeldt,-Aa.; Josefson,-A.B.; Sundby,-B.; Westerlund,-S.F.G.
AF: Neth. Inst. Sea Res., P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: LIMNOL.-OCEANOGR. 1984. vol. 29, no. 4, pp. 675-686
LA: English
ER: M (Marine); B (Brackish)
AB: On the assumption that lack of oxygen will cause the activity of benthic infauna to cease and thereby limit solute transport to that accomplished by molecular diffusion, the authors have measured the flux of dissolved silicate across the sediment-water interface of sediments incubated in situ under parallel benthic flux chambers. In one chamber the oxygen concentration was allowed to go to zero, and in the other the oxygen and pH remained at ambient values. As long as oxygen was present in the chambers, the measured summer and fall fluxes were 2-10 times those calculated from porewater profiles assuming one-dimensional molecular diffusion. After oxygen depletion, the silicate fluxes decreased and approached the values calculated on the basis of molecular diffusion.
AN: 0791945
184 of 369
TI: Depositional fluxes of metals and phytoplankton in Windermere as measured by sediment traps.
AU: Hamilton-Taylor,-J.; Willis,-M.; Reynolds,-C.S.
AF: Dep. Environ. Sci., Univ. Lancaster, Lancaster LA1 4YQ, UK
SO: LIMNOL.-OCEANOGR. 1984. vol. 29, no. 4, pp. 695-710
LA: English
ER: F (Freshwater)
AB: Monthly sediment trap samples collected from a deep water station (42 m) in Windermere for a period of 1 year were analyzed for 0.5 M HCl extractable and total Fe, Mn, Al, Pb, Cu, Zn, total C, N, and total solids. Concomitant algal counts showed the year to be fairly typical in terms of the known sequence of phytoplankton. The annual depositional fluxes are compared with previously determined values based on sediment studies. The ratio of the annual trap to sediment flux for Al ( less than or equal to 1) indicates the absence of local sediment resuspension. The ratios for Fe, Pb, and Zn (1.1, 1.4, and 1.5, but not significantly > 1) suggest some possible biogeochemical cycling at the sediment-water inerface. The deposition of Fe, Al, and Pb is predominantly associated with detrital material and occurs mainly during winter.
AN: 0791506
185 of 369
TI: (Vertical distribution of metals in marine particles in the western Mediterranean Sea: Role of biogeochemical processes.).
OT: La distribution verticale des metaux dans les particules marines en Mediterranee Occidentale: Role de processus biogeochimiques
AU: Risler,-N.; Lambert,-C.E.; Buat-Menard,-P.; Chesselet,-R.
AF: Cent. Faibles Radioact., Lab. Mixte CNRS-CEA, Gif-sur-Yvette, France
CO: 10. Reunion Annuelle des Sciences de la Terre, Bordeaux (France), 2 Apr 1984
SO: TENTH-ANNUAL-MEETING-ON-EARTH-SCIENCES.-BORDEAUX.-2-6-APRIL-1984.. 10e-REUNION-ANNUELLE-DES-SCIENCES-DE-LA-TERRE.-BORDEAUX.-2-6-AVRIL-1984.- Institut-Geologie-Bassin-Aquitaine,-Talence-France;-S.G.F.,-Paris-France1984. vol. 10 p. 474
ST: RESUMES-COMMUN.-REUN.-ANNU.-SCI.-TERRE. vol. 10
NT: Summary only.
LA: French
ER: M (Marine)
AB: The behavior of elements, the role of living organisms (Fe, Mn, Co, Zn) and the sources, atmosphere and continental slopes, has been studied in the Western Mediterranean. Results are: the euphotic zone is influenced by living organisms and atmospheric input; between 100 and 500 m is the zone of utilization of organic detritus where Fe, Co, Mn are recycled; in deep waters, vertical distributions are more uniform, and result from the combined effect of absorption-desorption processes and the bursting of faecal pellets; near the bottom, a resuspension of the clay fraction occurs.
AN: 0791390
186 of 369
TI: Dynamic patterns of dissolved nitrogen in the Southern Bight of the North Sea.
AU: Baeyens,-W.; Mommaerts,-J.-P.; Dehairs,-L.G.F.
AF: Lab. Anal. Scheikd., Vrije Univ., Brussels, Belgium
SO: ESTUAR.-COAST.-SHELF.-SCI. 1984. vol. 18, no. 5, pp. 499-510
LA: English
ER: M (Marine)
AB: Spatial and temporal variations of dissolved inorganic nitrogen (DIN) have been assessed in onshore and offshore areas of the Southern Bight on the basis of several years' measurements. They indicate that both the residual flow lines and DIN isoconcentration lines run parallel with the coast excpt in the vicinity of imporant freshwater discharge points such as the Scheldt estuary. Evidence was found that the seasonal DIN oscillations are not created through fluctuations in input conditions at the lateral boundaries, despite considerable fluctuations in these inputs which include the English Channel and also rivers such as the Scheldt estuary. In both the onshore and offshore areas the sum of daylight phytoplanktonic nitrogen intake and sediment release of nitrogen corresponds to the observed DIN variations during most of the year.
AN: 0780807
187 of 369
TI: Denitrification rates and availability of organic matter in marine environments.
AU: Liu,-K.-K.; Kaplan,-I.R.
AF: Inst. Geophys. and Planet. Phys., Univ. California, Los Angeles, CA 90024, USA
SO: EARTH-PLANET.-SCI.-LETT. 1984. vol. 68, no. 1, pp. 88-100
LA: English
ER: M (Marine)
AB: Relationships between denitrification rates and availability of organic matter in three types of marine environments - water column, water-sediment interface and sediments - were delineated. Correlation between supply and demand of organic matter for denitrificaiton in the first two types of environments suggests that denitrifation is mainly supported by organic matter provided as macroparticles from the euphotic zone. Decomposition of organic matter during denitrification in the water column of certain high productivity areas is at a minimum 1/4 to 1/2 as effective as the respiratory processes which use dissolved oxygen.
AN: 0780669
188 of 369
TI: The microbial manganese cycle.
AU: Nealson,-K.H.
AF: Univ. California at San Diego, Scripps Inst. Oceanogr., MBRD, A-002, La Jolla, CA 92093, USA
SO: MICROBIAL-GEOCHEMISTRY. Krumbein,-W.E.-ed. 1983. pp. 191-221
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AN: 0758347
189 of 369
TI: The microbial silica cycle.
AU: Krumbein,-W.E.; Werner,-D.
AF: Geomicrobiol. Div., Univ. Oldenburg, D-2900 Oldenburg, FRG
SO: MICROBIAL-GEOCHEMISTRY. Krumbein,-W.E.-ed. 1983. pp. 125-157
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AN: 0758331
190 of 369
TI: The microbial sulphur cycle.
AU: Joergensen,-B.B.
AF: Inst. Ecol. and Genet., Univ. Aarhus, Ny, Munkegarde, DK-8000 Aarhus C, Denmark
SO: MICROBIAL-GEOCHEMISTRY. Krumbein,-W.E.-ed. 1983. pp. 91-124
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AN: 0758328
191 of 369
TI: Microbial geochemistry.
AU: Krumbein,-W.E.-(ed.)
SO: OXFORD-UK-BLACKWELL-SCIENTIFIC-PUBLICATIONS 1983. 342 pp
NT: Price: $60.00.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AN: 0757958
192 of 369
TI: A nonlinear model of the carbon cycle in the ocean.
AU: Kagan,-B.A.; Ryabchenko,-V.A.
AF: Leningrad Dep., Inst. Oceanol., USSR Acad. Sci., Leningrad, USSR
SO: DOKL.-EARTH-SCI.-SECT. 1981. vol. 258, no. 1-6, pp. 208-211
LA: English
ER: M (Marine)
AB: A model of the carbon cycle in the ocean that would be an adequate representation of reality should describe the interrelated variations of the temperature, total carbon content, the decomposition and production of organic matter that are the source and sink for organic carbon, the behavior of CO sub(2) in solution, gas exchange with the atmosphere, the thickness of the upper quasihomogeneous layer (UQL), exchange processes between the UQL and the deep layer (DL), as well as between the regions of generation of cold deep water and the rest of the ocean. Existing models do not satisfy this requirement. Their deficiencies are overcome to some degree in the model discussed below.
AN: 0743939
193 of 369
TI: Role of marine phytoplankton in determining the chemical speciation and biogeochemical cycling of arsenic.
AU: Sanders,-J.G.
AF: Univ. Maryland, Solomons, MD, USA
CO: 6. Biennial International Estuarine Research Conference, Gleneden Beach, OR (USA), 1-5 Nov 1981
SO: ESTUARIES. 1981. vol. 4, no. 3, p. 283
NT: Summary only.
LA: English
ER: B (Brackish)
AB: Phytoplankton take up arsenate readily via the phosphate transport system, incorporating a small percentage into the cell. The majority of the arsenic is released in reduced (as arsenite) and methylated (as monomethylarsonic and dimethylarsinic acids) form, causing substantial changes in arsenic speciation. Experiments performed in controlled marine ecosystems correlate well with field sampling; Results indicate that rates of arsenic reduction and methylation are proportional to the primary productivity of the ecosystem. In highly productive ecosystems, up to 80% of the total arsenic pool may undergo reduction and methylation. Large differences in the rate of arsenic uptake and incorporation exist within algal groups.
AN: 0712502
194 of 369
TI: Interactions of marine plankton with transuranic elements. 3. Biokinetics of americium in euphausiids.
AU: Fisher,-N.S.; Bjerregaard,-P.; Fowler,-S.W.
AF: Int. Lab. Mar. Radioact., Mus. Oceanogr., MC-98000 Monaco
SO: MAR.-BIOL. 1983. vol. 75, no. 2-3, pp. 261-268
LA: English
ER: M (Marine)
AB: In a series of laboratory experiments, the biokinetics of super(241)Am, an important transuranium element, was studied in Meganyctiphanes norvegica . The euphausiids accumulated Am from water by passive adsorption onto exoskeletons, achieving wet weight concentration factors on the order of 10 super(2) after 1 wk exposure; concentration factors varied inversely with the size of the euphausiids and linearly with their surface area:wet weight ratios. Essentially all (96 plus or minus 10%) of the Am taken up from water was associated with the exoskeleton, so that negligible Am was retained by the euphausiids after molting. The retention half-time of Am in molts was 2.9 d. Euphausiids could also concentrate Am from feeding suspensions by ingesting Am-labelled diatom cells. After passage through the gut, virtually all ( approximately equals 99%) of the ingested Am was defecated within 1 wk. The retention half time of Am in fecal pellets was 41 and 51 d at 13 degree and 5 degree C respectively.
AN: 0697443
195 of 369
TI: Polonium-210: Its relative enrichment in the hepatopancreas of marine invertebrates.
AU: Cherry,-R.D.; Hayraud,-M.; Higgo,-J.J.W.
AF: Mus. Oceanogr., Int. Lab. Mar. Radioact., Monaco
SO: MAR.-ECOL.-PROG.-SER.. 1983. vol. 13, no. 2-3, pp. 229-236
LA: English
ER: M (Marine)
AB: The alpha-radioactive nuclide super(210)Po is known to be enriched in many components of the marine biosphere. Particularly high concentrations of super(210)Po are found in the hepatopancreas of many marine invertebrates, making this organ one of the highest known natural radiation dose domains. Concentrations of many other elements in the hepatopancreas have been reported in the literature, and these are summarised and compared with those for super(210)Po. The enrichment factor concept is used, and a simple marine biogeochemical classification of the elements results. The enrichment factors for Ag. Cd and Se in the marine hepatopancreas are found to be even higher than that for super(210)Po; those for Cu, Hg, Sb and Zn are an order of magnitude lower, and those for all other elements for which data are available are at least one order of magnitude lower still.
AN: 0678619
196 of 369
TI: General discussion. Biogeochemical cycling.
AU: Furtado,-J.I.; Mori,-S.
SO: TASEK-BERA,-THE-ECOLOGY-OF-A-FRESHWATER-SWAMP. Furtado,-J.I.;Mori,-S.-eds. 1982. vol. 47 p. 359
ST: MONOGR.-BIOL. vol. 47
LA: English
ER: F (Freshwater)
AB: The macrophytes in the forested and non-forested littoral regions appear important in purifying the waters and being able to cope with organic loading. The capacity of the swamp-forest needs to be examined further as it has implications in pollution control.
AN: 0677246
197 of 369
TI: Cycling of toxic organics in the Great Lakes: A 3-Year status report.
AU: Eadie,-B.J.; Robbins,-J.A.; Landrum,-P.F.; Rice,-C.P.; Simmons,-M.S.
CA: NOAA, Ann Arbor, MI. Great Lakes Environmental Research Lab
SO: 1983. 176 pp
NT: NTIS Order No.: PB83-256792; NOAA-83090104.
RN: NOAA/TM/ERL/GLERL-45 (NOAATMERLGLERL45)
LA: English
ER: F (Freshwater)
AB: This interim 3-year status report describes the results of GLERL's studies on the cycling of toxic organics in the Great Lakes. A hierarchy of models has been developed. These modeling efforts have identified process research needs, some of which have been supported. Reported here are results of the authors' work on 1) air-water exchange; 2) photolysis; 3) sorption and partitioning; 4) particle settling and transport; 5) early diagenetic processes in lake sediments; 6) interaction of sediments, contaminants, and benthic organisms; and 7) simulation studies of organic contaminants.
AN: 0676973
198 of 369
TI: Balance of the biogenic calcium carbonate production in an oligotrophic lake (Lake Attersee, Salzkammergut - Austria).
OT: Bilanzierung der biogenen Karbonatproduktion eines oligotrophen Sees. (Attersee, Salzkammergut-Oesterreich)
AU: Schroeder,-H.G.; Windolp,-H.; Schneider,-J.
AF: Goldschmidtst. Geol.-Palaentol. Inst., und Mus., 3, 3400 Goettingen, FRG
SO: ARCH.-HYDROBIOL. 1983. vol. 97, no. 3, pp. 356-372
LA: German
ER: F (Freshwater)
AB: Biogenic carbonate precipitation has been determined quantitatively at Lake Attersee (Salzkammergut/Austria). Epilimnetic and benthic decalcification cause changes in water chemistry during 24 hours and also seasonal changes have been observed. Epilimnetic decalcification is dominant in the southern and central part of the lake while in the north benthic decalcification plays an important role in the shallow sublittoral areas. The whole biogenic calcium carbonate production reaches about 11,000 to 12,000 metric tons a year or 250 metric tons per km a year.
AN: 0655549
199 of 369
TI: Mathematical modelling of estuaries and coastal waters.
AU: James,-A.
AF: Dep. Civ. Eng., Univ. Newcastle-upon-Tyne, Newcastle-upon-Tyne, UK
CO: 11. Biennial Conference of the International Association on Water Pollution Research and Control, Cape Town (South Africa), 29 Mar-2 Apr 1982
SO: WATER-POLLUTION-RESEARCH-AND-CONTROL.-PART-4. Jenkins,-S.H.-ed. 1982. vol. 14, no. 8 pp. 1109-1123
ST: WATER-SCI.-TECHNOL. vol. 14, no. 8
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Mathematical modelling has contributed significantly to our ability to handle pollution problems in estuaries and coastal water. The complexities of the hydraulics and biogeochemical cycles precluded the use of simple empirical approaches which are satisfactory in rivers and lakes. Although physical modelling is an alternative not all the phenomena concerned may be simulated physically; there are problems of scaling and the cost is very high. In these circumstances mathematical models are an essential tool in the control of pollution. Estuaries and coastal waters are physically contiguous and share many hydraulic characteristics but there are important differences which have made the modelling approaches to the two environments fundamentally different.
AN: 0642233
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TI: Effect of the biogenic factor upon the sedimentation and bottom morphology in the Sea of Azov.
OT: Vliyanie biogennogo faktora na osadkonakoplenie i morfologiyu dna Azovskogo moryo
AU: Artyukhin,-Yu.V.; Grudinova,-L.Ya.; Marynich,-A.G.; Badenko,-A.E.
AF: Address not stated
SO: IZV.-VSES.-GEOGR.-O-VA. 1983. vol. 115, no. 2, pp. 149-154
LA: Russian
ER: M (Marine)
AB: A high productivity of zoobenthos is shown to affect bottom and coastal sedimentation in the Sea of Azov. Bottom mollusks affect bottom topography and sediment accumulation by assimilating carbonates from sea water to be transformed into solid shells. Common cockle Cardium edule to accelerate sedimentation rates considerably. In the areas of the "primary" and "secondary" biogenic matter discharge the sedimentation rate may reach 10-15 om per year.
AN: 0621721
201 of 369
TI: Uptake and conversion of selenium by a marine bacterium.
AU: Foda,-A.; Vandermeulen,-J.H.; Wrench,-J.J.
AF: Mar. Ecol. Lab., BIO, Dartmouth, N.S. B2Y 4A2, Canada
CO: Conference on Pollution in the North Atlantic Ocean, Halifax, N.S. (Canada), 19-23 Oct 1981
SO: CONFERENCE-ON-POLLUTION-IN-THE-NORTH-ATLANTIC-OCEAN. 1983. vol. 40, no. suppl.2 pp. 215-220
ST: CAN.-J.-FISH.-AQUAT.-SCI. vol. 40, no. suppl.2
LA: English
ER: M (Marine)
AB: Bio-conversion of Se was examined by incubating Pseudomonas marina in seawater containing either selenite (Na sub(2)Se super(IV)O sub(3)) or selenate (Na sub(2)Se super(VI)O sub(4)). At the concentrations of selenite and selenate used (10 super(-4)-10 super(-7) mol/L), the growth of P. marina was not inhibited. Under these conditions, selenite was taken up by P. marina , but selenate was not found to enter the cells. Pseudomonas marina incorporated selenite from filtered seawater into subcellular fractions, primarily protein (30-50%) and amino acids (44-70%). When incubated in marine broth, P. marina incorporated super(75)selenite primarily into protein (up to 75%), with a lesser amount into the amino acid fraction (approx. 25%). Insignificant amounts were associated with the bacterial lipid fraction. Se super(75) was found in the protein and amino acid fractions within 10 min of incubation in medium containing selenite.
AN: 0614339
202 of 369
TI: Role of marine phytoplankton in determining the chemical speciation and biogeochemical cycling of arsenic.
AU: Sanders,-J.G.
AF: Acad. Nat. Sci., Benedict Estuarine Res. Lab., Benedict, MD 20612, USA
CO: Conference on Pollution in the North Atlantic Ocean, Halifax, N.S. (Canada), 19-23 Oct 1981
SO: CONFERENCE-ON-POLLUTION-IN-THE-NORTH-ATLANTIC-OCEAN. 1983. vol. 40, no. suppl.2 pp. 192-196
ST: CAN.-J.-FISH.-AQUAT.-SCI. vol. 40, no. suppl.2
LA: English
ER: M (Marine)
AB: Biological mediation of arsenic speciation in marine systems is substantial and significant. Phytoplankton reduce and methylate arsenic, thus altering its geochemical cycle. Rates of arsenic reduction and methylation are proportional to the primary productivity of the ecosystem. In highly productive ecosystems, up to 80% of the total arsenic pool may undergo reduction and methylation. Experiments detailing rates of reduction have been performed in controlled marine ecosystems. Predictions of arsenic speciation based on these results agree well with actual samples taken from coastal areas. The form of reduced arsenic present varies between regions and temporally within regions, probably because of differences in phytoplankton community structure.
AN: 0604705
203 of 369
TI: The role of zooplankton in the accumulation and deposition of DuPont Edgemoor waste (an acid-iron waste) at a deepwater dumpsite in the Northwest Atlantic.
AU: Capuzzo,-J.M.
AF: Woods Hole Oceanographic Inst., Woods Hole, MA 02543, USA
CO: Conference on Pollution in the North Atlantic Ocean, Halifax, N.S. (Canada), 19-23 Oct 1981
SO: CONFERENCE-ON-POLLUTION-IN-THE-NORTH-ATLANTIC-OCEAN. 1983. vol. 40, no. suppl.2 pp. 242-247
ST: CAN.-J.-FISH.-AQUAT.-SCI. vol. 40, no. suppl.2
LA: English
ER: B (Brackish)
AB: DuPont Edgemoor waste derived from titanium dioxide production is a highly acidic solution of ferric chloride containing relatively high levels of several trace metals including Cr, V, Pb, Ni, Cu, and Cd. Approximately 3 x 10 super(5) t multiplied by yr super(-1) are dumped at Deepwater Dumpsite 106, similar to 160 km southeast of Ambrose Light, New York. Chemical dispersion studies at the dumpsite indicate that ferric oxide precipitates in the waste plume and that other trace metals may become associated with this particulate phase. Ingestion of this particulate phase by copepods is a significant route of uptake for the waste-derived metals in the laboratory. Accumulation of the various metals by exposed copepods ranged from 10.8% above control values for Fe to 54.7% for Cu. The ratios of the various trace metals relative to Fe were only slightly enhanced in exposed copepods in comparison with control copepods but 1 to 2 orders of magnitude higher than the metal ratios of a 20 super(5) waste dilution.
AN: 0604636
204 of 369
TI: Uptake and conversion of selenium by a marine bacterium.
AU: Foda,-A.; Vandermeulen,-J.H.; Wrench,-J.J.
AF: Marine Ecol. Lab., BIO, Dartmouth, N.S. B2Y 4A2, Canada
CO: Conference on Pollution in the North Atlantic Ocean, Halifax, N.S. (Canada), 19-23 Oct 1981
SO: CONFERENCE-ON-POLLUTION-IN-THE-NORTH-ATLANTIC-OCEAN. 1983. vol. 40, no. suppl.2 pp. 215-220
ST: CAN.-J.-FISH.-AQUAT.-SCI. vol. 40, no. suppl.2
LA: English
ER: M (Marine)
AB: Bio-conversion of Se was examined by incubating Pseudomonas marina in seawater containing either selenite (Na sub(2)Se super(IV)O sub(3)) or selenate (Na sub(2)Se super(VIO)d4). At the concentrations of selenite and selenate used (10 super(-4) - 10 super(-7) mol/L), the growth of P. marina was not inhibited. Under these conditions, selenite was taken up by P. marina , but selenite was not found to enter the cells. Pseudomonas marina incorporated selenite from filtered seawater into sub-cellular fractions, primarily protein (30-50%) and amino acids (44-70%). When incubated in marine broth, P. marina incorporated super(75)selenite primarily into protein (up to 75%), with a lesser amount into the amino acid fraction (approximately 25%). Insignificant amounts were associated with the bacterial lipid fraction. Se super(IV) was found in the protein and amino acid fractions within 10 min of incubation in medium containing selenite.
AN: 0604520
205 of 369
TI: Session 2 --- summary and overview: Heavy metals.
AU: Farrington,-J.W.; Vandermeulen,-J.H.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: Conference on Pollution in the North Atlantic Ocean, Halifax, N.S. (Canada), 19-23 Oct 1981
SO: CONFERENCE-ON-POLLUTION-IN-THE-NORTH-ATLANTIC-OCEAN. 1983. vol. 40, no. suppl.2 pp. 221-225
ST: CAN.-J.-FISH.-AQUAT.-SCI. vol. 40, no. suppl.2
LA: English
ER: M (Marine)
AB: A wide variety of papers were presented at this conference on marine pollution on the subject of trace metal studies, the problem of contamination in sampling and in the precision and accuracy of analyses, notably the analyses of seawater. Despite the progress in sampling and analyses, standardization of basic data still requires more attention via the use of standard reference materials and intercalibration exercises.
AN: 0604511
206 of 369
TI: Trace metal remobilization in the interstitial waters of red clay and hemipelagic marine sediments.
AU: Sawlan,-J.J.; Murray,-J.W.
AF: Mobil Explor. and Prod. Serv. Inc., P.O. Box 900, Dallas, TX 75221, USA
SO: EARTH-PLANET.-SCI.-LETT. 1983. vol. 64, no. 2, pp. 213-230
LA: English
ER: M (Marine)
AB: Interstitial water samples from the Guatemala Basin and the coast of Baja California have been analyzed for manganese, iron, copper, nickel and nitrate. The data provide a systematic look at changes in trace metal diagenesis proceeding from red clay to highly reducing nearshore sediments. In red clay sediments, the nitrate concentrations suggest that only aerobic respiration is occurring. Manganese and iron are below detection. Nickel concentrations remain the same as in bottom seawater but copper shows a pronounced maximum just at the sediment/water interface. Proceeding to hemipelagic sediments, denitification becomes increasingly important and manganese and iron remobilization occur in the sediments. The linear manganese and nitrate profiles suggest regions of production or consumption separated by zones of diffusion. This differs from the conventional picture of a continuous series of reactions within the sediments. Manganese reduction always occurs before iron reduction.
AN: 0603895
207 of 369
TI: Deep circulation of the North Atlantic over the last 200,000 years: Geochemical evidence.
AU: Boyle,-E.A.; Keigwin,-L.D.
AF: Dep. Earth and Planet. Sci., Massachusetts Inst. Technol., Cambridge, MA 02139, USA
SO: SCIENCE-WASH.. 1982. vol. 218, no. 4574, pp. 784-787
LA: English
ER: M (Marine)
AB: Variations in the cadmium/calcium ratio of North Atlantic Deep Water are recorded in the fossil shells of benthic foraminifera. The oceanic distribution of cadmium is similar to that of the nutrients, hence the cadmium/calcium ratio in shells records temporal variations in nutrient distributions. Data from a North Atlantic sediment core show that over the past 200,000 years there has been a continuous supply of nutrient-depleted waters into the deep North Atlantic. The intensity of this source relative to nutrient-enriched southern waters diminished by about a factor of 2 during severe glaciations. This evidence combined with carbon isotope data indicates that the continental carbon inventory may have been less variable than previously suggested.
AN: 0589652
208 of 369
TI: Mass balance of carbon and phosphorus in Shark Bay, Western Australia.
AU: Smith,-S.V.; Atkinson,-M.J.
AF: Hawaii Inst. Mar. Biol., P.O. Box 1346, Kaneohe, HI 96744, USA
SO: LIMNOL.-OCEANOGR. 1983. vol. 28, no. 4, pp. 625-639
LA: English
ER: M (Marine)
AB: Deviations of total CO sub(2), total alkalinity, and reactive P from conservative evaporation lines are used to quantify nonconservative fluxes of these materials in a negative estuary; the fluxes are then partitioned among CaCO sub(3) production, net community organic carbon production, and CO sub(2) gas evasion. The rate of organic metabolism for the system is controlled by nutrient delivery, although individual communities within the system support higher local metabolic rates than the bay-wide average by exchange of materials between autotrophic and heterotrophic components. The three CO sub(2) flux processes act in concert to keep pH and PCo sub(2) relatively constant.
AN: 0586406
209 of 369
TI: Phosphorus dynamics in a woodland stream ecosystem: A study of nutrient spiralling.
AU: Newbold,-J.D.; Elwood,-J.W.; O'-Neill,-R.V.; Sheldon,-A.L.
AF: Stroud Water Res. Cent., Acad. Natl. Sci. Philadelphia, R.D. 1, Box 512, Avondale, PA 19311, USA
SO: ECOLOGY. 1983. vol. 64, no. 5, pp. 1249-1265
LA: English
ER: F (Freshwater)
AB: The term spiralling refers to the interdependent processes of cycling and downstream transport of nutrients in a stream ecosystem. To describe spiralling in Walker Branch, a first-order woodland stream in Tennessee, the authors released super(32)PO sub(4) to the stream water and measured its uptake from the water and then followed its dynamics in coarse particulate organic matter (CPOM), fine particulate organic matter (FPOM), aufwuchs, grazers, shredders, collectors, net-spinning filter feeders, and predators over a 6-wk period. Rates of transfer among compartments and rates of downstream transport were estimated by fitting a partial differential equation model of the ecosystem to the data. With the resulting coefficients, the model was run to steady state to estimate standing stocks and fluxes of exchangeable phosphorus.
AN: 0570766
210 of 369
TI: Organic matter transfer during diurnal vertical migrations of pelagic animals in the tropical oceanic areas.
OT: Perenos organicheskogo veshchestva pri sutochnykh vertikal'nykh migratsiyakh pelagicheskikh zhivotnykh v tropicheskikh rajonakh okeana
AU: Tsejtlin,-V.B.
AF: Inst. Okeanol. AN S.S.S.R, Moscow, USSR
SO: OKEANOLOGIYA. 1982. vol. 22, no. 5, pp. 827-832
LA: Russian
ER: M (Marine)
AB: Organic matter can be transfered to deeper layers in the bodies or with excretions of migrating animals. In the first case the transfer is determined as a difference between the consumption of migrants by predators at the lowest depth of occurrence and the proportion of their own diet consumed at this depth. It is shown that even insignificant feeding at the lower depth results in a very small or zero organic matter transfer. In the second case the organic matter can transfered with the excretions of macroplanktonic animals only and it constitutes a very small proportion in the detritus supply from the upper layers.
AN: 0569438
211 of 369
TI: Biogeochemical approach to the study of the World Ocean pollution.
AU: Morozov,-N.P.
AF: VNIRO, Moscow, USSR
CA: International Counc. for the Exploration of the Sea, Copenhagen (Denmark)
CO: Council Meeting, 1982, of the International Council for the Exploration of the Sea (Copenhagen (Denmark)) (11 Oct 1982)
SO: COPENHAGEN-DENMARK-ICES 1982. 13 pp
ST: ICES-COUNCIL-MEETING-1982-COLLECTED-PAPERS.
RN: ICES-CM-1982/E:21 (ICESCM1982E21)
LA: English
ER: M (Marine)
AN: 0567368
212 of 369
TI: The importance of measuring microbial enzymatic functions while assessing and predicting long-term anthropogenic perturbations.
AU: Griffiths,-R.P.
AF: Dep. Microbiol., Oregon State Univ., Corvalis, OR 97331, USA
SO: MAR.-POLLUT.-BULL. 1983. vol. 14, no. 5, pp. 162-165
LA: English
ER: M (Marine)
AB: The studies outlined were an attempt to quantify the impact of a pollutant (crude oil) on the microbial activities associated with major nutrient cycling in arctic and subarctic sediments. In addition, an assessment was made concerning the potential impact of this pollutant in a prospective lease area for offshore drilling. The general approach taken and a brief summary of the results are described to illustrate the feasibility of this approach in application to other pollution impact studies.
AN: 0565853
213 of 369
TI: Modeling in estuaries and coastal lagoons.
OT: L'utilisation de modeles dans l'etude des estuaires et des lagunes cotiers
AU: Nixon,-S.W.
AF: Univ. Rhode Island, Kingston, RI, USA
CO: Workshop on the Coastal Ecosystems of West Africa, Dakar (Senegal), 11 Jun 1979
SO: THE-COASTAL-ECOSYSTEMS-OF-WEST-AFRICA:-COASTAL-LAGOONS,-ESTUARIES-AND-MANGROVES.-A-WORKSHOP-REPORT,-DAKAR,-11-15-JUNE-1979. LES-ECOSYSTEMES-COTIERS-DE-L'-AFRIQUE-DE-L'-OUEST:-LAGUNES,-ESTUAIRES-ET-MANGROVES.-RAPPORT-D'-UN-ATELIER,-DAKAR,-11-15-JUIN-1979.- UNESCO-Div.-of-Marine-Sciences,-Paris-France1981. no. 17 p. 57
ST: UNESCO-REP.-MAR.-SCI.-RAPP.-UNESCO-SCI.-MER. no. 17
NT: Fr. ed. pp. 55-56.
LA: English
ER: M (Marine); B (Brackish)
AB: There are 3 major types of models of use to study the ecology of estuaries and lagoons. One is the standard statistical model, such as the multivariate repression models used in fisheries work. While these are often quite useful and require a relatively small data input, they are not very applicable to ecosystems analysis. For systems analysis a more mechanistic sort of model is meeded in which a mathematical synthesis of a great deal of reductionist data can be obtained. Such models may have stochastic as well as deterministic formulations and provide a holistic point of view for exploring the consequences of a great deal of "autecological" or physiological research on individual species. For experimental problems concerning the probable response of natural ecosystems to perturbations, living models or microcosms should be developed as small scale analogues of larger nature. It is possible to maintain complex marine systems in replicate containers for long periods to study the biological effects of various pollutants as well as biomagnification, inter- and intra-species interactions, and biogeochemical cycling of the pollutant.
AN: 0554836
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TI: A layer-by-layer analysis of seasonal and long-term dynamics of phosphorus in the Baltic Sea, using the data on the Gotland Deep as an example.
AU: Yurkovskiy,-A.K.; Khozioskiy,-S.A.
AF: Address not stated
SO: OCEANOL.-ACAD.-SCI.-USSR. 1982. vol. 22, no. 4, pp. 429-433
LA: English
ER: M (Marine)
AB: The main points of phosphorus dynamics in the Baltic Sea are examined. The long-term pattern of phosphorus exchange between the water column and the bottom sediments in the Gotland Deep is discussed. It is shown that a large increase in phosphorus concentration in deep water, weakening of the halocline and stratification of the upper layer in summer have contributed to a gradual shift of the P metabolic cycle of the phosphorus to a new quantitative level, thereby promoting eutrophication of the sea. The vertical distribution and seasonal phosphorus cycles are approximated by polynomial expressions written in terms of sppt, O sub(2), H sub(2)S concentrations, 1 degree C chlorophyll a content, and annual runoff of nutrients from land. A biogeochemical mechanism for the eutrophying effect of phosphorus in the central Baltic Sea is outlined.
AN: 0550446
215 of 369
TI: Bacterial biomass and productivity in sediments, stromatolites, and water of Hamelin Pool, Shark Bay, Western Australia.
AU: Moriarty,-D.J.W.
AF: Div. Fish. Res., CSIRO Mar. Lab., Cleveland, Queensl. 4163, Australia
SO: GEOMICROBIOL.-J. 1983. vol. 3, no. 2, pp. 121-133
LA: English
ER: M (Marine)
AB: Heterotrophic bacterial biomass and growth rates were examined in stromatolites formed from four different types of benthic cyanobacteria. Pustular mat, which occurs in the upper intertidal zone, contained relatively few bacteria in the surface layers (0-5 mm), having about 0.2 x 10 super(6) cells mm super(-3), or 20 mgC m super(-2) per millimetre depth. Other mats in the lower intertidal and subtidal zones had from 1 x 10 super(6) cells mm super(-3) to 8 x 10 super(6) cells mm super(-3). Heterotrophic bacterial productivities were 2.1 to 5.0 mgC m super(-2) h super(-1). Turnover times were an average of 1 day in the sandy sediment and 5 days in the colloform mat. Although these results are minimum estimates, they indicate that heterotrophic bacteria contribute substantially to the carbon cycle in stromatolites, by utilizing about 20 to 30% of primary production.
AN: 0541739
216 of 369
TI: The geochemistry of plutonium in fresh and marine water environments.
AU: Sholkovitz,-E.R.
AF: Address not stated
SO: EARTH-SCI.-REV. 1983. vol. 19, no. 2, pp. 95-161
LA: English
ER: M (Marine); F (Freshwater)
AB: The chemical behaviour of plutonium in the hydrosphere is a subject of both great practical and intrinsic importance. The production and eventual disposal of Pu and other artificial radionuclides dictates that this be the case. The main objective of this paper is to provide a synthesis and critical examination of currently published data and interpretations of the geochemistry of Pu in natural waters and sediments. Where appropriate, an attempt is made to reinterpret published data with the aim of establishing the relationships between geochemical and biological processes and the distribution, concentration and speciation of Pu. Particular attention is paid to the question of the potential for the chemical remobilization of Pu from the solid to the aqueous phase. Approximately one third of the text deals with freshwater (mostly lakes) while two thirds discusses the estuarine, coastal and open ocean environments.
AN: 0535236
217 of 369
TI: The review of the health of the oceans.
CA: Joint Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP)
SO: REP.-STUD.-GESAMP. PARIS-FRANCE-UNESCO 1982. no. 15, 108 pp
NT: Also as: UNEP Reg. Seas Rep. Stud. No. 16. Incl. Glossary: 33 terms. 50 ref.
LA: English
ER: M (Marine); B (Brackish)
AB: This report assesses the condition of the marine environment ten year s after the United Nations Conference on Human Environment, Stockholm 1972. The aim of the report is to evaluate the conditions and qualit y of the marine environment in relation to man's various uses of the ocean. The report is divided into the following main sections: 1) bas ic properties of the ocean system; 2) biogeochemical cycles: 3) pollu tants in the marine environment; 4) uses of the marine environment in relation to pollution; 5) specific problems of regional significance ; 6) methodology for the assessment and control of marine pollution. The report is addressed to scientific administrators and decision mak ers concerned with the state of the marine environment and its protection.
AN: 0534928
218 of 369
TI: Perspectives on the importance of the oceanic particulate flux in the global carbon cycle.
AU: Peterson,-B.J.
AF: Exosystems Cent., Mar. Biol. Lab., Woods Hole, MA 02543, USA
SO: OCEAN-SCI.-ENG. 1981. vol. 6, no. 1, pp. 71-108
LA: English
ER: M (Marine)
AB: The atmospheric CO sub(2) concentration is increasing in part in response to combustion of fossil fuels. The author examines the hypothesis that "the sedimentation of plankton into the deep-sea and into coastal sediments may provide a sink for carbon that would help resolve this apparent discrepancy in the global carbon balance". The resulting calculations suggest that the "baseline" rate of particulate carbon sinking out of the surface ocean mixed layer is 2-3 billion metric tons (BMT) C per year. However, the recent increment in this flux due to nitrogen and phosphorus loading resulting from human activities is not likely to be greater than 0.1-0.2 BMT/year. The discrepancy between the estimated CO sub(2) sources and sinks in the global balances is several BMT/year. Thus, the hypothesis is rejected and the author guestions either or both (1) the terrestrial carbon balance calculations and (2) the oceanic CO sub(2) uptake and mixing models.
AN: 0505144
219 of 369
TI: Inorganic controls on the biogeochemical cycling of the elements in the oceans.
AU: Turner,-D.R.; Whitfield,-M.
AF: Mar. Biol. Assoc. UK, Citadel Hill, Plymouth PL1 2PB, UK
CO: 5. International Symposium on Environmental Biogeochemistry, Stockholm (Sweden), 1-5 Jun 1981
SO: ENVIRONMENTAL-BIOGEOCHEMISTRY. Hallberg,-R.-ed. 1983. vol. 35 pp. 9-37
ST: ECOL.-BULL. vol. 35
LA: English
ER: M (Marine)
AB: The geochemical cycling of an element through the seawater reservoir can be characterised on a global scale by its residence time in seawater (t@u- sub(y)) and by the ratio of its concentrations in seawater and crustal rock, the partition coefficient (K sub(y)(CR)). These parameters summarise the chemical reactivity of the elements in seawater and hence encompass the influence of a variety of chemical processes, some of which may be biologically mediated. In recent years considerable effort has been devoted to identifying elemental parameters suitable for this task, employing both theoretical and empirical approaches. Parameters proposed include electrostatic properties (ionic potential Z sub(i)/r sub(i) and ionic electrostatic energy Z super(2)@)di/r sub(i)), more empirical parameters which take account of covalency (electronegativity chi and "softness" parameters) and a screening loss parameter R sub( xi ) derived from Slater atomic orbitals. The use of such parameters can be shown to provide (1) some rationalisation of the observed K sub(y)(CR) and t@)u- sub(y) values, (2) a useful summary of the speciation of the elements in natural waters and (3) a concise means of classifying the biological functions of the elements.
AN: 0501412
220 of 369
TI: Environmental biogeochemistry.
AU: Hallberg,-R.-(ed.)
CO: 5. International Symposium on Environmental Biogeochemistry, Stockholm (Sweden), 1-5 Jun 1981
SO: ECOL.-BULL. 1983. vol. 36, 576 pp
LA: English
ER: M (Marine)
AB: This volume is based on papers presented at the 5th International Symposium on Environmental Biogeochemistry, held in Stockholm, Sweden, during July 1-5, 1981. On two session days the subjects pertained to the biogeochemical cycles of natural reservoirs. The presentations focused on reservoir component pool-size variability, chemical transformation mechanisms, and the impact of these factors on the interpretation of field data. On a third session day the topics related to the effects of man-made emissions on the biosphere. The final day of the symposium was reserved for a case-study of the Baltic Sea.
AN: 0501382
221 of 369
TI: The flux of carbon, nitrogen and phosphorus between coastal lagoons and offshore waters.
AU: Nixon,-S.W.; Lee,-V.
AF: Grad. Sch. of Oceanogr., Univ. Rhode Island, Kingston, RI 02881, USA
CO: Seminar on Coastal Lagoon Research, Present and Future, Beaufort, NC (USA), 29 Aug 1978
SO: COASTAL-LAGOON-RESEARCH,-PRESENT-AND-FUTURE.-PROCEEDINGS-OF-A-SEMINAR,-DUKE-UNIVERSITY-MARINE-LABORATORY,-BEAUFORT,-NC,-U.S.A.,-AUGUST-1978-UNESCO,-IABO. UNESCO,-Paris-France;-Int.-Assoc.-of-Biol.-Oceanogr.,-Paris-France PARIS-FRANCE-UNESCO 1981. no. 33 pp. 325-348
ST: UNESCO-TECH.-PAP.-MAR.-SCI. no. 33
LA: English
ER: B (Brackish)
AB: Data on the concentrations of a variety of ecologically important materials in Green Hill Pond, Charlestown, Rhode Island, USA, are presented in order to make a preliminary estimate of the magnitude and direction of the flux between this lagoon complex and Block Island Sound. The net fluxes of carbon, nitrogen and phosphate were estimated.
AN: 0477263
222 of 369
TI: Nickel, copper, cadmium and zinc in the Northwest Atlantic Ocean.
AU: Yeats,-P.A.; Campbell,-J.A.
AF: Atl. Oceanogr. Lab., Bedford Inst. Oceanogr., P.O. Box 1006, Dartmouth, N.S., Canada
SO: MAR.-CHEM. 1983. vol. 12, no. 1, pp. 43-58
LA: English
ER: M (Marine)
AB: The concentrations of nickel, copper, zinc and cadmium have been determined in the water of the northwest Atlantic Ocean between 45 degree and 60 degree N. The vertical distributions of Ni, Zn and Cd show depletion in surface waters and a general correlation with nutrients indicative of biogeochemical cycling of these metals. The profiles are complicated by the effects of other processes such as advection and aeolian inputs. At one station close to the Gibbs Fracture Zone, maxima in the nickel and copper concentrations are observed. This feature centered at 3200m is deeper than the core of the Gibbs Fracture Zone Water. Elevated near-bottom concentrations are observed for cadmium, but not copper.
AN: 0472619
223 of 369
TI: Initial effects of the Mount St. Helens eruption on nitrogen cycle and related chemical processes in Ryan Lake.
AU: Dahm,-C.N.; Baross,-J.A.; Ward,-A.K.; Lilley,-M.D.; Sedell,-R.
AF: Dep. Fish. & Wildlife, Oregon State Univ., Corvallis, OR 97331, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1983. vol. 45, no. 5, pp. 1633-1645
LA: English
ER: F (Freshwater)
AB: Ryan Lake, a 1.6-hectare basin lake near the periphery of the tree blowdown area in the blast zone 19 km north of Mount St. Helens, was studied from August to October 1980 to determine the microbial and chemical response of the lake to the eruption. Nutrient enrichment through the addition of fresh volcanic material and the organic debris from the surrounding conifer forest stimulated intense microbial activity. Concentrations of such nutrients as phosphorus, sulfur, manganese, iron, and dissolved organic carbon were markedly elevated. Nitrogen cycle activity was especially important to the lake ecosystem in regulating biogeochemical cycling owing to the limiting abundance of nitrogen compounds. Nitrogen fixation, both aerobic and anaerobic, was active from aerobic benthic and planktonic cyanobacteria. A general scenario for the microbial cycling of nitrogen, carbon, sulfur, and metals is presented for volcanically impacted lakes. The important role of nitrogen as these lakes recover from the cataclysmic eruption and proceed back towards their prior status as oligotrophic alpine lakes is emphasized.
AN: 0459374
224 of 369
TI: Benthic response to sedimentation of a spring phytoplankton bloom: Process and budget.
AU: Graf,-G.; Bengtsson,-W.; Diesner,-U.; Schulz,-R.; Theede,-H.
AF: Univ., Sonderforschungsbereich 95, Olhausenst. 40/60, D-2300 Kiel 1, FRG
SO: MAR.-BIOL. 1982. vol. 67, no. 2, pp. 201-208
LA: English
ER: M (Marine)
AB: The response of benthos to sedimentation of the spring phytoplankton bloom in the Kiel Bight (Western Baltic Sea) is described in terms of biomass (ATP) and activity (heat production and ETS-activity). Input of the bloom (11.5 g C m super(-2)) over a period from March 25 to April 19, 1980 to the sediment surface was in the form of cells and fresh phytodetritus as indicated by low C/N ratios ( less than or equal to 7) and high energy charge values (0.78). Benthic microbial activity was immediately stimulated by this input as heat production doubled and the activity of ETS tripled over winter values within 12 d in the absence of a significant increase in ambient temperature. A comparison of the two activity parameters suggests that anaerobic metabolism is more important during the winter (February and March) than after input of the bloom. Preliminary estimations for an annual budget suggest that the vertical transport of particulate organic matter via sedimentation can only explain 25% (15%) of the benthic activity in the shallow water ecosystem of the Kiel Bight. This indicates the presence of other sources of organic carbon such as benthic primary production or other transport processes providing carbon to the sediments.
AN: 0442935
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TI: Manganese cycling in northeast Pacific equatorial waters.
AU: Martin,-J.H.; Knauer,-G.A.
AF: Moss Landing Mar. Lab., P.O. Box 223, Moss Landing, CA 95039, USA
SO: J.-MAR.-RES. 1982. vol. 40, no. 4, pp. 1213-1225
LA: English
ER: M (Marine)
AB: Sea water samples collected above, within and below a pronounced oxygen minimum (0-5 mu mol liter super(-1)) were analyzed for their Mn content. Amounts of dissolved Mn slowly decreased with depth and little, if any, relationship with oxygen was found. In contrast, suspended particulate Mn values increased markedly at the top of the oxygen minimum. Labile Mn fluxes, measured with particle interceptor traps at depths of 125, 275, 525 and 900 m slowly increased with depth from 270 at 125 m to 450 mu g Mn cm super(-2) 1000 yr super(-1) at 900 m. These rates are the same order of magnitude as those estimated for excess Mn accumulating in open-ocean sediments, which implies that biogenic transport is a major factor in the oceanic cycling of Mn.
AN: 0442052
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TI: The global troposphere: Biogeochemical cycles, chemistry, and remote sensing.
AU: Levine,-J.S.; Allario,-F.
AF: NASA Langley Res. Cent., Hampton, VA 23665, USA
SO: ENVIRON.-MONIT.-ASSESS. 1982. vol. 1, no. 3, pp. 263-306
LA: English
AB: The chemical composition of the troposphere is controlled by various biogeochemical cycles that couple the atmosphere with the oceans, the solid Earth and the biosphere, and by atmospheric photochemical/chemical reactions. These cycles and reactions are discussed and a number of key questions concerning tropospheric composition and chemistry for the carbon, nitrogen, oxygen and sulfur species are identified. Next, the authors review various remote sensing techniques and instruments capable of measuring and monitoring tropospheric species from the ground, aircraft and space to address some of these key questions. They also consider future thrusts in remote sensing of the troposphere.
AN: 0435522
227 of 369
TI: Analysis of vertical, seasonal and long-term dynamics of phosphorus in the Baltic Sea with special reference to the Gotland Deep.
OT: Analiz poslojnoj sezonnoj i mnogoletnej dinamiki fosfora v Baltijskom more na primere Gotlandskoj vpadiny
AU: Yurkovskij,-A.K.; Khozioskij,-S.A.
AF: BaltNIRKh, Riga, USSR
SO: OKEANOLOGIYA. 1982. vol. 22, no. 4, pp. 584-589
LA: Russian
ER: M (Marine)
AB: The dynamics of phosphorus in the Baltic Sea and long-term variations in exchange with the bottom are considered. A considerable increase in the amount of P in deep water, the weakening of the halocline and the summer stratification of the upper layer are shown to have gradually moved the metabolic cycle of P to a new quantitative level contributing to eutrophication of the sea. The vertical distribution and the seasonal cycles of P are approximated by polynomials relationships with S ppt., O sub(2), H sub(2)S, t degree C, chlorophyll and nutrient runoff from land. The biogeochemical mechanism of the eutrophicating effect of P in the central Baltic Sea is discussed.
AN: 0426582
228 of 369
TI: Heterotrophic bacteria associated with the degradation of zooplankton fecal pellets in Lake Michigan.
AU: Ferrante,-J.G.; Ptak,-D.J.
AF: Environmental Impact Stud. Div., Argonne Natl. Lab., IL 60439, USA
SO: J.-GREAT-LAKES-RES. 1978. vol. 4, no. 2, pp. 221-225
LA: English
ER: F (Freshwater)
AB: Heterotrophic microbes decompose most of the calanoid copepod fecal pellets produced in Lake Michigan before they reach the sediment. Rod-shaped nonfermenters isolated from copepod and Mysis relicta fecal pellets were identified as Pseudomonas maltophilia and Pseudomonas fluorescens species. No enterobacteriaceae or fungal hyphae were found on or in any pellets. This investigation suggests that Pseudomonas species are attached to and may degrade Mysis relicta and calanoid copepod fecal pellets in the water column of Lake Michigan.
AN: 0426532
229 of 369
TI: Dissolved and particulate hydrocarbons in water from a spring sampling of the Var River Estuary (S. France).
AU: Burns,-K.A.; Villeneuve,-J.-P.
AF: Int. Lab. Mar. Radioactivity, Int. Atomic Energy Agency, c/o Mus. Oceanogr., Monaco
CO: Workshop on the Chemistry and Analysis of Hydrocarbons in the Environment, Barcelona (Spain), Nov 1981
SO: TOXICOL.-ENVIRON.-CHEM. 1982. vol. 5, no. 3-4, pp. 195-203
LA: English
ER: M (Marine); B (Brackish)
AB: To address questions of water quality monitoring and to investigate processes controlling the biogeochemical cycling of organics in estuarine and marine systems, the authors have used a resin adsorption apparatus with in-line glass fiber filter for sampling "dissolved" and "particulate" organics. Analyses of water samples collected from the Var River and coastal Mediterranean show rivers are important sources of soluble pesticides and some PCB's. Petroleum products discharged to rivers and the sea surface plus atmospheric inputs of combustion products add to level of biogenic sources making distributions highly variable. The authors note an increase in relative importance in new unidentified halogenated hydrocarbon contaminants in coastal systems.
AN: 0425492
230 of 369
TI: The effect of hippopotamuses on potassium and phosphate ion concentrations in an African lake.
AU: Kilham,-P.
AF: Div. Biol. Sci., Univ. Michigan, Ann Arbor, MI 48109, USA
SO: AM.-MIDL.-NAT. 1982. vol. 108, no. 1, pp. 202-205
LA: English
ER: F (Freshwater)
AB: Anomalously high potassium:sodium and phosphate:sodium molar ratios are found in Hippo Pool (Uganda). These unusual ratios are consistent with the hypothesis that the leaching and partial decomposition of hippopotamus (Hippopotamus amphibius ) dung strongly affects the ionic composition of the water in this lake.
AN: 0413612
231 of 369
TI: Fate of corrosion products released from stainless steel in marine sediments and seawater. Part 1. Northeast Pacific pelagic red clay.
AU: Schmidt,-R.L.
CA: Battelle Pacific Northwest Labs., Richland, WA (USA)
SO: RICHLAND,-WA-USA-BPNL 1982. 45 pp
NT: NTIS Order No.: DE82012251. Contract AC06-76RL01830.
RN: PNL-3466-Pt.1 (PNL3466Pt1)
LA: English
ER: M (Marine)
AB: To provide information useful for determining the biogeochemical cycling of corrosion products in the benthic boundary layer of the deep ocean, neutron-activated stainless steel was exposed to seawater and to Northeast Pacific red clay under aerobic and non-oxygenated conditions. This report describes the trace metal geochemistry of the sediment and the chemical speciation of the corrosion products. The distribution of exp 60 Co released from the stainless steel exposed to aerated seawater show that almost 70% of exp 60 Co activity became associated with suspended particulate matter. No detectable exp 60 Co activity was present in the soluble, readily dissolved, or inorganic or weakly complexes fractions of aerated sediment which had been used to treat neutron-activated stainless steel. Almost 50% of the exp 60 Co activity was extracted in the combined soluble, easily dissolved, adsorbed, and organically complexed fractions from the non-oxgenated sediment treatment indicating that this much of the corrosion products may be initially released in ionic form.
AN: 0413432
232 of 369
TI: Volatile fatty acid cycling in organic-rich marine sediments.
AU: Sansone,-F.J.; Martens,-C.S.
AF: Dep. Oceanogr., Hawaii Inst. Geophys., Univ. Hawaii Manoa, Honolulu, HI 96822, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA. 1982. vol. 46, no. 9, pp. 1575-1589
LA: English
ER: M (Marine)
AB: Volatile fatty acid (VFA) apparent turnover rates were determined by measuring whole sediment VFA concentrations and the corresponding rea ction rate constants. The following ranges of VFA concentrations were measured in Cape Lookout Bight, N.C. sediments ( mu mole multiplied by l sub(s) super(-1)): acetate 54-660, propionate 1-24, butyrate <0.5-22, iso-butyrate <0.5 -6. Apparent turnover rates measured over a one-year period ranged fr om 18-600 mu mole multiplied by l sub(s) super(-1) multiplied by h super(-1) for acetate and 0.7-7 mu mole multiplied by l sub(s) super(-1) multiplied by h super(-1) for the carboxyl carbon of propionate. Methane production was observed only with acetate and only in sulfate depleted sediments; total acetate turnover attained approximately the same maximum value in both sulfate-reducing and sulfate-depleted sediments.
AN: 0413243
233 of 369
TI: Biogeochemical cycling in an organic-rich coastal marine basin--3. Dissolved gas transport in methane-saturated sediments.
AU: Kipphut,-G.W.; Martens,-C.S.
AF: Inst. Mar. Sci., Univ. North Carolina, Morehead City, NC 28557, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA. 1982. vol. 46, no. 11, pp. 2049-2060
LA: English
ER: M (Marine)
AB: The transport of dissolved gases in the anoxic sediments of Cape Lookout Bight, North Carolina, is controlled by diffusion and bubble ebullition and exhibits a distinct seasonal cycle. Detailed seasonal profiles of CH sub(4), N sub(2) and super(222)Rn and direct gas flux measurements indicate the ebullition dominates the flux of all dissolved gases across the sediment-water interface during summer months, and is of major importance on an annual basis. Transport within the upper 6-8 cm of sediment appears to be controlled by molecular diffusion of gases. Transport at greater depths is controlled by diffusion in winter and ebullition in summer. Rn-222 profiles were used to estimate the rate of stripping of dissolved gases within the CH sub(4) production zone (10-30 cm); rates averaged 3-5 percent per day and agreed with estimates derived from N sub(2) profiles. As a result of summer ebullition, the sediments of the bight are never at saturation with respect to the major gases present in seawater. Evidence from other sites suggests that ebullition may be an important transport process in many coastal sediments, and may provide mechanism for the transport of volatile reduced compounds between anoxic sediments and the atmosphere. super(222)Rn is a useful tracer for quantifying this transport.
AN: 0413220
234 of 369
TI: Cycling of xenobiotics through marine and estuarine sediments.
AU: D'-Asaro,-C.N.; Wilkes,-F.G.
AF: Univ. West Florida, Dep. Biol., Pensacola, FL, USA
CA: University of West Florida, Pensacola (USA). Dep. of Biology
SO: 1982. 51 pp
NT: NTIS Order No.: PB82-239252.
LA: English
ER: M (Marine); B (Brackish)
AB: The results of five broadly defined projects are reported. Cycling of xenobiotics was studied with a photobioassay system that used time-lapse photography to evaluate effects of Kepone and sodium pentachlorophenate on feeding activity of the lugworm, Arenicola cristata . Radio-labeled methyl parathion was used to demonstrate fate and effect in microcosms inhabited by lugworms. Uptake and depuration of chrysene by lugworms was evaluated in a flow-through system. A toxic sediment bioassay system was developed to provide a means to test effects of dredge spoil. Keponesorbed sediment and dredge spoil from James River and Houston Ship Channel were tested for 28 days. Long-term tests (100 days), with the same systems, were used to evaluate effects of a specific drilling mud from an an active exploratory platform. Predator-prey tests of sublethal effects of xenobiotics demonstrated effect in one-prey and two-prey systems. Evaluation of sublethal effects, such as avoidance of pollution gradients, was studied in a trough-type avoidance-response system. Tests with pinfish demonstrated that they will avoid chlorine-produced oxidants. Usefulness of small-scale microcosms was evaluated by developing methods to culture polychaetes and crustaceans. Various aspects of the biology of selected species were studied.
AN: 0413144
235 of 369
TI: Excretion of total phosphorus, dissolved reactive phosphorus, ammonia, and urea by Lake Michigan Mysis relicta .
AU: Madeira,-P.T.; Brooks,-A.S.; Seale,-D.B.
AF: Cent. Great Lakes Stud., Univ. Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
CA: Wisconsin Univ., Milwaukee, (USA). Sea Grant Inst.
SO: REP.-WIS.-UNIV.-SEA-GRANT-COLL.-PROGRAM. 1982. (10 pp)
NT: Reprinted from Hydrobiologia 93: 145-154, 1982.
RN: WIS-SG-82-736 (WISSG82736)
LA: English
ER: F (Freshwater)
AB: Rates of nutrient release by Mysis relicta in Lake Michigan were measured on five nights at a 45-m station near Milwaukee, Wisconsin, U.S.A., in the summer of 1977. Nocturnal vertical migrations of the mysids were monitored with both echosounder tracings and vertical net tows. Estimates of the total areal dry mass of the mysids ranged from 600 to 1,820 mg m super(-2). The depths of maximum mysid densities corresponded approximately with a deep phytoplankton peak located in the vicinity of the thermocline. Semiquantitative "demands" for N and P by phytoplankton within this peak were obtained from super(14)C estimates of primary production from a previous study, assuming a constant C:N:P ratio for the algae. These algal nutrient "demands" were compared to potential N and P release by the mysids to obtain a first approximation of the relative rates of nutrient supply and demand for the field phytoplankton populations. Analysis indicates that mysids may directly supply about 1-10% of the daily N and P "demands" of the phytoplankton in the deep peak. However, indirect interactions between Mysis relicta and other organisms, such as small zooplankton and fishes, could be major factors in nutrient recycling within the metalimnion and subthermocline region of Lake Michigan.
AN: 0410193
236 of 369
TI: (Organic matter of lagoon sediments (Etang de Berre). Carbohydrates as indicators of the origin and the evolution of the organic matter.).
OT: Matiere organique de sediments lagunaires (Etang de Berre). Etude des glucides en tant qu'indicateure de l'origine et de l'evolution de la matiere organique
AU: Delmas,-D.
CA: Marseille Univ. (France). Faculte des Sciences de Luminy
SO: LUMINY-FRANCE-UNIV.-MARSEILLE 1981. 107 pp
NT: These Doctorat 3e cycle - Oceanologie.
LA: French
ER: B (Brackish)
AB: This thesis deals with the organic matter carbohydrates in the sediments, their evolution during the driving in the soil and determination of marine or terrestrial origin of the organic substances especially in the Berre Lagoon. The qualitative and quantitative evolution is investigated and the biological or chemical mechanisms of accumulation and transformation are identified. At the sediment-water interface, the carbohydrates can be incorporated in some organo-metallic complexes, absorbed by the particulate matter, associated with other humic matter or combined with amines. Theses biochemical and geochemical reactions are analysed and the methodology is described.
AN: 0390482
237 of 369
TI: Geochemical functions of zooplankton at the stage of sedimentogenesis in the Sea of Azov.
OT: Geokhimicheskie funktsii zooplanktona na stadii sedimentogeneza v Azovskom more
AU: Khrustalev,-Yu.P.; Sevast'-yanova,-N.V.; Myrzoyan,-I.A.
AF: Gos. Univ., Rostov-na-Donu, USSR
SO: DOKL.-AN-S.S.S.R. 1982. vol. 264, no. 5, pp. 1239-1241
LA: Russian
ER: M (Marine)
AB: Active participation of pelagic organisms in the formation of geochemical characteristics of suspended sedimentary material in shallow inland seas and shelf zones is demonstrated. Zooplankton assimilates mineral components of the suspended matter removing from it vitally important chemical elements. This conclusion supported by experimental work is essential for understanding the geochemistry of sedimentation. The geochemical function of zooplankton includes transformation of the suspended form of elements into organic compounds, transport thereof to the bottom and enrichment of the water by dissolved forms during gradual desintegration of the skeletons.
AN: 0374997
238 of 369
TI: Remineralization and nutrient cycling in coastal marine ecosystems.
AU: Nixon,-S.W.
AF: Grad. Sch. Oceanogr., Univ. Rhode Island, Kingston, RI 02881, USA
CO: International Conference on the Effects of Nutrient Enrichment in Estuaries, Williamsburg, VA (USA), 29 May 1979
SO: ESTUARIES-AND-NUTRIENTS. Nielson,-B.J.;Cronin,-L.E.-eds. 1981. pp. 111-138
LA: English
ER: M (Marine); B (Brackish)
AB: Views of remineralization and nutrient cycling in coastal marine ecosystems have changed considerably over the last 30 years. The major trend has been an increasing appreciation for the complexity of processes involved, including some marked changes in our assessment of the importance of bacteria with respect to smaller animals and in our perception of the association between bacteria and particulate matter in the sea. Among the more recent developments in this area is a growing awareness of the importance of the coupling between benthic and pelagic communities in coastal waters. There appears to be a strong linear correlation between the organic matter produced in the overlaying water and the amount of organic matter consumed on the bottom in almost all of the coastal environments for which annual data are available.
AN: 0369027
239 of 369
TI: (Contribution of vegetation to heavy metal dynamics in a salt marsh in the north-east of the United States of America.).
OT: Contribution de la vegetation a la dynamique des metaux lourds dans un marais maritime du nord-est des Etats Unis d'Amerique
AU: Bourg,-A.
AF: Inst. Chimie, Univ. Berne, Freiestrass 3, 3 000 Berne 9, Switzerland
CO: 24. National Congress of the French Association of Limnology, Marseille (France), 28 May 1979
SO: FRENCH-ASSOCIATION-OF-LIMNOLOGY-24.-NATIONAL-CONGRESS,-MARSEILLE,-28-31-MAY-1979.. ASSOCIATION-FRANCAISE-DE-LIMNOLOGIE-24.-CONGRES-NATIONAL,-MARSEILLE,-28-31-MAI-1979.- Association-Francaise-de-Limnologie,-Paris-France1979. vol. 6, no. 3-4 pp. 205-210
ST: ANN.-UNIV.-PROVENCE-BIOL.-ECOL.-MEDITERR. vol. 6, no. 3-4
LA: French
ER: B (Brackish); F (Freshwater)
AB: The experimental addition of heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) on a Massachusetts salt marsh increases the exports of these metals outside of the marsh as detritus of the plant Spartina alterniflora (except for Fe). However, for the quantities added, it seems that, except for Mn, the exports are negligible (< 1%) compared to the additions.
AN: 0353440
240 of 369
TI: The Biogeochemical Cycle of Barium in the Open Ocean. An Evaluation.
AU: Dehairs,-F.
AF: Vrije Univ. Brussel, Lab. Analyt. Scheikd., Belgium
CA: International Counc. for the Exploration of the Sea, Copenhagen (Denmark)
CO: Council Meeting, 1980, of the International Council for the Exploration of the Sea, Copenhagen (Denmark), 6 Oct 1980
SO: COPENHAGEN-DENMARK-ICES 1980. 20 pp
ST: ICES-COUNCIL-MEETING-1980-COLLECTED-PAPERS.
RN: ICES-CM--1980/C:23 (ICESCM1980C23)
LA: English
ER: M (Marine)
AN: 0350618
241 of 369
TI: Nitrogen cycling in sea waters.
AU: Fogg,-G.E.
AF: Dep. Mar. Biol., University Coll. North Wales, Mar. Sci. Lab., Menai Bridge, Anglesey, Gwynedd LL59 5EH, UK
CO: The Nitrogen Cycle, London (UK), 17 Jun 1981
SO: PHILOS.-TRANS.-R.-SOC.-LONDON-SER.-B. 1982. vol. 296, no. 1082, pp. 511-520
LA: English
ER: M (Marine)
AB: An attempt to quantify the cycling of N in the oceans suggests that losses of combined N greatly exceed gains, a discrepancy that points to the inadequacy of our knowledge of the processes involved. Combined N in particulate matter sedimenting into deep water is partly returned to the euphotic zone in the form of nitrate, the rate of this upward flux of new nitrogen being the main determinant of the upper limit of biomass in any given area. Within the euphotic zone combined N is rapidly recycled by bacteria and animals and in oligotrophic areas the ammonium, urea, and perhaps organic, N that they make available is the main source maintaining phytoplankton growth.
AN: 0348767
242 of 369
TI: Phosphorus Solubilization by Some Marine Fungi.
AU: Araujo,-A.; D'-Souza,-J.; Karande,-A.A.
AF: Goa Coll. Pharm., Panaji, Goa-403 001, India
SO: MAHASAGAR. 1981. vol. 14, no. 1, pp. 67-70
LA: English
ER: M (Marine)
AB: Ten marine fungi were qualitatively screened for phosphorus solubilizing ability. The organisms were then tested quantitatively in liquid media containing tricalcium phosphate as a phosphorus source. The optimum pH for phosphorus solubilizing activity of fungi was from 6 to 6.5. An incubation period of 6 days was required for an appreciable quantity of phosphorus to be leached into the medium. A maximum amount of 18% phosphorus was obtained in the culture filtrate and about 54% phosphorus was found in the total cell mass with Penicillium funiculosum .
AN: 0348114
243 of 369
TI: (Organic Geochemistry of the Deep Marine Sediments. Orgon 4 , Aden Gulf, Oman Sea. November 1978.).
OT: Geochimie Organique des Sediments Marin Profonds. Orgon 4 . Golfe d'Aden, Mer d'Oman. November 1978
CA: CEPM-CNEXO, Comite d'Etudes Geochimiques Marines (France)
SO: PARIS-FRANCE-EDITIONS-DU-CENTRE-NATIONAL-DE-LA-RECHERCHE-SCIENTIFIQUE 1981. 547 pp
LA: French
ER: M (Marine)
AB: This report presents the results of the laboratory analysis undertaken by the scientific teams from the material collected during the Orgon 4 cruise in the Arabian Sea and Aden Gulf. 23 contributions describe the biological and biochemical aspects of the sedimentation and the organic geochemistry of the superficial and deep-sea marine sediments.
AN: 0337509
244 of 369
TI: Biogeochemistry and Geomicrobiology of Lagoons and Lagoonary Environments.
AU: Krumbein,-W.E.
CO: Seminar on Coastal Lagoon Research, Present and Future, Beaufort, NC (USA), 29 Aug 1978
SO: COASTAL-LAGOON-RESEARCH,-PRESENT-AND-FUTURE.-PROCEEDINGS-OF-A-SEMINAR.-DUKE-UNIVERSITY-MARINE-LABORATORY,-BEAUFORT,-NC,-U.S.A.,-AUGUST-1978-UNESCO,-IABO. UNESCO,-Paris-France;-Int.-Assoc.-of-Biol.-Oceanography,-Paris-France PARIS-FRANCE-UNESCO 1981. no. 33 pp. 97-109
ST: UNESCO-TECH.-PAP.-MAR.-SCI. no. 33
LA: English
ER: B (Brackish)
AB: In geochemical terms the lagoon is the centrepoint of 2 constantly changing and developing energy flows, one from the continent and one from the open sea. The biogeochemistry of lagoons can be described as the ephemeral upheaval of reduced organic compounds and speeding up of biochemcial reactions as a consequence of the constant exchange of lagoons with the open sea in cases of hypersaline systems and with the sea and continent in the case of brackish and freshwater lagoons. Productivity and nutrient cycles in lagoons is also discussed; it is believed future work on coastal lagoons should focus on : 1) plant adaptation to salt water; 2) biogeochemical cycles; 3) polluting influences from the mainland; and 4) comparative studies on tropical arid areas. Some findings from studies carried out on coastal lagoons along the Gulf of Aqaba in 1971-77 are presented.
AN: 0321516
245 of 369
TI: An Oxygen Model for Lake Haukivesi.
AU: Frisk,-T.
AF: Natl. Board of Waters, P.O. Box 250, 00101 Helsinki 10, Finland
CO: 30 Years Jubilee Symposium of the Finnish Limnological Society: Lakes and Water Management, Helsinki (Finland), 22-23 Sep 1980
SO: HYDROBIOLOGIA. 1982. vol. 86, no. 1-2, pp. 133-139
LA: English
ER: F (Freshwater)
AB: A simple water quality model for Lake Haukivesi, heavily loaded by pulp and paper mill effluents, has been developed. The main purpose of the model is to predict the concentration of dissolved oxygen in the hypolimnion. The lake is divided into seven sub-basins, and also into epilimnion and hypolimnion. Transfers between sub-basins are calculated using water balance equations. The state variables of the model are dissolved oxygen concentration, biochemical oxygen demand, phytoplankton biomass, and total phosphorus concentration. The effect of temperature on reaction rate coefficients has been taken into account. Temperature is calculated in the model using a second degree polynomial function. The processes affecting hypolimnetic oxygen consumption are BOD decay, decomposition of phytoplankton, benthic oxygen demand, and decomposition of slowly decaying organic matter.
AN: 0321499
246 of 369
TI: Joint FAO (GFCM)/UNEP Coordinated Project on Pollution in the Mediterranean. Report Number 2.
OT: Projet Commun Coordonne FAO (CGPM) PNUE sur la Pollution en Mediterranee. Rapport Numero 2
CA: FAO Gen. Fisheries Counc. for the Mediterranean, Rome, (Italy)
SO: CIRC.-CGPM. 1977. no. 6, 38 pp
LA: French
ER: M (Marine)
AB: The report contains results obtained from the 4 pilot projects carried out on pollution in the Mediterranean. The first 2 present data on the quantity of pollutants (heavy metals, chlorinated hydrocarbons) which accumulate in the bodies of the organisms occurring in the areas studied. The other 2 enable an understanding of the relations which exist between the levels of contaminants in the water and the organisms, a clarification of the biogeochemical cycle of the pollutants and the obtaining of data concerning not only the safety levels but also the effects of environmental factors on toxic reactions of the organisms.
AN: 0321399
247 of 369
TI: Sorption and Desorption of Trace Elements by Spartina alterniflora Detritus.
AU: Drifmeyer,-J.E.; Cross,-F.A.; Zieman,-J.C.
AF: Preventive Med. Activity, Letterman Army Med. Cent., Presidio of San Francisco, CA 94129, USA
SO: PLANT-AND-SOIL. 1982. vol. 66, no. 1, pp. 69-80
LA: English
ER: M (Marine)
AB: Element and extractant-specific desorption of Mn, Fe, Cu, and Zn from Spartina alterniflora detritus was observed. Desorption of a substantial fraction of the total detrital Mn, Fe, Cu and Zn occurred rapidly when the detritus was treated with 0.1 N HCl or 1 MgCl sub(2). This treatment removed precipitated/coprecipitated and adsorbed trace elements, respectively, suggesting that a large fraction of detritus-bound trace elements are in readily exchangeable, surface reaction sites. The carboxylic acid functional group cation exchange capacity of the detritus also suggests an important role of surface exchange reactions in the dynamics of trace elements during decomposition. The rate and magnitude of changes in the trace elements content of detritus has important implications for estuarine biogeochemical cycling of these elements including the potential for biological uptake of trace elements by detritus-consuming fauna.
AN: 0313233
248 of 369
TI: Marine Microcosms in Ecological Research.
AU: Pilson,-M.E.Q.; Nixon,-S.W.
AF: Grad. Sch. Oceanogr., Univ. Rhode Island, Kingston, RI 02881, USA
CO: Savannah River Ecology Laboratory Symposium, Augusta, Georgia (USA), 8-10 Nov 1978
SO: MICROCOSMS-IN-ECOLOGICAL-RESEARCH. Giesy,-J.P.,Jr.-ed. WASHINGTON,-D.C.-USA-TECHNICAL-INFORMATION-CENTER,-U.S.-DEPARTMENT-OF-ENERGY 1980. vol. 52 pp. 724-741
ST: DOE-SYMPOSIUM-SERIES. vol. 52
LA: English
ER: M (Marine)
AB: A major recent trend in marine research is the use of microcosms as living models of specific natural ecosystems or types of systems. Microcosms have always been used in research dealing with species succession, predator--prey interactions, etc., and much work has emphasized their use to explore the biogeochemical cycling of various materials, especially pollutants, and the effects of these materials on the biology and chemistry of marine ecosystems. This approach has generated interest in the problems involved with microcosm design and operation and the interpretation of complex multiparameter data sets obtained from supposedly replicate microcosms over long periods of time, Attempts have been made to design experimental systems in which light, flushing, surface-to-volume ratios, and turbulence are scaled appropriately and to evaluate the consequences, if any, of the exclusion of larger animals.
AN: 0266596
249 of 369
TI: Methane Flux in the Great Dismal Swamp.
AU: Harriss,-R.C.; Sebacher,-D.I.; Day,-F.P.,Jr.
AF: Mail Stop 270, NASA Langley Res. Cent., Hampton, VA 23665, USA
SO: NATURE. 1982. vol. 297, no. 5868, pp. 673-674
LA: English
ER: F (Freshwater)
AB: Methane is an important component of the biogeochemical cycle of carbon with potentially critical roles in both atmospheric chemical and radiation transfer processes. Limited evidence is available which suggests an increase in global tropospheric methane during the last decade. To understand and assess the possibility and implications of temporal variations in atmospheric methane requires improved quantitative knowledge of methane sources and sinks. The authors report methane flux measurements made over a 17-month period in the Great Dismal Swamp, Virginia. These flux measurements indicate that Great Dismal Swamp soils can act as both a source and sink for atmospheric methane. In a waterlogged condition, swamp soils are a net source of methane to the atmosphere with seasonal variations in emission rates from < 0.001 to 0.02 g CH sub(4) m super(-2) day super(-1). During drought conditions, swamp soils consume atmospheric methane at rates of < 0.001 to 0.005 g CH sub(4) m super(-2) day super(-1). While these results should not be extrapolated to all swamp soils, they illustrate the potential complexity of processes which regulate net flux of methane between wetland soils and the atmosphere.
AN: 0262008
250 of 369
TI: Effect of Different Nitrogen and Phosphate Sources on the Calcification in Gloeotaenium .
AU: Prasad,-P.V.D.; Chowdary,-Y.B.K.
AF: Dep. Bot., Banaras Hindu Univ., Varanasi-221005, Inida
SO: PHYKOS. 1981. vol. 20, no. 1&2, pp. 8-15
LA: English
ER: F (Freshwater)
AB: The effect of different nitrogen and phosphate sources on the calcification of G. loitlesbergarianum Hansgirg has been studied. Ammonia-nitrogen inhibited the calcification at very low concentrations (0.0006%) while nitrate-nitrogen and sulphate had no effect. This inhibitory effect of ammonia may be through the inhibition of photosynthesis. Both ortho and glycero phosphates inhibited the calcification even at 0.0001% concentration of the salt used, without affecting the alga.
AN: 0258924
251 of 369
TI: The Chemistry of Suspended Matter in Esthwaite Water, a Biologically Productive Lake With Seasonably Anoxic Hypolimnion.
AU: Sholkovitz,-E.R.; Copland,-D.
AF: Dep. Chem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA. 1982. vol. 46, no. 3, pp. 393-410
LA: English
ER: F (Freshwater)
AB: Ten vertical water column profiles were taken Apr. - Nov. 1979, in Esthwaite Water, a lake with high biological productivity and a seasonally anoxic hypolimnion. Measurements of the major-element particle composition (organic C, P, S, Si, Al, Ti, K, Mg, Ca, Fe, Mn, and Ba) and hydrochemical constituents (temp., pH, Do, total suspended load, dissolved Fe, Mn, P, and Ba) were carried out. These revealed new information on mechanisms and kinetics of biogeochemical cycles in lake. Pronouned seasonal cycles exist in which large excess concentrations (those unsupported by detrital components) of particulate organic C, Fe, Mn, P, S, Mg, K, Ba, and Ca are being generated and lost in situ in the water column (15 m). In the epilimnion these elements (excepting Fe and Mn) are incorporated into the organic components of growing phytoplankton during spring and summer. As the hypolimnion becomes anoxic, dissolved ferrous Fe is released from the sediments and large concentrations of excess particulate iron (III) oxides accumulate; these oxides act as adsorbing substrates for the above-mentioned elements. Adsorption equations are derived from the field data which relate the concentration of excess particulate Fe to those of POC, P, S, Ca, Mg, Ba, and K. At the last stages of anoxia (before the lake overturns) large populations of bacteria and the formation of iron sulfide particles control the concentrations of excess particulate C, S, P, Mg, K, and Ca.
AN: 0257396
252 of 369
TI: On the Mineralization of Organic Materials in the Coastal Marine Sediments.
AU: Yamada,-H.; Murakami,-A.; Kayama,-M.
AF: Nansei Regional Fisheries Research Lab., Ohno-cho, Hiroshima 739-04, Japan
SO: BULL.-JAP.-SOC.-SCI.-FISH. 1981. vol. 47, no. 2, pp. 171-177
LA: English
ER: M (Marine)
AB: The mineralization rate in the marine sediments was estimated in the coastal areas of Beppu Bay, Osaka Bay and Hiuchi Nada in the Seto Inland Sea by the kinetic approach method described by M.J. Harrison et al. The highest mineralization rate of sediments was measured on the surface in Hiuchi Nada, the second in Osaka Bay and the lowest in Beppu Bay. Vilable counts of heterotrophic bacteria on the surface of sediments of Osaka Bay and Hiuchi Nada were larger than those of Beppu Bay. Since the C/N ratio in Beppu Bay was larger than those in Hiuchi Nada and Osaka Bay, the activity of microorganisms was lower in Beppu Bay than that in the other two areas As the mineralization rate and the number of heterotrophs decrease significantly with the column depth of sediments, the surface of the important for the mineralization of organic materials. Comparing the mineralization rate on the surface of the sediments with that in the overlaying water, the percentage of the mineralization in the shallow waters like Osaka Bay was larger than that at the relatively deep waters of Beppu Bay.
AN: 0241655
253 of 369
TI: Environmental Quality Criteria: Some Considerations.
AU: Babich,-H.; Davis,-D.L.; Trauberman,-J.
AF: Environmental Law Inst., Washington, D.C., USA
SO: ENVIRON.-MANAGE. 1981. vol. 5, no. 3, pp. 191-205
LA: English
AB: The use of the term, ecological dosage 50% or EcD50, is recommended for the quantification of adverse effects of pollutants on microbe-mediated processes such as biogeochemical cycling, litter decomposition, and mineralization. This information was not considered in EPA's development of water quality criteria. Although few complete studies have been done in this field, a broad S-shaped curve can be plotted for respiration rate vs. concentration of pollutant. EcD50 values could be computed for individual pollutants, environments (such as a soil type), or processes. The advantages of EcD50 over LC50 are: (1) EcD50 from one ecosystem may be correlated with the same processes in a different ecosystem, and (2) a given EcD50 value reflects a group of mixed organisms and may be better applied to the total environment. The interactions between pollutant toxicity and abiotic factors justify setting different water quality standards for different regions. These physiochemical factors (such as pH, temperature, aeration state, and many others) affect a pollutant's chemical speciation form, mobility, and bioavailability. Cadmium and phenol are used as examples in the discussion of high risk environments, the partition between water column and sediments, and invisible injury to aquatic life.
AN: 0241499
254 of 369
TI: Biological Processes Affecting the Distribution of Pollutants in Marine Sediments. Part 1: Accumulation, Trophic Transfer, Biodegradation and Migration.
AU: Swartz,-R.C.; Lee,-H.,II
AF: U.S. EPA, Mar. Sci. Cent., OR 97365, USA
SO: CONTAMINANTS-AND-SEDIMENTS.-VOLUME-2:-ANALYSIS,-CHEMISTRY,-BIOLOGY. Baker,-R.A.-ed. ANN-ARBOR,-MI-USA-ANN-ARBOR-SCIENCE-PUBLISHERS-INC. 1980. vol. 2, pp. 533-553
LA: English
ER: M (Marine)
AB: The seabed is the ultimate sink for virtually every class of marine pollutant. Chlorinated hydrocarbons, petroleum hydrocarbons, metals and radionuclides are deposited in sediments and may persist there long after original sources of contamination are eliminated. This chapter deals with the biological processes that affect the biogeochemical cycling of contaminants in benthic ecosystems. Six processes were selected for discussion: bioaccumulation, trophic transfer, migration, biodegradation, biodeposition and bioturbation. The latter two are examined in the second part of the review (Chapter 29). For review purposes, uptake of pollutants via sediment ingestion is included in the section on bioaccumulation. With the exception of detrital food chains, the discussion of trophic transfer concerns the transport of pollutants from prey to predator. All spatial movements in which animals enter or leave areas of sediment contamination are included in the section on migrations. The discussion of biodegradation is restricted to the metabolism of pollutants by benthic animals.
AN: 0232232
255 of 369
TI: New Data on the Nature of Organic Matter in Oceanic Water and its Energy Resources.
OT: Novye Dannye o Prirode Organicheskogo Veshchestva Okeanskikh vod i Ego Ehnergeticheskie Resursy.
AU: Skopintsev,-B.A.
AF: Inst. Biol. Vnutr. Vod AN S.S.S.R., Borok, Yarosl. Obl., USSR
SO: OKEANOLOGIYA. 1981. vol. 21, no. 5, pp. 821-830
LA: Russian
ER: M (Marine)
AB: Conditions of humus formation in the ocean are described. New data on the nature of this organic substance are presented: predominance of the organic compounds of the aliphatic (acyclic) structure as compared with the predominance of the aromatic structure in terrestrial humus. For the first time the energy resources of the organic matter in oceanic waters are estimated and compared with similar resources of the terrestrial humus.
AN: 0231810
256 of 369
TI: Carbon and Nitrogen Fluxes During Decomposition of Spartina alterniflora in a Flow-Through Percolator.
AU: Marinucci,-A.C.
AF: Dept. Biochem. Microbiol., Cook Coll., New Jersey Agric. Exp. Stn., Rutgers State Univ. New Jersey, New Brunswick, NJ 08903, USA
SO: BIOL.-BULL.-MAR.-BIOL.-LAB.,-WOODS-HOLE. 1982. vol. 162, no. 1, pp. 53-69
LA: English
ER: B (Brackish)
AB: The carbon and nitrogen in S. alterniflora litter were monitored for 4 months during decomposition of 20 degree C in a flow-through percolator that simulates an aerobic, moist marsh. Both the evolution of CO sub(2) and the loss of carbon from the litter followed exponential decay kinetics (0.5% day super(-1) and 1.0% day super(-1)). At first both total organic carbon and total organic nitrogen were lost primarily in dissolved form at high rates, but this leaching ceased rapidly. The NH sub(4) added to the inflow was incorporated into the litter at about 0.25 mg N. g litter super(-1). day super(-1) initially, but the rate declined eventually to about 0.8 mg N.g litter super(-1). day super(-1) after 40 days. Nitrogen enrichment of the litter occurred in two phases with peaks on days 40 and 100. Nitrification started at day 30 and was the main consumer of NH sub(4). The final litter nitrogen concentration was 60% of the initial.
AN: 0228421
257 of 369
TI: Short-Term Starvation Effects on Nitrogen and Phosphorus Excretion by the Chaetognath Sagitta enflata .
AU: Szyper,-J.P.
AF: Oceanic Inst., Waimanalo, HI 96795, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1981. vol. 13, no. 6, pp. 691-700
LA: English
ER: M (Marine)
AB: Freshly captured Sagitta enflata exhibited specific excretion rates of ammonium and phosphate (expressed as percentage body content of N or P per hour) that were not significantly related to the size of individual animals. The degree of crowding in experimental vessels was positively correlated with specific excretion rates of ammonium. Excretion rates decreased sharply during the first several hours' incubation time, approaching the rates exhibited by animals starved overnight. Animals captured during the day in Kaneohe Bay, Hawaii, having no food items in their guts, had mean specific excretion rates ( plus or minus S.D.) of 0 multiplied by 81 plus or minus 0 multiplied by 51% body content of N h super(-1) for ammonium, and 1 multiplied by 29 plus or minus 1 multiplied by 24% body content of P h super(-1) for phosphate. Minimal estimates of natural excretion rates, made from the first hour of incubation in further experiments, were 1 multiplied by 19 plus or minus 0 multiplied by 47% h super(-1) for nitrogen and 3 multiplied by 8 plus or minus 3 multiplied by 95% h super(-1) for phosphorus. Sagitta is not a large contributor to nutrient regeneration in Kaneohe Bay.
AN: 0225005
258 of 369
TI: Distribution of Ionic Cu, Pb, Cd and Zn in the Adriatic Sea.
AU: Branica,-M.
AF: Cent. Mar. Res., Rudjer Boskovic Inst., Zagreb, Jugoslavia
CO: 4. Int. Symp. The Chemistry of the Mediterranean, Rovinj (Yugoslavia), 10 May 1976
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-SYMPOSIUM-THE-CHEMISTRY-OF-THE-MEDITERRANEAN. Commission-Int.-Pour-l'-Exploration-Sci.-de-la-Mer-Mediterrance,-Monaco 1978. vol. 14, no. 1-2 vol. 14, no. 1-2, pp. 151-155
ST: THALASSIA-JUGOSL. vol. 14, no. 1-2
LA: English
ER: M (Marine)
AB: The natural concentration of heavy metals in the marine environment is of great interest for prediction and estimation of pollution. The biogeochemical cycle of a particular pollutant strongly depends on the concentration, degree of actual physicochemical state and reaction pathways of this pollutant in a natural water system. Electrochemical methods, especially polarography and related techniques, have been developed and applied in the determination of trace metals in natural and polluted waters.
AN: 0215628
259 of 369
TI: An Annual Budget of Redox Active Materials in a Lake.
AU: Rich,-P.M.
CA: Connecticut Univ. Storrs (USA)
SO: STORRS,-CT-USA-CU 1980. 13 pp
LA: English
ER: F (Freshwater)
AB: The objectives of this project covered (1) the determination of gross and net flux of iron, nitrogen, and sulfur compounds (redox-active) between interstitial water of surface sediments and overlying lake water, through one annual cycle; (2) the determination of a synoptic material budget for the redox-active compounds in a small bog lake watershed; and (3) correlation of mineral activity in lake water and outflow stream with anaerobic benthic metabolism. It was noted that 50% more reducing power was generated as reduced alternate terminal electron acceptors in the lake (Durham Pond) as seen by reduction of oxygen to water; hence areal hypolimneti carbon dioxide increments better estimated total lake metabolism that areal hypolimnetic oxygen deficits. the watershed supplied more reducing power as dissolved organic matter than it supplied alternate electron acceptors on an annual basis. Finally, alternate electron acceptors were stored in oxidized from in surface sediments during ciruclation and high discharge periods, and used during both summer and winter stratification and low discharge. Hence, current input/output nutrient models accounted for a major biochemical energy transformation entraining redox-active elements and correlated within the lake ecosystem.
AN: 0211568
260 of 369
TI: Annual Oxygen Balance in the World Ocean.
AU: Ivanenkov,-V.N.
AF: Address not stated
SO: OCEANOL.-ACAD.-SCI.-USSR. 1980. vol. 20, no. 4, pp. 419-424
LA: English
ER: M (Marine)
AB: The annual oxygen balance in the World Ocean averages 212.10 super(9) metric tons/years, including: (a) supply: oxygen production through photosynthesis - 154 multiplied by 9 super(9) metric tons/year, oxygen supply to the ocean with rain and river waters - 3 multiplied by 10 super(9) metric tons/year and (b) expenditure: for biochemical oxygen consumption - 151 multiplied by 10 super(9) metric tons/year and for oxygen release from the ocean into the atmosphere - 61 multiplied by 10 super(9) metric tons/year. The resulting annual oxygen exchange between the ocean and the atmosphere (release into the atmosphere) is 6.5 multiplied by 10 super(9) metric tons/year which is similar to 4% of the annual oxygen production through photosynthesis. The annual oxygen balance is estimated for the Pacific, the Indian, the Atlantic and the Arctic oceans. It is equal to 170 multiplied by 10 super(9) metric tons/year in the Pacific, 97 multiplied by 10 super(9) t/year in the Indian Ocean, 87 multiplied by 10 super(9) metric tons/year in the Atlantic, and 4 multiplied by 10 super(9) metric tons/year in the Arctic Ocean. Oxygen exchange between the oceans is 24, 53, 59 and 80%, respectively, of the above-mentioned annual oxygen balance values in the oceans.
AN: 0182954
261 of 369
TI: Microbial Contribution to the Dynamics of Biological Elements in Marine Environments. April 5, 1980, Tokyo University at Yoyogi, Tokyo.
AU: Seki,-H.
AF: Address Not Stated
CO: Symposium - Microbial Contribution to the Dynamics of Biological Elements in Marine Environments, Tokyo (Japan), 5 Apr. 1980
SO: UMI-MER. 1980. vol. 18, no. 4, pp. 187-228
LA: Japanese
ER: M (Marine)
AB: Contributions cover: Carbon Cycle in the Ocean; Nitrogen Cycling with Special Reference to Ammonia Regeneration and Associated Food Chain; Autotrophic Processes with Special Reference to Microbial Activities; Heterotrophic Processes with Special Reference to Microbial Activities; and Mathematical Model on Dynamics of Biological Elements. A supplement deals with the carbon cycle of brain coral.
AN: 0162495
262 of 369
TI: Organic Matter in Bottom Sediments of the Pos'et Bay (Sea of Japan).
OT: Organicheskoe Veshchestvo v Donnykh Osadkakh Zaliva Pos'eta (Yaponskoe More)
AU: Andreeva,-N.M.; Agatova,-A.I.
AF: VNIRO, Moscow, USSR
SO: BIOL.-MORYA. 1981. no. 2, pp. 40-49
LA: Russian
ER: M (Marine)
AB: Investigations were carried out in biotopes of natural and artificially cultivated invertebrate populations (at depths of 2-45 m) in August 1977, July - August 1978 and May 1979. Wet samples of the upper 2 cm active layer of bottom sediments consisting of 2 layers differing in color and consistency were analyzed for the content of organic matter (OM), protein, carbohydrates, lipids, nucleic acids, chlorophyll a, b, c and carotenoids, for the protease and lipase activity and photosynthetic rate of phytobenthos. The total OM content in the upper active layer of bottom sediments was found to depend on the season and the metabolic activity of the mollusks in areas of their artificial cultivation. The OM content was lower in sands than in other sediment types. During the period of intensive photosynthesis the OM content in the sediments depended on the OM content in plankton. The qualitative composition of OM in the active layer underwent changes determined by the rate of enzymatic processes in the layer. these processes were more intensive in the upper than in the underlying layer and the upper layer can influence the qualitative composition of the underlying one.
AN: 0162378
263 of 369
TI: Seasonal Transformations and Movements of Iron in a Productive English Lake With Deep-Water Anoxia.
AU: Davison,-W.; Heaney,-S.I.; Talling,-J.F.; Rigg,-E.
AF: Freshwater Biol. Assoc., Ferry House, Ambleside, Cumbria, LA22 OLP, UK
SO: SCHWEIZ.-Z.-HYDROL.-REV.-SUISSE-HYDROL.-SWISS-J.-HYDROL. 1980. vol. 42, no. 2, pp. 196-224
LA: English
ER: F (Freshwater)
AB: The seasonal and depth distributions of the concentrations of total and soluble iron in a seasonally anoxic lake basin are described for two years. Transport of iron is related to hydrodynamics and fluxes of iron both within and to and from the lake are calculated. The results enabled the construction of a schematic model for iron movement; it is critically dependent upon the many rate processes involved.
AN: 0154718
264 of 369
TI: Trace Element Enrichments in Decomposing Litter of Spartina alterniflora .
AU: Breteler,-R.J.; Teal,-J.M.; Giblin,-A.E.; Valiela,-I.
AF: Battelle New England Mar. Res. Lab., 397 Washington Street, Duxbury, MA 02332, USA
SO: AQUAT.-BOT. 1981. vol. 11, no. 2, pp. 111-120
LA: English
ER: B (Brackish)
AB: Concentrations of mercury, copper, zinc, chromium, iron and manganese were measured in Spartina alterniflora Loisel. during different states of decomposition. Samples were collected from a salt marsh treated with a metal-containing sewage sludge and from a control marsh area. Overall, substantial increases were found in the concentrations of Hg, Cu, Fe, and Zn in all the Spartina litter samples collected. The trace-metal enrichment in the decaying Spartina grass was best explained by the adsorption of metal-enriched organic substances during tidal flooding of the marsh surface. No metal adsorption was observed from the sludge-treated marsh soil in spite of an elevation in several of the metals studied.
AN: 0144179
265 of 369
TI: Dissolved Chromium in the Northwest Atlantic Ocean.
AU: Campbell,-J.A.; Yeats,-P.A.
AF: Dept. Oceanogr., The University, Liverpool, L69 3BX, UK
SO: EARTH-PLANET.-SCI.-LETT. 1981. vol. 53, no. 3, pp. 427-433
LA: English
ER: M (Marine)
AB: Total dissolved chromium concentrations have been determined for four vertical profiles from Baffin Bay, the Labrador Sea and the northwest Atlantic Ocean. Chromium concentrations of 3.3 to 5.2nM are found. While the vertical distribution of chromium in the study area is largely controlled by advective processes, the profiles show a small depletion in surface water with increase to a more constant level at depth. Surface depletion and correlations between chromium and nutrients indicate biogeochemical cycling of chromium. At one station, close to the Gibbs fracture zone, a distinct chromium maximum is observed. This feature centred at 3200 m is deeper than the core of the ambient water mass which is advected westward from the Eastern Basin of the Atlantic Ocean through the Gibbs fracture zone.
AN: 0117016
266 of 369
TI: Cadmium, Zinc, Copper, and Barium in Foraminifera Tests.
AU: Boyle,-E.A.
AF: Dept. Earth Planet. Sci., Massachusetts Institute of Technology, Cambridge, MA 02139, USA
SO: EARTH-PLANET.-SCI.-LETT. 1981. vol. 53, no. 1, pp. 11-35
LA: English
AB: The concentrations of cadmium, zinc, copper and barium have been determined on 2-mg samples of single-species foraminifera populations, using North Atlantic core tops, and followed by a detailed downcore study for the last 30,000 years in South Atlantic core V22-174. Improved mechanical and ultrasonic reductive cleaning combined with a mild dissolution in distilled water under 1 atm. P sub(CO2) reduces contaminant levels another order of magnitude. The Cd and Zn concentrations (order 10 super(-8) mole Cd/mole Ca and 10 super(-5) mole Zn/mole Ca) of species with low surface area show an increase with decreasing isotopic temperatures. This increase is consistent with the increasing concentrations of these metals from low values in surface waters to higher values at depth. The variance of Cd and Zn over the last 30,000 years in the central South Atlantic is consistent with the probable variability of the dissolved trace elements at the calcification levels of the species analyzed. Cu and Ba are irreproducible and probably sensitive to residual contaminant phases. The trace element content of the tests differs from levels observed in a recent coprecipitation study. Foraminifera may be a significant vector in zinc cycling in the ocean.
AN: 0114674
267 of 369
TI: Differential Feeding and Fecal Pellet Composition of Salps and Pteropods, and the Possible Origin of the Deep-Water Flora and Olive-Green "Cells".
AU: Silver,-M.W.; Bruland,-K.W.
AF: Ctr. Coast. Mar. Stud., Univ. CA at Santa Cruz, Santa Cruz, CA 95064, USA
SO: MAR.-BIOL. 1981. vol. 62, no. 4, pp. 263-273
LA: English
ER: M (Marine)
AB: Salps (mainly Salpa fusiformis and, to a lesser extent, Pegea socia ) and a web-building pteropod (Corolla spectabilis ) were studied in epipelagic waters of central California Current. Fecal pellet analysis indicated that their diet differs significantly when they feed together, probably because of differences both in pore sizes of their nets and in feeding methods. Since fecal pellets transport most biogenic material to the deep sea, changes in herbivore species composition at a given geographic location can change the chemistry of materials entering deep water; at the study site, the more salps, the greater the calcite flux, and, the more pteropods, the greater the silica flux. In addition, fecal pellets of both salps and pteropods include partially digested residues of phytoplankton that appear as olive-green spheres, having an ultrastructure identical with that of the so-called olive-green "cells". Presumably, fecal pellets, after sinking into deep water, ultimately disintegrate, releasing both the viable phytoplankton and the olive-green spheres into aphotic waters. Thus the feces of epipelagic herbivores are likely sources of much of the flora of the deep ocean.
AN: 0114042
268 of 369
TI: Hydrochemical Basis of the Primary Production Process in the Coastal Waters of the Sea of Japan.
OT: Gidrokhimicheskie Osnovy Protsessa Pervichnogo Produtsirovaniya v Pribrezhnom Rajone Yaponskogo Morya
AU: Propp,-M.V.; Propp,-L.N.
AF: Inst. Biol. Morya DVNTs AN S.S.S.R., Vladivostok, USSR
SO: BIOL.-MORYA. 1981. no. 1, pp. 29-37
LA: Russian
ER: M (Marine)
AB: Complex seasonal observations of 19 hydrochemical and production parameters were made at the permanent station in the Vostok Bay of the Sea of Japan. This region is characterized by winter and summer - autumn outbreaks of phytoplankton development. The winter bloom is preceded by nitrate and ortho-phosphate accumulation in water and leads to their almost complete exhaustion. The summer bloom occurs after water temperature increase and acceleration of nitrogen (mainly in ammonia form) and phosphate regeneration at the bottom-water interface. The total nitrogen and phosphorus content, including organic forms, is found to vary approximately 3 times over the year, which points to the important role of the bottom regeneration of the nutrients. The higher productivity of the neritic marine as compared with pelagic ecosystem is believed to be due to accelerate cycles of nutrients.
AN: 0112662
269 of 369
TI: Chemical and Radiochemical Investigations of Surface and Deep Particles of the Indian Ocean.
AU: Krishnaswami,-S.; Sarin,-M.M.; Somayajulu,-B.L.K.
AF: Phys. Res. Lab., Ahmedabad 380009, India
SO: EARTH-PLANET.-SCI.-LETT. 1981. vol. 54, no. 1, pp. 81-96
LA: English
AB: The distribution of "ash" (the non-combustible fraction of marine suspended matter) and concentrations of particulate Al, Ca, Fe, Cr, Ni, Cu, Sr and super(234)Th in surface waters and of super(210)Pb, super(230)Th and super(234)Th in two vertical profiles (385-4400 m) of the Indian Ocean are reported. The ash concentrations in surface waters follow the primary productivity pattern, with higher abundances in samples south of 40 degree S and lower concentrations in the equatorial and subtropical regions. The high metal/Al ratio in surface particles most likely arises from their involvement in marine biogeochemical cycles. Particulate super(234)Th activity in surface waters parallels the ash abundance implying that its scavenging efficiency from surface waters depends on the particulate concentration. The particulate super(230)Th and super(210)Pb concentration profiles increase monotonously with depth. It is difficult to ascribe this increase to a process other than the in-situ vertical scavenging of super(230)Th and super(210)Pb from the water column by settling particles. The geographic distribution of particulate matter, composition and settling velocities in the Atlantic, Pacific and Indian Oceans are similar indicating that they are controlled by quite similar processes in the marine hydrosphere.
AN: 0112585
270 of 369
TI: Dissolved Cyclic Adenosine Monophosphate (cAMP) in the Sea and Uptake of cAMP by Marine Bacteria.
AU: Ammerman,-J.W.; Azam,-F.
AF: Univ. California, Inst. Mar. Resour., A-018, Scripps Inst. Oceanogr., San Diego, La Jolla, CA 92093, USA
SO: MAR.-ECOL.-PROG.-SER.. 1981. vol. 5, no. 1, pp. 85-89
LA: English
ER: M (Marine)
AB: Dissolved cyclic-3',5'-adenosine monophosphate (cAMP) was measured in coastal seawater. Concentrations of cAMP ranged from 1 to 35 x 10 super(-12) M being greatest in nearshore surface samples and from early evening through early morning. Dissolved cAMP was rapidly taken up intact by natural populations of marine bacteria, evidently via high affinity transport systems. Much higher concentrations were found in sediments. Presumed sources of dissolved cAMP are planktonic organisms (bacteria, algae, zooplankton, etc.). cAMP was also measurable in the plankton. Uptake of cAMP from seawater apparently increases the intracellular concentration of cAMP in marine bacteria and thus may play a role in their metabolic regulation.
AN: 0112296
271 of 369
TI: Inventory and origin of sterols in the marine atmosphere in the tropical north-eastern Atlantic.
OT: Inventaire et origine des sterols de l'atmosphere marine en Atlantique tropical nord-est.
AU: Tusseau,D.; Barbier,M.; Marty,J.C.; Saliot,A.-(Inst.-Chim.-Substances-Naturelles,-CNRS,-91190-Gif-sur-Yvette,-France)
SO: Oceanis-Doc.-Oceanogr., 1981 6(2), 167-179
LA: French
ER: M (Marine)
AB: This study was to discover whether the ocean is a source of organic matter, particularly sterols, for the atmosphere. Aerosols, surface microlayer and subsurface water samples have been collected in the tropical north-eastern Atlantic, during the MIDLANTE cruise of the Jean-Charcot-. The lipids have been extracted and the sterols analysed by liquid gas chromatography and mass spectrometry. For sea water and microlayer samples, dissolved and particulate sterols have been analysed separately. The data show that the marine atmosphere sterol content of this area is in the range 2.2-9.ng.mSUP--3, rough sea conditions leading to the highest concentration. The sterol compositions of atmosphere and particulate matter from sea water and the microlayer are very similar, characterized by a large predominance of cholesterol over other compounds, brassicasterol, -siterosterol, and 22-dehydrocholesterol. By comparing these results, it may be inferred that the sterols of the atmosphere are ejected from the ocean microlayer as particulates, at the first stage of the sterol cycle: ocean-atmosphere-continent. These observations emphasize the bio-ecological role of atmospheric sterols coming from the ocean.
AN: 0009180
272 of 369
TI: Data on the exchanges of particulate matter at the air-sea interface: geochemical implicatons.
OT: Donnees sur les echanges de matiere a l'etat particulaire a l'interface air-mer: implications geochimiques.
AU: Morelli,J.-(Minist.-Environ.-et-du-Cadre-de-Vie,-Mission-d'-Etudes-et-Recherche,-14,-Bd.-du-General-Leclerc,-92521-Neuilly-sur-Seine,-France)
SO: Oceanis-Doc.-Oceanogr., 1981 6(2), 109-151
LA: French
ER: M (Marine)
AB: This paper aims to distinguish the fundamental data on air-sea exchanges of particulate matter. It is based to a large extent on a bibliographic synthesis carried out as part of a doctorate thesis on the sea-salts atmospheric cycle, Morelli, 1977. After recalling the nature of the oceanic surface microlayer, attention is given to the oceanic bubbling phenomenon and the production of aerosols from bursting bubbles. Information is given on the composite character of particulate matter suspended in the marine atmosphere and originating not only from the ocean but also from the continental environment. This leads to an examination of the role of the ocean as a sink for this matter. Finally, the complex question of enrichments of marine aerosols components is approached and the geochemical implications are discussed from the point of view of the cyclic atmosphere supply of marine components to continents.
AN: 0009160
273 of 369
TI: Experimental study on metal fixation by a recent sedimentary organic matter of algal origin. 2. In vitro fixation of UO~SUP-2+~~SUB-2~, Cu~SUP-2+~, Ni~SUP-2+~, Zn~SUP-2+~, Pb~SUP-2+~, Co~SUP-2+~, Mn~SUP-2+~, and of VO~SUP--~~SUB-3~, MoO~SUP-2-~~SUB-4~ and GeO~SUP-2-~~SUB-2~.
OT: Etude experimentale de la fixation de metaux par un materiau sedimentaire actuel d'origine algaire _ II. Fixation 'in vitro' de UO~SUP-2+~~SUB-2~, Cu~SUP-2+~, Ni~SUP-2+~, Zn~SUP-2+~, Pb~SUP-2+~, Co~SUP-2+~, Mn~SUP-2+~, ainsi que de VO~SUB-3~~SUP--~, MoO~SUP-2-~~SUB-4~ et GeO~SUP-2-~~SUB-3~.
AU: Disnar,J-R.-(Bur.-Rech.-Geol.-Minieres,-Dep.-Mineral.,-Geochim.,-Analyses,-B.P.-6009-45060-Orleans-Cedex,-France)
SO: Geochim.-Cosmochim.-Acta, 1981 45(3), 363-379
LA: French
AB: The 'in vitro' metal fixation ability of a recent sedimentary organic matter of algal origin has been investigated with seven divalent cations (UOSUP-2+SUB-2, NiSUP-2+, MnSUP-2+, ZnSUP-2+, CoSUP-2+, PbSUP-2+, CuSUP-2+) and three anionic species (VOSUP--SUB-3, MoOSUP-2-SUB-4, GeOSUP-2-SUB-3). In the case of the cations, the great selectivity of the fixation, the independence of the amounts of metal fixed with regard to the cation exchange capacity of the organic matter and the existence of a 'pH effect', suggest the fixation mechanism to be a complexation chelation process. The similarities between the cation fixation capacity vs pH curves [in the 2 to (4-7) pH range] emphasize the existence of a common and determining step in the chelation mechanism for all the cationic species. This phenomenon is assessed to be an interaction between the cationic species and anionic carboxylate groupings. This first, non-selective, interaction is supposed to be followed by the formation of selective linkages between the metal and various organic functional groups.
AN: 1087920
274 of 369
TI: Experimental study in metal fixation by a recent sedimentary organic matter of algal origin. 1. Isolation, purification and characterization of the organic matter.
OT: Etude experimentale de la fixation de metaux par un materiau sedimentaire actuel d'origine algaire _ 1. Isolement, purification et caracterisation de la matiere organique.
AU: Disnar,J.-R.; Trichet,J.-(Bur.-Rech.-Geol.-Minieres,-Dep.-Mineral.,-Geochim.,-Analyses,-B.P.-6009-45060-Orleans-Cedex,-France)
SO: Geochim.-Cosmochim.-Acta, 1981 45(3), 353-362
LA: French
AB: In order to study the 'in vitro' fixation of metal ion species on algal and bacterial sedimentary organic matter, two algal mat samples have been studied. The main interest of this organic matter is its specific cyanobacterial origin. After isolation and purification, the organic matter was characterized by elemental and functional analysis, infrared spectroscopy, carbohydrates and amino-acid titration. These analyses indicate the richness of this type of organic matter in amino acids and carbohydrates, its poverty in aromatic structures, and to ascertain the types of bacteriological and chemical transformations undergone by the original biological compounds in the first steps of the diagenesis.
AN: 1087900
275 of 369
TI: Variations in the biological activity of the surface film in the course of the day.
OT: Variations de l'activite biologique du film superficiel au cours de la journee.
AU: Souza-Lima,Y.de; Daumas,R.-(Stn.-Mar.-d'-Endoume,-rue-de-la-Batterie-des-Lions,-13007-Marseille-Cedex,-France)
SO: Oceanis-Doc.-Oceanogr., 1981 6(2), 193-204
LA: French
ER: M (Marine)
AB: The presence of a great number of microorganisms at the surface film of sea water involves a great biological activity, either autotrophic or heterotrophic. Fluctuation in this biological activity during daytime is due mainly to special physical conditions such as solar radiation and the state of the sea. Measurements of the activity of the respiratory electron transport system (ETC), chlorophyll a concentrations and photosynthetic carbon fixation compared to biomass, suggest the migration of an important fraction of the biomass towards deeper layers, taking place mostly in the mid-afternoon, during summer.
AN: 0009200
276 of 369
TI: Excretion of dissolved organic phosphorus in tropical brackish waters.
AU: Lemasson,L.; Pages,J.-(Antenne-ORSTOM,-Station-INRA,-Avenue-de-Corzent,-74203-Thonon,-France)
SO: Estuar.-Coast.-Shelf-Sci., 1981 12(5), 511-523
LA: English
ER: B (Brackish)
AB: Dissolved organic phosphorus (DOP) release was measured on natural populations of a brackisk lagoon in the Ivory Coast (West Africa). DOP mean excretion is 8% of net phosphorus absorption, and represents 1.7% hSUP--1 of the biomass. Only 28% of biomass is involved in rapid uptake and excretion. Release of P is inversely proportional to the CSUB-p:NSUB-p ratio of the seston and the dissolved inorganic phosphorus concentration.
AN: 1087340
277 of 369
TI: Nutrient relationships in shallow water in an African lake, Lake Naivasha.
AU: Gaudet,J.J.; Muthuri,F.M.-(Univ.-Nairobi,-Dep.-Bot.,-PO-Box-30197,-Kenya)
SO: Oecologia, ISSN:-0029-8549 1981 49(1), 109-118
LA: English
ER: F (Freshwater)
AB: In the littoral zone of a shallow, tropical lake (Lake Naivasha, Kenya), average nutrient composition of emergent macrophytes along a permanent transect (0-2m depth) on a dry weight basis was: P 0.23%; N 0.96%; and S 0.11%. In the hydrosoil the average composition was much lower, sediments were: P 0.03%; N 0.24%; and S 0.05%. The water depth varied, with lake edge being exposed during the annual drawdown for a part of the year and subsequently being inundated. Water quality varied considerably during the year (temperature 19-28 C; pH 7.0-8.0; conductivity 282-975 ScmSUP--1). Of the three nutrients in the water of the littoral zone, N had the highest mean concentration (4.25 mg.lSUP--1) while P was intermediate (1.90) and sulphur had the least (0.99). The distribution of nutrients followed a decreasing gradient from shore to open water. High levels of nutrients were recorded in September following the inundation of drawdown soil and plant material. The large stock of nutrients generated in the littoral zone helps to replenish nutrients in the open lake where low concentrations are typical.
AN: 1010710
278 of 369
TI: Pathways of manganese in an open estuarine system.
AU: Sundby,B.; Silverberg,N.; Chesselet,R.-(Dep.-Oceanogr.,-Univ.-Quebec,-Rimouski,-Que.-G5L-3A1,-Canada)
SO: Geochim.-Cosmochim.-Acta, 1981 45(3), 293-307
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The distribution of Mn was examined in the bottom sediments and water column (suspended particulate matter) of the Laurentian Trough, Gulf of St. Lawrence. A characteristic profile of Mn with depth in the sediment consisted of a Mn-enriched surface oxidized zone, less than 20 mm thick, and a Mn-depleted subsurface reducing zone. A subsurface Mn maximum occurred within the oxidized zone. Below this maximum the concentration dropped sharply to nearly constant residual levels in the reducing zone. The accumulating estuarine sediments are deficient in Mn compared to the river input of suspended matter and are definitely not the ultimate sink for manganese. Manganese escapes from the sediment by diffusion and resuspension, forming Mn-enriched, fine-grained particles which are flushed out in the estuarine circulation, 5.0 x 10SUP-9 g/yr of Mn, or 50% more than the river input of dissolved Mn, are exported to the open ocean. In spite of the efficient mobilization and export of Mn, the quantity exported is a small fraction (0.2%) of the total flux to the deep-sea sediments. This is related to the low levels of particulate matter transported by the St. Lawrence River. The export phenomenon, however, is probably true of many coastal regions of muddy sediments and thus has interesting implications for the oceanic budget of Mn.
AN: 1083800
279 of 369
TI: Microbial control of organic carbon in marine sediments: coupled chemoautotrophy and heterotrophy.
AU: Kepkay,P.E.; Novitsky,J.A.-(Dep.-Oceanogr.,-Dalhousie-Univ.,-Halifax,-NS,-B3H-4J1,-Canada)
SO: Mar.-Biol., 1980 55(4), 261-266
LA: English
ER: M (Marine)
AB: The chemoautotrophic fixation of carbon dioxide is responsible for an appreciable component of the organic matter apparent as a carbon-rich peak at 40 cm sub-bottom in the marine muds of Halifax Harbour, Nova Scotia, Canada. Dissolved oxygen and sulfide profiles show that the 40 cm horizon represents a transitional environment from aerobic to underlying anaerobic conditions. A dissolved sulfate maximum and pH minimum at 40 cm indicate that sulfur-oxidizing chemoautotrophs are associated with the organic carbon production at this horizon. The stimulation of COSUB-2-fixation by thiosulfate and inhibition by anaerobic conditions, ammonia, nitrate and nitrite further support the contention that sulfur-oxidizers are primary producers at this horizon. Heterotrophic activity data show that both aerobic and anaerobic heterotrophs are active in the sediments. These data, in conjunction with the measurement of COSUB-2-fixation and the calculation of organic carbon accumulation over time, show that the peak of organic carbon observed is residual carbon that is not heterotrophically recycled to COSUB-2 at the 40 cm horizon.
AN: 1006400
280 of 369
TI: Studies on calcium, magnesium and sulphate in the Mandovi and Zuari River Systems (Goa).
AU: Sen-Gupta,R.; Naik,S.-(Natl.-Inst.-Oceanogr.,-Dona-Paula,-Goa-403-004,-India)
SO: Indian-J.-Mar.-Sci., 1981 10(1), 24-34
LA: English
ER: B (Brackish)
AB: Distribution of calcium, magnesium and sulphate have been examined in the tide-dominated Mandovi and Zuari river systems. Calcium and magnesium appears to take some part in the bio-geochemical cycles of the rivers and behave as semi-conservative parameters. Sulphate, however, behaves in a purely conservative manner and remains in a steady state in the rivers. A 'Simple mixture' relationship is applied to calculate the dilution and mixing processes in the rivers using calcium, magnesium and sulphate as indicators, it has been observed that the percentages of sea water in the estuarine region of Mandovi vary from 88-92 during premonsoon, 12-23 during monsoon and 78-79 during postmonsoon. Similar figures for Zuari are 94-99, 27-43 and 79-91 during the 3 seasons. The possibility of loss of calcium and magnesium due to precipitation as their insoluble phosphates in the upper reaches of the rivers is discussed.
AN: 1006350
281 of 369
TI: Denitrification and formation of extreme concentrations of nitrate and nitrite nitrogen in the Peruvian Upwelling Zone.
AU: Sapozhnikov,V.V.; Sviridova,I.V.-(Address-not-stated)
SO: Oceanol.-Acad.-Sci.-USSR, 1979 19(3), 273-275
LA: English
ER: M (Marine)
AB: Processes involving the transformation of nitrogen compounds under anaerobic conditions in a layer of sharp oxygen minimum (<0.1 ml OSUB-2/l) are examined in the Peruvian upwellng zone. It is shown that bacterial nitrate reduction or denitrification result in an accumulation of nitrites and in an associated reduction in the amount of nitrates. According to the denitrification equation, an increase in the ammonium nitrogen stocks (reserves) should take place, but this does not occur. It is assumed that ammonium N is accumulated by nitrobacteria during the reduction of nitrates. A new denitrification equation without ammonium N in the right-hand part is presented.
AN: 1061100
282 of 369
TI: Methane oxidation in Lake Tanganyika (East Africa).
AU: Rudd,J.W.M.-(Dep.-Fish.-Oceans-Freshwater-Inst.,-501-University-Crescent,-Winnipeg,-Manitoba-R3T-2N6,-Canada)
SO: Limnol.-Oceanogr., 1980 25(5), 958-963
LA: English
ER: F (Freshwater)
AB: Methane oxidation rates were measured at 5 stations on Lake Tanganyika. Oxidation occurred mainly within a narrow zone at the bondary of the seasonally mixed layer and the permanently anoxic monimolimnion. Whole lake methane oxidation rates were estimated to have varied seasonally from 3.8 to 5.8 mmol CHSUB-4.mSUP-2.dSUP--1. The annual rate was tentatively estimated to be about 3.1 mmol CHSUB-4.mSUP--2.yrSUP--1, equivalent to at least 10% of annual primary productivity. Certain differences and similarities of methane cycling in Lakes Tanganyika and Kivu are compared to those in lakes of other types.
AN: 1057600
283 of 369
TI: Variations of stable hydrogen isotopes in plankton from a freshwater lake.
AU: Stiller,M.; Nissenbaum,A.-(Isot.-Dep.,-Weizmann-Inst.-Sci.,-Rehovot,-Israel)
SO: Geochim.-Cosmochim.-Acta, 1980 44(8), 1099-1101
LA: English
ER: F (Freshwater)
AB: The isotopic composition of the organically bonded hydrogen in microplankton and zooplankton samples collected monthly from Lake Kinneret during 1972 and 1973 ranges between -90 and -130o/oo. The temporal variations which have been observed in the deuterium content of the plankton samples, seem to be controlled by metabolic processes and not by variations in the temperature and in the deuterium content of the lake water. The organic material of the zooplankton is consistently enriched in deuterium, by about 20o/oo as copared to that of the phytoplankton.
AN: 1056790
284 of 369
TI: Polychlorinated biphenyls in sediments of the tidal Hudson River, New York.
AU: Bopp,R.F.; Simpson,H.J.; Olsen,C.R.; Kostyk,N.-(Lamont-Doherty-Geol.-Obs.,-Columbia-Univ.,-Palisades,-NY-10964,-USA)
SO: Environ.-Sci.-Technol., 1981 15(2), 210-216
LA: English
ER: B (Brackish); F (Freshwater)
AB: As the result of discharges of PBCs from two manufacturing facilities on the upper Hudson River between ca 1950 and 1976, recent sediments of the tidal Hudson have been contaminated to an average level of 10 ppm. This is 1-2 orders of magnitude higher than levels in a number of other large rivers and estuaries that have been studied. The degree of contamination decreases regularly with distance downstream from the source. Downstream changes in PCB composition along the axis of the Hudson can be understood qualitatively in terms of suspended matter-water partitioning of PCB components. The presence of SUP-137Cs in the sediments can be used as an independent indication of sediment deposition since the era of atmospheric testing of nuclear weapons. SUP-137Cs and PCB depth profiles in cores are used to determine a first-order PCB budget for sediments of the tidal Hudson and to indicate regional levels of PCB contamination prior to the large point-source discharges to the upper Hudson.
AN: 1050650
285 of 369
TI: Formation of C~SUB-4~-C~SUB-7~ hydrocarbons from bacterial degradation of naturally occurring terpenoids.
AU: Hunt,J.M.; Miller,R.J.; Whelan,J.K.-(Woods-Hole-Oceanogr.-Inst.,-Woods-Hole,-MA-02543,-USA)
SO: Nature, 1980 288(5791), 577-578
LA: English
ER: M (Marine)
AB: The authors found many light hydrocarbons, both alkanes and alkenes, in trace amounts (ng compound per g sediment) in recent marine sediments. These hydrocarbons are believed to originate from both biological and low-temperature reactions in the sediments. Understanding their mechanism of formation may allow use of these compounds to decipher the past biological and thermal history of the sediments. To investigate biological origins the authors cultivated mixed populations of bacteria on natural terpenoids and found, as degradation products, both alkanes and alkenes in the CSUB-1-CSUB-7 range; this is the first report of CSUB-4-CSUB-7 hydrocarbons being formed from microbial activities. Aerobic followed by anaerobic degradation yielded mainly small amounts of straight-chain alkenes. No such products resulted from blanks or controls. The results are consistent with products observed in natural environments.
AN: 1039240
286 of 369
TI: Transportation and enrichment of chlorinated phenolic compounds in different aquatic food chains.
AU: Paasivirta,J.; Sarkka,J.; Leskijarvi,T.; Roos,A.-(Dep.-Chem.,-Univ.-Jyvaskyla,-Kyllikinkatu-1-3,-40100-Jyvaskyla-10,-Finland)
SO: Chemosphere, 1980 9(7-8), 441-456
LA: English
ER: F (Freshwater)
AB: Food chain and sediment samples of 3 lake areas in Middle Finland were analyzed for their chlorophenol contamination using 12 model compounds which are main residues of chlorobleaching and wood preservation. Six of these compounds were commonly found. Statistical treatment of the analysis results indicate that tetrachloroguaiacol is the most potent biocide of the compounds studied.
AN: 1045470
287 of 369
TI: Phosphorus and nitrogen in the Mediterranean Sea, budgets and potential fertility. /
OT: Le phosphore et l'azote en mer Mediterranee, bilans et fertilite potentielle.
AU: Bethoux,J.P.-(Lab.-Phys.-Chim.-Mar.,-Univ.-Paris-6,-ERA-CNRS,-Stn.-Mar.-BP8,-06230-Villefranche-sur-mer,-France)
SO: Mar.-Chem., 1981 10(2), 141-158
LA: French
ER: M (Marine)
AB: Owing to the P concentrations in the deep waters and the terrestrial discharges, the balance of this element requires low concentrations in the surface layers (<0.1 g P/l) which appear to be in agreement with the measured phosphate concentrations in the Strait of Gibraltar and in the Strait of Sicily. The P cycle in the Mediterranean Sea is characterised by the transfer of the terrestrial and Atlantic influxes from the surface layer to the intermediate and deep layers. The geographic distribution of the terrestrial discharges is highly asymmetric, and the vertical movements of the water masses in certain regions induce an important hydrologic recycling of P. The potential fertility is estimated from the local surface P flows and from the hydrologic recycling. Its values range, in the Western basin, between 9 and 86 g C/m/y in the Southern and Northern parts of this basin, respectively. In addition to biological reasons, the N budget in the Mediterranean Sea should be comparable to that of P because the geographical variations of the nitrate concentrations in the deep waters and the distribution of terrestrial discharges are similar to those of P. However, the relatively low values of terrestrial discharges of N proposed by UNEP do not allow a balance of this nutrient unless a high concentration in the Atlantic surface waters is introduced.
AN: 1049550
288 of 369
TI: Physico-chemical processes of silicates in the estuarial region. 4. An analysis of the mechanism of removal of reactive silicate in the estuarial region.
AU: Li,F.-(Dep.-Oceanogr.,-Xiamen-Univ.,-China)
SO: Acta-Oceanol.-Sin., 1980 2(1), 43-56
LA: Chinese
ER: B (Brackish)
AB: The controversy among recent investigators on the problem whether there is any extent of inorganic removal of reactive silicate in the estuarial regions is reviewed and discussed on appropriate theoretical, experimental, and in situ observational bases. A mathematical model based on mixing ratios of different water sources has been proposed, and theoretical equations for reactive silicate vs chlorosity relations for various cases have been derived, assuming reactive silicate to be a conservative constituent. The extent of silicate removal may then be estimated. Arguments have been admitted about the inference drawn by Wollast and De Broeu, and also by Fanning and Pilson, that the silicate removal is mostly biological. It is suspected whether the results of the laboratory experiments by the above authors can ever rule out the possibility of significant inorganic removal. As in parts II and III of this series of papers, the simulation experiments showing the occurrence of chemical adsorption of soluble silicate on colloidal Fe(OH)SUB-3 and Al(OH)SUB-3 precipitates, and the analytical data of the suspended matter in the estuarial waters showing the stoichiometric ratios between the 'authigenic' Si, Fe and Al contents and the smaller amount of organic Si than that of 'authigenic' inorganic Si in the suspended matter, have given good evidence for the occurrence of inorganic removal of reactive silicate and also the possibility of transforming into certain kinds of more stable silicate compounds of Al and or Fe after removal.
AN: 1004790
289 of 369
TI: Methylmercury production in the marine water column.
AU: Topping,G.; Davies,I.M.-(Dep.-Agric.-Fish.-Scotland,-Mar.-Lab.,-Victoria-Rd.,-Aberdeen-AB9-8DB,-UK)
SO: Nature, 1981 290(5803), 243-244
LA: English
AB: Although the biosynthesis of methylmercury in sediments is well established, this is not necessarily the exclusive natural source of methylmercury entering the marine food chain, particularly commercial fish and shellfish species for human consumption. An examination of mercury levels in freshwater fish, collected from a lake with a history of industrial mercury contamination, suggested that levels in fish are controlled in part by mercury in suspension and it followed that methylation should occur in the water column. Although methylmercury is present in seawater in coastal areas receiving discharges of waste containing either inorganic mercury or methylmercury there is no evidence that methylmercury is actually formed in the water column. The authors present data which demonstrate that inorganic mercury can be methylated in the water column and compare this production with that known to occur in marine sediments.
AN: 1055330
290 of 369
TI: Inorganic lead complexation in natural seawater determined by UV spectroscopy.
AU: Byrne,R.H.-(Dep.-Mar.-Sci.,-Univ.-South-Florida,-St-Petersburg,-FL-33701,-USA)
SO: Nature, 1981 290(5806), 487-489
LA: English
ER: M (Marine)
AB: Recent effort to construct trace metal complexation models in natural media is a mark of the importance of chemical form in the biogeochemical behaviour of trace metals. Unfortunately such chemical modelling is difficult in many ways. Chemical speciation models of trace metals in complex natural media such as seawater are usually constructed using stability constants determined in simple media. The authors describe an alternative procedure which can reduce the errors inherent in this approach. Using UV spectroscopy, lead speciation in seawater is examined. The method is a means of describing metal speciation in seawater quantitatively using stability constants determined exclusively in seawater. Preliminary experiments indicate that the same approach can be used for other metals including copper.
AN: 1055320
291 of 369
TI: Arsenic cycling in marine systems.
AU: Sanders,J.G.-(Woods-Hole-Oceanogr.-Inst.,-Woods-Hole,-MA-02543,-USA)
SO: Mar.-Environ.-Res., 1980 3(4), 257-266
LA: English
ER: M (Marine)
AB: The arsenic cycle in productive, near-shore marine systems is complex, involving both geochemical inputs and outflows and biological mediation. The major input to the Georgia Bight is intrusion of subsurface Gulf Stream water; in other marine systems, river run-off and atmospheric deposition may provide a large percentage of the arsenic input. Indiscriminate biological uptake is responsible for changes in arsenic speciation, involving approximately 20% of the dissolved arsenate pool and resulting in measurable concentrations of reduced and methylated arsenic species. The overall cycle is similar to the phosphate cycle; however, regeneration time for arsenic is much slower.
AN: 0009740
292 of 369
TI: Pathways and mechanisms for removal of dissolved organic carbon from leaf leachate in streams.
AU: Dahm,C.N.-(Dep.-Fish.-Wildl.,-Oregon-State-Univ.,-Corvallis,-OR-97331,-USA)
SO: Can.-J.-Fish.-Aquat.-Sci., 1981 38(1), 68-76
NT: Incl. bibliogr.: 51 ref.
LA: English
ER: F (Freshwater)
AB: Removal of dissolved organic carbon (DOC) from water resulting from adsorption and microbial uptake was examined to determine the importance of biotic and abiotic pathways. Physical-chemical adsorption to components of the stream sediment or water and biotic assimilation associated with the microbial population was determined in recirculating chambers utilizing leachate from alder (Alnus rubra-). Adsorptive mechanisms were further separated into interactions involving (1) specific clay minerals, (2) amorphous solid phases of hydrous aluminum and iron oxides; and (3) fine particulate organic matter. Physical-chemical adsorptive mechanisms for alder leachate removal exhibited rapid kinetic equilibration between the DOC and solid phases, but only a specific fraction of the DOC, likely containing certain chemical functional groups, was adsorbed. The amorphous aluminum and iron oxides possessed a much higher potential capacity than the clay minerals or fine particulate organics for DOC adsorption,. Microbial uptake of DOC from the alder leachate was kinetically slower than adsorptive uptake. However, microbial activity was overall much more effective in the removal and degradation of the total DOC pool leached from alder leaves. Over a 48-h period, 97% of added U1SUP-4C labeled leachate was removed from solution by adsorption (ca. 20%) and microbial utilization (ca. 77%). The rate of microbial uptake was 45 g C/g sediment C/h or 14 mg C/mSUP-2/h.
AN: 1000090
293 of 369
TI: Adenosine triphosphate and adenylate energy charge in marine sediments.
AU: Christensen,J.P.; Devol,A.H.-(Univ.-Washington,-Coll.-Fish.,-WH-10,-Seattle,-WA-98195,-USA)
SO: Mar.-Biol., ISSN:-0025-3162. 1980 56(3), 175-182
LA: English
ER: M (Marine)
AB: The determination of adenosine triphoshate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) concentrations in sediments from both Puget Sound and the Washington State continental shelf (USA) has been investigated. Major losses during the extracton procedure included sediment sorption, coprecipitation, and unreactivity of the soluble adenylates presumably through irreversible binding to solubilized sediment organics. Addition of phosphoric acid and the non-ionic detergent Triton X-100 to cold sulfuric acid significantly increased the extraction efficiency and sensitivity over that of sulfuric acid alone, although both methods yielded similar results when corrected for losses. Vertical profiles of ATP, total adenylates (ASUB-T), and adenylate energy charge (EC) in sediments from both areas are presented. Profiles of ASUB-T are similar in both areas, but EC values in the shelf sediments are significantly lower, which suggests a depressed physiological condition in the shelf population relative to that in Puget Sound.
AN: 1005280
294 of 369
TI: Concentration and microbiological utilization of small organic molecules in the Scheldt estuary, the Belgian coastal zone of the North Sea and the English Channel.
AU: Billen,G.; Joiris,C.; Wijnant,J.; Gillain,G.-(Lab.-Oceanogr.,-Univ.-Bruxelles,-Brussels,-Belgium)
SO: Estuar.-Coast.-Mar.-Sci., 1980 11(3), 279-294
LA: English
ER: M (Marine); B (Brackish)
AB: Concentrations and utilization rates of alanine, aspartate, lysine, glucose, glycollic, acetic and lactic acids have been determined on 6 occasions at least, during a full seasonal cycle in the water column of 3 stations (Scheldt estuary, coastal North Sea and English Channel) with greatly differing biological characteristics. No significant differences in substrate concentration could be detected between the 3 stations, although the rate of utilization of all substrates differed greatly, decreasing in the order estuarine > coastal > open sea environment. This apparent paradox is explained by aid of a simple model showing that the steady state concentration of a particular substrate is independent of its rate of production (and thus of consumption) and depends only on purely physiological characteristics of the bacteria. Using published data for the pertinent physiological parameters of marine bacteria, the model accounts for at least the order of magnitude of substrate concentrations observed, and the absence of important seasonal variations.
AN: 1038060
295 of 369
TI: Phosphate uptake by phytoplankton in the central North Pacific Ocean.
AU: Perry,M.J.; Eppley,R.W.-(Oceanogr.-Dep.,-Washington-Univ.,-Seattle,-WA-98195,-USA)
SO: Deep-Sea-Res., 1981 28(1A), 39-49
LA: English
ER: M (Marine)
AB: The central North Pacific Ocean (CNP) is an oligotrophic environment characterized by low concentrations of plankton biomass and of dissolved nitrogen and phosphorus compounds. The dynamics of phosphorus utilization was examined to test the hypothesis that phosphorus controlled phytoplankton growth rates. Rates of phosphate uptake were measured in natural assemblages using SUP-33P-phosphorus and were compared with rates of SUP-15N-nitrogen and SUP-14C-carbon assimilation. Phosphate uptake was linear over 24 h. Turnover times for phosphate averaged 28 d in Feb, 19 d in June, and 31 d in Dec. Zooplankton regeneration accounted for 55 to 183% of the daily phytoplankton phosphate requirement. Growth rates of phytoplankton in the mixed layer, calculated from SUP-33P-phosphorus uptake, were 9% of the maximum rate at ambient central North Pacific temperatures and averaged 0.14 doublings/d. Assimilation ratios of C, N, and P suggested nitrogen-limited, rather than phosphorus-limited, growth. Physiological adaptions, such as low KSUB-m for phosphate uptake, light-independence of uptake, and derepressible alkaline phosphatase, may prevent the onset of phosphorus stress.
AN: 1004610
296 of 369
TI: The mean residence time of plankton-derived carbon in a Long Island Sound sediment core: a correction.
AU: Turekian,K.K.; Benoit,G.J.; Benninger,L.K.-(Dep.-Geol.-Geophys.,-Yale-Univ.,-New-Haven,-CT-06520,-USA)
SO: Estuar.-Coast.-Mar.-Sci., 1980 11(5), 583
LA: English
ER: M (Marine)
AB: An error is reported and corrected with reference to a recent paper by the authors (Estuarine and Coastal Mar. Sci. 10, p. 178 (1979)). The value of 28 days for the mean residence time relative to metabolic regeneration of plankton-derived carbon in the top 5 cm of a Long Island Sound sediment core is now corrected to 2.2 years, and a revised equation is given.
AN: 1047700
297 of 369
TI: Removal of 'soluble' iron in the Potomac River Estuary: a reply.
AU: Eaton,A.-(J.M.-Montgomery,-Inc.-555-E.-Walnut-St.,-Pasadena,-CA-91101,-USA)
SO: Estuar.-Coast.-Mar.-Sci., 1980 11(5), 589-591
LA: English
ER: M (Marine); B (Brackish)
AB: Sholkovitz (1980) states that the observations of Eaton (1979) on freshwater removal of soluble Fe in the Potomac River actually represent cation coagulation at very low salinities. It is shown here that the salinity does not change over the region of Fe removal and thus the original hypotheses of Eaton (1979) are a better explanation in this case.
AN: 1038020
298 of 369
TI: Removal of 'soluble' iron in the Potomac River Estuary: comments.
AU: Sholkovitz,E.R.-(Univ.-Edinburgh,-Grant-Inst.-Geology,-West-Mains-Rd.,-Edinburgh-EH9-3JW,-UK)
SO: Estuar.-Coast.-Mar.-Sci., 1980 11(5), 585-587
LA: English
ER: M (Marine); B (Brackish)
AB: Eaton (1979) states that the removal of soluble Fe in the Potomac River estuary does not result from the coagulation of Fe-colloids by seawater cations but rather by the destabilizing action of 'bacterial polymers'. The data of Eaton are used to demonstrate that the removal mechanism is cation coagulation, the same process as observed in other estuaries.
AN: 1038010
299 of 369
TI: Annual oxygen balance in the World Ocean.
OT: Godovoj balans kisloroda v Mirovom okeane.
AU: Ivanenkov,V.N.-(Inst.-Okeanol.-AN-SSSR.,-Moscow,-USSR)
SO: Okeanologiya, ISSN-0030-1574 1980 (no. 4), 637-644
NT: Incl. bibliogr.: 39 ref.
LA: Russian
ER: M (Marine)
AB: The annual oxygen balance in the World Ocean averages 212.10SUP-9t/year made up of (a) supply: 154.10SUP-9t/year produced through photosynthesis, 55.10SUP-9t/year absorbed from the atmosphere, 3.10SUP-9t/year arriving with rain and river water and (b) expenditure: 151.10SUP-9t/year for biochemical oxygen consumption and 61.10SUP-9t/year for release to the atmosphere. These oxygen balance components have a 10-15% error. The resultant of the annual ocean-atmosphere oxygen exchange (release to the atmosphere) amounts to 6.510SUP-9t/year which is ca. 4% of the annual oxygen production through photosynthesis. The annual oxygen balance is 170.10SUP-9t/year for the Atlantic and 4.10SUP-9t/year in the Arctic Ocean, the oxygen exchange between the oceans (which is not taken into account in estimating the annual oxygen balance in the World Ocean) being 24, 53, 59 and 80% respectively of the above annual oxygen balance values in the oceans.
AN: 1000940
300 of 369
TI: Biogeochemical investigations of some continental water systems in Yugoslavia by instrumental activation analysis.
AU: Draskovic,R.J.; Draskovic,R.S.-(Boris-Kidric-Inst.-Nucl.-Sci.,-Vinca,-Lab.-Radioisotopes,-Beograd,-POB-522,-Yugoslavia)
SO: J.-Radioanal.-Chem., 1980 58(1-2), 275-280
LA: English
ER: F (Freshwater)
AB: The theoretical approaches to the biogeochemical examination of continental water systems in Yugoslavia are discussed. These water systems have been characterized by the parameters (partial and integral contents of elements CSUB-X) of the components of these systems, vir. living and non-living matter (non-living matter: materials dissolved in water CSUB-W, suspended and bed materials CSUB-sm and CSUB-bm, soil in the rivers basin CSUB-s; living matter CSUB-vivo; plankton CSUB-p, alga CSUB-al, benthos CSUB-b, shells and crustacea CSUB-sc, fish CSUB-f). The values of the integral contents of Cr, Sb, Sc, Fe, Co, La and Na in the components of the rivers Danube, Sava, V. Morava, Tisa and Karas are presented and discussed.
AN: 1025860
301 of 369
TI: The behavior of ~SUP-14~C and ~SUP-13~C in estuarine water: effects of in situ CO~SUB-2~ production and atmospheric exchange. /[Proceedings of:- 10. International Radiocarbon Conference; Heidelberg (GFR); 19 Aug 1979].
AU: Spiker,E.C.-(US-Geol.-Surv.,-Reston,-VA-22092,-USA)
CO: /[Proceedings of:- 10. International Radiocarbon Conference Heidelberg (GFR) 19 Aug 1979].
SO: Radiocarbon, 1980 22(3), 647-654
LA: English
ER: B (Brackish)
AB: The effects of nonconservative sources (inputs) and sinks (outputs) of carbon are indicated by the behavior of SUP-14C and SUP-13C of the total dissolved inorganic carbon (|COSUB-2) in San Francisco Bay and Chesapeake Bay. Isotopic distributions and model calculations indicate that in North San Francisco Bay the net COSUB-2 flux to the atmosphere and carbon utilization in the water column are balanced by benthic production. Municipal waste appears to be a dominant source in South San Francisco Bay. In Chesapeake Bay, atmospheric exchange has increased the SUP-14C and SUP-13C in the surface water. Decomposition of organic matter in the water column is indicated to be the dominant source of excess |COSUB-2 in the deep water.
AN: 1024510
302 of 369
TI: Biogeochemical cycling in an organic rich coastal marine basin. II. Nutrient sediment-water exchange processes.
AU: Val-Klump,J.; Martens,C.S.-(Cent.-Great-Lakes-Stud.,-Univ.-Wisconsin-Milwaukee,-Milwaukee,-WI-53201,-USA)
SO: Geochim.-Cosmochim.-Acta, 1981 45(1), 101-121
LA: English
ER: M (Marine)
AB: The release of remineralized N and P from the organic-rich anoxic sediments of Cape Lookout Bight is controlled by processes occurring within the sediment column and at the sediment-water interface. The relatively rapid rates of temperature dependent microbial degradation of organic matter support seasonally varying nutrient fluxes ranging from 20 to 1200 mol/mSUP-2/h for dissolved ammonium and from -20 to 120 mol/mSUP-2/h for total dissolved phosphate (measured in situ over the period Oct, 1976 to Oct 1978). Gradients for ammonium and phosphate ranged from 0.33 to 1.10 and from 0 to 0.29 mol/cmSUB-pwSUP-3/cmSUB-s, respectively. These high summertime fluxes appear to result from increased sediment-water transport associated with bubble tubes created and maintained by low-tide methane gas bubble ebullition. When these tubes are present, apparent bulk sediment diffusivities calculated from concurrent studies of methane and radon-222 sediment-water exchange are 1.0-3.1 times greater than molecular diffusivities. Nutrient fluxes calculated via Fick's first law indicate that removal by aerobic adsorption and/or biological uptake at the sediment-water interface plays an important role in controlling nutrient exchange in these sediments.
AN: 1038200
303 of 369
TI: A hydrogeochemical survey of the chalk groundwater of the Banstead area, Surrey, with particular reference to nitrate.
AU: Young,G.P.; Morgan-Jones,M.-(Resour.-Div.,-Water-Res.-Cent.)
SO: J.-Inst.-Water-Eng.-Sci., 1980 34(3), 213-236
LA: English
ER: F (Freshwater)
AB: Concentrations of nitrate close to, or exceeding WHO's recommended European standard (11.3 mg N/L) have been measured in groundwater from a number of chalk sources in the UK in the last decade. A research programme was initiated in 1974 by the Water Research Centre with the objectives of (1) determining the extent of nitrate pollution in main UK aquifers; and (2) identifying and, if possible, quantifying the factors responsible for the accumulation, convection, and dispersion of nitrate within the aquifers. This paper records investigtions west of Central London in the Sutton District Water Co. supply catchment. The groundwater was shown to be of typical CaHCOSUB-3 type. A seasonal variation in the concentrations of certain solutes indicates that a proportion of the recharge moves rapidly from the surface to the water table. With the exception of Pb trace metals showed no significant variations. Evidence suggests nitrate rich groundwater is generally restricted to the upper layers of the water table. Two possible sources of nitrate were identified as mineralization of soil organic material arising from urbanization of the northern part of the area and the increase in arable farming, with more extensive use of fertilizers after World War 2.
AN: 1013520
304 of 369
TI: Biogeochemical processes affecting metal concentrations in lake sediments (IJsselmeer, The Netherlands).
AU: Salomons,W.; Mook,W.G.-(Delft-Hydraulics-Lab.,-Haven-Branch,-Oosterweg-92,-9751-PK-Haren,-Gr.,-Netherlands)
SO: Sci.-Total-Environ., 1980 16(3), 217-229
LA: English
ER: F (Freshwater)
AB: The IJsselmeer originated in 1932 when a former coastal lagoon was shut off from the North Sea. Its main source of water and sediments is from the highly polluted river Rhine. The lake acts as a sink not only for particulate trace metals, but also for the dissolved metals; especially dissolved zinc, chromium and cadmium are held back in the lake. For these metals field and laboratory experiments revealed a correlation between pH and element concentrations where adsorption strongly depends on the pH within the range 7-9 observed in the IJsselmeer. Algae account for about 4-14% of the removal cadmium, chromium, zinc and copper. In the mouthing area of the river IJssel, metal concentrations in the sediments are determined by physical (mixing of lake and river sediments) and by chemical processes (adsorption). Mixing of the sediments has been quantitatively studied with the aid of natural stable isotope tracers. Between 1932 and 1974 trace metal concentrations in the sediments show increases between 25% (chromium) and 600% (cadmium). Organic matter concentrations increased by 140%, calcium carbonate by300% and phosphorus by 600%.
AN: 1012530
305 of 369
TI: Marsh plants as vectors in trace metal transport in Oregon tidal marshes.
AU: Gallagher,J.L.; Kibby,H.V.-(Coll.-Mar.-Stud.,-Univ.-Delaware,-Lewes,-DE-19958,-USA)
SO: Am.-J.-Bot., 1980 67(7), 1069-1074
LA: English
ER: B (Brackish)
AB: The role of Pacific coast marsh plants as vectors in the flux of trace metals was studied in natural and perturbated situations. The flux of Cr, Cu, Fe, Mg, Sr, and Zn were studied in natural stands of Carex lyngbyei, Distichlis spicata, Potentilla pacifica-, and Salicornia virginica-. Seasonal fluxes of trace metals into the shoots of the living plants were measured as was their transfer to the dead plant community through mortality. Disappearance from the latter community (through fragmentation, leaching and excretion) was calculated. Seasonal data were summed to produce annual input-output budgets. The flux varied from 3 mg/mSUP-2 for Cr in a stand of Potentilla pacifica- to 15000 mg/mSUP-2 for Fe in Carex lyngbyei-). The uptake of trace metals from contaminated dredged material was compared with that from natural soils using modified buckets placed in the marsh. Four plants (C. lyngbyei, D. spicata, Deschampsia cespitosa-, and S. virginica-) were tested for Cd, Cr, Cu, Pb and Zn. Copper was the only metal accumulated from contaminated soils in the situations tested.
AN: 1008250
306 of 369
TI: Relationships between microbial distributions and the anaerobic decomposition of organic matter in surface sediments of Long Island Sound, USA.
AU: Aller,R.C.; Yingst,J.Y.-(Dep.-Geophys.-Sci.,-Univ.-Chicago,-5734-South-Ellis-Ave.,-Il-60367,-USA)
SO: Mar.-Biol., 1980 56(1), 29-42
LA: English
ER: M (Marine)
AB: Relative rates of the anaerobic decomposition of organic matter in the upper 10 cm of sediment from two stations in central Long Island Sound, USA, were compared. Sediment samples from discrete depth intervals were incubated anoxically and changes in SOSUB-4SUP-2-, NHSUB-4SUP-+, bacterial numbers, extractable adenosine triphosphate (ATP), organic matter, and organic carbon were measured as a function of time and temperature. At both stations (15 and 34 m water-depths, respectively), the calculated rates of SOSUB-4SUP-2- reduction and NHSUB-4SUP-+ production decreased exponentially with depth. Over the same depth interval, ATP concentrations dropped by a factor of 6-7 and bacterial numbers were lower by a factor of 2-3. These decreases reflect a change in the physiological state of microbial populations with depth in the sediment and are consistent with the conclusions that the quantity of easily utilizable organic matter changes rapidly below the sediment surface and that food limitation controls the basic depth distribution of microbial activity. The average rates of SOSUB-4SUP-2- reduction, 29-39 mM/yr (22 C), in the top 10 cm are similar at both stations studied here, as well as at an additional station from a previous study. In contrast, average NHSUB-4SUP-+ production differs by a factor of 2 at the two stations, reflecting differences in the C:N ratio of the organic matter supplied to the sediment surface and differences in particle reworking by macrofauna at each site.
AN: 0010380
307 of 369
TI: Inorganic transformation of applied phosphorus in brackishwater fish pond soil under different water salinity levels.
AU: Chattopadhyay,G.N.; Mandal,L.N.-(Central-Inland-Fish.-Res.-Inst.,-Barrackpore,-West-Bengal,-India)
SO: Hydrobiologia, 1980 71(1-2), 125-130
LA: English
ER: B (Brackish)
AB: Transformation of applied P was studied as occurring in such ponds, in presence and in absence of added organic matter. Added P disappeared rapidly from the water phase with some variations under different water salinities. The amount of added P in saloid-bound form increased with increase in water salinity but the same in Bray's (No. 2) extractable form showed a reverse trend. Applied P was transformed mostly into insoluble calcium phosphate form which increased with increase in water salinity. Transformation was intermediate into iron phosphate and the least into aluminium phosphate form. Application of organic matter reduced the fixation of added P into the iron phosphate form during the initial period ofstudy and thus increased availability of P both in water as well as soil phases.
AN: 0133460
308 of 369
TI: Bacterial catalysis of the oxidation of manganous manganese in natural waters. Geochemical implications.
OT: Catalyse bacterienne de l'oxydation du manganese manganeux dans les eaux. Consequences geochimiques.
AU: Boulegue,J.; Renard,D.-(Lab.-Geochim.-Eaux,-CNRS-LA-no-196,-Univ.-Paris-VII,-2,-place-Jussieu,-75221-Paris-Cedex-05,-France)
SO: C.-R.-Hebd.-Seances-Acad.-Sci.,-Paris,-Ser.-D, 1980 290(17), 1165-1168
LA: French
ER: M (Marine)
AB: The kinetics of oxidation of manganous manganese in some natural waters is increased 10,000 times as compared with chemical oxidation under abiotic conditions. This is due to bacteria which catalyse the oxidation. The possibility of the presence of such bacteria in the vicinity of mid-oceanic ridges may explain the high deposit rates observed.
AN: 0110420
309 of 369
TI: The geochemical and paleoecological significance of silicon accumulator plants in southeastern salt marshes. /[Presented at:- 44. Annual meeting of the Academy; Tampa, FL (USA); 23 Mar 1980].
AU: Andrejko,M.J.; Cohen,A.D.-(Dep.-Geol.,-Univ.-South-Carolina,-Columbia,-SC-29208,-USA)
CO: /[Presented at:- 44. Annual meeting of the Academy Tampa, FL (USA) 23 Mar 1980].
SO: Fla.-Sci., 1980 43(suppl. 1), 43
NT: Summary only.
LA: English
ER: B (Brackish)
AB: The coastal salt marshes of the southeastern U.S. are basically dominated by two main plants, Spartina alterniflora- in the low marsh, and Juncus roemerianus- in the high marsh. Earlier studies have shown that tidal creek waters in the low marsh become enriched in dissolved silica during low tide discharge. This may be possibly due to the decomposition of plant organic matter and the dissolution of biogenic silicates on the marsh surface. With this in mind, the purpose of this study was to determine the extent to which both Spartina- and Juncus- might behave as reservoirs for future silicon recycling from the decomposition of both in-situ and storm transported plant debris. In addition, the silicon bodies (phytoliths) deposited within the plants themselves were isolated and identified so as to be useful for environmental interpretation of Holocene clayey sediments associated with buried and exposed peat bodies on the Southeastern Coastal Plain.
AN: 0141800
310 of 369
TI: MELIMEX, an experimental heavy metal pollution study: regulation of trace metal concentrations in limno-corrals.
AU: Baccini,P.; Ruchti,J.; Wanner,O.; Frieder,E.-(EAWAG/ETH,-CH-6047-Kastanienbaum,-Switzerland)
SO: Schweiz.-Z.-Hydrol.-Rev.-Suisse-Hydrol.-Swiss-J.-Hydrol., 1979 41(2), 202-227
LA: English
ER: F (Freshwater)
AB: In three limno-corrals of the MELIMEX project the transport paths of the trace metals Cu, Zn, Cd, Hg and Pb and the reaction of the systems on increased metal loads were investigated. The metal balances lead to the conclusion that the biomass is the main factor responsible for the regulation of trace metal concentration. The observed sequence of relative residence times of the trace metals can be described with a steady-state model. Additional metal load decreases the ability of the limnic system to lower the metal concentration. The production of phytoplankton and its assimilation capacity for metals are reduced leading to relatively higher metal concentrations in the lake.
AN: 0005640
311 of 369
TI: Hydrographic features of the deep water of the Bering Sea _ the Sea of Silica.
AU: Tsunogai,S.; Kusakabe,M.; Iizumi,H.; Koike,I.; Hattori,A.-(Hokkaido-Univ.,-Chem.-Dep.,-Hakodata,-Japan)
SO: Deep-Sea-Res., 1979 26(6A), 641-659
LA: English
ER: M (Marine)
AB: The deep water of the Bering Sea contains concentrations of dissolved silicate up to 240 g at. Si/l. Nitrate concentrations are less than in the North Pacific at the depths with the same oxygen contents. The rate of chemical and biochemical reactions occurring in the deep water (below 2 km) were estimated from hydrographic data by applying a modified one-dimensional model. Oxidation of organic matter in the oxygenated water column of the Bering Sea was twice that of the North Pacific. Silicate regeneration, or dissolution of biogenic opal and denitrification, or bacterial nitrate reduction to gaseous nitrogen, on and in the bottom sediments of the deep Bering Sea basin were calculated to be 212 and 20 mg at/mSUP-2/yr, respectively. These values are consistent with the ones estimated from vertical profiles of dissolved silicate and nitrate in the interstitial water of the sediments. The chemical anomaly observed in the deep water of the Bering Sea can be produced by these reactions in the bottom sediments. The decomposition of organic matter in anoxic sediments accounts for about 8% of the total organic matter decomposing in the water column below 2 km and in the sediments.
AN: 0007230
312 of 369
TI: Specificities of the distribution and dynamics of nitrate nitrogen in the waters of the Bulgarian sector of the Black Sea.
AU: Rojdestvensky,A.V.-(Address-not-stated)
SO: Okeanologiya-Oceanology,-Sofia, 1980 vol. 6, 30-36
LA: Bu
ER: M (Marine)
AB: The mean distribution of nitrate nitrogen in the surface waters is presented on the basis of investigtions over many years. The general tendency is decrease of the content with increasing the distance to the shore, though local zones of increased or reduced content are observed depending on hydrological and biological factors. The characteristic seasonal patterns of the distribution are outlined along the vertical. In winter there is deep wedging of the nitrate-containing near-shelf waters in the region of the shore slope and upward pushing of the deep waters containing hydrogen sulphide and contaning no nitrates in the regions situated closer to the central part of the sea. In spring considerable nitrate uptake is observed in the upper photic layers, while the isolines of nitrate nitrogen show a tendency towards sloping position; the denitrification process is intensified in the deep-water layers. In summer the two processes are intensified, especially in the deep-water part remote from the shelf. In autumn there is again an increase of the nitrate content and downward movement of the near-shelf waters. On the basis of the data about the nitrate distribution it may be concluded that the autumn-winter descent and wedging of the near-shelf waters in different depth horizons plays a considerable role in the total vertical circulation of the Black Sea waters.
AN: 0134830
313 of 369
TI: Removal of ~SUP-234~Th from a coastal sea: Funka Bay, Japan.
AU: Minagawa,M.; Tsunogai,S.-(Mitsubishi-Kasei-Inst.-Life-Sci.,-Minami-Ohya,-Machida,-Tokyo-194,-Japan)
SO: Earth-Planet.-Sci.-Lett., 1980 47(1), 51-64
LA: English
ER: M (Marine)
AB: In Funka Bay of Hokkaido, Japan, seawater, suspended matter and settling matter were collected once every month in the summer of 1974. These samples were analyzed for SUP-234Th, a short-lived daughter of dissolved SUP-238U. A pronounced disequilibrium between SUP-234Th and SUP-238U, and a highly variable concentration of SUP-234Th were found. Positive correlation, however, exist among the deficiency of SUP-234Th relative to SUP-238U in seawater, the concentration of particulate SUP-2U3SUP-4Th, the fraction of particulate SUP-234Th to total SUP-234Th in seawater, the total dry weight of suspended matter, and the primary productivity during the month previous to sampling. The specific activity of SUP-234Th for the settling particles (620 170 dpm/g) was nearly equal to that for suspended particles (720 600 dpm/g) but much greater than that for plankton (47 24 dpm/g). These facts suggest that suspended particles are somehow closely related to the removal of heavy metals from seawater, in spite of the negligibly small settling flux of suspended matter. The residence time of thorium in Funka Bay (mean depth: 60 m) is found to be about 60 days, which is nearly equal to those of SUP-210Pb and SUP-210Po.
AN: 0114670
314 of 369
TI: The seasonal variation in the nutrient chemistry of the surface microlayer of Galway Bay, Ireland.
AU: Berry-Lyons,W.; Pybus,M.J.S.; Coyne,J.-(Dep.-Oceanogr.,-Univ.-College,-Galway,-Eire)
SO: Oceanol.-Acta, 1980 3(2), 151-155
LA: English
ER: M (Marine)
AB: Surface microlayer samples and bulk water samples 50 cm below the surface were collected over a 20 month period at three regular stations in Galway Bay, Ireland. Phosphate enrichments coincided with spring phytoplankton blooms while reactive silicate and nitrate enrichments were associated with high chlorophyll a values in the sub-surface water. The data suggest that in Galway Bay, the largest nutrient enrichments in the surface microlayer are caused by biological activity.
AN: 0004970
315 of 369
TI: Biotic and abiotic parameters affecting diversity in modern and ancient benthic diatom assemblages of Florida. /[Presented at:- 43. Annual Meeting of the Florida Academy of Sciences; Miami, FL (USA); 22 Mar 1979].
AU: Defelice,D.; Lynts,G.-(Dep.-Geology,-FSU,-Tallahassee,-FL-32306,-USA)
CO: /[Presented at:- 43. Annual Meeting of the Florida Academy of Sciences Miami, FL (USA) 22 Mar 1979].
SO: Fla.-Sci., 1979 42(1, suppl.), 44
NT: Summary only.
LA: English
ER: M (Marine)
AB: Study of benthic diatom communities in Florida Bay reveals that diversity in living diatom populations is a function of several biotic and abiotic parameters. Among the most important of these parameters is substrate, light quality, sediment particle size, and distance from land. Examination of a core recovered from Florida Bay shows that although diatoms are quite common in surface sediment, they are absent immediately below the surface horizon, leaving sponge spicules as the only siliceous biogenic components in the sediment. Florida Bay, as a shallow water carbonate environment, is extremely undersaturated with respect to silica in the water column and at the sediment-water interface. It is believed that diatoms dissolve almost immediately after death, allowing for quick recycling and reutilization of silica in a silica starved environment. Rapid dissolution and recycling would subsequently impede any accumulation of dissolved silica in interstitial pore waters.
AN: 0129160
316 of 369
TI: Oceanographic distributions of cadmium, zinc, nickel, and copper in the North Pacific.
AU: Bruland,K.W.-(Cent.-Coast.-Mar.-Stud.,-Div.-Nat.-Sci.,-Univ.-California,-Santa-Cruz,-CA-95064,-USA)
SO: Eart-Planet-Sci.-Lett., 1980 47(2), 176-198
LA: English
ER: M (Marine)
AB: Vertical profiles of Cd, Zn, Ni, and Cu have been determined at three stations in the North Pacific and in the surface waters on a transect from Hawaii to Monterey, California. The distributions found are oceanographically consistent and provide a needed confirmation and extension of several recent studies on the marine geochemistries of these metals. Cadmium concentrations average 1.4 pmol/kg in surface waters of the central North Pacific and show a strong correlation with the labile nutrients, phosphate and nitrate, increasing to values of 1.1 nmol/kg at depths corresponding to the phosphate maximum. Zinc is depleted in surface waters of the central gyre to an average value of 0.07 nmol/kg and increases to a deep maximum of 9 nmol/kg exhibiting a strong correlation with the nutrient silicate. Nickel concentrations average 2.1 nmol/kg in surface central gyre waters and increase to a deep maximum of 11 nmol/kg. Nickel is best correlated with a combination of phosphate and silicate. Copper averages less than 0.5 nmol/kg in surface waters of the central North Pacific and increases gradually to values of 5 nmol/kg in bottom waters. The Cu profiles show evidence of intermediate and deep water scavenging. The involvement of these metals in the internal biogeochemical cycles of the sea is responsible for their distributions which are predictable on the basis of oceanographic parameters.
AN: 0115580
317 of 369
TI: [Changes in the salt and biogenic composition of water caused by phenol introduction (an experimental study)].
OT: Izmenenie solevogo i biogennogo sostava vod pri vnesenii fenola (v ehksperimente).
AU: Sinel'-nikov,V.E.; Kudryavtsrva,N.A.; Yagodka,N.L.-(Inst.-Biol.-Vnutr.-Vod.-AN-SSSR,-Borok,-Yaroslav,-Obl.,-USSR)
SO: Gidrobiol.-Zh., 1979 15(6), 101-106
LA: Russian
AB: The formation of the composition of bottom water layers under conditions of continuous introduction of large quantities of phenol (5 mg/l) is analyzed. If the abundance and the species diversity of hydrobionts are not large (sand bottom) the products of the transformation and synthesis of new phenol-based organic substances participate in leaching out the components of the mineral composition of bottom sediments. In the case of a high species diversity of hydrobionts the phenol breaks down to final mineral products.
AN: 0006040
318 of 369
TI: [Experimental approach to the ecological rating of harmful compounds in water bodies].
OT: Ehksperimental'nyj podkhod k ehkologicheskomu normirovaniyu vrednykh veshchestv v vodoemakh.
AU: Kamshilov,M.M.; Yagodka,N.L.-(Inst.-Vnutr.-Vod.-AN-SSSR,-Borok,-USSR)
SO: Gidrobiol.-Zh., 1979 15(6), 85-91
LA: Russian
AB: Studies of the phenol destruction processes in the presence of lead showed that the rate of phenol destruction in the ecosystems of different types was dependent on the concentration of lead. A new approach to the biotesting of pollutants is proposed based on the evaluation of the phenol destruction rate under the influence of toxicants.
AN: 0006010
319 of 369
TI: [On the compensation of anthropogenic CO~SUB-2~ emissions by water and woodland].
OT: Zur Kompensation der anthropogenen CO~SUB-2~-Emission durch Wasser und Wald.
AU: Paucke,H.-(Akad.-Wissenschaft.-DDR,-Inst.-Geogr.-Geooekol.,-Bereich-Oekol.-Oekon.-Syst.,-DDR-1199-Berlin,-Rudower-Chaussee-5,-GDR)
SO: Acta-Hydrophys., 1979 24(1-2), 35-96
LA: German
AB: The paper deals with the question of how far woodland and aquatic ecosystems are able to compensate for anthropogenic COSUB-2-emissions and utilize them for organic matter production. The natural contents of COSUB-2 in air and water and anthropogenic COSUB-2-formation are discussed to show the complicated character and complexity of the problem. Information is given on primary production in terrestrial and aquatic ecosystems and on the multiplicity of interrelations existing between COSUB-2 and primary production. The COSUB-2 cycle is also discussed.
AN: 0088380
320 of 369
TI: Microelements in the Japan Sea ecosystem.
OT: Mikroehlementy v ehkosisteme Yaponskogo morya.
AU: Patin,S.A.; Morosov,N.P.; Romanteeva,A.S.; Mel'-nikova,R.M.; Borisenko,G.S.-(VNIRO,-Moscow,-USSR)
SO: Geokhimiya, ISSN:-0016-7525 1980 (no. 3), 423-429
LA: Russian
ER: M (Marine)
AB: The content and distribution of microelements (Fe, Mn, Zn, Cu, Ni, Pb, Cd and Sr) in water suspension, plankton, fish and phyto- and zoobenthos from the Sea of Japan are considered. Preliminary estimates of average concentrations of microelements are given for separate components of the marine ecosystem.
AN: 0004250
321 of 369
TI: Investigations on the sedimentation in the Darss-Zingst Bodden waters. A contribution to the establishment of an energy and matter balance in the ecosystem. Part 1: Determination of the rate of sedimentation and of production-biologically important parameters of the sedimented material.
OT: Untersuchungen zur Sedimentation in den Darss-Zingster Boddengewaessern _ ein Beitrag zur Aufstellung einer Energie- und Stoffbilanz im Oekosystem. Teil 1: Die Bestimmung der Sedimentationsrate und die Erfassung produktionsbiologisch wichtiger Parameter des sedimentierten Materials.
AU: Nausch-Stengl,M.; *Schlungbaum,G.; Oertzen,J.A.v.-(Sekt.-Biol.,-Fachber.-Meeres-u.-Fischereibiol.,-Wilhelm-Pieck-Univ.-Rostock,-25-Rostock-1,-Freiligrathstr.-7/8,-GDR)
SO: Acta-Hydrochim.-Hydrobiol., 1980 8(1), 59-69
LA: German
ER: M (Marine); B (Brackish)
AB: The sedimented material is characterized by its contents of P and Fe, loss on ignition, chemical oxygen consumption and caloric value. The increase of sediment is estimated at 2.3 cm/s, corresponding to about 1% of the energy of global radiation. The P sedimentation is 3.14 g/mSUP-3a POSUB-4-P, 75% being released again and 0.8 g being retained in the sediment. The oxygen consumption for the reduction from 60 to 30% of substance within the dry matter is 380 mg OSUB-2/g dry matter.
AN: 0103660
322 of 369
TI: The nutrient distribution in sediments of North-German lakes and remarks about the exchange between sediment and pelagic region.
OT: Die Naehrstoffverteilung in Sedimenten norddeutscher Seen und Hinweise auf den Austausch Sediment-Pelagial.
AU: Mothes,G.-(Inst.-Geogr.-und-Geooekol.,-Akad.-Wiss.-DDR,-Bereich-Hydrol.,-1162-Berlin,-Mueggelseedamm-260,-GDR)
SO: Acta-Hydrochim.-Hydrobiol., 1980 8(1), 35-46
LA: German
ER: F (Freshwater)
AB: Nutrient and carbon concentrations in the superficial sediment layers of eight stations in five lakes and in a pond in the Stechlin lake region are discussed. The indicator value of P distribution in the sediment is demonstrated by a comparison between oligotrophic and eutrophic, low-production, high-production and overfertilized waters. Data concerning sedimentation, release and retention of C, N and P yield information concerning the effects of sanitation measures, the reduction of the C:P-ratio and carbon oxidation in the sediment.
AN: 0103650
323 of 369
TI: Geochemistry of sulphur in the bottom sediments of Lake Baikal.
OT: Geokhimiya sery v donnykh otlozheniyakh ozera Bajkal.
AU: Lazo,F.I.-(Limnol.-Inst.-Sibirsk.-Otd.-AN-SSSR,-Listvennichnoe-na-Bajkale,-USSR)
SO: Geokhimiya, ISSN-0016-7525. 1980 (no. 1), 109-115
LA: Russian
ER: F (Freshwater)
AB: Original data on the content of sulphur forms (sulphate, free, sulphide, pyrite and organic) in the sediments are presented and discussed. The data point to a fairly high rate of exchange reactions determined by microbiological processes of sulphate reduction and formation of reduced S forms.
AN: 0004230
324 of 369
TI: A model of amorphous silica accumulation in the bottom sediments of the Pacific Ocean.
OT: Model' nakopleniya amorfnogo kremnezema v donnykh osadkakh Tikhogo okeana.
AU: Bogdanov,Yu.A.; Gurvich,E.G.; Lisitsyn,A.P.-(Inst.-Okeanol.-AN-SSSR,-Moscow,-USSR)
SO: Geokhimiya, ISSN-0016-7525. 1980 (no. 1), 84-92
LA: Russian
ER: M (Marine)
AB: Amorphous silica together with organic carbon in the bottom sediments of the Pacific Ocean is fairly informative for quantitative characterization of the environmental conditions of sedimentation. Accumulation of amorphous silica as well as the amorphous silica-organic carbon ratio in recent bottom sediments of the Pacific Ocean are quantitatively interrelated with the biologic productivity of surface waters and with the ocean depth. A model is proposed which describes well the acumulation of amorphous silica in the areas of the pelagic zone where there is no redeposition of sedimentary material on the bottom.
AN: 0004210
325 of 369
TI: The major-element chemistry of suspended matter in the Amazon Estuary.
AU: Sholkovitz,E.R.; Price,N.B.-(Grant-Inst.-Geol.,-West-Mains-Road,-Edinburgh-EH9-3JW,-UK)
SO: Geochim.-Cosmochim.-Acta, 1980 44(2), 163-171
LA: English
ER: B (Brackish)
AB: Suspended matter from the surface waters of the Amazon Estuary were collected during May and June 1976 on the 'R/V Alpha Helix-', and their major-element compositions (Al, Si, Ti, K, Mg, Ca, P, Fe and Mn) were measured. Between salinities of 0 and 10 o/oo, the suspended material, predominantly terrigenous in derivation, decreases in load from 500 to 3 mg/l, but has a chemical composition which remains essentially constant. With the onset of a large amount of biological productivity at approximately 10 o/oo salinity, there are large increases in the ratios of Si/Al, P/Al, Ca/Al, Mg/Al, Ti/Al and Mn/Al which are maintained at higher salinities. Calculations of 'excess' concentrations of elements held in the non-terrigenous components of the suspended material further support the main conclusion that Si, P, Ca, Mg, Ti and Mn are incorporated into the skeletal and organic phases of marine phytoplankton (predominantly diatoms) of the Amazon Estuary. The data suggest, but with less certainty, that Fe and K follow the above elements. This study has demonstrated that the chemical composition of river-introduced suspended matter can be significantly altered by bioloical activity within estuarine waters as can be the geochemical cycle of inorganic elements.
AN: 0081030
326 of 369
TI: Migration of ~SUP-90~Sr and ~SUP-137~Cs within water - freshwater plant and water - soil systems.
AU: Kulikov,N.V.; Chebotina,M.Ya.; Lyubimova,S.A.-(Inst.-Plant-and-Anim.-Ecol.,-Ural-Sci.-Cent.,-USSR-Acad.-Sci.,-Sverdlovsk,-USSR)
SO: Radiobiologiya, 1980 20(1), 146-148
LA: Russian
ER: F (Freshwater)
AB: Strontium-90 is fixed in stonewort more firmly than in higher aquatic plants: for cesium-137, there is no difference between stonewort and other freshwater plants. Both radioisotopes are sorbed by sapropel and peaty soil better than by sand-silty and lime soils. The poorest isotope fixation was registered in sandy soil.
AN: 0073830
327 of 369
TI: Water column anomalies in dissolved silica over opaline pelagic sediments and the origin of the deep silica maximum.
AU: Edmond,J.M.; Jacobs,S.S.; Gordon,A.L.; Mantyla,A.W.; Weiss,R.F.-(Dep.-Earth-Planet.-Sci.,-Massachusetts-Inst.-Technol.,-Cambridge,-MA-02139,-USA)
SO: J.-Geophys.-Res., 1979 84(C12), 7809-7826
LA: English
ER: M (Marine)
AB: Recent estimates based on pore water studies and mass balance considerations put the average flux of dissolved silica from the sediments into the deep water at about 3 mol cmSUP--2 yrSUP--1. This flux, if mixed uniformly in a bottom layer 100 m thick, results in an anomaly increment of 0.3 mol kgSUP--1 yrSUP--1. In basins of restricted circulation containing opaline sediments the residence time of the bottom waters should be long enough that the resulting anomaly be easily resolvable using existing data. Examination of the many hundreds of detailed, precise silica profiles presently available in unpublished reports shows that this is indeed the case.dian Ocean. The flux of dissolved silica from the sea floor is generally unaccompanied by any resolvable oxygen consumption, indicating that relatively minor amount of organic material reach the sediments in these regions. However, in the north Indian Ocean there are pronounced effects on all the nutrients, oxygen, and alkalinity, with regeneration approximating the Redfield prediction. In the northern Indian Ocean and the extreme northeast Pacific (northeast of 45N, 160W) the silica profiles increase to the bottom. This is a strong indication that the deep silica maximum observed over much of these oceans may have a large adv ective component, the feature itself being induced by the northward flow of the underlying low-silica bottom waters. In the Indian Ocean the data coverage is sufficient to demontrate unequivocally the dominance of this effect.
AN: 0080890
328 of 369
TI: Biogeochemical cycling in an organic-rich coastal marine basine. _ 1. Methane sediment-water exchange processes.
AU: Martens,C.S.; Klump,J.V.-(Mar.-Sci.-Prog.-and-Dep.-Geol.,-Univ.-North-Carolina,-Chapel-Hill,-NC-27514,-USA)
SO: Geochim.-Cosmochim.-Acta, 1980 44(3), 471-490
LA: English
ER: M (Marine)
AB: Methane produced in anoxic organic-rich sediments of Cape Lookout Bight, North Carolina, enters the water column via two seasonally dependent mechansisms: diffusion and bubble ebullition. Diffusive transport measured in situ with benthic chambers averages 49 and 163 mol.mSUP--2.hrSUP--1 during November-May and June-October respectively. High summer sediment methane production causes saturation concentrations and formation of bubbles near the sediment-water interface. Subsequent bubble ebullition is triggered by low-tide hydrostatic pressure release. June-October sediment-water gas fluxes at the surface average 411 ml (377 ml STP; 16.8 mmol).mSUP--2 per low tide. Bubbling maintains open bubble tubes which apparently enhance diffusive transport. When tubes are present, apparent sediment diffusivities are 1.2-3.1-fold higher than theoretical molecular values reaching a peak value of 5.2 x 10SUP--5 cmSUP-2.secSUP--1. Dissolution of 15% of the rising bubble flux containing 86% methane supplies 170 mol.mSUP--2.hrSUP--1 of methane to the bight water column during summer months; the remainder is lost to the troposphere. Bottom water methane concentration increases observed during bubbling can be predicted using a 5-15 m stagnant boundary layer dissolution model. Advective transport to surrounding waters is the major dissolved methane sink; aerobic oxidation and diffusive atmospheric evasion losses are minor within the bight.
AN: 0074300
329 of 369
TI: Modelling sedimentary systems and their vertical exchanges. /[Presented at:- Society for General Microbiology Symposium on the Microbiology of Sediments; Cambridge (UK); 27 Mar 1980].
AU: Billen,G.-(Lab.-Oceanogr.,-Univ.-Brussels,-Belgium)
CO: /[Presented at:- Society for General Microbiology Symposium on the Microbiology of Sediments Cambridge (UK) 27 Mar 1980].
SO: Soc.-Gen.-Microbiol.-Q., 1980 7(2), 67
NT: Summary only.
LA: English
AB: Evaluating the rates of microbiological processes in biogeochemical cycles and understanding the factors controlling them, are often the final aims of ecological studies of the microbiology of sediments. For these two purposes, mathematical modelling in combination with other methods for determining rates of microbial activities, can be very helpful. Modelling the vertical distribution of the concentration of some chemical species within the sedimentary column allows one to use this kind of statical data for deducing dynamical information such as rates of production or consumption of this species and exchange flux across the sediment-water interface. When some particular regulation mechanism is postulated or experimentally demonstrated, diagenetic models can be used for simulating its overall effect on the whole sedimentary system and their vertical exchanges. This contribution gives a general presentation of the techniques commonly used in such models, along with several illustrations of the usefulness of this approach in studying nitrogen recycling in North Sea sediments.
AN: 0046940
330 of 369
TI: [Preface to special issue on geobiochemical investigations in the Zaire river, estuary and plume].
AU: Eisma,D.-(Netherlands-Inst.-Sea-Res.,-Texel,-The-Netherlands)
SO: Neth.-J.-Sea-Res., 1979 12(3-4), 253-254
NT: Special issue: geobiochemical investigations in the Zaire river, estuary and plume.
LA: English
ER: M (Marine); B (Brackish)
AB: In November 1976 a research programme was carried out in the Zaire (Congo) river estuary and the adjacent ocean. This was the first part of a project to investigate the contribution of the Zaire river to the ocean, to study its outflow and the physical and chemical processes involved, and to study the deposition of Zaire river material on the floor of the Angola Basin. The Zaire was selected as it is the second largest river in the world, and because little was known about the river and its chemistry. A second programme was carried out in April and May 1978 and a third programme, mainly concerning the ocean bottom deposits, will be carried out in 1980. In this issue the results of the November 1976 programme are presented together with the salinity, temperature and nutrient data obtained in April and May 1978 which became available while this issue was in preparation. The project, sponsored by the Committee on Oceanic Research of the Netherlands Academy of Sciences, was made possible by the financial support of the Netherlands Ministry of Education and Sciences and by the cooperation of the Zairean Government which gave permission to carry it out within the territorial waters of Zaire. Contributions are catalogued separately in ASFA 1 and 2.
AN: 0008830
331 of 369
TI: Marine biota, nearshore sediments, and the global carbon balance.
AU: Deuser,W.G.-(Woods-Hole-Oceanogr.-Inst.,-Woods-Hole,-MA-02543,-USA)
SO: Org.-Geochem., 1979 1(4), 243-247
LA: English
ER: M (Marine)
AB: Nearshore waters to a depth of 200 m constitute only 0.2% of the volume of the world's oceans, but they receive and process 25% of the oceans' input of organic carbon, between 6 and 7 x 10SUP-15 g C per year. Man's activities during the past century have significantly increased both the supply of nutrients from land to coastal waters and the total sediment load carried by rivers and deposited in nearshore waters. The combination of increased primary productivity, due to increased supply of nutrients, and increased burial of organic matter, due to increased sedimentation, could sequester a significant fraction of the carbon released into the atmosphere by man as organic carbon in recent shallow-water sediments.
AN: 0038280
332 of 369
TI: Volatile organic sulfides from freshwater algae.
AU: Bechard,M.J.; *Rayburn,W.R.-(Dep.-Bot.,-Washington-State-Univ.,-Pullman,-WA-99164,-USA)
SO: J.-Phycol., 1979 15(4), 379-383
LA: English
ER: F (Freshwater)
AB: Dimethyl sulfide (DMS) was found to be the principle biogenic sulfur compound in a freshwater environment. Endemic and non-endemic algae were cultured under axenic and nonaxenic conditions in defined media. Sulfur gas analysis of culture fluids indicated that Cyanophyta were probable sources of DMS whereas representatives of Chlorophyta, Xanthophyta and Bacillariophyta apparently did not produce this compound. Comparison of gaseous contents of young and old nonaxenic cultures of filamentous Chlorophyta and Xanthophyta showed DMS occurred only in aged cultures and was probably produced by bacteria utilizing substances from senescent algal cells. Data suggest that the composition of the algal community determines whether DMS is algal and/or bacterial in origin.
AN: 0044620
333 of 369
TI: Kinetics of nutrient regeneration in anoxic marine sediments.
AU: Berner,R.A.-(Dep.-Geol.-Geophys.,-Yale-Univ.,-New-Haven,-CT-06520,-USA)
SO: Phys.-Chem.-Earth, 1979 11, 279-292
LA: English
ER: M (Marine)
AB: Anoxic sediments undergoing bacterial sulfate reduction, because of the buildup in them of dissolved ammonia and phosphate from the decomposition of organic matter, may serve as important sources of these nutrients for the oceans. This paper demonstrates how pore water concentration-vs-depth data, along with laboratory measurements, can be combined with theoretical models to deduce rates and rate laws for nutrient release and bacterial sulfate reduction in sediments. Further application of the models enables determination of the stoichiometric C:N:P composition of the organic matter undergoing decomposition and the fraction of liberated nutrient which is returned to the overlying water. For an anoxic sediment from Long Island Sound, USA, diagenetic modeling of pore water data showed that rates of organic N and P decomposition and of microbial sulfate reduction, below the top few cm of sediment, is first order with respect to the organic matter being decomposed. Application of the first-order rate law to a variety of other sediments reviewed a direct proportionality between the rate constant for sulfate reduction and the square of the rate of deposition. Also, decomposition rates calculated from modeling are in good agreement with rates measured in the laboratory using the same sediment. In the upper portion of anoxic sediments overlain by oxygenated water, higher concentrations of more readily metabolized organic matter are found, and migration of dissolved constituents is enhanced due to irrigatin and other modes of mixing by benthic organisms (bioturbation).
AN: 0023500
334 of 369
TI: [Preface to special issue on geobiochemical investigations in the Zaire river, estuary and plume].
AU: Eisma,D.-(Netherlands-Inst.-Sea-Res.,-Texel,-Netherlands)
SO: Neth.-J.-Sea-Res., 1979 12(3-4), 253-254
NT: Special issue: Geobiochemical investigations in the Zaire river, estuary and plume.
LA: English
ER: M (Marine); B (Brackish)
AB: In November 1976 a research programme was carried out in the Zaire (Congo) river estuary and the adjacent ocean. This was the first part of a project to investigate the contribution of the Zaire river to the ocean, to study its outflow and the physical and chemical processes involved, and to study the deposition of Zaire river material on the floor of the Angola Basin. The Zaire was selected as it is the second largest river in the world, and because little was known about the river and its chemistry. A second programme was carried out in April and May 1978 and a third programme, mainly concerning the ocean bottom deposits, will be carried out in 1980. In this issue the results of the November 1976 programme are presented together with the salinity, temperature and nutrient data obtained in April and May 1978 which became available while this issue was in preparation. The project, sponsored by the Committee on Oceanic Research of the Nethelands Academy of Sciences, was made possible by the financial support of the Netherlands Ministry of Education and Sciences and by the cooperation of the Zairean Government which gave permission to carry it out within the territorial waters of Zaire. Contributions are catalogues separately in ASFA 1 and 2.
AN: 0008830
335 of 369
TI: Atmospheric contributions to stream water chemistry in the North Cascade Range, Washington.
AU: Dethier,D.P.-(U.S.-Geol.-Surv.,-Seattle,-WA-98105,-USA)
SO: Water-Resour.-Res., 1979 15(4), 787-794
LA: English
ER: F (Freshwater)
AB: Bulk precipitation contributes significant quantities of cations and trace metals to a subalpine catchment located in the North Cascade Range of Washington. Precipitation loadings accounts for 30% of the major and >50% of the minor element export from the catchment. Preliminary data from larger basins in the North Cascades suggest similar values. Calcium and potassium measured in bulk precipitation are largely derived from continental dusts, while sodium and magnesium originate as marine aerosols. Lead, copper, and arsenic, products of anthropogenic activity in the Puget Lowland, are deposited downwind in the Cascade Mountains; mean precipitation pH at the study site was 4.85 during 1974 and 1975. Elements contributed by precipitation become part of complex upland biogeochemical cycles. With the exception of highly mobile ions like sodium, elemental levels in streamflow reflect biologic and pedogenic cycling processes rather than direct precipitation influence.
AN: 0007290
336 of 369
TI: The coordinated Mediterranean Pollution Monitoring and Research Program.
AU: Keckes,S.-(UNEP,-Palais-de-Nations,-CH-1211-Geneva-10,-Switzerland)
SO: Ambio, 1977 6(6), 327-328
LA: English
ER: M (Marine)
AB: Seven pilot projects were originally approved at the 1975 Intergovernmental Meeting in Barcelona as part of the Mediterranean Pollution Monitoring and Research Program (MED POL). Four of them are basically monitoring activities, although all have a strong research orientation. The monitoring is based on very precise sampling and analytical procedures as well as on permanent intercalibration techniques. This leads to comparable data from the whole Mediterranean. The original seven pilot projects of the MED POL deal mainly with the coastal waters of the Mediterranean, and therefore an additional pilot project dealing with pollution levels of the open waters and the biogeochemical cycles of the most important pollutants was later initiated in cooperation with IAEA and IOC.
AN: 9177270
337 of 369
TI: [Data on the atmospheric cycle of marine salts].
OT: Donnees sur le cycle atmospherique des sels marins.
AU: Morelli,J.-(Mission-Rech.,-Ministere-Environ.-Cadre-de-Vie,-14-Bd-General-Leclerc,-92521-Neuilly-sur-Seine,-France)
SO: J.-Rech.-Oceanogr., 1978 3(4), 27-50
LA: French
ER: M (Marine)
AB: This paper uses results presented in a thesis (Morelli, 1977). Although investigations concern generally four components of atmospheric aerosol which are the most abundant cations in sea water _ Na, K, Ca, Mg _, attention is focused on the case of potassium, element of a great interest for biosphere. Research was carried out in a large scale view. It has taken into account observations at different levels of the atmospheric link of considered elements biogeochemical cycle: injection into air by oceanic bubbling, study of their distribution close to the sea surface in various marine regions and of their vertical distribution, deposition on ocean and continents. An estimation of potassium fluxes magnitude injected in the atmospheric reservoir from different natural and anthropogenic sources is given. The question of cyclic supply of marine potassium to continents and its geochemical implications is discussed.
AN: 9005130
338 of 369
TI: Mechanisms for detrital cycling in nearshore waters at Bermuda.
AU: Welsh,B.L.; Bessette,D.; Herring,J.P.; Read,L.M.-(Mar.-Sci.-Inst.,-Univ.-Connecticut,-Avery-Point,-Groton,-CT-06340,-USA)
SO: Bull.-Mar.-Sci., 1979 29(2), 125-139
LA: English
ER: M (Marine)
AB: The detrital cycle in Whalebone Bay and adjacent coastal waters at Bermuda was investigated to determine how such a relatively open system of exchanges of nutrients and carbon could be maintained in the highly oligotrophic waters which bathe the island. The shore zone and particularly the beach wrack were found to provide a source of materials, and a stranding cycle is described whereby detrital seagrasses and algae are insolated, desiccated, and leached, accelerating the release of dissolved constituents and fine particulates to the water column. Three conservative processes associated with the embayment were noted: tidal recycling of nearshore water, the delaying effects of oscillatory wave motion, and biological uptake by benthic plants which served to reduce exports and retain both nutrients and organic carbon within the Bay, thereby perpetuating the cycle. Little if any particulate material left the Bay. In fact, substantial quantities of C, N, and P were imported from the Sargasso Sea in the form of Sargassum- which more than compensated for any exports. Thus a relatively open detrital system does operate in Bermuda, maintained and perpetuated by a combination of physical, chemical, and biological processes and subsidized from the open ocean, but its influence is confined to a narrow band near shore.
AN: 9113500
339 of 369
TI: Balance of biogenous elements in the Caspian Sea during the period of regulated streamflow runoff.
AU: Maksimova,M.P.; Katunin,D.N.; Yeletskiy,B.D.-(Address-not-stated)
SO: Oceanol.-Acad.-Sci.-USSR, 1978 18(3), 295-297
LA: English
ER: M (Marine)
AB: Calculations of the balance of biogenous elements in the Caspian Sea during th period of regulated streamflow show that their main source is continental runoff (about 70% of nitrogen, 90% of phosphorus, 95% of silicon), that submarine ground-water runoff accounts for about 15% of nitrogen, 10% of phosphorus, and 5% of silicon, and that about 15% of the nitrogen are supplied from the atmosphere. The long-period mean total supply of these elements to the Caspian is: 40,700 metric tons of total phosphorus, 607,000 metric tons of total nitrogen (including about 20% dissolved mineral phosphorus and 50% dissolved mineral nitrogen); and 750,000 metric tons of dissolved silicon. The annual supply varies within 26,300-55,100 metric tons of total phosphorus, 389,000-904,000 metric tons of total nitrogen, and 400,000-1,230,000 metric tons of phosphorus, 590,000 metric tons of nitrogen, and 730,000 metric tons of silicon. The losses due to fishery amount to about 4% of phosphorus and 2% of nitrogen.
AN: 9118460
340 of 369
TI: Uptake of americium-241 by algae and bacteria.
AU: Giesy,J.P.,Jr.; Paine,D.-(Savannah-River-Ecol.-Lab.,-Drawer-E,-Aiken,-SC-29801,-USA)
SO: Prog.-Water-Technol., 1977 9(4), 845-857
LA: English
AB: The availability of SUP-241Am to algae and bacteria was studied to elucidate their role in determining the ultimate fate of SUP-241Am released into the environment. It was found that both algae and bacteria concentrate SUP-241Am to a high degree, which makes them potentially important in biomagnification, as well as cycling the element in the water column and mobilisation from the sediments. Chemical fixation of algal cells caused an increased uptake of SUP-241Am, which indicates that uptake is by passive diffusion. Increased uptake, after fixation, is probably due to chemical alteration of surface binding sites. This problem may be eliminated by killing algal cells used in uptake studies by u.v. light.
AN: 9091810
341 of 369
TI: Biological release and recycling of toxic metals from lake and river sediments.
AU: Nicholas,W.L.; Thomas,M.-(Dep.-Zool.,-Australian-Natl.-Univ.,-Canberra,-2600-ACT,-Australia)
SO: Aust.-Water-Resour.-Counc.-Tech., 1978 (no. 33), 1-99
LA: English
ER: F (Freshwater)
AB: The Molonglo River, NSW, Australia, has been polluted with heavy metal wastes from mines, now abandoned, on the banks of the river. Pollution has almost eliminated animals and plants from the river bed for many kilometres downstream. Great quantities of zinc are present in the river system. Organic detritus has firmly bound very high concentrations of zinc and animals and plants have very high concentrations of zinc in their tissues. Microbial films accumulated high concentrations of heavy metals and microscopic nodules rich in zinc and copper or iron, manganese, with lesser amounts of other metals have developed on substrates over several months. Bullrushes and willows take up zinc from the river sediments, and their dead leaves retain zinc until they disintegrate. Dead bullrush leaves continue to absorb zinc from the river water and from the river sediments. Microorganisms, predominately algae, also absorb zinc from river water and retain zinc in zinc-free water. Invertebrates feeding on the detritus and microorganisms ingest zinc in their food, retaining some in their tissues, but excrete much with their faeces.
AN: 9079820
342 of 369
TI: Copper in the marine environment _ Part 2.
AU: Schmidt,R.L.-(Battelle-Mem.-Inst.,-Richland,-WA-99352,-USA)
SO: C.R.C.-Crit.-Rev.-Environ.-Control, 1978 8(3), 247-291
LA: English
ER: M (Marine)
AB: Adsorption appears to have the strongest influence on Cu added to the sea from freshwater sources. Freshly formed hydrous oxides of Mn and Fe and organic matter form thin films on clay particles and may play a dominant role in adsorption. Precipitation may be an important process only in anoxic waters. The accumulation of Cu in sediments appears to be a two-component process. Copper associated with lithic materials is sedimented in proportion to clay deposition. The second component consists of Cu adsorbed from the water column during transport or Cu associated with biotic debris. The uptake of soluble Cu by plankton is the principal pathway for entry of the metal into the food web, although ingestion of Cu-containing nonbiotic particulates may also lead to Cu accumulation by marine organisms. Mobilization of Cu from suspended matter and sediments occurs when Cu-containing organic matter of CuS is oxidized or Cu is desorbed due to dilution or is complexed to form soluble compounds with inorganic and organic ligands. Sediment microbiota affect the biogeochemistry of Cu by influencing the kinetics and thermodynamics of reactions, releasing metabolites that bond with Cu, and catalyzing the oxidation-reduction of metals in sediments.
AN: 9070950
343 of 369
TI: Carbon dioxide - a global environmental problem into the future.
AU: Wong,C.S.-(Ocean-Chem.-Div.,-Inst.-Ocean-Sci.,-Sidney,-British-Columbia,-Canada)
SO: Mar.-Pollut.-Bull., 1978 9(10), 257-264
LA: English
ER: M (Marine)
AB: The author believes that all other forms of pollution are dwarfed by the scale of the invisible pollutant, carbon dioxide, resulting from energy use pattern. Given the considerable climatic effects of COSUB-2 increase in the atmosphere there has not been sufficient resources addressed to this problem. The relationship between COSUB-2 in the atmosphere with wood and fossil fuel burning, changes in soil and land (eg. agriculture, desertification), and natural biological processes (eg. respiration of ocean biota) are discussed. Necessary future remedies are outlined. The author recommends: (1) Techniques of observing oceanic partial pressure of COSUB-2 and other carbonate chemistry parameters should be improved; (2) Efforts to man available open ocean platforms to establish COSUB-2 increase should be intensified; (3) An intensification in the effort to understand oceanic processes of COSUB-2 uptake and release through controlled experiments; and (4) An intensification of work on the physical circulation in the ocean.
AN: 9066170
344 of 369
TI: On the role of the atmosphere in biogeochemical cycles.
AU: Bolin,B.-(Dep.-Meteorol.,-Univ.-Stockholm,-Stockholm,-Sweden)
SO: Quart.-J.-R.-Meteorol.-Soc., 1979 105, 25-42
LA: English
ER: M (Marine)
AB: Of particular concern is an understanding of the basic biogeochemical mechanisms that maintain a quasi-equilibrium; of the extent to which the system may be sensitive to disturbances; and of the way in which the equilibrium may then change. This presentation attempts to emphasize some important general principles and to discuss also some specific questions, such as the likely further increase of carbon dioxide in the atmosphere, the sulphur cycle and the acidity of rain, and the nitrogen cycle and agriculture, since they are much debated at this time.
AN: 9069300
345 of 369
TI: Biological control of dissolved aluminium in seawater: experimental evidence.
AU: Stoffyn,M.-(Bedford-Inst.-Oceanogr.,-Dartmouth,-N.S.-B27-4A2,-Canada)
SO: Science-Wash., 1979 203(4381), 651-653
LA: English
ER: M (Marine)
AB: Experimental evidence supports the hypothesis that the concentration and distribution of dissolved aluminium in ocean water are controlled by biological activity in the surface waters. The growth of the diatom Skeletonema costatum- in artificial seawater media spiked with aluminium reduced the aluminium concentration to that actually found in surface open ocean waters (about 0.5 micrograms per liter). Furthermore, aluminium had a catalytic and limiting effect on the growth of the diatoms.
AN: 9051350
346 of 369
TI: Distribution of stable organic molecules in the marine environment: physical chemical aspects. Chlorinated hydrocarbons.
AU: Dexter,R.N.; Pavlou,S.P.-(URS-Company,-Seattle,-WA-98121,-USA)
SO: Mar.-Chem., 1978 7(1), 67-84
LA: English
ER: M (Marine)
AB: The relative concentrations of non-polar organic compounds in seawater and suspended particulate matter can be explained by an equilibrium sorption mechanism. The value of the quasi-equilibrium constant, K, was calculated with reasonable accuracy for polychlorinated biphenyls from a relatively simple equation which relies on both measurable physical parameters and a number of molecular terms estimated from fundamental physical chemical considerations. This model represents an approach to defining the accumulation of stable organic molecules on marine particulate interfaces within a coherent theoretical framework. As such, it provides a guide for selecting appropriate ecosystem parameters which influence the distribution and accumulation potential of these chemicals in the marine environment.
AN: 9031150
347 of 369
TI: Chemical exchange across sediment-water interface.
AU: Lerman,A.-(Dep.-Geol.-Sci.,-Northwestern-Univ.,-Evanston,-IL-60201,-USA)
SO: Ann.-Rev.-Earth-Planet.-Sci., 1978 6, 281-303
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Fluxes of chemical species across the sediment-water interface are generated by (a) deposition of sediments, (b) growth of the sediment-pore-water column taking place in the course of deposition, and (c) diffusion in pore waters. For different chemical species, the relative importance of each of the three fluxes depends on the nature and type of chemical reactions between solids and solution. When uptake or adsorption from solution is strong, the flux on solids usually predominates over the two other modes of transport. When the rate of sedimentation is slow, then the diffusional fluxes (provided concentration gradients exist) can be the main transport mechanism upward or downward across the sediment-water interface. For those chemical species, concentrations of which in sediment pore waters are affected by biochemical reactions (sulfate, bicarbonate, phosphate, and nitrogen species), the fluxes into or out of sediments are approximately directly related to the sedimentation rates. A global geochemical role of the oeanic sediment-water interface is reflected in the amount of materials, such as biogenic calcium carbonate and silica, that are being regenerated to ocean water during their residence time at the interface. Of the total of biogenic skeletal materials reaching the ocean bottom, significant fractions dissolved before burial in sediments. In general, regeneration of biogenic materials at the sediment-water interface can significantly affect the chemical composition of overlying water and it can be, in human terms, environmentally harmful when relatively large quantities of material dissolve, oxidize, or decay in a relatively small volume of water, such as in seasonally stratified eutrophic lakes.
AN: 9037590
348 of 369
TI: Lead in the environment.
AU: Swaine,D.J.-(CSIRO-Fuel-Geosci.-Unit,-North-Ryde,-N.S.W.-2113,-Australia)
SO: J.-Proc.-R.-Soc.-NSW, 1978 111(1-2), 41-47
LA: English
AB: Various aspects of the geochemistry of lead are discussed in terms of the geochemical cycle. Values are given for concentrations of lead in rocks, soils, water, vegetation, coals, and fertilisers. Lead tends to be concentrated in surface soils, probably because of the insolubility of the common lead minerals and of the lead complexed with some forms of organic matter. The same properties also govern the general unavailability of lead to plants and the low concentrations of lead in natural waters. Lead in solution in waters and lakes also depends on reactions at the sediment-water interface and on the pH and oxidation-reduction potential. The mean content of lead in coal is about 10 ppm Pb, and most of this is retained with fly-ash after the combustion of pulverised coal. The sources of lead in the body are also discussed. Pollution is seen as something imposed on a natural background; the proper assessment of the effects of lead and other heavy metals depends on reliable geochemical data and on careful interpretation.
AN: 9035840
349 of 369
TI: Props and actors on a massive stage.
AU: Mortimer,C.H.-(Center-for-Great-Lakes-Studies,-Univ.-Wisconsin-Milwaukee,-3203-N-Downer,-WI-53201,-USA)
SO: Nat.-Hist.-N.Y., 1978 87(7), 51-58
LA: English
ER: F (Freshwater)
AB: The geochemical characteristics of the Great Lakes basin is outlined, and the seasonal cycle described in detail. During winter the waters are well stirred by wind and wave action and cool down to several degrees below the 40 F temperature of maximum density. As the water warms up in the early spring however thermal stratification develops and terminates the mixing. Illuminated by spring sunshine, microscopic algae photosynthesize to become the initial crop of 'grass' which then nourishes a community of zooplankton. The rate of photosynthetic production is largely controlled by the ratio of 2 depths: the depth from the surface to which photosynthetically usable light energy penetrates and the depth from the surface to which active turbulent stirring is maintained by winds and currents. Soon after stratification has become fully established across the open waters of the lakes essential nutrients in surface offshore waters become progressively depleted because algal growth is limited to the surface illuminated layer and nutrient replenishment from below is impeded at the thermocline. Production continues until late September when the thermocline has sunk below the level at which sufficient light remains. All parts of the food chain interact concurrently. In addition detritus of the living matter is recycled. Aquatic cycles often have some degree of vertical separation of the phases of production and breakdown, due to the combined effects of stratification gravity and vertical variation in intensity of turbulent transport and confinement of most primary production to surface illuminated layers. It is concluded that in general, the Great Lakes ecosystem has survived quite well despite the various and sometimes conflicting uses humans have made of the lakes' resources. Recommendations for future management of these resources is discussed.
AN: 9029200
350 of 369
TI: Hydrocarbons and petroleum in the marine ecosystem - a review./[Presented at-: Petroleum hydrocarbons in the marine environment (ICES Workshop); Aberdeen (UK); 9 Sep 1975].
AU: Hardy,R.; Mackie,P.R.; Whittle,K.J.-(Torry-Res.-Stn.,-P.O.Box-31,-135-Abbey-Road,-Aberdeen-AB9-8DG,-UK)
CO: /[Presented at-: Petroleum hydrocarbons in the marine environment (ICES Workshop) Aberdeen (UK) 9 Sep 1975].
SO: Rapp.-P.-V.-Reun.-Cons.-Int.-Explor.-Mer. 1977 171, 17-26
LA: English
ER: M (Marine)
AB: Various aspects concerning the presence of petroleum in the marine ecosystem are discussed. It is clear from a review of the literature that there is no simple method of determining accurately the amount of petroleum in the ecosystem, especially in the open seas where the concentrations are low. The subsequent fate of the petroleum components is not known although studies have shown that they may be removed or converted into other components by physical, chemical and biological (biochemical) means. Nevertheless, the amounts of petroleum compounds present in the environment appear to exceed the estimated annual input by several orders of magnitude. This may be a reflection of the size of other non-petroleum inputs, erroneous calculations of the size of the petroleum input and/or a greater stability of the petroleum-like components in the ecosystem. The effects caused by petroleum vary not only with the composition and concentration of the petroleum but also with the interacting component. Such effects can be observed most readily where large spillages have occurred. At lower input levels, especially at concentrations found in the open sea, the effects caused by the various petroleum components are not well known and merit a more detailed study.
AN: 8185230
351 of 369
TI: Application of four input-output models for nutrients in Lake Okeechobee, Florida.
AU: Miller,R.L.-(US-Geol.-Surv.,-Denver,-CO,-USA)
SO: J.-Res.-US-Geol.-Surv., 1978 6(6), 821-828
LA: English
AB: R.A. Vollenweider's (1975) nonconservative model described concentrations of nitrogen and phosphorus for 1969-70 in Lake Okeechobee, Florida, better than the models of F. Biffi in 1963, R.H. Rainey in 1967, and R. Piontelli and V. Tonolli in 1964. Vollenweider's model predicted concentrations of 1-.-4 mg/L of total nitrogen and 0-.-09 mg/L of total phosphorus in the lake. The concentration of nitrogen could be approximated with conservative models but phosphorus required a nonconservative model. Unless variations in input concentrations and flow rate of the tributaries are modeled, only short-term predictions of lake concentrations can be made because of variations in inflow concentrations and because of the short time required (400 days) for the lake to be flushed by its inflow.
AN: 9008180
352 of 369
TI: [On the problem of the formation of natural waters chemical composition].
OT: K probleme formirovaniya rhimicheskogo sostava prirodnykh vod.
AU: Samarina,V.S.-(Address-not-stated)
SO: Vesn.-Leningr.-Univ.,-Ser.-Biol., 1977 (no. 18), 63-70
LA: Russian
ER: M (Marine); F (Freshwater)
AB: The main process of formation of the chemical composition of natural water is examined on the basis of circulation of natural waters. The discussional character of the problem of the formation of deep chloride-calcic brines is stated. The conclusion about the genetic non-uniformity of brines and the necessity of detailed studies to understand the natural system : rock-water-gas-living substance is also made.
AN: 9008360
353 of 369
TI: Future research problems in marine organic chemistry.
AU: Gagosian,R.B.; Ahmed,S.I.; Farrington,J.W.; Lee,R.F.; Mantoura,R.F.C.; Nealson,K.H.; Packard,T.T.; Reinhart,K.L.,Jr.-(Dep.-Chem.,-Woods-Hole-Oceanogr.-Inst.,-Woods-Hole,-MA-02543,-USA)
SO: Mar.-Chem., 1978 6(4), 375-382
LA: English
ER: M (Marine)
AB: In June 1977, several marine scientists participated in a workshop sponsored by the National Science Foundation Office for the International Decade of Ocean Exploration. The objective of this meeting was to identify promising opportunities in chemical oceanographic research of the 1980's. The workshop was divided into subsections, one of which was 'Marine Organic Chemistry and Associated Biochemical Problems'. Although some of the recommendations of this subsection were included in an overall report, a more detailed, unified report dealing solely with this topic was deemed necessary and is discussed as follows: (A) Production (1) pelagic; (2) benthic; (B) Transport (1) circulation; (2) vertical flux and resuspension; (C) Transformations (1) environmental effects; (2) upwelling zones; (3) oxygen minimum zones; (4) organic-metallic complexes in the sea; (5) organic mineral phase interactions; and (6) macromolecular compound formation.
AN: 9002080
354 of 369
TI: The dissolved mineral composition of the water flowing into and out of the Hartbeespoort Dam.
AU: Toerien,D.F.; Walmsley,R.D.-(Inst.-Environ.-Sci.,-Univ.-Orange-Free-State,-Bloemfontein,-9301,-South-Africa)
SO: Water-S.A., 1978 4(1), 25-38
LA: English
ER: F (Freshwater)
AB: A two year analytical survey was conducted of the waters flowing into and out of the Hartbeespoort Dam. The Crocodile River was the main source of water and chemical input to the dam, contributing from 88 to 99% of the dissolved mineral input. The concentrations of dissolved minerals in the inflowing waters were highest during the winter dry weather flow and lowest during the summer rainfall period. The mineral content of waters from the outflow of the dam was not subject to the same variation. Considerable quantities of dissolved nitrogenous and phosphate compounds disappear from the water in the dam either through biological or chemical conversions.
AN: 8007860
355 of 369
TI: Experimental measurements of nitrogen remineraliztion in coastal waters.
AU: Harrison,W.G.-(Mar.-Ecol.-Lab.,-Bedford-Inst.-Oceanogr.,-Dartmouth,-NS-B2Y-4A2,-Canada)
SO: Limnol.-Oceanogr., 1978 23(4), 684-694
LA: English
ER: M (Marine)
AB: Ammonium remineralization was measured in the euphotic zone of two coastal areas using a -SUP-15-N isotope dilution technique. Remineralization fluxes were high in both areas and often exceeded assimilation fluxes. A strong positive correlation between ammonium remineralization and ammonium and carbon dioxide assimilation suggests a close coupling of photo-synthesis and nitrogen recycling. Regenerative fluxes decreased with depth and with distance offshore, but to a relatively lesser extent than did assimilative fluxes. Turnover times for remineralization of utilizable organic nirogen were estimated to be from 3 to 16 days. Size fractionation experiments and estimates from the literature suggest that microplankton (<183 -mu-m) may have been the primary nitrogen remineralizers.
AN: 8171430
356 of 369
TI: Studies of Hawaiian freshwater and soil algae. 2. Algal colonization and succession on a dated volanic substrate.
AU: Carson,J.L.; Brown,R.M.,-Jr.-(Dep.-Bot.,-Univ.-North-Carolina,-Chapel-Hill,-NC-27514,-USA)
SO: J.-Phycol., 1978 14(2), 171-178
LA: English
ER: F (Freshwater)
AB: Spatial studies of colonization and succession of soil algae and chemical analyses of the various soils on the cinder cone of Kilauea Iki in Hawaii Volcanoes National Park, Hawaii are outlined. There is a positive correlation between the diversity and quantity of soil algae with nutrient levels and organic matter accumulation in each locale. Three distinct edaphic-biotic zones existing in this area are differently revealed by the soil chemical composition, quantity and diversity of soil algae, and as evident variations in higher plant growth and colonization. Varying colonization and successional phases of higher plant growth around standing and fallen tree snags killed by volcanic activity also reflect variations in the soil algal flora. These variations appear largely as a function of differential water interception, absorption, and retention as well as differential accumulation of organic matter, and the initiation of various biogeochemical cycles.
AN: 8174600
357 of 369
TI: Some observations on the stable carbon isotope composition of dissolved and particulate organic carbon in the marine environment.
AU: Eadie,-B.J.; Jeffrey,-L.M.; Sackett,-W.M.-(Dep.-Oceanogr.,-Texas-A-and-M-Univ.,-College-Station,-TX-77843,-USA)
SO: Geochim.-Cosmochim.-Acta, 1978 42(8), 1265-1269
LA: English
ER: M (Marine)
AB: -delta--SUP-13-C-SUB-PDB- compositions for 39 samples of dissolved organic carbon (DOC) from the Gulf of Mexico-Caribbean Sea-Atlantic Ocean system, the South Pacific and Ross Sea are reported. Deep water values are similar with a mean of -21-.-8-SUP-o-/-SUB-oo- attesting to the homogeneity of the oceanic DOC pool. In Antarctic waters, a 5-SUP-o-/-SUB-oo- difference between DOC and particulate organic carbon (POC), with POC having values similar to modern plankton (-delta--SUP-13-C-SUB-PDB- approx -27-SUP-o-/-SUB-oo-) supports the idea of the transient nature of POC as compared to DOC. Total, lipid, acid hydrolyzed, amino acid and residue fractions of POC are about 5, 3, 7, 5 and 3-SUP-o-/-SUB-oo- respectively, more negative in 2000 m water as compared to surface water samples from the Gulf of Mexico.
AN: 8160460
358 of 369
TI: Cadmium in northeast Pacific waters.
AU: Bruland,-K.W.; Knauer,-G.A.; Martin,-J.H.-(Cent.-Coastal-Mar.-Stud.,-Div.-Nat.-Sci.,-Univ.-California,-Santa-Cruz,-CA-95064,-USA)
SO: Limnol.-Oceanogr., 1978 23(4), 618-625
LA: English
ER: M (Marine)
AB: Northeast Pacific water was collected by five different methods and the Cd in it was preconcentrated by both chelex-ion exchange and chelation-organic extraction techniques. All sampling and preconcentration methods yielded essentially the same data. Cadmium was very significantly correlated with phosphate and nitrate at all depths and it appears that the resulting equations, ng Cd-.-liter-SUP--1- = -3-.-6 + 34-.-9 (-mu-mol PO-SUB-4--.-liter-SUP--1-) and ng Cd-.-liter-SUP--1- = 5-.-1 + 2-.-45 (-mu-mol NO-SUB-3--.-liter-SUP--1-), can be used to predict oceanic Cd values. Cadmium concentrations are lowest in nutrient-depleted surface waters (4-.-5 0-.-4 ng-.-liter-SUP--1-) and greatest (125 ng Cd-.- liter-SUP--1-) at the depths of the PO-SUB-4- and NO-SUB-3- maxima. Hence, Cd has one of the highest deep enrichment:surface depletion ratios (equal to approximately 30) yet observed. Cadmium and phosphorus are also correlated in microplankton, and it is apparent that these organisms and their organic remains are a dominant factor in the biogeochemical cycling of this element.
AN: 8171410
359 of 369
TI: On the barium data from the Atlantic GEOSECS Expedition.
AU: Chan,-L.H.; Drummond,-D.; Edmond,-J.M.; Grant,-B.-(Dep.-Geol.,-Louisiana-State-Univ.,-Baton-Rouge,-LA-70803,-USA)
SO: Deep-Sea-Res., 1977 24(7), 613-649
LA: English
ER: M (Marine)
AB: Barium profiles at the Atlantic stations of the Geochemical Ocean Sections (GEOSECS) Program are remarkably similar to those for silicate and alkalinity. In nutrient depleted surface waters barium ranges between 36 and 44 nm kg-SUP--1-: the Arctic overflows have values between 44 and 49 nm kg-SUP--1- and the Antarctic Bottom Water 100 to 106 nm kg-SUP--1-. Both barium and silica behave non-conservatively in basins with restricted circulation - the Greenland and Norwegian seas and the Angola Basin - with anomalies of up to 1, 2 and 7 nm Ba kg-SUP--1-, respectively. There is extensive in situ production of silica and barium in the bottom waters of the Weddell Sea Basin, the silica anomaly ranging up to 35 -mu-m kg-SUP--1- and that for barium to 15 nm kg-SUP--1-. Barium behaves uniquely only in the upper waters. At tropical and temperate latitudes there is commonly a minimum of several nannomoles per kilogram in the uppermost thermocline, often associated with the high salinity core of the Sub-Tropical Underwater. In the Circumpolar Current the depletion in surface silica is associated with only a minor reduction in barium. The values at <5 -mu-m Si kg-SUP--1- are about 30 nm kg-SUP--1- higher than those at lower latitudes. The important question of the removal mechanism is not resolved from the profile data.
AN: 8006960
360 of 369
TI: An assessment of the environment impact of mining of the continental shelf.
AU: Owen,-R.M.-(Dep.-Atomos.-and-Ocean.-Sci.,-Univ.-Michigan,-Ann-Arbor,-MI-48104,-USA)
SO: Mar.-Min., 1977 1(1-2), 85-102
LA: English
ER: M (Marine)
AB: The ocean is a complex system and oceanographers have a limited understanding of the potential impact of mining on the marine environment. However, this lack of knowledge probably will not deter developed nations from commencing marine mining in the near future, because these nations are hard pressed to obtan critical minerals. This study is focused on an assessment of possible environmental disturbances associated with mining on the continental shelf, because a variety of political, economic, and technological factors suggest that the initial large-scale marine mining efforts will occur here. Mining activites on the continental shelf can disrupt the sediment budget and interfere with sediment dispersal patterns, resulting in coastal erosion and the formation of navigation hazards. The biogeochemical processes involved in photosynthesis and primary productivity, secondary productivity, and detoxification are also susceptible to environmental impacts caused by mining. The consequences of altering these processes may include the destruction of organisms and habitats, oxygen depletion, and the release of toxic substances from the sediments. Pre-mining baseline data and continuous monitoring of certain critical parameters at each mining site will be necessary to minimize adverse effects. Certain shelf environments will require special attention. These include fishing grounds, semi-enclosed embayments, and coral reefs.
AN: 8146840
361 of 369
TI: Production of methane and carbon dioxide from methane thiol and dimethyl sulphide by anaerobic lake sediments.
AU: Zinder,-S.H.; Brock,-T.D.-(Dep.-Earth-and-Space-Sci.,-UCLA,-Los-Angeles,-CA-90024,-USA)
SO: Nature, 1978 273(5659), 226-228
LA: English
ER: F (Freshwater)
AB: Methane thiol (methyl mercaptan, MeSH), its oxidation product, dimethyl disulphide (DMDS), and dimethyl sulphide (DMS) are naturally occurring metabolites. They are also produced by paper mills using the kraft pulp process and cause an industrial odour problem because of their low odour threshold. Although the biological production of these compounds is fairly well understood, little is known about their biological decomposition. The authors report that microbial populations present in anaerobic freshwater sediments and in anaerobic sewage digestor sludge are capable of metabolising the carbon in these volatile organic sulphur compound to methane and carbon dioxide. Therefore, anaerobic habitats may serve as sinks in the biogeochemical cycling of these compounds.
AN: 8109850
362 of 369
TI: Applications of polarography and voltammetry to marine and aquatic chemistry: 4. A new voltammetric method for the study of mercury traces in sea water and inland waters.
AU: Sipos,-L.; Valenta,-P.; Nurnberg,-H.W.; Branica,-M.-(Cent.-Mar.-Res.,-Inst.-'-Rudjer-Boskovic'-,-Zagreb,-Croatia,-Yugoslavia)
SO: J.-Electroanal.-Chem.-and-Interfacial-Electrochem., 1977 (77), 263-266
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Mercury is well known as one of the most toxic metals in the environment. In sea water and inland waters mercury is dissolved usually at the ultra trace level (typically 0-.-1-0-.-01 -mu-gl-SUP--1-). Nevertheless the dissolved state is an important stage in the biogeochemical cycle of toxic metals as from there they interact with sediments and they also enter the marine and aquatic food chain due to accumulation by aquatic organisms. A reliable voltammetric approach to the determination of Hg is thus of particular importance for aquatic environmental trace chemistry. A series of preliminary tests convinced us that gold is the preferable electrode material and that the combination of several methodological principles of advanced polarography and voltammetry would provide an optimal performance with respect to accuracy and precision at the required high sensitivity level. The method developed consists of differential pulse anodic stripping in the subtractive mode (DPASV-S) at a twin disc gold electrode rotating with 1500 rpm during the cathodic deposition stage where a particular program of polarization is applied.
AN: 8135280
363 of 369
TI: Biogeochemical studies in the sea: studies on primary production and its relationship to the metabolism of organic matter in the marine and lacustrine environment.
AU: Saijo,-Y.-(Water-Res.-Inst.,-Nagoya-Univ.,-Chikusa,-Nagoya-464,-Japan)
SO: J.-Oceanogr.-Soc.-Jap., 1977 33(5), 290-296
LA: Japanese
AB: The studies on metabolism of organic matter in aquatic environments first involved research on the sedimentation process of organic matter in lacustrine environments. Subsequent measures of primary production in lake and sea water were undertaken to know the organic substance supply into the metabolism. After establishing the routine technique of productivity measurement in aquatic environment, the primary production and the photosynthetic characteristics in waters in the northwestern Pacific, the western Indian Ocean and the Antarctic Sea were studied. Following the development of new methods to determine the organic substances in the dissolved and particulate forms and chlorophyll pigment in seawater, their distributions in both horizontal and vertical directions were determined. The author has also been interested in the mechanism producing a subsurface chlorophyll maximum in the ocean. In addition, interest has been directed to the coastal waters. The nitrogen cycle was studied in oyster beds and the research on eutrophication processes in a shallow bay is being carried out from the aspect of production and decomposition of organic matter.
AN: 8125000
364 of 369
TI: High molecular weight organic matter in seawater. [Presented at: NATO/ONR Symposium on 'Concepts in Marine Organic Chemistry'; Edinburgh (UK); 6 Sep 1977].
AU: Ogura,-N.-(Dep.-Environ.-Sci.-Conserv.,-Tokyo-Univ.-Agric.-and-Technol.,-Fuchu,-Tokyo-183,-Japan)
CO: [Presented at: NATO/ONR Symposium on 'Concepts in Marine Organic Chemistry' Edinburgh (UK) 6 Sep 1977].
SO: Mar.-Chem., 1977 5(4-6), 535-549
LA: English
ER: M (Marine)
AB: The presence and nature of high molecular weight organic matter in seawater was critically reviewed and its biogeochemical cycle was discussed. Organic matter that passes through a filter of 0-.-5-1 -mu-m pore size is called dissolved and that which does not pass through such a filter is defined as particulate. The size of colloidal particles ranges from 0-.-001 to 1 -mu-m, and therefore, they are included in the dissolved fraction having high molecular weight. High molecular weight organic matter greater than 100 000 molecular weight was found in the seawater of Tokyo Bay. The values ranged from 0-.-1 to 1-.-5 mgC/l, and accounted for 8-45% of the total dissolved organic matter. Decomposition experiments on dissolved organic matter showed that macromolecular organic matter is refractory to bacterial attack. However, macromolecular organic materials tend to aggregate or adsorb on small particles to a sufficient size for precipitation. Organic aggregates thus formed sink to the bottom of the sea and bioelements included in them are removed from water column. High molecular weight organic materials are, therefore, considered to play an important role in transportation and distribution of matter in seawater. In order to elucidate the chemical and biological properties of macromolecular organic matter, concentration and isolation of this material are important, using methods such as adsorption on organic adsorbents or ultrafiltration.
AN: 8089380
365 of 369
TI: Biokinetics of neptunium-237 in mussels and shrimp.
AU: Guary,-J.C.; Fowler,-S.W.-(Internatl.-Lab.-Mar.-Radioactivity,-IAEA,-Mus.-Oceanogr.,-Monaco)
SO: Mar.-Sci.-Commun., 1977 3(3), 211-229
LA: English
ER: M (Marine)
AB: Neptunium-237 kinetics were studied in marine shrimp and mussels using a thick source alpha counting technique. Bioaccumulation of -SUP-237-Np from water was relatively slow in both species, reaching whole body concentration factors of only 15 to 20 after three months. Surface adsorption was implicated in the initial uptake. Both uptake and loss of the radioisotope were not significantly affected by temperature; this may be a reflection of the physical nature of the uptake. By virtue of the large amounts of accumulated -SUP-237-Np associated with the exoskeleton of shrimp, molting will play an important role in the biogeochemical cycling of this transuranic in the marine environment. Rapid growth of organisms like mussels acts to reduce the -SUP-237-Np concentration in tissues during a period of decontamination.
AN: 8025060
366 of 369
TI: The chemical composition of Central Amazonian aquatic macrophytes with special reference to their role in the ecosystem.
AU: Howard-Williams,-C.; Junk,-W.J.-(Inst.-Freshwater-Stud.,-Rhodes-Univ.,-Grahamstown,-South-Africa)
SO: Arch.-Hydrobiol., 1977 79(4), 446-464
LA: English
ER: F (Freshwater)
AB: Levels of ash, Na, K, Ca, Mg, Si, N, P, dry matter, polyphenols, potential energy (calories) and cell wall material were determined from 23 species of aquatic plants from the Central Amazon. Levels of P and K were particularly high in the aquatic plants when compared with the amounts of these elements in the soils and waters of the area, although Ca was extremly low in the macrophytes. The role of the macrophytes as nutrient reservoirs and in the biogeochemical cycle of the varzea lakes of the Central Amazon is discussed.
AN: 8056320
367 of 369
TI: Biokinetics of neptunium-237 in mussels and shrimp
AU: Guary,-J.C.; Fowler,-S.W.-(Internatl.-Lab.-Mar.-Radioactivity-IAEA,-Mus.-Oceanogr.,-Monaco)
SO: Mar.-Sci.-Commun., 1977 3(3), 211-229
LA: English
ER: M (Marine)
AB: Neptunium-237 kinetics were studied in marine shrimp and mussels using a thick source alpha counting technique. Bioaccumulation of -SUP-237-Np from water was relatively slow in both species, reaching whole body concentration factors of only 15 to 20 after three months. Surface adsorption was implicated in the initial uptake. Both uptake and loss of the radioisotope were not significantly affected by temperature; this may be a reflection of the physical nature of the uptake. By virtue of the large amounts of accumulated -SUP-237-Np associated with the exoskeleton of shrimp, molting will play an important role in the biogeochemical cycling of this transuranic in the marine environment. Rapid growth of organisms like mussels acts to reduce the -SUP-237-Np concentration in tissues during a period of decontamination.
AN: 8025060
368 of 369
TI: Processes of organic production on coral reefs
AU: Lewis,-J.B.-(Redpath-Mus.-Mar.-Sci.-Cent.,-McGill-Univ.,-Montreal,-Quebec,-Canada)
SO: Biol.-Rev.-Camb.-Philos.-Soc., 1977 52(3), 305-347
LA: English
ER: M (Marine)
AB: Rates of gross primary production on reefs vary between 300-5000 gC/m-SUP-2-/yr. These rates are higher than general oceanic values and as high as those of the most productive marine communities. Sources of primary production include fleshy macrophytes, calcareous algae, filamentous algae on the coral skeletons or calcareous rock, marine grasses and the zooxanthellae within coral tissue. Production values from the various sources fall within the range of production of reefs as a whole. There is evidence to suggest that nitrogen and phosphorus are recycled rapidly on the reef and that nitrogen is fixed by bacteria and primary producers. The weight of evidence suggests that while there is a removal of zooplankton by benthic organisms, the total biomass carried over the reef is too small to support the energy needs of secondary production. Bacteria are a potential source of energy for secondary production on reefs and are implicated in nitrogen fixation, decomposition and biogeochemical cycling. Estimates of reef growth have been made from measurements of coral growth and from the flux of calcium carbonate. Hydrographic factors influence growth and form of reefs and their is some evidence to show that production is enhanced by conservation of water in lagoonal areas.
AN: 8029540
369 of 369
TI: The chemical composition of central Amazonian aquatic macrophytes with special reference to their role in the ecosystem
AU: Howard-Williams,-C.; Junk,-W.J.-(Max-Planck-Inst.-Limnol.,-Ploen,-GFR)
SO: Arch.-Hydrobiol., 1977 79(4), 446-464
NT: 47 ref
LA: English
ER: F (Freshwater)
AB: Levels of ash, Na, K, Ca, Mg, Si, N, P, dry matter, polyphenols, potential energy (calories) and cell wall material were determined from 23 species of aquatic plants from the Central Amazon. Levels of P and K were particularly high in the aquatic plants when compared with the amounts of these elements in the soils andn waters of the area, although Ca was extremely low in the macrophytes. The role of the macrophytes as nutrient reservoirs and in the biogeochemical cycle of the varzea lakes of the Central Amazon is discussed.
AN: 7010080
No. Records Request
1: 504 BIOGEOCHEMICAL
2: >8530 CYCL*
3: 369 BIOGEOCHEMICAL CYCL*
Searches and records above from: ASFA 1978-1987
5: 1521 #3
1 of 1521
TI: Biogeochemical transformations of nitrogen and phosphorus in the marine environment -- coupling hydrodynamic and biogeochemical processes in models for the Baltic proper
AU: Savchuk,-O.; Wulff,-F.
AF: State Oceanographic Inst., St Petersburg Branch, 23d Line, 2A, 199026, St Petersburg, Russia
SO: SYST.-ECOL.-CONTRIB. 1996 no. 2, 79 pp
LA: English
ER: M (Marine)
AB: Numerical models explicitly simulating complex interactions between physical and biogeochemical processes are an important tool to study these phenomena at the ecosystem level. This technical report describes the continued development of a coupled hydrodynamic-biogeochemical model, originally presented by Stigebrandt & Wulff. The further developments of this model have followed the strategy adopted for a research program on the large-scale effects of pollution of the Baltic Sea, funded by the Swedish Environmental Protection Agency. For model development, a cooperation was initiated with the Russian 'Project Baltica' where similar models have been developed. A sub-model that couples the nitrogen and phosphorus pelagic cycles in the upper layers of the water column was described in Savchuk & Wulff. Here we present some results from the development of the biochemical sub-models with descriptions of nitrogen fixation and of sediment-water interactions which has been coupled with the hydrodynamic sub-model and implemented for the Baltic Proper. We have also verified the model results in an extensive analysis of observations from the Baltic and other marine areas.
AN: 3971280
2 of 1521
TI: Phosphorus metabolism in anthropogenically transformed lagoon ecosystems: The Comacchio lagoons (Ferrara, Italy)
AU: Sorokin,-Y.I.; Dallocchio,-F.; Gelli,-F.; Pregnolato,-L.
AF: Dipto. di Biochimica e Biol. Molecolare, via Borsari 46, 44100 Ferrara, Italy
SO: J.-SEA-RES. 1996 vol. 35, no. 4, pp. 243-250
LA: English
ER: B (Brackish)
AB: Inorganic phosphorus dynamics were investigated with the use of super(32)P in the hypertrophic Comacchio lagoons (NE Adriatic) during an extremely dense, quasi-permanent bloom of picocyanobacteria. Concentrations of dissolved inorganic phosphate (DIP) in waters of the blooming lagoons were usually near the detection limit (0.01 mu moles/dm super(3)). DIP uptake rates by microplankton at near-ambient concentrations (0.01 to 0.1 mu moles/dm super(3)) were in the range of 9.6 to 16.1 nmoles P/dm super(3)/min, and turnover times were 1.5 to 3 min. The turnover time was >40 h in the eutrophic coastal waters of the adjacent Adriatic Sea. The uptake rate of DIP depended on its initial concentration. In water samples artificially enriched with DIP, the uptake rate rose to its maximum of 0.10 to 0.13 mu moles P/dm super(3)/min (or similar to 6 to 7 mu moles/dm super(3)/h) when the initial concentration of DIP was elevated to 10 to 20 mu moles/dm super(3). The potential capacity of microplankton in the water samples to consume and retain DIP was estimated at similar to 25 mu moles/dm super(3). Specific features are discussed of phosphorus metabolism in the anthropogenically transformed lagoon ecosystem with an anomalous food web with few animals.
AN: 3970980
3 of 1521
TI: Some aspects of iron cycling in maritime Antarctic lakes
AU: Ellis-Evans,-J.C.; Lemon,-E.C.G.
AF: Bri. Antarc. Surv., Nat. Environ. Res. Counc., High Cross, Madingley Rd., Cambridge, CB3 OET, UK
CO: 23. Cong. of the Societas Internationalis Limnolgiae Hamilton (New Zealand) [nd]
SO: HIGH-LATITUDE-LIMNOLOGY. Vincent,-W.F.;Ellis-Evans,-J.C.-eds. 1989 vol. 172 pp. 149-164
ST: HYDROBIOLOGIA vol. 172
LA: English
ER: F (Freshwater)
AB: Iron occurs in extremely high concentrations in certain maritime Antarctic freshwater lakes which seasonally develop an anoxic zone. In oligotrophic Sombre Lake the data show that Fe(II) precipitates as Fe(III) oxyhydroxides which bind phosphorus and return it to the sediments. In nutrient-enriched Amos Lake, significant quantities of sulphide are also produced and this binds a proportion of the released Fe(II) so reducing the ratio of total iron to phosphorus at the redox boundary where the oxyhydroxides are formed. A proportion of the sediment-released phosphorus therefore reaches the upper waters of this lake (unlike in Sombre Lake) and provides the initial nutrient source for under-ice phytoplankton development in spring. Iron-reducing bacteria have been isolated, from Sombre Lake sediments, which apparently utilise the abundant Fe(III) oxyhydroxides. From thermodynamic considerations (assuming Fe(III) is not limiting) these should outcompete sulphate reducers and methanogens (both previously reported from Sombre and Amos Lakes) and could therefore constitute an important component of the anaerobic mineralisation of organic carbon in such lakes (DBO).
AN: 3969753
4 of 1521
TI: A 420,000-year record of cyclicity in oceanic and atmospheric processes from the eastern Equatorial Pacific
AU: Rea,-D.K.; Chambers,-L.W.; Chuey,-J.M.; Janecek,-T.R.; Leinen,-M.; Pisias,-N.G.
AF: Oceanogr. Program, Dep. Atmos. and Ocean. Sci., Univ. Michigan, Ann Arbor, MI, USA
SO: PALEOCEANOGRAPHY 1986 vol. 1, no. 4, pp. 577-586
NT: Special issue: Milankovitch cycles through geologic time.
LA: English
ER: M (Marine)
AB: (DBO).
AN: 3969648
5 of 1521
TI: Cyclic patterns in the Paleozoic and Mesozoic: Implications for time scale calibrations
AU: Bayer,-U.; McGhee,-G.R.,Jr.
AF: Dep. Geol. Sci., Wright Geol. Lab., Rutgers Univ., New Brunswick, NJ, USA
SO: PALEOCEANOGRAPHY 1986 vol. 1, no. 4, pp. 383-402
NT: Special issue: Milankovitch cycles through geologic time.
LA: English
ER: M (Marine)
AB: (DBO).
AN: 3969634
6 of 1521
TI: Cyclicity in the Milankovitch band through geologic time: An introduction
AU: Arthur,-M.A.; Garrison,-R.E.
AF: Grad. Sch. Oceanog., Univ. Rhode Island, Narragansett, RI, USA
SO: PALEOCEANOGRAPHY 1986 vol. 1, no. 4, pp. 369-372
NT: Special issue: M: lankovitch cycles through geologic time.
LA: English
ER: M (Marine)
AB: (DBO).
AN: 3969632
7 of 1521
TI: Tectonic cycles and the history of the earth's biogeochemical and paleoceanographic record
AU: Worsley,-T.R.; Nance,-R.D.; Moody,-J.B.
AF: Dep. Geol. Sci. Ohio Univ., Athens, OH, USA
SO: PALEOCEANOGRAPHY 1986 vol. 1, no. 3, pp. 233-263
LA: English
ER: M (Marine)
AB: (DBO).
AN: 3969624
8 of 1521
TI: The effect of phosphate status on the kinetics of cyanophage infection in the oceanic cyanobacterium Synechococcus sp. WH7803
AU: Wilson,-W.H.; Carr,-N.G.; Mann,-N.H.
AF: Dep. Biol. Sci., Univ. Warwick, Coventry CV4 7AL, UK
SO: J.-PHYCOL. 1996 vol. 32, no. 4, pp. 506-516
LA: English
ER: M (Marine)
AB: Phycoerythrin-containing Synechococcus species are considered to be major primarily producers in nutrient-limited gyres of subtropical and tropical oceanic provinces, and the cyanophages that infect them are thought to influence marine biogeochemical cycles. This study begins an examination of the effects of nutrient limitation on the dynamics of cyanophage/Synechococcus interactions in oligotrophic environments by analyzing the infection kinetics of cyanophage strain S-PM2 (Cyanomyoviridae isolated from coastal water off Plymouth, UK) propagated on Synechococcus sp. WH7803 grown in either phosphate-deplete or phosphate-replete conditions. When the growth of Synechococcus sp. WH7803 in phosphate-deplete medium was followed after infection with cyanophage, an 18-h delay in cell lysis was observed when compared to a phosphate-replete control. Synechococcus sp. WH7803 cultures grown at two different rates (in the same nutritional conditions) both lysed 24 h postinfection, ruling out growth rate itself as a factor in the delay of cell lysis. One-step growth kinetics of S-PM2 propagated on host Synechococcus sp. WH7803, grown in phosphate-deplete and-replete media, revealed an apparent 80% decrease in burst size in phosphate-deplete growth conditions, but phage adsorption kinetics of S-PM2 under these conditions showed no differences. These results suggested that the cyanophages established lysogeny in response to phosphate-deplete growth of host cells. This suggestion was supported by comparison of the proportion of infected cells that lysed under phosphate-replete and-deplete conditions, which revealed that only 9.3% of phosphate-deplete infected cells lysed in contrast to 100% of infected phosphate-replete cells. Further studies with two independent cyanophage strains also revealed that only approximately 10% of infected phosphate-deplete host cells released progeny cyanophages. These data strongly support the concept that the phosphate status of the Synechococcus cell will have a profound effect on the eventual outcome of phage-host interactions and will therefore exert a similarly extensive effect on the dynamics of carbon flow in the marine environment.
AN: 3969472
9 of 1521
TI: Interannual variability of a salt-marsh ecosystem
AU: Teal,-J.M.; Howes,-B.L.
AF: Woods Hole Oceanographic Inst., Woods Hole, MA 02543, USA
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 4, pp. 802-809
LA: English
ER: B (Brackish)
AB: Data from Great Sippewissett Salt Marsh are used to gauge the extent of change of Spartina alterniflora marsh during periods of several to 22 yr. Our data all relate to plant production: from aboveground, maximum plant biomass measured over the entire period; from belowground, live root and rhizome biomass measured in 1974 and 1983, CO sub(2) evolution from the sediments for 7 yr, and pore-water concentrations of dissolved sulfide for 6 yr. All the measures indicated a relatively low degree of interannual change in salt-marsh areas vegetated by tall- and short-form S. alterniflora. The similarity in both plant and biogeochemical parameters between years is likely related to the regular, high-frequency tidal flooding of grass stands. These interannual comparisons of each quantified parameter support the contention that measurements made in any single year can be applied to other years with suitable precautions to account for seasonal cycles. Our data also illustrate the importance of long time series for establishing sound correlations in environmental data.
AN: 3968891
10 of 1521
TI: Biogeochemistry of N, P and Si in Baltic Sea sediments: Response to a simulated deposition of a spring diatom bloom
AU: Conley,-D.J.; Johnstone,-R.W.
AF: National Environmental Research Institute, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark
SO: MAR.-ECOL.-PROG.-SER. 1995 vol. 122, no. 1-3, pp. 265-276
NT: Bibliogr.: 68 ref.
LA: English
ER: M (Marine)
AB: Experimental studies of intact cores from the Baltic Sea were conducted to determine the response of sediment nutrient recycling processes to varied inputs of organic matter. A 2 mo enrichment experiment was carried out in the laboratory on sediment cores held at 4 degree C using a flow-through system where overlying waters were continuously replaced at a rate of 1 d super(1) The experiments were designed to simulate the deposition of organic matter that occurs during a typical spring diatom bloom (1x) and under enriched conditions with eutrophication at approximately 3 times (3x) a normal spring bloom utilizing added organic matter from a natural phytoplankton assemblage collected in a eutrophic coastal fjord during the spring diatom bloom. Low and constant sediment-water fluxes were observed throughout the duration of the experiment in control cores with no added organic matter. In all cases an immediate response was noted when a single pulsed addition of algal material was added to the sediment surface. Sediment-water fluxes of ammonium (NH sub(4) super(+)), and dissolved inorganic phosphate (DIP) increased significantly (ANOVA, p <0.01). For nitrite + nitrate (NO sub(2) super(-) + NO sub(3) super(-)) and dissolved silicate (DSi) sediment-water fluxes, differences were initially observed; however, only the NO sub(2) super(-) + NO sub(3) super(-) fluxes were significantly different over time (ANOVA, p <0.01). Fluxes of NO sub(2) super(-) + NO sub(3) super(-) were into the sediment for 3 to 10 d after addition of organic material, followed by small fluxes out of the sediment. The addition of algal material proportionate to a normal spring bloom (1x) had only a minor effect on porewater nutrient concentrations, whereas the 3x treatment substantially modified both the short- and long-term response of sediments. A greater proportion of anaerobic decomposition products, e.g. NH sub(4) super(+) and DIP, were observed with an expansion of more reducing conditions resulting from the addition of organic matter. The percentage of Si remineralized decreased as the flux of material to the sediment increased. Deposition rates similar to a typical spring bloom did not have long-term effects on the nutrient recycling processes; however, increases in the present level of deposition (as simulated in this study), which are forecasted with further eutrophication in the Baltic Sea, may have a significant impact on nutrient biogeochemical cycles.
AN: 3967434
11 of 1521
TI: Modelling areal hypolimnetic oxygen demand in lakes
AU: Chapra,-S.C.; Bachmann,-R.W.; Jones,-J.R.; Peters,-R.H.; Soballe,-D.M.-(eds.)
AF: Univ. Colorado, Boulder, CO 80309-0428, USA
CO: 15. Annual International Symposium of the North American Lake Management Society, Toronto, ON (Canada), 6-11 Nov 1995
SO: LAKE-RESERV.-MANAGE. 1995 vol. 11, no. 2, p. 125
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: After a brief review of empirical AHOD models, a new mechanistic approach is described. The approach employs a mass balance for the hypolimnion that can be solved for temporal changes in oxygen concentration as a function of time. Thermocline fluxes include settling of particulate organic carbon (POC) and diffusion of both POC and oxygen. Hypolimnetic oxygen sinks include carbon decomposition and nitrification in the water and sediment oxygen demand (SOI). The latter is linked to settling POC using Di Toro's estuary SOD modelling framework. This framework is modified to apply to freshwater systems. In particular, methanogenesis and methane bubble formation are included. The approach is demonstrated by applying it to Cascade Reservoir in Idaho. Finally, a comparison between the mechanistic model and empirical approaches is presented.
AN: 3966922
12 of 1521
TI: Seasonal and interannual variability in primary production and particle flux at Station ALOHA
AU: Karl,-D.M.; Christian,-J.R.; Dore,-J.E.; Hebel,-D.V.; Letelier,-R.M.; Tupas,-L.M.; Winn,-C.D.
AF: Dep. Oceanogr., Sch. Ocean and Earth Sci. and Technol., Univ. Hawaii, 1000 Pope Rd., Honolulu, HI 96822, USA
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1996 vol. 43, no. 2-3, pp. 539-568
NT: Special issue: Ocean time-series: Results from the Hawaii and Bermuda research programs.
LA: English
ER: M (Marine)
AB: A 5-year time-series study of primary production and euphotic-zone particle export in the subtropical North Pacific Ocean near Hawaii (Sta. ALOHA, 22 degree 45'N, 158 degree W) with measurements collected at approximately monthly intervals has revealed significant variability in both ecosystem processes. Depth-integrated (0-200 m) primary production averaged 463 mg C m super(-2) day super(-1) (s = 156, n = 54) or 14.1 mol C m super(-2) year super(-1). This mean value is greater than estimates for the North Pacific Ocean gyre made prior to 1984, but conforms to data obtained since the advent of trace metal-clean techniques. Daily rates of primary productivity at Sta. ALOHA exhibited interannual variability including a nearly 3-year sustained increase during the period 1990-1992 that coincided with a prolonged El Nino-Southern Oscillation (ENSO) event. Export production, defined as the particulate carbon (PC) flux measured at the 150 m reference depth, also varied considerably during the initial 5 years of the ongoing field experiment. The PC flux averaged 29 mg C m super(-2) day super(-1) (s = 11, n = 43) or 0.88 mol C m super(-2) year super(-1). A 5-fold variation between the minimum and maximum fluxes, measured in any given year, was observed. During the first 3 years of this program (1989-1991), a pattern was resolved that included two major export events per annum one centered in late winter and the other in late summer. After 1991, export production exhibited a systematic decrease with time during the prolonged ENSO event. When expressed as a percentage of the contemporaneous primary production, PC export ranged from 2 to 16.9%, with a 5-year mean of 6.7% (s = 3.3, n = 40). Contrary to existing empirical models, contemporaneous primary production and PC flux were poorly correlated, and during the ENSO period they exhibited a significant inverse correlation. This unexpected decoupling of particle production and flux has numerous implications for oceanic biogeochemical cycles and for the response of the ocean to environmental perturbations.
AN: 3965261
13 of 1521
TI: Cost-effective lake analysis: 20-20 Hind sight
AU: Welch,-E.B.; Jacoby,-J.M.; Bachmann,-R.W.; Jones,-J.R.; Peters,-R.H.; Soballe,-D.M.-(eds.)
AF: Dep. Civ. Eng., Univ. Washington, Seattle, WA 98195, USA
CO: 15. Annual International Symposium of the North American Lake Management Society, Toronto, ON (Canada), 6-11 Nov 1995
SO: LAKE-RESERV.-MANAGE. 1995 vol. 11, no. 2, pp. 201-202
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Water and nutrient budgets and trophic assessment are recommended and often required in Phase I diagnostic prerestoration studies (Cooke et al., 1993; USEPA, 1990). Annual water and nutrient budgets are costly, may be inaccurate and are often of minor importance in assessing the cause(s) for summer algal and macrophyte problems. If internal phosphorus (P) loading is suspected as the major cause for summer algal problems, a more cost-effective approach is to directly determine internal P loading from lake data and calculate external nonpoint loading with a mass balance model (Cooke et al., 1993) during summer when algal problems are usually most prevalent. Surface inflows are usually low, but internal loading is highest during that period. If macrophytes are the main problem, water and nutrient budgets are of minor importance in subsequent management schemes. Costly nitrogen analyses would probably be eliminated, because reduction in N would rarely be recommended to control algae. In 11 of 14 cases in Washington State, corrective action could have been recommended without expensive, time consuming water and nutrient budgets. For future protection of lakes of low trophic state or if knowledge of the relative contribution of P from subwatersheds is important, then complete water and P budgets would be necessary. However, the prevailing approach to start with complete water and P budgets for all lakes, or that inlake treatments should occur only after external loads are controlled may not be cost-effective, especially if external loads are nonpoint and of minor importance during summer when algal problems usually occur.
AN: 3964127
14 of 1521
TI: Bacterial populations and processes in sediments containing gas hydrates (ODP Leg 146: Cascadia Margin)
AU: Cragg,-B.A.; Parkes,-R.J.; Fry,-J.C.; Weightman,-A.J.; Rochelle,-P.A.; Maxwell,-J.R.
AF: Dep. Geol., Univ. Bristol, Bristol BS8 1RJ, UK
SO: EARTH-PLANET.-SCI.-LETT. 1996 vol. 139, no. 3-4, pp. 497-507
LA: English
ER: M (Marine)
AB: Bacterial populations and activity were quantified at three sites in the Cascadia Margin accretionary wedge, off the West Canadian/American coast (ODP Leg 146). At two sites sediments contained gas hydrates, Site 889/890 had a discrete zone of hydrate approximately 10 m above a bottom simulating reflector (BSR) at 225 m below sea floor (mbsf) and Site 892 had disseminated hydrate in the upper 20 mbsf and a BSR at 74 mbsf. Site 888 was a control site without gas hydrates. The control site (888) and top approximately 90 mbsf of Site 889/890 had bacterial distributions similar to previous Pacific Ocean sites. In the upper approximately 30 m of Site 892, however, bacterial populations were much lower, suggesting inhibition by the high concentrations of H sub(2)S within the hydrate zone. Below this depth bacterial populations rose to concentrations consistent with other sites. The control site was dominated by SO sub(4) reduction and rates of CH sub(4) oxidation in the top 90 m were low (0.002-0.033 nmol cm super(-3) d super(-1)). At Site 889/890 bacterial populations and activity were stimulated in the discrete hydrate zone. CH sub(4) oxidation rates increased in the middle of this zone to 134.5 nmol cm super(-3) d super(-1) (ca. 9 times the average rate at other depths), resulting in a significant (x 10) increase in the total bacterial population. The anaerobic process(es) responsible for this oxidation remain unclear, despite SO sub(4)-reducing bacteria, previously associated with CH sub(4) oxidation, also being stimulated in this zone. Fluid flux into accretionary wedge sediments may be an important process in providing electron acceptors to maintain these relatively high rates of CH sub(4) oxidation. This first microbiological study of gas hydrates indicates that bacterial processes are influenced by gas and fluid venting, and they play a major role in geochemical changes within these deep (> 200 mbsf) sediments.
AN: 3964064
15 of 1521
TI: Production of methanethiol from dimethylsulfoniopropionate in marine surface waters
AU: Kiene,-R.P.
AF: Department of Marine Sciences, University of South Alabama, LSCB 25, Mobile, AL 36688-0002, USA
SO: MAR.-CHEM. 1996 vol. 54, no. 1, pp. 69-83
LA: English
AB: Degradation of nM levels of dissolved dimethylsulfoniopropionate [DMSP(d)] in surface water samples from the Gulf of Mexico and Gulf of Maine was accompanied by the accumulation of both dimethylsulfide (DMS) and methanethiol (MeSH). The mean net yields for DMS and MeSH, in terms of sulfur from DMSP, were 32% (range 12-66%) and 22 % (range 3-64%), respectively. In six out of seventeen experiments, maximum net accumulations of MeSH were equivalent to, or greater than, those obtained for DMS. No relationship between net DMS and MeSH accumulations was found when all mseventeen experiments were considered. Inhibition of DMSP(d) degradation with 50 mu M glycine betaine substantially lowered production of both MeSH and DMS, indicating that degradation of DMSP was required to produce these sulfur gases. The most likely route for MeSH formation is from demethiolation of 3-methiolpropionate (MMPA), a product of DMSP demethylation. Experimental additions of MMPA confirmed that MeSH could be produced from this compound. The MeSH produced from DMSP was rapidly lost in all water samples tested, much more rapidly than DMS. Direct determinations of MeSH loss rate constants showed these to fall in the range of 0.14-1.4 h-1 in different water samples. Filtration of water through 0.2- mu m membrane filters resulted in a 1.3-4.5-fold decrease in the whole water loss rate constants, suggesting biological or particle sinks for MeSH. Addition of Suwannee River humic acid accelerated the loss of MeSH from filtered water, suggesting a possible interaction between MeSH and DOM. The results of this study indicate that a substantial fraction of the DMSP(d) degraded in aerobic seawater is converted to MeSH. The diversion of DMSP-sulfur to MeSH represents an important biogeochemical control on the production of climatically active DMS. In addition, the production of highly reactive MeSH suggests that the degradation of DMSP may have a more important impact on the chemistry of marine surface waters than previously recognized.
AN: 3961419
16 of 1521
TI: The biogenic silica production in the ocean: From the Weddel Sea to the Antarctic Ocean
OT: La production de silice biogenique dans l'ocean: de la mer de Weddel a l'ocean antarctique
AU: Leynaert,-A.
CA: Paris 6 Univ., (France)
SO: PARIS-FRANCE UNIV.-PARIS-6 1993 93 pp
LA: French
ER: M (Marine)
AB: The aim of the study was to establish the level of the biogenic silica production in the surface waters of the Antarctic Ocean, to assess the question of the silica paradox: how can a region of the world ocean account for less than 5% of the world's primary production, when it is the site of the 2/3 of the global accumulation of modern biogenic siliceous sediment? Within a framework of international co-operation we developed and improved a new method of determination of biogenic silica production. This method is based upon the use of radioactive isotope of silicon, whose radioactive daughter can be readily radioassay in waters by means of its Cerenkov radiations. This new technique presents several advantages: it can be use in oligotrophic areas, it doesn't require any samples preparation and preliminary silicic uptake rates can be determined aboard ship. In the meanwhile, we measured stocks and fluxes of biogenic silica in two regions of the Antarctic Ocean: the Weddel Sea and the Ross Sea. The results, along with previously collected data, are the support for a new estimate of the biogenic silica annual production in the Antarctic ocean. Limited to the area south of the Polar front, this estimate ranges between eleven and thirty two tera-moles of silicium per year, significantly lower than previously published values. When referring to the global marine silica production of the World ocean, the Antarctic contribution would account for no more than 4 to 21%.
AN: 3960989
17 of 1521
TI: Use of fluorogenic model substrates for extracellular bacterial enzyme activity (EEA)
OT: Utilisation d'un substrat modele fluorogene pour mesurer l'activite enzymatique extracellulaire (AEE) bacterienne
AU: Talbot,-V.; Bianchi,-M.
AF: Microbiologie marine CNRS UPR 223, Campus de Luminy, case 907, 13288 Marseille cedex 9, France
CA: Ecole thematique du CNRS, Banyuls-sur-Mer (France)
CO: Ecologie Bacterienne des Milieux Aquatiques, Banyuls-sur-Mer, 15-27 Oct 1995
SO: BACTERIAL-ECOLOGY-OF-THE-AQUATIC-ENVIRONMENTS.-ECOLOGIE-BACTERIENNE-DES-MILIEUX-AQUATIQUES. Lebaron,-P.-ed. PARIS-FRANCE INSTITUT-OCEANOGRAPHIQUE 1995 vol. 21, no. 1 pp. 247-260
ST: OCEANIS-DOC.-OCEANOGR. vol. 21, no. 1
LA: French
ER: M (Marine)
AB: Most of organic compounds produced in natural waters have a polymeric structure and have to be hydrolysed by extracellular enzymes before incorporation into the bacterial cell. Use of fluorogenic model substrates for extracellular enzyme activity (EEA) measurement of bacteria is a rapid and sensitive method. These substrates contain an artificial fluorescent molecule the methylumbelliferone (MUF) or the 4-methylcoumarinyl-7-amide (MCA) linked by a specific binding to a natural molecule (e.g. amino acids glucose). The fluorescence is observed after enzymatic splitting of the complex molecule and is measured by spectrofluorometry. Several model substrates are available and permit the measurement of the EEA of most of enzymes (e.g. aminopeptidase glucosidase phosphotase galactosidase sulfatase). Different concentrations have to be used to approach the in situ activity and maximum activity, or to determine the kinetic parameters (Vm and Km). Moreover ectoenzyme activity could provide an indication of the organic matter flux crossing through the microbial loop as well as the quantity and quality of the organic matter in the environment. Therefore EEA plays a key role in the organic matter flux and in the biogeochemical cycles.
AN: 3960888
18 of 1521
TI: Estimate of state variables of a trophic web model in the Bay of Brest
OT: Estimation des variables d'etat d'un modele de reseau trophique benthique en Rade de Brest
AU: Jean,-F.; Thouzeau,-G.
AF: URA 1513 CNRS, UFR Sciences et Techniques, 6 Av. Le gorgeu, BP 809, 29285 Brest Cedex, France
SO: C.-R.-ACAD.-SCI.-SER.-3-SCI.-VIE-LIFE-SCI. 1995 vol. 318, no. 1, pp. 145-154
LA: French
ER: M (Marine)
AB: Winter biomasses of the benthic fauna in the Brest Roadsted were estimated to model carbon fluxes through the benthic food web. Total biomass (9.59 g C m super(-2)) is dominated by macrofaunal suspension feeders (53%) and carnivores (25%). Macrofaunal deposit feeders and herbivores, meiofauna, bacteria and demersal fishes accounted for 22% of total biomass. Most of the biomass was found on coarse coralline algae bottoms in relation to environmental and biotic factors. Mean macrofaunal biomass is significantly higher in the Bay of Brest than in many other temperate coastal ecosystems. The proliferation of suspension feeders in the Bay would correspond to the first perturbation level of the ecosystem due to organic enrichment. Suspension feeders would prevent eutrophication 6y controlling phytoplankton biomass.
AN: 3960874
19 of 1521
TI: Modeling the diurnal cycle of carbon monoxide: Sensitivity to physics, chemistry, biology, and optics
AU: Gnanadesikan,-A.
AF: Prog. in Atmos. and Oceanic Sci., Princeton Univ., Princeton, NJ 08540, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1996 vol. 101, no. C5, pp. 12,177-12,191
LA: English
ER: M (Marine)
AB: As carbon monoxide within the oceanic surface layer is produced by solar radiation, diluted by mixing, consumed by biota, and outgassed to the atmosphere, it exhibits a diurnal cycle. The effect of dilution and mixing on this cycle is examined using a simple model for production and consumption coupled to three different mixed layer models. The magnitude and timing of the peak concentration, the magnitude of the average concentration, and the air-sea flux are considered. The models are run through a range of heating and wind stress and compared to experimental data reported by Kettle [1994]. The models are run to simulate a single day of observations. The mixing parameterization is shown to be very important, with a model which mixes using small-scale diffusion producing markedly larger surface concentrations than models which homogenize the mixed layer completely and instantaneously.
AN: 3960073
20 of 1521
TI: Biogeochemical cycling in the global ocean. 2. New production, Redfield ratios, and remineralization in the organic pump
AU: Shaffer,-G.
AF: Dep. Geophys., Niels Bohr Inst. for Astronomy, Phys., and Geophys. Univ. Copenhagen, Copenhagen, Denmark
SO: J.-GEOPHYS.-RES.-C-OCEANS 1996 vol. 101, no. C2, pp. 3723-3745
LA: English
ER: M (Marine)
AB: Analytic solutions for global ocean distributions of phosphate, nitrate, and dissolved oxygen are presented for the high-latitude exchange/interior diffusion-advection (HILDA) model. The organic pump, which together with ocean physics controls nutrient and oxygen cycling in the ocean, is characterized in the model by parameters representing element (Redfield) ratios of organic matter exported from the lighted surface layer of the ocean and by parameters representing depth scales of remineralization for each element. A critical reassessment of recent work on determining Redfield ratios in new production and remineralization ratios is presented. From this reassessment and from the more robust results of this paper, the following conclusions are reached: (1) Total ocean new production is probably at least 5 Gt C yr super(-1). (2) The best estimate for ocean mean -O sub(2):C:N:P mole ratios in new production is about 148:105:15:1. (3) Significant vertical fractionation of organic matter occurs in the upper kilometer or so of the ocean; nutrients are released in the mean faster than carbon dioxide. Mean remineralization ratios for -O sub(2):P (C:P) increase from about 130 plus or minus 15 (90 plus or minus 15) at the base of the euphotic zone to about 170 plus or minus 10 (125 plus or minus 10) at 1000- to 1500-m depth and remain so deeper down. (4) The organic matter exported out of the surface layer of the high-latitude oceans is relatively poor in nitrogen but relatively rich in hydrogen.
AN: 3960053
21 of 1521
TI: Atmospheric sulfur cycling in the Tropical Pacific marine boundary layer (12 degree S, 135 degree W): A comparison of field data and model results. 2. Sulfur dioxide
AU: Yvon,-S.A.; Saltzman,-E.S.
AF: Natl. Oceanic and Atmos. Admin., Climate Monitoring and Diagnostics Lab., Boulder, CO, USA
SO: J.-GEOPHYS.-RES.-D-ATMOS. 1996 vol. 101, no. D3, pp. 6911-6918
NT: Special section: GEWEX Continental-scale International Project (GCIP).
LA: English
ER: M (Marine)
AB: The atmospheric chemistry of sulfur dioxide over the tropical South Pacific Ocean is investigated by using results from field measurements and numerical models. Simultaneous real time measurements of sulfur dioxide and its biogenic precursor dimethylsulfide were made at 12 degree S, 135 degree W for a 6-day period from March 3 through March 9, 1992. The mean SO sub(2) and DMS mole fractions were 71 plus or minus 56 pmol mol super(-1) (1 sigma ) and 453 plus or minus 93 pmol/mol (1 sigma ) respectively. These concentrations are compared to those predicted by a time-dependent photochemical box model of the marine boundary layer. Model estimates of the yield of SO sub(2) from DMS oxidation range from 27% to 54%. Even with low yields, DMS is the dominant source of SO sub(2) in this region. Estimates of vertical entrainment velocities based on the tropospheric ozone budget suggest that vertical entrainment is a minor source of SO sub(2). The relative rates of various loss mechanisms for SO sub(2) are dry deposition to the sea surface (58%), in-cloud oxidation (9%), OH oxidation (5%), and uptake by sea-salt aerosols (28%).
AN: 3953816
22 of 1521
TI: Atmospheric sulfur cycling in the Tropical Pacific marine boundary layer (12 degree S, 135 degree W): A comparison of field data and model results. 1. Dimethylsulfide
AU: Yvon,-S.A.; Saltzman,-E.S.; Cooper,-D.J.; Bates,-T.S.; Thompson,-A.M.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Univ. Miami, Miami, FL, USA
SO: J.-GEOPHYS.-RES.-D-ATMOS. 1996 vol. 101, no. D3, pp. 6899-6909
NT: Special section: GEWEX Continental-scale International Project (GCIP).
LA: English
ER: M (Marine)
AB: Shipboard measurements of atmospheric and seawater DMS were made at 12 degree S, 135 degree W for 6 days during March 1992. The mean seawater DMS concentration during this period was 4.1 plus or minus 0.45 nM (1 sigma , n = 260) and the mean atmospheric DMS mole fraction was 453 plus or minus 93 pmol/mol (l sigma , n = 843). Consistent atmospheric diel cycles were observed, with a nighttime maximum and daytime minimum and an amplitude of approximately 85 pmol/mol. Photochemical box model calculations were made to test the sensitivity of atmospheric DMS concentrations to the following parameters: 1) sea-to-air flux, 2) boundary layer height, 3) oxidation rate, and 4) vertical entrainment velocities. The observed relationship between the mean oceanic and atmospheric DMS levels require the use of an air-sea exchange coefficient which is at the upper limit end of the range of commonly used parameterizations. The amplitude of the diel cycle in atmospheric DMS is significantly larger than that predicted by a photochemical model. This suggests that the sea-to-air DMS flux is higher than was previously thought, and the rate of daytime oxidation of DMS is substantially underestimated by current photochemical models of DMS oxidation.
AN: 3953815
23 of 1521
TI: Biogeochemical cycles of selenium in Antarctic water
AU: Weiping,-Xia; Haishen,-Zhang; Jianan,-Tan
AF: Dep. Oceanogr., Old Dominion Univ., Norfolk, VA 23529, USA
SO: J.-ENVIRON.-SCI.-CHINA 1996 vol. 8, no. 1, pp. 120-126
LA: English
ER: M (Marine)
AB: Both vertical and horizontal profiles of total dissolved selenium, dissolved organic and inorganic selenium, including Se(IV) and Se(VI), as well as particulate selenium in seawater were obtained on a basis of newly developed separation technique form Antarctic Ocean, where the production of deep waters occurs. The results exhibited that the concentrations of Se(IV) and Se(VI) were elevated and the total concentration in the surface of the high latitude waters (1.31 nmol/L) was above those at lower latitudes (1.09 nmol/L) and also that previously reported from the Southern Ocean (1.18 nmol/L, Suzuki, 1987). Preliminary investigation using specifically designed microlayer-sampler, that was first employed to identify the main biogeochemical processes, revealed Antarctic Ocean being functioning as a potential source as selenium in sea-air exchange. The mean life time of the selenium, detected as Se(IV) in deep water, was also estimated rather shorter than the residence time of the water mass, based on the samples collected from the cruise of China's Sixth Scientific Expedition.
AN: 3952281
24 of 1521
TI: Metazooplankton distribution in the Pomeranian Bay (southern Baltic) -- species composition, biomass and respiration
AU: Postel,-L.; Mumm,-N.; Krajewska-Soltys,-A.
AF: Institute of Baltic Sea Research Rostock-Warnemuende, Seestrasse 15, D 18119 Rostock-Warnemuende, Germany
SO: BIUL.-MORSK.-INST.-RYBACK.-GDYNIA-BULL.-SEA-FISH.-INST.-GDYNIA 1995 vol. 136, no. 3, pp. 61-73
LA: English
ER: M (Marine)
AB: The major objective of this study was to assess the importance of metazooplankton for organic matter transformations under the influence of spatial gradients in environmental conditions between the Odra River estuary and the open Baltic Sea. Zooplankton was collected in the fall of 1993, and net samples were sieved into size fractions for determinations of dry weight, species composition, and respiration. Cluster analysis revealed 4 major zooplankton assemblages: 1) a river plume, where limnetic rotifers, cladocerans, and cyclopoids acquired a high numerical importance, 2) a coastal transition zone characterized by a frequent occurrence of meroplankton larvae, 3) an outer transition zone dominated by copepods and cladocerans, and 4) an assemblage typical of open Arkona Sea conditions, almost exclusively consisting of copepods. In general, the biomass tended to decline with increasing distance from the river outlet, from 140 mg/m super(3) to open sea levels of about 40 mg/m super(3). However, a sharp drop in the biomass to 10 mg/m super(3) was observed near the border of fresh water influence, reflecting the disappearance of limnetic species. The average dry mass specific respiration rate decreased with increasing size class from 3.62 to 1.79 mu l O sub(2)/mg/h. Due to the low biomass of the smallest size class, in situ respiration was mainly a function of dry mass concentration. Total respiration in 55-500 mu m decreased from about 10 to 3 ml O sub(2)/m super(3)/day with increasing distance to the river mouth. This tendency was superimposed by a strong decline to 1 ml O sub(2)/m super(3)/day near the front of the river plume. In terms of carbon utilization, in situ respiration corresponds to 1-2% of primary production. This low percentage, which is rather typical of spring bloom conditions, results mainly from low dry mass specific respiration, despite high primary production, chlorophyll a concentration, and temperature. One possible explanation for this obvious inconsistency would be that seasonal variations in metabolic activity are not controlled by temperature and/or food conditions alone, but also by the biological constitution of plankton organisms.
AN: 3950799
25 of 1521
TI: Confirmation of iron limitation of phytoplankton photosynthesis in the Equatorial Pacific Ocean
AU: Behrenfeld,-M.J.; Bale,-A.J.; Kolber,-Z.S.; Aiken,-J.; Falkowski,-P.G.
AF: Oceanogr. and Atmos. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973-5000, USA
SO: NATURE 1996 vol. 383, no. 6600, pp. 508-511
LA: English
ER: M (Marine)
AB: The eastern Equatorial Pacific Ocean is one of only three open-ocean regions where low phytoplankton chlorophyll biomass persists despite perennially high nitrate and phosphate nutrient concentrations. In 1993, an area within this region was artificially enriched with a single dose of soluble iron to test whether phytoplankton are physiologically prevented from utilizing the available nutrients by the low natural iron concentrations. Although photosynthesis was stimulated, the observed lack of a bloom or a significant decrease in nutrient concentrations could not be attributed unequivocally to zooplankton grazing, further iron limitation or secondary nutrient limitation. In 1995, a second iron-enrichment experiment (IronEx II) was conducted in which the same total dosage of iron was added, but over eight days. A massive phytoplankton bloom developed, significantly reducing surface-water nutrient and CO sub(2) concentrations. Here we report in situ measurements of fluorescence during IronEx II, which show that the iron enrichment triggered biophysical alterations of the phytoplankton's photosynthetic apparatus, resulting in increased photosynthetic capacities throughout the experiment and, hence, the observed bloom. These results unequivocally establish physiological limitation of phytoplankton by iron as the cause of the high-nitrate, low-chlorophyll phenomenon in this ocean region.
AN: 3950484
26 of 1521
TI: Large decrease in ocean-surface CO sub(2) fugacity in response to in situ iron fertilization
AU: Cooper,-D.J.; Watson,-A.J.; Nightingale,-P.D.
AF: Dep. Atmos. and Oceanic Sci., Univ. Wisconsin, 1225 West Dayton St., Madison, WI 53706, USA
SO: NATURE 1996 vol. 383, no. 6600, pp. 511-513
LA: English
ER: M (Marine)
AB: The Equatorial Pacific Ocean is a "high-nitrate, low-chlorophyll" region where nitrate and phosphate are abundant all year round. These nutrients cannot therefore be limiting to phytoplankton production. It has been suggested that the bioavailability of iron--a micronutrient--may be preventing full biological utilization of the major nutrients. The results of a previous in situ iron fertilization experiment in this region provided support for this hypothesis, but the observed biological response resulted in only a small decrease in surface-water CO sub(2) fugacity. Here we report a much larger, biologically induced uptake of surface-water CO sub(2) that occurred during a second study. The fugacity of CO sub(2) in the centre of the (iron-fertilized) patch of surface ocean fell from a background value near 510 mu atm to approximately 420 mu atm, corresponding to a transient 60% decrease in the natural ocean-to-atmosphere CO sub(2) flux. We conclude that iron supply to this ocean region can strongly modulate the local short-term source of CO sub(2) to the atmosphere, but has little long-term influence on atmospheric CO sub(2) partial pressure. However, if such a modulation also occurs in the Southern Ocean, then iron bioavailability at high southern latitudes could have a significant effect on atmospheric CO sub(2) partial pressure, for example over glacial-interglacial periods.
AN: 3950482
27 of 1521
TI: Increased dimethyl sulphide concentrations in sea water from in situ iron enrichment
AU: Turner,-S.M.; Nightingale,-P.D.; Spokes,-L.J.; Liddicoat,-M.I.; Liss,-P.S.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: NATURE 1996 vol. 383, no. 6600, pp. 513-517
LA: English
ER: M (Marine)
AB: The concentrations of bioavailable iron in the surface waters of some ocean regions may indirectly modulate climate by controlling phytoplankton productivity and thus the amounts of carbon dioxide and dimethyl sulphide (DMS) that are exchanged with the atmosphere. Oxidation of DMS is involved in the formation of atmospheric sulphate particles, which can exert a climate cooling effect directly (by scattering and absorbing solar radiation), and indirectly (by affecting cloudiness and hence global albedo). But direct evidence supporting the hypothesis that DMS production in the ocean is affected by iron availability is lacking. Here we report changes in the concentrations of DMS in response to in situ iron-enrichment during two ecosystem-scale experiments designed to investigate the biological and chemical effects of iron fertilization of under-productive surface ocean waters. The first such experiment revealed a limited overall biological response and no significant changes in DMS concentrations, although the concentrations of its biochemical precursor doubled. The second experiment, designed to better mimic the natural process of iron enrichment, elicited a much stronger biological response, and DMS concentrations increased by a factor of 3.5. This result provides direct support for an important link in the iron--DMS--climate hypothesis.
AN: 3950481
28 of 1521
TI: A massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the Equatorial Pacific Ocean
AU: Coale,-K.H.; Johnson,-K.S.; Fitzwater,-S.E.; Gordon,-R.M.; Tanner,-S.; Chavez,-F.P.; Ferioli,-L.; Sakamoto,-C.; Rogers,-P.; Millero,-F.; Steinberg,-P.; Nightingale,-P.; Cooper,-D.; Cochlan,-W.P.; Kudela,-R.
AF: Moss Landing Lab., P.O. Box 450, Moss Landing, CA 95039-0450, USA
SO: NATURE 1996 vol. 383, no. 6600, pp. 495-501
LA: English
ER: M (Marine)
AB: The seeding of an expanse of surface waters in the Equatorial Pacific Ocean with low concentrations of dissolved iron triggered a massive phytoplankton bloom which consumed large quantities of carbon dioxide and nitrate that these microscopic plants cannot fully utilize under natural conditions. These and other observations provide unequivocal support for the hypothesis that phytoplankton growth in this oceanic region is limited by iron bioavailability.
AN: 3950479
29 of 1521
TI: Global carbon exchange and methane emissions from natural wetlands: Application of a process-based model
AU: Cao,-M.; Marshall,-S.; Gregson,-K.
AF: Dep. Physiol. and Environ. Sci., Univ. Nottingham, Loughborough, England, UK
SO: J.-GEOPHYS.-RES.-D-ATMOS. 1996 vol. 101, no. D9, pp. 14,399-14,414
LA: English
ER: F (Freshwater)
AB: Wetlands are one of the most important sources of atmospheric methane (CH sub(4)), but the strength of this source is still highly uncertain. To improve estimates of CH sub(4) emission at the regional and global scales and predict future variation requires a process-based model integrating the controls of climatic and edaphic factors and complex biological processes over CH sub(4) flux rates. This study used a methane emission model based on the hypothesis that plant primary production and soil organic matter decomposition act to control the supply of substrate needed by methanogens; the rate of substrate supply and environmental factors, in turn, control the rate of CH sub(4) production, and the balance between CH sub(4) production and methanotrophic oxidation determines the rate of CH sub(4) emission into the atmosphere. Coupled to data sets for climate, vegetation, soil, and wetland distribution, the model was used to calculate spatial and seasonal distributions of CH sub(4) emissions at a resolution of 1 degree latitude x 1 degree longitude. The calculated net primary production (NPP) of wetlands ranged from 45 g C m super(-2) yr super(-1) for northern bogs to 820 g C m super(-2) yr super(-1) for tropical swamps. CH sub(4) emission rates from individual gridcells ranged from 0.0 to 661 mg CH sub(4) m super(-2) d super(-1), with a mean of 40 mg CH sub(4) m super(-2) d super(-1) for northern wetland, 150 mg CH sub(4) m super(-2) d super(-1) for temperate wetland, and 199 mg CH sub(4) m super(-2) d super(-1) for tropical wetland. Total CH sub(4) emission was 92 Tg yr super(-1). Sensitivity analysis showed that the response of CH sub(4) emission to climate change depends upon the combined effects of soil carbon storage, rate of decomposition, soil moisture and activity of methanogens.
AN: 3950389
30 of 1521
TI: Global forest systems: An uncertain response to atmospheric pollutants and global climate change?
AU: Dixon,-R.K.; Wisniewski,-J.
AF: U.S. Support for Country Stud. to Address Climate Change, PO-63, 100 Independence Ave., SW, Washington, DC 20585, USA
CO: 5. Int. Conf. on Acidic Deposition: Science and Policy, Goteborg (Sweden), 26-30 Jun 1995
SO: ACID-REIGN-'-95?-PROCEEDINGS-FROM-THE-5TH-INTERNATIONAL-CONFERENCE-ON-ACIDIC-DEPOSITION:-SCIENCE-AND-POLICY-HELD-IN-GOTEBORG,-SWEDEN,-26-30-JUNE-1995. Grennfelt,-P.;Rodhe,-H.;Thoerneloef,-E.;Wisniewski,-J.-eds. 1995 vol. 85, no. 1 pp. 101-110
ST: WATER,-AIR,-SOIL-POLLUT. vol. 85, no. 1
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Forest systems cover more than 4.1 x 10 super(9) ha of the Earth's land area. The future response and feedbacks of forest systems to atmospheric pollutants and projected climate change may be significant. Boreal, temperate and tropical forest systems play a prominent role in carbon (C), nitrogen (N) and sulfur (S) biogeochemical cycles at regional and global scales. The timing and magnitude of future changes in forest systems will depend on environmental factors such as a changing global climate, an accumulation of CO sub(2) in the atmosphere, and increase global mineralization of nutrients such as N and S. The interactive effects of all these factors on the world's forest regions are complex and not intuitively obvious and are likely to differ among geographic regions. Although the potential effects of some atmospheric pollutants on forest systems have been observed or simulated, large uncertainty exists in our ability to project future forest distribution, composition and productivity under transient or nontransient global climate change scenarios. The potential to manage and adapt forests to future global environmental conditions varies widely among nations. Mitigation practices, such as liming or fertilization to ameliorate excess NO sub(x) or SO sub(x) or forest management to sequester CO sub(2) are now being applied in selected nations worldwide.
AN: 3950128
31 of 1521
TI: Methane budget from paddy fields in India
AU: Parashar,-D.C.; Mitra,-A.P.; Gupta,-P.K.; Rai,-J.; Sharma,-R.C.; Singh,-N.; Koul,-S.; Ray,-H.S.; Das,-S.N.; Parida,-K.M.; Rao,-S.B.; Kanungo,-S.P.; Ramasami,-T.; Nair,-B.U.; et-al.
AF: Natl. Phys. Lab. (NPL), Dr. K.S. Krishnan Rd., New Delhi-110012, India
SO: CHEMOSPHERE 1996 vol. 33, no. 4, pp. 737-757
LA: English
AB: Results of national methane campaign launched in 1991 to assess methane budget from Indian paddy fields are reported. The campaign involved a number of scientific institutions and universities with National Physical Laboratory at Delhi operating as a nodal agency and covered most of the major rice growing regions of India. Methane emission rates ranged between -0.64 and 84.1 mg m super(-2)h super(-1). The methane budget from Indian paddies has been estimated to be around 4.0 TgY super(-1) with a range between 2.7 to 5.4 TgY super(-1).
AN: 3948300
32 of 1521
TI: Redfield ratios and regeneration rates of particulate matter in the Sea of Japan as a model of closed system
AU: Chen,-C.-T.A.; Gong,-Gwo-Ching; Wang,-Shu-Lun; Bychkov,-A.S.
AF: Inst. Mar. Geol. and Chem., Natl. Sun Yat-Sen Univ., Kaohsiung, Taiwan
SO: GEOPHYS.-RES.-LETT. 1996 vol. 23, no. 14, pp. 1785-1788
LA: English
ER: M (Marine)
AN: 3945802
33 of 1521
TI: Bio-optical modeling of photosynthetic production in coastal waters
AU: Smith,-R.C.; Prezelin,-B.B.; Bidigare,-R.R.; Baker,-K.S.
AF: CSL/Cent. Remote Sensing and Environ. Opt, UCMBO Geogr. Dep., Univ. California at Santa Barbara, Santa Barbara, CA 93106, USA
SO: LIMNOL.-OCEANOGR. 1989 vol. 34, no. 8, pp. 1524-1544
NT: Special issue: Hydrologic optics.
LA: English
ER: M (Marine)
AB: A physiological-based bio-optical model is used to estimate vertical profiles of instantaneous, diurnal, and integrated daily rates of in situ primary production throughout the water column at three stations across a coastal front. The model makes use of an empirical relationship between photosynthesis, quantum yield, and photosynthetically absorbed radiation and is a full spectral model with all relevant parameters determined as a function of wavelength. In the prior application of this bio-optical model, parameters used to estimate quantum yield as a function of irradiance were wavelength-independent and held constant. Here, the model is recast so that quantum yield is estimated with wavelength-dependent photosynthesis-irradiance (P-I) parameters, P sub(max) the maximum rate of phytoplankton photosynthesis, and I sub(k) the P-I saturation parameter, which are allowed to vary with depth and time of day. Both P sub(max)-dependent (assumed to be lambda -independent) and I sub(k)-dependent (known to be lambda -dependent) estimates of temporal/spatial changes in quantum yield were assessed. The model was tested in water masses where a net-to-nanoplankton transition was occurring in phytoplankton communities dominated by diatoms and prymnesiophytes. At each station there is close agreement between super(14)C productivity estimates derived from knowledge of diurnal patterns in P-I parameters and productivity estimates derived from two variants of the bio-optical model based on knowledge of spectral irradiance and phytoplankton pigmentation. The super(14)C and bio-optical estimates of primary production also show similar vertical patterns for either instantaneous or daily integrated values. When compared with super(14)C estimates, I sub(k)-dependent bio-optical estimates of photosynthetic rates give a closer match than bio-optical estimates that are P sub(max)-dependent. The model permits calculation of primary production from shipboard observations and may be useful for predicting production rates from bio-optical data provided by untended buoys. (DBO)
AN: 3945026
34 of 1521
TI: The role of heterotrophic bacteria in iron-limited ocean ecosystems
AU: Tortell,-P.D.; Maldonado,-M.T.; Price,-N.M.
AF: Dep. Ecol. and Evol. Biol., Princeton Univ., Princeton, NJ 08544, USA
SO: NATURE 1996 vol. 383, no. 6598, pp. 330-332
LA: English
ER: M (Marine)
AB: Iron availability limits phytoplankton growth in large areas of the world's oceans and may influence the strength of the biological carbon pump. Very little is known of the iron requirements of oceanic heterotrophic bacteria, which constitute up to 50% of the total particulate organic carbon in open ocean waters and are important in carbon cycling as remineralizers of dissolved organic matter and hence producers of CO sub(2). Here we report that oceanic bacteria contain more iron per biomass than phytoplankton. In the subarctic Pacific, they constitute a large fraction of biogenic iron and account for 20-45% of biological iron uptake. Bacterial iron quotas in the field are similar to those of iron-deficient laboratory cultures, which exhibit reduced electron transport, slow growth, and low carbon growth efficiency. Heterotrophic bacteria therefore play a major role in the biogeochemical cycling of iron. In situ iron limitation of heterotrophic metabolism may have profound effects on carbon flux in the ocean.
AN: 3944722
35 of 1521
TI: TAG hydrothermal field
AU: Humphris,-S.E.; Herzig,-P.M.; Miller,-J.
AF: Dep. Geol. and Geophysics, Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: JOIDES-J. 1995 vol. 21, no. 2, pp. 8-15
LA: English
ER: M (Marine)
AB: Leg 158 investigated the fluid flow, geochemical fluxes and associated alteration and mineralization, microbiological processes, and the subsurface nature of an active hydrothermal system on a slow-spreading sediment-free mid-ocean ridge. The active mound within the Trans-Atlantic Geotraverse (TAG) hydrothermal field at 26 degree N latitude on the Mid-Atlantic Ridge (MAR) is a large, mature deposit of varying mineralogy with emanating fluids displaying a wide range of temperatures and two distinct, but related, chemistries. At Site 957, a northwest-southeast transect of holes in three major, distinct areas of the mound was drilled: the upper terrace east of the Black Smoker Complex (proposed TAG-1 area), the white smoker Kremlin area (proposed TAG-2 area), and the upper terrace west of the Black Smoker Complex (proposed TAG-4 area). Based on the sequence of rock types recovered from each area, four major lithologic types can be distinguished, all of which may or may not be present at a given location. Massive pyrites and pyrite breccias dominate the upper 10-20 m. This is followed by an anhydrite-rich zone, which is composed of matrix-supported pyrite- anhydrite breccias and pyrite-anhydrite-silica breccias. At depths of about 40-45 mbsf, the amount of quartz-pyrite mineralization and quartz veining increases and represents the top of the quartz-sulfide stockwork zone, which typically includes pyrite-silica breccias overlying silicified wall-rock breccias. A quartz-chlorite stockwork zone was sampled at depths greater than 100 mbsf in Hole 957E. This complex assemblage of rock types is a product of the multistage development of the mound, and is reflected in the sequences of alteration and veining events that can be distinguished both in the sulfide breccias and in the silicified wall-rock and chloritized basalt breccias.
AN: 3943060
36 of 1521
TI: Preface to tropical coastal sedimentary environments
AU: Nittrouer,-C.; Figueiredo,-A.
SO: GEO-MAR.-LETT. 1996 vol. 16, no. 1, pp. 1-2
NT: Special issue: Tropical coastal sedimentary environments.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Coastal oceanographers around the world need to recognize the importance of tropical settings to the global ocean and articulate this to organizations that support international scientific research. Major research studies should be designed for tropical coastal environments, similar to those studies being undertaken in higher latitude coastal settings and in deep-sea equatorial settings. The wet tropics, in particular, have a significant influence on the world ocean; unfortunately, geopolitical circumstances deny them a powerful voice to bring about concerted efforts for scientific investigation. Therefore, we urge the international scientific community not to forget the wet tropics. This volume is an example of the international community at work. It is an outgrowth of two meetings convened in 1993. One was held at Universidade Federal Fluminense (A. G. Figueiredo and C. A. Nittrouer, conveners) and focused on the Brazilian coastal ocean at the mouth of the Amazon River. The other meeting was held at the Australian Institute of Marine Science (G. J. Brunskill and C. A. Nittrouer, conveners) and primarily considered the Gulf of Papua (southern coast of Papua New Guinea) with contrasts to the Amazon coastal area. This collection of papers represents contributions from both meetings. Unfortunately, the length of the volume required it to be split into two parts, appearing in Geo-Marine Letters as a final double issue of 1995 (v. 15) and the first issue of 1996 (v. 16).
AN: 3941050
37 of 1521
TI: Decomposition along a bog to rich fen gradient in central Alberta, Canada
AU: Szumigalski,-A.R.; Bayley,-S.E.
AF: Dep. Biol. Sci., CW405 Biol. Sci. Bldg., Univ. Alberta, Edmonton, AB T6G 2E9, Canada
SO: CAN.-J.-BOT.-REV.-CAN.-BOT. 1996 vol. 74, no. 4, pp. 573-581
LA: English
ER: F (Freshwater)
AB: The carbon (C) and nitrogen (N) contents and decomposition rates of the aboveground litter were measured in five peatlands (bog, poor fen, open moderately rich fen, wooded moderately rich fen, and lacustrine sedge fen) in central Alberta, Canada, over a period of 2 years. Decay rates and C and N content of the dominant species were measured at each site. Weight losses after 1 and 2 years were negatively correlated with initial and final C/N ratios. Weight losses were positively correlated with initial and final %N, with the fastest weight losses in the species with the highest N content. Rates of decay within sites differed according to litter types, with Carex > Betula > mosses. Decay rates and C and N content were also determined for a standard litter type (Carex lasiocarpa), to make cross-site comparisons. Standard litter weight losses differed between sites after 1 and 2 years of decay. The sites ranked poor fen > wooded-rich fen > bog > open-rich fen > sedge fen in order of greatest to smallest percent weight loss after 2 years. After 1 year, weight loss of the standard litter was negatively correlated with water level and pH-related parameters and positively correlated with total dissolved P. Decomposition was correlated with both substrate quality and environmental parameters, but the former may be more important than the latter in controlling decomposition in these peatlands.
AN: 3940642
38 of 1521
TI: Aspects of the biogeochemistry of sulphur in glacial melt water ponds on the McMurdo Ice Shelf, Antarctic
AU: De-Mora,-S.J.; Lee,-P.A.; Grout,-A.; Schall,-C.; Heumann,-K.G.
AF: Dep. Oceanographie, Univ. Quebec a Rimouski, 300 allee des Ursulines, Rimouski, Quebec, Canada
SO: ANTARCT.-SCI. 1996 vol. 8, no. 1, pp. 15-22
LA: English
ER: F (Freshwater)
AB: The distribution of dimethylsulphide (DMS), together with the precursor dimethylsulphonio-propionate (DMSP) and the oxidation product dimethylsulphoxide (DMSO), was measured in melt waters on the McMurdo Ice Shelf in the immediate vicinity of Bratina Island. Conductivity in these sulphate dominated ponds was extremely variable, ranging from 0.106-52.3 mS cm super(-1). Similarly, chlorophyll a concentrations in the pond waters (1-150 mu g l super(-1)) and mats (1.4-33 mu g cm super(-2)) differed considerably. The biomass was dominated by benthic felts of phototrophic cyanobacteria, which might act as a source of biogenic sulphur compounds in the ponds. The mean (and ranges) of concentrations of dissolved sulphur compounds (nmol l super(-1)) were: CS sub(2) 0.16 (<0.04-1.20); DMSP sub(d) 0.6 (<0.07-8.4); DMS 3.5 (<0.07-183); DMSO 27.9 (15.5-184.5). Very high concentrations of DMSO were ubiquitous in the ponds in the ice-cored moraine region of the ice shelf, with dissolved concentrations having been 1-2 orders of magnitude greater than those of DMS or DMSP sub(d). It is difficult to ascribe the formation of DMSO solely to the conventionally accepted pathways of DMS oxidation by either bacterial activity or photochemical reactions. A direct biosynthetic production from phytoplankton or bacteria might be involved which means that DMSO in aquatic environments could act as a significant source of DMS rather than as a sink as generally supposed.
AN: 3938807
39 of 1521
TI: [Modelling the biogeochemical cycle of the elements limiting the primary production in the English Channel (N, P, Si).]
OT: Modelisation du cycle biogeochimique des elements limitant la production primaire en Manche (N, P, Si)
AU: Hoch,-T.
CA: Univ. Paris 7, (France)
SO: PARIS-FRANCE UNIV.-PARIS-7 1995 213 pp
LA: French
ER: M (Marine)
AB: This work presents a model of organic matter cycle in the English Channel, through the nitrogen, phosphorous and silicium cycles. These elements were chosen for that they are limitant factors for the primary production in the Channel. In a first approach, a physical sub-model in boxes has been retained. The "ELISE" logiciel cutted the Channel into 71 boxes between which water fluxes were automatically calculated. This model has been associated to a two-layer vertical thermo-haline model, that simule temperature and salinity in the surface, also in the bottom layers. A biogeochemical model considers nitrogen, phosphorus and silicium into their mineral forms, also into their organic (phytoplanktonic), detritic in the water column, and organic benthic forms. Results of the coupling of the two models show influence of the stratification, of thermal origin in the Western Channel, and haline in the Bay of Seine upon phytoplankton distribution. Phytoplankton grow better in shallow water zones and in the surface layer of stratified zones, where the low thickness of the water let light penetrate at the best. The spring bloom is determined by these criteria, but the strengh of the bloom depends on the chemical richness of the environment. High concentration are also remarked at the opening of the Seine Estuary and along the french coast of the Eastern Channel. Raw annual primary production is strongly influenced by vertical structure, but in a quasi-opposite pattern as the spring bloom. The higher productions are recorded in the middle of the Eastern Channel that are depth mixed depth zones. The "ELISE" model was used to make a sensiblity analysis of the ecological processes at their limits, and of the forcing variables. Terrigenous nutriments inputs to the sea show that rivers have a little but remarkable role. The Seine river is by far the most important of these inputs. Nitrogen and phosphorous were analysed separately, and it is shown that the primary production is dependant of the nitrogen input. A long-term meteorological simulation (1978-1992) was initiated, and show strong dependance of the ecosystem towards meteorological conditions. They determine not only temperature and solar radiation used by phytoplankton, but also the vertical structure and possible stratification. Multi-years variations of the Seine inputs are only sensible upon the Picardie coastal zone. An assay of coupling this biological model with a physical fine model show the results of a pseudo-3D simulation. Such results are more precise as in the preceding conditions, but confirm the general conclusions.
AN: 3938628
40 of 1521
TI: The estimation of current state of Lake Ladoga using mathematical models
AU: Leonov,-A.V.; Filatov,-N.N.; Titov,-V.S.
AF: Water Problems Inst., Russian Acad. Sci., N. Basmannay Str. 10, 107078, Moscow, Russia
CO: 1. Int. Lake Ladoga Symp., St. Petersburg (Russia), 22-26 Nov 1993
SO: PROCEEDINGS-OF-THE-FIRST-INTERNATIONAL-LAKE-LADOGA-SYMPOSIUM:-ECOLOGICAL-PROBLEMS-OF-LAKE-LADOGA-HELD-IN-ST.-PETERSBURG,-RUSSIA,-22-26-NOVEMBER-1993. Simola,-H.;Viljanen,-M.;Slepukhina,-T.;Murthy,-R.-eds. 1996 vol. 322, no. 1-3 pp. 103-108
ST: HYDROBIOLOGIA vol. 322, no. 1-3
LA: English
ER: F (Freshwater)
AB: This paper describes a mathematical simulation model of the transformation of organic matter and biogenic compounds. The model is validated with observations made on Lake Ladoga. Despite the approximate nature of the biogenic load data, a good agreement is obtained between the calculated substance concentrations and available observations made during individual seasons for different areas of the lake. The model was developed by the author Leonov and this paper presents new model results with accurate formulations for nitrogen and carbon components. Comparison with observational data base collected during 1976-1979 shows that the model results provide good simulation of the annual seasonal changes in material concentrations in the identified regions of the lake.
AN: 3932181
41 of 1521
TI: The biogeochemical cycling of Zn, Cu, Fe, Mn, and dissolved organic C in a seasonally anoxic lake
AU: Hamilton-Taylor,-J.; Davison,-W.; Morfett,-K.
AF: Inst. Environ. and Biol. Sci., Lancaster Univ., Lancaster LA1 4YQ, UK
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 3, pp. 408-418
LA: English
ER: F (Freshwater)
AB: Detailed time-depth distributions of dissolved Zn, Cu, Fe, Mn, and dissolved organic C (DOC), together with pH, were obtained for the water column and near-surface sediment pore waters of a seasonally anoxic lake (Esthwaite Water, U.K.) over a 1-yr period. Dissolved Fe and Mn followed well-known patterns linked to redox recycling. The variation in DOC resulted mostly from its coupling with Fe, DOC being coprecipitated with Fe oxide and released into solution on the reductive remobilization of the oxide. This process produced a >7-fold seasonal variation in DOC concentrations in the pore waters, with a maximum of similar to 7 mg/liter. Dissolved Zn and Cu exhibited coherent and similar distribution patterns unrelated in any simple way to the distributions of dissolved Fe and Mn, pH, and DOC. The most ubiquitous feature of the distribution of dissolved Zn, and to a lesser degree that of dissolved Cu, was a concentrations maximum at the sediment-water interface, which disappeared completely only when anoxia was maximal in mid- and late summer. The interfacial maxima were attributed to rapid release from freshly deposited particles allied to sulfide precipitation in the sediments. The timing of events, associated with an increase in interfacial dissolved Cu and Zn concentrations before and during a period of ice cover, indicated that the Cu was derived from Fe and possibly Mn oxides and Zn from planktonic algae. The cumulative downward diffusive fluxes of Zn and Cu from the interfacial maxima were unimportant ( similar to 1% of total) compared to total metal sedimentation rates. Chemical equilibrium calculations indicated that Zn- and Cu-sulfide complexes dominated in the pore waters under reducing conditions, with humic binding being insignificant, and that precipitation as pure sulfides or coprecipitation with FeS were likely major removal processes for Zn and Cu under anoxic conditions.
AN: 3931599
42 of 1521
TI: Loading and utilization of dissolved organic carbon from emergent macrophytes
AU: Mann,-C.J.; Wetzel,-R.G.*
AF: Dep. Biol. Sci., Univ. Alabama, Tuscaloosa, AL 35487-0206, USA
SO: AQUAT.-BOT. 1996 vol. 53, no. 1-2, pp. 61-72
LA: English
ER: F (Freshwater)
AB: The very high productivity of emergent macrophytes can provide major sources of dissolved organic matter to recipient aquatic ecosystems. Leachate was collected from live and senescent tissues of Juncus effusus L. and Typha latifolia L. and analyzed for dissolved organic carbon (DOC; mg C/l/cm super(2) surface area) and its availability to wetland bacteria. Leachate DOC ranged from 1.9 to 5.2 mg C/l cm super(2) across a gradient of fully photosynthetic to fully senescent culms. In culms 1/4 to 3/4 senescent, there was no significant difference (P > 0.05) in leachate DOC concentrations between the photosynthetic and senescent portions of culms. DOC in the leachate of J. effusus culms decreased significantly (P < 0.05) from an average of 336.8 mg C/l cm super(2) in January 1994 to 68.3 mg C/l/cm super(2) in July 1994. Bacterial growth efficiencies (ratio of bacterial biomass produced, measured by [ super(3)H] leucine incorporation, to leachate DOC utilized) on the leachate of J. effusus ranged from 16 to 34%. DOC concentrations in the leachate from T. latifolia were 1.4 (photosynthetic leaves) and 145.3 (senescent leaves) mg C/l cm super(2) and supported bacterial efficiencies of 45% (photosynthetic leaves) and 4% (senescent leaves), respectively.
AN: 3931575
43 of 1521
TI: The biogeochemistry of lipids in rivers of the Orinoco Basin
AU: Jaffe,-R.; Wolff,-G.A.; Cabrera,-A.C.; Chitty,-H.C.
AF: Florida Intl. Univ., Drinking Water Res. Cent., University Park, Miami, FL 33199, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 21, pp. 4507-4522
LA: English
ER: F (Freshwater)
AB: Water samples from rivers in the Orinoco Basin were examined in order to assess the biogeochemistry of particle-associated and dissolved lipids. Lipid fractions were characterised so as to determine their origin, speciation, variability in individual rivers, and their flux to the lower Orinoco River. Aliphatic hydrocarbons, ketones, alcohols, triterpenoids, and fatty acids were ubiquitous in the rivers, and a large proportion of these compounds were found to be autochthonous in origin. The relative loadings of particle-associated and dissolved lipids were of the same order of magnitude in most of the rivers, indicating the importance of the dissolved phase. Apparently, true equilibria between water and particulate phases were not reached, probably as a result of the high amounts of colloidal and humic materials associated with the dissolved phase in most of the rivers. Preliminary data indicate that there were considerable seasonal variabilities in the distributions and concentrations of lipids in some of the rivers, but that each of these showed different behaviour.
AN: 3931547
44 of 1521
TI: The role of phytoplankton cells on the control of heavy metal concentration in seawater
AU: Gonzalez-Davila,-M.
AF: Dep. Quimica, Fac. Cienc. del Mar, Univ. Palmas de Gran Canaria, 35017 Palmas de Gran Canaria, Spain
SO: MAR.-CHEM. 1995 vol. 48, no. 3-4, pp. 215-236
LA: English
ER: M (Marine)
AB: An overview is presented of the ability of phytoplankton to passively adsorb and actively assimilate heavy metals from their aqueous environment and to release into the environment organic ligands capable of complexing metals. The uptake of all necessary trace metals by phytoplankton occurs via binding to a surface ligand and subsequent transfer across the cell membrane. This sorptive process can be explained by using surface complex formation equilibria; due to the heterogeneity of the algal surface, multi-site binding models must be developed. The production of extracellular organic matter with metal complexing properties plays an important role in decreasing the concentration of free metal ions and thus mitigating the potential toxic effects on organisms. However, while much research has been carried out on the uptake of single species of metal ions, little attention seems to have been given to the study of multimetal ion systems. Synergistic and antagonistic interactions between multiple trace metals are expected and could be very important in the oceans. These types of behaviours are extremely complex, influencing uptake and release of natural ligands and limiting plankton production and plankton species composition in the oceans. Future investigations should be carried out in order to gain understanding how the combinations of metal ions affect the physiological, biochemical and ecological processes of phytoplankton in seawater.
AN: 3931544
45 of 1521
TI: Processes controlling the chemistry of two snowmelt-dominated streams in the Rocky Mountains
AU: Campbell,-D.H.; Clow,-D.W.; Ingersoll,-G.P.; Mast,-M.A.; Spahr,-N.E.; Turk,-J.T.
AF: U.S. Geological Surv., Lakewood, CO, USA
SO: WATER-RESOUR.-RES. 1995 vol. 31, no. 11, pp. 2811-2821
LA: English
ER: F (Freshwater)
AN: 3930730
46 of 1521
TI: Biogeochemical influences on the determination of water chemistry in a temperate forest basin: Factors determining the pH value
AU: Ohte,-N.; Tokuchi,-N.; Suzuki,-M.
AF: Dep. Forest., Fac. Agric., Kyoto Univ., Kyoto, Japan
SO: WATER-RESOUR.-RES. 1995 vol. 31, no. 11, pp. 2823-2834
LA: English
ER: F (Freshwater)
AN: 3930729
47 of 1521
TI: Part 2. Nutrients, particulate organic matter, and planktonic and benthic production of the Tikehau Atoll (Tuamotu Archipelago, French Polynesia)
AU: Charpy-Roubaud,-C.J.; Charpy,-L.
AF: ORSTOM-Tahiti, BP 529, Papeete, French Polynesia
SO: ATOLL-RES.-BULL. 1994 v.p.
LA: English
ER: M (Marine)
AB: Matter and energy budgets for coral reefs, their components, and the world around them can, do, and must balance in a theorical context (Smith and Kinsey, 1988). In this paper, we will try to establish nitrogen, phosphorus and silica budgets between ocean and lagoon waters of Tikehau atoll in the purpose to learn more about the functioning of coral reef lagoons. Nutrient concentrations (dissolved components and particulate organic matter) were measured in the lagoon and in the surrounding oceanic surface waters between 1983 and 1987.
AN: 3930690
48 of 1521
TI: Sulphur and nitrogen compounds in variable marine/continental air masses at the southwest European coast
AU: Pio,-C.A.; Cerqueira,-M.A.; Castro,-L.M.; Salgueiro,-M.L.
AF: Departamento de Ambiente e Ordenamento, Universidade de Aveiro, 3810 Aveiro, Portugal
SO: ATMOS.-ENVIRON. 1996 vol. 30, no. 18, pp. 3115-3127
LA: English
AB: Measurements of atmospheric sulphur and nitrogen species were made on the west coast of Portugal, within the framework of BMCAPE project. Four research intensive campaigns took place between November 1993 and August 1994 and revealed pronounced seasonal cycles for DMS and MSA. Surprisingly high levels of DMS were detected during autumn (mean concentration: 776 ng S m super(-3)), possibly as a consequence of a later algae bloom or local marsh emissions. COS displayed a slight seasonal variation with mean concentrations ranging from 741 ng S m super(-3) in autumn up to 903 ng S m super(-3) in summer. On the basis of backward air mass trajectories and local meteorological data, samples were assigned into different classes of air masses. The lowest concentrations of SO sub(2), nssSO sub(4) super(2-), NH sub(3), NH sub(4) super(+), HNO sub(3), NO sub(3) super(-) and NO sub(2) were found in air masses transported over the Atlantic Ocean and were about 3-10 times lower than those recorded in air masses from continental origin. Nevertheless, for many of the species, the mean concentrations in maritime air were still significantly higher than those previously recorded in remote marine sites, presumably owing to long-range transport of pollutants or contamination induced by mesoscale wind circulation.
AN: 3930604
49 of 1521
TI: Horizontal and vertical profiles of light hydrocarbons in sea water related to biological, chemical and physical parameters
AU: Ratte,-M.; Plass-Duelmer,-C.; Koppmann,-R.; Rudolph,-J.
AF: Institut Atmosphaerische Chemie, Forschungszentrum Juelich, 52425 Juelich, FRG
SO: TELLUS-B-CHEM.-PHYS.-METEOROL. 1995 vol. 47B, no. 5, pp. 607-623
LA: English
ER: M (Marine)
AB: In situ-measurements of light (C sub(2)-C sub(4)) nonmethane hydrocarbons (NMHC) in sea water were performed during a ship cruise in spring 1991 in the Mediterranean, the Atlantic and the North Sea. The investigated regions were characterized with respect to biological (phytoplankton density, chlorophyll concentration), chemical (concentration of dissolved organic carbon, DOC) and physical parameters (irradiation intensity, wind velocities). These data were analysed for possible correlations with NMHC concentrations. An anticorrelation was found between NMHC concentrations and wind velocity. During periods of very low wind velocities, i.e., low mixing in the ocean surface layer and low emission rates, the concentrations of alkenes in surface water exhibited a distinct diurnal pattern with the concentrations increasing during day time and remaining constant at night.
AN: 3927296
50 of 1521
TI: Oxygen isotope analyses of chemically and microbially produced manganese oxides and manganates
AU: Mandernack,-K.W.; Fogel,-M.L.; Tebo,-B.M.; Usui,-A.
AF: Earth System Sci., Phys. Sci. Res. Facility, Univ. California, Irvine, CA 92717-3100, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 21, pp. 4409-4425
LA: English
ER: M (Marine)
AB: Understanding the formation of metal deposition in the geological record depends in part on understanding some of the basic reactions that could have occurred when those ore deposits were formed. For manganese oxides and manganates, the delta super(18)O value might reflect the conditions that influenced the oxidation pathway during deposition, which include temperature, the delta super(18)O values of H sub(2)O or dissolved O sub(2), and microbial catalysis. Mn(IV) 10 angstrom manganates were, therefore, prepared by three different procedures with different sources of water having distinct delta super(18)O-H sub(2)O values, while keeping the delta super(18)O-O sub(2) constant. Application of the results to natural deposits of manganese oxides indicates a microbial origin for a freshwater manganese nodule from Oneida Lake, NY, USA, as well as a 50% dissolved oxygen signal. Oxygen isotopic values of Mn(IV) manganates from the Kaikata seamount, however, appear to reflect the delta super(18)O value of seawater exclusively. Therefore, Mn(IV) manganates in nature may not always contain a dissolved oxygen signal, presumably a result of different oxidation pathways or postdepositional alteration.
AN: 3927277
51 of 1521
TI: Manganese mineral formation by bacterial spores of the marine Bacillus, strain SG-1: Evidence for the direct oxidation of Mn (II) to Mn (IV)
AU: Mandernack,-K.W.; Post,-J.; Tebo,-B.M.
AF: Earth System Sci., Phys. Sci. Res. Facility, Univ. California, Irvine, CA 92717-3100, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 21, pp. 4393-4408
LA: English
ER: M (Marine)
AB: The spores of a marine Bacillus bacterium, strain SG-1, are able to oxidize Mn (II) over a wide range of temperatures (0-80 degree C) and Mn (II) concentrations (<1 nM to >25 mM), in both low ionic strength N-(2-hydroxyethyl) piperazine-N'-ethanesulfonic acid (HEPES) buffer (HB) and in HEPES-buffered seawater (SW). The observed differences between SW and HB may have resulted from differences in the chemical milieu, or because of the marine adapted physiology of the bacterial spores. Under a variety of conditions (HB and SW, 3-55 degree C) Mn(IV) mineral formation often occurred at pH and Mn(II) concentrations too high to be favorable for the disproportionation of Mn sub(3)O sub(4), or beta MnOOH to Mn (IV). The results strongly suggest direct oxidation of Mn(II) to Mn(IV) by SG-1 spores without lower valence intermediates. Considering the environmental relevance of these experiments, direct oxidation of Mn(II) to Mn(IV) by microbes is probably a common process in natural environments.
AN: 3927276
52 of 1521
TI: Seasonal cycles of pelagic production and consumption
AU: Longhurst,-A.
AF: Place de l'Eglise, 46160 Cajarc, France
SO: PROG.-OCEANOGR. 1995 vol. 36, no. 2, pp. 77-167
LA: English
ER: M (Marine)
AB: Comprehensive seasonal cycles of production and consumption in the pelagial require the ocean to be partitioned. This can be done rationally at two levels: into four primary ecological domains (three oceanic and one coastal), or about fifty biogeochemical provinces. The domains differ in their characteristic seasonal cycles of stability, nutrient supply and illumination, while provinces are defined by ocean currents, fronts, topography and recurrent features in the sea surface chlorophyll field. For each of these compartments, seasonal cycles of photic depth, primary production and accumulation (or loss) of algal biomass were obtained from the climatological CZCS chlorophyll field and other data and these, together with mixed layer depths, rendered characteristic seasonal cycles of production and consumption, which can be grouped into eight models: i - polar irradiance-mediated production peak; ii - nutrient-limited spring production peak; iii - winter-spring production with nutrient limitation; iv - small amplitude response to trade wind seasonality; v - large amplitude response to monsoon reversal; vi - canonical spring-fall blooms of mid-latitude continental shelves; vii - topography-forced summer production; viii - intermittent production at coastal divergences. For higher latitudes, these models suggest that the observed late-summer 'blooms' result not from a renewal of primary production rate, but from a relaxation of grazing pressure; in mid-latitudes, the observed 'winter' bloom represents chlorophyll accumulation at a season when loss terms are apparently smaller than during the period of peak primary production rate which occurs later, in spring. Where an episodic seasonal increase in rate of primary production occurs, as in the Arabian Sea, algal biomass accumulation may brief, lasting only until consumption is fully re-established. Only in the low latitude oligotrophic ocean are production and consumption perennially and closely coupled.
AN: 3926609
53 of 1521
TI: Carbon cycling in mesohaline Chesapeake Bay sediments 2: Kinetics of particulate and dissolved organic carbon turnover
AU: Roden,-E.E.; Tuttle,-J.H.
AF: Univ. Alabama, Dep. Biol. Sci., Box 870206, Tuscaloosa, AL 35487-0206, USA
SO: J.-MAR.-RES. 1996 vol. 54, no. 2, pp. 343-383
LA: English
ER: B (Brackish)
AB: Temporal and depth variations in benthic carbon metabolism rates were examined in relation to particulate organic carbon (POC) deposition rates and particulate and dissolved organic carbon degradation kinetics in two sediments from the mesohaline region of Chesapeake Bay. The depth distribution of a single pool of metabolizable POC (MPOC) in mid-Bay sediments was estimated by curve-fitting of dry weight POC profiles ("I-G" approach). Estimated MPOC pools accounted for 3-4% of total POC content in the upper 10 cm of sediment. First-order MPOC decay constants of approximately 10 yr super(-1) during the warm season were estimated from the ratio of MPOC pool size to weighted-average MPOC deposition rate derived from mid-water column sediment trap deployments. These results indicated that the MPOC pool defined by the 1-G approach corresponded to the most readily degradable component of coastal marine phytoplankton detritus. Transient-state kinetic models of MPOC turnover, based on observed MPOC deposition rates and temperature-dependent mineralization, predicted MPOC accumulation in sediments during the spring followed by depletion during the summer. The models also predicted an early summer maximum in MPOC mineralization rate associated with the degradation of MPOC accumulated during the spring, in agreement with the seasonal pattern of sulfate reduction rates in mid-Bay sediments. Model results suggested that MPOC deposition during the summer is important in maintaining high rates of benthic carbon metabolism throughout the warm season.
AN: 3926606
54 of 1521
TI: Effects of eucalyptus afforestation on leaf litter dynamics and macroinvertebrate community structure of streams in Central Portugal
AU: Abelho,-M.; Graca,-M.A.S.
AF: Dep. Zoologia, Univ. Coimbra, 3049 Coimbra Codex, Portugal
SO: HYDROBIOLOGIA 1996 vol. 324, no. 3, pp. 195-204
LA: English
ER: F (Freshwater)
AB: To test the hypothesis whether afforestation with Eucalyptus globulus affects litter dynamics in streams and the structure of macroinvertebrate aquatic communities, we compared streams flowing through eucalyptus and deciduous forests, paying attention to: (i) litterfall dynamics, (ii) accumulation of organic matter, (iii) processing rates of two dominant leaf species: eucalyptus and chestnut, and (iv) macroinvertebrate community structure. The amount of allochthonous inputs was similar in both vegetation types, but the seasonality of litter inputs differed between eucalyptus and natural deciduous forests. Eucalyptus forest streams accumulated more organic matter than deciduous forest streams. Decomposition of both eucalyptus and chestnut leaf litter was higher in streams flowing through deciduous forests. The eucalyptus forest soils were highly hydrophobic resulting in strong seasonal fluctuations in discharge. In autumn the communities of benthic macroinvertebrates of the two stream types were significantly different. Deciduous forest streams contained higher numbers of invertebrates and more taxa than eucalyptus forest streams. Mixed forest streams (streams flowing through eucalyptus forests but bordered by deciduous vegetation) were intermediate between the two other vegetation types in all studied characteristics (accumulation of benthic organic matter, density and diversity of aquatic invertebrates). These results suggest that monocultures of eucalyptus affect low order stream communities. However, the impact may be attenuated if riparian corridors of original vegetation are kept in plantation forestry.
AN: 3926530
55 of 1521
TI: Effects of drying-out on the biogeochemical cycle of nitrogenous nutrients in oyster ponds: Preferential ammonification
OT: Effets de l'assechement des bassins ostreicoles sur le cycle biogeochimique de nutrienets azotes: Ammonification preferentielle
AU: Gouleau,-D.; Feuillet-Girard,-M.; Germaneau,-J.; Robert,-S.
AF: CNRS-IFREMER, Centre de Recherche en Ecologie Marine et Aquaculture de L'Houmeau, BP 5, 17137 L'Houmeau, France
SO: OCEANOL.-ACTA 1996 vol. 19, no. 2, pp. 101-115
LA: French
ER: M (Marine)
AB: Oyster ponds behave as organic matter accumulators, unlike wetlands which export a large part of their natural productivity towards the ocean as well as inorganic nitrogen towards the atmosphere through denitrification. Thus, to prevent eutrophication temporary drying-out is necessary, the physical effects of which are well known but whose biogeochemical processes are still poorly documented. The aim of the present study was to perform a drying-out operation in an oyster pond, and to describe the modifications which occurred within the nitrogen cycle: i. e. mineralization processes within the top 5 cm of the sediment; changes in nutrient pore-water concentrations; and fluxes through the water/sediment interface. Prior to the operation, ammonia was the major nitrogen form in the water column and in pore waters (top 5 cm); concentrations of free NH sub(4) super(+) increased as a function of depth, whereas exchangeable NH sub(4) super(+) decreased. At the end of drying-out, when salt precipitation first occurred at the water/sediment interface, the sediment remained reduced despite a slight oxidation around des s icati on cracks, thus preventing nitrification. In consequence, ammonification was the prevailing process within the sediment. At the surface of the sediment, concentrations of free NH sub(4) super(+) in pore waters were 45 times as high as at the beginning of the drying-out, whereas they remained constant at 5 cm depth; exchangeable NH sub(4) super(+) did not increase accordingly, but tended, rather, to decrease. Strong increases of free ammonia were correlated to those of pore-water salinity. The non-adsorption of NH sub(4) super(+) on sediment and the concomitant defixing of NH sub(4) super(+) from illitic clays were due to increasing quantities of K super(+), as a consequence of the high salinities induced by drying. The flooding carried out a few days after the occurrence of salt precipitation had the following effects: (i) maximum ammonia fluxes through the water/sediment interface which persisted for a long time after flooding; (ii) restoration of reduced conditions which prevented nitrogen loss due to the coupling of nitrification and denitrification; (iii) disappearance of high salinities in pore waters, thus eliminating the effect of K super(+) on clays, and allowing NH sub(4) super(+) fixing and adsorption on sediments. In conclusion, drying-out might help physically to control ammonia production, independently of the biological production (bacterial mineralization) which is controlled bv temperature.
AN: 3921797
56 of 1521
TI: Is DOC the main source of organic matter remineralization in the ocean water column?
AU: Lefevre,-D.; Denis,-M.*; Lambert,-C.E.; Miquel,-J.-C.
AF: Cent. d'Oceanologie de Marseille, CNRS URA 041, Universite d'Aix-Marseille II, Parc Scientifique et Technologique de Luminy, Case 901, 13288 Marseille Cedex 09, France
CO: 1994 International Liege Colloquium on Ocean Hydrodynamics, Liege (Belgium), 2-6 May 1994
SO: THE-COASTAL-OCEAN-IN-A-GLOBAL-CHANGE-PERSPECTIVE. Djenidi,-S.-ed. 1996 vol. 7, no. 2-4 pp. 281-291
ST: J.-MAR.-SYST. vol. 7, no. 2-4
LA: English
ER: M (Marine)
AB: Recent interpretations of carbon flux data and deep-sea processes have led to a reconsideration of the role of dissolved organic carbon (DOC) in supporting water column remineralization and other mid-water biogeochemical transformations. To date, there have been no direct comparisons of particulate carbon flux data with water column metabolic rates. Here, for the first time, particulate carbon flux and respiratory electron transport activity (from which metabolic CO sub(2) production is derived), have been monitored simultaneously for one year in the same area of the northwestern Mediterranean Sea. In the aphotic layer (200-1000 m), particulate organic carbon (POC) can support only 20% of the overall organic matter remineralization. Remineralization rates are consistent with recent calculations of DOC exported from the euphotic layer in this area, confirming the vital importance of DOC in maintaining deep-water metabolism. This finding would apply to other regions of mesotrophic and oligotrophic production and thus affect our understanding of carbon recycling in the water column, new production and O sub(2) utilization.
AN: 3920080
57 of 1521
TI: Spatial and temporal variability of phytoplankton biomass in upwelling areas of the northwestern Mediterranean: A coupled physical and biogeochemical modelling approach
AU: Pinazo,-C.; Marsaleix,-P.; Millet,-B.; Estournel,-C.; Vehil,-R.
AF: Cent. Oceanol. Marseille, URA CNRS 41, Univ. Aix-Marseille II, Campus Luminy, F-13288 Marseille Cedex 09, France
CO: 1994 International Liege Colloquium on Ocean Hydrodynamics, Liege (Belgium), 2-6 May 1994
SO: THE-COASTAL-OCEAN-IN-A-GLOBAL-CHANGE-PERSPECTIVE. Djenidi,-S.-ed. 1996 vol. 7, no. 2-4 pp. 161-191
ST: J.-MAR.-SYST. vol. 7, no. 2-4
LA: English
ER: M (Marine)
AB: The coupling of a 3-D hydrodynamic model and the biogeochemical algorithms of phytoplankton biomass production was performed at the meso scale of the northwestern Mediterranean shelf. This study, which was part of the French Programme National d'Oceanographie Cotiere, represented a theoretical approach to study the phytoplankton dynamics at mesoscale, according to upwelling processes induced by both the general circulation (LPC) and the typical northwestern wind that prevail in the Gulf of Lions. The coupling task consisted in writing the equations of nitrogen and carbon cycles form both the algorithms describing the biogeochemical gain and loss terms, and the advective-diffusive numerical scheme of the physical model, according to the same spatial grid. This approach allowed fine 3-D spatial descriptions of the biogeochemical processes during 20-day periods. The physical parameters used in the advective-diffusive numerical scheme, such as velocities and coefficients of vertical eddy diffusivity, were first calculated by the hydrodynamic model, averaged over one inertial period (17.6 h), and then introduced into the biogeochemical coupled model as constant forcing variables.
AN: 3920077
58 of 1521
TI: Chemical fractionation of phosphorus and cadmium in the marine diatom Phaeodactylum tricornutum
AU: Kudo,-Isao; Kokubun,-Haruyo; Matsunaga,-Katsuhiko
AF: Department of Oceanography, Faculty of Fisheries, Hokkaido University, Hakodate 041, Japan
SO: MAR.-CHEM. 1996 vol. 52, no. 3-4, pp. 221-231
LA: English
AB: Fractionation of P and Cd within the cell of Phaeodactylum tricornutum grown by semi-continuous cultures in natural low concentrations of dissolved phosphate and cadmium was examined by the chemical separation method. Cellular Cd content increased with the concentration of Cd in the medium and was independent of growth rate, but it was present only in the acid-soluble fraction and no growth inhibition was observed even at 90 nM. Cellular P content in the acid-soluble fraction varied with both growth rate and concentration in the medium. The residue fraction (acid-insoluble) depended on concentration in the medium. Proportion of these fractions, however, changed only as a function of growth rate. As a consequence of these changes, cellular Cd/P ratio decreased with growth rate. The distributions of Cd and P in the phytoplankton cells were not always the same portion. The Cd/P ratio in phytoplankton cells is affected by the physiological state of the cells and ambient Cd/PO4 ratio in the medium. Thus, biological activity would influence the biogeochemical cycling of Cd and PO4 and the Cd/PO4 ratio in the ocean.
AN: 3915447
59 of 1521
TI: Trends in eutrophication research and control
AU: Rast,-W.; Thornton,-J.A.
AF: Freshwater Programme, United Nations Environ. Programme, PO Box 30552, Nairobi, Kenya
SO: HYDROL.-PROCESS. 1996 vol. 10, no. 2, pp. 295-313
LA: English
ER: F (Freshwater)
AB: Eutrophication is the natural process of lakes. It is characterized by a geologically slow shift from in-lake biological production driven by allochthonous (external to the water body) loading of nutrients, to production driven by autochthonous (in-lake) processes. This shift typically is accompanied by changes in species and biotic community composition, as an aquatic ecosystem is ultimately transformed into a terrestrial biome. However, this typically slow process can be greatly accelerated by human intervention in the natural biogeochemical cycling of nutrients within a watershed; the resulting cultural eutrophication can create conditions inimical to the continued use of the water body for human-driven economic purposes. Excessive algal and rooted plant growth, degraded water quality, extensive deoxygenation of the bottom water layers and increased fish biomass accompanied by decreased harvest quality, are some features of this process.
AN: 3914315
60 of 1521
TI: The sulfur cycle in the chemocline of a meromictic salt lake
AU: Overmann,-J.; Beatty,-J.T.; Krouse,-H.R.; Hall,-K.J.
AF: Inst. fuer Chemie und Biologie des Meeres, Univ. Oldenburg, Postfach 2503, D-26111 Oldenburg, Germany
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 1, pp. 147-156
LA: English
ER: F (Freshwater)
AB: An extremely dense layer of the purple sulfur bacterium Amoebobacter purpureus in the chemocline of meromictic Mahoney Lake (British Columbia) was investigated over a 2-yr period. Within this layer, sulfide, elemental sulfur, and polysulfides were the main species of reduced sulfur. The oxidative part of the sulfur cycle was dominated by anoxygenic photosynthesis of A. purpureus. During summer, when sulfide concentrations in the layer were limiting, intracellular sulfur became the main electron donor for photosynthesis. delta super(34)S determinations revealed that the intracellular sulfur reacts chemically with dissolved sulfide to form polysulfides. Polysulfide concentrations decreased over summer, accompanied by an increase in numbers of sulfur-reducing bacteria. Sulfate reduction was the major pathway of sulfide formation. The annual carbon requirement of sulfate-reducing bacteria in the chemocline (22.5 g C m super(-2) yr super(-1)) was met by the photosynthetic C fixation of A. purpureus (33.5 g C m super(-2) yr super(-1)). Carbon demand exceeded the concomitant C fixation temporarily in summer, however. The activities of biomass-degrading enzymes and the formation of volatile fatty acids were sufficient to provide the carbon substrates. Our data indicate that in Mahoney Lake, anoxygenic photosynthesis and sulfate reduction are only indirectly coupled via degradation and autolysis of photosynthetically formed biomass.
AN: 3913682
61 of 1521
TI: Marine scavenging: The relative importance of mass transfer and reaction rates
AU: Jannasch,-H.W.; Honeyman,-B.D.; Murray,-J.W.
AF: Monterey Bay Aquarium Res. Inst., POB 628, 7700 Sandholdt Rd., Moss Landing, CA 95039, USA
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 1, pp. 82-88
LA: English
ER: M (Marine)
AB: We present an analysis of factors regulating the scavenging rate of trace elements and nutrients by settling particles in the ocean. The overall process limiting marine scavenging rates is determined by comparing the relative kinetics of dissolved phase mass transfer and particle-associated sorption rates. Measured scavenging and uptake rates of a variety of marine particle types are then compared to theoretically calculated mass transfer rate constants. Our calculations show that for most marine environments, sorption rates are much slower than external mass transfer of dissolved species. External mass transfer is therefore not the limiting process. Particle-associated processes such as adsorption, intraparticle reactions, and particle repackaging must control the overall scavenging rates observed in the ocean.
AN: 3913679
62 of 1521
TI: Microbial cycling of DMSP and DMS in coastal and oligotrophic seawater
AU: Ledyard,-K.M.; Dacey,-J.W.H.
AF: Mar. Sci. Inst., Univ. California, Santa Barbara, CA 93106, USA
SO: LIMNOL.-OCEANOGR. 1996 vol. 41, no. 1, pp. 33-40
LA: English
ER: M (Marine)
AB: The rates and concentration dependence of microbial dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) cycling were assessed in Vineyard Sound, Massachusetts, and the Sargasso Sea. Net rates of dissolved DMSP loss, DMS production from DMSP, and DMS consumption were measured at ambient and near-ambient substrate levels. Turnover times of dissolved DMSP, based on loss rates, were short, usually ranging from 1.5 d to several hours. However, the specific process of DMSP cleavage to form DMS accounted for only a portion of total DMSP turnover. Short-term variability obscured possible regional or seasonal trends in these data. Dissolved DMSP removal and cleavage exhibited saturable kinetics in spring in Vineyard Sound and in winter in the Sargasso Sea. In fall and spring in the Sargasso Sea, where dissolved DMSP levels ranged from 2 to 9 nM, DMSP cleavage did not saturate at DMSP levels as high as 1 mu M. Kinetic parameters of DMSP uptake appeared to increase with proximity to summer, as did the proportion of DMSP uptake resulting in DMS production.
AN: 3913674
63 of 1521
TI: A preliminary study on the bioactivity of dissolved organic phosphorus in marine environment
AU: Wang,-Haili; Hong,-Huasheng; Huang,-Bangqin
AF: Res. Cent. Environ. Sci., Xiamen Univ., Xiamen 361005, People's Rep. China
SO: J.-XIAMEN-UNIV.-NAT.-SCI.-XIAMEN-DAXUE-XUEBAO 1995 vol. 34, no. 3, pp. 416-420
LA: Chinese
ER: M (Marine)
AB: Results from batch culture experiments indicated that adenosine triphosphate, sodium glycerophosphate (GP) and ribose-5-phosphate could be utilized by phytoplankton. The availability of dissolved organic phosphorus (DOP) was comparable to that of dissolved inorganic phosphorus (DIP). It seemed that although algae preferred DIP when DIP and DOP co-existed, DOP could also be uptaken right after the depletation of DIP. The uptake of DOP was relatively quicker under lower ambient concentration, implicating its potential environmental effects.
AN: 3911549
64 of 1521
TI: Aerobic and anaerobic decomposition of organic matter in marine sediment: Which is fastest?
AU: Kristensen,-E.; Ahmed,-S.I.; Devol,-A.H.
AF: Inst. Biol., Odense Univ., DK-5230 Odense M, Denmark
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 8, pp. 1430-1437
LA: English
ER: M (Marine)
AB: The enigma of aerobic vs. anaerobic decomposition in marine sediments was addressed by means of a thin-layer incubation technique. Two different super(14)C-labeled plant materials, aged diatoms (Skeletonema costatum) and fresh barley hay, were each mixed into intertidal sediment and spread in a 1.5-mm layer on the bottom of oxic and anoxic chambers. After a 27-d incubation, conditions in all chambers were switched from aerobic to anaerobic and vice versa for 11 d. Rates of super(14)CO sub(2) evolution in diatom chambers showed that aerobic carbon mineralization was similar to 10 times faster than anaerobic both before and after the switch. Low rates of [ super(14)C]DOC release suggested that the limiting step of anaerobic decay was the initial hydrolytic and fermentative enzymatic attack on the predecomposed diatoms. Initial carbon mineralization of barley hay was not affected by the presence or absence of oxygen. Leaching of DOC from the fresh barley hay supplied anaerobic respirers with labile substrates. When leaching ceased and after the aerobic-anaerobic switch, the rate of anaerobic mineralization was reduced. Mineralization of leachable and easily hydrolyzable compounds from fresh plant detritus is equally fast under aerobic and anaerobic conditions. When structural components dominate the particulate remains, anaerobic processes are hampered by inefficient and slow bacterial hydrolysis of structurally complex macromolecules.
AN: 3907920
65 of 1521
TI: Redox stabilization of the atmosphere and oceans by phosphorus-limited marine productivity
AU: van-Cappellen,-P.; Ingall,-E.D.
AF: Sch. Earth and Atmos. Sci., Georgia Inst. Technol., Atlanta, GA 30332-0340, USA
SO: SCIENCE-WASH. 1996 vol. 271, no. 5248, pp. 493-496
LA: English
ER: M (Marine)
AB: Data from modern and ancient marine sediments demonstrate that burial of the limiting nutrient phosphorus is less efficient when bottom waters are low in oxygen. Mass-balance calculations using a coupled model of the biogeochemical cycles of carbon, phosphorus, oxygen, and iron indicate that the redox dependence of phosphorus burial in the oceans provides a powerful forcing mechanism for balancing production and consumption of atmospheric oxygen over geologic time. The oxygen-phosphorus coupling further guards against runaway ocean anoxia. Phosphorus-mediated redox stabilization of the atmosphere and oceans may have been crucial to the radiation of higher life forms during the Phanerozoic.
AN: 3907143
66 of 1521
TI: Variability in removal of dissolved organic carbon in hyporheic sediments
AU: Findlay,-S.; Sobczak,-W.V.
AF: Inst. Ecosystem Stud., PO Box AB, Millbrook, NY 12545, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1996 vol. 15, no. 1, pp. 35-41
LA: English
ER: F (Freshwater)
AB: Dissolved organic carbon (DOC) is consumed by microbial metabolism as streamwater perfuses through a lateral gravel bar of the East Branch of the Wappinger Creek. The rate of DOC removal was estimated from the decline in DOC and travel time through the bar. Variability in DOC removal together with potential regulatory factors was determined for 14 dates spanning more than a 2-y period. DOC removal was not correlated with temperature, availability of oxygen, or residence time within hyporheic sediments. Hyporheic DOC could be predicted (r super(2) = 0.68) from streamwater DOC concentrations, with a surprisingly constant 57% ( plus or minus 9% [1 SD]) removal of DOC. This pattern suggests an initial concentration-dependent adsorption of DOC onto surfaces. This mechanism allows for efficient retention of DOC within hyporheic sediments even under conditions (low temperature, high interstitial velocity) that might be expected to minimize biotic consumption of DOC.
AN: 3906298
67 of 1521
TI: Seasonal and storm dynamics of the hyporheic zone of a 4th-order mountain stream. 2: Nitrogen cycling
AU: Wondzell,-S.M.; Swanson,-F.J.
AF: Dep. Forest Sci., Oregon State Univ., Corvallis, OR 97331, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1996 vol. 15, no. 1, pp. 20-34
LA: English
ER: F (Freshwater)
AB: The objective of this study was to quantify subsurface nitrogen fluxes between a riparian forest and a 4th-order mountain stream, McRae Creek, for each season of the year and during storms. A network of wells was installed on a gravel bar and a portion of the adjacent floodplain between 1989 and 1992. Water samples were collected to monitor dissolved nitrogen concentrations. Advected channel water and ground water were enriched in nitrogen relative to the stream; thus, subsurface flow was a net source of nitrogen to the stream in all seasons of the year and during both base-flow periods and storms. Estimates of the flux of advected channel water and the discharge of ground water were combined with changes in mean nitrogen concentrations along subsurface flow paths to estimate nitrogen inputs to the stream. Discharge or ground water from the conifer-dominated floodplain was the largest source of nitrogen added to the stream; however, more than 50% of this nitrogen was dissolved organic nitrogen. In contrast, two-thirds of the nitrogen from the alder-dominated gravel bar was inorganic. Net nitrogen fluxes from the gravel bar to the stream were lowest during the summer when water table elevations were low. Net fluxes of nitrogen from the gravel bar to the stream were largest during the fall, especially at peak flow during storms when interstitial water in the gravel bar was enriched in NO sub(3) super(-). The estimated annual flux of nitrogen from the riparian forest to McRae Creek was 1.9 g/m super(2) of streambed, of which 1.0 g/m super(2) was inorganic. Estimated net annual flux was large relative to the estimated input of nitrogen in litterfall, or the nitrogen required to support estimated rates of primary productivity.
AN: 3906297
68 of 1521
TI: Patterns of differential digestion of sedimentary bacteria by the deposit feeder, Arenicola marina
AU: Goldfinch,-A.; Plante,-C.
AF: Dep. Biol., Univ. Charleston, Charleston, SC 29412, USA
CO: 24. Annu. Benthic Ecology Meeting, Columbia, SC (USA), 7-10 Mar 1996
SO: TWENTY-FOURTH-ANNUAL-BENTHIC-ECOLOGY-MEETING,-HELD-IN-COLUMBIA,-SOUTH-CAROLINA,-MARCH-7-10,-1996. Woodin,-S.A.;Allen,-D.M.;Stancyk,-S.E.;Williams-Howze,-J.;Feller,-R.J.;Wethey,-D.S.;Pentcheff,-N.D.;Chandler,-G.T.;Decho,-A.W.;Coull,-B.C.-eds. 1996 p. 42
NT: Abstract only
LA: English
ER: M (Marine)
AB: Sedimentary bacteria are consumed and digested by deposit-feeding macrofauna. This predator-prey relationship may markedly influence biogeochemical cycling and food web dynamics. Bacterial community compositions, for instance, may be altered by selective digestion of diverse strains, thus influencing rates of geochemical reactions. We used a turbidimetric assay to compare the lytic susceptibilities of bacteria when exposed to the digestive fluids collected from the deposit-feeding polychaete, Arenicola marina. Over two dozen environmental isolates were tested under identical conditions. Significantly different bacteriolytic rates were observed; 75% of strains were completely resistant to lysis, while the remaining strains exhibited varied rates of digestion. Potentially important differences among these strains, such as cell wall type (gram-positive v. gram-negative), and exopolymer secretions, were examined in an effort to identify mechanisms for differential digestion.
AN: 3904787
69 of 1521
TI: Regeneration of trace metals from picoplankton by nanoflagellate grazing
AU: Twiss,-M.R.; Campbell,-P.G.C.*
AF: INRS-Eau, Universite du Quebec, C.P. 7500, Ste-Foy, PQ G1V 4C7, Canada
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 8, pp. 1418-1429
LA: English
AB: Rapid regeneration of trace metals from the particulate to the dissolved phase (<0.2 mu m) was observed in the laboratory with a simplified microbial food web composed of mixotrophic chrysophycean nanoflagellates (Ochromonas danica) grazing on picocyanobacteria (Synechococcus leopoliensis) that had been previously exposed to the radionuclides super(153)Gd(III), super(65)Zn(II), super(109)Cd(II), and super(137)Cs(I). These trace metals were chosen to represent a range of surface reactivities with particles (Gd>Zn, Cd greater than or equal to Cs). Grazing experiments and the appropriate nongrazing controls were carried out in batch cultures over 43-49 h in defined, inorganic freshwater medium; metal partitioning among the consumer, prey, and dissolved phases was determined by sequential filtration (3 mu m, 0.2 mu m) at timed intervals. Most of the trace metals consumed as radioactive prey were regenerated into the dissolved phase. Regenerated Gd, Zn, and Cd present in the dissolved phase were less available for resorption by plankton than were the same radionuclides added in inorganic form to fresh growth medium. Our suggest that where this grazing activity exists, it will serve to increase trace metal residence times in the water column.
AN: 3902390
70 of 1521
TI: Spreading of water masses and regeneration of silica and super(226)Ra in the Indian Ocean
AU: Kumar,-M.D.; Li,-Y.-H.
AF: Natl. Inst. Oceanogr., Dona Paula, Goa 403 004, India
SO: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. 1996 vol. 43, no. 1, pp. 83-110
LA: English
ER: M (Marine)
AB: The magnitudes of silica and super(226)Ra inputs to water (through particle regeneration, in situ, and from sediments) and the validity of observed Si and super(226)Ra as tracers of water masses and advective processes were examined in the Indian Ocean using the GEOSECS data. The regenerated quantities of these two parameters were calculated as the difference between the observed and the expected concentrations; the latter were estimated from a three end-member mixing model employing potential temperature and salinity as conservative tracers. Here we present results on the quantitative spreading of the Antarctic Bottom Water (AABW); the Modified North Atlantic Deep Water (MNADW, also known as the Circumpolar Water) and the North Indian Deep Water (NIDW)-both these were represented together as High Salinity Deep Waters (HSDW); the Antarctic Intermediate Water (AAIW); the North Indian Intermediate Water (NIIW) and the Central Indian Water (CIW). Our results concur with recent results in the literature. Briefly, the northward flow of the AABW is uneven; the MNADW core layer is found to be closer to the Antarctic that spreads to the north, and AAIW is largely restricted to the Indian Ocean south of 10 degree S. Our results also reveal that: roughly 10% more AABW enters the Bay of Bengal than the Arabian Sea; there is greater possibility for deep waters to enter the Central Indian Basin from the Bay of Bengal; CIW occupies a larger part of the Bay of Bengal than of the Arabian Sea; and 10% of the NIIW reaches 30 degree S in the western Indian Ocean. The regenerations of Si and super(226)Ra are mainly from the underlying sediments rather than through the dissolution of particles in the water column. The sediments in the northern parts seem to supply super(226)Ra and Si to the rest of the Indian Ocean. At 10 degree S there is a subsurface ( similar to 600 m) maximum in regenerated Si, which is possibly connected to the advection of particles by Indonesian waters. The maxima in regenerated super(226)Ra and Si contribute about 50% and 30%, respectively, to the observed abundances, suggesting that the observed Si is a more useful tracer of water masses and mixing processes than super(226)Ra. Linear relationships were found between regenerated Si and super(226)Ra, but departures noticed for super(226)Ra in the eastern Indian Ocean may be attributed to its release from particles transported by the Indian rivers. Diverse regimes with respect to the extent of sources and dissolution of opal were noted in the Indian Ocean: high diatom abundance but low Si regeneration in the Antarctic, high diatom abundance and high regenerated Si in the Arabian Sea, and low diatom abundance but high regenerated Si in the Bay of Bengal.
AN: 3899160
71 of 1521
TI: Chemotaxis links the marine microbial loop to atmospheric sulfur production
AU: Zimmer-Faust,-R.; De-Souza,-M.; Yoch,-D.
AF: Dep. Biol. and Mar. Sci. Cent., Univ. California, Los Angeles, CA 90095-1606, USA
CO: 24. Annu. Benthic Ecology Meeting, Columbia, SC (USA), 7-10 Mar 1996
SO: TWENTY-FOURTH-ANNUAL-BENTHIC-ECOLOGY-MEETING,-HELD-IN-COLUMBIA,-SOUTH-CAROLINA,-MARCH-7-10,-1996. Woodin,-S.A.;Allen,-D.M.;Stancyk,-S.E.;Williams-Howze,-J.;Feller,-R.J.;Wethey,-D.S.;Pentcheff,-N.D.;Chandler,-G.T.;Decho,-A.W.;Coull,-B.C.-eds. 1996 p. 90
NT: Abstract only
LA: English
ER: M (Marine)
AB: Dimethylsulfide (DMS) gas comprises 90% of biogenic sulfur emissions from oceans and is an important agent in climate regulation. DMS arises primarily via lyase degradation of dimethylsulfoniopropionate (DMSP), an osmolyte produced in high concentrations by marine phytoplankton. DMSP lyase producing bacteria (Alcaligenes strain M3A) significantly reduce their tumbling frequency and are attracted to DMSP at levels found near senescing phytoplankton cells (10 super(-8) to 10 super(-6) M). In contrast, genetically identical bacteria without the induced lyase are not attracted to DMSP. Combined with lyase activity, microbial chemotaxis to DMSP should increase the rate of DMS production and, therefore, play a critical role in biogeochemical sulfur cycling between dissolved organic matter in seawater and earth's atmosphere.
AN: 3899005
72 of 1521
TI: Microbial production, enzyme activity, and carbon turnover in surface sediments of the Hudson River estuary
AU: Sinsabaugh,-R.L.; Findlay,-S.
AF: Biol. Dep., Univ. Toledo, Toledo, OH 43606, USA
SO: MICROB.-ECOL. 1995 vol. 30, no. 2, pp. 127-141
LA: English
ER: F (Freshwater)
AB: The authors investigated variability in microbial abundance and activities within the tidal freshwater estuary of the Hudson River. Surface sediments were collected from four contrasting sites: a mid-channel shoal, two types of wetlands, and a tributary confluence. These samples, collected in June to August 1992, were sorted into two to four size fractions, depending on the particle size distribution at each site. Each fraction was analyzed for bacterial biomass, bacterial production, fungal biomass, fungal production, and the potential activities of seven extracellular enzymes involved in degradation. Decomposition rates for particulate organic carbon (POC) were estimated from a statistical model relating mass loss rates to endocellulase activity. Within samples, bacterial biomass and productivity were negatively correlated with particle size. Conversely, fungal biomass was positively correlated with particle size. Extracellular enzyme activities also differed significantly among size classes, with high carbohydrase activities associated with the largest particles, while oxidative activities predominated in the smallest size classes.
AN: 3898779
73 of 1521
TI: Uptake of fenvalerate by the ostracod Chrissia halyi (Ferguson)
AU: Zeba,-M.; Khan,-M.A.; Rao,-B.N.
AF: H. No. 142-B Class, Mallapally, Hyderabad-500 007, India
SO: BULL.-ENVIRON.-CONTAM.-TOXICOL. 1996 vol. 56, no. 3, pp. 483-485
LA: English
ER: F (Freshwater)
AB: Once a pesticide is introduced into the environment there is a reasonable chance that it will eventually find its way into water. Therefore aquatic systems probably represent one of the most important complex environment as far as describing the fate and behaviour of pesticides. Zooplankton comprise a large portion of the living matter in natural waters and play an important role in biogeochemical cycles. Ostracods are one of the important zooplanktonic groups and constitute a significant percentage of the benthic fauna in a number of fresh water basins. The abundance of these organisms provide a very good food to the fish and other invertebrates. Being benthic in nature it is assumed that these ostracods can accumulate the toxicants at a higher level, at the same time being primary consumers they are assumed to be important organisms transferring the toxicants to higher trophic levels. In the present study an attempt has been made to see the accumulation of fenvalerate, a synthetic pyrethroid in the ostracod Chrissia halyi.
AN: 3898288
74 of 1521
TI: Seasonal biogeochemical patterns in surface water, subsurface hyporheic, and riparian ground water in a temperate stream ecosystem
AU: Hendricks,-S.P.; White,-D.S.
AF: Hancock Biological Station, Route 3, Box 288M, Murray, KY 42071, USA
SO: ARCH.-HYDROBIOL. 1995 vol. 134, no. 4, pp. 459-490
NT: Bibliogr.: 58 ref.
LA: English
ER: F (Freshwater)
AB: Relationships among stream surface water (9-km reach), substream hyporheic water ( 10-m pool-riffle-pool reach), and riparian groundwater (single site) biogeochemical patterns were examined in four seasons (1989-1990) in a temperate stream ecosystem (Michigan, USA). Surface water concentrations of chloride, dissolved organic carbon (DOC), and chlorophyll-a exceeded those of groundwater during most sampling periods. Groundwater and hyporheic concentrations of silica (SiO sub(2)), soluble reactive phosphorus (SRP), nitrate+nitrite (NO sub(3)-N), and ammonium (NH sub(4)-N) were generally higher than in surface water, particularly during summer. Hyporheic temperatures exhibited sharpest gradients with depth and distance downstream beneath a study riffle during summer and winter. Biologically reactive solutes (SRP, NO sub(3)-N, NH sub(4)-N, and DOC) generally decreased with depth and increased with distance beneath the riffle during summer and winter as well. Hyporheic patterns were indistinct or more variable during spring and fall and were attributed, in part, to the breakdown of thermal gradients within the bed, similar to seasonal lake turnover (mixis). Similarities between longitudinal/depth gradients in hyporheic patterns and longitudinal stream channel patterns for SiO sub(2) and Cl (the more conservative solutes) indicated potential cumulative groundwater discharge effects through successive hyporheic zones over stream distance. Relationships between hyporheic patterns, stream channel patterns, and the biologically reactive solutes (SRP, NO sub(3)-N, NH sub(4)-N, DOC) were less clear because of potential biotic or abiotic uptake at the sediment-water interface. Groundwater-surface water interaction within a hyporheic zone forms a complex system structured not only by hydrologic forces but also by seasonal changes in temperature and discharge.
AN: 3897613
75 of 1521
TI: Size-distribution analysis of sub-micron colloidal particles in river water
AU: Kim,-J.P.; Lemmon,-J.; Hunter,-K.A.*
AF: Dep. Chem., Univ. Otago, Dunedin, New Zealand
SO: ENVIRON.-TECHNOL. 1995 vol. 16, no. 9, pp. 861-868
LA: English
ER: F (Freshwater)
AB: The particle size spectra of sub-micron colloidal particles collected from a river water, the Water of Leith in Dunedin, New Zealand, have been determined by transmission electron microscopy (TEM). Particles were isolated onto hydrophilic carbon films by ultracentrifugation at 300,000 g for 1 hr. Size spectra were found to conform to a power-law size distribution dn/dr = A r super(- beta ), behaviour also found for much larger-sized particles in natural waters and marine colloids. Values of the exponent beta for unfiltered samples were in the range 2.3-2.9, consistent with Brownian aggregation as the principal mechanism maintaining the size spectrum. Comparison with spectra obtained from sampled prefiltered through Nuclepore 0.4 mu m filters showed clear evidence of particle removal down to 100-120 nm radius by filtration. Particles exhibited a range of electron densities under TEM, indicating a mixture of inorganic minerals and organic matter in the colloidal size range. Examples of fractal aggregates were also found.
AN: 3887090
76 of 1521
TI: Palmer LTER: Hydrogen peroxide in the Palmer LTER region: 3. Local sources and sinks
AU: Tien,-G.; Karl,-D.M.
AF: Sch. Ocean and Earth Sci. and Technol., Univ. Hawaii, Honolulu, HI 96822, USA
SO: ANTARCT.-J.-U.S. 1993 vol. 28, no. 5, pp. 229-230
LA: English
ER: M (Marine)
AB: During the austral spring and autumn long-term ecological research (LTER) cruises aboard the R/V Polar Duke (PD92-09, November 1992) and R/V Nathaniel B. Palmer (NBP93-02, March through May 1993), we had an opportunity to investigate selected sources and sinks of hydrogen peroxide (H sub(2)O sub(2)) in a variety of antarctic coastal habitats. These measurements constituted one component of our comprehensive study of H sub(2)O sub(2) dynamics. The potential source terms we evaluated were wet deposition (snow), glacial ice meltwater and land runoff, and in situ biological processes; photochemical processes are discussed in a companion paper. The primary H sub(2)O sub(2) sink we investigated was bacterial enzymatic activity.
AN: 3885198
77 of 1521
TI: RACER: Nitrogen remineralization within Antarctic sea ice during the 1992 austral winter
AU: Dore,-J.E.; Houlihan,-T.; Karl,-D.M.
AF: Sch. Ocean and Earth Sci. and Technol., Univ. Hawaii, Honolulu, HI 96822, USA
SO: ANTARCT.-J.-U.S. 1993 vol. 28, no. 5, pp. 167-169
LA: English
ER: M (Marine)
AB: Antarctic sea ice provides a number of habitats for thriving microbial communities. Such communities play important roles in the overall ecology of the southern oceans. Although a number of investigations have been made of the sea-ice microbial communities of the Weddell and the McMurdo Sound and Ross Ice Shelf regions, comparatively few data exist on the sea-ice biota of the western Antarctic Peninsula, particularly during the winter. During the final expedition of the Research on Antarctic Coastal Ecosystem Rates program (RACER IV, July and August 1992), several stations along the Antarctic Peninsula were occupied in coastal waters completely covered by the winter ice pack. We describe here data on ammonium distributions and microbial nitrification rates within and below the ice at three of these stations.
AN: 3885179
78 of 1521
TI: RACER: Methane enrichments in Port Foster, Deception Island
AU: Tilbrook,-B.D.; Karl,-D.M.
AF: Commonwealth Scientific and Ind. Res. Organization, Div. Oceanogr., Hobart, Tasmania, 7001, Australia
SO: ANTARCT.-J.-U.S. 1993 vol. 28, no. 5, pp. 165-166
LA: English
ER: M (Marine)
AB: During the research on antarctic coastal ecosystem rates (RACER) program, methane distributions in antarctic coastal waters of the Bransfield Strait, the Gerlache Strait, and in the southern oceans waters of the Drake Passage were examined. The objectives of the study were to identify the factors controlling methane distributions in antarctic shelf and open ocean environments and to evaluate the contribution these regions make to the sea-air flux of methane. As one small component of this larger study, we also occupied a single hydrostation in Port Foster, Deception Island. In this report, we present the water-column methane distribution from this unique, partially submerged volcanic caldera and compare these values with samples collected in surrounding surface waters.
AN: 3885168
79 of 1521
TI: The dynamic of benthic nutrient pools and fluxes in tropical mangrove forests
AU: Alongi,-D.M.
AF: Australian Inst. Mar. Sci., PMB No. 3, Townsville, M.C., Qld. 4810, Australia
SO: J.-MAR.-RES. 1996 vol. 54, no. 1, pp. 123-148
LA: English
ER: M (Marine); B (Brackish)
AB: Variations in benthic nutrient pools and rates of dissolved nutrient exchange between the forest floor and tidal waters were examined over a 5-yr period in mixed Rhizophora forests lining Coral Creek on Hinchinbrook Island in Queensland, Australia. Seasonal and spatial changes in redox status, porewater and solid-phase nutrients, and in exchange rates were not consistent and did not correlate with temperature. Below-ground roots, on average, accounted for similar to 79%, 37% and 26% of bulk sediment TOC, total N and total P pools, respectively. Porewater nutrient concentrations were dominated by Si(OH) sub(4) super(+) and DON with consistently low levels of NO sub(2) super(-) + NO sub(3) super(-). At most sampling periods, porewater NH sub(4) super(+) and PO sub(4) super(3) super(-) concentrations were higher in creek bank sediments than in mangrove sediments indicating uptake by trees. These sediments have low absorption capacity (K = 0.17-0.47) for NH sub(4) super(+), but a moderate capacity (K = 0.8-4.8) for PO sub(4) super(3) super(-) adsorption. Most measured benthic fluxes of dissolved nitrogen and phosphorus showed uptake by sediments, prop roots and timber lying on the forest floor. Mangrove forests are a very efficient sink of dissolved nitrogen, phosphorus and silicon in this tidally-driven coastal ecosystem. This import may be driven by the consistently high rates of microbial and plant growth and productivity within the forests.
AN: 3883421
80 of 1521
TI: On migration, accumulation and circulation of total mercury and methylmercury in ecosystem in the Songhua River
AU: Yu,-Changrong; He,-Ying; Liang,-Dongmei
AF: Environ. Prot. Res. Inst., Jilin Prov., Changchun 130012, People's Rep. China
SO: SHANDONG-FISH.-QILU-YUYE 1995 vol. 12, no. 2, pp. 39-42
LA: Chinese
ER: F (Freshwater)
AB: The total mercury and methylmercury in the Songhua River and its deposits are passed and accumulated in the body of the aquatic animals through the food chain of the aquatic living things which took in the food at each layer of nutrient class. The longer the food chain of the aquatic living things, the more the mercury and methylmercury is accumulated in the body of the aquatic animals. If people eat the polluted fish and chickens, ducks of geese, the total mercury and methylmercury are migrated and deposited in the people's body, thus potentially endangering their health.
AN: 3883354
81 of 1521
TI: Microbiological gas formation altering top sediment composition and its relation to the internal nutrient load in eutrophic lakes
AU: Matinvesi,-J.
AF: Helsinki Univ. Technol., Espoo, Finland
SO: HELSINKI-UNIV.-TECHNOL.,-LAB.-ENVIRON.-PROT.-TECHNOL. 1995 vol. 970, no. 1, 37 pp.
NT: Dissertation for degree of Doctor of Technology.
LA: English
ER: F (Freshwater)
AB: The aim of this investigation was to gain more information on the biological processes taking place in the lake sediments and to find measures to improve the condition of eutrophic lakes. In six central Finnish lakes representing different trophic states, the phosphatase enzyme activity, the number of acetic acid-, ferricphosphate-, and tricalcium-phosphate-utilizing bacteria, and the levels of organic substances were the highest in the top layer of every sediment profile. The top sediments reveal to a great extent a fixed relation of carbon to nitrogen and phosphorus so that biological processes, degradation and deformation, have probably affected the distribution of organic substances and nutrients in the top sediments of these Finnish lakes. This suggests that a part of the organic substances may be mobile within the "reactive zone" and may move to the uppermost sediment layer in the course of time in undisturbed lake sediments. Mixing of organic substances into the water phase will take place in anaerobic conditions when aerobic bacteria are not capable of consuming methane in the sediment-water interface. A lake restoration method is proposed based on an old incident in eastern Finland. In 1859, the level of Lake Hoeytiaeinen was accidentally lowered by 9.5 m. The event is marked by a 2-3 cm dense interlayer of clay and fine silt of deep-water sediments. The layer prevented microbiological interaction between sediment and water. The amounts of LI, BOD sub(7) and tot. N below the clay horizon are comparable to typical undisturbed top sediments in oligotrophic central Finnish lakes. During the 133 years since then, little mineralization in the buried sediment has occurred. Covering bottom deposits with silt and clay (5 to 10 cm) may offer a useful lake restoration method in cases where inner load of nutrients is the main cause for lake eutrophication and where gas formation is not too vigorous in the bottom and where lake morphometry is suitable. BOD analyses give good information of the activity of microbiological processes in top sediment.
AN: 3882982
82 of 1521
TI: Dissolved and particulate nutrient transport through a coastal watershed-estuary system
AU: Smith,-S.V.; Chambers,-R.M.; Hollibaugh,-J.T.
AF: De. Oceanogr., Univ. Hawaii, Honolulu, HI 96822, USA
SO: J.-HYDROL.-AMST. 1996 vol. 176, no. 1-4, pp. 181-203
LA: English
ER: B (Brackish)
AB: Tomales Bay and its adjacent watershed are the location of integrated research on the C-N-P-Si biogeochemical coupling between the land and coastal ocean and cycling of these materials within the bay. In the present paper, budgets have been constructed to describe the rainfall delivery of dissolved nutrients to the watershed and export of dissolved and particulate nutrients from the watershed, mostly in runoff. The quantity of dissolved materials, especially dissolved organic materials, delivered to the watershed by rainfall is about the same as the export: Suspended load transport represents the major net removal of C, N, and P from the watershed, and this flux shows large interannual variation. Runoff-adjusted particle flux from the watershed is small at present in comparison with estimates based on sedimentation rate in the bay over the past 130 years. This difference apparently cannot be explained by natural or managed interannual variation in runoff or by other obvious aspects of water management. We believe that changes in agricultural land use have led to recent decreases in erosion and removal of particulate materials from the watershed. Even though the watershed has been disturbed by agricultural practices over the past 130 years, the system as a whole appears largely to have recovered to steady-state conditions.
AN: 3881216
83 of 1521
TI: Biofilm development and invertebrate colonization of wood in four New Zealand streams of contrasting pH
AU: Tank,-J.L.
AF: Dep. Biol., Virginia Polytech. Inst. and State Univ., Blacksburg, VA 24061, USA
SO: FRESHWAT.-BIOL. 1995 vol. 34, no. 2, pp. 303-315
LA: English
ER: F (Freshwater)
AB: Biofilm development and activity on wood substrata (Nothofagus menziesii) were examined at four forested sites in a South Island, New Zealand, river catchment over a period of 6 months. Two of the sites had brown waters and mean pH of 3.7 and 4.5, whereas the other two had clear waters and mean pH of 6.3 and 6.8. Fungi and other filamentous heterotrophs were the dominant colonizers of wood at all sites; few algal cells were present. Incorporation of super(14)C-glucose by biofilms was greatest in all four streams after 3 months, whereas endocellulase activity fluctuated. Radiotracer experiments with a grazing amphipod (Paraleptamphopus sp.) demonstrated that biofilms on wood from all four sites could be ingested and at least partially assimilated. Chironomid larvae and harpacticoid copepods were the most abundant invertebrates colonizing wood substrata at all sites.
AN: 3880603
84 of 1521
TI: Biogeochemical studies in the Cauvery Estuary, east coast of India
AU: Ramanathan,-A.L.; Subramanian,-V.; Das,-B.K.
AF: Department of Geology, Annamalai University, Chidambaram 608 002, India
SO: INDIAN-J.-MAR.-SCI. 1996 vol. 25, no. 1, pp. 71-73
LA: English
ER: B (Brackish)
AB: Particulate organic carbon and particulate organic nitrogen show a decreasing trend towards the sea. Dissolved silica and phosphorus showed an erratic variation in the Cauvery Estuary. The delta super(13)C shows a marginal conservative behaviour in the Cauvery Estuary. Reduction in the dissolved P and Si concentrations are accompanied by enhanced levels in particulates. Phosphorus in sediments occurred in all the size fractions and possibly exist as a ferric and/or calcium phosphate.
AN: 3880432
85 of 1521
TI: Carbon dioxide and nitrous oxide in the north Indian Ocean
AU: Dileepkumar,-M.; Naqvi,-S.W.A.; Jayakumar,-D.A.; George,-M.D.; Narvekar,-P.V.; deSousa,-S.N.
AF: NIO, Dona Paula, Goa 403 004, India
SO: CURR.-SCI. 1995 vol. 69, no. 8, pp. 672-678
LA: English
ER: M (Marine)
AB: The understanding of biogeochemical cycling of carbon dioxide and nitrous oxide in the oceans is essential for predicting the fate of anthropogenically emitted components. The North Indian Ocean, with its diverse regimes, provides us with a natural laboratory that can unravel the mechanisms controlling these gases with implications for the global aquatic bodies. The anthropogenically impinged global budgets for these gases, largely collected under the Global Change Programme from the North Indian Ocean are reviewed and the contributions from this region to the global sea-to-air fluxes.
AN: 3880169
86 of 1521
TI: Electrochemical study of sulfur species in seawater and marine phytoplankton cultures
AU: Ciglenecki,-I.; Cosovic,-B.
AF: Cent. Marine Res. Zagreb, Rudjer Boskovic Inst., POB 1016, 41001 Zagreb, Croatia
SO: MAR.-CHEM. 1996 vol. 52, no. 1, pp. 87-97
LA: English
AB: Using a direct voltammetric method in seawater samples from the northern Adriatic Sea we have observed a peak at -0.6 V which belongs to sulfur species. The levels of sulfur (expressed as equivalent to sulfide concentrations) ranged between 10 and 50 nM, depending on the season. Maximum concentrations (appr. 500 nM) were found in the surface water during an intensive phytoplankton bloom. Experiments with different phytoplankton cultures (Phaeodactylum tricornutum, Emiliana huxleyi, Tetraselmis suecica, Isochrysis galbana, Prorocentrum micans, Thalassiosira weissflogii and a mixed culture from the Adriatic Sea) incubated with dimethylsulfoniopropionate (DMSP) suggested that this sulfur peak is, in addition to other possible sources, closely connected with degradation processes of DMSP which is a direct or indirect precursor of several marine sulfur species: dimethyl sulfide (DMS), methanethiol (MSH), 3-methiolpropionate (MMPA), 3-mercaptopropionate (MPA), carbonyl sulfide (COS), dimethyl disulfide (DMDS), H2S, S0. The observed voltammetric peak at -0.6 V was stable on acidification and purging procedure, followed by a readjustment of the solution pH to 8-10. The characterization of the electroactive sulfur species responsible for this peak was made by comparison with model substances. No inorganic or organic sulfur species alone revealed completely the voltammetric behaviour of natural samples. We concluded that in seawater and in phytoplankton cultures sulfur is very probably bound and stabilized with organic matter assuming that some of the bound sulfurs are electrochemically active. Our results do not rule out the possibility that some metal sulfides stabilize sulfide in oxic waters too.
AN: 3880094
87 of 1521
TI: Model of carbon cycling in planktonic food webs
AU: Connolly,-J.P.; Coffin,-R.B.
SO: J.-ENVIRON.-ENG. 1995 vol. 121, no. 10, pp. 682-690
LA: English
AB: A mathematical model of carbon fluxes through the heterotrophic microbial food web is developed from a synthesis of laboratory and field research. The basis of the model is the segregation of organic carbon into lability classes that are defined by bioassay experiments. Bacteria, phytoplankton, three trophic levels of zooplankton, and dissolved organic carbon (DOC) and particulate organic carbon (POC) are modeled. The descriptions of bacterial growth and utilization of the various classes of substrate were treated as "universal constants" in the application of the model to three distinct ecosystems, ranging from oligotrophic to highly eutrophic. The successful application of the model to these diverse ecosystems supports the basic validity of the description of the microbial food web and the dynamics of carbon flux. The model indicates that the dynamics of bacteria and protozoan zooplankton production govern the rates of oxidation of carbon entering the water column. Explicit consideration of these groups would improve the capability of eutrophication models to predict dissolved oxygen dynamics, particularly when projecting responses to loading changes.
AN: 3878396
88 of 1521
TI: Evidence for a winter sink of atmospheric carbonyl sulfide in the northeast Atlantic Ocean
AU: Ulshoefer,-V.S.; Uher,-G.; Andreae,-M.O.
SO: GEOPHYS.-RES.-LETT. 1995 vol. 22, no. 19, pp. 2601-2604
LA: English
ER: M (Marine)
AN: 3878377
89 of 1521
TI: Anaerobic methane oxidation on the Amazon shelf
AU: Blair,-N.E.; Aller,-R.C.
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 18, pp. 3707-3715
LA: English
ER: M (Marine)
AB: Anaerobic methane oxidation on the Amazon shelf is strongly controlled by dynamic physical sedimentation processes. Rapidly accumulating, physically reworked deltaic sediments characteristic of much of the shelf typically support what appear to be low rates of steady state anaerobic methane oxidation at depths of 5-8 m below the sediment-water interface. Methane oxidation in these cases is responsible for < similar to 10% of the capital sigma CO sub(2) inventory in the oxidation zone and is limited largely by the steady-state diffusive flux of methane into the overlying sulfate reduction zone. In contrast, a large area of the shelf has been extensively eroded, reexposing once deeply buried (> 10 m) methane-charged sediment directly to sea-water. In this nonsteady-state situation, methane is a major source of recently produced capital sigma CO sub(2) and an important reductant for sulfate. These observations suggest that authigenic sedimentary carbonates derived from anaerobic methane oxidation may sometimes reflect physically enhanced nonsteady-state exposure of methane to sulfate in otherwise biogeochemically unreactive deposits. The concentration profiles of CH sub(4), SO sub(4) super(=), and capital sigma CO sub(2) in the eroded deposit were reproduced by a coupled reaction-transport model. This area of the shelf was reexposed to seawater approximately 5-10 years ago based on the model results and the assumption that the erosion of the deposit occurred as a single event that has now ceased. The necessary second order rate constant for anaerobic methane oxidation was greater than or equal to 0.1 mM/d.
AN: 3878370
90 of 1521
TI: CO sub(2) transfer at the air-sea interface: Numerical tests of the dual-tracer method
AU: Phillips,-L.F.
AF: Chem. Dep., Univ. Canterbury, Christchurch, New Zealand
SO: GEOPHYS.-RES.-LETT. 1995 vol. 22, no. 19, pp. 2597-2600
LA: English
ER: M (Marine)
AB: Gas-water fluxes of CO sub(2), O sub(2), He, SF sub(6) and NH sub(3) have been calculated for conditions corresponding to the measurements of Liss et al for O sub(2) exchange and of Smith and coworkers for CO sub(2) exchange. For each experimental run, the best value of surface temperature was selected by matching the calculated transfer velocity to the measured value for O sub(2) or CO sub(2), and fluxes of the other gases were then calculated for steady state, boundary layer, surface renewal and eddy diffusion models. The results indicate that the dual tracer method should work well for sparingly soluble gases under conditions where a surface renewal model applies, and moderately well under conditions where the boundary layer model is appropriate, but they leave open the question of when such models should apply.
AN: 3878369
91 of 1521
TI: The labyrinth of nutrient cycles and buffers in wetlands: Results based on research in the Camargue (southern France)
AU: Golterman,-H.L.
AF: Association 'Leiden-Camargue', Stn. Biologique de la Tour du Valat, Le Sambuc, F-13200 Arles, France
SO: HYDROBIOLOGIA 1995 vol. 315, no. 1, pp. 39-58
NT: Special issue: Nutrient cycles.
LA: English
ER: F (Freshwater)
AB: In this article different aspects of nutrient cycles are discussed in view of approaching a sufficiently precise quantification. The nutrient input balance of the Camargue was therefore measured which showed that the input of nutrients with the irrigation water, taken from the River Rhone, roughly equals the quantity of fertilizers added. Phytoplankton growth can be approached reasonably with the Monod model, although there are still many practical problems, such as the influence of the pH on P uptake and the problem of measuring P uptake in the field. The situation is worse for macrophyte growth; quantitative data are scarce and studies have often been carried out with unrealistic nutrient concentrations or without addressing the influence of the sediment. This influence can also include negative factors, such as high concentrations of Fe super(2+), H sub(2)S or FeS, but cannot yet be quantified. The nitrogen cycle in wetlands is dominated by denitrification. Most wetlands have sediments with high concentrations of organic matter, therefore with a large reducing capacity. Besides this process, we have shown that denitrification can also be controlled by FeS. In the Camargue sediments this denitrification is mediated by bacteria from the sulfur cycle; this appeared to be the major pathway.
AN: 3878334
92 of 1521
TI: Phytoplankton as an increasingly compound photosynthetic system: A historical perspective
AU: Talling,-J.F.
AF: Freshwater Biol. Association, Ambleside, Cumbria LA22 0LP, UK
SO: HYDROBIOLOGIA 1995 vol. 315, no. 1, pp. 9-14
NT: Special issue: Nutrient cycles.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The original suggestion that phytoplankton can be viewed and modelled as a compound photosynthetic system combined light gradients with depth and biological plus chemical homogeneity. Subsequent experience often involved biological and chemical differentiation in depth and time. Such differentiation is surveyed; it can add to the compound structure, and modify the kinetics of depth-integrated photosynthetic production. Further compounding possibilities are introduced by alternatives in carbon input, output and storage; also, conceptually, by the level of approach adopted. These features are discussed in historical perspective.
AN: 3878331
93 of 1521
TI: The carbonic system distribution and fluxes in the NE Atlantic during spring 1991
AU: Rios,-A.F.; Anderson,-T.R.; Perez,-F.F.
AF: Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Cientificas (CSIC), Eduardo Cabello, 6, 36208 Vigo, Spain
SO: PROG.-OCEANOGR. 1995 vol. 35, no. 4, pp. 295-314
LA: English
ER: M (Marine)
AB: The potential of the North Atlantic as a sink for atmospheric CO sub(2) was investigated by studying the carbonic system using data obtained during the spring of 1991. The air-sea flux of CO sub(2) was related to chlorophyll and other environmental variables, and the regeneration of carbon in the mid-ocean studied by examining vertical sections representative of the study area. Poor correlations were found between pCO sub(2) and chlorophyll throughout much of the study area, although a good correlation was found along 16 degree W. The highest air-sea fluxes of CO sub(2) were calculated for areas where chlorophyll was highest (45 degree 13'N, 16 degree 04'W), and where the greatest wind speeds occurred (47 degree 51'N, 28 degree 18'W). The mean CO sub(2) flux from the atmosphere to the ocean during the study period (May) was calculated as 0.65mmol m super(-2)d super(-1), which compares well with other studies. Regression equations were developed to predict total inorganic carbon from nutrients; errors were typically less than 1 mu mol kg super(-1). Regeneration of carbon in the mid-ocean occurred in two principal stages: 0-1000m and >2300m. Regeneration in the upper zone was dominated by soft tissue carbon (86%), with skeletal carbon (calcite) contributing only 14%. The fraction of regenerated carbon of skeletal origin increased to 51% in the >2300m zone.
AN: 3877855
94 of 1521
TI: Carbon and phosphorus transport by the major Indian rivers
AU: Ramesh,-R.; Purvaja,-G.R.; Subramanian,-V.
AF: Cent. for Water Resour., Anna Univ., Madras, India
CO: 1. GCTE Science Conference, Woods Hole, MA (USA), 23-27 May 1994
SO: J.-BIOGEOGR. 1995 vol. 22, no. 2-3, pp. 409-415
LA: English
ER: F (Freshwater)
AB: Riverine systems play a major role in the transport of nutrients from the land masses and atmosphere to the oceans and frequently serve as reservoirs for numerous compounds. The biogeochemical cycling of elements is significantly affected by man's activities. With the growing awareness of human impact on quality of rivers, emphasis is given more towards a holistic treatment of a river as an ecosystem. In the present study, an attempt is made to estimate the organic carbon transport from the Himalayan rivers. The transfer of dissolved organic carbon (DOC) and particulate organic carbon (POC) from the Himalayan rivers is estimated to be about 7.6 and 9 million tons per year. High concentrations of P-PO sub(4) are found in all the Indian rivers, which may be due to human interference. Pronounced temporal and seasonal variation for DOC and P-PO sub(4) have been reported. The flux of P-PO sub(4) and particulate inorganic phosphorus (PIP) from the Indian rivers to the ocean is 19.5 x 10 super(10) g yr super(-1) and 1.5 x 10 super(12) g yr super(-1) respectively. Comparisons were made with the prominent world rivers.
AN: 3874423
95 of 1521
TI: Structure and productivity of a 20-year-old stand of Rhizophora apiculata Bl. mangrove forest
AU: Jin-Eong,-O.; Khoon,-G.W.; Clough,-B.F.
AF: Cent. for Marine and Coastal Studies, Universiti Sains Malaysia, 11800 Penang, Malaysia
CO: 1. GCTE Science Conference, Woods Hole, MA (USA), 23-27 May 1994
SO: J.-BIOGEOGR. 1995 vol. 22, no. 2-3, pp. 417-424
LA: English
ER: B (Brackish)
AB: Mangroves are dominant interface ecosystems between the land and the sea in the tropics, and are of importance in the economy of many of these regions in terms of mangrove-linked fisheries and forestry. Recently, mangroves have been of particular interest in relation to global change both because of the possible high carbon sequestration as well as being in the 'forefront' of any sea-level change, because of their location. To understand the impact of global change on these ecosystems (considered terrestrial and aquatic at the same time) and vice versa, it is necessary to obtain 'a more comprehensive and realistic picture of the terrestrial carbon cycle', which is one of the aims of the GCTE Programme. We therefore present here some of the results of our long-term study (started in the mid-1970s) on the carbon and nutrient budget of a mangrove ecosystem as a basis for further studies, including the proposed large-scale biogeochemical transects and climate models proposed by GCTE. The tree density of the 20 m X 40 m plot in the 20-year-old stand was equivalent to 2425 stems per hectare (1975 live trees per hectare). Size (girth at breast height) of Rhizophora apiculata trees ranged from 9 to 75.5 cm with a mean at 39 cm. The smallest live tree weighed 10 kg and the biggest weighed 510 kg with a mean biomass of 122 kg. About 70% of the trees were below 100 kg but the 30% of the bigger trees contributed to slightly more than half of the total biomass of the plot. The canopy had an average height of 21 m. The total standing biomass was 114 t C ha super(-1); 74% of the biomass was in the trunk, 15% in the roots (10% in stilts and 5% below-ground) and 10.6% in the canopy (only 2.6% in leaves). Using allometric regressions, we obtained a net productivity (root turnover and loss through leaching were not measured but only approximated as equal to small litter production) of 17 plus or minus 5 t C ha super(-1) yr super(-1). If greater accuracy (than plus or minus 30%) is needed, direct measurements of root turnover and leaching from roots would be needed. Using the gas exchange method and using the mean value for a whole day's net photosynthesis measurements (averaged at 6 mu mol m super(-2) s super(-1)), 1.5 mu mol m super(-2) s super(-1) for leaf respiration, a leaf area index of 4, and assuming respiration of the non-leaf tissues to be the same as for leaves, we estimated net productivity to be 11.35 t ha super(-1) yr super(-1), almost at the lower limit of the allometric estimate. Use of leaf to tree to stand models may improve the accuracy of this method. The main gaps are in fine root turnover and possible loss of carbon through leaching from the roots.
AN: 3870303
96 of 1521
TI: The role of microorganisms in biosorption of toxic metals and radionuclides
AU: White,-C.; Wilkinson,-S.C.; Gadd,-G.M.*
AF: Dep. Biol. Sci., Univ. Dundee, Dundee DD1 4HN, UK
CO: Symposioum on Biosorption and Bioremediation, Madrid (Spain), 17-19 Oct 1993
SO: BIOSORPTION-AND-BIOREMEDIATION. Laborda,-F.;Beech,-I.B.;Sylvestre,-M.-eds. 1995 vol. 35, no. 1-3 pp. 17-40
ST: INT.-BIODETERIOR.-BIODEGRAD. vol. 35, no. 1-3
LA: English
AB: A multiplicity of physico-chemical and biological mechanisms determine the removal of toxic metals, metalloids and radionuclides from contaminated wastes. Physico-chemical mechanisms of removal, which may be encompassed by the general term "biosorption", include adsorption, ion exchange and entrapment which are features of living and dead biomass as well as derived products. In living cells, biosorption can be directly and indirectly influenced by metabolism. Metabolism, dependent mechanisms of metal removal which occur in living microorganisms include metal precipitation as sulphides, complexation by siderophores and other metabolites, sequestration by metal-binding proteins and peptides, transport and intracellular compartmentation. In addition, transformations of metal species can occur resulting in oxidation, reduction or methylation. For metalloids such as selenium, two main transformation mechanisms are the reduction of oxyanions to elemental forms, and methylation to methylated derivatives which are volatilized. Such mechanisms are important components of natural biogeochemical cycles for metals and metalloids as well as being potential application for bioremediation.
AN: 3868598
97 of 1521
TI: Distribution of biological activity in the lower St Lawrence Estuary as determined by multivariate analysis
AU: Savenkoff,-C.; Chanut,-J.-P.; Vezina,-A.F.; Gratton,-Y.
AF: Dep. Fish. and Oceans, Maurice-Lamontagne Inst., P.O. Box 1000, Mont-Joli, PQ G5H 3Z4, Canada
SO: ESTUAR.-COAST.-SHELF-SCI. 1995 vol. 40, no. 6, pp. 647-664
LA: English
ER: M (Marine)
AB: Three stations located in the Laurentian Trough were investigated three times during the summer production maximum (in June-July 1990; COUPPB90-1 cruise). A range of multivariate analyses was carried out to extract major physical-biological features in a large data set covering the whole cruise. This study presents the advantages of combining conventional principal component analysis (PCA) with a three-way data analysis. PCA provides the centre of gravity of the different locations for each variable and each sample during the cruise without temporal information. Three-way data analysis produces the trajectory of the different site/time locations for each variable and each sample, and clarifies spatial and temporal relationships between variables. The results reproduce the main patterns of the lower St Lawrence Estuary during the summer plankton bloom and indicate an upstream movement of warm and less saline waters associated with surface production. Apparently these large changes at the surface are not reflected in the deeper layers. Cluster analysis suggests that autotrophic and heterotrophic activities are decoupled when production is low and are correlated only when production increases.
AN: 3865608
98 of 1521
TI: Effects of zooplankton on sedimentation in pelagic ecosystems: Theory and test in two lakes of the Canadian shield
AU: Elser,-J.J.; Foster,-D.K.; Hecky,-R.E.
AF: Dep. Zool., Arizona State Univ., Tempe, AZ 85287-1501, USA
SO: BIOGEOCHEMISTRY 1995 vol. 30, no. 3, pp. 143-170
LA: English
ER: F (Freshwater)
AB: A simple heuristic theory based on conservation of matter and describing the fate of autotrophic production in pelagic ecosystems was developed to assist in conceptualizing how zooplankton affect sedimentation processes in lakes and oceans. The theory predicted that effects of zooplankton on the fraction of autotrophic incorporation that sediments (the "export ratio") will be a function of factors related both to zooplankton digestion and egestion and to tendencies of particulate matter to sediment directly prior to mineralization. As a result, effects of zooplankton grazing on the export ratio were predicted to be site-dependent, a function of physical conditions and zooplankton communities characterizing an ecosystem. The theory was tested by monitoring autotrophic production of C, N, and P, sedimentation of C, N, and P, and zooplankton biomass in two lakes of the Canadian shield characterized by contrasting morphometry and food-web structure. In Lake 110, a small elongate lake protected from wind exposure, export ratios of C, N, and P declined strongly with zooplankton biomass. In contrast, in L240, a larger lake with considerably greater wind exposure, export ratios increased with zooplankton biomass. These results were consistent with predictions of our theory that effects of zooplankton on sedimentation processes will depend on the tendency of particulate matter to directly sediment relative to the tendency of egested materials to sediment. However, no significant differences in relationships between export ratios for C, N, and P and zooplankton biomass were found.
AN: 3865603
99 of 1521
TI: Seasonal sedimentation of autochthonous material from the euphotic zone of a coastal system
AU: Olesen,-M.; Lundsgaard,-C.
AF: Mar. Biol. Lab., Univ. Copenhagen, DK-3000 Helsinger, Denmark
SO: ESTUAR.-COAST.-SHELF-SCI. 1995 vol. 41, no. 4, pp. 475-490
LA: English
ER: M (Marine)
AB: The seasonal sedimentation of particulate matter across the pycnocline was recorded in the Kattegat during the period of stratification (March-October 1989). The proportion of viable phytoplankton cells of the total carbon flux (63 g C/m super(2)) was low (18%). Faecal pellets contributed on average less than 5%. The major component of the sinking matter consisted of detrital material (amorphous particles with few recognizable components) which was estimated mainly to originate from the activity of microzooplankton. The average C/N ratio of the particulate biogenic matter trapped at the pycnocline was 8.6, but only 6.4 for the suspended particulate organic matter in the mixed layer indicating that nitrogen is more effectively recycled than carbon in the euphotic zone. This mechanism allows for an additional new organic carbon production of 33% compared to that which can be estimated from the external loading of nitrogen. Over the entire period the average daily vertical flux of carbon corresponded to 14% of the phytoplankton biomass indicating a high efficiency in the transport of organic material from the euphotic zone to the bottom.
AN: 3863766
100 of 1521
TI: Predictive model of the effects on lake metabolism of decreased airborne litterfall through riparian deforestation
AU: France,-R.L.; Peters,-R.H.
AF: Dep. Biol., McGill Univ., 1205 Ave. Dr. Penfield, Montreal, PQ H3A 1B1, Canada
SO: CONSERV.-BIOL. 1995 vol. 9, no. 6, pp. 1578-1586
LA: English
ER: F (Freshwater)
AB: The importance of airborne allochthonous litter to the carbon and nutrient budgets of lakes has been seldom studied. We compiled data on the input of terrestrial litter to develop a simple and speculative model to predict the potential consequences of riparian deforestation on one aspect of lake metabolism, specifically the balance between phytoplankton production and plankton respiration. During the autumn of 1992, 56 litter traps were deployed around the littoral zones of four oligotrophic lakes in a densely forested region of northwestern Ontario, Canada. The airborne litter input was estimated to be 32 g dry weight per meter of forested shoreline per year. Allochthonous litter input per unit offshore distance was related to the size of riparian trees, their proximity to the shoreline, and the elevation of their canopy. Combining our data with those from other studies suggests that terrestrial litter can contribute up to 15% of the total carbon supply to oligotrophic lakes and up to 10% of the total phosphorus supply to lakes with a large surface area relative to that of their drainage basin. These results were incorporated into a simple model that predicts that removal of shoreline trees could increase the ratio of plankton production to respiration in oligotrophic lakes situated within small drainage basins. Such lakes may therefore shift from allotrophy to increasing autotropy (energy self-sustenance) following riparian deforestation.
AN: 3863225
101 of 1521
TI: Organic carbon transport from the Southern Ocean and bacterial growth in the Antarctic intermediate water masses of the Tasman Sea
AU: Moriarty,-D.J.W.; O'-Donohue,-M.J.
AF: ARDA-Tek, 315 Main Rd. Wellington Point, Qld. 4160, Australia
SO: MAR.-ECOL.-PROG.-SER. 1995 vol. 119, no. 1-3, pp. 291-297
LA: English
ER: M (Marine)
AB: The concept that organic carbon is transported to the equatorial region at intermediate water depths from subantarctic frontal zones has been re-investigated using the tritiated thymidine method to determine rates of bacterial DNA synthesis in water masses of the Tasman Sea. There was a higher bacterial growth rate and thus a higher flux of organic carbon through bacteria in the Antarctic Intermediate Water (900 to 1000 m depth) than in the water masses immediately above or below in the Tasman Sea east and south of Tasmania. Values for bacterial production were 4 to 8 mu g C/m super(3)/d, which are equivalent to a consumption of about 3 to 6 mu l O sub(2)/l/yr. In the deeper layer at 1200 to 1500 m, rates were 3 to 4 times lower. These rates are compatible with other data on oxygen utilisation. Our results support the concept that organic matter sinks with downwelling water in the zone between the Subtropical Convergence and the Polar Front in the Southern Ocean and is advected towards the equator below the photic zone.
AN: 3862994
102 of 1521
TI: Role of a dense bed of Ophiothrix fragilis (Abildgaard) in the transfer of heavy metals at the water-sediment interface
AU: Gounin,-F.; Davoult,-D.; Richard,-A.
AF: Stn. Mar. (URA-CNRS 1363), Wimereux, France
SO: MAR.-POLLUT.-BULL. 1995 vol. 30, no. 11, pp. 736-741
LA: English
ER: M (Marine)
AB: The role of a dense bed of suspension-feeders (Ophiothrix fragilis) on the biogeochemical cycle of five major metals has been studied in the English Channel (Fe, Mn, Pb, Cu, Cd). Metal concentrations in ophiurids, their food (=suspended matter) and their faeces did not show any significant time variation. After their transit between food, organisms and faeces, metal concentrations were poorly modified, but relations between them changed. A lot of trace elements have been detected in the stomach, some of them typical of the waste inputs above the site. So, the ophiurid O. fragilis can be considered as a biological indicator of the elemental composition of the water mass entering the North Sea.
AN: 3862287
103 of 1521
TI: The formation of surface-active organic complexes of copper in coastal marine waters
AU: Shine,-J.P.; Wallace,-G.T.
AF: Environ. Sci. Program, Univ. Massachusetts at Boston, 100 Morrissey Blvd., Boston, MA 02125, USA
SO: MAR.-CHEM. 1995 vol. 51, no. 2, pp. 145-157
LA: English
ER: M (Marine)
AB: The importance of surface-active organic matter on the speciation of copper in coastal seawater was examined over a 22 month period in Massachusetts Bay. Concentrations of copper associated with dissolved surface-active organic matter ranged from 15 pmol/kg during winter (0.67% of total dissolved copper) to 850 pmol/kg (18% of total dissolved copper) at the peak of primary production during a spring bloom and, following a spring bloom, accounted for 36% of the total dissolved copper concentration. Association of copper with surface-active organic matter may have occurred by direct complexation with surface-active organic ligands or indirectly via organic-organic interactions with non-surface-active organic complexes of copper. Although total dissolved copper at the site was inversely related to salinity, indicative of freshwater/continental sources, the amount of copper bound to surface-active organic matter was significantly correlated with estimated rates of phytoplankton primary production (r super(2) = 0.78). The primary source of surface-active organically bound copper in Massachusetts Bay is apparently in-situ biological production and not export of anthropogenic/freshwater ligands from continental sources. Although they represent a small but significant fraction of the total copper species present in coastal seawater, surface-active forms of copper assume added importance due to their active role in the transport and biogeochemical cycling of this element.
AN: 3861713
104 of 1521
TI: A discussion on vertical profiles of dissolved Cu, Cd and Ni in the northwestern Pacific, South of Japan
AU: Wang,-Zhengfang; Junichi,-O.
AF: 2nd Inst. Oceanogr., SOA, Hangzhou 310012, People's Rep. China
SO: ACTA-OCEANOL.-SIN.-HAIYANG-XUEBAO 1993 vol. 12, no. 4, pp. 597-603
LA: English
ER: M (Marine)
AB: Some of the results about vertical profile of heavy metals of seawater to the South of Japan in Oct. 1990 are presented and discussed in relation to the concentration of dissolved Cu, Cd and Ni to biogeochemical environments. It points out that the distribution of dissolved Cu is higher in surface water than that in/upper 500 m layer, and maxima value attains the 8.2 n mol/dm super(3) in depth of 4 000 m. The concentrations of dissolved Ni ranges from 3.4 n mol/dm super(3) in surface seawater to 8.5 n mol/dm super(3) in the deep seawater to the South of Japan. The highest values are observed in the colder waters. This paper shows also that the vertical profile of dissolved Cd is perfect nutrient-type distribution. Dissolved Cd and phosphate are linearly correlated by the regression equation.
AN: 3860125
105 of 1521
TI: Seasonal flooding, nitrogen mineralization and nitrogen utilization in a prairie marsh
AU: Neill,-C.
AF: Ecosyst. Cent., Mar. Biol. Lab., Woods Hole, MA 02543, USA
SO: BIOGEOCHEMISTRY 1995 vol. 30, no. 3, pp. 171-189
LA: English
ER: F (Freshwater)
AB: Flooding can be an important control of nitrogen (N) biogeochemistry in wetland ecosystems. In North American prairie marshes, spring flooding is a dominant feature of the physical environment that increases emergent plant production and could influence N cycling. I investigated how spring flooding affects N availability and plant N utilization in whitetop (Scolochloa festucacea) marshes in Manitoba, Canada by comparing experimentally spring-flooded marsh inside an impoundment with adjacent nonflooded marsh. The spring-flooded marsh had net N mineralization rates up to 4 times greater than nonflooded marsh. Total growing season net N mineralization was 124 kg N ha super(-1) in the spring-flooded marsh compared with 62 kg N ha super(-1) in the nonflooded marsh. Summer water level drawdown in the spring-flooded marsh decreased net N mineralization rates. Net nitrification rates increased in the nonflooded marsh following a lowering of the water table during mid summer. Growing season net nitrification was 33 kg N ha super(-1) in the nonflooded marsh but <1 kg N ha super(-1) in the spring-flooded marsh. Added No sub(3) super(-) induced nitrate reductase (NRA) activity in whitetop grown in pot culture. Field-collected plants showed higher NRA in the nonflooded marsh. Nitrate comprised 40% of total plant N uptake in the nonflooded marsh but <1% of total N uptake in the spring-flooded marsh. Higher plant N demand caused by higher whitetop production in the spring-flooded marsh approximately balanced greater net N mineralization. A close association between the presence of spring flooding and net N mineralization and net nitrification rates indicated that modifications to prairie marshes that change the pattern of spring inundation will lead to rapid and significant changes in marsh N cycling patterns.
AN: 3860017
106 of 1521
TI: Role of benthic communities in organic contaminant (PAH, PCB) transport and fate. 2. Bioaccumulation and biotransformation
AU: Lay,-P.W.; Dickhut,-R.M.; Schaffner,-L.C.; Mitra,-S.
AF: Sch. Mar. Sci., Coll. William and Mary, Virginia Inst. Mar. Sci., Gloucester Point, VA 23062, USA
CO: 37. Conference of the International Association of Great Lakes Research and Estuarine Research Federation, Windsor, ON (Canada), 5-9 Jun 1994
SO: 37TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH-AND-ESTUARINE-RESEARCH-FEDERATION:-PROGRAM-AND-ABSTRACTS. International-Assoc.-for-Great-Lakes-Research,-Buffalo,-NY-USA BUFFALO,-NY-USA IAGLR 1994 166
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Numerous macrobenthic organisms from lower Chesapeake Bay have been observed to rapidly accumulate and transform a series of organic contaminants (OCs). Bioaccumulation and biotransformation vary both within and among major taxa, and with the OC physical-chemical properties (e.g., desorption rate, diffusivity, octanol/water partition coefficient - K sub(OW)). Nonetheless, bioaccumulation of OCs is rapid for various organisms regardless of feeding behavior (e.g., surface and head-down deposit feeders, predators) indicating that uptake of contaminants from the dissolved phase may be important. Comparison of OC and metabolite body burdens to those in the corresponding sediment indicate three types of behavior for OC fluxes through the organisms over 56 days of exposure to contaminated sediments: [1] steady state between contaminant uptake and elimination, [2] faster uptake than elimination corresponding to increasing bioaccumulation, and [3] rapid loss relative to uptake, with decreasing bioaccumulation factors with time. OC loss mechanisms from operationally defined detectable pools in the benthic biota may include: elimination of parent or metabolites, and binding of reactive metabolites to cellular structures. OC fate and transport pathways within benthic organisms are of importance in determining both the direct and indirect effects of organic pollutants on aquatic ecosystems including trophic transfer of parent compounds and toxic metabolites.
AN: 3859635
107 of 1521
TI: Modeling hydrophobic organic contaminant trophic transfer in the mesohaline Chesapeake Bay
AU: Kucklick,-J.R.; Madden,-J.; Baker,-J.E.; Kemp,-W.M.; Cheng,-Chung-Chi; Ko,-F.C.
AF: Chesapeake Biol. Lab., Univ. Maryland Syst., P.O. Box 38, Solomons, MD 20688, USA
CO: 37. Conference of the International Association of Great Lakes Research and Estuarine Research Federation, Windsor, ON (Canada), 5-9 Jun 1994
SO: 37TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH-AND-ESTUARINE-RESEARCH-FEDERATION:-PROGRAM-AND-ABSTRACTS. International-Assoc.-for-Great-Lakes-Research,-Buffalo,-NY-USA BUFFALO,-NY-USA IAGLR 1994 166
NT: Summary only.
LA: English
ER: B (Brackish)
AB: A simulation model was constructed to help elucidate processes influencing the trophic transfer of hydrophobic organic contaminants in Chesapeake Bay. The model differs from other trophic transfer models by focusing on lower trophic levels, such as phytoplankton and zooplankton, and incorporating a fairly sophisticated trophic carbon flow model for the mesohaline bay. Contaminants are introduced into the food web by passive diffusion, which is affected by exchange area and water-organism mass transfer coefficients, and feeding. The model was calibrated using a data set on seasonal PCB (congener specific) concentrations and distributions in size fractioned particles and water from the mesohaline Chesapeake Bay at two depths. This data set contains PCB congener concentrations in 2-10 mu m, 10-64 mu m, 64-202 mu m, and >202 mu m particles, which in the model represent ciliates and nanophytoplankton, phytoplankton and microheterotrophs, larger phytoplankton, and zooplankton, respectively. Lipid and carbon concentrations for each of the size classes are also contained in the data set and are used in the model. This talk presents the overall model structure as well as results from seasonal simulations and a sensitivity analysis on HOC transfer parameters.
AN: 3859633
108 of 1521
TI: Chemical correlates of Hg and methyl-Hg in northern Wisconsin lake waters under ice-cover
AU: Watras,-C.J.; Morrison,-K.A.; Bloom,-N.S.
AF: WI Dep. Nat. Resour., Univ. Wisconsin, Trout Lake Stn., 10810 CTY N, Boulder Junction, WI 54512, USA
SO: WATER,-AIR,-SOIL-POLLUT. 1995 vol. 84, no. 3-4, pp. 253-267
LA: English
ER: F (Freshwater)
AB: Total and dissolved concentrations of Hg and methyl-Hg (MeHg) were determined in the surface waters of 19 northern Wisconsin lakes under ice-cover when differences due to temperature, hydrology, productivity, and atmospheric exchange were minimal. Measured concentrations ranged from 0.3 to 5.3 ng/L for HgT and from 0.01 to 2.8 ng/L for MeHgT. Dissolved species comprised 30% to 95% of the HgT and MeHgT. MeHg was strongly correlated with Hg for both total and dissolved fractions. Thirteen ancillary constituents were measured in conjunction with the Hg determinations (pH, DOC, DIC, DO sub(2), conductivity, suspended particulate matter (SPM), Ca, Mg, Mn, Fe, Na, SO sub(4), Cl). Simple linear regressions indicated that DOC explained 87% of the variability in HgT and 79% of the variability in MeHgT. Of the other measured variables, pH, DO sub(2), Fe and Mn showed weak but significant simple correlations with Hg and MeHg (p < 0.05). Multiple regression models containing two independent variables, (DOC and pH), explained 92% of the variability in HgT and 83% of the variability in MeHgT. Models containing DOC alone fit the dissolved Hg data well. We conclude that organic carbon concentrations have a strong effect on the concentrations of Hg and MeHg in these lakewaters.
AN: 3857836
109 of 1521
TI: Winter-summer differences of carbon dioxide and oxygen in the Weddell Sea surface layer
AU: Hoppema,-M.; Fahrbach,-E.; Schroeder,-M.; Wisotzki,-A.; De-Baar,-H.J.W.
AF: Alfred-Wegener-Inst. Polar- und Meeresforschung P.O. Box 120161, D-27515 Bremerhaven, FRG
SO: MAR.-CHEM. 1995 vol. 51, no. 3, pp. 177-192
LA: English
ER: M (Marine)
AB: Mid-winter total inorganic carbon (TCO sub(2)) and oxygen measurements are presented for the central fully ice-covered Weddell Sea. Lateral variations of these properties in the surface layer of the central Weddell Sea were small but significant. These variations were caused by vertical transport of Warm Deep Water into the surface layer and air-sea exchange before the ice cover. Oxygen saturation in the surface layer of the central Weddell Sea was near 82%, whereas in the eastern shelf area this was 89%. Surprisingly, pCO sub(2), as calculated under the assumption of (reported) conservativeness of alkalinity, was also found to be below saturation (86-93%). This was not expected since ongoing Warm Deep Water entrainment into the surface layer tends to increase the pCO sub(2). Rapid cooling and subsequent ice formation during the previous autumn, however, might have brought about a sufficiently low undersaturation of CO sub(2), that as to the point of sampling had not yet been replenished through Warm Deep Water entrainment. In the ensuing early summer the measurements were repeated. In the shelf area and the central Weddell Sea, where the ice-cover had almost disappeared, photosynthesis had caused a decrease of pCO sub(2) and an increase of oxygen compared to the previous winter. In between these two regions there was an area with significant ice-cover where essentially winter conditions prevailed. Based on the summer-winter difference a (late-winter) entrainment rate of Warm Deep Water into the surface layer of 4-5 m/month was calculated. A complete surface water balance, including entrainment, biological activity and air-sea exchange, showed that between the winter and summer cruises CO sub(2) and oxygen had both been absorbed from the atmosphere. The TCO sub(2) increase due to entrainment of Warm Deep Water was partly countered by (autumn) cooling, and partly through biological drawdown. Part of the CO sub(2) removed through biological activity sinks down the water column as organic material and is remineralised at depth. It is well-known that bottom water formation constitutes a sink for atmospheric CO sub(2). However, whether the Weddell Sea as a whole is a sink for CO sub(2) depends on the ratio of two counteracting processes, i.e. entrainment, which increases CO sub(2) in the surface and the biological pump, which decreases it. As deep water is not only entrained into the surface, but also conveyed out of the Weddell Sea, the relative importances of these (CO sub(2)-enriched) deep water transports are important as well.
AN: 3855921
110 of 1521
TI: Formation of recalcitrant organic matter: Humification dynamics of algal derived dissolved organic carbon and its hydrophobic fractions
AU: Lara,-R.J.; Thomas,-D.N.
AF: Alfred-Wegener-Inst. Polar- und Meeresforschung, Am Handelshafen 12, D-27570 Bremerhaven, FRG
SO: MAR.-CHEM. 1995 vol. 51, no. 3, pp. 193-199
LA: English
ER: M (Marine)
AB: The incorporation of radiolabeled carbon into XAD2-fractions of dissolved organic matter was followed during the growth, stationary and degradation phases of a batch culture of the Antarctic diatom Thalassiosira tumida. Changes in the fractions over the 267 day experiment were correlated with the production and decomposition of particulate organic matter. The bulk of the acid and neutral hydrophobic XAD-fractions, traditionally considered to be humic, were produced mainly during the diatom growth phase: 70% of this carbon was present in a relatively stable form by the end of the first month, representing 5% of the maximum carbon biomass. There was a progressive accumulation of a hydrophobic DOC fraction tightly bound to the XAD resin. This fraction is normally not considered following XAD2 extraction of aquatic humic material. However, it is evidently an important component of a resistant DOC pool, increasing during the experiment to levels between 40 and 50% of total DOC after 7-8 months. This fraction is thought to be mainly a product of particulate material degradation. At the end of the experiment the sum of all hydrophobic DOC fractions was 14% of the maximum particulate carbon.
AN: 3855920
111 of 1521
TI: Mineralization of dissolved organic carbon in the Sargasso Sea
AU: Hansell,-D.A.; Bates,-N.R.; Gundersen,-K.
AF: Bermuda Biol. Stn. Res., Inc., 17 Biological Lane, St. Georges, GE-01, Bermuda
SO: MAR.-CHEM. 1995 vol. 51, no. 3, pp. 201-212
LA: English
ER: M (Marine)
AB: The lability of dissolved organic carbon was estimated in the Sargasso Sea. Rates of DOC mineralization were estimated by monitoring, with high precision, the accumulation of CO sub(2) in dark incubation bottles after the removal of particles >0.8 mu m in size. The minimum incubation time used in these experiments was 24 h. Rates from three 24 h incubations conducted on water from 20 m fell in the narrow range of 0.44-0.45 mu M C d super(-1). These rates ranged from approximate equivalence to more than 100% greater than the concurrent rates of primary productivity, suggesting in some cases that gross primary productivity was underestimated or that there existed labile DOC produced earlier in time, thus supporting periods of net heterotrophy in the Sargasso Sea.
AN: 3855919
112 of 1521
TI: Carbon-isotope composition of sediments from the Gulf of Papua
AU: Bird,-M.I.; Brunskill,-G.J.; Chivas,-A.R.
AF: Res. Sch. Earth Sci., Australian Natl. Univ., Canberra, ACT 0200, Australia
SO: GEO-MAR.-LETT. 1995 vol. 15, no. 3-4, pp. 153-159
NT: Special issue: Tropical coastal sedimentary environments.
LA: English
ER: M (Marine)
AB: Rivers draining into the Gulf of Papua (GOP) from the Papua New Guinea mainland deliver approximately 340 x 10 super(6) t yr super(-1) of sediment to the marine environment. The terrestrially derived sediment contains 1.1 plus or minus 0.2% particulate organic carbon with a carbon-isotope composition of -26.5 plus or minus 0.2ppt, and amounts to 3.7 plus or minus 0.7 x 10 super(6) t yr super(-1). The carbon-isotope composition of sediments in the Gulf of Papua indicates that 40% of the sediment cover contains 75% or more terrestrially derived carbon. Suspended sediments that are transported beyond the delta complex of the Fly River are transported north and northwest, augmented by sediments from other rivers along the coast of the GOP. The carbon-isotope results suggest that a significant quantity of terrestrially derived sediment escapes from the GOP, either along the coastlines to east and west or into the deep ocean via the Moresby and Pandora troughs. Little sediment travels south onto the Great Barrier Reef shelf. Extrapolating the results from this study to the region of Oceania suggests a total flux of particulate organic carbon to the world's oceans from the islands of Oceania of similar to 90 x 10 super(6) t yr super(-1) or twice the flux of riverine POC from the major rivers of North America, South America, and Africa combined. While such a calculation must be considered illustrative only, the similar tectonic, geomorphologic, and climatic features of the islands of Oceania suggest that the calculation is unlikely to be grossly in error and that the rivers of Oceania therefore represent a major but poorly documented source of sediment and organic carbon to the global ocean.
AN: 3855878
113 of 1521
TI: Role of riverine mangrove forests in organic carbon export to the tropical coastal ocean: A preliminary mass balance for the Fly Delta (Papua New Guinea)
AU: Robertson,-A.I.; Alongi,-D.M.
AF: Australian Inst. Mar. Sci., PMB No. 3, Townsville M.C., Qld. 4810, Australia
SO: GEO-MAR.-LETT. 1995 vol. 15, no. 3-4, pp. 134-139
NT: Special issue: Tropical coastal sedimentary environments.
LA: English
ER: M (Marine); F (Freshwater)
AB: A preliminary mass balance for organic carbon in the Fly Delta was constructed to determine the quantity and source of organic matter exported to the adjacent Gulf of Papua and Coral Sea. Total organic carbon input from the river to the delta is 1.7 x 10 super(12) g C yr super(-1), composed almost equally of DOC and POC. Benthic and pelagic respiration in the delta accounts for 1.0 x 10 super(12) g C yr super(-1), being a major sink for riverine organic carbon. Benthic flux measurements indicate that one third of all DOC entering the delta is taken up by sediments there. Mangrove forests export >3.0 x 10 super(11) g C yr super(-1) POC to delta waters, and it appears that this mangrove carbon is exported to the adjacent shelf and deep sea. These results imply that little of the riverine supply of organic carbon reaches the Gulf of Papua, but that mangrove forests in the Fly and other rivers lining the gulf play a major role in river-shelf carbon exchange.
AN: 3855803
114 of 1521
TI: Third Annual Walker Branch Watershed Research Symposium. Program and abstracts
CA: Oak Ridge Natl. Lab., TN (USA)
SO: 1992 53 pp
NT: NTIS Order No: DE92010786/GAR.
RN: CONF-920389-ABST (CONF920389ABST)
LA: English
ER: F (Freshwater)
AB: The methods and concepts of watershed research, originally applied in an experimental or monitoring mode to relatively small catchments, are increasingly being used at larger scales and for specific applied problems. Research at Oak Ridge National Laboratory, the Tennessee Valley Authority, the US Forest Service, and other agencies and institutions participating in this symposium reflects research over a broad range of spatial scales that is being integrated through large-scale experiments along with computer modeling and graphical interfaces. These research projects address the basic atmospheric, geophysical, biogeochemical, and biological processes that regulate the responses of forested ecosystems to natural environmental variation and anthropogenic stresses. Regional and global issues addressed by presentations include emissions of carbon dioxide, methane, and other hydrocarbons; deposition of sulfate, nitrate, and mercury; land-use changes; biological diversity; droughts; and water quality. The reports presented in this symposium illustrate a wide range of methods and approaches and focus more on concepts and techniques than on a specific physical site. Sites and projects that have contributed research results to this symposium include Walker Branch Watershed (DOE), the Coweeta Hydrologic Laboratory and LTER site (USFS and NSF), Great Smoky Mountains National Park (research funded by NPS, TVA, and EPRI), Imnavait Creek, Alaska (DOE), the TVA-Norris Whole-tree Facility (TVA and EPRI), and DOE's Biomass Program. (DBO)
AN: 3855557
115 of 1521
TI: Regional scale dynamical modelling of biogeochemical processes
AU: Robinson,-A.R.; McKay,-G.
CA: Harvard Univ., Cambridge, MA (USA). Div. of Applied Sciences
SO: 1990 31 pp
NT: NTIS Order No: AD-A240 115/6/GAR.
LA: English
ER: M (Marine)
AB: This project involved the design and development of 3D regional biogeochemical models. The biogeochemical models were designed for attachment to the Harvard Hierarchy of models, including the surface boundary layer (SBL) component of the open ocean baroclinic eddy resolving quasigeostrophic (QG) model, or its coastal extensions, and the open boundary primitive equation (PE) model with hybrid vertical coordinates. Selection of these physical models is motivated by the interest to study the time evolution of biogeochemical components with realistic physical fields, as they all have data assimilation schemes associated. The approach taken in this model design was first to construct simplified models with a minimal number of biogeochemical components, and then step-by-step to introduce further components and detailed intercomponent interactions. These simplifications allow focused research on important biological mechanisms in the presence of realistic physical fields. Construction of regional biogeochemical models with data assimilation schemes will provide a unique tool to determine processes and sensitivities operative in the real ocean and to facilitate efficient experimental design and model validation. The simplest biogeochemical model of interest is of the nitrogen cycle. During this contract we constructed two models with two different compartmentalizations of the nitrogen components. (DBO)
AN: 3855552
116 of 1521
TI: Redfield ratios along isopycnal surfaces -- a complementary study
AU: Minster,-J.-F.; Boulahdid,-M.
AF: UM 39 - CNES/GRGS, 18, Ave. Edouard Belin, 31055 Toulouse Cedex, France
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1987 vol. 34, no. 12, pp. 1981-2003
LA: English
ER: M (Marine)
AB: The recent suggestion by Takahashi et al. to change the Redfield ratios from P/N/-O sub(2) = 1/18/138 to 1/17/172 is critically examined. As a complementary analysis we process the GEOSECS and TTO data in the Atlantic and Indian oceans along four isopycnal horizons. This is done separately for each basin in order to diminish the possible effects of diapycnal mixing. The occurrence of two or three end-member mixing is assessed through "NO" vs salinity plots. End-members are selected among stations at the geographical border of the basins. The Redfield ratios are calculated in a two or three end-member mixing and consumption model via a direct non-linear least-squares technique. The N/-O sub(2) Redfield ratio appears constant and equal to 9.1 plus or minus 0.4. For P/-O sub(2), we confirm the Takahashi et al. value for sigma sub( theta ) = 27.0 and 27.2ppt. For sigma sub( theta ) = 27.4ppt, we find a ratio of 1/141 and for sigma sub( theta ) = 27.8ppt, a value of 1/115. This change is related to the nitrate to phosphate ratio. These results suggest that phosphorus is less easily remobilized, or more strongly recycled in shallow levels, than nitrogen. (DBO)
AN: 3855422
117 of 1521
TI: Hydrogen cycling in the waters near Bermuda: The role of the nitrogen fixer, Oscillatoria thiebautii
AU: Scranton,-M.I.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11794, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1984 vol. 31, no. 2, pp. 133-143
LA: English
ER: M (Marine)
AB: Oceanic surface waters are frequently supersaturated with hydrogen gas relative to atmospheric equilibrium. One possible source for the excess hydrogen is production by nitrogen-fixing organisms, many of which are known to reduce hydrogen ion, H super(+), to H sub(2). Results from short-term, shore-based incubations in Bermuda have demonstrated that Oscillatoria thiebautii, a marine cyanobacterium, produces hydrogen in significant quantities, confirming previous work from St. Croix. Measurement of an acetylene reduction: super(15)N sub(2) fixation ratio of 2.85 plus or minus 0.36:1 for Oscillatoria thiebautii near Bermuda was in agreement with our relatively low rates of hydrogen production (0.002 to 0.05 nmol per colony per hour) compared with nitrogen fixation rates (0.3 to 1.5 nmol per colony per hour). Although hydrogen production was slow, rates would be sufficient to produce surface supersaturations if no removal mechanisms were important. However, data on water column distributions indicated that surface waters near Bermuda at the time of our experiment were undersaturated with hydrogen. Diffusion of hydrogen into the thermocline and in situ biological consumption appear to be the most likely hydrogen sinks. (DBO)
AN: 3855380
118 of 1521
TI: Scavenging residence times of trace metals and surface chemistry of sinking particles in the deep ocean
AU: Balistrieri,-L.; Brewer,-P.G.; Murray,-J.W.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1981 vol. 28, no. 2, pp. 101-121
LA: English
ER: M (Marine)
AB: The adsorption properties of sinking particulate matter in the deep subtropical Atlantic Ocean are modeled by combining the field observations of trace metal scavenging with theoretical surface chemistry. The treatment yields equilibrium constants that define metal interactions with deep-ocean particles. These equilibrium constants can be compared with those that define metal interactions with typical metal oxides and organic compounds. The comparison indicates that metal-particulate matter interactions closely resemble the interactions between organic compounds and metals. Therefore, it is suggested that the adsorption properties of marine particulate matter are controlled by organic coatings. In addition, quantifying the surface properties of deep-ocean particles provides a mean for estimating the scavenging residence times for metals for which the determination has not yet been made. (DBO)
AN: 3855347
119 of 1521
TI: Some aspects of the oxygen-deficient conditions and denitrification in the Arabian Sea
AU: Naqvi,-S.W.A.
AF: Natl. Inst. Oceanogr., Dona Paula, GOA 403 004, India
SO: J.-MAR.-RES. 1987 vol. 45, no. 4, pp. 1049-1072
LA: English
ER: M (Marine)
AB: Utilizing a fairly large amount of recently collected data, some outstanding questions concerning the Arabian Sea denitrification problem are addressed. The true levels of dissolved oxygen, determined colorimetrically, are about an order of magnitude lower than those reported previously from the oxygen minimum zone. Lateral advection of waters from south into the oxygen-deficient layer is suggested by the presence of an intermediate oxygen maximum discernible even at very low oxygen levels. an unusual minimum in nitrate and a corresponding maximum in nitrite are observed occasionally within the depth range 700-1,200 m at several stations, generally located in the northeastern Arabian Sea. These features probably represent the development of a deeper denitrifying layer, in addition to the main denitrifying layer invariably found in the northern Arabian Sea at shallower depths. The deeper layer appears to be related to an increase in particulate organic carbon, probably resulting from seasonal changes in primary production, lateral advection of waters from the slope region off the Indian coast, or an in-situ production of organic matter. (DBO)
AN: 3855103
120 of 1521
TI: A model for the dynamics of nutrients and oxygen in the Baltic Proper
AU: Stigebrandt,-A.; Wulff,-F.
AF: Dep. Oceanogr., Univ. Gothenburg, Box 4038, S-400 40 Gothenburg, Sweden
SO: J.-MAR.-RES. 1987 vol. 45, no. 3, pp. 729-759
LA: English
ER: M (Marine)
AB: A horizontally integrated, time-dependent physical-biogeochemical model of high vertical resolution has been developed for the Baltic Sea proper. A seasonal pycnocline model computes the physical state of the mixed surface layer. Below this is an advective-diffusive model. The vertical advection is caused by a time-dependent, entraining bottom current which transports dense seawater into the system. The vertical distributions of volumes and sediment areas are accounted for by the use of the hypsographic function of the system. The chemical/biological processes controlling the distributions of nitrogen and oxygen are modelled as follows: Primary production is controlled by light, temperature, nutrients and density stratification (critical depth). Nutrient recycling, nitrification and sedimentation are accounted for using simple, rather general process descriptions. Organic matter is broken down both in the water column and at the bottom. Denitrification in the water and sediment is controlled by the concentrations of oxygen, nitrate and organic substrate and by temperature. Sulphate reduction to hydrogen sulphide occurs during anaerobic conditions once nitrate has been depleted. The daily meteorological forcing of the model is synthetic and randomly selected from monthly statistical distributions of observed weather components. The dense water inflow from the sea used in the model is synthetic as well. Loadings of biologically active nitrogen compounds from rivers and atmospheric fall-out, representative of contemporary conditions, are used. (DBO)
AN: 3855092
121 of 1521
TI: The role of bacteria in the turnover of organic carbon in deep-sea sediments
AU: Rowe,-G.T.; Deming,-J.W.
AF: Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: J.-MAR.-RES. 1985 vol. 43, no. 4, pp. 925-950
LA: English
ER: M (Marine)
AB: The cycling of organic carbon in the deep sea was inferred from measurements of sediment trap and box core samples taken on the Biscay and Demerara abyssal plains of the North Atlantic. Of the input of organic carbon to the bottom, less than 10% was buried, i.e., not , consumed biologically. Based on laboratory measurements of bacterial activity in the sediment samples, incubated under in situ temperature and pressure, it was possible to attribute at least 13 to 30% of the total inferred biological consumption of organic carbon to microbial utilization. The complementarity of results from these biochemical and microbiological measurements implies that the decompression of cold abyssal samples during retrieval efforts does not prevent meaningful experiments on the microbial inhabitants, once returned to in situ pressure. (DBO)
AN: 3855073
122 of 1521
TI: Annual cycles of nutrients and chlorophyll in Narragansett Bay, Rhode Island
AU: Pilson,-M.E.Q.
AF: Grad. Sch. Oceanogr., Univ. Rhode Island, Narragansett, RI 02882, USA
SO: J.-MAR.-RES. 1985 vol. 43, no. 4, pp. 849-873
LA: English
ER: M (Marine); B (Brackish)
AB: Nutrient concentrations in Narragansett Bay change in a regular way through the seasons, so that characteristic and well defined cycles are observed, but are different for each nutrient. The cyclic changes are not explainable by processes in the water column alone, nor by advection, even through the replacement time of water in the bay is only 10-40 days. It appears possible to incorporate much of the cycling activity in 13-m super(3) microcosms, so these must include the dominating features of the complex biogeochemical processes involved. Observations in the microcosms suggest that the processes maintaining the annual cycles are sufficiently strong that, in the absence of deliberate experimental manipulation, the cycles might continue not significantly altered through at least one year. Therefore, the nutrient cycles in the bay can be driven largely by activities internal to the bay, especially sediment-water exchanges. (DBO)
AN: 3855069
123 of 1521
TI: Some physical factors affecting ecosystems
AU: Klein,-P.; Steele,-J.H.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: J.-MAR.-RES. 1985 vol. 43, no. 2, pp. 337-350
LA: English
ER: M (Marine)
AB: The response of a simple pelagic ecosystem is investigated in a domain with zero, one- and two-dimensional descriptions of the physical processes. Assuming complete mixing, internal recycling and external exchange of nutrients and their biological products are not additive in terms of the rate of primary production. In a one-dimensional system, advection without diffusion leads to low values of primary production. With two horizontal dimensions, cross diffusion at the boundary gives higher values of production. The consequences for higher trophic levels are described. (DBO)
AN: 3855048
124 of 1521
TI: Rates of recycling of biogenic components of settling particles in the ocean derived from sediment trap experiments
AU: Walsh,-I.; Dymond,-J.; Collier,-R.
AF: Dep. Oceanogr., Texas A&M Univ., Coll. Stn., TX 77843, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1988 vol. 35, no. 1, pp. 43-58
LA: English
ER: M (Marine)
AB: The rates of recycling of the major components of the biologically produced particulate flux (organic carbon, calcium carbonate, and opal) were measured at three sites in the North Equatorial Pacific. The measured biogenic fluxes in sediment traps were normalized to the particulate aluminum flux, and reaction rate constants were derived assuming first order processes occurring during particle settling between adjacent pairs of sediment traps. Mid-water flux maxima were found at each site. Assuming a particle settling rate of 100 m/day, organic carbon, calcium carbonate and opal rate constants below the mid-water flux maxima were 3.7-13/y, 2.3-4.5/y, and 1.0-7.9/y, respectively. Ranges for rate constants above the mid-water flux maxima were 15-32/y for organic carbon, 11-20 y super(-1) for calcium carbonate, and 6.4-27/y for opal. (DBO)
AN: 3854972
125 of 1521
TI: Variations in nitrogen isotopic composition between sinking and suspended particles: Implications for nitrogen cycling and particle transformation in the open ocean
AU: Altabet,-M.A.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1988 vol. 35, no. 4, pp. 535-554
LA: English
ER: M (Marine)
AB: Significant and consistent differences in nitrogen isotopic ratio (measured as delta super(15)N relative to atmospheric N sub(2)) are observed between suspended and sinking particles in the Sargasso Sea. Suspended particles in the euphotic zone have an annual average of -0.2ppt while particles sinking out of the euphotic zone average 3.7ppt. This latter value is equivalent to the average delta super(15)N value for the sources of new nitrogen to the euphotic zone. The delta super(15)N of NO sub(3) super(-) below the euphotic zone is similar, confirming that this is the major source. The downward particle flux acts to preferentially export super(15)N out of the euphotic zone, with the result that suspended particles are depleted in super(15)N relative to new nitrogen sources. The observed difference in delta super(15)N is evidence that the net transformation of suspended into sinking particles in this region is a result of active processes such as macrozooplankton feeding, as opposed to passive physical effects. Suspended particles below 200 m are 6ppt higher in delta super(15)N relative to those within the euphotic zone. This observation reflects, in part, the origin of suspended particles below the euphotic zone from the larger, faster sinking particles which are enriched in delta super(15)N. Since these suspended particles are also higher in delta super(15)N relative to sinking particles by 3ppt, isotopic fractionation must occur during the disaggregation of sinking particles and/or the subsequent degradation of suspended particles. (DBO)
AN: 3854960
126 of 1521
TI: Re-evaluation of the nutrient exchanges in the Strait of Gibraltar
AU: Coste,-B.; Le-Corre,-P.; Minas,-H.J.
AF: Cent. d'Oceaonologie de Marseille, Faculte des Sci. de Luminy, Case 901, 13288 Marseille Cedex 9, France
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1988 vol. 35, no. 5, pp. 767-775
LA: English
ER: M (Marine)
AB: New data of inorganic, particulate and dissolved organic forms of nitrogen, phosphorus and silicon from the Mediterranean Sea near the Strait of Gibraltar allow an estimate of the exchanges of these elements between the Mediterranean Sea and the Atlantic Ocean. Input by Atlantic waters is lower than output by the Mediterranean waters. The difference accounts for about 10% of the total nitrogen and phosphorus outflow and for about 50% of the total silicon outflow. The deficit appears to be balanced by the nutrient supply from land drainage. The dissolved organic nitrogen and phosphorus are about 50% of the total nitrogen and phosphorus inflow and less than 30% of the outflow. The Mediterranean Sea appears to be an active basin of mineralization. (DBO)
AN: 3854938
127 of 1521
TI: Phosphatases revisited: Analysis of particle-associated enzyme activities in aquatic systems
AU: Berman,-T.; Wynne,-D.; Kaplan,-B.
AF: Kinneret Limnol. Lab., Israel Oceanogr. and Limnol. Res, P.O. Box 345, Tiberias 14102, Israel
CO: Conf. on Limnology and Oceanography, , 26-29 Jun 1989
SO: FLUXES-BETWEEN-TROPHIC-LEVELS-AND-THROUGH-THE-WATER-SEDIMENT-INTERFACE. Bonin,-D.J.;Golterman,-H.L.-eds. 1990 vol. 207 pp. 287-294
ST: HYDROBIOLOGIA vol. 207
LA: English
ER: F (Freshwater)
AB: A modified assay for alkaline or acid phosphatases associated with microorganisms in aquatic environments has been developed. This is based on collecting microplankton on filters and subsequently determining the enzyme activities spectrophotometrically or fluorometrically, using p-nitrophenyl-phosphate or 4-methylumbelliferyl phosphate, respectively as substrates. The assay is simple and rapid, and has the further advantage of permitting phosphatase activities to be assigned to specific size fractions of the natural microplankton. In samples taken from Lake Kinneret and a nearby reservoir, a consistently high proportion of the total alkaline or acid phosphatase activity was associated with the size fraction <0.8 mu m >0.2 mu m indicating the potentially high contribution of bacteria to these activities. This approach can also be used to examine the enzymatic potential of microplankton to release orthophosphate from other organo-phosphate substrates. (DBO)
AN: 3854916
128 of 1521
TI: Incidence of mussel culture on biogeochemical fluxes at the sediment-water interface
AU: Baudinet,-D.; Alliot,-E.; Berland,-B.; Grenz,-C.; Plante-Cuny,-M.-R.; Plante,-R.; Salen-Picard,-C.
AF: Cent. Oceanol. Marseille, Stn. Mar. Endoume, 13007 Marseille, France
CO: Conf. on Limnology and Oceanography, , 26-29 Jun 1989
SO: FLUXES-BETWEEN-TROPHIC-LEVELS-AND-THROUGH-THE-WATER-SEDIMENT-INTERFACE. Bonin,-D.J.;Golterman,-H.L.-eds. 1990 vol. 207 pp. 187-196
ST: HYDROBIOLOGIA vol. 207
LA: English
ER: M (Marine)
AB: Upward nutrient fluxes at the sediment-water interface were studied in a mussel farming zone (Carteau, Gulf of Fos, France) in order to estimate the impact of organic matter input from biodeposition. Nitrate, nitrite, ammonia, silicate, phosphate and oxygen were measured. Fluxes were estimated by means of polyacrylate benthic chambers placed at sites located under (UM) and outside (OM) the rope hanging structures. Transformation of biodeposited organic matter increases phosphate, silicate and ammonia fluxes. No variation in nitrite fluxes could be detected and only minor differences were observed in nitrate and the oxygen production/consumption equilibrium at the two stations. Phosphate and silicate fluxes, which were always higher at the UM than at the OM site, decreased from spring to winter. Ammonia fluxes were very high under mussel cultures in May and September and lower in November. The fact that ammonia flux was always higher at the UM than at the OM sites might be explained by degradation of mussel biodeposit, as well as by benthic macrafauna excretion. Discrepancies between fluxes of the nutrients studied at the UM and OM sites increased as organic particulate matter in the water column decreased. Variations of oxygen flux followed a different pattern, since they were correlated with presence and abundance of photosynthetic microphytes on the bottom and in the water. Bottom respiration exceeded production of oxygen only in May 1988 at the UM station. As it now stands, biodeposit input into the sediment under mussel ropes does not affect the ecosystem, although the flow of nutrients towards the water column is higher than in other areas (DBO).
AN: 3854905
129 of 1521
TI: In situ biochemical and bacterial variation of sediments enriched with mussel biodeposits
AU: Grenz,-C.; Hermin,-M.-N.; Baudinet,-D.; Daumas,-R.
AF: Cent. Oceanol. Marseille, Stn. Mar. Endoume, 13007 Marseille, France
CO: Conf. on Limnology and Oceanography, , 26-29 Jun 1989
SO: FLUXES-BETWEEN-TROPHIC-LEVELS-AND-THROUGH-THE-WATER-SEDIMENT-INTERFACE. Bonin,-D.J.;Golterman,-H.L.-eds. 1990 vol. 207 pp. 153-160
ST: HYDROBIOLOGIA vol. 207
LA: English
ER: M (Marine)
AB: In order to estimate the qualitative variation of sedimented mussel deposits, biochemical and microbial measurements were undertaken after a sediment enrichment with fresh faeces and pseudo-faeces collected in a mussel farming area (Carteau, Gulf of Fos). During two months, cores sampled were investigated at three stations: a first station enriched with mussel deposits, a second considered as a reference station without mussel deposits and occasionally a third corresponding to a continuously enriched sediment under a rope culture. Carbohydrate, organic carbon and nitrogen contents in the sediments gave evidence of a short term variation after sedimentation. Bacterial production increased rapidly at the enriched station and returned to its initial level 8 days later. At this station, exoglucosidasic activity of bacteria, low at the beginning, presented a maximum two weeks after enrichment whereas exoproteolytic activity, which was high in the biodeposits, decreased in the course of the first week. These exoenzymatic activities were significantly higher at the enriched station than at the reference stations. Carbohydrate measurements were in agreement with these results. Degradation rate of biodeposits is discussed on the basis of exoenzymatic activity, organic carbon, nitrogen and free amino acid content at the three stations (DBO).
AN: 3854901
130 of 1521
TI: Study of the Ria Formosa ecosystem: Benthic nutrient remineralization and tidal variability of nutrients in the water
AU: Falcao,-M.; Vale,-C.
AF: Inst. Nac. Invest. Pescas, Cent. Reg. Invest. Pesq., Av. 5 de Outubro, 8700 Olhao, Portugal
CO: Conf. on Limnology and Oceanography, , 26-29 Jun 1989
SO: FLUXES-BETWEEN-TROPHIC-LEVELS-AND-THROUGH-THE-WATER-SEDIMENT-INTERFACE. Bonin,-D.J.;Golterman,-H.L.-eds. 1990 vol. 207 pp. 137-146
ST: HYDROBIOLOGIA vol. 207
LA: English
ER: M (Marine)
AB: Exchange of nutrients across the sediment-water interfaces of Ria Formosa was studied in the laboratory. In the field, water samples were collected (i) fortnightly, at low and high tide over one year, and (ii) semi-diurnally, over three neap-spring tidal cycles in winter. Results from both laboratory experiments and field collection were quite variable. Higher liberation rates of silicates, phosphates and ammonium occurred in chambers whose bottom was formed by mixtures of mud and sand covered by vegetation with clams. The bottom took up nitrates from the overlying water. Nutrient variations in the lagoon water were controlled both seasonally and tidally. Higher concentrations of silicates were found at low tide independently of the season; phosphates in spring/summer at low tide; nitrates in winter/spring at high tide. Tidal flushing appears to be an important removal-mechanism in this lagoon. (DBO)
AN: 3854899
131 of 1521
TI: Decrease in allochthonous organic inputs in dark submarine caves, connection with lowering in benthic community richness
AU: Fichez,-R.
AF: Sch. Environ. Sci., Univ. East Anglia, NR4 7TJ Norwich, UK
CO: Conf. on Limnology and Oceanography, , 26-29 Jun 1989
SO: FLUXES-BETWEEN-TROPHIC-LEVELS-AND-THROUGH-THE-WATER-SEDIMENT-INTERFACE. Bonin,-D.J.;Golterman,-H.L.-eds. 1990 vol. 207 pp. 61-69
ST: HYDROBIOLOGIA vol. 207
LA: English
ER: M (Marine)
AB: Ten sediment trap arrays were deployed over two years for periods of 3 to 40 days in three different sampling points along a 50 m long Mediterranean submarine cave. Mean total particulate matter flux decreased strongly from the semi-dark area (3.3 g m super(-2)/d) to the dark area (0.8 and 0.6 g m super(-2)/d). Carbon represented 3.3% to 3.5% and nitrogen 0.34% to 0.38% of settling dry matter. The decrease in organic input from the entrance to the terminal part of the cave results in increasingly oligotrophic conditions with distance from the cave entrance. Horizontal resource limitation can be connected with a strong zonal decrease in fauna richness. Biomass declines both in hard substrate and soft bottom communities. Despite major differences, some similarities are noticed between oligotrophic conditions that may occur in the dark cave and those in around 1000 m depth ecosystems. Dark oligotrophic submarine caves can be considered to be good scale models for the study of some aspects of general trophic pathways. (DBO)
AN: 3854844
132 of 1521
TI: Contribution of the water-sediment interface to the transformation of biogenic substances: Application to nitrogen compounds
AU: Daumas,-R.
AF: CNRS, Microbiol. Mar., Fac. Sci. Luminy, Case 907, 13288 Marseille Cedex 9, France
CO: Conf. on Limnology and Oceanography, , 26-29 Jun 1989
SO: FLUXES-BETWEEN-TROPHIC-LEVELS-AND-THROUGH-THE-WATER-SEDIMENT-INTERFACE. Bonin,-D.J.;Golterman,-H.L.-eds. 1990 vol. 207 pp. 15-29
ST: HYDROBIOLOGIA vol. 207
LA: English
ER: M (Marine); F (Freshwater)
AB: Up to now the water-sediment interface (WSI) has not been considered by limnologists and oceanographers as a theoretical frontier between two phases, but as a variable layer comprising the overlying bottom water, the superficial sediment, and the bioturbed sediment. This heterogeneous benthic boundary layer forms a non-equilibrated assemblage of an aqueous phase, a mineral phase influencing the exchanges, and a dissolved gaseous phase regulating biological activity, detrital organic matter present as dissolved or adsorbed compounds and particles, and a living benthic community dominated by microorganisms. Biological activity and the equilibrium between these components are linked to depth, bottom currents, primary production and allochtonous inputs of organic matter. The settling rate of particulate matter in the water column, which depends on both the size and density of particles, is also an important factor. Settled organic matter is broken down mainly by heterotrophic microorganisms. In the first stage, dissolved or particulate matter is depolymerized by exoenzymes linked to the bacterial membrane. Other heterotrophic organisms, like flagellates and ciliates, contribute to the activity of bacterial populations or to a modification of the physical and chemical characteristics of organic matter like macrofauna. Bacterial activity in the WSI is one to two orders of magnitude higher than in overlying bottom water, depending on the density of the bacterial population, on the amount of available organic matter, and on the presence of predators grazing on bacteria and macrofauna and increasing oxygen and dissolved substrates. The WSI is now considered as a sink for particulate matter and biopolymers, and/or as a sink or source for organic monomers and NH sub(4) super(+) depending on their concentrations. As a result of its contribution to mineral and organic cycles, the WSI is a crossroad for exchanges between aqueous and sediment layer. During the last decade, intensive work has been performed in this field, but progress has been slow due to the heterogeneity of the layer and the adsorptive properties of the mineral fraction. (DBO)
AN: 3854839
133 of 1521
TI: Nutrient dynamics and pelagic food web interactions in oligotrophic and eutrophic environments: An overview
AU: Capblancq,-J.
AF: Lab. Hydrobiol., Univ. Toulouse III, 118 Route de Narbonne, 31062 Toulouse Cedex, France
CO: Conf. on Limnology and Oceanography, , 26-29 Jun 1989
SO: FLUXES-BETWEEN-TROPHIC-LEVELS-AND-THROUGH-THE-WATER-SEDIMENT-INTERFACE. Bonin,-D.J.;Golterman,-H.L.-eds. 1990 vol. 207 pp. 1-14
ST: HYDROBIOLOGIA vol. 207
LA: English
ER: F (Freshwater)
AB: The concept of limiting nutrients is a cornerstone of theories concerning the control of production, structure and dynamics of freshwater and marine plankton. The current dogma is that nitrogen is limiting in most marine environments while freshwater ecosystems are mostly phosphorus-limited, although evidence of phytoplankton limitation by either N or P has been found in both environments. However, the same considerations apply to the availability of phosphorus in freshwater as to nitrogen in oceans. In resource-limited environments the plankton dynamics depend mostly on the internal mechanisms which act to recycle the limiting nutrient many times over within the surface waters. As the overall productivity increases, this dependence on nutrient regeneration decreases. The relationship between the stock of limiting nutrient, rates of supply and plankton dynamics must therefore be seen in the light of the processes operating within the entire food chain over quite different time scales. There is strong evidence that process-rates are mostly size-dependent and that food web interactions at the microbial level (picophytoplankton, bacteria, microheterotrophs) strongly affect the production of carbon and the regeneration of nutrients in the pelagic zone. (DBO)
AN: 3854838
134 of 1521
TI: Seasonal cycling of putrescine and amino acids in relation to biological production in a stratified coastal salt pond
AU: Lee,-C.; Joergensen,-N.O.G.
AF: Mar. Sci. Res. Cent., SUNY Stony Brook, Stony Brook, NY 11794-5000, USA
SO: BIOGEOCHEMISTRY 1995 vol. 29, no. 2, pp. 131-157
LA: English
ER: B (Brackish)
AB: Seasonal cycles of concentrations and microbial uptake of dissolved free amino acids and the polyamine, putrescine, were followed during summer stratification of a coastal salt pond. Stratification began in May and was clearly seen in profiles of temperature, salinity, pH and alkalinity. Primary production exhibited a mid-August maximum and the O sub(2)-H sub(2)S interface shoaled at that time. POC and phytopigments roughly followed the pattern of primary production. Cycling of putresince, like the amino acids, was strongly influenced by primary production and microbial decomposition. Putrescine concentration profiles appeared to follow the pattern of primary production more closely, while amino acids appeared to follow the pattern of microbial production. The absence of production of putrescine during the decomposition of dissolved ornithine and the correlation of putrescine concentration with primary production suggest a direct source from algae in the water column. Microbial uptake of amino acids and putrescine together accounted for 60-90% of the bacterial C production measured in oxic waters and almost 300% of that measured in the anoxic bottom layer. Since other organic carbon and nitrogen compounds are also being taken up, these data suggest that tracer uptake methods as we used them may overestimate the true microbial uptake rates, or release of other organic compounds by microbes occurs at the same time. Further work on carbon and nitrogen budgets is needed to resolve the apparent imbalance between organic C and N incorporation and bacterial production.
AN: 3852984
135 of 1521
TI: Metabolism of volatile sulfur compounds in Lake Ciso
AU: Simo,-R.; De-Wit,-R.; Villanueva,-J.; Grimalt,-J.
CO: 25. Congress in Barcelona, Barcelona (Spain), 21-27 Aug 1992
SO: CONGRESS-IN-BARCELONA-1992.-PROCEEDINGS. Sladeckova,-A.-ed. STUTTGART-FRG SCHWEIZERBART'-SCHE-VERLAGSBUCHHANDLUNG 1994 vol. 25, no. 2 pp. 743-746
ST: VERH.-INT.-VER.-THEOR.-ANGEW.-LIMNOL.-PROC.-INT.-ASSOC.-THEOR.-APPL.-LIMNOL.-TRAV.-ASSOC.-INT.-LIMNOL.-THEOR.-APPL. vol. 25, no. 2
LA: English
ER: F (Freshwater)
AN: 3851307
136 of 1521
TI: Improved construction, parametrization and interpretation of steady-state ecosystem models
AU: Pauly,-D.; Soriano-Bartz,-M.L.; Palomares,-M.L.D.
AF: ICLARM, MC P.O.B. 2631, Makati City 0718, Philippines
CA: International Cent. for Living Aquatic Resources Management, Manila (Philippines)
CO: ICES Theme Session on Trophic Models of Aquatic Ecosystems, Copenhagen (Denmark), Oct 1990
SO: TROPHIC-MODELS-OF-AQUATIC-ECOSYSTEMS. Christensen,-V.;Pauly,-D.-eds. MANILA-PHILIPPINES ICLARM 1993 no. 26 pp. 1-13
ST: ICLARM-CONF.-PROC. no. 26
LA: English
ER: M (Marine); F (Freshwater)
AB: An improved version of J.J. Polovina's ECOPATH program for the construction of steady-state multispecies ecosystem models from fisheries data is presented. This new version called "ECOPATH II", differs from the original, aside from being more user-friendly, in a number of important features, among othes: (1) use of a "generalized inverse" matrix routine allowing the system of linear equations used to estimate model parameters to be over- or slightly underdetermined; (2) estimation of (almost) any set of unknowns and not only of biomasses; (3) explicit consideration of respiratory, egestive and excretory losses (with defaults provided for inputs) and of the detritus pathways; (4) estimation of numerous derived quantities on species group or whole-system basis, such as gross and net efficiencies, trophic levels, food electivity, pathways and cycles involving any group and "ascendency" sensu R.E. Ulanowizc. The preliminary version of an empirical multiple regression model for the estimation from easy to estimate parameters of relative food consumption by fish populations is presented; this model provides reasonable values of the input into ecosystem models that were to date most difficult to estimate. An application to the coral reef ecosystem of French Frigate Shoals (Hawaii) is presented, along with some suggestions as to how this methodology could be applied to Kuwait waters.
AN: 3851122
137 of 1521
TI: Processes controlling chemical distributions in the Firth of Clyde (Scotland)
AU: Muller,-F.L.L.; Balls,-P.W.; Tranter,-M.
AF: Dept. of Oceanography, The University of Southampton, Southampton Oceanography Centre, Southampton SO14 3ZH, UK
SO: OCEANOL.-ACTA 1995 vol. 18, no. 5, pp. 493-510
LA: English
ER: M (Marine)
AB: A total of 28 chemical variables were measured on water samples taken on an approximately longitudinal section of the Firth of Clyde in August 1989, November 1989, March 1990, July 1990 and March 1991. The data were integrated in a study of the overall processes acting on these variables. The sampling section crossed two mixing zoness i.e. the Clyde Estuary Plume (30 < S < 32) and the Clyde Sea (32 < S < 34), with mixing times of 4-25 days and 60-150 days respectively. The interpretation of the distributional data was complicated in July 1990 by the penetration of an "older" water mass originating from one of the five sealochs bordering the Firth of Clyde. Heterogeneous reactions within the Clyde Estuary Plume generally modified the export fluxes of dissolved trace metals to the Clyde Sea in the order: Fe, Pb > Mn, Co > Zn, Cd, Cu, Ni. In the deep layers of the sealochs, dissolved Pb was scavenged by newly formed hydrous Mn oxides following Mn(II) diffusion from the underlying sediments. Resuspension of bottom sediments was a permanent feature of the inner Firth, although it did not significantly affect the solid-solution partitioning of trace metals. Organic matter decomposition promoted a tight inverse relationship between O sub(2)-% and pCO sub(2) in the deep layers (especially in November 1989 and July 1990), as did photosynthetic activity in the surface layers in July 1990. The latter process also manifested itself in the surface depletion of dissolved PO sub(4), NO sub(3). Si, ECO sub(2), Fe, Zn and Cd. A ratio P:N:Si:C of 1:9:6:68 was obtained in relation to the uptake of these elements by phytoplankton. Gas exchange at the air-sea interface - coupled with turbulent vertical mixing - was the main process controlling O sub(2) and CO sub(2) concentrations in the surface layers in March 1990 and 1991. At wind speeds below 8 m s super(-1), i.e. in the absence of bubble-induced gas exchange. O sub(2) reached saturation in the outer Firth but pCO2 remained above its atmospheric equilibrium value of 350 ppm. At wind speeds above 12 m s super(-1) (March 1990) pCO sub(2) was close to 350 ppm while O sub(2) became supersaturated. Water composition should be examined not only in relation to that anticipated trom instantaneous mixing between end members but also in relation to the transit times of water masses. An application of this approach suggests that the inner Firth, situated at the triple junction Clyde Estuary-Sealoch System outer Firth, is the area where the rates of heterogeneous reactions are fastest.
AN: 3851058
138 of 1521
TI: Effects of increased solar ultraviolet radiation on biogeochemical cycles
AU: Zepp,-R.G.; Callaghan,-T.V.; Erickson,-D.J.
AF: U.S. EPA, Environ. Res. Lab., 960 College Stn. Rd., Athens, GA 30605-2720, USA
SO: AMBIO 1995 vol. 24, no. 3, pp. 181-187
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical cycles thus altering both sources and sinks of greenhouse and chemically-important trace gases (e.g., carbon dioxide (CO sub(2)), carbon monoxide (CO), carbonyl sulfide (COS)). In terrestrial ecosystems, increased UV-B could modify both the production and decomposition of plant matter with concomitant changes in the uptake and release of atmospherically-important trace gases. Decomposition processes can be accelerated when UV-B photodegrades surface litter, or retarded when the dominant effect involves changes in the chemical composition of living tissues that reduce the biodegradability of buried litter. These changes in decomposition can affect microbial production of carbon dioxide and other trace gases, and also may affect the availability of nutrients essential for plant growth. Primary production can be reduced by enhanced UV-B, but the effect is variable between species and even cultivars of some crops. Likewise, the effects of enhanced UV-B on photoproduction of CO from plant matter is species dependent and occurs more efficiently from dead than living matter. Aquatic ecosystem studies in several different locations have shown that reductions in current levels of solar UV-B result in enhanced primary production, and Antarctic experiments under the ozone hole demonstrated that primary production is inhibited by enhanced UV-B. In addition to its effects on primary production, solar UV radiation can reduce bacterioplankton growth in the upper ocean with potentially important effects on marine biogeochemical cycles. Decomposition processes can be retarded when bacterial activity is suppressed by enhanced UV-B radiation or stimulated when solar UV radiation photodegrades aquatic dissolved organic matter (DOM). Photodegradation of DOM results in loss of UV absorption and formation of dissolved inorganic carbon (DIC), CO, and organic substrates that are readily mineralized or taken up by aquatic microorganisms. The marine sulfur cycle may be affected by UV-B radiation resulting in possible changes in the sea-to-air emissions of COS and dimethylsulfide (DMS), two gases that are degraded to sulfate aerosols in the stratosphere and troposphere, respectively.
AN: 3848713
139 of 1521
TI: Regulation of atmospheric O sub(2): Feedback in the microbial feedbag
AU: Kump,-L.R.; Mackenzie,-F.T.
AF: Dep. Oceanogr., Univ. Hawaii, Honolulu, HI 96822, USA
SO: SCIENCE-WASH. 1996 vol. 271, no. 5248, pp. 459-460
LA: English
ER: M (Marine)
AB: What controls the oxygen content of the atmosphere? This fundamental question has been asked innumerable times in the last several decades without a fully satisfactory answer. From conceptual models (1), increasingly complex numerical models (2) have been created. Given the few-million-year residence time of O sub(2) in the atmosphere, slight imbalances in the biogeochemical cycle of oxygen could have led, over geological time intervals, to large fluctuations in concentration. Catastrophic phenomena sensitive to extremes in oxygen levels, such as global wildfire or the extinction of large animals, would have occurred if O sub(2) concentrations had exceeded 30% (4) or had fallen to less than 10% or so. However, there is no geological evidence of prolonged global wildfires. It appears that there are feedback mechanisms in the natural cycle of O sub(2) operating on land and in the ocean that prevent such large fluctuations from occurring. Van Cappellen and Ingall argue that the important feedback mechanism resides in the ocean and involves the dependence of nutrient recycling rates on the oxygen content of the deep sea. Nitrogen (N) and phosphorus (P) are considered most important. The growth of marine algae involves the incorporation of N and P into living tissue. Ingestion by animals leads to the packaging of this material into relatively dense fecal pellets. Both N and P are preferentially regenerated by microbial degradation processes in the water column and are transported by upwelling waters moving to the surface, where they become available for biological uptake once again.
AN: 3847952
140 of 1521
TI: Seasonal cycling of Fe in saltmarsh sediments
AU: Kostka,-J.E.; Luther,-G.W.,III
AF: Cent. Great Lakes Stud., Univ. Wisconsin-Milwaukee, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA
SO: BIOGEOCHEMISTRY 1995 vol. 29, no. 2, pp. 159-181
LA: English
ER: M (Marine); B (Brackish)
AB: This study combines an analysis of porewater chemistry with new, solid phase wet chemical extractions to examine the seasonal cycling of Fe in vegetated and unvegetated (cyanobacterial mat) saltmarsh sediments. Saltmarsh sediments are shown to contain more solid phase reactive Fe than other marine sediments studied so far. From the partitioning and speciation of solid Fe, and solid/soluble reduced S analysis in 10 sediment cores, we have observed that a majority of solid Fe in these sediments is cycled rapidly and completely between oxidized reactive Fe and reduced Fe as pyrite. Vegetated porewaters showed a lower pH and much higher Fe(II) concentrations on average than unvegetated porewaters in the top 10 cm, whereas sulfate, alkalinity, and sulfide concentrations were similar in the two environments. The amorphous Fe(III) oxide fraction showed a high negative correlation to solid and soluble reduced S (r super(2) = -0.86 and -0.71, respectively) in surface vegetated sediments whereas the crystalline Fe(III) oxide fraction showed a high negative correlation (r super(2) = -0.96) to sulfide only at depth. Though reactive Fe was observed in unvegetated sediments, no seasonal trend was apparent and the speciation of solid Fe revealed that most of it was reduced. Solid phase and porewater chemistry support the dominant role of the biota (Spartina alterniflora and bacteria) in controlling the reactivity of Fe and suggest that the current definition of solid phase, reactive Fe should be expanded to include crystalline Fe(III) minerals which are available for pyrite formation in saltmarsh sediments. In support of previous saltmarsh studies, we present evidence that the redox cycle of solid Fe is controlled by sulfate reduction and sediment oxidation which respond to both annual cycles (light, temperature) and to short-term, episodic effects such as weather and tides.
AN: 3847504
141 of 1521
TI: Biogeochemical controls on aluminum chemistry in the 0 horizon of a red spruce (Picea rubens Sarg.) stand in Central Maine, USA
AU: Rustad,-L.E.; Cronan,-C.S.
AF: Dep. Appl. Ecol. Environ. Sci., Univ. Maine, Orono, ME 04469, USA
SO: BIOGEOCHEMISTRY 1995 vol. 29, no. 2, pp. 107-129
LA: English
ER: F (Freshwater)
AB: This study examined the biotic and abiotic processes controlling solution chemistry and cycling of aluminum (Al) in the organic horizons of a northern coniferous forest ecosystem. A mass balance budget indicated that aboveground inputs of Al to the O horizon averaged 0.9 kg ha super(-1) yr super(-1), with major inputs accounted for by littefall (69%), followed by precipitation (21%), and net canopy throughfall plus stemflow (10%). Estimated leaching losses of Al from the O horizon averaged 2.1 kg Al ha super(-1) yr super(-1). We hypothesize that the difference between measured Al inputs and outputs can be accounted for by Al release from weathering of soil minerals admixed into the O horizon. Variations in O horizon solution Al chemistry were influenced by a number of factors, including pH, Al equilibria with different solid-phase organic exchange sites, and Al complexation with humic ligands in soil solution.
AN: 3847495
142 of 1521
TI: Alkalinity changes in the Sargasso Sea: Geochemical evidence of calcification?
AU: Bates,-N.R.; Michaels,-A.F.; Knap,-A.H.
AF: Bermuda Biological Station For Research Inc., 17 Biological Station Lane, Ferry Reach, GE01, Bermuda
SO: MAR.-CHEM. 1996 vol. 51, no. 4, pp. 347-358
LA: English
AB: Strong seasonal patterns in upper ocean total carbon dioxide (TCO2), alkalinity (TA) and calculated pCO2 were observed in a time series of water column measurements collected at the US Joint Global Ocean Flux Study (JGOFS) BATS site (31 degree 50'N, 64 degree 10'W) in the Sargasso Sea. TA distribution was a conservative function of salinity. However, in February 1992, a non-conservative decrease in TA was observed, with maximumdepletion of 25-30 mu moles kg-1 occuring in the surface layer and at the depth of the chlorophyll maximum ( similar to 80-100 m). Mixed-layer TCO2 also decreased, while surface pCO2 increased by 25-30 mu atm. We suggest these changes in carbon dioxide species resulted from open-ocean calcification by carbonate-secreting organisms rather than physical processes. Coccolithophore calcification is the most likely cause of this event although calcification by foraminifera or pteropods cannot be ruledout. Due to the transient increase in surface pCO2, the net annual transfer of CO2 into the ocean at BATS was reduced. These observations demonstrate the potential importance of open-ocean calcification and biological community structure in the biogeochemical cycling of carbon.
AN: 3846854
143 of 1521
TI: Phosphine from harbor surface sediments
AU: Gassmann,-G.; Schorn,-F.
AF: Biol. Anstalt Helgoland, W-2000 Hamburg, FRG
SO: NATURWISSENSCHAFTEN 1993 vol. 80, no. 2, pp. 78-80
LA: English
ER: M (Marine)
AB: Biogenic phosphine, the volatile constituent of the global biogeochemical phosphorus cycle, was found over sewage plant sludges in 1988. In earlier reports phosphine was found in soil, Black Sea sediments and biological iron corrosion processes. These findings contradict the idea that phosphine could not, as a matter of principle, be formed biologically in nature. This report shows the presence of phosphine in surface sediments of the Hamburg Harbor (Germany).
AN: 3843228
144 of 1521
TI: The dynamics of mire formation in relation to carbon accumulation and climate change.
OT: Soistumisdynamiikka, soiden hiilitase ja ilmaston muutos
AU: Korphola,-A.
AF: Dep. Geogr., Lab. Phys. Geogr., P.O. Box 9 (Siltavuorenpenger 20 A), FIN-00014 Univ. Helsinki, Finland
SO: TERRA 1994 vol. 106, no. 3, pp. 209-215
LA: Finnish
ER: F (Freshwater)
AB: Peatlands in their natural state are net accumulators of organic carbon and thus an important component of the global carbon cycle. Knowledge of general ecosystem dynamics, climatic controls, and rate of long-term peat accumulation are necessary for understanding and modelling the carbon cycle in mire environments. Here the role of different environmental factors in the process of carbon accumulation in peatland ecosystems is discussed. Examination of the formation and dynamics of an entire mire ecosystem, and the role of carbon in it is shown to be essential, instead of just making single-core analyses. Along vertical mire growth, the lateral expansion of mires in different time periods, for example, should be considered when calculating the long-term rates of carbon accumulation.
AN: 3843190
145 of 1521
TI: Spatial and temporal variation of physicochemical parameters in a shallow reservoir seasonally covered by Pistia stratiotes L. in Uruguay
AU: Mazzeo,-N.; Gorga,-J.; Crosa,-D.; Ferrando,-J.; Pintos,-W.
AF: Univ. Concepcion, Dep. Botanica, Casilla 2407. Ap. 10, Concepcion-Chile
SO: J.-FRESHWAT.-ECOL. 1995 vol. 10, no. 2, pp. 141-149
LA: English
ER: F (Freshwater)
AB: Spatial and temporal variation of physicochemical parameters of Cisne Reservoir were studied. A clear spatial pattern was observed between the tributaries and the reservoir, with the highest values of conductivity, alkalinity, pH, silicate and phosphate (SRP) in the tributaries. The incorporation of bicarbonate, silicate, SRP and other nutrients by littoral vegetation and the decomposition process of macrophytes could explain the spatial pattern and the temporal variation of the nutrients. The freshwater marsh situated between the tributaries and reservoir acts as sink for silicate and SRP. The temporal and spatial pattern of total phosphorus was correlated with suspended matter values. The low nitrogen concentration and the ratio of the inorganic nitrogen to SRP suggest that nitrogen is a limiting factor for primary production.
AN: 3843106
146 of 1521
TI: Bioavailable amino acids in sediments: A biomimetic, kinetics-based approach
AU: Mayer,-L.M.; Schick,-L.L.; Sawyer,-T.; Plante,-C.J.
AF: Dep. Oceanogr., Darling Mar. Cent., Univ. Maine, Walpole 04573 ME, USA
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 3, pp. 511-520
LA: English
ER: M (Marine)
AB: We developed a biomimetic approach, based on direct incubation with proteolytic enzymes, to measure bioavailable amino acids in sediments. The kinetics of release of monomers and oligopeptides, which are amenable to absorption by cells, is measured as either individual or total amino acids. Microbial proteases incubated with fresh sediments yield amino acids at a similar rate as gut juices from a deposit-feeding holothuroid. Amino acid release from fresh sediment was dominated by a slow hydrolysis step from a refractory substrate, which can be described with a first-order rate law. Typical rate constants for release were in the range 0.15-0.52/h, consistent with gut residence times of deposit feeders. The bioavailable pool of peptides had a composition resembling that of average biological tissue, but comparisons with tissue composition suggested dietary deficiency of some essential amino acids. The early stages of release exhibited significant contributions from osmolytes (e.g. glutamic acid and taurine), while a larger, more slowly released pool was anomalously low in methionine, suggesting a contribution from microbial coat proteins. Freezing the sediment led to greater yields of amino acids, which reduced the simulation of a deposit feeder's gut but indicated a larger pool of potentially bioavailable substrate protected by some kind of matrix. This larger pool of peptide substrate was usually dominated by higher molecular weight polypeptides as measured by the Coomassie Blue method.
AN: 3843002
147 of 1521
TI: Carbon and nitrogen cycling in intertidal sediments near Doel, Scheldt Estuary
AU: Middelburg,-J.J.; Klaver,-G.; Nieuwenhuize,-J.; Vlug,-T.
AF: Netherlands Inst. Ecol., Cent. Estuar. Coast. Ecol., Vierst. 28, NL-4401 EA Yerseke, Netherlands
SO: HYDROBIOLOGIA 1995 vol. 311, no. 1-3, pp. 57-69
NT: Special Issue: Major Biological Processes in European Tidal Estuaries.
LA: English
ER: B (Brackish)
AB: Carbon and nitrogen cycling in intertidal mud flat sediments in the Scheldt Estuary was studied using measurements of carbon dioxide, methane and nitrous oxide emission rates and pore-water profiles of capital sigma CO sub(2), ammonium and nitrate. A comparison between chamber measured carbon dioxide fluxes and those based on capital sigma CO sub(2) pore-water gradients using Fick's First law indicates that apparent diffusion coefficients are 2 to 28 times higher than bulk sediment diffusion coefficients based on molecular diffusion. Seasonal changes in gaseous carbon fluxes or capital sigma CO sub(2) pore water concentrations cannot be used directly, or in a simple way, to determine seasonal rates of mineralization, because of marked seasonal changes in pore-water storage and exchange parameters. The annual amount of carbon delivered to the sediment is 42 mol/m super(2), of which about 42% becomes buried, the remaining being emitted as methane (7%) or carbon dioxide (50%). Each year about 2.6 mol N/m super(2) of particulate nitrogen reaches the sediment; 1.1 mol/m super(2) is buried and 1.6 mol/m super(2) is mineralized to ammonium. Only 0.42 mol/m super(2)/yr of the ammonium produced escapes from the sediments, the remaining being first nitrified (1.2 mol/m super(2)/yr) and then denitrified (1.7 mol/m super(2)/yr). Simple calculations indicate that intertidal sediment may account for about 14% and 30% of the total estuarine retention of nitrogen and carbon, respectively.
AN: 3842997
148 of 1521
TI: Seasonal nitrogen dynamics in Chesapeake Bay: A network approach
AU: Baird,-D.; Ulanowicz,-R.E.; Boynton,-W.R.
AF: Chesapeake Biol. Lab., Univ. Maryland Syst., P.O. Box 38, Solomons, MD 20688, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1995 vol. 41, no. 2, pp. 137-162
LA: English
ER: M (Marine); B (Brackish)
AB: The input, exchange, recycling and export of nitrogen in the mesohaline region of Chesapeake Bay have been assessed in this study. The seasonal rate of exchanges between the 36 most important components and the roles of these in the recycling process of nitrogen in the ecosystem have been quantified. Results show that the demand for nitrogen by phytoplankton, bacteria and benthic algae is the highest in summer (418 mg N m super(-2) day super(-1)) and lowest in winter (90 mg N m super(-2) day super(-1)). The supply of dissolved nitrogen however, is highest in spring (289 mg N m super(-2) day super(-1)), with the lowest exogenous supply of 'new' nitrogen during summer (53 mg N m super(-2) day super(-1)). The seasonal variation in supply and demand suggest that spring nitrogen loadings continue to sustain the high nitrogen demand in summer when this nutrient appears to be in short supply. Results also show that the efflux of nitrogen from the sediments to the overlying water dominates the recycling process and is abetted by water column regeneration, mostly by the smaller biota (<200 mu m). Mesozooplankton, suspension-feeders and fish as a whole contribute relatively little on a seasonal or annual basis to the total amount of regenerated nitrogen. Network analysis of the seasonal dynamics of nitrogen indicates that the pathways over which nitrogen is recycled are considerably more complicated and numerous than those which retain carbon in the system. The Finn Cycling Index (FCI) reveals that the rate of nitrogen recycling during summer approximates 70% of the total system activity compared with the 34-46% range during other seasons. In contrast, the FCI for carbon was almost a constant 20% over all seasons. As regards the pelagic microbiota, which functionated more as a shunt to convey excess carbon out of the system, analysis indicates they comprise very significant pathways for the retention of nitrogen in the system.
AN: 3842411
149 of 1521
TI: Diel changes of nitrogen species in surface and overlying water of an estuarine lake in summer: Evidence for benthic-pelagic coupling
AU: Vanamuro,-M.; Koike,-I.
AF: Mar. Geol. Dep., Higashi 1-1-3, Isukuba, Ibakari, Japan
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 7, pp. 1726-1733
LA: English
ER: B (Brackish)
AB: Diel changes in the concentration of nitrogen species [ammonium, nitrite, nitrate, dissolved organic N, and particulate organic N (PON)] and some biological parameters were monitored in the water column of Lake Shinji, a shallow estuarine lake in Japan. The sediment of the lake was densely inhabited by the filter-feeding bivalve Corbicula japonica. An overlying water sampler showed that PON at the sediment-water interface (less than a few millimeters above the sediment) was not depleted; nevertheless, active uptake of PON by C. japonica (10.4 mg-atoms N/m super(2)/d) is reported. Dissolved and particulate N species showed vertically uniform profiles at night, which we attributed to nocturnal water mixing associated with cooling surface water. These observations suggest benthic-pelagic coupling between filter-feeding bivalves and phytoplankton which enables the removal of nitrogen from the eutrophic lake through fisheries yield of bivalves.
AN: 3842246
150 of 1521
TI: Empirical models of phosphorus and nitrogen excretion rates by zooplankton
AU: Wen,-Yuan-Hua; Peters,-R.H.
AF: Dep. Biol., McGill Univ., 1205 Ave. Dr. Penfiled, Montreal, PQ H3A 1B1, Canada
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 7, pp. 1669-1679
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Although rates of P and N excretion by zooplankton have important implications for nutrient cycling in aquatic ecosystems, the literature offers few quantitative general models of these processes. We used data collected from published studies to construct potentially predictive models of P and N excretion rates by zooplankton from freshwater and marine habitats. Excretion rates of P and N are strongly correlated (r super(2) = 0.88) and consequently each predicts the other best. Respiration rate is also highly significantly correlated with P and N excretion rates and is the second best predictor. Although body size explained relatively less overall variability, the inclusion of temperature, container volume, and experimental duration as independent variables in multiple regressions substantially improved the predictive power of models based on body size. The models can be corrected for taxonomic biases in zooplankton, but these biases were usually small. These models could provide both a basis for further empirical analysis of the determinants of zooplankton nutrient excretion and a means of predicting the fate of nutrients in aquatic ecosystems.
AN: 3842242
151 of 1521
TI: Oxygen regulation of nitrification and denitrification in sediments
AU: Rysgaard,-S.; Risgaard-Petersen,-N.; Sloth,-N.P.; Jensen,-K.; Nielsen,-L.P.
AF: Natl. Environ. Res. Inst., Vejlsovej 25, DK-8600 Silkeborg, Denmark
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 7, pp. 1643-1652
LA: English
ER: F (Freshwater)
AB: Oxygen regulation of nitrification and denitrification in sediments was investigated with super(15)N-isotope techniques. Sediment cores from Vilhelmsborg Lake, Denmark were incubated in a continuous flowthrough system in which the O sub(2) concentration was varied in the overlying water while the NO sub(3) super(-) concentration was kept constant. Nitrification was stimulated with increasing O sub(2) concentrations in the overlying water from 0 to 100% of atmospheric saturation, whereas only a slight stimulation was observed above 100%. At O sub(2) concentrations below 100% of atmospheric saturation, NO sub(3) super(-) from the overlying water was the most important source of N for denitrification, whereas above 100% of atmospheric saturation, NO sub(3) super(-) produced by nitrification was the main source of N for denitrification. The converse effects of the O sub(2) levels on the source of NO sub(3) super(-) can be explained by applying a simple one-dimensional model: O sub(2) in the overlying water controls the diffusional distance of NO sub(3) super(-) to the anoxic zone of denitrification and consequently the location of NO sub(3) super(-) vertically in the sediment as well as the magnitude of the nitrification activity. Our results suggest that in aquatic environments containing low NO sub(3) super(-) concentrations in the overlying water (such as coastal waters), higher O sub(2) conditions will stimulate denitrification, while the opposite will occur in systems containing high NO sub(3) super(-) concentrations (such as eutrophic lakes and streams).
AN: 3842230
152 of 1521
TI: Antarctic bottom water formation and the global cadmium to phosphorus relationship
AU: Frew,-R.D.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich, UK
SO: GEOPHYS.-RES.-LETT. 1995 vol. 22, no. 17, pp. 2349-2352
LA: English
ER: M (Marine)
AN: 3841078
153 of 1521
TI: Modelling of the end products of the chemical decomposition of DMS in the marine boundary layer
AU: Hertel,-O.; Christensen,-J.; Hov,-O.
AF: Natl. Environ. Res. Inst., Dep. Emissions and Air Pollution, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
SO: ATMOS.-ENVIRON. 1994 vol. 28, no. 15, pp. 2431-2449
LA: English
ER: M (Marine)
AB: A one-dimensional Lagrangian trajectory model (1DIM) with chemistry which includes a detailed description of the marine biogenic sulphur compounds is used to investigate the branching of the end products of the decomposition of DMS (methane sulphonic acid (MSA) and sulphate aerosols). Model runs for Brittany, France are compared with measurements form the OCEANO-NO sub(x) campaign in June 1989. The parameterization of the biogenic sulphur emissions is uncertain, but the modelled concentrations are in the right range and fit the observed concentrations fairly well. DMS is, however, often out of phase in time with the observed concentrations. This is probably due to a coastal effect linked to the shifting tide, which influences the DMS emissions. The observed ratio of MSA to SO sub(4) super(2-) is reproduced well. However, methane sulphinic acid (MSEA) concentrations comparable to and some times even higher than MSA are computed.
AN: 3838396
154 of 1521
TI: Growth characteristics of marine phytoplankton determined by cell cycle proteins: The cell cycle of Ethmodiscus rex (Bacillariophyceae) in the southwestern North Atlantic Ocean and Caribbean Sea
AU: Lin,-Senjie; Carpenter,-E.J.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: J.-PHYCOL. 1995 vol. 31, no. 5, pp. 778-785
LA: English
ER: M (Marine)
AB: Ethmodiscus spp. is an important contributor to oceanic tropical-ooze sediments and thus might be an important transport vehicle of carbon from the ocean surface to sediments. The knowledge of its cell cycle and growth rate, which is still lacking, is necessary to evaluate the importance of Ethmodiscus in nutrient cycling and to solve the discrepancy between its high sedimentary abundance and rarity in the plankton. We used immunofluorescence of a cell cycle protein, proliferating cell nuclear antigen (PCNA), and DNA-specific staining to study the progression of the cell cycle and roughly estimate the growth rate for E. rex (Rattray) Wiseman and Hendey in the southwestern North Atlantic Ocean and Caribbean Sea in June 1994 and January 1995. During the cell division cycle, the chloroplasts appeared to synthesize DNA before the nucleus (S phase). Following the S phase, the nucleus moved from one end of the cell toward the center underneath the midline of the girdle band (G2 phase) where it divided (M phase). During a very brief period, the parent cell split and moved apart from the girdle midline, and two new valves were produced (late M phase). The two daughter nuclei apparently remained attached at the joint of the two newly produced valves, where they appeared to be responsible for coordinating the symmetrical formation of the new valves. The morphologically complete daughter cells remained joined for a short period of time before separating into solitary cells whose nucleus was located at one end of the cell. Derived from the phase fraction curves, the duration of the cell cycle phases decreased in the order from G1, S, G2, to M. A conservative estimate of the growth rate in the study area obtained by using PCNA immunostaining was 0.39-0.46/d in June and 0.15/d in January. The validity and implication of the growth rate estimates are discussed.
AN: 3838286
155 of 1521
TI: Diagenetic evolution of the DOP facies from the Atlantis 2 Deep (Red Sea): Evidence of early hydrothermal activity
AU: Anschutz,-P.; Blanc,-G.
AF: Cent. Geochem. de la surface, UPR CNRS 6251, Inst. Geol., Univ. Louis Pasteur, 1 rue Blessig, 67084 Strasbourg Cedex, France
SO: OCEANOL.-ACTA 1995 vol. 18, no. 1, pp. 105-112
LA: French
ER: M (Marine)
AB: The 23,000 year old sediments of the Atlantis II Deep rest on a basaltic substratum and are overlaid by a dense and hot brine pool. The facies of the lower sequence of the West basin consists essentially of bioclastic and detrital particles (DOP facies). The primary calcite and aragonite of planktonic tests of the DOP facies have been transformed into Ca-, Mg-, Mn-, and Fe-carbonate solid solutions. Pyrite amounts to about 1-2% (wt) at the bottom of the sedimentary series, and as much as 20% (wt) in the upper part of the sequence. These high iron - and manganese - bearing minerals are the product of early diagenetic processes in an environment favourable to bacterial activity, to which biogenic and detrital particles, organic matter, and iron and manganese oxides were supplied. The high proportion of pyrite and secondary carbonates indicates that the environment of the W basin was different from the Red Sea pelagic environment during the deposition of the DOP facies, which take place between 23,000 and 11,000 years B.P. The super(87)Sr/ super(86)Sr ratios, approaching 0.708, and the conservation of siliceous tests indicate the occurrence of an initial brine pool in the Atlantis II Deep. The Deep was therefore hydrothermally active prior to 11,000 years B.P., i.e. before the deposition of the purely metalliferous facies that overlie the DOP facies.
AN: 3838116
156 of 1521
TI: Phosphatogenesis in Polynesian atolls: Cyanobacterial mats-phosphorite filiation.
OT: Phosphatogenese en atolls polynesiens: La filiation mattes cyanobacteriennes-phosphorites
AU: Jehl,-C.; Rougerie,-F.
AF: ORSTOM, Lab. Halieutique-Ecosystemes Aquatiques, 911 Ave. Agropolis, BP 5045, 34032 Montpellier Cedex 1, France
SO: OCEANOL.-ACTA 1995 vol. 18, no. 1, pp. 79-93
LA: French
ER: M (Marine)
AB: Brackish ponds and lagoons located on Polynesian atolls are frequently colonized by thick cyanobacterial mats. The accumulated organic material (OM) is preserved due to prevailing anoxia. The high productivity of these microbial mats is controlled by high nutrient contents in the interstitial waters of the underlying limestone, in accordance with the geothermal endo-upwelling process (Rougerie and Wauthy, 1986, 1993). Observations and micro-analysis carried out on insular phosphate samples, and a comparative study of hydrocarbons extracted from kopara and phosphate, indicate a genetic link between the diagenetic evolution of the trapped OM and the apatite precipitation as follows: growth of thick microbial mats in brackish ponds and closed lagoons, and anoxic preservation of OM; oxydative degradation of these OM, liberation of PO sub(4) super(3-) ions to apatite saturation; primary apatite precipitation and phosphatization of the detrital carbonates through substitution of CO sub(3) by PO sub(4); polyphasic enrichment of the phosphate deposit induced by eustatic changes, through primary apatite dissolution and secondary apatite precipitation. This model of phosphogenesis provides explanations that are both qualitative (trapped organic matter and apatite substitution by elements in ratios corresponding to those of deep marine waters) and quantitative (10 super(6) to 10 super(8) tons of apatite accumulated on small atolls), lacking in previous models (degradation of guano or volcanic material).
AN: 3838114
157 of 1521
TI: Taxonomic diversity and metabolic activity of microbial communities in the water column of the Central Baltic Sea
AU: Hoefle,-M.G.; Brettar,-I.
AF: Gesellsch. Biotechnol. Forsch. mbH, Bereich Mikrobiol., Mascheroder Weg 1, D-38124 Braunschweig, FRG
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 5, pp. 868-874
LA: English
ER: M (Marine); B (Brackish)
AB: The water column of the Gotland Deep, an anoxic basin in the central Baltic Sea, was investigated as a representative and well-characterized part of a coastal marine ecosystem. We analyzed the overall structure of the bacterioplankton community by high resolution electrophoresis of the low-molecular-weight RNA (LMW RNA = 5S rRNA and tRNA). The results gave us a direct overview of the taxonomic diversity of the bacterial community (i.e. the number of taxa and their relative amounts in a sample). For further information about the identity of single taxa, we used partial sequencing of the 5S rRNA. Throughout the water column, we observed a rather limited number of abundant bacterial taxa (i.e. 3-7) with an increase of bacterial diversity in layers of increased turnover of organic matter. Comparison of samples taken from the euphotic zone during two consecutive summers indicated high similarity of taxonomic structure. One of the 5S rRNA bands occurring at the oxic-anoxic interface showed a partial sequence identical to Thiobacillus denitrificans, a species whose presence was hypothesized earlier from biogeochemical investigations. By using this novel approach, we could combine a direct overview of bacterial diversity with the ability to further analyze single species and thus provide means to elucidate major bacterial catalysts of biogeochemical cycling.
AN: 3838068
158 of 1521
TI: Copepod grazing and the biogeochemical fate of diatom iron
AU: Hutchins,-D.A.; Wang,-Wen-Xiong; Fisher,-N.S.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 5, pp. 989-994
LA: English
ER: M (Marine)
AB: We investigated the effects of copepod grazing on fractionation of diatom cellular Fe into assimilated, dissolved, and fecal pellet pools. Grazer assimilation was only weakly dependent on prey N : Fe ratios, with assimilation efficiencies approximately tripling over a 100-fold increase in diatom N : Fe ratios. Assimilation efficiencies strongly correlated with prey subcellular partitioning, however, exhibiting a 1 : 1 relationship to cell cytoplasmic content and a 1 : 3 relationship with diatom intracellular content. Release of Fe from copepod fecal pellets conformed with a two-compartment loss model, with roughly 80% of associated Fe in a slowly released pool (tb sub( one half ) = 113 d). Partitioning into dissolved, assimilated, and fecal pellet pools indicated that all three are important fates for ingested cellular Fe.
AN: 3838061
159 of 1521
TI: In situ measurements of seawater pCO sub(2)
AU: DeGrandpre,-M.D.; Hammar,-T.R.; Smith,-S.P.; Sayles,-F.L.
AF: Dep. Mar. Chem. and Geochem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 5, pp. 969-975
LA: English
ER: M (Marine)
AB: A new instrument for studying seawater pCO sub(2) dynamics is described. The Submersible Autonomous Moored Instrument for CO sub(2) (SAMI-CO sub(2)) operates by equilibration of ambient seawater pCO sub(2) with a colorimetric pH indicator contained in a gas-permeable membrane. The indicator is periodically renewed to improve the stability and sensitivity typically reported for similar indicator-based pCO sub(2) sensors. The design combines off-the-shelf optical components, a miniature solenoid pump and valve, a low power data logger, and a fiber-optic flow cell to achieve low power consumption and easy assembly. SAMI-CO sub(2) is designed to operate down to 100 m and contains sufficient batteries and reagent for deployment up to 6 months while making 48 measurements per day. Extensive in situ field tests have been performed, including deployment in Woods Hole Harbor for > 30 d (May-June 1994). The field evaluation has confirmed that SAMI-CO sub(2) is capable of measuring seawater pCO sub(2) with exceptional long-term stability (no detectable drift in 1 month) and sensitivity comparable to ship-based equilibrator-infrared methods ( plus or minus 1 mu atm). The time-series data obtained from this study show that pCO sub(2) can be highly variable in nearshore environments with up to 100- mu atm changes detected over a 4-h period. The structurally rich data highlight the need for continuous mooring-based measurements of pCO sub(2) for understanding carbon cycling in natural waters.
AN: 3838058
160 of 1521
TI: Interspecific variability and environmental influence on particulate organic carbon delta super(13)C in cultured marine phytoplankton
AU: Leboulanger,-C.; Descolas-Gros,-C.*; Fontugne,-M.R.; Bentaleb,-I.; Jupin,-H.
AF: Lab. Hydrobiol., URA CNRS 1355, Univ. Montpellier II, F-34095 Montpellier Cedex 5, France
SO: J.-PLANKTON-RES. 1995 vol. 17, no. 11, pp. 2079-2091
LA: English
ER: M (Marine)
AB: The stable carbon isotope composition of particulate organic matter expressed as delta super(13)C was measured in cultures of 13 species of marine microalgae in different phylogenetic groups. The effects of salinity variations and changes in photoperiod were also assayed for three of them (i.e. Skeletonema costatum, Amphidinium operculatum and Isochrysis galbana); the effect of nature of nitrogen supply (nitrate, ammonium) was studied for one (S. costatum). These environmental parameters were chosen because of their variability in the ocean and their possible effects of delta super(13)C values of phytoplankton organic carbon. Batch culture conditions and sampling time after inoculum were strongly controlled in order to provide cells in good physiological state which were comparable from one culture to the other. In the same way, sampling was limited to the first 2 days of exponential growth, in order to avoid a possible dissolved inorganic carbon (DIC) limitation. Carboxylase activities [of the enzyme ribulose 1,5-bisphosphate carboxylase oxygenase (Rubisco), and the three beta carboxylases: phosphoenolpyruvate carboxylase (PEPC), phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate carboxylase (PC)] and total chlorophyll a concentrations were assayed simultaneously. The delta super(13)C values observed were between -30.2ppt and -12.7ppt i.e. comparable to those observed in the world's oceans. The isotopic composition of phytoplankton organic carbon was shown to be under the influence of the paramaters tested but delta super(13)C variations are specific to the species considered. The nature of beta carboxylase found in each species, or systematic position, could not be linked to the isotopic composition of organic carbon. No linear or single correlation between delta super(13)C variations and environmental modifications were observed and there is no evidence for a simple and universal relation between delta super(13)C of phytoplankters and their environment. In monospecific cultures as in the field, delta super(13)C fractionation by Rubisco (and eventually by PEPCK) may be counterbalanced by other mechanisms.
AN: 3837979
161 of 1521
TI: Evidence for the seasonal accumulation of carbon-rich dissolved organic material, its scale in comparison with changes in particulate material and the consequential effect on net C/N assimilation ratios
AU: Williams,-P.J.leB.
AF: Sch. Ocean Sci., Univ. Wales, Bangor, Menai Bridge, Gwynedd, UK
SO: MAR.-CHEM. 1995 vol. 51, no. 1, pp. 17-29
LA: English
ER: M (Marine)
AB: An analysis is made of the seasonal cycles of particulate and dissolved organic carbon and nitrogen. The seasonal increase of the dissolved organic fraction (DOM) at all the sites studied is comparable to or exceeds that of the particulate fraction. The analysis revealed a mid-to late-summer accumulation of C-rich DOM, with C/N ratios twice or more the Redfield value of 6.6. It is illustrated that the formation of this C-rich material would give rise to net inorganic carbon and nitrogen assimilation ratios as high as 14:1, as such the could be the basis of high reported C/N assimilation ratios. Nitrogen limitation is speculated as a cause for the accumulation of the C-rich material. It is argued that systematic errors in the analytical methods would not give the patterns observed. The significance of accumulation of C-rich DOM in late summer is discussed in relation to reports which infer DOC to be a major form of carbon export from the euphotic zone. It is argued that the weak biochemical coupling of C and N in DOM as compared with the particulate fraction would loosen the link between the export of organic carbon and the import of inorganic nitrogen with important consequences on the biogeochemical control of carbon export from the upper ocean.
AN: 3835127
162 of 1521
TI: Accumulation of organic carbon in bottom sediments of the Benguela Upwelling zone.
OT: Nakoplenie organicheskogo ugleroda v donnykh osadkakh zony Bengel'skogo apvellinga
AU: Vetrov,-A.A.; Romankevich,-E.A.; Sipajlo,-L.E.
AF: Inst. Okeanol., Moscow, Russia
SO: OKEANOLOGIYA 1995 vol. 35, no. 4, pp. 550-555
LA: Russian
ER: M (Marine)
AB: The patterns of distribution and accumulation of organic matter in the recent epoch and the last glacial period are analized on the basis of sediment and pore water samples collected at sections along 17 degree S (62-4085 m depth), 23 degree S (42-3220 m) and 25 degree S (60-1010 m). The analysis revealed the following characteristics: not only high percentage concentrations of C sub(org) but accumulation of its considerable absolute masses caused by increased bioproductivity due to upwelling; decline of percentage C sub(org) concentrations in the shelf-slope-foot system and an even sharper decrease in its absolute masses; confinement of high absolute masses of C sub(org) and sediments to shallow water sediments of the inner shelf opposite Cunene R.; burial in the Cunene R. discharge zone during the glacial period of much higher absolute masses of sediments and C sub(org), which is characteristic of processes in the zones with a distinct type of avalanche sedimentation.
AN: 3834981
163 of 1521
TI: Aliphatic amines in Chesapeake Bay sediments
AU: Burdige,-D.J.; Huang,-C.M.; Krishna,-N.; Scully,-F.E.,Jr.
AF: Dep. Oceanogr., Old Dominion Univ., Norfolk, VA 23529, USA
SO: MAR.-CHEM. 1995 vol. 51, no. 1, pp. 45-54
LA: English
ER: M (Marine)
AB: Aliphatic amines were determined in sediments and sediment pore waters from several contrasting sites in Chesapeake Bay. The aliphatic amines diethylamine, sec-butylamine, n-propylamine, and i-propylamine were detected in a limited number of pore-water samples at concentrations generally less than similar to 0.6 mu M. The occurrence of these amines showed no obvious correlation to other sediment geochemical parameters. Whole sediment (HF/HCl-extractable) aliphatic amines were less than similar to 0.8 nmol/gdw. Isoamylamine and 2-methylbutylamine were the only amines that could be detected and quantified in sediment extracts, although diethylamine was below our detection limit in selected samples. When compared to other measured nitrogen pools in the sediments, these observations suggested that aliphatic amines may not represent a significant fraction of the nitrogen that is remineralized in these sediments, although more detailed concentration and rate studies are needed to verify their role in sediment nitrogen cycling. These aliphatic amines also did not appear to represent a major component of the uncharacterized nitrogen in these sediments.
AN: 3834816
164 of 1521
TI: The microbial food web in the European Regional Seas Ecosystem Model
AU: Baretta-Bekker,-J.G.; Baretta,-J.W.; Koch-Rasmussen,-E.
AF: Ecol. Modelling Cent., Joint Dep. DHI/VKI, Agern Alle 5, DK-2970 Horsholm, Denmark
SO: NETH.-J.-SEA-RES. 1995 vol. 33, no. 3-4, pp. 363-379
LA: English
ER: M (Marine)
AB: In the framework of the complex dynamical European Regional Seas Ecosystem Model (ERSEM) a module describing the microbial part of the pelagic ecosystem has been developed. The module contains the carbon and nutrient dynamics of pelagic bacteria, heterotrophic flagellates and microzooplankton and interacts with the other parts of the model via phytoplankton, particulate and dissolved organic matter and mesozooplankton. A short description of the module is given and the results are discussed. It is demonstrated that in an application of ERSEM to the North Sea there is a gradual shift in dominance from the continental coast boxes to the offshore deeper areas between the different food webs, from what in the literature is termed the classical food web to the microbial food web, concomitant with a gradual decrease in the efficiency of the microbial loop.
AN: 3834745
165 of 1521
TI: Modelling primary production in the North Sea using the European Regional Seas Ecosystem Model
AU: Varela,-R.A.; Cruzado,-A.; Gabaldon,-J.E.
AF: Cent. Estud. Av. Blanes, Cami Santa Barbara s/n, E-17300 Blanes (Girona), Spain
SO: NETH.-J.-SEA-RES. 1995 vol. 33, no. 3-4, pp. 337-361
LA: English
ER: M (Marine)
AB: The primary production module incorporated in the European Regional Seas Ecosystem Model (ERSEM) is described in detail. It considers two phytoplankton groups, diatoms and autotrophic flagellates, and four different nutrients: nitrate, ammonia, phosphate and silicate (only for diatoms). All the related state variables and fluxes are represented in terms of carbon, nitrogen, phosphorus and silicon. The potential carbon growth rate process is estimated by considering that nutrient availability acts as a limitation factor on the maximum growth rate which is itself a function of light and water temperature. Respiration, excretion of organic matter, lysis and sinking are the main carbon and nutrient loss processes. Results indicate that the model simulates well the annual phytoplankton dynamics in the central regions of the North Sea, underestimating primary production and chlorophyll in the southern North Sea. The model gave good correlations with the main dissolved nutrients, such as silicate, phosphate or nitrate. The primary production module proved to be especially sensitive to the flagellate/diatom interaction and competitive behaviour for inorganic nutrients as well as with regard to grazing losses. It is suggested that a major improvement could be made by including a third phytoplankton group (e.g., Phaeocytis) in the model structure, and that comparison with other phytoplankton growth schemes based on the Droop formulation is advisable.
AN: 3834744
166 of 1521
TI: Nutrient dynamics in the North Sea: Fluxes and budgets in the water column derived from ERSEM
AU: Radach,-G.; Lenhart,-H.J.
AF: Inst. Meeresk., Univ. Hamburg, Troplowitzst. 7, D-22529 Hamburg, FRG
SO: NETH.-J.-SEA-RES. 1995 vol. 33, no. 3-4, pp. 301-335
LA: English
ER: M (Marine)
AB: Nutrient dynamics for phosphate, nitrate, ammonium and silicate have been simulated with ERSEM, the European Regional Seas Ecosystem Model. From the model results budgets for the dissolved inorganic nutrients and the corresponding particulate fractions have been calculated. The annual cycles of the nutrients phosphate and silicate compare quite well with the observed ranges of variability. This does not hold for ammonium and nitrate. Biologically mediated transformations such as nutrient uptake and pelagic and benthic mineralization are the dominant processes in changing the nutrient concentrations with the horizontal advective contributions playing a minor role during the productive season. Vertical advection and vertical diffusion have a clear seasonal signal, with a maximum in February. The decay of the advective nutrient transport in summer is caused by the depletion of the upper layer of dissolved inorganic nutrients by algal uptake. The inflow of nutrients in the northwest is almost balanced by the outflow in the northeast, without causing large nutrient transports into the shallower areas from the north. However, from the coastal areas there is a nutrient flow towards the central North Sea, enhancing primary production in the central area.
AN: 3834743
167 of 1521
TI: Geochemical and isotopic comparisons between northern Lake Michigan and Conception Bay, Newfoundland
AU: Ostrom,-N.; Lee,-D.; Hall,-D.; Ostrom,-P.
AF: Dep. Geol. Sci., Michigan State Univ., East Lansing, MI 48824, USA
CO: 37. Conference of the International Association of Great Lakes Research and Estuarine Research Federation, Windsor, ON (Canada), 5-9 Jun 1994
SO: 37TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH-AND-ESTUARINE-RESEARCH-FEDERATION:-PROGRAM-AND-ABSTRACTS. International-Assoc.-for-Great-Lakes-Research,-Buffalo,-NY-USA BUFFALO,-NY-USA IAGLR 1994 166
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Northern Lake Michigan and Conception Bay, Newfoundland and although having contrasting salinities are similar in size, depth, climate, and alkalinity. Water column geochemical and isotopic data collected in these two systems are compared. Samples were collected off Frankfort, MI in July of 1992 and are compared to samples collected in July of 1990 in Conception Bay. Concentrations of oxygen, as determined by a Seabird CTD, in Lake Michigan, ranged between 2.4 and 8.5mL/L. A narrow (<10 m) wide oxygen minimum zone was evident at the base of the thermocline. Concentrations within the minimum zone decreased from 5.6 mL/L to 2.4 mL/L over a 24 hour period. Bottle collections were used in Conception Bay and may be the reason why an oxygen minimum zone was not observed. In both systems, the concentration of particulate organic matter (POM) decreased markedly across the thermocline. Marked increases in the delta super(15)N of POM were also evident in both systems. In Lake Michigan the delta super(15)N of POM increased with depth from values as low as 4.0 to a maximum of 17.7ppt. A minimum in carbon isotope values was also associated with the thermocline in both systems. These trends clearly indicate that the base of the thermocline is a region of intense microbial cycling. The delta super(15)N of nitrate in Lake Michigan varied between-1.3 and 1.5ppt and was similar to the average delta super(15)N of nitrate in Conception Bay of 0.2ppt. These values indicate that nitrate was derived similarly in both systems; from nitrification in sediments in which substantial isotopic fractionation was involved.
AN: 3832039
168 of 1521
TI: Benthic organic nitrogen mineralization dynamics: Comparison of results from sites in Lake Michigan and the Gulf of Mexico
AU: Gardner,-W.S.
AF: NOAA Great Lakes Environ. Res. Lab., 2205 Commonwealth Blvd., Ann Arbor, MI 48105, USA
CO: 37. Conference of the International Association of Great Lakes Research and Estuarine Research Federation, Windsor, ON (Canada), 5-9 Jun 1994
SO: 37TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH-AND-ESTUARINE-RESEARCH-FEDERATION:-PROGRAM-AND-ABSTRACTS. International-Assoc.-for-Great-Lakes-Research,-Buffalo,-NY-USA BUFFALO,-NY-USA IAGLR 1994 166
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Comparison of results from studies of benthic nitrogen mineralization and fate in Lake Michigan and in the Gulf of Mexico (near the Mississippi River plume) suggest interesting similarities and differences in benthic nitrogen dynamics between freshwater and marine coastal ecosystems. Excretion of ammonium by benthic macroinvertebrates was an important component (ca 10 to 40%) of total benthic organic nitrogen mineralization in both Lake Michigan and the Gulf of Mexico, an observation that supports the hypothesis of relatively direct transfer of nitrogen-rich particles from the euphotic zone to the benthos. However, the fate of the regenerated nitrogen was somewhat different in the two ecosystems. In the Gulf of Mexico experiments, a relatively large portion (24-65%) of the regenerated nitrogen was released into the water column as ammonium whereas in Lake Michigan, virtually all of the regenerated nitrogen was denitrified to nitrogen gas. This result is consistent with the hypothesis that sea salts enhance ammonium mobility across the sediment-water interface by forming ion pairs with ammonium and blocking cation exchange sites in the sediments.
AN: 3832035
169 of 1521
TI: The linkage of organic contaminant and natural organic matter cycling in the Great Lakes
AU: Eisenreich,-S.J.; Baker,-J.E.
AF: Gray Freshwat. Biol. Inst., P.O. Box 100, Navarre, MN 55392, USA
CO: 37. Conference of the International Association of Great Lakes Research and Estuarine Research Federation, Windsor, ON (Canada), 5-9 Jun 1994
SO: 37TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH-AND-ESTUARINE-RESEARCH-FEDERATION:-PROGRAM-AND-ABSTRACTS. International-Assoc.-for-Great-Lakes-Research,-Buffalo,-NY-USA BUFFALO,-NY-USA IAGLR 1994 166
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Our hypothesis is that the concentration, residence time, and fate of hydrophobic organic chemicals (HOCs) such as PCBs and many organochlorine pesticides in large aquatic systems such as the Great Lakes and Chesapeake Bay are controlled by the production, settling, mineralization, recycling, and burial of natural organic matter. HOCs partition into particulate organic matter (algae) in the surface waters and are delivered to the benthic region at rates of perhaps 5 to 100 m/day, thereby reaching the benthic region even in the deepest waters of Lake Superior in days to a few weeks. Several data sets from Lakes Superior and Michigan, Green Bay, and Chesapeake Bay exhibit specific linear relationships between PCB flux and OC flux. The PCB flux per unit of OC flux decreases from oligotrophic to eutrophic systems indicative of biomass dilution and changes in the quality of the available lipid pool. As the autochthonous matter is mineralized and re-packaged by benthic organisms, HOCs are released and are re-distributed into the available particle pool. In much of the Great Lakes, surface sediment is resuspended on a seasonal basis except for deep waters re-supplying the surface water with HOCs. The efficiency of recycling of PCBs in the benthic region is dependent on the hydrophobicity of the chemical; benthic recycling rates of PCBs in Lake Superior range from similar to 10 for highly chlorinated congeners to similar to 500-1,000 for dichloro-congeners. The factor most important in determining the sediment concentration of HOCs is likely the degree of organic matter preservation in the surface sediments. Specific examples from Lakes Superior and Michigan, Green Bay, and Chesapeake Bay will be presented.
AN: 3832034
170 of 1521
TI: The comparative geochemistry of trace metals in estuaries and lakes
AU: Church,-T.M.
AF: Coll. Mar. Stud., Univ. Delaware, Newark, DE 19716-3501, USA
CO: 37. Conference of the International Association of Great Lakes Research and Estuarine Research Federation, Windsor, ON (Canada), 5-9 Jun 1994
SO: 37TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH-AND-ESTUARINE-RESEARCH-FEDERATION:-PROGRAM-AND-ABSTRACTS. International-Assoc.-for-Great-Lakes-Research,-Buffalo,-NY-USA BUFFALO,-NY-USA IAGLR 1994 166
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Trace elements are introduced to lakes and coastal waters by both eolian and riverine/estuarine means from the weathering of rocks and waste disposal. The anthropogenic fraction introduced currently outweighs the natural fraction for most non-crustal elements for many estuaries and lakes in at least North America. Trace metals which enter seepage or Great Lakes is dominated by direct atmospheric deposition. Direct and indirect atmospheric deposition dominates trace metal input probably to estuarine and certainly to coastal waters of the mid-Atlantic region. In freshwater lakes the metals are processed largely by the natural Eh-pH biogeochemical cycles which eventually lead to their sediment deposition. In estuaries, trace elements are processed by both the chemical (Eh-pH) as well as salt (ionic strength) gradient inherent in their transmission from the land to the sea. Elements which readily hydrolyze (e.g., Fe, Mn, and Co) are geochemically processed and retained as sediments, while those that participate in biochemical cycles (e.g., Cu, Ni, and Zn) are reprocessed into robust organic complexes that are largely transmitted into the sea.
AN: 3832033
171 of 1521
TI: A simple model of biogeochemical element distribution in the oceanic water column
AU: Shopova,-D.; Dehairs,-F.; Baeyens,-W.
AF: Environ. Res. and Info. Cent., Sofia, Bulgaria
SO: J.-MAR.-SCI. 1995 vol. 6, no. 4, pp. 331-344
LA: English
ER: M (Marine)
AB: In the present paper a simple technique for data analysis of the distribution of biogeochemical elements in the oceanic water column is presented. It is based on a steady vertical model, which assumes that the turbulent diffusion and vertical advection are the main physical mechanisms influencing the conservative tracer concentration. The production/consumption rates of non-conservative tracers are computed on the basis of this model. Sensitivity analysis of this model has been performed, which permits assessing the eventual influence of horizontal advection on the results. It also permits the taking into account of its effects if some hypothesis for the horizontal gradients are made. The potential area of applicability of the presented simple technology for data analysis is broad. Examples of its application are presented as analysis of the oxygen data for some stations of the INDIGO3, 1987 expedition in the Southern Ocean. The calculated oxygen consumption rates for the Antarctic Circumpolar Current (Indian Ocean Sector) range between 1.8 and 2.22 mmol m super(-) super(2)/d plus or minus 20%.
AN: 3831650
172 of 1521
TI: Benthic nutrient regeneration in the ERSEM ecosystem model of the North Sea
AU: Ruardij,-P.; Van-Raaphorst,-W.
AF: Netherlands Inst. Sea Res., P.O. Box 59, NL-1790 AB Den Burg, Texel, Netherlands
SO: NETH.-J.-SEA-RES. 1995 vol. 33, no. 3-4, pp. 453-483
LA: English
ER: M (Marine)
AB: In any ecosystem modelling approach to shallow seas an adequate description of the sediment-water interactions to all the essential nutrients is necessary. With this aim a fairly simple concept has been developed and applied for the modelling of the nutrient cycles of N, P and Si which includes the essential diagenetic processes such as vertical transport, oxic and anoxic mineralization, silicate dissolution, adsorption, nitrification and denitrification. All these processes are explicitly formulated for one or more distinct layers in the sediment. The model contains a low number of variables and is efficient with respect to computer time. The model is part of the European Regional Seas Ecosystem Model (ERSEM) of the North Sea, a joint effort of several institutes around the North Sea. The benthic-pelagic coupling of the ERSEM model is discussed with emphasis on the consequences for the benthic nutrient cycling and the interrelations between the different benthic nutrient submodels. The results show that the model is able to describe the seasonal variation of nutrient fluxes including the sediment-water exchanges and the vertical profiles in the pore water. From the model results is concluded that changes in organic matter deposition directly influence the benthic nitrification and denitrification through changes in the oxygen availability to the nitrifiers and, due to this, the supply of nitrate to the denitrifiers. Short fluctuations in organic deposition (e.g. after the spring bloom) are not reflected in the fluxes due to sorption buffering of phosphate in the oxidized surface layer of the sediment.
AN: 3831574
173 of 1521
TI: The benthic biological submodel in the European Regional Seas Ecosystem Model
AU: Ebenhoeh,-W.; Kohlmeier,-C.; Radford,-P.J.
AF: Carl von Ossietzky Univ., Postfach 2503, D-2611 Oldenburg, FRG
SO: NETH.-J.-SEA-RES. 1995 vol. 33, no. 3-4, pp. 423-452
LA: English
ER: M (Marine)
AB: The submodel describing benthic biology including a bioturbation module as incorporated in the European Regional Seas Ecosystem Model (ERSEM) is discussed. It is linked to a nutrient dynamic model. The structure of the benthic model food web is presented. There are four macrobenthic functional groups, meiobenthos and aerobic and anaerobic bacteria. The modelling uses 'standard organisms' as basic building blocks. The choice of parameter values is discussed. The results demonstrate the dependence of the benthic system on the pelagic system. The importance of features such as predation within functional groups for stability of the system is investigated. Detritus input from the pelagic system and detritus recycling is most important in the benthic food web. The web of carbon and nutrient fluxes through the system is analysed. On the basis of the food web analysis, the trophic positions of the functional groups are calculated. Besides the benthic biology, the mathematical formulation of the bioturbation and diffusion enhancement is discussed. Macrobenthic presence and activity enhance diffusion in the sediment and contribute essentially to vertical transport of particulate matter. This is of great importance for the vertical distribution of detritus, and as a consequence, for microbial activity in the sediment layers.
AN: 3831573
174 of 1521
TI: Modelling the predation, growth and population dynamics of fish within a spatially-resolved shelf-sea ecosystem model
AU: Bryant,-A.D.; Heath,-M.R.; Broekhuizen,-N.; Ollason,-J.G.; Gurney,-W.S.C.; Greenstreet,-S.P.R.
AF: Culterty Field Stn, Univ Aberdeen, Newburgh, Grampian AB41 OAA, UK
SO: NETH.-J.-SEA-RES. 1995 vol. 33, no. 3-4, pp. 407-421
LA: English
ER: M (Marine)
AB: The development and analysis of a fish population module within the European Regional Seas Ecosystem Model (ERSEM) is described. Fixed predation rates on ERSEM zooplankton and zoobenthos, which may be used in place of this dynamic module of fish, are described also. The dynamic module is age-structured, with state variables for the number of individuals and their weight, the latter partitioned into structural (skeletal, essentially) and remobilizable 'reserve' components. It is capable of prediction of observed patterns of both positive and negative changes in individual weight. The fish are modelled as one population for the whole North Sea, superimposed on the ERSEM box structure. Parameters have been derived from the literature where possible and, for herring (Clupea harengus), certain parameters have been adjusted to match independent estimates of growth in the field. Preliminary results show that herring growth rate depends inversely on biomass, when changes in the latter are caused by altered fishing mortality. The magnitude of these effects is in agreement with historical data for herring in the North Sea. The model is discussed in relation to previous attempts to model fish population dynamics, particularly in the North Sea.
AN: 3831572
175 of 1521
TI: Modelling the dynamics of the North Sea's mesozooplankton
AU: Broekhuizen,-N.; Heath,-M.R.; Hay,-S.J.; Gurney,-W.S.C.
AF: Natl. Inst. Water Atmos. Res., P.O. Box 11-115, 100 Aurora Terrace, Hillcrest, Hamilton, New Zealand
SO: NETH.-J.-SEA-RES. 1995 vol. 33, no. 3-4, pp. 381-406
LA: English
ER: M (Marine)
AB: A simple biomass-only zooplankton submodel is presented, describing the dynamics of copepods and carnivorous zooplankton in the North Sea. This submodel together with the other process-oriented submodels (viz. phytoplankton dynamics, the microbial food web, benthic processes, fish dynamics and large-scale advective transport) forms a spatially resolved simulation model of the North Sea ecosystem, the European Regional Seas Ecosystem Model (ERSEM). A large set of field measurements of zooplankton abundance has been assembled against which to compare the ERSEM's performance. These data are not only internally consistent, but have also been gathered at the large spatial scales appropriate to the ERSEM. In addition to the spatially resolved, monthly estimates of zooplankton abundance, several instantaneous, in situ estimates of the carbon fluxes between different components of the planktonic web in the northern North Sea are presented. Simulated dynamics are in good agreement with the data only during the mid-summer to mid-winter period. During the latter part of the winter and throughout the spring period zooplankton abundance is under-predicted and the simulated zooplankton growth rate is overpredicted during spring. The excessive decline of mesozooplankton biomass during winter may be caused by failing to capture many of the behavioural/physiological changes which zooplankton manifest during winter. It is suggested that the excessive spring growth is a consequence of a. a failure to properly distinguish between somatic and population growth, b. an inadequate representation of the small scale processes which influence feeding success, and c. an excessive spring phytoplankton bloom. The large phytoplankton bloom is, in part at least, a consequence of the excessively low simulated standing crop of omnivorous zooplankton in spring.
AN: 3831571
176 of 1521
TI: Molecular approaches to the study of aquatic and sedimentary organisms
AU: Nealson,-K.H.
AF: Cent. Great Lakes Stud., Univ. Wisconsin, 600 E. Greenfield Ave. Milwaukee, WI 53204, USA
CO: 37. Conference of the International Association of Great Lakes Research and Estuarine Research Federation, Windsor, ON (Canada), 5-9 Jun 1994
SO: 37TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH-AND-ESTUARINE-RESEARCH-FEDERATION:-PROGRAM-AND-ABSTRACTS. International-Assoc.-for-Great-Lakes-Research,-Buffalo,-NY-USA BUFFALO,-NY-USA IAGLR 1994 166
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Molecular genetics have supplied us with a variety of new approaches for the study of biogeochemistry and nutrient cycling. First, we have used molecular methods of hybridization, cloning, gene sequencing, and replacement mutagenesis to gain insight into factors that regulate metal reduction in the facultative anaerobe Shewanella putrefaciens. Such information allows one to predict the in situ activity of these bacteria in various environments. These approaches have revealed the presence of a regulatory gene that controls anaerobic respiration of several electron acceptors. Molecular methods are also in use to study the distribution and abundance of S. putrefaciens. Using hybridization probes directed at the 1 6S rRNA, it is now possible to directly identify the number of this species present in water samples. We are now cloning the gene for iron reduction [Fe(III) reductase], and when it is sequenced, it should allow us to develop function specific probes for the identification of iron reducers. Such approaches have been used successfully to identify species of luminous bacteria, using luxA gene probes. Finally, in collaboration with Dr. David Stahl, we are investigating the total sediment populations of Lake Michigan sediments by nucleic acid extraction and analysis. Preliminary results of these studies suggest that the organisms that are cultured using standard methods are markedly different from those seen in the nucleic acid profiles.
AN: 3831507
177 of 1521
TI: The benthic boundary layer of large lakes: Particle dynamics and biogeochemical cycling from the bottom looking up
AU: Klump,-J.V.
AF: Cent. Great Lakes Stud., Univ. Wisconsin-Milwaukee, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA
CO: 37. Conference of the International Association of Great Lakes Research and Estuarine Research Federation, Windsor, ON (Canada), 5-9 Jun 1994
SO: 37TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH-AND-ESTUARINE-RESEARCH-FEDERATION:-PROGRAM-AND-ABSTRACTS. International-Assoc.-for-Great-Lakes-Research,-Buffalo,-NY-USA BUFFALO,-NY-USA IAGLR 1994 166
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: The importance of processes within the benthic boundary layer of large lakes is well recognized, but not yet fully understood. With water residence times that vary from a few years to a few centuries, nearly all lakes can be characterized as under the strong influence of benthic boundary layer dynamics. Nearly all cycles, whether of elements of biogeochemical interest or of exotic contaminants, are driven, in part, by the dynamics of the processes coupling pelagic and benthic systems. Long-term deposition patterns and the spatial distribution of sediment accumulation are now known for a number of the Great Lakes, and estimates of the permanent burial of sedimentary components in simple mass balances for these systems are possible. Our understanding of the short-term dynamics of particle movement, vertical resuspension, and horizontal redistribution is much less certain, and although much is made, for example, about the role of the so-called nepheloid layer in a variety of cycles, the dynamics of that system are poorly characterized. Major questions still exist with regard to the mechanisms controlling sediment-water chemical exchange; the scale, spin-up, and decay of boundary layer phenomena; and the place of benthic energy transfer in the ecology of lakes. An attempt will be made to look into the possible role of future technology in addressing some of these gaps in our knowledge.
AN: 3831505
178 of 1521
TI: Preferential flow and segregation of porewater solutes in wetland sediment
AU: Harvey,-J.W.; Chambers,-R.M.; Hoelscher,-J.R.
AF: United States Geol. Surv., Water Resour. Div., Mail Stop 496, 345 Middlefield Rd., Menlo Park, CA 94025, USA
CO: Pulsed Ecosystems: A New Paradigm?, Hilton Head, SC (USA), Nov 1993
SO: PULSED-ECOSYSTEMS:-A-NEW-PARADIGM?-PROCEEDINGS-OF-A-SYMPOSIUM-HELD-IN-HILTON-HEAD,-NOVEMBER-1993. Blum,-L.K.-ed. 1995 vol. 18, no. 4 pp. 568-578
ST: ESTUARIES vol. 18, no. 4
LA: English
ER: B (Brackish)
AB: Sediment macropores (with effective diameters larger than 100 mu m) comprise 11% of the bulk sediment volume in a tidal freshwater wetland vegetated with Peltandra virginica. In order to determine effects of macroporous sediment structure on solute transport, we conducted a solute tracer experiment in the sediment. The effective transport volume ( theta sub(eff), the volume of sediment through which solute was transported normalized to sediment bulk volume) was 0.15 cm super(3) cm super(-3), which is considerably smaller than the total pore space that is potentially available for transport (porosity of sediment is 0.63 cm super(3) cm super(-3)). A mean transport time of 13 d was required to flush preferential flow paths in Peltandra hummocks; hydrologic turnover of the volumetrically dominant matrix pores (0.53 cm super(3) cm super(-3)) was apparently much slower. Based on porewater sampler design and hydrological principles, we suggest that N sub(2)-purged tension solution samplers and diffusion equilibrators preferentially sample porewater from macropore and matrix domains, respectively. Dissolved ammonium and orthophosphate concentrations were three-fold higher in matrix pores compared to macropores, which is consistent with our finding that more rapid hydrological flushing occurred in macropores compared to matrix pores. Further evaluation of porewater sampler designs in macroporous sediment is needed to improve studies of hydrologic transport and biogeochemical cycling in wetlands.
AN: 3831481
179 of 1521
TI: Carbon cycling in mesohaline Chesapeake Bay sediments 1: POC deposition rates and mineralization pathways
AU: Roden,-E.E.; Tuttle,-J.H.; Boynton,-W.R.; Kemp,-W.M.
AF: Dep. Biol. Sci., Univ. Alabama, Box 870344, Tuscaloosa, AL 35487-0344, USA
SO: J.-MAR.-RES. 1995 vol. 53, no. 5, pp. 799-819
LA: English
ER: M (Marine)
AB: Organic carbon cycling in sediments at two locations in the mesohaline Chesapeake Bay was analyzed using available data on sediment sulfate reduction, sediment oxygen consumption, and particulate organic carbon (POC) deposition and burial. Estimates of POC deposition based on the sum of integrated sediment metabolism and POC burial compared well with direct estimates derived from chlorophyll-a collection rates in mid-water column sediment traps. The range of POC deposition estimates (15-31 mol C m super(-2) yr super(-1)) accounted for a large fraction (36-74%) of average annual net primary production in the mesohaline Bay. The difference between rates of POC deposition and permanent burial indicated that 70-85% of deposited carbon is mineralized on the time scale of a year. Carbon mineralization through sulfate reduction accounted for 30-35% of average net primary production, and was likely responsible for 60-80% of total sediment carbon metabolism. Oxidation of reduced sulfur accounted for a large but quantitatively uncertain portion of SOC in mid-Bay sediments. Our results highlight the quantitative significance of organic carbon sedimentation and attendant anaerobic sediment metabolism in the carbon cycle of a shallow, highly productive estuary.
AN: 3828162
180 of 1521
TI: Overestimation of heterotrophic bacteria in the Sargasso Sea: Direct evidence by flow and imaging cytometry
AU: Sieracki,-M.E.; Haugen,-E.M.; Cucci,-T.L.
AF: Bigelow Lab. Ocean Sci., P.O. Box 475, McKown Point, W. Boothbay Harbor, ME 04575, USA
SO: DEEP-SEA-RES.-I-OCEANOGR.-RES.-PAP. 1995 vol. 42, no. 8, pp. 1399-1409
LA: English
ER: M (Marine)
AB: Accurate measurements of bacterial biomass in the ocean are needed for modeling marine microbial food webs and global biogeochemical cycling. We present direct evidence that previous estimates of heterotrophic bacteria biomass in the oligotrophic ocean are confounded by the presence of the abundant photosynthetic procaryote, Prochlorococcus. The chlorophyll autofluorescence of these photosynthetic bacterial cells is very faint and fades rapidly under epifluorescence microscopy. Detection and enumeration of these cells thus far has almost exclusively been by flow cytometry. Using a cooled, charge-coupled device (CCD) camera we were able to image these cells for direct biovolume measurements. A double-exposed image of DAPI-stained Prochlorococcus cells shows that they are indistinguishable from heterotrophic bacteria in standard slide preparations. At two Sargasso Sea stations Prochlorococcus could cause an overestimation of surface (top 150 m) integrated heterotrophic bacterial biovolume (biomass) of 18 and 22% determined by standard microscope methods. At the subsurface chlorophyll maximum Prochlorococcus was 33 and 43% of the heterotrophic bacterial biovolume (biomass) at these stations. Prochlorococcus cell size increased from 0.05 mu m super(3) in the surface mixed layer to about 0.2 mu m super(3) below 100 m, confirming previous interpretations of flow cytometric light scatter measurements. Shifting biomass from the heterotrophic bacteria pool to the primary producer compartment has significant implications for ecosystem structure and trophic transfer in marine food webs.
AN: 3828059
181 of 1521
TI: Economics, volcanoes, and Phanerozoic revolutions
AU: Vermeij,-G.J.
AF: Dep. Geol., Univ. California Davis, Davis, CA 95616-8605, USA
SO: PALEOBIOLOGY 1995 vol. 21, no. 2, pp. 125-152
LA: English
ER: M (Marine)
AB: Two intervals of the Phanerozoic stand out as times of biosphere-scale revolution in the sense that biogeochemical cycles came under increased control by organisms. These are the early Paleozoic (extending from just before the Cambrian to the Middle Ordovician, a duration of about 100 m.y.), characterized by the appearance of predators, burrowers, and mineralized skeletons, and by the subsequent diversification of planktonic animals and suspension-feeders: and the later Mesozoic (latest Triassic to mid-Cretaceous, a duration of somewhat more than 100 m.y.), marked by a great diversification of predators and burrowers and by the rise of mineralized planktonic protists. This paper explores the economic conditions that make such revolutions possible. I argue that opportunities for innovation and diversification are enhanced when raw materials and energy are supplied at increasing rates, or when organisms gain greater access to these commodities through rising temperatures and higher metabolic rates. Greater per capita availability of resources enables populations to grow; lessens or alters ecological constraints on functional improvement; makes possible the evolution of high metabolic rates (large incomes), which in turn permit improvement in each of several otherwise incompatible functions; and favors the establishment and spread of daughter species arising through founder speciation. Reductions in productivity reinforce adaptational constraints and may bring about extinctions. Massive submarine volcanism, together with its associated phenomena of warming, sea-level rise, and widening of warm-weather zones, is proposed to be the chief extrinsic trigger for the Phanerozoic revolutions. The later Mesozoic was characterized by continental rifting, which accompanied massive submarine volcanic eruptions that produced large quantities of nutrients and carbon dioxide. This activity began in the Late Triassic and peaked in the mid- to Late Cretaceous. The Early Cambrian was also a time of rifting and may likewise have been marked by large-scale submarine volcanism. Continental and explosive volcanism, weathering, and upwelling are other potential means for increasing evolutionary opportunity, but their effects are either local or linked directly or indirectly with cooling. Intense chemical weathering in the Early Cambrian, however, may have contributed to the early Paleozoic revolution. The extrinsic stimulus was greatly amplified through positive feedback by the evolution of higher metabolic rates and other means for acquiring, trading, retaining, and recycling resources more rapidly and from a wider range of environments. Because these novelties usually require a high and predictable supply of resources, their evolution is more likely when extrinsically controlled supplies increase rather than when per capita availability is low. In the view adopted here, the microevolutionary and microeconomic market forces of competition and natural selection operate against a backdrop of macroeconomic supply and demand. Resources are under both extrinsic and intrinsic control. Positive and negative feedbacks link processes at the micro- and macroeconomic levels. This view complements the genealogical and hierarchical conception of evolution by emphasizing that the pattern of descent is influenced by resources and by market forces operating at all scales of space and time.
AN: 3828046
182 of 1521
TI: Phosphate transfer between microbial size-fractions in Villefranche Bay (N. W. Mediterranean Sea), France in autumn 1992
AU: Dolan,-J.R.; Thingstad,-T.F.; Rassoulzadegan,-F.
AF: Observ. Sci. l'Univers., Univ. Paris IV/INSU/CNRS URA 716, Stn. Zool., B.P. 28, F-06230 Villefranche-Sur-Mer, France
CO: International Symposium on Nutrient Dynamics in Coastal and Estuarine Environments, Helsingoer (Denmark), 13-16 Oct 1993
SO: OPHELIA 1995 vol. 41, pp. 71-85
LA: English
ER: M (Marine); B (Brackish)
AB: Turnover time of orthophosphate, uptake of phosphate into particulate size-fractions (0.2-1, 1-5, 5-10, > 10 mu m), and subsequent release from size-fractions were examined using super(32)P, in samples from surface waters of Villefranche Bay during the autumnal erosion of the thermocline. Turnover time of orthophosphate increased from 1.6 h in early October to 58 h in December. Throughout the study period, total uptake was dominated (50-68%) by the smallest size-fraction (0.2-1 mu m) presumably corresponding to auto- and heterotrophic bacteria as it contained little chlorophyll a. Among the size-fractions > 1 mu m, representing eucaryotic phytoplankton uptake, the erosion of the thermocline was accompanied by a shift from the total dominance of uptake by the 1-5 mu m fraction (98%) toward an increasing contribution from the > 10 mu m fraction ( similar to 0 to 50%). In cold chase experiments, release of super(32)P from the size-fractions which dominated uptake (0.2-1 mu m & 1-5 mu m), was relatively slow ( less than or equal to 1% h super(-1)) indicating long turnover times in particulate fractions; transfer to larger size-fractions was undetectable. When the concentration of oligotrich ciliates (predators of organisms 1-6 mu m in size) was artifically increased, labeled super(32)P declined in particulate fractions and increased in the pool of inorganic suggesting a low P retention efficiency.
AN: 3827981
183 of 1521
TI: Bio-volatilization of polonium: Results from laboratory analyses
AU: Hussain,-N.; Ferdelman,-T.G.; Church,-T.M.; Luther,-G.W.,III
AF: Coll. Marine Stud., Univ. Delaware, Newark, DE 19716, USA
SO: AQUAT.-GEOCHEM. 1995 vol. 1, no. 2, pp. 175-188
LA: English
ER: F (Freshwater)
AB: Polonium, like other elements in the Group VI oxygen series (S, Se, Te), has the potential to form volatile alkyl derivatives. This may be evident in its pervasive radioactive excesses in the atmosphere and coastal waters, and its deficiency in surface open ocean waters. We present evidence for the formation of volatile polonium species. The first evidence comes from duplicating experiments that proved the existence of volatile tellurium, its Group VI congener. Cultures of bread mold at room temperature spiked with polonium tracers showed a significant and reproducible loss of about 0.5% per day of volatile polonium species. In another set of experiments, between 30-50% loss of super(210)Po was observed from Floridan groundwater when nitrogen was bubbled through it over durations of 5-30 minutes. Polonium volatility is highly relevant for biogeochemical studies because it may provide a natural radiochemical tracer for recycling of similar volatile sulfur and other Group VI metal species between the geosphere, atmosphere, and hydrosphere.
AN: 3827919
184 of 1521
TI: On photosynthesis, biotic balance and the trophic structure of marine benthic biota.
OT: O fotosinteze, bioticheskom balanse i troficheskoj strukture morskoj donnoj bioty
SO: FEEDING-OF-MARINE-INVERTEBRATES-IN-DIFFERENT-VERTICAL-AND-LATITUDINAL-ZONES.#PITANIE-MORSKIKH-BESPOZVONOCHNYKH-V-RAZNYKH-VERTIKAL'-NYKH-I-SHIROTNYKH-ZONAKH. Kuznetsov,-A.P.;Sokolova,-M.N.-eds. MOSKVA-RUSSIA IORAN 1993 pp. 7-22
NT: Incl. bibliogr.: 40 ref.
LA: Russian
ER: M (Marine)
AB: The author considers the evolution and role of photosynthesis as a perfect mechanism of solar radiation energy utilization and of producing initial living matter of the biosphere and as a planetary biogeochemical factor responsible for the origination and existence of the present-day state of the earth's surface geosystem including its biosystem.
AN: 3827910
185 of 1521
TI: Sources and cycling of organic matter in Lake Superior: A stable isotopic assessment
AU: Ostrom,-N.E.; Bell,-E.M.; Long,-D.T.
AF: Environ. Geosci. Program, Dep. Geol. Sci., 206 Nat. Sci., Michigan State Univ., East Lansing, MI 48824-1115, USA
CO: 38. Conference of the International Association for Great Lakes Research, East Lansing, MI (USA), 28 May-1 Jun 1995
SO: PROCEEDINGS-OF-THE-38TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-OF-GREAT-LAKES-RESEARCH. 2200-BONISTEEL-BOULEVARD,-ANN-ARBOR,-MI-48109-2099-USA INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH 1995 pp. 73-74
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: In June of 1994 a series of water column and sediment samples were collected at three stations within the Chefswet Basin of Lake Superior to evaluate the sources and cycling of organic matter within this system. This study presents data on the delta super(15)N and delta super(13)C of sedimentary and suspended particulate organic matter and dissolved inorganic matter. Water column temperatures were close to 4 degree C at all stations and the presence of a thermocline was observed at only the shallow station. Low concentrations of particulate material and fluorometer readings suggested that primary production was reduced at this time. Carbon isotope values for seston varied only slightly with station and depth and values ranged between -27.3 and 26.2ppt Average sediment delta super(13)C and delta super(15)N values of -26.8 and 5.2ppt, respectively, were similar to water column material and consistent with a phytoplankton origin. Seston delta super(15)N values were more variable than delta super(13)C and ranged between 0.4 and 6.9ppt. The delta super(15)N of nitrate ranged between -5.0 and 0.9ppt and was markedly depleted in super(15)N relative to seston. These are some of the lowest delta super(15)N values reported for nitrate in aquatic systems. We content that phytoplankton release super(15)N depleted dissolved organic matter and that upon mineralization and nitrification, DOM is the primary source of nitrate in Lake Superior.
AN: 3825518
186 of 1521
TI: Seasonal trends in the natural abundances of carbon and nitrogen stable isotopes in the east basin of Lake Ontario
AU: Leggett,-M.F.; Servos,-M.R.; Hesslein,-R.; Johannsson,-O.; Dixon,-D.G.
AF: Great Lakes Lab. Fish. Aquat. Sci., 867 Lakeshore Rd., Burlington, ON, Canada
CO: 38. Conference of the International Association for Great Lakes Research, East Lansing, MI (USA), 28 May-1 Jun 1995
SO: PROCEEDINGS-OF-THE-38TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-OF-GREAT-LAKES-RESEARCH. 2200-BONISTEEL-BOULEVARD,-ANN-ARBOR,-MI-48109-2099-USA INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH 1995 p. 73
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Selective discrimination in biota between naturally occurring stable isotopes of carbon super(13)C and super(12)C, and nitrogen super(14)N and super(15)N, in biochemical reaction kinetic has been exploited in studies of food web dynamics in different ecosystems. Conclusions of these studies often assume that observed relative ratios of these stable isotope pairs are solely a function of the total reaction kinetics involved in the transfer of energy through a food chain. It is also assumed that the ratio of stable isotope pairs at the bottom of the food chain remains constant. Environmental conditions have been shown to affect the ratio of stable isotopes found in primary producers, and seasonal cycling has been observed in source carbon (dissolved inorganic carbon, DIC) in aquatic ecosystems. A seasonal fluctuation of the super(13)C/ super(12)C ratio is shown in DIC, particulate organic carbon (POC), Diacyclops thomasi, and Bosmina longirostris at a site in the east basin and a mid-lake site. When possible super(15)N/ super(14)N was also determined for each sample and the results of this analysis are plotted.
AN: 3825517
187 of 1521
TI: Records of ecosystem changes in the isotope signatures of organic matter in Great Lakes cores
AU: Eadie,-B.J.; Lansing,-M.B.; Robbins,-J.A.
AF: NOAA/Great Lakes Environ. Res. Lab., 2205 Commonwealth Blvd., Ann Arbor, MI 48109, USA
CO: 38. Conference of the International Association for Great Lakes Research, East Lansing, MI (USA), 28 May-1 Jun 1995
SO: PROCEEDINGS-OF-THE-38TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-OF-GREAT-LAKES-RESEARCH. 2200-BONISTEEL-BOULEVARD,-ANN-ARBOR,-MI-48109-2099-USA INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH 1995 p. 73
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Over the past 25 years, nutrient abatement practices have reduced the loading of phosphorus dramatically although nitrogen inputs and concentrations continue to increase. Monitoring data from the lakes cover this time period in some detail, but the records from before the late 1960s must come from signals in the sediments. In the lower lakes (Erie and Ontario), the delta super(13)C of organic matter reaches its heaviest value in the early 1970s and then decreases as nutrient reduction went into effect and primary production decreased. This effect is much less pronounced in the upper lakes. delta super(15)N of the organic matter in the lower lakes increases dramatically from a background value of 2-3ppt to a recent value of 10ppt. Again this change is significantly less in the upper lakes. Although there has been a major increase in N loads and sources of N (fertilizer and atmospheric), it appears that most of the isotopic shift recorded in sediments is due to denitrification in Lake Erie, with subsequent transport of this signal downstream to Lake Ontario. The delta super(15)N shift in the sediments of the lower lakes began soon after 1850, which corresponds to the period of clearcutting and beginning of agriculture in the basin.
AN: 3825516
188 of 1521
TI: Cycling of radionuclides in Lake Erie surface waters: The key role of microzooplankton grazing
AU: Twiss,-M.R.; Campbell,-P.G.C.; Auclair,-J.-C.
AF: INRS-Eau Univ. Quebec, C.P. 7500, Ste-Foy, QC G1V 4C7, Canada
CO: 38. Conference of the International Association for Great Lakes Research, East Lansing, MI (USA), 28 May-1 Jun 1995
SO: PROCEEDINGS-OF-THE-38TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-OF-GREAT-LAKES-RESEARCH. 2200-BONISTEEL-BOULEVARD,-ANN-ARBOR,-MI-48109-2099-USA INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH 1995 pp. 68-69
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Recent measurements in the Great Lakes reveal very low levels of dissolved trace metals. Current approaches to estimating trace metal concentrations and residence times in the water column are based on surface complexation modelling (SCM). The majority of particles in pelagic systems are biotic - among the most productive are the picoplankton (bacteria and algae, 0.2-2 mu m) which have a high potential to scavenge dissolved trace metals. The ecological fate of this plankton involves consumption by microzooplankton (2-200 mu m; e.g., flagellates, ciliates, rotifers). This grazing might reasonably be expected to convert some trace metals from the particulate to dissolved phase, and to increase the availability of metal-complexing organic ligands in the dissolved phase. In turn, this would serve to increase trace metal residence times and concentrations in surface waters in a manner unaccountably for by current predictive models based on SCM. Evidence of this activity is presented from a field study on the fate of radiolabelled picoplankton added to the natural plankton community of pelagic Lake Erie. Trace metal fates were followed using gamma-emitting radionuclides (Cs-137, Cd-109, Zn-65 and Gd-153) representing a range of chemical behaviours.
AN: 3825509
189 of 1521
TI: Cycles in Lake Malawi
AU: Patterson,-G.; Allison,-E.H.
AF: Nat. Resour. Inst., NRL, Chatham Maritime Kent, ME4 4TB, UK
CO: 38. Conference of the International Association for Great Lakes Research, East Lansing, MI (USA), 28 May-1 Jun 1995
SO: PROCEEDINGS-OF-THE-38TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-OF-GREAT-LAKES-RESEARCH. 2200-BONISTEEL-BOULEVARD,-ANN-ARBOR,-MI-48109-2099-USA INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH 1995 p. 56
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: The seasonal wind-induced cycle of mixing has a strong influence on biological production in Lake Malawi. Periods of increased mixing result in increases in nutrient availability to photosynthesising phytoplankton in the epilimnion, leading to higher primary production and increases in available food to, and production of, herbivorous zooplankton. Engraulicycpris sardella and Chaoborus larvae, which are important predators on the zooplankton, also show marked seasonality of production which coincides with the seasonal pattern of the lower trophic levels. This is an example of the dependence of biological production on nutrient availability and shows many of the characteristics of "bottom-up" control. There is no evidence to suggest that the seasonal production cycles are significantly dampened up the food chain, at least to tertiary producers and we suggest that production is controlled primarily by food supply.
AN: 3825250
190 of 1521
TI: Comparison of phosphorus concentration and turnover rates in lakes Erie, Huron, and Michigan with those of the East African Great Lake Victoria
AU: Lehman,-J.T.
AF: Dep. Biol. and Cent. Great Lakes Aquat. Sci., Nat. Sci. Bldg., Univ. Michigan, Ann Arbor, MI 48109, USA
CO: 38. Conference of the International Association for Great Lakes Research, East Lansing, MI (USA), 28 May-1 Jun 1995
SO: PROCEEDINGS-OF-THE-38TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-OF-GREAT-LAKES-RESEARCH. 2200-BONISTEEL-BOULEVARD,-ANN-ARBOR,-MI-48109-2099-USA INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH 1995 p. 54
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: North American Great Lakes Erie, Huron, and Michigan exhibit almost unmeasurably low concentrations of SRP with turnover times in epilimnion and metalimnion of only a few minutes. This well known situation in the North American lakes compares with turnover times of 5 days in the pelagic region of Lake Victoria, where SRP concentrations can be 1 micromolar. Nonetheless, at its outflow as the Nile, SRP concentrations are reduced and turnover times fall to minutes, similar to North American Great Lake levels. The changes in P economy of Lake Victoria are associated with algal biomass increases in shallower water. Model formulations of the turnover dynamics and their relationship to biomass levels are investigated for these tropical and temperate Great Lakes.
AN: 3825244
191 of 1521
TI: A model-assisted technique for computing "effective" phosphorus loading from bottom sediments
AU: Martin,-S.C.
AF: Dep. Civ. Environ. Eng., Youngstown State Univ., Youngstown, OH 44555, USA
CO: 38. Conference of the International Association for Great Lakes Research, East Lansing, MI (USA), 28 May-1 Jun 1995
SO: PROCEEDINGS-OF-THE-38TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-OF-GREAT-LAKES-RESEARCH. 2200-BONISTEEL-BOULEVARD,-ANN-ARBOR,-MI-48109-2099-USA INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH 1995 p. 39
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: When phosphorus loading reduction measures are implemented in a lake, the water quality response is often delayed by recycling of phosphorus stored in the bottom sediments. Sediment phosphorus recycling may continue to retard recovery of the water column even when sediments are acting as a net sink of phosphorus. The importance of sediment loading may be difficult to quantify in such cases. In this study, a new quantity called "effective" sediment phosphorus loading was developed for this purpose. The "effective" sediment loading is defined as the difference between the net rate of phosphorus exchange at the sediment-water interface at any given time during the recovery and the exchange rate when the system has reached steady-state. If an adequate data base is available to calibrate a mass-balance model for total phosphorus in the lake, then the model can be applied to estimate both quantities. This technique was applied to forecast the role of sediment phosphorus recycle in delaying water quality improvements in St. Albans Bay, Lake Champlain (VT), following a 90% reduction in point source loading. It was predicted that the "effective" sediment phosphorus loading will decline from 42 kg/d (50% of total load) in 1993 to 8.4 kg/d (22% of total load) by the year 2015.
AN: 3825206
192 of 1521
TI: Plankton productivity and biomass in the western Equatorial Pacific: Biological and physical controls
AU: Mackey,-D.J.; Parslow,-J.; Higgins,-H.W.; Griffiths,-F.B.; O'-Sullivan,-J.E.
AF: NRO Div. Oceanogr., GPO Box 1538, Hobart, Tas., Australia
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 2-3, pp. 499-533
LA: English
ER: M (Marine)
AB: During October 1990 in the western Equatorial Pacific, from 5 degree S to 5 degree N along 155 degree E, the isothermal and isopycnal lines (near 150 m) domed upwards, surface temperatures were high (29.5-30 degree C), surface salinites were low (33.8-34.2), SST anomalies were <0.5 degree C between 120 degree E and 160 degree E, and the westward flowing SEC was well developed. These conditions are typical of non-ENSO conditions. An eastward flowing surface current was observed that was probably the result of a westerly wind burst. Between 5 degree S and 5 degree N, the barrier layer was much thicker south of the equator and the thickness of the barrier layer varied from 88 m at 2 degree S to 6 m at 1 degree N. Nitrate and nitrite were not detected in surface waters, but phosphate and silicate were present at concentrations of about 0.15 mu M and 1.5 mu M, respectively. Nitrate was always present at the deep chlorophyll maximum (DCM), which varied in depth from about 74 to 96 m. The distribution of chlorophyll a (plus divinyl-chlorophyll a) about the equator was distinctly bimodal, with the highest values (0.4 mu g l super(-1)) occurring 2 degrees either side of the equator. Depth integrated values ranged from 23 to 32 mg m super(-2), and despite the very different oceanographic conditions these values are similar to those found in the nutrient-rich waters of the central and eastern equatorial Pacific. However, primary production estimates ranged from 96 to 241 mg C m super(-2) day super(-1) (8.0 to 20.1 mmol C m super(-2) day super(-1)), and these are much lower than previous rates reported for the central and eastern equatorial Pacific. The vertical distribution of cyanobacteria varied markedly from 5 degree S to 5 degree N. North of the equator, the concentrations were fairly high and uniform in the upper water column whereas, south of the equator, surface concentrations were low with a subsurface maximum. This distribution of cyanobacteria suggests that there was transient enrichment north of the equator but not to the south. The low salinity surface layer was highly oligotrophic and appeared to be effectively isolated the subsurface fluxes of nitrate or dissolved inorganic carbon (DIC). Productivity in the surface layer seemed to be limited by the supply of nutrients, although there were indications that transient nutrient enrichment of surface waters may have occurred north of the equator. In the DCM it appeared to be limited by light. Integrated primary production and cyanobacterial cell counts were elevated north of the equator where the barrier layer was thin. The isolation of the surface waters from the deeper waters that were enriched in nutrients and DIC caused the pCO sub(2) values in surface waters to be in near equilibrium with the atmosphere. Despite a strong N-S gradient in the thickness of the barrier layer, the nitracline and upper boundary of the deep chlorophyll maximum were independent of latitude and occurred at approximately 60-70 m, close to the depth of 10% light penetration.
AN: 3823962
193 of 1521
TI: Sulfate reduction rates and low molecular weight fatty acid concentrations in the water column and surficial sediments of the Black Sea
AU: Albert,-D.B.; Taylor,-C.; Martens,-C.S.
AF: Curriculum Mar. Sci., Univ. North Carolina, Chapell Hill, NC 27599, USA
SO: DEEP-SEA-RES.-I-OCEANOGR.-RES.-PAP. 1995 vol. 42, no. 7, pp. 1239-1260
LA: English
ER: M (Marine)
AB: Sulfate reduction rates and concentrations of low molecular weight organic acids were measured in the water column and surficial sediments at two sites in the central Black Sea. Water column sulfate reduction rates were much lower than previously reported. The highest rate measured was 3.5 nM/day and on a depth integrated basis values of 1.2 and 0.22 mmol/m super(2)/day were obtained for the two sites. Sediment sulfate reduction rates were within the ranges previously reported but were higher than some for comparable abyssal sites. Rates were about 21 mu M/day in the flocculent layer at the sediment-water interface, decreasing to 2-3 mu M/day at 20 cm depth. On an areal, depth integrated basis, rates at the two sites were 1.45 and 1.29 mmol/m super(2)/day. Thus, the water column and sediments have comparable areal rates, but on a volume basis the sediment rates are several thousand times higher than the water column rates. Organic acid concentrations in the anoxic Black Sea water column were surprisingly high, reaching several mu M in some cases. One deep sample contained 60 mu M acetate. Lactate, acetate and formate were the only acids detected in the water column. Some propionate was seen in sediment porewaters. Apparent turnover times of the organic acids in the water column, calculated for utilization solely by sulfate reducing bacteria, are tens to hundred of years. This suggests that sulfate reduction rates in the water column were not limited by organic substrate supply. In the sediments, apparent acid turnover times calculated in this way are generally less than one day, suggesting that sulfate reduction may be limited to by the supply of these substrates through fermentation reactions.
AN: 3823926
194 of 1521
TI: Spatial distribution and trophic transfer of lead in Lake Superior
AU: Beals,-T.M.; Long,-D.T.; Ostrom,-N.E.
AF: Dep. Geol. Sci., Michigan State Univ., East Lansing, MI 48824, USA
CO: 38. Conference of the International Association for Great Lakes Research, East Lansing, MI (USA), 28 May-1 Jun 1995
SO: PROCEEDINGS-OF-THE-38TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-OF-GREAT-LAKES-RESEARCH. 2200-BONISTEEL-BOULEVARD,-ANN-ARBOR,-MI-48109-2099-USA INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH 1995 p. 102
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Large lakes are composed of a number of physically distinct compartments, including: (1) dissolved components in the water column, (2) suspended solids, (3) sediments, and (4) pore waters. Chemical gradients within and between these compartments will affect the trophic transfer of contaminants in the biological community. Within a depositional basin spatial gradients in a contaminant's settling flux through the water column, rate of accumulation in the sediment, and diagenetic flux have implications on its uptake by benthic organisms and, subsequently, its fate in the environment. Water column, suspended sediment, sediment column, pore water, and biological samples were collected from Lake Superior using the R/S Clelia and R/V Edwin Link. Water column and pore water samples were analyzed by Graphite Fumace Atomic Absorption Spectrophotometry (GF/AAS). Solid phase samples were subjected to a HNO sub(3) microwave digestion and the leachate analyzed by GF/AAS. Preliminary results indicate that dissolved Pb concentrations in both the water column and pore waters are less than 1.0 g/L. Concentrations of Pb in both the benthic nepheloid and fluff layers are higher than that in the sediment column with the fluff being greater than the nepheloid. Concentration profiles of Pb in the sediment column exhibit anthropogenic loadings similar to ones determined by previous studies. However, the total anthropogenic Pb inventories are greater than previous studies and the peak concentration occurs at a greater depth due to continued sediment accumulation between the time of sampling. Sediment accumulation of Pb continues to decrease to the present day.
AN: 3823779
195 of 1521
TI: Biogeochemical origin of delta super(34)S isotopic signatures in a prairie marsh
AU: Cornwell,-J.C.; Neill,-C.; Stevenson,-J.C.
AF: Horn Point Environ. Lab., Univ. Maryland Cent. Environ. Estuar. Stud., Cambridge, MD 21613-0775, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI.-J.-CAN.-SCI.-HALIEUT.-AQUAT. 1995 vol. 52, no. 8, pp. 1816-1820
LA: English
ER: F (Freshwater)
AB: Sulfur isotope ratios were determined in a prairie marsh at Delta, Manitoba, Canada, to determine whether organic matter produced in the marsh had distinctive isotopic signatures. High sulfate levels in sediments from the Delta Marsh arise from high salt concentrations in soils. Sulfate reduction is the major anaerobic metabolic pathway in this sediment system and sulfate diffused into sediment both from deeper soil horizons and from overlying water. Surface water delta super(34)S-SO sub(4) super(2-) values of 15 plus or minus 1ppt increased to a maximum of almost 40ppt in deeper sediment horizons, in marked contrast to sediment pore water delta super(34)S-H sub(2)S values of 2 plus or minus 4ppt. The high degree of discrimination between delta super(34)S in sulfate and in hydrogen sulfide is similar to that found in brackish and marine ecosystems.
AN: 3823740
196 of 1521
TI: Seasonal and lateral variations in carbon chemistry of surface water in the eastern Equatorial Pacific during 1992
AU: Wanninkhof,-R.; Feely,-R.A.; Atwood,-D.K.; Berberian,-G.; Wilson,-D.; Murphy,-P.P.; Lamb,-M.F.
AF: Atl. Oceanogr. and Meteorol. Lab., Miami, FL 33149, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 2-3, pp. 387-409
LA: English
ER: M (Marine)
AB: During the (boreal) spring and fall of 1992 the NOAA Ocean-Atmosphere Carbon Exchange Study did an intensive survey of upper water column (<1000 m) chemistry in the eastern equatorial Pacific from 110 degree W to 170 degree W. The spring-time conditions were influenced by an El Nino that had disappeared before the fall cruises. This contributed to a large seasonal contrast in surface temperature, carbon and nutrient concentrations, and thermocline depth. Nitrate, total inorganic carbon, and fugacity of CO sub(2) values were significantly lower in the spring, while sea surface temperatures south of the equator were higher. The seasonal change in surface water chemistry at the equator is due to changes in upwelling of nutrient and carbon enriched water. Oxygen and CO sub(2) anomalies at the surface point to approximately a three-fold increase in upwelling of thermocline water in the fall compared to the spring. The large-scale spatial variations in the surface chemistry patterns remained unchanged between spring and fall. There was a westward decrease in surface-water carbon and nitrate concentrations and a strong north to south asymmetry with higher carbon and nitrate values south of the equator. This pattern is attributed to input of carbon and nutrients with the South Equatorial Current from the east. Using velocities obtained from surface drifters tracks, along with reasonable gas exchange estimates, and a "Redfield analysis" to account for export biological production, this westward decrease in carbon and nutrients can be quantitatively accounted for in the region from 0 to 3 degree S and 110 degree W to 140 degree W in the spring. In the fall the calculated concentration decrease is greater than observed, which is attributed to input from local equatorial upwelling along the pathway of water transit.
AN: 3822077
197 of 1521
TI: The role of pH measurements in modern oceanic CO sub(2)-system characterizations: Precision and thermodynamic consistency
AU: Clayton,-T.D.; Byrne,-R.H.; Breland,-J.A.; Feely,-R.A.; Millero,-F.J.; Campbell,-D.M.; Murphy,-P.P.; Lamb,-M.F.
AF: Dep. Mar. Sci. Univ. South Florida, St. Petersburg, FL 33701, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 2-3, pp. 411-429
LA: English
ER: M (Marine)
AB: In May 1992, surface seawater samples were collected along an equatorial transit (130 to 100 degree W) and analyzes for total hydrogen ion concentration (expressed as spectrophotometric pH sub(T)) total dissolved inorganic carbon (coulometric C sub(T)), and total alkilinity (potentiometric A sub(T) and spectrophotometric A sub(T)). This data set, which presents a striking view of the chemical signature of tropical instability waves, is also unusual in that its "overdetermination" of the CO sub(2)-system in seawater includes both potentiometric A sub(T) data and the first spectrophotometric A sub(T) data collected at sea using a double-wavelength, one-step acid addition method. Our data set indicates that spectrophotometric A sub(T) measurements (A sub(Tspec)) are both precise ( plus or minus 1.8 mu mol/kg) and accurate; the mean observed difference between A sub(Tspec) and A sub(T) obtained potentiometrically in this study (A sub(Tpot)) is 1 mu mol/kg. As only two of the three measured parameters are required to characterize the CO sub(2)-system in seawater, this analytical redundancy of our analyses (C sub(T), A sub(T), pH) afforded an opportunity to evaluate, in terms of thermodynamic consistency, a recent calibration of m-cresol purple, a pH indicator. Using various carbonic acid dissociation constants, measured parameters were combined in pairs (C sub(T)-A sub(T), pH-C sub(T), and pH-A sub(T)) to calculate a third parameter for comparison with the shipboard measurements. Depending on the selected set of carbonic acid dissociation constants, the average offset between directly measured and predicted values of A sub(T) and C sub(T) was as small as plus or minus 1 mu mol/kg. The results of this study indicate that the present 25 degree C mCP calibration, paired with the 25 degree C combined dissociation constants of Hansson and Mehrbach, produces accurate predictions of A sub(T) and C sub(T). Extensive replication of the shipboard spectrophotometric measurements made it possible to examine directly the sensitivity of derived parameters to variations or errors in input A sub(T) and pH. In accord with earlier theoretical treatments of this question, the results presented demonstrate that pH is imprecisely predicted from A sub(T) and C sub(T), whereas imprecision in measured pH-at the level typical of spectrophotometric measurements ( plus or minus 0.0004)-contributes negligibly ( plus or minus 0.3 mu mol/kg) to imprecision in derived A sub(T) and C sub(T). In view of the high precision of pH sub(Tspec) measurements and both the precision and reliability of C sub(T) measurements (supported by the use of certified SIO reference materials) pH sub(Tspec) and C sub(Tcoul) constitute a particularly useful pair of parameters for shipboard study of the oceanic carbon dioxide system. The results indicate, as well, that the A sub(T)-pH sub(Tspec) pairing is of particular interest in ocean regions where simple A sub(T) vs salinity relationships are observed. In light of recent advances, the role of pH measurements in CO sub(2)-system characterizations should be re-evaluated. Spectrophotometric measurements of pH have much to contribute in documenting the oceans' evolving response to anthropogenic CO sub(2).
AN: 3822075
198 of 1521
TI: Mesozooplankton grazing and metabolism at the equator in the Central Pacific: Implications for carbon and nitrogen fluxes
AU: Dam,-H.G.; Zhang,-Xinsheng; Butler,-M.; Roman,-M.R.
AF: Dep. Mar. Sci., Univ. Connecticut, Groton, CT 06340-6097, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 2-3, pp. 735-756
LA: English
ER: M (Marine)
AB: Primary productivity and chlorophyll in the Equatorial Pacific are lower than expected based on ambient nutrient concentrations. We tested the hypothesis that these conditions are due to a balance between phytoplankton growth and mesozooplankton grazing. Grazing rates and biomasses of three size classes of zooplankton in the size range of 200-200 mu m were measured during March-April and October of 1992 at the equator (140 degree W). El Nino conditions prevailed in March-April, whereas in October a tropical instability wave (TIW) passed through the study area. Weight-specific pigment ingestion rates of mesozooplankton tended to be higher in March-April than in October while the opposite was the case for biomass. There were no discernible temporal trends in mesozooplankton community grazing rates in March-April, but there were changes in October associated with the passage of the TIW. Mesozooplankton grazing removed 1-9% day super(-1) of the total chlorophyll and 1-12% of the primary production within the euphotic zone. Therefore, the grazing hypothesis as stated above is rejected, although a simple chlorophyll budget suggests that grazing (mostly by microzooplankton) and phytoplankton growth are roughly in balance. Most of the phytoplankton was <2 mu m and presumably unavailable as food for mesozooplankton. If we assume that mesozooplankton only fed on >2- mu m phytoplankton, we estimate removal rates of the >2- mu m chlorophyll standing stock of up to 27% day super(-1). Another question of biogeochemical importance is the rate of the production of large diatoms. Mesozooplankton grazing could have balanced growth of the large (>20- mu m) diatoms in March-April, but not in October. From estimates of respiration and excretion based on water temperature and body size, we infer that: (1) >80% of the carbon ingested by mesozooplankton is not phytoplankton; (2) mesozooplankton excretion supports <7% of the nitrogen demands of phytoplankton; (3) the flux of carbon passing through the mesozooplankton would be equivalent to 23% of the primary production; (4) mesozooplankton fecal carbon could account for 100% of the sinking POC flux in this region. Finally, a simple food chain analysis suggests that a significant fraction of the microzooplankton production probably passes through mesozooplankton.
AN: 3821988
199 of 1521
TI: Surface pH and pCO sub(2) distributions in the Bellingshausen Sea, Southern Ocean, during the early Austral summer
AU: Bellerby,-R.G.J.; Turner,-D.R.; Robertson,-J.E.
AF: Dep. Mar. Chem. and Geochem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 4-5, pp. 1093-1107
LA: English
ER: M (Marine)
AB: Measurements of the carbon dioxide system (pH, pCO sub(2)) from the Bellingshausen Sea, Southern Ocean are discussed in relation to varying biological activity and hydrography. pH was determined using on-line indicator spectrophotometry and varied between 7.65 and 7.85 (at 25 degree C) and between 8.04 and 8.25 at in situ temperatures. Except for the Bransfield Strait, pCO sub(2) was below atmospheric pCO sub(2) for the duration of the cruise, with the average level being 295 plus or minus 32 mu atm (1 SE). Large mesoscale variability with no single control on the surface seawater carbon dioxide system was observed, although the majority of the study area was predominantly influenced by the hydrography of the circumpolar waters. The most significant exception being a region with high chlorophyll concentration south of the Southern Polar Front.
AN: 3820137
200 of 1521
TI: Spatial variability of inorganic nutrients in the marginal ice zone of the Bellingshausen Sea during the Austral spring
AU: Whitehouse,-M.J.; Priddle,-J.; Woodward,-E.M.S.
AF: Br. Antarct. Surv., NERC, High Cross, Madingley Rd., Cambridge CB3 0ET, UK
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 4-5, pp. 1047-1058
LA: English
ER: M (Marine)
AB: Data on nutrients (nitrate, nitrite, ammonium, phosphate, silicate), biogenic-silica and chlorophyll a concentrations were collected along a south-to-north transect through the marginal ice zone of the Bellingshausen Sea during the Austral spring of 1992. There was a marked gradient in near-surface ( less than or equal to 100 m) concentrations from the most southerly occupied station (70 degree 15'S, 85 degree 07'W) to the northernmost (67 degree 30'S, 85 degree 00'W). Chlorophyll a concentrations increased from similar to 0.1 at the most southerly station to >4.0 mg m super(-3) in the north. A simple ice-melt model suggests that only a proportion of the previous winter's sea-ice had melted in the study area. The impact of this ice-melt on nutrient concentrations was trivial. Predicted time-scales of nutrient removal by phytoplankton growth varied for the three nutrients. Nitrogen uptake appeared to be underestimated with respect to phosphorous, consistent with measurements of nitrogen preference from the same cruise. Silicate use appeared to have started later than nitrogen or phosphorus uptake, indicative of species succession in the phytoplankton.
AN: 3820134
201 of 1521
TI: A biogeochemical study in the Bellingshausen Sea: Overview of the STERNA 1992 expedition
AU: Turner,-D.R.; Owens,-N.J.P.
AF: Dep. Anal. and Mar. Chem., Goeteborg Univ. and Chalmers Univ. Technol., S-412 96 Goeteborg, Sweden
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 4-5, pp. 907-932
LA: English
ER: M (Marine)
AB: A general overview and background of a two-ship study to examine biogeochemical fluxes in the marginal ice-zone of the Bellingshausen Sea (65-70 degree S; 80-87 degree W), SE Pacific sector of the Southern Ocean is presented. The major feature studied was an intense band of chlorophyll that was found geographically close to a receding ice-edge. However, the bloom appeared not to be a result of a shallow mixed layer caused by ice-melt stabilisation, but rather associated with an oceanic front that coincided with the ice-edge. Details of the hydrographic conditions existing along the 85 degree W meridian from the ice-edge to open water to the north, and detailed surveys of surface hydrographic conditions are presented.
AN: 3820128
202 of 1521
TI: The impact of marginal ice zone processes on the distribution of super(210)Pb, super(210)Po and super(234)Th and implications for new production in the Bellingshausen Sea, Antarctica
AU: Shimmield,-G.B.; Ritchie,-G.D.; Fileman,-T.W.
AF: Mar. Geosci. Unit, Dep. Geol. and Geophys., Univ. Edinburgh, West Mains Rd., Edinburgh EH9 3JW, UK
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 4-5, pp. 1313-1335
LA: English
ER: M (Marine)
AB: The vertical distributions of super(210)Pb, super(210)Po and super(234)Th in both dissolved and particulate phases of seawater were measured at five stations along the 85 degree W meridian in the Bellingshausen Sea, Antarctica. Sea-ice conditions during the expedition ranged from fully ice-covered (fast ice) to open water away from the marginal ice zone. Concurrent primary productivity and algal chlorophyll measurements revealed a band of high productivity at approximately 67 degree 30'S, which remained in a rather static location during ice melt-back. Along the transect a progressive increase in removal ("scavenging") and sinking of super(210)Pb, super(210)Po and super(234)Th occurred towards the north (open water conditions). Application of a simple, irreversible scavenging model, and particulate organic carbon and organic nitrogen to radionuclide ratios measured on suspended particulate matter, allows the calculation of export production for this region. Radionuclide estimates of new production are significantly greater than those obtained by traditional sediment trap methods. This may be due to the dynamic nature (short duration and spatial variability) of algal growth in the Southern Ocean.
AN: 3820121
203 of 1521
TI: Nitrogen dynamics in the Bellingshausen Sea during the Austral spring of 1992
AU: Waldron,-H.N.; Attwood,-C.G.; Probyn,-A.; Lucas,-M.I.
AF: Dep. Oceanogr., Univ. Cape Town, Priv. Bag, Rondesbosch, Cape Town 7700, South Africa
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 4-5, pp. 1253-1276
LA: English
ER: M (Marine)
AB: A series of super(15)N experiments were conducted in the early summer of 1992 during the course of cruise 198 of R.R.S. Discovery, with a focus on the seasonal ice zone (SIZ) of the Bellingshausen Sea. Nitrogen (NO sub(3), NH sub(4) and urea) uptake was measured over the nominal euphotic zone, and size fractionation experiments of a similar nature were conducted on surface waters. The most productive zone during this study was not associated with stable ice-melt water but with a west-east oriented, haline dominated density front centred around 67.3 degree S. The pelagic bloom coincident with the area south of the front had a banded structure with chlorophyll a concentrations up to 5 mg m super(-3). The bloom was dominated by Porosira glacialis, Coscinodiscus bouvet, Thalassiosira antarctica and Phaeocystis spp. The rates of new production presented here are the first to have been made in the Bellingshausen Sea and as such can be incorporated in regional and global models relating to the sink of carbon.
AN: 3820120
204 of 1521
TI: super(13)C and super(15)N uptake by phytoplankton in the marginal ice zone of the Bellingshausen Sea
AU: Bury,-S.J.; Owens,-N.J.P.; Preston,-T.
AF: Scottish Univ. Res. and Reactor Cent., East Kilbride, Glasgow G75 0QF, UK
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 4-5, pp. 1225-1252
LA: English
ER: M (Marine)
AB: A two-ship cruise to the Bellingshausen Sea marginal ice zone (MIZ) in the Austral spring-summer 1992 enabled a detailed study of the phytoplankton dynamics during the retreat of the ice sheet. Stations were set up along a transect from within the ice sheet 70 degree S, 85 degree W to the open ocean 67 degree S, 85 degree W, and the rates of primary production and nitrogen uptake were determined in the ice and water column using in situ super(13)C and super(15)N incubation techniques. Nitrogen uptake was subdivided into components of nitrate, ammonium and urea uptake, and fractionated into <20 mu m and >20 mu m size classes. A detailed discussion of methods available for f-ratio calculations using several different data sets from this cruise are given. Varied estimates resulting from this exercise have important implications in terms of global carbon budget calculations. Productivity estimates from super(13)C and super(15)N uptake data are compared with super(14)C data, and nitrate, phosphate, chlorophyll and pCO sub(2) mass balance estimates. These data are discussed in the context of past studies in other areas of the Southern Ocean.
AN: 3820119
205 of 1521
TI: Water column and sea-ice primary production during Austral spring in the Bellingshausen Sea
AU: Boyd,-P.W.; Robinson,-C.; Savidge,-G.; William,-P.J.leB.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 4-5, pp. 1177-1200
LA: English
ER: M (Marine)
AB: The findings of a cruise to study the phytoplankton bloom dynamics associated with the marginal ice zone (MIZ) in the Bellingshausen Sea during Austral spring (November-December) 1992 are reported. Biomass and rate process measurements were carried out at stations located in the ice, ice edge and open water along the 85 degree W meridian in order to establish the productivity of the microalgae associated with sea-ice and in the water column. In addition, a series of transects along 85 degree W from sea-ice to open water conditions enabled an assessment of the development of phytoplankton populations. Low phytoplankton biomass and production were noted at ice-covered and ice-edge stations and in the open water close to the ice edge. Observations from the transects indicated no development of a classical ice edge bloom despite evidence that sea-ice had retreated more than 100 km during the study period. A modelling approach using super(14)C observations suggested that phytoplankton growth was less than the sum of the algal loss terms within this feature. An advective supply of cells therefore would be required to sustain the observed high and constant algal biomass. In addition, although this high chlorophyll feature was initially observed during brash-ice conditions, the available data suggest that it was initiated under open water conditions.
AN: 3820118
206 of 1521
TI: A biological acoustic survey in the marginal ice-edge zone of the Bellingshausen Sea
AU: Murray,-A.W.A.; Watkins,-J.L.; Bone,-D.G.
AF: Br. Antarct. Surv., High Cross, Madingley Rd., Cambridge CB3 0ET, UK
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 4-5, pp. 1159-1175
LA: English
ER: M (Marine)
AB: An acoustic survey at 38 kHz was carried out from R.R.S. Discovery in the Bellingshausen Sea from 23 November to 7 December 1992 as part of the U.K. Joint Global Ocean Flux Study (JGOFS) Southern Ocean investigations [Turner D. and N.J.P. Owens (1995) Deep-Sea Research II, 42, 907-932]. A total of 285 targets were identified and described from the chart record of the echo sounder. Mean volume backscattering strength data were collected using an echo integration system. These data are used to describe the spatial and temporal variability of krill (Euphausia superba) distribution and biomass in the marginal ice-edge zone. Krill biomass density varied from a mean of 42 g m super(-2) during the first survey phase to 20 g m super(-2) on the second survey phase. The number of small swarms detected during the second phase was greater than during the first phase. On this first survey a large swarm (2.8 km in extent) had a potential biomass of 3.7 x 10 super(4) tonnes. Some calculations are presented to show the potential impact of krill on the flux of carbon in the area of the survey.
AN: 3820117
207 of 1521
TI: Role of suspension-feeders in the exchanges at the water-sediment interface in a coastal area subject to strong tidal currents: Experimental approach
OT: Role des organismes suspensivores dans les transferts pelago-benthiques d'une zone de fort hydrodynamisme: Approche experimentale
AU: Migne,-A.; Davoult,-D.
AF: Stn. Marine URA-CNRS 1363, BP 80, 62930 Wimereux, France
SO: J.-RECH.-OCEANOGR. 1995 vol. 20, no. 1-2, pp. 9-14
LA: French
ER: M (Marine)
AB: A rich benthic community (mean biomass: 270 g m super(-2) in ash-free dry weight), exposed to strong tidal currents, is dominated by suspension-feeders. Experimental measurements of transfers of matter through nutrition, excretion and respiration of the 3 dominant species (Biothrix fragilis, Urticina felina and Alcyonium digitatum) were used to estimate carbon and nitrogen fluxes between the water and the benthic community.
AN: 3817474
208 of 1521
TI: Influence of the tube-building spionid polychaete Polydora ciliata on benthic parameters, associated fauna and transport processes
AU: Noji,-C.I.M.
AF: Inst. Fish. Mar. Biol. Univ. Bergen, Thormohlensgt 55, 5008 Bergen, Norway
CO: 4. Conference Internationale des Polychetes, Angers (France), 27 Jul-1 Aug 1992
SO: PROCEEDINGS-OF-THE-4TH-INTERNATIONAL-POLYCHAETE-CONFERENCE,-27-JULY-1-AUGUST-1992,-ANGERS,-FRANCE.-ACTES-DE-LA-4E-CONFERENCE-INTERNATIONALE-DES-POLYCHETES,-27-JUILLET-1-AOUT-1992,-ANGERS,-FRANCE. Dauvin,-J.-C.;Laubier,-L.;Reish,-D.J.-eds. PARIS-FRANCE EDITIONS-DU-MUSEUM-NATIONAL-D'-HISTOIRE-NATURELLE 1994 vol. 162 pp. 493-501
ST: MEM.-MUS.-NATL.-HIST.-NAT.-ZOOL. vol. 162
LA: English
ER: M (Marine)
AB: The influence of thc tube-building spionid Polydora ciliata Johnston on benthic community, sediment properties and exchange processes through the sediment surface was investigated. Findings showed that spionid tube lawns (eight or more tubes. cm- super(2)) lowered sediment stability and enhanced accumulation of suspended particles. Organic matter was selectively transported into the sediment via feeding, which enriched sediments by up to 100 %. Only a slight increase in fluid transport in the upper sediment layers was attributed to P. ciliata. Polydora tube lawns significantly increased abundance and diversity of meio- and macrofauna. Further they increased food input to the sediments and substrate area for colonization by micro- and meiofauna. Their fecal pellets may serve as a food source for meiofauna and chemotrophs in deeper sediment layers. Hence, Polydora ciliata, a well-known pioneer species, reconditions disturbed sediments, where it may represent a food item for benthic grazers.
AN: 3817307
209 of 1521
TI: Ecology and biogeochemistry of Paralvinella sulfincola at northeast Pacific hydrothermal vents: Review and comparison with Alvinella spp. of the East Pacific Rise
AU: Juniper,-S.K.
AF: Geotop & Dep. Sci. Biol., Univ. Quebec a Montreal, C.P. 8888, Succ.A., Montreal, PQ H3C 398, Canada
CO: 4. Conference Internationale des Polychetes, Angers (France), 27 Jul-1 Aug 1992
SO: PROCEEDINGS-OF-THE-4TH-INTERNATIONAL-POLYCHAETE-CONFERENCE,-27-JULY-1-AUGUST-1992,-ANGERS,-FRANCE.-ACTES-DE-LA-4E-CONFERENCE-INTERNATIONALE-DES-POLYCHETES,-27-JUILLET-1-AOUT-1992,-ANGERS,-FRANCE. Dauvin,-J.-C.;Laubier,-L.;Reish,-D.J.-eds. PARIS-FRANCE EDITIONS-DU-MUSEUM-NATIONAL-D'-HISTOIRE-NATURELLE 1994 vol. 162 pp. 453-462
ST: MEM.-MUS.-NATL.-HIST.-NAT.-ZOOL. vol. 162
LA: English
ER: M (Marine)
AB: The "sulfide worm" Paralvinella sulfincola Desbruyeres & Laubier 1993. of Northeast Pacific hydrothermal vents, builds mucous tubes on the surface of high temperature chimneys. as does Alvinella spp. on the East Pacific Rise. P. sulfincola is a deposit feeder and likely grazes on thermophilic chimney bacteria. It is argued that deposit feeding is also the primary source of nutrition for Alvinella spp. The influence of both worms on the sulfur cycle and on chimney mineralization processes is discussed. While Alvinella appears to be more elaborate in its adaptations to the high temperature chimney environment, the functional significance of some of these apparent adaptations remains unclear. Observed effects of P. sulfincola on chimney mineralization suggest that the question of how Alvinella spp. influences chimney growth patterns needs to be re-addressed. Two previously proposed roles for the epibiotic bacteria in Alvinella spp., nutrition and detoxification, can be accomplished by P. sulfincola without the aid of episymbionts. This is a strong argument for a re-evaluation of the nature of the Alvinella bacteria symbiosis.
AN: 3817302
210 of 1521
TI: Biogeochemical cycling of nutrients and trace metals in anoxic freshwater sediments of the Neckar River, Germany
AU: Song,-Y.; Muller,-G.
AF: Heidelberg Univ. Inst. of Sedimentol., D-69020 Heidelberg, FRG
CO: 6. International Symposium. International Association for Sediment Water Sciences Santa Barbara, CA (USA)
SO: MAR.-FRESHWAT.-RES. 1995 vol. 46, no. 1, pp. 237-243
NT: 33 ref.
LA: English
ER: F (Freshwater)
AB: Pore-water components including nutrients alkalinity and pH were determined at three sites in the Neckar River. Sequential extraction procedures and trace metals in both pore waters and sediments are reported in order to evaluate the mobility of trace metals in contaminated sediments. The results show that the mineralisation of organic matter plays an important role in the cycling. Pore-water profiles suggest that the element maxima at the sediment-water interface are caused by the decomposition of biomass. Low concentrations of dissolved trace metals in the anoxic sediments can be explained by a sharp decrease in sulphate in pore water concomitant with hydrogensulfide ion production. This leads to the formation of highly insoluble metal sulfides. Solubility calculations show that the sediments act as a sink for trace metals with respect to sulfides. No significant fluxes of ammonium or phosphate into overlying water were found, due to the existence of an oxic surface layer.
AN: 3815244
211 of 1521
TI: Comparison of the sedimentation of a diatom spring bloom and of a subsurface chlorophyll maximum
AU: Olesen,-M.
AF: Mar. Biol. Lab., Univ. Copenhagen, DK-3000 Helsingoer, Denmark
SO: MAR.-BIOL. 1995 vol. 121, no. 3, pp. 541-547
NT: Bibliogr.: 27 ref.
LA: English
ER: M (Marine)
AB: The seasonal pattern of sedimentation was determined over a 8-mo investigation period covering the productive season at a permanent station in the Southern Kattegat (Denmark) in 1990. The phytoplankton succession was characterised by a 4-mo long subsurface maximum associated with the pycnocline which was entirely dominated by the dinoflagellate Gyrodinium aureolum. The bulk sedimentation of organic matter took place during this period and accounted for >60% of the annual particulate organic carbon (POC) and particulate organic nitrogen (PON) sedimentation. The spring bloom period contributed 60% of the sedimentation of intact phytoplankton cells, but only 20% of the POC and PON sedimentation. A minor fraction of the sedimenting matter from the subsurface phytoplankton maximum consisted of intact phytoplankton (< 20%), suggesting that the phytoplankton was processed by heterotrophs and that it was mainly products from this activity which contributed to the vertical flux of organic matter. The variation in oxygen concentration below the pycnocline coincided with the pattern of sedimentation with a delay of 3 to 6 wk.
AN: 3812468
212 of 1521
TI: Evidence of the potential influence of planktonic community structure on the interannual variability of particulate organic carbon flux
AU: Boyd,-P.; Newton,-P.
AF: Dep. Oceanogr., Univ. British Columbia, 6270 University Blvd., Vancouver, BC V6T 1W5, Canada
SO: DEEP-SEA-RES.-I-OCEANOGR.-RES.-PAP. 1995 vol. 42, no. 5, pp. 619-639
LA: English
ER: M (Marine)
AB: The functioning of the biological pump during spring blooms was assessed with biogeochemical data from JGOFS (Joint Global Ocean Flux Study) process studies in the NE Atlantic during 1989 and 1990. A comparison of the integrated primary productivity signal (estimated by the super(14)C technique and from changes in ambient surface-water [tCO sub(2)] and [NO sub(3) super(-)] during the spring blooms of the two years revealed close similarities. These observations suggest that the magnitude of the biological drawdown of CO sub(2) via photosynthetic activity during these periods was comparable. However, despite similarities in the magnitudes of these and other surface rate processes, sediment trap particulate organic carbon (POC) fluxes at 3100 m representing the spring bloom settlement events were 1.8 times greater in 1989 than in 1990. Taking into account the spatial and temporal resolutions of pelagic and deep trap datasets, these observations suggest that the coupling between organic carbon production in surface waters and its transfer to the deep ocean was stronger in the period studied in 1989 than in 1990. That is, the biological pump was more efficient in 1989. The size of the dominant phytoplankton species was observed to the principal difference between the two spring bloom data sets. The potential influence of the observed algal size differences on the vertical POC flux was quantified from size-fractionated productivity data in conjunction with a food web-vertical flux model. The derived POC fluxes from the surface layer were two times greater in spring 1989 than in the bloom period in 1990, and a comparison of these flux estimates with those from other methods is favourable. Extrapolation of these derived shallow POC fluxes to 3100 m with existing empirical algorithms yields deep POC fluxes that are consistent with those collected by sediment traps at this depth. Differences in algal size between the two spring blooms can thus account for the observed interannual differences in deep-water POC fluxes without the need to invoke interannual differences in unmeasured mid-water processes. This work provides a clear demonstration that although observations of oceanic productivity may yield the input to the biological pump, they cannot, on annual timescales, reliably provide information on the efficiency of the pump in transferring carbon to the deep ocean.
AN: 3810599
213 of 1521
TI: The role of a silicate pump in driving new production
AU: Dugdale,-R.C.; Wilkerson,-F.P.; Minas,-H.J.
AF: Dep. Biol. Sci., Univ. Southern California, Los Angeles, CA 90089, USA
SO: DEEP-SEA-RES.-I-OCEANOGR.-RES.-PAP. 1995 vol. 42, no. 5, pp. 697-719
LA: English
ER: M (Marine)
AB: In the past, the importance of silicate as a limiting nutrient for new production in the ocean, and in determining global productivity and carbon budgets, has been relegated to the lower ranks compared to the role of nitrogen and, more recently, iron. This paper describes a "silicate pump" that acts in diatom-dominated communities to enhance the loss of silicate from the euphotic zone to deep water compared to nitrogen, which is more readily recycled in the grazing loop, thus leading the system to silicate limitation. The impact of this silicate pump is described for the HNLC (High Nutrient-Low Chlorophyll) waters offshore from 15 degree S, Peru and reproduced in a simulation model of a diatom-dominated ecosystem. Silicate pumping to deep water results in low silicate, high nitrate conditions in the mixed layer, shown here to be a characteristic of many HNLC areas. These areas should more accurately be termed HNLSLC (High Nitrate-Low Silicate-Low Chlorophyll) areas. Silicate dynamics may control and dominate new production processes in these areas and consequently control the rate at which newly upwelled CO sub(2) in the surface regions is reduced by the phytoplankton. In such silicate-controlled systems, export production (i.e. production that is lost to deep water) of silicon and nitrogen are not equivalent, since export production of silicon is controlled by input of silicate, whereas export production of nitrogen is controlled by grazing rate and regeneration.
AN: 3810597
214 of 1521
TI: Analytical intercomparison results from the 1990 Intergovernmental Oceanographic Commission open-ocean baseline survey for trace metals: Atlantic Ocean
AU: Landing,-W.M.; Cutter,-G.A.; Dalziel,-J.A.; Flegal,-A.R.; Powell,-R.T.; Schmidt,-D.; Shiller,-A.; Statham,-P.; Westerlund,-S.; Resing,-J.
AF: Dep. Oceanogr., Florida State Univ., Tallahassee, FL 32306-3048, USA
SO: MAR.-CHEM. 1995 vol. 49, no. 4, pp. 253-265
NT: Special Issue: IOC Contaminants Baseline Study.
LA: English
ER: M (Marine)
AB: "Dissolved" (<0.4 mu m filtered) and "total dissolvable" (unfiltered) trace element samples were collected using "clean" sampling techniques from four vertical profiles in the eastern Atlantic Ocean on the first IOC Trace Metals Baseline expedition. The analytical results obtained by 9 participating laboratories for Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, and Se on samples from station 4 in the northeast Atlantic have been evaluated with respect to accuracy and precision (intercomparability). The data variability among the reporting laboratories was expressed as 2 x SD for a given element and depth, and was comparable to the 95% confidence interval reported for the NASS seawater reference standards (representing analytical variability only). The discrepancies between reporting laboratories appear to be due to inaccuracies in standardization (analytical calibration), blank correction, and/or extraction efficiency corrections. Several of the sampling bottles used at this station were not adequately pre-cleaned (anomalous Pb results). The sample filtration process did not appear to have been a source of contamination for either dissolved or particulate trace elements. The trace metal profiles agree in general with previously reported profiles from the Atlantic Ocean. We conclude that the sampling and analytical methods we have employed for this effort, while still in need of improvement, are sufficient for obtaining accurate concentration data on most trace metals in the major water masses of the oceans, and to enable some evaluation of the biogeochemical cycling of the metals.
AN: 3810329
215 of 1521
TI: Behavior of dissolved antimony, arsenic, and selenium in the Atlantic Ocean
AU: Cutter,-G.A.; Cutter,-L.S.
AF: Dep. Oceanogr., Old Dominion Univ., Norfolk, VA 23529-0276, USA
SO: MAR.-CHEM. 1995 vol. 49, no. 4, pp. 295-306
NT: Special Issue: IOC Contaminants Baseline Study.
LA: English
ER: M (Marine)
AB: Vertical profiles for dissolved antimony, arsenic, and selenium were obtained at four stations in the eastern basins of the North and South Atlantic Ocean, and on a surface-water transect from 24 degree S to 31 degree N. Total dissolved selenium displays surface-water depletion and deep-water enrichment, with organic selenide (selenium in soluble peptides) being the predominant species in surface waters and selenate predominating in deep waters. Although the concentrations of total selenium in surface waters of the Northern and Southern Hemispheres are similar, the ratio of inorganic to organic selenium is strongly influenced by the intensity of upwelling. Total inorganic arsenic is depleted in the surface waters of all stations, and increases to relatively constant deep-water concentrations (c. 20 nmol/l). In contrast, total inorganic antimony shows surface-water maxima at two stations. Although the average surface-water arsenic and antimony concentrations in the Northern and Southern Hemispheres are identical, there is some evidence for the atmospheric deposition of antimony. Overall, the cycling of the metalloids in the Atlantic is dominated by in situ biotic reactions, and modified by inputs from upwelling and atmospheric deposition.
AN: 3810326
216 of 1521
TI: Reactive mercury in the eastern North Atlantic and southeast Atlantic
AU: Dalziel,-J.A.
AF: Phys. and Chem. Sci. Branch, Dep. Fish. and Oceans, Bedford Inst. Oceanogr., P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada
SO: MAR.-CHEM. 1995 vol. 49, no. 4, pp. 307-314
NT: Special Issue: IOC Contaminants Baseline Study.
LA: English
ER: M (Marine)
AB: The vertical distribution of reactive mercury has been measured at two stations in the eastern North Atlantic and one station in the southeast Atlantic in conjunction with the IOC Open Ocean Baseline Survey. The average concentrations of reactive Hg in vertical profiles ranged from 0.70 to 1.07 pM with the highest values found at the northeast Atlantic stations and the lowest at the southeast station. No significant concentration gradients were found below the surface mixed layer at the two stations in the eastern North Atlantic. At station 7, in the southeast Atlantic, an increase in reactive Hg was noted in the water adjacent to the mixed layer (35-200 m) which was coincident with an oxygen depletion, down to 20% saturation at 200 m. The concentration of reactive Hg in the North Atlantic Deep Water (0.48-1.34 pM), the Antarctic Intermediate Water (0.47 pM), the Antarctic Bottom Water (0.67-1.25 pM), and the Mediterranean Outflow Water (0.83-1.06 pM) were noted. The trends in Hg concentration in the water masses between stations showed the concentration decreasing with distance from the water mass source except for Hg in the Antarctic Bottom Water. The increase noted in this water mass was attributed to mixing with North Atlantic Deep Water and or release from bottom sediments.
AN: 3810325
217 of 1521
TI: Mineralization of inositol hexaphosphate in aerobic and anaerobic marine sediments: Implications for the phosphorus cycle
AU: Suzumura,-M.; Kamatani,-A.
AF: Lab. Mar. Biochem., Ocean Res. Inst., Univ. Tokyo, Minamidai, Nakano-ku, Tokyo 164, Japan
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 5, pp. 1021-1026
LA: English
ER: M (Marine)
AB: Inositol hexaphosphate (IP sub(6)) is a significant carrier of organic P in riverine sediments and suspended matter. Its mineralization in coastal sediments was investigated by laboratory experiments under simulated marine environments. Despite being chemically refractory, IP sub(6) was effectively mineralized to inorganic P by aerobic and anaerobic degradation processes. The extent and rate of IP sub(6) mineralization were found to be strongly regulated by the redox conditions: under anaerobic conditions, IP sub(6) decomposed almost completely within 40 days, whereas about 50% of IP sub(6) remained under aerobic conditions during a 60 days experiment. Most of the IP sub(6) added to sediment/seawater mixtures was bound to the sediment particles in both aerobic and anaerobic samples. The soluble fraction of IP sub(6) in the aqueous phase was, however, depressed under aerobic conditions, which could account for the reduced efficiency of aerobic IP sub(6) mineralization. These results suggest that terrigenous IP sub(6) decomposes rapidly under marine environmental conditions and thus may be an important P source in marine ecosystems.
AN: 3810312
218 of 1521
TI: First data on trace metal level and behaviour in two major Arctic river-estuarine systems (Ob and Yenisey) and in the adjacent Kara Sea, Russia
AU: Dai,-M.-H.; Martin,-J.-M.
AF: Inst. Biogeoch. Mar., UA CNRS No. 386, Unit. Rech. Mar. IFREMER No. 6, Ecole Norm. Super., 1 Rue Maurice Arnoux, 92120 Montrouge, France
SO: EARTH-PLANET.-SCI.-LETT. 1995 vol. 131, no. 3-4, pp. 127-141
LA: English
ER: B (Brackish)
AB: Dissolved and colloidal trace element concentrations (Cd, Cu, Fe, Ni, and Pb) were determined in the Ob and Yenisey river-estuary systems and in the adjacent Kara Sea in September 1993. The data show a natural low concentration level of 'dissolved' (<0.4 mu m) trace metals (Cd, Cu, Fe, Ni, and Pb) in the two rivers and in the Kara Sea as compared to world unpolluted rivers and the central Arctic Ocean, suggesting that the region studied is pristine with respect to trace metals. The pathway of trace metals transported from rivers to the ocean seems to be complicated, and largely influenced by biogeochemical processes taking place in the estuarine mixing zone. Colloidal material (10 super(4) Daltons-0.4 mu m), in addition to its significant contribution to the so-called 'dissolved' fraction, has been shown to play a fundamental role in determining the behaviour of both conservative and non-conservative trace metals during estuarine mixing. Hence, colloids may control to a large extent the fate of 'dissolved' trace metals as well as their net input from the rivers to the Kara Sea.
AN: 3810310
219 of 1521
TI: In-situ measurement of dissolved nitrogen and oxygen in the ocean
AU: McNeil,-C.L.; Johnson,-B.D.; Farmer,-D.M.
AF: Inst. Ocean Sci., 9860 W. Saanich Rd., P.O. Box 6000, Sidney, BC, Canada
SO: DEEP-SEA-RES.-I-OCEANOGR.-RES.-PAP. 1995 vol. 42, no. 5, pp. 819-826
LA: English
ER: M (Marine)
AB: Motivated by the need to separate changes in dissolved gas concentrations due to air-sea fluxes from biological production, a novel method of inferring dissolved nitrogen in the ocean is described. The method requires a local measurement of gas tension, dissolved oxygen, water temperature and salinity. Such instrumentation has been developed and tested at sea. Preliminary open ocean data are presented. The measurements during periods of low wind speed show a clear diurnal dissolved oxygen signal, incorporating biological photosynthetic response, solar heating and nocturnal convective mixing. The diurnal variability of the inferred nitrogen signal is approximately 10% that of the measured oxygen diurnal variability. The nitrogen diurnal variability is attributed to a 10 m separation between the primary measurements of gas tension and dissolved oxygen rather than any intrinsic change in dissolved nitrogen. These results are, however, consistent with the relative insensitivity of dissolved gaseous nitrogen to biological activity compared to that of dissolved oxygen. The open ocean results give good evidence for the integrity of the measurement scheme and indicate the potential for simultaneous measurement of dissolved nitrogen and oxygen in the study of biological cycling as well as gas transfer in the upper ocean.
AN: 3810251
220 of 1521
TI: Experimental transplantation of eelgrass (Zostera marina) in Kiel Bight, Baltic Sea: Effects of sediment nutrient enrichment and initial shoot density
AU: Worm,-B.; Reusch,-T.B.H.
AF: Inst. Meeresk., 24105 Kiel, FRG
CO: 23. Benthic Ecology Meeting, New Brunswick, NJ (USA), 17-19 Mar 1995
SO: TWENTY-THIRD-BENTHIC-ECOLOGY-MEETING. Grassle,-J.P.;Kelsey,-A.;Oates,-E.;Snelgrove,-P.V.-eds. Rutgers-the-State-Univ.,-New-Brunswick,-NJ-USA.-Inst.-Marine-Coastal-Sciences 1995 vp
NT: Abstract only.
LA: English
ER: M (Marine)
AB: Although considerable loss of eelgrass habitats has occurred in the Baltic Sea during the past decades mitigation measures by transplantation have not yet been attempted. The goal of this experiment was to investigate effects of fertilization (with additional transplantation of Mytilus edulis or with a commercial slow-release NPK-fertilizer) and planting density (20 or 40 cm distance between shoots) on plant performance, shoot density and areal extension of transplants. In contrast to previous techniques involving shootbundles, we planted only single shoots which were equidistantly placed in circular plots. In situ leaf growth rates in July were significantly higher when Zostera was associated with Mytilus whereas application of the commercial fertilizer had no effect on any of the response variables. Surprisingly, the increase in shoot density over a 6.5 month period in the high-density plots was double the increase found in the low-density plots. Also, with higher transplant density, we found relatively higher rates for shoot growth, shoot addition and transplant coverage, suggesting the presence of mutualistic processes among eelgrass shoots.
AN: 3809917
221 of 1521
TI: Amount of water, energy and heating brought by Estonian rivers to the Baltic Sea
AU: Vedom,-R.
AF: Estonian Meteorol. Hydrol. Inst., Liivalaia 9, EEO1O6 Tallinn, Estonia
CO: First Study Conference on BALTEX, Visby (Sweden), 28 Aug-1 Sep 1993
SO: FIRST-STUDY-CONF.-ON-BALTEX. A.-Omstedt-ed. GEESTHACHT-GERMANY INT.-BALTEX-SECRETARIAT 1995 vol. 3 pp. 176-177
ST: vol. 3,
NT: Summary only.
LA: English
ER: M (Marine)
AB: The purpose of this paper is to create the approximate carrying-out model for water, energy and heating as a basis for future estimates of suspended matter, hydrochemical and/or biological components of input to the Baltic Sea from Estonia.
AN: 3809213
222 of 1521
TI: Oxygen and carbon isotope study of the Holocene oyster reefs and paleoenvironmental reconstruction on the northwest coast of Bohai Bay, China
AU: Hong,-Wang; Keppens,-E.; Nielsen,-P.; Van-Riet,-A.
AF: Dep. Quaternary Geol., Tianjin Inst. Geol. and Mineral Resour., MGMR, Tianjin 300170, People's Rep. China
SO: MAR.-GEOL. 1995 vol. 124, no. 1-4, pp. 289-302
NT: Special Issue: Coastal Evolution in the quaternary: IGCP Project 274.
LA: English
ER: M (Marine)
AB: The northwest coast of Bohai Bay supports large areas of Holocene Crassostrea gigas (oyster) reefs. Their huge size and the fact that the shells are composed of consecutive microgrowth layers, consisting of primary calcite, make them an ideal object for a stable isotope study. The delta super(18)O and delta super(13)C compositions of the oysters reveal a number of interesting features. The most important are annual cycles related to seasonal variations, the regional delta super(18)O (water) versus salinity ratio, and a stop in shell secretion below a water temperature of 11.5 plus or minus 1.5 degree C. Between ca. 6500 yrs cal B.P. and 2300 yrs cal B.P. the salinity in Bohai Bay increased from less than 20ppt to 30ppt. Based on geological data combined with ecological data from C. gigas, we suggest that precipitation decreased during this period, while the input of fluvial sediments increased. The sediment load of rivers increased markedly after ca. 4000 yrs cal B.P., possibly due to a change in climate. In our study area this resulted in the development of the Oyster Plain.
AN: 3809165
223 of 1521
TI: A U.S. JGOFS process study in the equatorial Pacific (EqPac): Introduction
AU: Murray,-J.W.; Johnson,-E.; Garside,-C.
AF: Sch. Oceanogr., Univ. Washington, P.O. Box 35794, Seattle, WA 98195-7940, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1995 vol. 42, no. 2-3, pp. 275-293
LA: English
ER: M (Marine)
AB: This special issue contains data and scientific results from the JGOFS Process Study in the equatorial Pacific. Most of the contributions are from the U.S. JGOFS Process Study (EqPac) but the French and Australian results are represented as well. The equatorial Pacific plays a major role in the oceanic and atmospheric carbon cycles, and these studies are the first step for synthesizing the cycle of carbon and related elements in this region.
AN: 3808484
224 of 1521
TI: The effects of vegetation on watershed biogeochemistry at Loch Vale Watershed, Rocky Mountain National Park, Colorado
AU: Arthur,-M.A.
CA: Cornell University
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1990 vol. 51, no. 4, 196 pp
NT: Diss. Ph.D.: Order No.: DA9027102.
LA: English
ER: F (Freshwater)
AB: I examined the biogeochemistry of Loch Vale Watershed (LVWS) in Rocky Mountain National Park because scientists and policy-makers are concerned about the lack of information regarding the possible susceptibility of Rocky Mountain watersheds to damage from acid deposition. The objective of the research was to quantify the role of the forest vegetation, which comprised about 6% of the watershed area, in controlling watershed biogeochemistry. Specifically, I estimated the magnitude of acid generation within the ecosystem and compared this with acid deposition to better understand ecosystem biogeochemistry. Knowledge about the intensity of internally-generated acidity will improve our ability to predict future impacts of acidic atmospheric deposition on the watershed and its biota. To calculate the generation of acidity within the forest it was necessary to quantify the major fluxes of basic cations and acid anions, including canopy and soil leaching, tree root uptake and return in litter fall, and mineralization of detritus. A series of process studies was performed in intensive research plots within LVWS to quantify these fluxes. The process studies revealed that the old-growth forest in LVWS was maintained by active recycling of nutrients. For example, large amounts of K, Ca, and dissolved organic carbon were leached from the forest canopy by summer rains, whereas NH sub(4) and NO sub(3) were retained by the canopy. Net primary production (NPP) in the LVWS was relatively low (441 g/m super(2)/yr), but root uptake of basic cations, which replaced nutrients in senesced tissues, was high (210 mEq/m super(2)/yr). A large proportion of NPP and root uptake was associated with fine root production and turnover (34 percent). Organic anions and SO sub(4) were the principal mobile anions in soil solutions, due to coarse soils and very low sulfate adsorption capacity. Flux of free acidity from the soil was very low (4.5 mEq/m super(2)/yr); thus, H-ions released to the soil during root uptake were completely consumed within the soil by ion exchange reactions and primary mineral weathering. Weathering rates in the forest were about four times higher than in non-forested areas of the watershed. Both the release of acidity during root uptake and the dissociation of large quantities of weak acid organic anions in the soil contributed substantially to the higher rate of weathering. On a forest area basis, the accumulation of cations in biomass accounted for 10 times as much H-ion generation as did precipitation inputs. On a whole watershed basis, forest growth generated about 2/3 as much acidity as was added by atmospheric deposition. Forests play an important role in the acid-base balance of subalpine ecosystems; thus, any disturbance to the forested area could have a disproportionate impact on watershed biogeochemistry. (DBO)
AN: 3808376
225 of 1521
TI: Ecosystem analysis of the Bering/Chukchi seas using a coupled time-dependent physical/biological simulation model
AU: Shuert,-P.G.
CA: University of South Florida
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1990 vol. 51, no. 4, 205 pp
NT: Diss. Ph.D.: Order No.: DA9024916.
LA: English
AB: A coupled, time-dependant, 3-dimensional, physical/biological mathematical model was constructed to simulate some of the important biological and physical processes of the northern Bering and southern Chukchi Sea ecosystem. This model simulates the time-dependant changes in nutrient and chlorophyll fields on a broad ecosystem scale to examine the importance of physical forcing and chemical conditions on biological rates, particularly primary production. Some of the important results from the model follow. The distribution of chlorophyll and productivity in the northern Bering Sea is determined primarily by the strength of the advection and secondarily by the nutrient and chlorophyll distributions at the southern boundaries of the model domain. Ammonium concentrations are spatially determined by both benthic regeneration and by the advective field. Approximately 60% of the nitrate entering the model remains unutilized, to be exported at the model's downstream boundary within similar to 200 Km of the Siberian coast. This unutilized nitrate presumably is available to enrich the nutrient concentrations of the East Siberian Sea waters at least as far west as Wrangel Island. Declining light availability from mid-summer on, manifested in shorter daylengths and lower sun angles, leads to a decline in productivity in spite of ample nutrients. Zooplankton are an unimportant influence on chlorophyll, productivity and nutrient distributions, consuming only similar to 1% of the daily productivity. Benthic respiration of carbon, and concomitant regeneration of nitrogen, constitute important sources of dissolved carbon and nitrogen to the model domain, without which, productivity is significantly curtailed. Approximately 3.6 g C/m super(2)/yr (calculated over 150 days), is buried in the Bering/Chukchi Sea sediments, or similar to 1% of the annual productivity. (DBO)
AN: 3808370
226 of 1521
TI: Studies of trace metals in shelf waters of the British Isles
AU: Tappin,-A.D.
CA: University of Southampton (United Kingdom)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1990 vol. 51, no. 4, 332 pp
NT: Diss. Ph.D.: Order No.: BRDX89593.
LA: English
AB: Results are presented for the distributions of a number of dissolved trace metals (Cd, Co, Cu, Mn, Ni, Pb, Sn; ancillary data were also available for reactive aluminium) during several detailed surveys of the central and western areas of the English Channel. The sampling plan was designed to give information on the importance of potential sources of metals in influencing distributions, and sampling was undertaken under contrasting seasonal conditions (Nov. 1985, May & Aug. 1986) in order to obtain information on the effects of phytoplankton activity and water column stability on the biogeochemical cycling of metals. The mixing of Atlantic Ocean surface water and freshwaters with higher concentrations of dissolved trace metals was a significant basic factor affecting the distributions of the trace metals, as shown by significant inverse correlations of each metal investigated, with salinity. The scatter shown in these relationships indicates, however, that other factors influenced the distributions, and the possible roles of atmospheric and benthic inputs, and of interactions between dissolved and particulate (including biogenic) material are considered. Concentrations of dissolved manganese increased progressively from winter to summer (2.0 plus or minus 0.7 (mean plus or minus .0) to 5.0 plus or minus 3.0 nmol/l). A surface enrichment in the upper mixed layer of the western Channel, relative to deeper water, was also observed. Concentrations of dissolved cobalt also increased from winter to spring (from less than or equal to 0.02-0.50 to 0.08-0.71 nmol/l), paralleling those of dissolved manganese, and then decreased into summer (to less than or equal to 0.08-0.56 nmol/l). The regional distribution of dissolved lead had changed by May, possibly reflecting removal by diatoms and decreased riverine inputs, although overall mean concentrations remained similar throughout the year (0.22 nmol/l). Concentrations of reactive aluminium decreased in response to biological activity, being related to those of dissolved silicon during spring, and to those of phosphate and nitrate during the summer, with depletion in the upper mixed layer of the stratified waters of the western Channel. Concentrations of dissolved cadmium (0.20 nmol/l), copper (3.2 nmol/l), nickel (3.8 nmol/l) and zinc (7.6 nmol/l), and their regional distributions, remained relatively uniform over the period of the cruises. This behaviour, which contrasts with the open oceanic observations (surface depletion and regeneration at depth), may be attributable to high background levels of dissolved metals, rapid recycling of metals from sedimented phytoplankton, increased riverine inputs, and rapid mixing of the water column, which prevents the integrated effects of repeated cycles of removal from the euphotic zone from developing. (DBO)
AN: 3808181
227 of 1521
TI: Biogeochemical phosphorus cycling in the Delaware, an urbanized coastal plain estuary
AU: Lebo,-M.E.
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1991 vol. 51, no. 11, 272 pp
NT: Diss. Ph.D.: Order No.: DA9109948.
LA: English
ER: B (Brackish)
AB: Man's activities over the past several centuries have greatly affected the transport and cycling of phosphorus in estuaries. In the Delaware Estuary, industrial and municipal inputs into the tidal river near Philadelphia strongly influence both nutrient cycles and water chemistry. In the tidal river, the flux of phosphorus increases by 280% due to large inputs. The observed increase is, however, much lower than expected from known inputs to the system. Within the tidal river, geochemical processes remove 50-65% of phosphorus inputs; large increases occur in particulate phosphorus associated with iron, aluminum, and organic matter. This geochemical repackaging within the river partially mitigates the impact of anthropogenic phosphorus inputs, and it leads to a nearly constant flux of phosphorus into the salinity gradient. In addition to increasing phosphorus transport, anthropogenic inputs also change the ecology of phosphorus cycling. In the region of maximum anthropogenic inputs, bacteria rather than phytoplankton dominated (up to 70%) the uptake of phosphate. Throughout the remainder of the estuary, phytoplankton contributed 75-85% of biological phosphate uptake. In contrast to the urban river, phosphorus cycling in Delaware Bay (salinity gradient) is dominated by biological production. Although phosphorus is released from both suspended and bottom sediments, phosphate uptake and regeneration within the water column control phosphate concentrations. The link between phosphorus cycling in the bay and biological production imparts strong seasonal variations in phosphorus distributions. During the intense spring phytoplankton bloom, phosphate is completely removed, and 50% of total phosphorus entering from the river is retained within the bay. This trapping of phosphorus is only temporary, however, as phosphorus is regenerated after the bloom dissipates in the late spring. On an annual basis, 87% of the phosphorus entering the bay from the river is exported to coastal waters. (DBO)
AN: 3808115
228 of 1521
TI: Geochemical and physical processes influencing the composition of particles in diverse environments, eastern North Atlantic Ocean
AU: Isley,-A.E.
CA: University of Rhode Island
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1991 vol. 51, no. 11, 173 pp
NT: Diss. Ph.D.: Order No.: DA9109466.
LA: English
ER: M (Marine)
AB: To understand global biogeochemical cycling in the oceans it is imperative to develop comprehensive models of the processes influencing elements in the suspended particulate phase. This thesis examines the character of particles from a wide variety of environments in the Eastern North Atlantic Ocean in order: (1) to enhance our knowledge of the physical and geochemical processes influencing resuspended matter; (2) to determine over what distances distinct water masses can transport characteristic particle suites; (3) to develop models for the formation and transformation of distinct mineral phases associated with hydrothermal plumes. Particles were collected by filtering water from 30 liter Niskin bottles and by using in situ high-volume filtration equipment during the FLUX-ATLANTE (R/V Suroit, 1985) and RRS Discovery 159 (1986) cruises. Particles were characterized using some or all of the following techniques: instrumental neutron activation (for Al, Ca, Fe, Mn, Cu, V, and/or I), scanning electron microscopy and energy dispersive x-ray analyses. Differences between resuspended nepheloid materials and underlying surface sediments are attributed to preferential resuspension of fine-grained materials with a distinctive geochemical signature. Classical signs of early alteration processes such as dissolution of biogenic tests and remineralization of organic matter in the sediment column are observed. Long-distance transport (to 800 km) of aluminosilicates occurs with advection of Mediterranean Outflow Water (MEDW). Mixing with Eastern North Atlantic Intermediate Water (ENAIW) accounts for an enhanced particulate Ca/Al and Mn/Al in intermediate waters with distance from Gibraltar and there is no evidence for adsorption of dissolved Mn introduced with the MEDW plume over distance scales approximately 1000 km. Between 15 to 75% of the materials transported in the Trans-Atlantic Geotraverse hydrothermal plume (26 degree N, Mid-Atlantic Ridge) are of resuspended origin. Hydrothermal particles are dominated by amorphous iron oxides along the length of the equilibrated plume. Copper oxides are present in the region of 2.5 km from the venting site. Manganese-rich particles are introduced to the plume via resuspension. Sulfides may be transported into the far-field hydrothermal plume only if their grain sizes are <3 mu . (DBO)
AN: 3808114
229 of 1521
TI: Secondary suspended particulate matters and the bioelement loop in sea water column
AU: Wu,-Yuduan; Chen,-Cimei; Luo,-Xiaohong
AF: Dep. Oceanogr., Xiamen Univ., Xiamen 361005, People's Rep. China
SO: TROP.-OCEANOL.-REDAI-HAIYANG 1994 vol. 13, no. 3, pp. 84-89
LA: Chinese
ER: M (Marine)
AB: We studied the process of marine environment resources development (mainly the resources of productivity and purification ability) in the coastal area, in which the formation of the secondary suspended particulate matters is induced, especially the aquatic culture rises and domestic sewage discharges in the nearshore zone. The following topics were emphasized: The mechanisms of the secondary S.P.M. formed; The buffering and controlling role in geochemical behaviour, process, fate and cycle of bioelement in water column; The effect on the kinetics of transformation among the various speciations of bioelement and the content levels of nutrient in water. Therefore, it may turn into a potential source for the eutrophication in near shore water.
AN: 3802993
230 of 1521
TI: Dissolved organic carbon in the equatorial Atlantic Ocean
AU: Thomas,-C.; Cauwet,-G.; Minster,-J.-F.
AF: UMR39/GRGS, 18 Ave. E. Belin, 31055 Toulouse, France
SO: MAR.-CHEM. 1995 vol. 49, no. 2-3, pp. 155-169
LA: English
ER: M (Marine)
AB: We measured the concentration of dissolved organic carbon (DOC) in the equatorial Atlantic Ocean, using a high-temperature carbon oxidation technique and platinized-quartz catalysts. Below 400 m, values are nearly homogeneous near 46 plus or minus 7 mu M C. Concentrations are higher, up to 97 mu M C at the surface, outside of the equatorial upwelling during the warm season. They are somewhat lower, near 66 mu M C on average, in upwelling waters during the cold season. These values are close to previously published data from the subtropical Atlantic Ocean, and to recent values for the Pacific Ocean. A box model of the equatorial upwelling suggests that only 20 plus or minus 15% of the exported flux of total biogenic carbon is in dissolved form.
AN: 3802697
231 of 1521
TI: Sedimentary organic matter preservation: An assessment and speculative synthesis
AU: Hedges,-J.I.; Keil,-R.G.
AF: Sch. Oceanogr., Box 357940, Univ. Washington, Seattle, WA 98195-7940, USA
SO: MAR.-CHEM. 1995 vol. 49, no. 2-3, pp. 81-115
LA: English
ER: M (Marine)
AB: Throughout Earth history, almost all preserved organic matter has been incorporated in marine sediments deposited under oxygenated waters along continental margins. Given modern oceanic productivity and sediment burial rates of 50 x 10 super(15) and 0.16 x 10 super(15) gC yr super(-1), respectively, organic preservation in the marine environment is <0.5% efficient. Although correlative information is often used to suggest that productivity, sediment accumulation rate, bottom water oxicity, and organic matter source are key variables, the mechanisms governing sedimentary organic matter preservation have remained unclear. The factors which directly determine preservation vary with depositional regime, but have in common a critical interaction between organic and inorganic materials over locally variable time scales. More than 90% of total sedimentary organic matter from a wide variety of marine depositional environments cannot be physically separated from its mineral matrix. This strongly associated organic component varies directly in concentration with sediment surface area and thus appears to be sorbed to mineral grains. Sediments accumulating outside deltas along continental shelves and upper slopes characteristically exhibit mineral surface area loadings approximately equivalent to a single molecular covering. These monolayer-equivalent coatings include a fraction of reversibly bound organic molecules that are intrinsically labile, but resist appreciable mineralization as they pass rapidly through oxygenated surface sediments and are preserved within underlying anoxic deposits. The delivery of mineral surface area is the primary control on organic matter preservation within these expansive coastal margin regions where roughly 45% of all organic carbon accumulates. Deltaic sediments account for roughly another 45% of global carbon burial, but often exhibit much less than monolayer-equivalent organic coatings. This pattern is seen in periodically oxygenated sediments off the mouth of the Amazon River, even though the component clastic minerals are discharged by the river with monolayer coatings. Comparably extensive losses of organic matter, including distinct particles such as pollen grains, occur in the surfaces of deep-sea turbidities in which long term reaction with O sub(2) is clearly the causative factor. Sub-monolayer organic coatings also are observed in continental rise and abyssal plain sediments where slower accumulation rates and deeper O sub(2) penetration depths result in increased oxygen exposure times and little ( similar to 5% of the global total) organic matter preservation. A transition zone between monolayer and sub-monolayer organic coatings apparently occurs on lower continental slopes, and is marked along the Washington coast by parallel offshore decreases in total organic matter and pollen between 2000-3000 m water depth.
AN: 3802689
232 of 1521
TI: Sedimentary organic matter preservation: An assessment and speculative synthesis -- a comment
AU: Pedersen,-T.F.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada
SO: MAR.-CHEM. 1995 vol. 49, no. 2-3, pp. 117-119
LA: English
ER: M (Marine)
AN: 3802688
233 of 1521
TI: Sedimentary organic matter preservation: An assessment and speculative synthesis -- a comment
AU: Berner,-R.A.
AF: Dep. Geol. and Geophys., Yale Univ., New Haven, CT 06520-8109, USA
SO: MAR.-CHEM. 1995 vol. 49, no. 2-3, pp. 121-122
LA: English
ER: M (Marine)
AN: 3802687
234 of 1521
TI: Sedimentary organic matter preservation: An assessment and speculative synthesis -- a comment
AU: Mayer,-L.M.
AF: Dep. Oceanogr., Darling Mar. Cent., Univ. Maine, Walpole, ME 04573, USA
SO: MAR.-CHEM. 1995 vol. 49, no. 2-3, pp. 123-126
LA: English
ER: M (Marine)
AN: 3802686
235 of 1521
TI: Sedimentary organic matter preservation: An assessment and speculative synthesis -- a comment
AU: Henrichs,-S.M.
AF: Inst. Mar. Sci., P.O. Box 757220, Univ. Alaska, Fairbanks, AK 99775-7220, USA
SO: MAR.-CHEM. 1995 vol. 49, no. 2-3, pp. 127-136
LA: English
ER: M (Marine)
AN: 3802685
236 of 1521
TI: Sedimentary organic matter preservation: An assessment and speculative synthesis
AU: Hedges,-J.I.; Keil,-R.G.
SO: MAR.-CHEM. 1995 vol. 49, no. 2-3, pp. 137-139
LA: English
ER: M (Marine)
AN: 3802684
237 of 1521
TI: Oceanic transport and storage of carbon emissions
AU: Keller,-A.A.; Goldstein,-R.A.
AF: Electric Power Res. Inst., P.O. Box 10412, Palo Alto, CA 94303, USA
SO: CLIM.-CHANGE 1995 vol. 30, no. 4, pp. 367-395
LA: English
ER: M (Marine)
AB: Using a global carbon cycle model (GLOCO) that considers seven terrestrial biomes, surface and deep ocean layers based on the HILDA model and a single mixed atmosphere, we analyzed the response of atmospheric CO sub(2) concentration and oceanic DIC and DOC depth profiles to additions of carbon to the atmosphere and ocean. The rate of transport of carbon to the deepest oceanic layers is rather insensitive to the atmosphereic-ocean surface gas exchange coefficient over a wide range, hence discrepancies between researchers on the precise global average value of this coefficient do not significantly affect predictions of atmospheric response to anthropogenic inputs. Upwelling velocity, on the other hand, amplifies oceanic response by increasing primary production in the upper ocean layers, resulting in a larger flux into DOC and sediments and increased carbon storage; experiments to reduce the uncertainty in this parameter would be valuable. The location of the carbon addition, whether it is released in the atmosphere or in the middle of the oceanic thermocline, has a significant impact on the maximum atmospheric CO sub(2) concentration (pCO sub(2)) subsequently reached, suggesting that oceanic burial of a significant fraction of carbon emissions (e.g. via clathrate hydrides) may be an important management option for limiting pCO sub(2) buildup. Our analysis indicates that the effectiveness of ocean burial decreases asymptotically below about 1000 m depth. With a constant emissions scenario (at 1990 levels), pCO sub(2) at year 2100 is reduced from 501 ppmv considering all emissions go to the atmosphere, to 422 ppmv with ocean burial at a depth of 1000 m of 50% of the fossil fuel emissions. An alternative scenario looks at stabilizing pCO sub(2) at 450 ppmv; with no ocean burial of fossil fuel emissions, the rate of emissions has to be cut drastically after the year 2010, whereas oceanic burial of 2 GtC/yr allows for a smoother transition to alternative energy sources.
AN: 3802655
238 of 1521
TI: A comparison of electron transport system (ETS) activity in stream and beaver pond sediments
AU: Songster-Alpin,-M.S.; Klots,-R.L.*
AF: Dep. Biol. Sci., SUNY, Cortland, NY 13045, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI.-J.-CAN.-SCI.-HALIEUT.-AQUAT. 1995 vol. 52, no. 6, pp. 1318-1326
LA: English
ER: F (Freshwater)
AB: Electron transport system (ETS) activity of sediments as an indication of microbial metabolic activity was measured at four beaver pond sites in central New York State. ETS activity, an indication of microbial biomass and respiration, was measured as the reduction of 2-(p-iodophenyl) -3- (p-nitrophenyl) -5- phenyl tetrazolium chloride (INT) to INT-formazan. Since INT can be reduced by both aerobes and anaerobes, the total microbial respiratory activity in the sediments was measured. The ETS activity increased from means of 11.1-65.0 mu g O sub(2) g super(-1) dry weight h super(-1) at the free-flowing upstream reaches to means of 221.2-262.6 mu g O sub(2) g super(-1) dry weight h super(-1) within the beaver ponds. ETS activity decreased with increased depth of sediment probably because of the loss of aerobic activity.
AN: 3802561
239 of 1521
TI: The chemistry of the anoxic waters in the Framvaren Fjord, Norway
AU: Yao,-Wensheng; Millero,-F.J.
AF: Univ. Miami, Rosenstiel Sch. Mar. Atmos. Sci., 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: AQUAT.-GEOCHEM. 1995 vol. 1, no. 1, pp. 53-88
LA: English
ER: B (Brackish)
AB: In the summer of 1993, a number of chemical parameters (H sub(2)S, O sub(2), pH, TA, TCO sub(2), NH sub(4) super(+), PO sub(4) super(3-), Mn super(2+) and Fe super(2+)) were measured in the Framvaren Fjord, a permanently super-anoxic fjord in southern Norway. The extremely steep gradient of sulfide near the interface suggests that other than downward flux of oxygen, three other possible oxidants, particulate manganese and iron oxides, phototrophic sulfur oxidation bacteria and horizontally transported oxygen account for the oxidation of the upward flux of H sub(2)S. Water intrusion through the sill accounts for the temperature inflection above the interface, which, together with internal waves (Stigerbrandt and Molvaer, 1988), may cause fluctuations of the depth of interface. Significant gradients of hydrographic properties and chemical species between 80-100 m suggest that there is a "second interface" at about 90 m that separates the deep and older bottom waters. A stoichiometric model is applied to examine the biogeochemical cycles of S, C, N and P in the Framvaren. High C:S, C:N and C:P ratios are found while the nutrients (N, P) have Redfield ratio. Based on the C:N:P ratio of 155:16:1 in organic matter, about 30% of sulfide produced by sulfate reduction is estimated to be removed by processes such as oxidation, formation of FeS sub(2), degassing and incorporation into organic matter. The rates of oxidation of H sub(2)S by Mn and Fe oxides in the water near the interface were slightly faster than the observed values in the laboratory, probably due to the presence of bacteria.
AN: 3800555
240 of 1521
TI: Prospects for modeling the behavior and fate of mercury, globally and in aquatic systems
AU: Mackay,-D.; Wania,-F.; Schroeder,-W.H.
AF: Inst. Environ. Stud., Univ. Toronto, Toronto, ON M5S 1A4, Canada
CO: 3. International Conference on Mercury as a Global Pollutant, Whistler, BC (Canada), 10-14 Jul 1994
SO: THIRD-INTERNATIONAL-CONFERENCE-ON-MERCURY-AS-A-GLOBAL-POLLUTANT. Porcella,-D.;Huckabee,-J.;Wheatley,-B.-eds. 1995 vol. 80, no. 1-4 pp. 941-950
ST: WATER,-AIR,-SOIL-POLLUT. vol. 80, no. 1-4
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The phenomena of cold condensation and fractionation of chemical contaminants on a global scale are discussed. The net result of these phenomena is that concentrations of certain atmospherically transported contaminants are higher than expected in the condensed, i.e. non gaseous media of water, soils, sediments and biota as a result of the temperature dependence of partitioning and transport phenomena. It is argued that the phenomena are best investigated by a combination of monitoring and modeling. This approach is illustrated in the form of a nine meridional segment model for hexachlorocyclohexane. It is suggested that this approach should be applied to Hg, but this is not presently possible because of the lack of data on Hg species properties and conversion rates. Available data have been used to test the hypothesis that lower temperatures cause enhanced partitioning from the atmosphere to a lake ecosystem at low temperatures by compiling a three species model of an atmosphere-water-sediment-fish system at 25 degree C and 0 degree C. Preliminary results show that the effect of this drop in temperature is to cause increases in concentrations throughout the aquatic ecosystem of factors of three to four, other factors being equal. Thus it is likely that a comprehensive global model will show that Hg is subject to the global fractionation phenomenon. It is recommended that attempts be made to develop such a model.
AN: 3799838
241 of 1521
TI: The role of microorganisms in elemental mercury formation in natural waters
AU: Mason,-R.P.; Morel,-F.M.M.; Hemond,-H.F.
AF: Chesapeake Biol. Lab., Solomons, MD 20688, USA
CO: 3. International Conference on Mercury as a Global Pollutant, Whistler, BC (Canada), 10-14 Jul 1994
SO: THIRD-INTERNATIONAL-CONFERENCE-ON-MERCURY-AS-A-GLOBAL-POLLUTANT. Porcella,-D.;Huckabee,-J.;Wheatley,-B.-eds. 1995 vol. 80, no. 1-4 pp. 775-787
ST: WATER,-AIR,-SOIL-POLLUT. vol. 80, no. 1-4
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Gas evasion of elemental Hg (Hg degree ) from the open ocean plays a prominent role in the global mercury cycle. Elemental Hg is formed primarily by reduction of ionic Hg in the mixed layer of aquatic systems. By culturing phytoplankton in defined media, and by incubating natural seawater and freshwater samples, we have demonstrated that Hg degree is produced by microorganisms, with formation rates (0.5 to 10%) similar to those estimated from mass balance studies. Our results also suggest that <3 mu m microorganisms are the primary Hg reducers in natural waters. Eucaryotic phytoplankton are capable of reducing ionic Hg to Hg degree but the rate of reduction is insufficient to account for the observed reduction rates found in incubated field samples. Bacteria are thus the more likely Hg reducers. In seawater, cyanobacteria such as Synecococcus may account for much of the mercury reduction, while in the eutrophic, polluted Upper Mystic Lake north of Boston other procaryotic microorganisms are contributing to the overall Hg reductive capacity of the medium. By reducing ionic Hg, microorganisms play a pivotal role in the aquatic biogeochemistry of Hg, not only by enabling evasion to the atmosphere, but by directly decreasing the amount of ionic Hg available for methylation.
AN: 3796202
242 of 1521
TI: Dimethylmercury and dimethylmercury-sulfide of microbial origin in the biogeochemical cycle of Hg
AU: Baldi,-F.; Parati,-F.; Filippelli,-M.
AF: Dip. Biol. Ambient., Univ. Siena Via P.A. Mattioli 4, I-53100 Siena, Italy
CO: 3. International Conference on Mercury as a Global Pollutant, Whistler, BC (Canada), 10-14 Jul 1994
SO: THIRD-INTERNATIONAL-CONFERENCE-ON-MERCURY-AS-A-GLOBAL-POLLUTANT. Porcella,-D.;Huckabee,-J.;Wheatley,-B.-eds. 1995 vol. 80, no. 1-4 pp. 805-815
ST: WATER,-AIR,-SOIL-POLLUT. vol. 80, no. 1-4
LA: English
ER: M (Marine)
AB: The transformation of MeHg under anaerobic conditions in axenic cultures of Desulfovibrio desulfuricans strain LS is compared to that in anoxic marine sediments contaminated by Hg of industrial origin. MeHg was added to cultures of D. desulfuricans strain LS and incubated at 28 degree C for two weeks. Significant amounts of dimethylmercury and metacinnabar were produced. These two Hg compounds were formed from the slow decomposition of the intermediate dimethylmercury-sulfide. Other collateral compounds, such as methane and ionic Hg, were also detected during the MeHg degradation process. On the other hand a sample of fresh sediment (1.5 g d.w.) was spiked with 10 mu g of MeHg and 2 mmoles.ml super(-1) of pyruvate, as carbon source for sulfate-reducing bacteria. After 9 days of incubation at 28 degree C, significant amounts of dimethylmercury were produced. A lower content of this volatile species was found in a subsample of sediment supplemented with sodium molybdate, which is a strong inhibitor of sulfate-reducing activity. A kinetic study showed the disappearance of monomethylmercury from the sediment and the formation of dimethylmercury over the incubation period. The environmental significance of dimethylmercury and dimethylmercury-sulfide in the natural biogeochemical cycle of Hg is discussed.
AN: 3796198
243 of 1521
TI: Mercury cycling in the Allequash Creek watershed, northern Wisconsin
AU: Krabbenhoft,-D.P.; Benoit,-J.M.; Babiarz,-C.L.; Hurley,-J.P.; Andren,-A.W.
AF: U.S. Geol. Survey, Water Resour. Div., Madison, WI 53719, USA
CO: 3. International Conference on Mercury as a Global Pollutant, Whistler, BC (Canada), 10-14 Jul 1994
SO: THIRD-INTERNATIONAL-CONFERENCE-ON-MERCURY-AS-A-GLOBAL-POLLUTANT. Porcella,-D.;Huckabee,-J.;Wheatley,-B.-eds. 1995 vol. 80, no. 1-4 pp. 425-433
ST: WATER,-AIR,-SOIL-POLLUT. vol. 80, no. 1-4
LA: English
ER: F (Freshwater)
AB: Although there have been recent significant gains in our understanding of mercury (Hg) cycling in aquatic environments, few studies have addressed Hg cycling on a watershed scale. In particular, attention to Hg species transfer between watershed components (upland soils, groundwater, wetlands, streams, and lakes) has been lacking. This study describes spatial and temporal distributions of total Hg and MeHg among watershed components of the Allequash Creek watershed (northern Wisconsin, USA). Substantial increases in total Hg and MeHg were observed as groundwater discharged through peat to form springs that flow into the stream, or rivulets that drain across the surface of the wetland. This increase was concomitant with increases in DOC. During fall, when the Allequash Creek wetland released a substantial amount of DOC to the stream, a 2-3 fold increase in total Hg concentrations was observed along the entire length of the stream. Methylmercury, however, did not show a similar response. Substantial variability was observed in total Hg (0.9 to 6.3) and MeHg (<0.02 to 0.33) concentrations during synoptic surveys of the entire creek. For the Allequash Creek watershed, the contributing groundwater basin is about 50% larger than the topographic drainage basin. Total Hg concentrations in groundwater, the area of the groundwater basin, and annual stream flow data give a watershed-yield rate of 1.2 mg/km super(2)/d, which equates to a retention rate of 96%. The calculated MeHg yield rate for the wetland area is 0.6 to 1.5 mg/km super(2)/d, a value that is 3-6 fold greater than the atmospheric deposition rate.
AN: 3796179
244 of 1521
TI: Methylated and elemental mercury cycling in surface and deep ocean waters of the North Atlantic
AU: Mason,-R.P.; Rolfhus,-K.R.; Fitzgerald,-W.F.
AF: Chesapeake Biol. Lab., Univ. Maryland, Solomons, MD 20688, USA
CO: 3. International Conference on Mercury as a Global Pollutant, Whistler, BC (Canada), 10-14 Jul 1994
SO: THIRD-INTERNATIONAL-CONFERENCE-ON-MERCURY-AS-A-GLOBAL-POLLUTANT. Porcella,-D.;Huckabee,-J.;Wheatley,-B.-eds. 1995 vol. 80, no. 1-4 pp. 665-677
ST: WATER,-AIR,-SOIL-POLLUT. vol. 80, no. 1-4
LA: English
ER: M (Marine)
AB: Biogeochemical cycling of mercury (Hg) in the ocean and air-sea exchange are integral parts of the global Hg cycle. Ionic Hg (i.e. reactive Hg-Hg super(o)) is converted in ocean surface waters to elemental Hg (Hg super(o)) with the subsequent loss, via gas evasion, of the Hg super(o) to the atmosphere. During a recent cruise in the North Atlantic Ocean, Hg super(o) in surface waters was a substantial fraction of the reactive Hg (85%, on average) and there was a relationship between photosynthetic pigment concentration and Hg super(o). In addition, there was evidence of Hg bound to "collodial" material (of greater than 1,000 molecular weight). Ionic Hg concentrations were around 0.15 pM, similar to the average colloidal Hg concentration of 0.2 pM. Methylated Hg compounds, both dimethylHg (DMHg) and monomethylHg (MMHg), were found in the deeper waters with DMHg being the predominant methylated species. This contrasts with freshwater lakes where MMHg is the principal species and no DMHg has been found. Preliminary modelling, using estimated rate constants for the formation and decomposition of DMHg and MMHg, predicts an enhanced stability of DMHg in ocean waters relative to fresh water. Deep ocean waters, formed by sinking of surface waters, can preserve DMHg that was produced in the more productive surface regime.
AN: 3796172
245 of 1521
TI: Mercury cycling in the water column of a seasonally anoxic urban lake (Onondaga Lake, NY)
AU: Jacobs,-L.A.; Klein,-S.M.; Henry,-E.A.
AF: PTI Environ. Serv., 15375 SE 30th Place, Suite 250, Bellevue, WA 98007, USA
CO: 3. International Conference on Mercury as a Global Pollutant, Whistler, BC (Canada), 10-14 Jul 1994
SO: THIRD-INTERNATIONAL-CONFERENCE-ON-MERCURY-AS-A-GLOBAL-POLLUTANT. Porcella,-D.;Huckabee,-J.;Wheatley,-B.-eds. 1995 vol. 80, no. 1-4 pp. 553-562
ST: WATER,-AIR,-SOIL-POLLUT. vol. 80, no. 1-4
LA: English
ER: F (Freshwater)
AB: Onondaga Lake, New York, is a hypereutrophic, urban lake that was subjected to industrial discharges of mercury (Hg) between 1947 and 1988. Water samples were collected from April through November 1992 and analyzed for filtered and unfiltered total Hg, methylmercury (CH sub(3)Hg), dimethylmercury, ionic Hg, and elemental Hg to characterize the biogeochemical cycling of Hg during water column stratification and hypolimnetic anoxia. In the spring and late fall when the water column was isothermal, total Hg and CH sub(3)Hg concentrations were relatively constant throughout the water column, at approximately 3-7 ng/L and 0.3-1 ng/L, respectively. Through the summer and early fall, CH sub(3)Hg concentrations systematically increased in the deeper waters, reaching peak concentration in August and September. In September 1992, CH sub(3)Hg concentrations increased from 0.3 ng/L in the epilimnion to 10.6 ng/L in the hypolimnion, an increase of nearly 2 orders of magnitude. At the same time, total Hg increased from 6.6 ng/L in surface water to 21.7 ng/L at depth, a 3-fold increase. The spatial and temporal patterns observed for CH sub(3)Hg agree well with manganese, suggesting that CH sub(3)Hg and manganese are controlled by processes of the same or parallel cycles.
AN: 3796159
246 of 1521
TI: Microbial activity and phosphorus dynamics in eutrophic lake sediments enriched with Microcystis colonies
AU: Brunberg,-A.-K.
AF: Inst. Limnol., Uppsala Univ., Norbyvaegen 20, S-752 36 Uppsala, Sweden
SO: FRESHWAT.-BIOL. 1995 vol. 33, no. 3, pp. 541-555
LA: English
ER: F (Freshwater)
AB: Sediments from hypereutrophic Lake Vallentunasjoen were enriched with Microcystis colonies from the lake water, thereby simulating the conditions after the autumn sedimentation. Release of phosphorus to the overlying lake water was followed during 2-3 weeks in the laboratory. X-ray microanalysis of individual Microcystis and bacterial cells, and chemical phosphorus fractionation, were used to assess the phosphorus pool size in different fractions of the sediment. Release of molybdate-reactive phosphorus to the overlying lake water was larger from sediment cores enriched with Microcystis colonies than from control cores. X-ray microanalysis showed that the phosphorus bound in Microcystis cells decreased by -0.300 mg g super(-1) DW in the October experiment, due both to a decrease in biomass (i.e. mineralization) and to a decrease in phosphorus content in the remaining cells.
AN: 3794300
247 of 1521
TI: A first-order nutrient budget for the tropical Moresby Estuary and catchment, north Queensland, Australia
AU: Eyre,-B.
AF: Cent. Coast. Manage., P.O. Box 5125, East Lismore, N.S.W. 2480, Australia
SO: J.-COAST.-RES. 1995 vol. 11, no. 3, pp. 717-732
LA: English
ER: B (Brackish)
AB: Dry and wet season phosphorus and nitrogen budgets for the Moresby Estuary and catchment are constructed to interpret cause-effect relationships between catchment landuse and nutrient loads in the coastal waterways of the Great Barrier Reef region. Samples were collected during seasonal extremes to reflect as wide a range of conditions as possible. Smaller scale processes cannot be resolved at this level of nutrient balance due to large budget uncertainties. However, the nutrient budget does give an insight into catchment scale processes. Fertilizer application on cane land in the catchment is the dominant source of phosphorus (about 3,566 plus or minus 735 x 10 super(3) moles) and nitrogen (about 79,330 plus or minus 11,338 x 10 super(3) moles), contributing 88 times more phosphorus and nitrogen to the catchment than is supplied by other sources (e.g., septic tanks, atmospheric fallout, natural runoff and natural springs). However, only about 4 plus or minus 2% of the phosphorus and about 11 plus or minus 7% of the nitrogen added to the catchment is transferred to the estuary. About 82% of the phosphorus and about 90% of the nitrogen flux from the catchment occurs during the wet season. Once in the estuary, only small amounts of phosphorus and nitrogen are retained with most of the phosphorus being transferred to the ocean and it is suggested that most of the nitrogen may be used biologically. The fact that the Moresby Estuary is not a strong sink for nutrients (i.e., it is not becoming eutrophic with time) suggests that current levels of agricultural activity in the catchment can be maintained without adverse effects on ecological components of the estuary and catchment.
AN: 3794066
248 of 1521
TI: Nitrogen uptake and regeneration in a frontal region of the Algerian current (western Mediterranean Sea): New evaluation of new production
OT: Absorption et regeneration de l'azote dans la zone frontale du courant Algerien (Mediterranee Occidentale): Reevaluation de la production nouvelle
AU: Gentilhomme,-V.; Raimbault,-P.
AF: Cent. Oceanol. Marseille, Observatoire Sci. Univers, Fac. Sci. Luminy, Case 901, 13288 Marseille Cedex 9, France
SO: OCEANOL.-ACTA 1995 vol. 17, no. 5, pp. 555-562
LA: English
ER: M (Marine)
AB: The uptake and regeneration of 4 forms of nitrogen have been studied in the euphotic layer of a frontal area in relation with hydrological, chemical and biological parameters. In this area vertical stratification is pronounced; a deep chlorophyll maximum at the bottom of the euphotic layer is present. Results show the importance of measuring urea uptake and regeneration in the study of nitrogen cycling, because the component can be regenerated as rapidly as ammonia, and is source of nitrogen for phytoplankton. Other results show the oxidation of ammonia to nitrate in the euphotic layer. This nitrification is a source of in situ regeneration nitrate and could lead to a wrong estimation of the new production estimation. In the deep chlorophyll maximum, there is a maximum of nitrogen primary production but not a maximum of new production. Regenerated production is the most important process over the whole euphotic layer of the Algerian basin.
AN: 3788993
249 of 1521
TI: Biodegradability of organic matter in the water column and fluid mud of the Loire estuary
OT: Biodegradabilite de la matiere organique dans le bouchon vaseux et la creme de vase de l'estuaire de la Loire
AU: Maurice,-L.
AF: IFREMER Cent. Toulon, DEL, BP 330, 83507 La Seyne/Mer, France
SO: OCEANOL.-ACTA 1995 vol. 17, no. 5, pp. 501-516
LA: English
ER: M (Marine); B (Brackish)
AB: The organic matter trapped in the turbidity maximum zone of the Loire estuary, as a support of bacterial activity, constitutes a basic element in the biogeochemical cycle which permits us to understand the causes of the anoxia observed in September. The anaerobic fluid mud is presumed to be the centre of fermentation and/or hydrolysis processes; the formation rate of dissolved organic carbon (DOC) in this layer reaches 3 g C.m super(-3). D super(-1). When particles in the water column, the organic products formed in the fluid mud are integrated into the aerobic metabolic cycle and contribute to the decrease of dissolved oxygen concentrations. The fluid mud participates in ammonia regeneration in the turbidity maximum zone. Causes of the anoxia cannot be studied without a thorough knowledge of the transformation processes of organic and mineral components in the fluid mud.
AN: 3788989
250 of 1521
TI: Fe, Zn, Mn and N transfer between size classes in a coastal phytoplankton community: Trace metal and major nutrient recycling compared
AU: Hutchins,-D.A.; Bruland,-K.W.
AF: Mar. Sci. Res. Cent., SUNY Stony Brook, Stony Brook, New York, NY 11794-5000, USA
SO: J.-MAR.-RES. 1995 vol. 53, no. 2, pp. 297-313
LA: English
ER: M (Marine)
AB: Experiments were performed to investigate transfer of super(59)Fe, super(65)Zn, super(54)Mn, and super(15)N from labeled cyanobacteria to the large (> 8 mu m or > 5 mu m) phytoplankton size class from Monterey Bay, California. Transfer of metal isotope activity was measured from and into total (for all isotopes) and intracellular ( super(59)Fe only) pools. Results demonstrated rapid and efficient transfer of nitrogen to the large phytoplankton size class; intracellular super(59)Fe was transferred into the intracellular and total pools of the > 8 mu m phytoplankton size class 70% and 130% as efficiently as nitrogen, respectively. super(65)Zn and super(54)Mn were transferred between size classes 48% and 23% as efficiently as N. Extracellular super(59)Fe and super(65)Zn from the added cyanobacteria also appeared quickly in the large size fraction, although most of the Fe transfer appeared to be the result of surface adsorption rather than biological uptake. These data are discussed in relation to the biological recycling efficiencies of the four elements and the resulting implications for biogeochemical cycling of trace and major nutrient elements.
AN: 3788841
251 of 1521
TI: On the organic carbon maximum on the continental slope of the eastern Arabian Sea
AU: Calvert,-S.E.; Pedersen,-T.F.; Naidu,-P.D.; Von-Stackelberg,-U.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada
SO: J.-MAR.-RES. 1995 vol. 53, no. 2, pp. 269-296
LA: English
ER: M (Marine)
AB: We critically examine the hypothesis that the oxygen minimum in the eastern Arabian Sea is the site of enhanced organic matter accumulation and preservation using analyses of suites of samples with wide geographical coverage along this margin. The distribution of organic matter on the western Indian continental margin is controlled by (1) variations in supply (decreasing westward away from the centers of coastal upwelling and also decreasing with increasing water depth), (2) dilution by other sedimentary components, and (3) the texture of the sediments (coarser-grained sediments having lower carbon contents), which is controlled in turn by sediment supply and reworking. The evidence available suggests that the organic carbon maximum on this slope is not related to the position of the oxygen minimum.
AN: 3788840
252 of 1521
TI: Computer modelling of phosphatic surfaces
AU: Suharan,-S.; Taylor,-M.G.; Simkiss,-K.
AF: Sch. Anim. and Microb. Sci., Dep. Zool., Univ. Reading, Reading RG6 2AJ, UK
CO: 7. Int. Symp. on Biomineralization, Monaco (Monaco), 17 Nov 1993
SO: BIOMINERALIZATION-'-93.-1.-FUNDAMENTALS-OF-BIOMINERALIZATION. Allemand,-D.;Cuif,-J.P.-eds. MONACO-MONACO INSTITUT-OCEANOGRAPHIQUE 1994 vol. NS 14, no. 1 pp. 81-84
ST: MEM.-INST.-OCEANOGR.-MONACO vol. NS 14, no. 1
LA: English
ER: M (Marine); F (Freshwater)
AB: Calcium phosphates in the form of inorganic granules are released into the marine environment by many marine invertebrates in faecal pellets which become part of the marine phosphate cycle. This cycle can result in the long term increase or decrease of phosphates in the environment. The key to any quantitative evaluation of the fate of these particles and their effect on the phosphate cycle is to predict reactions at the surface of these pellets. The approach used here is to develop a potential model for atomistic type simulations of the bulk and surface structures of crystalline calcium phosphates which will be transferable to the granules.
AN: 3787738
253 of 1521
TI: Evaluation of the physicochemical state of heavy metals in Danube water in various stretches
AU: Linnik,-P.N.; Osadchaya,-N.N.; Nabivanets,-Y.B.; Evtushenko,-N.Y.
AF: Inst. Hydrobiol., Ukrainian Acad. Sci., Ukraine
SO: WATER-RESOUR.;VODNYE-RESURSY 1994;1993 vol. 20, no. 4, pp. 48-55;vol. 20, no. 4, pp. 449-454
NT: Special issue: Investigation of the Danube River ecosystem.
LA: English
ER: F (Freshwater)
AB: Among pollutants contained in wastewaters, heavy metals (HMs) occupy one of the first places in toxicity. As is known, they are not subject to biodegradation and, gradually accumulating in various components of the ecosystem, participate in biological cycles. The chemical reactivity and biological activity of HMs are determined not so much by their gross concentrations as by the physicochemical state in the aquatic environment. Works on estimating the content of HMs in the Ukrainian stretch of the Danube began in the late 1970s. Profound studies of coexisting forms of HMs have been being carried out since 1980. Two international expeditions were conducted in March 1988 and September-October 1990, which made it possible to characterize the state of HMs in various stretches of the river.
AN: 3787430
254 of 1521
TI: Benthic microbial production of oxygen supersaturates the bottom water of a stratified hypersaline lake
AU: Burke,-C.M.
AF: Dep. Aquacult., Univ. Tasmania at Launceston, P.O. Box 1214, Tasmania 7250, Australia
SO: MICROB.-ECOL. 1995 vol. 29, no. 2, pp. 163-171
LA: English
AB: Lake Hayward is a hypersaline lake that stratifies seasonally and maintains oxygen supersaturation in its bottom water for about 6 months each year. This phenomenon was found to be the result of photosynthesis by the benthic microbial communities, composed primarily of the cyanobacteria Cyanothece spp., Spirulina sp., and Oscillatoria sp. When these communities were present and the lake was stratified, the bottom water was supersaturated with oxygen. During illumination, the benthic microbial communities rapidly developed very high concentrations of oxygen, which then diffused into the overlying water. However, while the overlying water became supersaturated, the concentration in the water was lower than in the benthic microbial communities because (1) transport across the sediment-water interface was limited by diffusion, and (2) turbulence rapidly mixed the oxygen throughout the much larger volume of the bottom water.
AN: 3787391
255 of 1521
TI: Spatial and seasonal patterns in sediment nitrogen remineralization and ammonium concentrations in San Francisco Bay, California
AU: Caffrey,-J.M.
AF: U.S. Geol. Surv., 345 Middlefield Rd, MS 496, Menlo Park, CA 94025, USA
SO: ESTUARIES 1995 vol. 18, no. 1B, pp. 219-233
LA: English
ER: B (Brackish)
AB: Nitrogen remineralization and extractable ammonium concentrations were measured in sediments from several locations in North and South San Francisco bays. In South Bay, remineralization rates decreased with depth in sediment and were highest in the spring following the seasonal phytoplankton bloom. At the channel stations, peak remineralization lagged peak water-column phytoplankton biomass (as measured by chlorophyll a) by a month. Remineralization rates were generally higher in South Bay than North Bay. The lower remineralization rates in North Bay may be a result of anomalously low phytoplankton production and thus reduced deposition to the sediments, as well as low riverine organic inputs to the upper estuary in recent years. Remineralization rates were positively correlated to carbon and nitrogen content of the sediments. In general, ammonium profiles in South Bay sediments showed no increase in deeper (4-8 cm) sediments. In North Bay, ammonium concentrations were greatest at stations with highest remineralization rates, and, in contrast to South Bay, extractable ammonium increased in deeper sediment. Differences in ammonium pools between North Bay and South Bay may be a result of increased irrigation by deep-dwelling macrofauna, which are more abundant in South Bay.
AN: 3787028
256 of 1521
TI: Organic matter fluxes and marsh stability in a rapidly submerging estuarine marsh
AU: Nyman,-J.A.; DeLaune,-R.D.; Pezeshki,-S.R.; Patrick,-W.H.,Jr.
AF: Dep. Biol., P.O. Box 42451, Univ. Southwestern Louisiana, Lafayette, LA 70504-2451, USA
SO: ESTUARIES 1995 vol. 18, no. 1B, pp. 207-218
LA: English
ER: B (Brackish)
AB: We studied organic matter cycling in two Gulf Coast tidal, nonsaline marsh sites where subsidence causes marine intrusion and rapid submergence, which mimics increased sea-level rise. The sites experienced equally rapid submergence but different degrees of marine intrusion. Vegetation was hummocked and much of the marsh lacked rooted vegetation. Aboveground standing crop and production, as measured by sequential harvesting, were low relative to other Gulf Coast Spartina patens marshes. Soil bulk density was lower than reported for healthy S. alterniflora growth but that may be unimportant at the current, moderate sulfate levels. Belowground production, as measured by sequential harvesting, was extremely fast within hummocks, but much of the marsh received little or no belowground inputs. Aboveground production was slower at the more saline site (681 g m super(2)/yr) than at the less saline site (1,252 g m super(2)/yr). Belowground production over the entire marsh surface averaged 1,401 g m super(2)/yr at the less saline site and 585 g m super(2)/yr at the more saline site. Respiration, as measured by CO sub(2) emissions in the field and corrected for CH sub(4) emissions, was slower at the less saline site (956 g m super(2)/yr) than at the more saline site (1,438 g m super(2)/yr), reflecting greater contributions by S. alterniflora at the more saline site which is known to decompose more rapidly than S. patens. Burial of organic matter was faster at the less saline site (796 g m super(2)/yr) than at the more saline site (434 g m super(2)/yr), likely in response to faster production and slower decomposition at the less saline site. Thus vertical accretion was faster at the less saline site (1.3 cm/yr) than at the more saline site (0.85 cm/yr); slower vertical accretion increased flooding at the more saline site. More organic matter was available for export at the less saline site (1,377 g m super(2)/yr) than at the more saline site (98 g m super(2)/yr). These data indicated that organic matter production decreased and burial increased in response to greenhouse-like conditions brought on by subsidence.
AN: 3787027
257 of 1521
TI: Inputs, transformations, and transport of nitrogen and phosphorus in Chesapeake Bay and selected tributaries
AU: Boynton,-W.R.; Garber,-J.H.; Summers,-R.; Kemp,-W.M.
AF: Univ. Maryland Syst., Cent. Environ. Estuar. Stud., Chesapeake Biol. Lab., Box 38, Solomons, MD 20688, USA
SO: ESTUARIES 1995 vol. 18, no. 1B, pp. 285-314
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: In this paper we assemble and analyze quantitative annual input-export budgets for total nitrogen (TN) and total phosphorus (TP) for Chesapeake Bay and three of its tributary estuaries (Potomac, Patuxent, and Choptank rivers). The budgets include estimates of TN and TP sources (point, diffuse, and atmospheric), internal losses (burial in sediments, fisheries yields, and denitrification), storages in the water column and sediments, internal cycling rates (zooplankton excretion and net sediment-water flux), and net downstream exchange. Our budgets indicate that the annual mass balance of TN and TP is maintained by a net landward exchange of TP and, with one exception (Choptank River), a net seaward transport of TN. The budgets for all systems revealed that inorganic nutrients entering these estuaries from terrestrial and atmospheric sources are rapidly converted to particulate and organic forms. Discrepancies between our budgets and others in the literature were resolved by the inclusion of sediments derived from shoreline erosion. The greatest potential for errors in our budgets can be attributed to the absence of or uncertainties in estimates of atmospheric dry-fall, contributions of nutrients via groundwater, and the sedimentation rates used to calculate nutrient burial rates.
AN: 3786954
258 of 1521
TI: Elemental ratios and the uptake and release of nutrients by phytoplankton and bacteria in three lakes of the Canadian Shield
AU: Elser,-J.J.; Chrzanowski,-T.H.; Sterner,-R.W.; Schampel,-J.H.; Foster,-D.K.
AF: Dep. Zool., Arizona State Univ., Tempe, AZ 85287, USA
SO: MICROB.-ECOL. 1995 vol. 29, no. 2, pp. 145-162
LA: English
ER: F (Freshwater)
AB: The dynamics of carbon (C), nitrogen (N), and phosphorus (P), elemental ratios, and dark uptake/release of N and P in bacterial and phytoplankton size fractions were studied during summer 1992 in three lakes of contrasting food web structure and trophic status. The authors wished to determine if phytoplankton and bacteria differed in their elemental characteristics and to evaluate whether the functional role of bacteria in nutrient cycling (i.e., as sink or source) depended on bacterial elemental characteristics. Bacterial contributions to total suspended particulate material and to fluxes of nutrients in the dark were substantial and varied for different elements. This indicated that some techniques for assaying phytoplankton physiological condition are compromised by bacterial contributions. C/N ratios were generally less variable than C/P and N/P ratios.
AN: 3786575
259 of 1521
TI: The role of bacteria in the nutrient exchange between sediment and water in a flow-through system
AU: Kairesalo,-T.; Tuominen,-L.*; Hartikainen,-H.; Rankinen,-K.
AF: Dep. Limnol. and Environ. Prot., P.O. Box 27, FIN-00014 Univ. Helsinki, Finland
SO: MICROB.-ECOL. 1995 vol. 29, no. 2, pp. 129-144
LA: English
ER: F (Freshwater)
AB: The contribution of bacteria to phosphorus and nitrogen release from, or retention in, sediment was studied in a flow-through system. "Live" and formaldehyde-"killed" sediment communities were incubated in 25-liter bottles with a continuous flow of P- or P + N-enriched water. Sediment bacteria in the killed communities were inhibited by adding formaldehyde to the sediment before the start of the experiment. Bacterial activity in the live sediments measured with [ super(3)H]thymidine and [ super(14)C]leucine incorporation techniques did not change essentially during the experiment period (7-8 days). Chemical mechanisms were found to be of principal importance in PO sub(4)-P retention in the sediment. In the live samples, the net retention of PO sub(4)-P was lower than in the killed samples, which was likely due to the reduced O sub(2) conditions in the sediment as a consequence of bacterial mineralization. In total P exchange, however, bacteria increased the retention rate by recycling dissolved organic P in the sediment.
AN: 3786574
260 of 1521
TI: Seasonal patterns of nitrification and denitrification in a natural and a restored salt marsh
AU: Thompson,-S.P.; Paerl,-H.W.; Go,-M.C.
AF: Univ. North Carolina, Inst. Mar. Sci., 3431 Arendell St., Morehead City, NC 28557, USA
SO: ESTUARIES 1995 vol. 18, no. 2, pp. 399-408
LA: English
ER: M (Marine); B (Brackish)
AB: Seasonal patterns of microbially-mediated nitrogen cycling via the nitrification-denitrification pathway were compared between a natural and a restored salt marsh. Sedimentary denitrification rates, measured with a modification of the acetylene block technique, were approximately 44 times greater in the natural marsh relative to an adjacent transplanted marsh. Nitrification rates were similar at both sites. The difference in denitrification rates was attributed to oxygen inhibition at low tide and tidal flushing of porewater nutrients at high tide in the coarse sediments of the restored marsh. Denitrification was positively correlated with nitrification throughout the year in the natural marsh with a seasonal fall peak in denitrification corresponding to a maximum in porewater ammonia concentration. A weak correlation existed between the two processes in the restored marsh, where nitrification rates exceeded denitrification rates by a factor of 20. Transplanted marsh denitrification rates exhibited a spring peak, corresponding to elevated porewater ammonia concentrations. Our findings demonstrate functional differences in microbial nitrogen dynamics of a young (0-3 yr) restored marsh relative to a mature (>50 yr) salt-marsh system.
AN: 3785336
261 of 1521
TI: Cyclic and secular variation in microfossil biomineralization: Clues to the biogeochemical evolution of Phanerozoic oceans
AU: Martin,-R.E.
AF: Dep. Geol., Univ. Del., Newark, DE 19716, USA
SO: GLOBAL-PLANET.-CHANGE 1995 vol. 11, no. 1-2, pp. 1-23
LA: English
ER: M (Marine)
AB: The stratigraphic occurrence and mineralogy of major protistan microfossil taxa tend to reflect evolutionary innovation in response to ocean chemistry and fertility. In foraminifera, the characteristic test composition-and, in some cases, ultrastructure-of each suborder is indicative of the degree of surface ocean CaCO sub(3) saturation, which varied in a cyclic manner through the Phanerozoic, at the time of origin of the suborder. High dissolve phosphate and low CaCO sub(3) saturation in late Precambrian-Early Cambrian surface waters may have prevented calcification in primitive non-calcareous (organic, agglutinated) foraminiferal stocks. Scattered reports of coccolithophorid-like microfossils from the Paleozoic are indicative of a secular trend in rising nutrient levels and marine productivity that controlled the initiation of calcareous oozes. Based on acritarch, carbon isotope, and phosphorite records, extremely low nutrient levels ("superoligotrophic" conditions) in Cambrian-to-Devonian seas typically limited population densities of calcareous nannoplankton and prevented the formation of calcareous oozes. The overall "superoligotrophic" surface conditions of the Paleozoic were punctuated, though, by episodes of "catastrophic" eutrophication in the Late Ordovician, Late Devonian, and Late Carboniferous (Worsley et al., 1986). Following each episode, CaCO sub(3) rain rates were presumably enhanced because Marine C:P (MCP) burial ratios increased permanently above previous levels (Worsley et al., 1986). Nevertheless, it was not until the Carboniferous that the CCD had deepened sufficiently (via erosion of cratonic limestones) to allow pelagic calcareous oozes to begin to accumulate. Prior to this time, surface waters appear to have been sufficiently corrosive (high atmospheric pCO sub(2) and low CaCO sub(3) saturation), and the CCD sufficiently shallow, to dissolve virtually all incipient calcareous nannofossils. Following Late Permian extinctions, plankton re-expanded in response to both eustatic sea level rise (increased habitat availability) and increased nutrient levels ("mesotrophic" conditions). As organic matter (C sub(org)) and CaCO sub(3) rain rates increased, bioturbation rates also increased, thereby recycling nutrients back to the surface and accentuating productivity and calcareous ooze formation. MCP episodes further accelerated nutrient cycling and productivity in the Neogene, as indicated by the expansion of diatoms, which prefer nutrient-rich ("eutrophic") conditions. Ironically, while permanently increasing C:P burial ratios and productivity through the Phanerozoic, catastrophic fluctuations in nutrient levels may have also exacerbated mass extinctions via shortening of pelagic food chains. Nevertheless, re-expansion of the marine biosphere following each extinction episode resulted in a secular trend of increasing biomass and biotic diversity that may have contributed to the decline in background extinction rates through the Phanerozoic.
AN: 3785193
262 of 1521
TI: Sediment-water fluxes of inorganic nitrogen compounds along the transport route of organic matter in the North Sea
AU: Lohse,-L.; Malschaert,-J.F.P.; Slomp,-C.P.; Helder,-W.; Van-Raaphorst,-W.
AF: Netherlands Inst. Sea Res., P.O. Box 59, 1790 AB Den Burg, Netherlands
CO: International Symposium on Nutrient Dynamics in Coastal and Estuarine Environments, Helsingoer (Denmark), 13-16 Oct 1993
SO: OPHELIA 1995 vol. 41, pp. 173-197
LA: English
ER: M (Marine)
AB: Sediment-water fluxes of ammonium and nitrate, as well as nitrification and denitrification were measured in different types of sediments in the North Sea in August 1991 and February 1992. Stations were located along the main transport route of organic matter and included depositional areas located on the southern shelf (German Bight) and on the north-eastern shelf-slope transition in the Skagerrak. Based on sedimentary organic carbon content and grain size distribution, the stations were divided into three clusters. I: depositional areas with median grain size <50 mu m; II: transition zones with grain sizes between 80 and 180 mu m, and III: coarse sediments with median grain size >280 mu m. Porewater profiles of nitrate and ammonium corresponded well to this clustering. The very high mineralisation in the German Bight in August demonstrates the importance of deposition of locally produced organic matter in this area. Total ammonium production in the Skagerrak in August and February indicates that here N-cycling is dominated by the input of refractory organic matter from the southern shelf. Consequently, the shelf-slope transition in the Skagerrak does not represent an area of intensified nitrogen mineralisation.
AN: 3785184
263 of 1521
TI: A review of the U.S. Global Change Research Program and NASA's Mission to Planet Earth/Earth Observing System
CA: National Research Counc., Washington, DC (USA)
SO: WASHINGTON,-DC-USA NATIONAL-ACADEMY-PRESS 1995 107 pp
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: This report reflects the results of a July 1995 workshop convened as the first phase of a two-part review of the U.S. Global Change Research Program. The workshop's objective was to conduct an initial assessment of scientific progress to date, and to review the role of NASA's Mission to Plant Earth/Earth Observing System program in the light of budgetary pressures. The report identifies priority issues in four areas of Earth science: seasonal to interannual climate prediction (El Nino, land-atmosphere interactions); atmospheric chemistry (tropospheric and stratospheric ozone, global distribution of aerosols, biogenic gases); ecosystems (global carbon cycle, vegetation-climate-land use interrelationships, oceanic food chain, exchange of water, carbon dioxide and biogenic gases); and decadal to centennial climate (forcing factors influencing climate, ocean-land-atmosphere-ice processes, long-term monitoring).
AN: 3779381
264 of 1521
TI: A global model for the early diagenesis of organic carbon and organic phosphorus in marine sediments
AU: Tromp,-T.K.; Van-Cappellen,-P.; Key,-R.M.
AF: Atmos. and Environ. Res., Inc., 840 Memorial Dr., Cambridge, MA 02139, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 7, pp. 1259-1284
LA: English
ER: M (Marine)
AB: Sediments are the main repository in the oceanic cycles of carbon (C) and phosphorus (P). In order to relate the deposition of organic C and organic P from the water column, and ultimate burial in sediments, we present a model for the early diagenesis of organic matter in marine sediments. This general diagenetic model was developed for inclusion in global circulation models and is based on a single master variable, the sedimentation rate. The processes included are sediment advection, particle mixing by bioturbation, porewater diffusion, organic matter degradation by aerobic respiration, sulfate reduction, and methanogenesis. Despite the model's simplicity, the model quantitatively reproduces the rates of organic matter oxidation and the burial fluxes of organic C and P. The predicted trends of oxygen penetration depth and the relative importance of oxygen and sulfate reduction are in good agreement with field observations.
AN: 3777848
265 of 1521
TI: Reservoir timescales for anthropogenic CO sub(2) in the atmosphere
AU: O'-Neill,-B.C.; Gaffin,-S.R.; Tubiello,-F.N.; Oppenheimer,-M.
AF: Dep. Earth Syst. Sci., NYU, New York, NY 10003, USA
SO: TELLUS-B-CHEM.-PHYS.-METEOROL. 1994 vol. 46B, no. 5, pp. 378-389
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Non-steady state timescales are complicated and their application to specific geophysical systems requires a common theoretical foundation. We first extend reservoir theory by quantifying the difference between turnover time and transit time (or residence time) for time-dependent systems under any mixing conditions. We explicitly demonstrate the errors which result from assuming these timescales are equal, which is only true at steady state. We also derive a new response function which allows the calculation of age distributions and timescales for well-mixed reservoirs away from steady state, and differentiate between timescales based on gross and net fluxes. These theoretical results are particularly important to tracer-calibrated "box models" currently used to study the carbon cycle, which usually approximate reservoirs as well-mixed. We then apply the results to the important case of anthropogenic CO sub(2) in the atmosphere, since timescales describing its behavior are commonly used but ambiguously defined. All relevant timescales, including lifetime, transit time, and adjustment time, are precisely defined and calculated from data and models. Apparent discrepancies between the current, empirically determined turnover time of 30-60 years and longer model-derived estimates of expected lifetime and adjustment time are explained within this theoretical framework. We also discuss the results in light of policy issues related to global warming, in particular since any comparisons of the "lifetimes" of different greenhouse gases (CO sub(2), CH sub(4), N sub(2)O, CFC's etc.) must use a consistent definition to be meaningful.
AN: 3777834
266 of 1521
TI: Influence of changes in CO sub(2) concentration and temperature on marine phytoplankton super(13)C/ super(12)C ratios: An analysis of possible mechanisms
AU: Raven,-J.A.; Johnston,-A.M.; Turpin,-D.H.
AF: Dep. Biol. Sci., Univ. Dundee, Dundee DD1 4HN, UK
SO: GLOBAL-PLANET.-CHANGE 1993 vol. 8, no. 1-2, pp. 1-12
NT: Special issue: Ocean carbon cycle and climate change.
LA: English
ER: M (Marine)
AB: The super(13)C/ super(12)C fractionation associated with net transport fluxes and chemical conversions, and with equilibria, associated with inorganic C assimilation processes in marine phytoplankton are quite well understood, though some gaps remain. These values are used in models of overall super(13)C/ super(12)C fractionation in inorganic C assimilation involving the two major mechanisms involved in inorganic C entry, i.e. diffusion of CO sub(2) and active transport of CO sub(2) and/or HCO sub(3) super(-). The CO sub(2) diffusion model predicts the observed decrease in the super(13)C/ super(12)C of plankton organic C relative to source CO sub(2) when CO sub(2) concentration increases and/or temperature decreases. The inorganic C active transport model is complicated by repression of the active transport mechanism at high inorganic C levels, but this model also predicts the observed effect on cell super(13)C/ super(12)C of changes in CO sub(2) partial pressure or temperature for cell growth. More refined modelling and more input data are needed for both transport processes. Operation of either of the alternative mechanisms for inorganic C entry can be consistent with growth rate not being limited by inorganic C supply even when the photosynthetic rate is inorganic C-limited.
AN: 3775648
267 of 1521
TI: Chemical tracers of biological processes in shallow waters of North Pacific: Preformed nitrate distributions
AU: Emerson,-S.; Hayward,-T.L.
AF: Sch. Oceanogr., WB-10, Univ. Washington, Seattle, WA 98195, USA
SO: J.-MAR.-RES. 1995 vol. 53, no. 3, pp. 499-513
LA: English
ER: M (Marine)
AB: Distributions of nitrate and Apparent Oxygen Utilization in the upper subtropical North Pacific Ocean reveal a layer with negative values of preformed nitrate. This layer occurs at depths just below the 1% light level and above the density of sigma theta 25.6. We show that large-scale spatial patterns in the distribution of this feature are determined by an interaction between light penetration and the depth of isopycnal surfaces which are ventilated in nutrient rich surface waters. The geographic and depth distributions of the negative preformed nitrate feature are most readily explained by respiration of nitrogen-poor dissolved organic matter (DOM) from the surface ocean with the possible accompaniment of nitrate uptake. Dissolved organic carbon gradients and transport calculations suggest that a significant fraction of the carbon flux out of the euphotic zone may be via DOM, indicating that the processes responsible for creating the negative preformed nitrate feature could alter the metabolite stoichiometry in upper subtropical Pacific Ocean.
AN: 3773841
268 of 1521
TI: Seasonal variability of light availability and utilization in the Sargasso Sea
AU: Siegel,-D.A.; Michaels,-A.F.; Sorensen,-J.C.; O'-Brien,-M.C.; Hammer,-M.A.
AF: Inst. Comput. Earth Syst., Univ. California, Santa Barbara, CA 93106, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1995 vol. 100, no. C5, pp. 8695-8713
LA: English
ER: M (Marine)
AB: A 2 year time series of optical, biogeochemical, and physical parameters, taken near the island of Bermuda, is used to evaluate the sources of temporal variability in light availability and utilization in the Sargasso Sea. Integrated assessments of light availability are made by examining the depth of constant percent incident photosynthetically available radiation (%PAR) volumes. Determinations of in situ primary production rates and daily mean PAR fluxes are used to diagnose the relative role of light limitation in determining vertically integrated rates of primary production integral of PP. The mean depth of the light-saturated zone (the vertical region where the daily mean PAR flux was greater than or equal to the saturation irradiance I sub(k)) is only similar to 40 m, although more than one half of integral of PP occurred within this zone. Production model results illustrate the accurate predictions of integral of PP are dependent upon rates of light-saturated production rather than upon indices of light limitation. It seems unlikely that significant improvements in simple primary production models will come from the partitioning of the Earth's seas into biogeochemical provinces.
AN: 3773801
269 of 1521
TI: Forms and distribution of inorganic phosphorus in sediments of two shallow eutrophic lakes in Florida
AU: Olila,-O.G.; Reddy,-K.R.; Harris,-W.G.
AF: Univ. Florida, Inst. Food Agric. Sci., Soil Water Sci. Dep., Gainesville, FL 32611, USA
SO: HYDROBIOLOGIA 1995 vol. 302, no. 2, pp. 147-161
LA: English
ER: F (Freshwater)
AB: Phosphorus (P) reactivity and bioavailability in lake sediments may be determined by different forms of P and their distribution. Reactive and nonreactive P pools in two shallow subtropical lake sediments (Lake Apopka and Lake Okeechobee) were determined by sequential chemical extraction using 1 M NH sub(4)Cl (pH 7.0), 0.1 M NaOH, and 0.5 M HCl, reportedly representing loosely-bound P, Fe-and Al-bound P, and Ca- and Mg-bound P respectively. The sequential P fractionation was tested using pure P compounds and selected P minerals. The scheme effectively separated Fe- and Al-P from Ca-P fractions in an FePO sub(4)-AlPO sub(4)-Ca sub(3)(PO sub(4)) sub(2) mixture. Readily available P, defined as the sum of water-soluble P and NH sub(4)Cl-extractable P, in the unconsolidated gyttja (UCG) layer (surface 0-30 cm) of Lake Apopka sediments accounted for 10.1 to 23.7% of total P (TP). This sediment P fraction constitutes a large reservoir which may act as a source of P to the overlying water. In subsurface marl layers (134-148 cm depth) of Lake Apopka, NH sub(4)Cl-P constituted <1% of TP whereas Ca-Mg-bound P and highly resistant P (residual P) accounted for 35 and 64% of TP respectively. Results suggest that 1 M NH sub(4)Cl (pH 7.0) and 0.5 M HCl, reported to dissolve carbonate-bound P and Ca-Mg-bound P, respectively, may not be extracting distinct pools of P. Lake Okeechobee mud sediments had low concentrations of readily available P (2% of TP) and were dominated by Ca-Mg-bound P (HCl-P greater than or equal to 58% of TP). Sediments in the littoral and peat areas of Lake Okeechobee, however, had high concentrations of readily available P (9.7 and 17.4% of TP respectively); hence, these sediments may play an important role in internal P cycling. The NaOH-P (Fe-Al-P) concentrations for Lake Okeechobee sediments were strongly correlated with amorphous and poorly-crystalline Fe (p<0.01), suggesting that some P reactions in these sediments may be sensitive to changes in physico-chemical conditions such as redox potential and sediment resuspension.
AN: 3773206
270 of 1521
TI: Terrestrial and marine biomarkers in a seasonally ice-covered Arctic estuary -- integration of multivariate and biomarker approaches
AU: Yunker,-M.B.; Macdonald,-R.W.; Veltkamp,-D.J.; Cretney,-W.J.
AF: 7137 Wallace Dr., Brentwood Bay, BC V8M 1G9, Canada
SO: MAR.-CHEM. 1995 vol. 49, no. 1, pp. 1-50
LA: English
ER: M (Marine)
AB: Hydrocarbons, including alkanes, alkenes, hopane triterpenes and polycyclic aromatic hydrocarbons, plus sterols, n-alcohols and a number of higher plant triterpenoids have been determined for suspended particulate, sediment trap and sediment samples taken from the Mackenzie River and the adjacent Mackenzie shelf in the Beaufort Sea. These biomarkers are valuable tracers of terrigenous and petrogenic inputs from the river to the shelf water column and are also useful for assessing marine production in the Mackenzie River estuary. We use Principal Component Analysis to provide a robust classification of biomarkers according to their primary source (e.g. terrigenous, marine) and to identify which biomarkers covary. To quantify dispersal of riverine material on the adjacent shelf in the context of dilution by marine production, we develop a multivariate Partial Least Squares (PLS) path model. We find that the PLS results strengthen geochemical interpretations based on individual biomarkers by providing a quantitative representation of the differences among samples.
AN: 3773204
271 of 1521
TI: Hydrochemistry of the Bay of Bengal: Possible reasons for a different water-column cycling of carbon and nitrogen from the Arabian Sea
AU: Rao,-C.K.; Naqvi,-S.W.A.*; Kumar,-M.D.; Varaprasad,-S.J.D.; Jayakumar,-D.A.; George,-M.D.; Singbal,-S.Y.S.
AF: Natl. Inst. Oceanogr., Dona Paula, Goa 403 004, India
SO: MAR.-CHEM. 1994 vol. 47, no. 3-4, pp. 279-290
NT: Special issue: Chemistry of the Northern Indian Ocean.
LA: English
ER: M (Marine)
AB: A study on biogeochemical cycling in the western Bay of Bengal was undertaken during two seasons (pre-southwest monsoon and northeast monsoon of 1991). Relationships of the conservative tracers NO and PO with potential temperature ( Theta ) are used to identify three end-member water masses in the Bay: the low-salinity surface water, the high-salinity intermediate water advecting from the Arabian Sea, and the deep water of circumpolar origin. A hydrochemical discontinuity at similar to 12 degree C appears to define the boundary of zones of linear mixing among these waters. The shallower occurrence of the discontinuity in the Bay as compared to the Arabian Sea appears to restrict the thickness of the oxygen minimum layer in the former region. Marked seasonal changes appear to occur in intermediate waters, presumably reflecting changes in the coastal circulation off India. It is proposed that lower respiration rates in the Bay might result from a rapid sinking of organic matter with relatively little decomposition within the water column caused by the large inputs of terrigenous material.
AN: 3773201
272 of 1521
TI: Deep penetration of sedimentary fluids in basement rocks from southern Norway: Evidence from hydrocarbon and brine inclusions in quartz veins
AU: Munz,-I.A.; Yardley,-B.W.D.; Banks,-D.A.; Wayne,-D.
AF: Mineral.-Geol. Mus., Univ. Oslo, N-0562 Oslo, Norway
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 2, pp. 239-254
LA: English
AB: This paper presents evidence for fluid flow and fluid-rock interaction at upper crustal levels within the crystalline basement of southern Norway. In the high-grade Modum Complex postmetamorphic veins of quartz occur in association with albitisation of metagabbros and metasediments. Pressure-temperature conditions for the formation of these veins are in the range 250-300 degree C and ca. 1-2 kbar. Primary and pseudosecondary fluid inclusions in the quartz veins show two fluids: (1) hydrocarbon plus or minus CO sub(2) inclusions and (2) aqueous inclusions with variable salinities. Dark carbonaceous solid inclusions are also present. The hydrocarbon inclusions are methane dominated (ca. 80-100 mol%), and the presence of higher, complex hydrocarbons is demonstrated. The types and chemistry of the hydrocarbons in these veins indicate a biogenic origin of the hydrocarbon fluids. The inclusion fluids are interpreted as derived from an overlying sedimentary basin in late Precambrian or Permian times. The veining is interpreted as the deep expression of the percolation of basinal fluids into the metamorphic basement during crustal extension.
AN: 3769475
273 of 1521
TI: The effects of water temperature, stratification, and biological activity on the stable isotopic composition and timing of carbonate precipitation in a hypersaline lake
AU: Rosen,-M.R.; Turner,-J.V.; Coshell,-L.; Gailitis,-V.
AF: Inst. Geol. and Nucl. Sci., Wairakei Res. Cent., Priv. Bag 2000, Taupo, New Zealand
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 5, pp. 979-990
LA: English
ER: B (Brackish); F (Freshwater)
AB: The delta super(18)O of carbonate minerals in a seasonally stratified hypersaline lake are > +2.3ppt PDB and are inconsistent with calculated delta super(18)O values for carbonate in equilibrium with the lake water during the spring and winter. The delta super(13)C values of the calcium carbonate minerals precipitated in the lake are heavier than the dissolved inorganic carbon values ( delta super(13)C sub(DIC)) of the lake water and cannot be explained by kinetic fractionation, indicating a biologic control on primary carbonate precipitation. The delta super(13)C of dolomite found in the lake sediments are in equilibrium with porewater delta super(13)C sub(DIC), suggesting a high degree of porewater interaction in dolomitization. Both the delta super(18)O and delta super(13)C compositions of the dolomite suggest that it formed in equilibrium with current porewater but not in equilibrium with the coexisting calcium carbonate minerals.
AN: 3769473
274 of 1521
TI: Glacial enrichments of authigenic Cd and U in Subantarctic sediments: A climatic control on the elements oceanic budget?
AU: Rosenthal,-Y.; Boyle,-E.A.; Labeyrie,-L.; Oppo,-D.
AF: Biosphere 2, Oracle, AZ, USA
SO: PALEOCEANOGRAPHY 1995 vol. 10, no. 3, pp. 395-413
LA: English
ER: M (Marine)
AB: We examine the possibility that glacial increase in the areal extent of reducing sediments might have changed the oceanic Cd inventory, thereby decoupling Cd from PO sub(4). We suggest that the precipitation of Cd-sulfide in suboxic sediments is the single largest sink in the oceanic Cd budget and that the accumulation of authigenic Cd and U is tightly coupled to the organic carbon flux into the seafloor. Sediments from the Subantarctic Ocean and the Cape Basin (South Atlantic), where oxic conditions currently prevail, show high accumulation rates of authigenic Cd and U during glacial intervals associated with increased accumulation of organic carbon. These elemental enrichments attest to more reducing conditions in glacial sediments in response to an increased flux of organic carbon. A third core, overlain by Circumpolar Deep Water (CPDW) as are the other two cores but located south of the Antarctic Polar Front, shows an approximately inverse pattern to the Subantarctic record. The contrasting patterns to the north and south of the Antarctic Polar Front suggest that higher accumulation rates of Cd and U in Subantarctic sediments were driven primarily by increased productivity. This proposal is consistent with the hypothesis of glacial stage northward migration of the Antarctic Polar Front and its associated belt of high siliceous productivity.
AN: 3769355
275 of 1521
TI: Influence of variable rates of neritic carbonate deposition on atmospheric carbon dioxide and pelagic sediments
AU: Walker,-J.C.G.; Opdyke,-B.C.
AF: Space Phys. Res. Lab., Dep. Atmos., Ocean. Space Sci., Univ. Michigan, Ann Arbor, MI, USA
SO: PALEOCEANOGRAPHY 1995 vol. 10, no. 3, pp. 415-427
LA: English
ER: M (Marine)
AB: Short-term imbalances in the global cycle of shallow water calcium carbonate deposition and dissolution may be responsible for much of the observed Pleistocene change in atmospheric carbon dioxide content. However, any proposed changes in the alkalinity balance of the ocean must be reconciled with the sedimentary record of deep-sea carbonates. The possible magnitude of the effect of shallow water carbonate deposition on the dissolution of pelagic carbonate can be tested using numerical simulations of the global carbon cycle. Boundary conditions can be defined by using extant shallow water carbonate accumulation data and pelagic carbonate deposition/dissolution data. On timescales of thousands of years carbonate deposition versus dissolution is rarely out of equilibrium by more than 1.5 x 10 super(13) mole/yr. Results indicate that the carbonate chemistry of the ocean is rarely at equilibrium on timescales less than 10 ka. This disequilibrium is probably due to sea level-induced changes in shallow water calcium carbonate deposition/dissolution, an interpretation that does not conflict with pelagic sedimentary data from the central Pacific.
AN: 3769354
276 of 1521
TI: Chronology for climate change: Developing age models for the Biogeochemical Ocean Flux Study cores
AU: Manighetti,-B.; McCave,-I.N.; Maslin,-M.; Shackleton,-N.J.
AF: Dep. Earth Sci., Univ. Cambridge, Cambridge, UK
SO: PALEOCEANOGRAPHY 1995 vol. 10, no. 3, pp. 513-525
NT: Special Section: The Biogeochemical Ocean Flux Study.
LA: English
ER: M (Marine)
AB: We construct age models for a suite of cores from the northeast Atlantic Ocean by means of accelerator mass spectrometer dating of a key core, BOFS 5K, and correlation with the rest of the suite. The effects of bioturbation and foraminiferal species abundance gradients upon the age record are modeled using a simple equation. The degree of bioturbation is estimated by comparing modeled profiles with dispersal of the Vedde Ash layer in core 5K, and we find a mixing depth of roughly 8 cm for sand-sized material. Using this value, we estimate that age offsets between unbioturbated sediment and some foraminifera species after mixing may be up to 2500 years, with lesser effect on fine carbonate (<10 mu m) ages. The bioturbation model illustrates problems associated with the dating of "instantaneous" events such as ash layers and the "Heinrich" peaks of ice-rafted detritus. Correlations between core 5K and the other cores from the BOFS suite are made on the basis of similarities in the downcore profiles of oxygen and carbon isotopes, magnetic susceptibility, water and carbonate content, and via marker horizons in X radiographs and ash beds.
AN: 3769348
277 of 1521
TI: Bacterial oxidation of methane in the Enisei R. estuary and the Kara Sea.
OT: Bakterial'noe okislenie metana v ehstuarii reki Enisej i karskom more
AU: Namsaraev,-B.B.; Rusanov,-I.I.; Mitskevich,-I.N.; Veslopolova,-E.F.; Bol'-shakov,-A.M.; Egorov,-A.V.
AF: Inst. Mikrobiol. RAN, Moscow, Russia
SO: OKEANOLOGIYA 1991 vol. 35, no. 1, pp. 88-93
LA: Russian
ER: M (Marine); F (Freshwater)
AB: The paper presents tabulated data on the abundance of methane-oxidizing bacteria and the rate of CH sub(4) oxidation in the water and bottom sediments of the Estuary, Yenisey Bay and adjacent Kara Sea areas. The number of methane-oxidizing bacteria amounts to 7900 per ml water. The rate of CH sub(4) oxidation is 0.4-200 nl/l/day in the water column and 4-3300 nl/kg/day in the sediments. The rates are higher in the river and lower in the sea.
AN: 3769036
278 of 1521
TI: Transformation of particle-bound phosphorus at the land-sea interface
AU: Conley,-D.J.; Smith,-W.M.; Cornwell,-J.C.; Fisher,-T.R.
AF: Danmarks Miljoundersogelser, Natl. Environ. Res. Inst., P.O. Box 358, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
SO: ESTUAR.,-COAST.-SHELF-SCI. 1995 vol. 40, no. 2, pp. 161-176
LA: English
ER: M (Marine)
AB: The distribution of phosphorus was examined along the salinity gradient of the Chesapeake Bay estuary during spring and summer in 1989 and 1990. Particulate phosphorus (PP) was the dominant form of phosphorus in the estuary accounting for 23-90% of total phosphorus (TP). Particulate phosphorus was highest in the upper estuary (0.42-1.84 mu M) and rapidly decreased in concentration in the upper bay with only slight decreases observed down-estuary. Dissolved organic phosphorus (DOP) often comprised a somewhat larger fraction of the TP (8-43%) than did dissolved inorganic phosphorus (DIP; 5-40%) with DOP and DIP concentrations highest in bottom waters during summer anoxia. Both DIP and DOP concentrations were maintained at relatively low levels in surface waters by plankton, especially during the spring phytoplankton bloom. The distribution of particle-bound phosphorus in the suspended matter of the Chesapeake Bay was partitioned by a sequential chemical leaching technique into three major fractions: (1) an organic and loosely-bound fraction (Org-P), (2) an iron-associated fraction extracted with citrate-dithionate-bicarbonate (CDB-P), and (3) a detrital (apatite rich) fraction extracted with hydrochloric acid (HCl-P). The particle-bound phosphorus was associated mainly with Org-P (43-61%), followed by CDB-P (32-46%), with HCl-P generally comprising only a small fraction of the total particle-bound phosphorus (5-13%). The majority of changes in the composition of the particle-bound phosphorus occurred early in the transition from fresh- to saltwater with declines in both iron-associated phosphorus (CDB-P) and apatite-associated phosphorus (HCl-P). The ratios of CDB-Fe to CDB-P in suspended matter were relatively low suggesting that the particulate matter of Chesapeake Bay has a low capacity to absorb additional phosphorus through interactions with iron. Biological processes in the bay were much more important to the biogeochemical cycle of phosphorus than in many other estuaries previously examined for phosphorus biogeochemistry. Although inorganic exchange reactions may occur, they do not have the capacity to 'buffer' DIP concentrations throughout the Chesapeake Bay estuary.
AN: 3766313
279 of 1521
TI: Contribution of mathematical modeling to lake ecosystem understanding: Lake Bourget (Savoy, France)
AU: Vincon-Leite,-B.; Tassin,-B.; Jaquet,-J.-M.
AF: CERGRENE, Ec. Natl. Ponts et Chaussees, Ec. Natl. Genie Rural, des Eaux et des Forets, F-93167 Noisy-le-Grand, France
CO: 2. Int. Congress of Limnology and Oceanography, Evian (France), 25-28 May 1993
SO: SPACE-PARTITION-WITHIN-AQUATIC-ECOSYSTEMS. Balvay,-G.-ed. 1995 vol. 300-301 pp. 433-442
ST: HYDROBIOLOGIA vol. 300-301
LA: English
ER: F (Freshwater)
AB: This paper demonstrates how mathematical modeling can contribute to improve understanding of lake behavior. Since the 60's Lake Bourget, one of the largest in France, had been suffering from eutrophication which was checked in 1980 by the diversion of the main sewers entering the lake. A research program was implemented between 1987 and 1990, including an on-site sampling campaign conducted concurrently with thermal and biogeochemical modeling of lake behavior. The model helped provide a better understanding of the ecosystem, displaying some processes hitherto misunderstood: (1) Winter overturn does not reach the bottom of the water column when the weather is mild. This leads to a incomplete reoxygenation of the hypolimnion and to redox conditions inducing the release of orthophosphate from the sediment, (2) Grazing by herbivorous zooplankton is getting more important in the control of spring algal growth as eutrophication of the lake regresses, (3) Settling of particulate phosphorus seems a complex and very important process in Lake Bourget, showing high sedimentation rates for particulate mineral phosphorus.
AN: 3765417
280 of 1521
TI: Examination through a principal component analysis of the phosphorus exchanges between sediments and water in trophically different reservoirs
AU: Mhamdi,-M.A.; Aleya,-L.*; Devaux,-J.
AF: Lab. Zool. Protistol., URA CNRS 138, 63177 Aubiere Cedex, France
CO: 2. Int. Congress of Limnology and Oceanography, Evian (France), 25-28 May 1993
SO: SPACE-PARTITION-WITHIN-AQUATIC-ECOSYSTEMS. Balvay,-G.-ed. 1995 vol. 300-301 pp. 383-389
ST: HYDROBIOLOGIA vol. 300-301
LA: English
ER: F (Freshwater)
AB: Phosphorus exchange at the sediment-water interface coupled with several parameters were assessed in several reservoirs with geologically different catchment basins and different trophic status in Morocco and France. The results showed that these exchanges were regulated by a combination of factors: physical chemical variability of the environment, the geological composition of catchment basins and the trophic status of the lake. In the hypereutrophic Villerest, iron-bound phosphorus is the major form of phosphorus trapped by the sediment whereas, in Moroccan reservoirs, calcium-bound phosphorus prevailed. We suggest that a drastic control of phosphorus inputs into the waters must be done through a large program of dephosphatization of tributaries to avoid Microcystis aeruginosa bloom formation in Villerest (Aleya et al., 1993) and calcium-bound phosphorus dissociation in Moroccan reservoirs with upward release of bioavailable phosphorus.
AN: 3765381
281 of 1521
TI: Is there a downward transport of organic matter associated with dial vertical migrations of animals in the ocean?
AU: Tsejtlin,-V.B.
AF: IORAN, Moscow, Russia
SO: RUSS.-J.-AQUAT.-ECOL.-ZH.-VODN.-EHKOL. 1992 vol. 1, no. 1, pp. 73-79
LA: English
ER: M (Marine)
AB: The paper considers two possible means of downward organic matter transport by planktonic animals performing vertical migrations: 1) transport of organic matter in the tissues of the migrants bodies; and 2) transport with the migrants faeces. The magnitude of transport in the first case is calculated as the difference between the consumption of the migrants by predators at a lower depth and the proportion of their own food intake at this depth. It is shown that even if a small portion of the diurnal food intake is consumed in deeper waters, the transport of organic matter by this means is negligible. The maximum C sub(org) flux produced by the migrants does not exceed 8% of that produced by sinking detritus. In the second case the transport is possible only with the faeces of macroplanktonic animals and constitutes only a very small fraction of the detritus flux from above.
AN: 3765112
282 of 1521
TI: Impact of pressure on bacterial activity in water columns situated at the European continental margin
AU: Poremba,-K.
AF: Inst. Meereskd., Univ. Kiel, D-24105 Kiel, FRG
SO: NETH.-J.-SEA-RES. 1994 vol. 33, no. 1, pp. 29-35
LA: English
ER: M (Marine)
AB: The vertical profiles of bacterial abundance and activity were measured in water columns situated at the European continental margin of the Celtic Sea in July 1993 and January 1994. The stations lay in the middle of a submarine canyon (depth: 3713 m) and at the base of the continental slope (depth: 4480 m). The bacterial numbers were counted using epifluorescence microscopy, the cell multiplication was determined as super(3)H-thymidine uptake, the accumulation of proteinaceous biomass was measured as super(3)H-leucine uptake, and the impact of pressure on bacterial activity was studied in experiments under pressure conditions between 1 and 450 atm. In upper water layers or in July, the ratio of leucine uptake compared to thymidine uptake was generally higher than in deep layers or in January. The populations of all water layers generally preferred their in situ pressure, especially in July, while in January the barotolerance of the upper communities in 10 to 150 m water depth increased. A comparison of per-cell activity under in situ pressure showed that cells close to the bottom occasionally possessed higher specific activities than in the euphotic water layer. These findings indicate that the performance of experiments under elevated pressure is highly recommended, if the detection of phenomena such as those shown here in the deep sea is wanted.
AN: 3764984
283 of 1521
TI: Paleoclimatic history of Devils Lake, North Dakota: Final report
AU: Lyons,-W.B.
CA: Mackay Sch. of Mines, Reno, NV (USA)
SO: REP.-U.S.-GEOL.-SURV.-WATER-RESOUR.-DIV. 1991 32 pp
NT: NTIS Order No.: PB91-168963/GAR.
RN: USGS/G-1655 (USGSG1655)
LA: English
ER: F (Freshwater)
AB: Analyses were made on a series of sediment, porewater and groundwater samples in and around the Devils Lake, N.D. region in order to: (1) establish a short term (i.e. approx. 500yr) climatic record, (2) determine the relationship between hydrologic forcing and the lake's biological response, (3) calculate a chemical budget for the lake waters and (4) understand the influence of the Spiritwood Aquifer on the overall lake system. Data indicate that the sediments of the lake provide a detailed paleohydrologic and paleobiological record of the lake. Biogenic silica correlates extremely well with changes in lake level and therefore represents an extremely sensitive indicator of the paleohydrology of the drainage basin. Time series analyses of the sediment data demonstrates a close correlation between in-situ lake biological activity and the approx. 11 yr sun spot cycle. Geochemical budget of the lake suggests that the lake sediments are an important source of solutes to the lake waters especially at high stand periods. The groundwater analyses show that the major recharge to the Spiritwood Aquifer is probably from winter precipitation. (DBO)
AN: 3757852
284 of 1521
TI: Coupling of strontium and calcium cycles in Lake Constance
AU: Stabel,-H.-H.
AF: Water Control Res. Lab., ZV Bodensee-Wasserversorgung, D-7770 Uberlingen, FRG
CO: 4. Symp. on Sediment/Water Interactions, Melbourne (Australia), 16-20 Feb 1987
SO: SEDIMENT-WATER-INTERACTIONS. Sly,-P.G.;Hart,-B.T.-eds. 1989 vol. 176-177 pp. 323-329
ST: HYDROBIOLOGIA vol. 176-177
LA: English
ER: F (Freshwater)
AB: The contents of Sr and Ca were measured weekly in Lake Constance in 1986. Epilimnetic concentrations of Ca changed between 1.30 x 10 super(-3) mol/l (during homothermy) and 0.9 x 10 super(-3) mol/l (during thermal stratification). The seasonal fluctuations of Ca were correlated with those of Sr (between 4.61 and 5.36 mu mol/l). The epilimnion was permanently oversaturated with respect to calcite but not with respect to SrCo sub(3). Analysis of the settling process by use of sedimentation traps revealed two short episodes of very high authigenic settling fluxes of CaCO sub(3), triggered by phytoplankton diatoms. Seasonal changes of the Ca contents (between 4.1 and 30.7 percent of the dry weight) and of the Sr concentrations (from 12 to 75 x 10 super(-3) percent) in the settling material were closely correlated. This suggests a coprecipitation mechanism with a nearly constant stoichiometry of (atoms Sr/atoms Ca) x 1000 of 0.84. Coprecipitation of Sr or Ca with organic matter was insignificant. In the hypolimnion some Sr and Ca were released from the settling material. These results strongly suggest that the cycle of Sr in Lake Constance is driven predominantly by coprecipitation with calcite. The principal chemical mechanisms leading to coprecipitation are discussed. (DBO)
AN: 3757721
285 of 1521
TI: Seasonal variations in the loosely sorbed phosphorus fraction of the sediment of a shallow and hypereutrophic lake
AU: Soendergaard,-M.
AF: Bot. Inst. Univ. Aarhus, Nordlandsuej 68, 8240 Risskov, Denmark
CO: 4. Symp. on Sediment/Water Interactions, Melbourne (Australia), 16-20 Feb 1987
SO: SEDIMENT-WATER-INTERACTIONS. Sly,-P.G.;Hart,-B.T.-eds. 1989 vol. 176-177 pp. 321-322
ST: HYDROBIOLOGIA vol. 176-177
LA: English
ER: F (Freshwater)
AB: On the basic of selective extractions loosely sorbed phosphorus (ADS-P) has been shown to constitute much of the total phosphorus in the P-rich near-surface sediments of Lake Sobygaard, Denmark. The concentrations of ADS-P are seasonally variable, ranging from 0.2 mg P/g DW in the winter to more than 2 mg P/g DW in the summer. The variations can be observed as deep as 10 cm into the sediment but are most pronounced in the upper few centimeters. During the summer lake and pore water pH levels are very high, and photosynthetic activity causes elevation to pH 10-11 in the lake Laboratory experiments demonstrated a strong association between ADS-P and high pore water pH. It is likely that Lake Sobygaard represents an extreme example of pH control on sediment/water phosphorus equilibria in which high concentrations of internal ADS-P contribute significantly to the total P load of the lake. (DBO)
AN: 3757720
286 of 1521
TI: Use of radionuclides in the study of contaminant cycling processes
AU: Santschi,-P.H.
AF: Dep. Mar. Sci., Texas A&M Univ., Galveston, TX 77553-1675, USA
CO: 4. Symp. on Sediment/Water Interactions, Melbourne (Australia), 16-20 Feb 1987
SO: SEDIMENT-WATER-INTERACTIONS. Sly,-P.G.;Hart,-B.T.-eds. 1989 vol. 176-177 pp. 307-320
ST: HYDROBIOLOGIA vol. 176-177
LA: English
AB: Of all the geochemical boundaries, the sediment-water interface can exert the greatest control on the cycling of many elements in shallow aquatic environments such as lakes, rivers, estuaries and coastal embayments and, to a lesser extent in the deep sea. Across this interface, the gradients in physical properties (i.e. density), in chemical conditions (i.e. pH, pE, ligand concentrations), biota abundance (i.e. fauna and flora living near the interface) are large, thus producing potentially large fluxes. Some of the physical, chemical, biological and sedimentary controls operating at or near these interfaces can be deciphered from the measurements of natural radioisotopes (e.g. U/Th series or cosmic-ray produced), bomb fallout isotopes or, most recently, fallout from the Chernobyl-reactor accident. Commercially available, reactor-produced isotopes are most often used in enclosures to elucidate the coupling of the various processes at the sediment-water interface, while the former are used both as geochronological tools in the sediments and as tracers to measure or calibrate the rates of exchange across this interface of nutrients or trace elements associated with water or particles. Applications of radioisotopes for studying biological, physical, chemical and sedimentary processes near the sediment-water interface are discussed. In particular, multitracer approaches to study the dynamic coupling of physical, chemical and biological transport processes in lakes are emphasized. Examples from two hard-water lakes in Switzerland, Lake Biel and Lake Zurich, give evidence for the resuspension of fine ('rebound') particles, radionuclides and trace metals from the horizontal boundaries focussing them to their final repositories in the interior of the lake. (DBO)
AN: 3757719
287 of 1521
TI: Heavy metals in eelgrass (Zostera marina L.) during growth and decomposition
AU: Lyngby,-J.E.; Brix,-H.
AF: Water Qual. Inst., 11, Agern Alle, DK-2970 Hoersholm, Denmark
CO: 4. Symp. on Sediment/Water Interactions, Melbourne (Australia), 16-20 Feb 1987
SO: SEDIMENT-WATER-INTERACTIONS. Sly,-P.G.;Hart,-B.T.-eds. 1989 vol. 176-177 pp. 189-196
ST: HYDROBIOLOGIA vol. 176-177
LA: English
ER: B (Brackish)
AB: The distributions of cadmium, chromium, lead, and zinc in eelgrass were studied in samples collected from the field, and the loss/accumulation of the metals during decomposition of eelgrass leaves was studied in laboratory experiments. Concentrations of heavy metals in the below grounds parts were greater in the roots than in the different age groups of the rhizomes. In the rhizomes, the highest concentrations of lead were recorded in the oldest parts, whereas highest chromium and zinc concentrations were found in the youngest parts. The concentration of cadmium did not vary. In the above ground parts, the concentrations of cadmium, lead, and zinc increased with age of the leaves, and concentrations in the leaves were greater than in the stem fraction. The concentrations of chromium decreased with age of the leaves. In the laboratory study of decomposition of leaf material, the concentrations of chromium, lead and zinc increased significantly and a net absorption from the surrounding water was recorded. Cadmium concentrations were relatively constant and a loss of cadmium was proportional to the release of soluble organic compounds indicating an association of cadmium with the soluble phase. The investigation demonstrated the utility of compositional analyses and decomposition experiments in assessing the significance of eelgrass in the heavy metal cycling in coastal areas. Furthermore, significant differences in the fate of heavy metals associated with eelgrass detritus are discussed. (DBO)
AN: 3757708
288 of 1521
TI: [General limnology]
OT: Limnologie generale
AU: Pourriot,-R.; Meybeck,-M.
SO: COLL.-ECOL. PARIS-FRANCE MASSON 1995 200 pp
LA: French
ER: F (Freshwater)
AB: The first part of this paper deals with physical and chemical limnology (study of lakes and basins, the water dynamic, the organic matter, the lacustrine sediments). The second part is devoted to biological limnology (growth and dynamics of algal populations, planktonic and benthic invertebrates, and fish; community structure and organization; trophic relationships (food webs) and predation effects). The third part deals with biogeochemical cycles: the carbon cycle, oxygen cycle and balance, nitrogen and phosphorus cycles, and ecosystem modeling.
AN: 3756627
289 of 1521
TI: Biochemistry of mercury in estuaries and in coastal waters
OT: Biogeochimie du mercure en milieu estuarien et cotier
AU: Coquery,-M.
CA: Paris 6 Univ. (France)
SO: PARIS-FRANCE UNIVERSITE-PARIS-6 1994 270 pp
NT: Thesis (Doct. Oceanologie Meteorologie Environnement).
LA: French
ER: M (Marine); B (Brackish)
AB: The distribution and speciation of mercury was determined in three stratified Arctic estuaries (Lena, Ob and Yenisei), three macrotidal European estuaries (Loire, Seine and Elbe) and in the North Sea. Concentrations in Arctic rivers were among the lowest ever measured. In macrotidal estuaries, contamination is higher in the Seine and in the Elbe than in the Loire. The distribution between dissolved and particulate mercury shows the predominance of the particulate phase. Concentrations of elemental mercury were related to primary production in coastal waters of the Loire and the Seine. Elemental mercury and dimethyl mercury were detected in the low oxygen zone of the Seine Estuary. Concentrations of particulate monomethyl mercury in the Loire were higher in fresh and marine waters than within the high turbidity zone of the estuary.
AN: 3756494
290 of 1521
TI: Simulation of O sub(2), PO sub(4) and organic carbon behavior during a benthic chamber experiment on the deep sea floor
AU: Rabouille,-C.; Gaillard,-J.-F.
AF: Lab. Geochim. Eaux, Univ. Paris 7, Inst. Phys. Globe, 2 Place Jussieu, 75251 Paris Cedex 05, France
SO: OCEANOL.-ACTA 1994 vol. 17, no. 4, pp. 405-416
LA: English
ER: M (Marine)
AB: Using a time-dependent model for organic matter mineralization by oxygen and the resulting phosphate production in deep-sea sediments, the progress of a benthic chamber experiment is simulated.The vertical distribution of chemical species in the sediments, pore water and solids, and the concentrations in the benthic chamber are calculated. The results of the calculations show that the concentration gradients of solutes at the sediment-water interface and the penetration depth of O sub(2) in the sediment undergo important changes during the deployment of a benthic chamber. The model is further used to perform numerical experiments and the different techniques used to calculate fluxes (linear regression, zero-order model) are compared.
AN: 3756490
291 of 1521
TI: C sub(32)-C sub(36) polymethyl alkenes in Black Sea sediments
AU: Damste,-J.S.S.; Erkes,-A.-M.W.E.P.; Rijpstra,-W.I.C.; De-Leeuw,-J.W.; Wakeham,-S.G.
AF: Netherlands Inst. Sea Res. (NIOZ), Div. Mar. Biogeochem., P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 2, pp. 347-353
LA: English
ER: M (Marine)
AB: A series of novel C sub(32)-C sub(36) polymethylhentriacontenes has been identified in near-surface sediments of the Black Sea. Hydrogenation of these components indicated that they possess the 5,8,14,24,27-pentamethyl-, 8,14,24,27-tetramethyl-, 8,14,24-trimethyl-, 8,14-dimethyl-, and 14- and 15-methylhentriacontane C skeletons, which was confirmed by synthesis of an authentic standard of the C sub(34) member. The dominant C sub(36) member of this series contains eight double bonds. The super(13)C content of these polymethylhentricontenes indicated that they are probably biosynthesized by photoautotrophs and that blooming or bicarbonate pumping affected the super(13)C content of the fixed C. Their structures suggest that they were biosynthesized by methylation of an unsaturated n-C sub(31) precursor at specific positions in a well-defined sequence. This biosynthetic pathway represents an alternative for the biosynthesis of isoprenoid-like components.
AN: 3756348
292 of 1521
TI: Carbon-sulfur plots to show diagenetic and epigenetic sulfidation in sediments
AU: Leventhal,-J.S.
AF: U.S. Geol. Surv., Fed. Cent., MS 973, Denver, CO 80225, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 6, pp. 1207-1211
LA: English
ER: M (Marine)
AB: Organic carbon vs. sulfide sulfur plots are now being used regularly by many geochemists to help understand recent and ancient depositional environments and diagenetic processes. Usually, these plots are useful to recognize nonmarine vs. marine environments or oxic vs. anoxic vs. euxinic depositional environments. However, C vs. S plots can also indicate diagenetic and epigenetic events that produce "excess" sulfide. Four new examples are presented and discussed.
AN: 3756345
293 of 1521
TI: CO sub(2) cycling in the coastal ocean. 1. A numerical analysis of the southeastern Bering Sea with applications to the Chukchi Sea and the northern Gulf of Mexico
AU: Walsh,-J.J.; Dieterle,-D.A.
AF: Dep. Mar. Sci., Univ. South Florida, St. Petersburg, FL 33701, USA
SO: PROG.-OCEANOGR. 1994 vol. 34, no. 4, pp. 335-392
LA: English
ER: M (Marine)
AB: A quasi-two dimensional model of the carbon and nitrogen cycling above the 70m isobath of the southeastern Bering Sea at 57 degree N replicates the observed seasonal cycles of nitrate, ammonium, capital sigma CO sub(2), pCO sub(2), light penetration, chlorophyll, phytoplankton growth rate, and primary production, as constrained by changes in wind, incident radiation, temperature, ice cover, vertical and lateral mixing, grazing stress, benthic processing of phytodetritus and zooplankton fecal pellets, and the pelagic microbial loop of DOC, bacteria, and their predators. About half of the seasonal resupply of nitrate stocks to their initial winter conditions is derived from in situ nitrification, with the rest obtained from deep-sea influxes. Under the present conditions of atmospheric forcing, shelf-break exchange, and food web structure, this shelf ecosystem serves as a sink for atmospheric CO sub(2), with storage in the forms of exported DOC, DIC, and unutilized POC (phytoplankton, bacteria, and fecal pellets). As a consequence of just the rising levels of atmospheric pCO sub(2) since the Industrial Revolution, however, the biophysical CO sub(2) status of the Southeastern Bering Sea shelf may have switched over the last 250 years, from a prior source to the present sink, since this relatively pristine ecosystem has undergone little eutrophication. Such fluctuations of CO sub(2) status may thus be reversed by the physical processes of: (1) reduction of atmospheric pCO sub(2), (2) increased onwelling of deep-sea capital sigma CO sub(2), and (3) warming of shelf waters. Based on our application of this model to the Chukchi Sea and the Gulf of Mexico, about 1.0-1.2 gigatons C y super(-1) of atmospheric CO sub(2) may now be sequestered by temperate and polar shelf ecosystems. When tropical systems are included, however, a positive net sink of only 0.6-0.8 x 10 super(15)g C/y may prevail over all shelves.
AN: 3755736
294 of 1521
TI: Use of aspartic acid racemization and post-bomb super(14)C to reconstruct growth rate and longevity of the deep-water slit shell Entemnotrochus adansonianus
AU: Goodfriend,-G.A.; Kashgarian,-M.; Harasewych,-M.G.
AF: Geophys. Lab., Carnegie Inst. Washington, 5251 Broad Branch Rd. NW, Washington, DC 20015-1305, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 6, pp. 1125-1129
LA: English
ER: M (Marine)
AB: Slit shells are living fossils which inhabit the continental slope. Aspartic acid racemization in the nacreous layer of the slit shell Entemnotrochus adansonianus is shown to occur at a remarkably high rate, sufficient to provide annual resolution of the ages of samples taken along the growth spiral of the shells, thus providing information on growth rates and longevity. Calibration of the racemization rate was obtained by super(14)C analysis of a post-bomb specimen. The form of the racemization curve was determined by a heating experiment at 60 degree C; a cubic transformation of the D/L values was found to be linear with respect to time. In three specimens in which a detailed series of samples was analyzed, juvenile growth was found to be very rapid and adult growth 1-2 orders of magnitude slower; adulthood is reached in 2-4 years. Analysis of lip and apical samples of additional shells (total n = 9) shows that individuals reaching adulthood have life spans averaging six years (maximum: 14 yr). The life histories of these deep-water gastropods are thus similar to littoral taxa. Analysis of the prismatic layer shows that this racemizes at a much slower rate than the nacreous layer.
AN: 3754322
295 of 1521
TI: Comment on "Aspartic acid racemization and protein diagenesis in corals over the last 350 years" by G.A. Goodfriend, P.E. Hare, and E.R.M. Druffel
AU: Brinton,-K.L.F.; Bada,-J.L.
AF: Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093-0212, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 2, pp. 415-416
LA: English
ER: M (Marine)
AB: Goodfriend (1992) and Goodfriend et al. (1992) have reported that aspartic acid (Asp) racemizes markedly faster in land snail and coral samples <350 years BP in comparison to older samples. They suggest that the differing racemization rates of protein-bound vs. free Asp residues explain the observed nonlinear racemization kinetics and propose that the initial rapid racemization could provide an important tool for dating of young samples. The samples of Goodfriend (1992) and Goodfriend et al. (1992) were hydrolyzed in 6 N HCl at 100 degree C to yield free amino acids. Under these hydrolysis conditions, asparagine (Asn) undergoes quantitative deamidation to Asp. Therefore, the land snail and coral results represent the combined racemization of Asp and Asn (Asx). Goodfriend himself noted in an earlier paper (Goodfriend, 1991) that the sum of the racemization rates of Asp and Asn under hydrolysis conditions is nonlinear, and he suggested that Asn may racemize faster than Asp. The amount of Asn relative to Asp in the proteins contained in the carbonate matrix of land snails and corals is not known. We therefore suggest that the nonlinear racemization observed for Asx by Goodfriend et al. (1992a,b) could have been caused by the rapid racemization of Asn in comparison to that of Asp.
AN: 3754319
296 of 1521
TI: Reply to the Comment by K.L.F. Brinton and J.L. Bada on "Aspartic acid racemization and protein diagenesis in corals over the last 350 years"
AU: Goodfriend,-G.A.; Hare,-P.E.
AF: Geophys. Lab., Carnegie Inst. Washington, 5251 Broad Branch Rd., NW, Washington, DC 20015-1305, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 2, pp. 417-418
LA: English
ER: M (Marine)
AN: 3754318
297 of 1521
TI: Application of LP-ICP-MS to benthic foraminifers
AU: Wu,-Guoping; Hillaire-Marcel,-C.
AF: Cent. Rech. Geochim. Isot. et Geochronol. (GEOTOP), Univ. Quebec Montreal, Montreal, PQ H3C 3P8, Canada
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 2, pp. 409-414
LA: English
ER: M (Marine)
AB: A laser microprobe coupled with an inductively coupled plasma mass spectrometer (LP-ICP-MS) was used to determine Mg, Mn, Sr, and Ba contents of benthic foraminifers in the solid state. Calcite shells of Cibicides wuellerstorfi, Oridorsalis umbonatus, Pyrgo spp., and aragonite tests of Hoeglundina elegans, which were taken from the surface sediments of the northwestern North Atlantic Ocean, were ablated by a laser beam. Multiple measurements were achieved on single tests since the diameters of ablation pits (20-50 mu m) are significantly smaller than those of the shells ( similar to 250 mu m). Mg/Ca, Mn/Ca, and Ba/Ca of the ablated materials are significantly affected by Fe-Mn oxide coatings and extraneous Ba-bearing phases, and Sr/Ca is not noticeably influenced by those contaminants. There is no substantial variation of Sr/Ca within and between shells of a foraminiferal species. On the contrary, Sr/Ca is species-dependent: Sr/Ca of Pyrgo spp. is three times as high as that of H. elegans, and nearly twice as high as those of C. wuellerstorfi and O. umbonatus.
AN: 3754317
298 of 1521
TI: Significance of colloids in the biogeochemical cycling of organic carbon and trace metals in the Venice Lagoon (Italy)
AU: Martin,-J.-M.; Dai,-Min-Han; Cauwet,-G.
AF: Inst. Biogeochim. Mar., Unite Assoc. CNRS No. 386, 1, Rue Maurice Arnoux, 92120 Montrouge, France
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 1, pp. 119-131
LA: English
ER: M (Marine)
AB: Colloidal organic C and trace metals from the waters of a highly productive coastal environment (the Venice Lagoon, Italy) have been separated by a cross-flow ultrafiltration device. On average, 18% of organic C, 34% of Cd, 46% of Cu, 87% of Fe, 18% of Ni, 58% of Pb, and 54% of Mn which previously would have been considered in the dissolved phase are actually associated with colloidal material. Thus, past studies overestimate the dissolved trace-metal concentration in the nearshore environment. Compared to total concentration, the proportion of the colloidal fraction represents on average 15% of organic C, 18% of Cd, 28% of Cu, 11% of Fe, 11% of Ni, 29% of Pb, and 12% of Mn. This fraction acts differently from the truly dissolved and macroparticulate phases. The behavior of organic C and trace elements during mixing between freshwater and seawater is more complicated than expected when a colloidal fraction is involved. The flocculation of colloids, encountered normally during estuarine mixing, is not very significant on the time scale of mixing in the lagoon. Conversely, the interaction between colloidal and truly dissolved phases seems important. The partitioning of trace metals between different fractions of organic C appears variable, Fe and Mn are preferentially tied to macroparticulate organic matter, and Cu and Cd are preferentially tied to colloidal organic matter in seawater. Truly dissolved organic C appears to be important for Ni. Pb is mainly associated with macroparticulate organic matter at most stations except in the highly productive region where Pb prefers colloidal organic C.
AN: 3754310
299 of 1521
TI: Nitrate reductase activity quantitatively predicts the rate of nitrate incorporation under steady state light limitation: A revised assay and characterization of the enzyme in three species of marine phytoplankton
AU: Berges,-J.A.; Harrison,-P.J.
AF: Build. 318, Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 1, pp. 82-93
LA: English
ER: M (Marine)
AB: The enzyme nitrate reductase (NR) has been proposed as an index of nitrate incorporation rates in marine phytoplankton, but it has proven difficult to interpret NR measurements in field settings because many previous NR assays have been poorly optimized and NR activity in phytoplankton has been poorly characterized under steady state conditions. An NR assay was developed for the diatom Thalassiosira pseudonana using an extraction in phosphate buffer with Triton X-100, EDTA, dithiothreitol, polyvinyl pyrrolidone, and bovine serum albumin. NR activity in homogenates was stable for up to 1 h, but filtered samples could be stored for 96 h in liquid nitrogen without significant loss of activity. Addition of FAD to crude extracts of T. pseudonana had no effect, whereas the effect on desalted extracts or crude extracts from other species, varied from decreases in NR activity to over 250% increases. Half-saturation constants (K sub(m)) varied between species; high levels of NADH or nitrate were found to be inhibitory in some cases. These results indicate a wide diversity of forms of NR in marine phytoplankton. Under continuous, light-limited growth, NR activity was quantitatively related to calculated rates of nitrate incorporation ( mu sub(N)) in T. pseudonana, Skeletonema costatum, and three other diatom species examined. The relationship differed for 10 other species; NR activity was equal to mu sub(N) in some cases, but higher or lower in others. In dinoflagellates, in particular, NR activity was highly correlated with mu sub(N), but accounted for <20% of mu sub(N) in Amphidinium carterae.
AN: 3754307
300 of 1521
TI: A re-assessment of Redfield correlations between dissolved iodine and nutrients in oceanic waters and a strategy for further investigations of iodine
AU: Truesdale,-V.W.
AF: 36, Ladycroft Park, Blewbury, Oxon OX11 9QW, UK
SO: MAR.-CHEM. 1994 vol. 48, no. 1, pp. 43-56
LA: English
ER: M (Marine)
AB: The use of the Redfield nutrient model to explain the behaviour of iodine in the oceanic water column is re-assessed using a rigorous theoretical approach together with existing hydrographic information. It is shown that tests of the model's applicability need to be based upon stations which display a marked turning point in their nutrient profile. Stations that do not, e.g. North and South Atlantic, should be avoided. The earlier use of mixtures of the two types is shown to have biased the conclusion in favour of a fit with Redfield. Reasons are given for believing that, in comparison with the plant nutrients, a greater proportion of iodine is re-cycled in the shallow domain of the profile. The possible correlations between inorganic iodine and the Redfield variables are considered from both theoretical and empirical standpoints.
AN: 3754270
301 of 1521
TI: Phosphate sorption in superficial intertidal sediments
AU: Van-Raaphorst,-W.; Kloosterhuis,-H.T.
AF: Netherlands Inst. Sea Res. (NIOZ), P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: MAR.-CHEM. 1994 vol. 48, no. 1, pp. 1-16
LA: English
ER: M (Marine)
AB: The influence of sorption on phosphorus cycling in intertidal sediments was examined by measuring sorption characteristics (isotherms, kinetics) and sediment content of exchangeable PO sub(4) (extracted with 0.1 M NaOH). The latter contents were highly correlated with Fe-oxides and showed a seasonal pattern with highest values in autumn and winter, and lowest in spring and early summer. Part of the PO sub(4) produced through mineralization in late summer and autumn is stored through sorption in the oxic sediment layers and becomes available to e.g. primary producers in the next season. Sorption experiments showed linear isotherms with adsorption coefficients between 6.9 and 22.7 ml/g. Slow PO sub(4) release due to mineralization of organic matter was visible after c. 50 h of incubation. We applied a dynamic model to correct the sorption data for mineralization and to estimate the sorption kinetics. The first order sorption rates obtained were between 0.7 and 5 ml/g/h. When applying the film model for the upper 5 mm of the sediments, measured fluxes and PO sub(4) gradients could only be reproduced with unrealistically high diffusion coefficients. Diffusion coefficients close to molecular diffusion were obtained by using a simple reaction-diffusion model including the data on sorption kinetics. This model indicates that the transfer of PO sub(4) at the sediment-water interface is enhanced by the sorption reaction and that high fluxes can be maintained at low pore water concentrations in the upper millimeters of the sediment. We conclude that the sorption kinetics together with diffusion control the PO sub(4) concentration in the superficial intertidal sediments.
AN: 3754253
302 of 1521
TI: Photosynthetic fractionation of super(13)C and concentrations of dissolved CO sub(2) in the Central Equatorial Pacific during the last 255,000 years
AU: Jasper,-J.P.; Hayes,-J.M.; Mix,-A.C.; Prahl,-F.G.
AF: Dep. Mar. Sci., Univ. Connecticut, New Haven, CT 06050, USA
SO: PALEOCEANOGRAPHY 1994 vol. 9, no. 6, pp. 781-798
LA: English
ER: M (Marine)
AB: Carbon isotopically based estimates of CO sub(2) levels have been generated from a record of the photosynthetic fractionation of super(13)C ( identical with epsilon sub(p)) in a central equatorial Pacific sediment core that spans the last similar to 255 ka. Contents of super(13)C in phytoplankton biomass were determined by analysis of C sub(37) alkadienones. These compounds are exclusive products of Prymnesiophyte algae which at present grow most abundantly at depths of 70-90 m in the central equatorial Pacific. A record of the isotopic composition of dissolved CO sub(2) was constructed from isotopic analyses of the planktonic foraminifera Neogloboquadrina dutertrei, which calcifies at 70-90 m in the same region. Values of epsilon sub(p), derived by comparison of the organic and inorganic delta values, were transformed to yield concentrations of dissolved CO sub(2) ( identical with c sub(e)) based on a new, site-specific calibration of the relationship between epsilon sub(p) and C sub(e). It is concluded that the observed record of epsilon sub(p) most probably reflects significant variations in Delta pCO sub(2), the ocean-atmosphere disequilibrium, which appears to have ranged from similar to 110 mu atm during glacial intervals (ocean > atmosphere) to similar to 60 mu atm during interglacials.
AN: 3753723
303 of 1521
TI: Selective preservation of chitin during the decay of shrimp
AU: Baas,-M.; Briggs,-D.E.G.; van-Heemst,-J.D.H.; Kear,-A.J.; de-Leeuw,-J.W.
AF: Div. Mar. Biogeochem., Netherlands Inst. Sea Res., P.O. Box 5G, 1790 AB Den Burg, Netherlands
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 5, pp. 945-951
LA: English
ER: M (Marine)
AB: The preservation potential of chitin in the marine environment is a matter of debate. To determine the relative survival of chitin and other organic components, the shrimp Crangon was decayed under different laboratory conditions. Solid state super(13)C NMR and Curie point pyrolysis-gas chromatography-high resolution mass spectrometry demonstrated that slightly transformed chitin represents the major component of the remaining biomass after only eight weeks. This selective preservation confirms that the resistance of chitin to decay may be a major factor in accounting for the extensive fossil record of arthropods lacking a biomineralized skeleton. It also suggests that chitin is likely to be an important contributor to the organic content of recent marine sediments. The pyrolysate of the preserved cuticle of fossil shrimps reveals a homologous series of alkanes and alkenes indicating a substitution of chitin by more resistant organic matter derived from other sources.
AN: 3753650
304 of 1521
TI: Glacial-interglacial paleoenvironments of the eastern Atlantic Ocean: The Biogeochemical Ocean Flux Study (BOFS) paleoceanography program
AU: Elderfield,-H.; Thomas,-E.
AF: Dep. Earth Sci., Univ. Cambridge, Cambridge, UK
SO: PALEOCEANOGRAPHY 1995 vol. 10, no. 3, pp. 509-511
NT: Special Section: The Biodegradation Ocean Flux Study.
LA: English
ER: M (Marine)
AB: The papers in this special section discuss many aspects of paleoenvironmental analysis performed using various proxies on cores collected in the northeastern and tropical eastern Atlantic during two cruises in the framework of the NERC Biogeochemical Ocean Flux Study Program (BOFS). Coring of the northern BOFS leg was carried out on Leg 3 of the 1989 BOFS program (RRS Discovery cruise 184). Forty-one cores were taken on a North-South transect at about 20 degree W, from the flanks of the Mid-Atlantic Ridge (47 degree N) to Gardar Drift (59 degree N), at water depths between 1150 and 4050 m. Of these, 15 cores were taken using a 3 m - long, large-diameter kastenlot corer. The southern leg coring was carried out on Leg C of the 1990 BOFS program (RRS Charles Darwin cruise 53 [Shimmield, 1990]). Forty-six cores, including 14 using the kastenlot corer, were taken along a transect at about 20 degree W, between 18 and 42 degree N, at depths between 3000 and 4900 m and focusing on an area off northwest Africa. Most papers in this section are concerned with different aspects of the differences in oceanic environments between glacial and interglacial periods, and especially between the last glacial and the Holocene, with much attention paid to changes in productivity and circulation patterns. All studies were conducted at high resolution (a few centimeter depth, corresponding to several hundred to a thousand or so years). The studies are unique in that many different proxies were collected on the sample sets of samples and at high time resolution.
AN: 3753546
305 of 1521
TI: The Key West campaign
AU: Tooma,-S.G.; Richardson,-M.D.
AF: Coast. Benthic, Bound. Layer Program, Nav. Res. Lab., Stennis Space Cent., MS, USA
SO: SEA-TECHNOL. 1995 vol. 36, no. 6, pp. 17-26
LA: English
ER: M (Marine)
AB: During February 1995, four research vessels (WFS Planet, R/Vs Seward Johnson, Pelican, and Seaward Explorer) and 115 scientists and technicians from five nations mounted a major scientific campaign in waters off the western Florida Keys. Experiments focused on the shallow-water, carbonate, sedimentary environments in the vicinity of the Marquesas Keys and the Dry Tortugas in recognition that naval operations have shifted focus to nearshore coastal operations that emphasize mine counter-measures (MCM).
AN: 3753533
306 of 1521
TI: Terminal Proterozoic reorganization of biogeochemical cycles
AU: Logan,-G.A.; Hayes,-J.M.; Hieshima,-G.B.; Summons,-R.E.
AF: Biogeochem. Lab., Dep. Geol. Sci., Indiana Univ., Bloomington, IN 47405-1403, USA
SO: NATURE 1995 vol. 376, no. 6535, pp. 53-56
LA: English
ER: M (Marine)
AB: The Proterozoic aeon (2,500-540 million years ago) saw episodic increases in atmospheric oxygen content, the evolution of multicellular life and, at its close, an enormous radiation of animal diversity. These profound biological and environmental changes must have been linked, but the underlying mechanisms have been obscure. Here we show that hydrocarbons extracted from Proterozoic sediments in several locations worldwide are derived mainly from bacteria or other heterotrophs rather than from photosynthetic organisms. Biodegradation of algal products in sedimenting matter was therefore unusually complete, indicating that organic material was extensively reworked as it sank slowly through the water column. We propose that a significant proportion of this reworking will have been mediated by sulphate-reducing bacteria, forming sulphide. The production of sulphide and consumption of oxygen near the ocean surface will have inhibited transport of O sub(2) to the deep ocean. We find that preservation of algal-lipid skeletons improves at the beginning of the Cambrian, reflecting the increase in transport by rapidly sinking faecal pellets. We suggest that this rapid removal of organic matter will have increased oxygenation of surface waters, leading to a descent of the O sub(2)-sulphide interface to the sea floor and to marked changes in the marine environment, ultimately contributing to the Cambrian radiation.
AN: 3753409
307 of 1521
TI: Pb super(2+) interactions with the marine phytoplankton Dunaliella tertiolecta
AU: Santana-Casiano,-J.M.; Gonzalez-Davila,-M.; Perez-Pena,-J.; Millero,-F.J.
AF: Dep. Quim., Fac. Cienc. Mar, Univ. Las Palmas de Gran Canaria, Las Palmas G.C., 35071, Spain
SO: MAR.-CHEM. 1995 vol. 48, no. 2, pp. 115-129
LA: English
ER: M (Marine)
AB: Metal ions become adsorbed to algal surface groups and complexed to organic material released by algae at all growth stages influencing their distribution in the seawater. In this study, the differential pulse anodic stripping voltammetry (DPASV) technique was used to evaluate the adsorption and the interaction between the exudates excreted by the marine algae Dunaliella tertiolecta and Pb super(2+). The adsorption process has been studied in seawater as a function of pH (2 to 8), temperature (5 to 45 degree C), salinity (5 to 36), biomass and the presence of a second metal, copper. The rate of adsorption was found to occur in two steps: first a relatively fast adsorption step (10 min) and second, a slow, diffusion-controlled uptake into the cells. A two-site model which considers the presence of two major functional groups, namely: high-affinity binding and low-affinity binding was used to fit the experimental data. The values for the stability constants of Pb super(2+) on these two groups were log *K super(S) sub(H,1) = 8.40 plus or minus 0.18 and log *K super(S) sub(H,2) = 7.25 plus or minus 0.31. The high-affinity constant is similar to the complexing capacity of the exudates (log *K super(2) sub(M) super(+) sub(e) = 8.40 plus or minus 0.05) produced by the alga showing that extracellular ligands play an important role in buffering the concentration of the free metal concentration. A decrease in the temperature and salinity result in lower adsorption of Pb super(2+) to the algae and a higher complexation of lead with the exudate. The presence of copper decreases the lead complexation to the algal surface by 70%.
AN: 3750403
308 of 1521
TI: Comparison of the linear Van den Berg/Ruzic transformation and a non-linear fit of the Langmuir isotherm applied to Cu speciation data in the estuarine environment
AU: Gerringa,-L.J.A.; Herman,-P.M.J.; Poortvliet,-T.C.W.
AF: Netherlands Inst. Ecol., Cent. Estuar. Coast. Ecol., Vierstr. 28, 4401 EA Yerseke, Netherlands
SO: MAR.-CHEM. 1995 vol. 48, no. 2, pp. 131-142
LA: English
ER: M (Marine); B (Brackish)
AB: Copper complexation measurements in estuarine organic-rich samples with differential pulse anodic stripping voltammetry (DPASV) and differential pulse cathodic stripping voltammetry (DPCSV) show a relatively large scatter in the data, due to a high organic matter content. Two methods for the estimation of the complexation parameters according to the Langmuir isotherm are compared: the linear transformation of Van den Berg/Ruzic and the non-linear method according to Wilkinson. For DPASV measurements in estuarine samples the values of the conditional stability constant (K super(1)), estimated with the linearization method are systematically lower than those estimated with the Wilkinson method. The Van den Berg/Ruzic linearization is more susceptible to outliers or data points that do not follow the model of the Langmuir isotherm. For DPCSV measurements, where the data followed the Langmuir isotherm more closely, this difference could not be demonstrated. The non-linear method is to be preferred because this method is more suited to the error structure of the data, which is of constant absolute magnitude. Moreover it offers the advantage that the standard error of the estimated parameters can be calculated consistently.
AN: 3750373
309 of 1521
TI: Simulation and prediction of anthropogenic lead perturbation in the Mediterranean Sea
AU: Tian,-Ru-Cheng; Ruiz-Pino,-D.
AF: Inst. Maurice Lamontagne, B378, C.P.1000, Mont-Joli, PQ G5H 3Z4, Canada
SO: SCI.-TOTAL-ENVIRON. 1995 vol. 164, no. 2, pp. 135-150
LA: English
ER: M (Marine)
AB: Simulations of Pb biogeochemical cycles were carried out based on a box model previously developed and tested by in-situ measurements. It has been demonstrated that the different evolutions of the fluxes determining the Pb budget lead to disequilibrium in Pb biogeochemical cycles in the Mediterranean Sea, particularly the anthropogenic perturbation governed by economical development and political regulations. Such a disequilibrium resulted in an increase in the concentration of lead between 1950 and 1976. Pb concentrations have decreased since 1976 in the Western Basin thanks to the application of limited Pb consumption regulations in the western countries. However Pb concentrations will increase again and the critical concentration for marine organisms will be reached by the middle of the next century if Pb consumption is not limited in the eastern countries. In relation to the exchange with the North Atlantic, the Mediterranean Sea acted as a sink for Pb before 1980, but since 1981, has become a source. Concerning the accumulation in the sediments, about half of the total external input was estimated to have been deposited between 1950 and 1992.
AN: 3750354
310 of 1521
TI: An improved head-space analysis method for methane in seawater
AU: Lammers,-S.; Suess,-E.
AF: GEOMAR - Forschungszent. Mar. Geowissenschaften, Wischhofstr. 1-3, D-24148 Kiel, FRG
SO: MAR.-CHEM. 1994 vol. 47, no. 2, pp. 115-125
LA: English
ER: M (Marine)
AB: A widely used degassing method for methane in seawater employing vacuum was tested and subsequently improved. It yielded 62 plus or minus 3.8% of the total dissolved methane, hence a reproducible correction factor was established. The method was then applied to measure CH sub(4) in the sea-air boundary layer and simultaneously in the overlying air along two transects in the eastern Equatorial Pacific off Peru in March of 1992. The results showed surprising small-scale reversals of the methane exchange between ocean and atmosphere in this region. Generally the ocean acted as a source of methane but also methane uptake by the ocean was found. This was mainly a consequence of high CH sub(4) concentrations in the air which deviated considerably from the long-term and large-scale average. If applied to the flux rate calculations, the observed variabilities indicate that both rate and direction of the methane flux through the air-sea interface vary considerably depending on the atmospheric CH sub(4) content. The implications are that even ocean areas with high concentrations of dissolved CH sub(4) can be considerably weaker sources than would be expected on the basis of 1.7 ppmv mean atmospheric methane content. Based on improved simultaneous analyses of both air and water samples, the ocean-atmosphere flux of methane would therefore be more dynamic than previously thought.
AN: 3750336
311 of 1521
TI: Isolation and characterization of methanesulfonic acid-degrading bacteria from the marine environment
AU: Thompson,-A.S.; Owens,-N.J.P.; Murrell,-J.C.*
AF: Dep. Biol. Sci., Univ. Warwick, Coventry CV4 7AL, UK
SO: APPL.-ENVIRON.-MICROBIOL. 1995 vol. 61, no. 6, pp. 2388-2393
LA: English
ER: M (Marine)
AB: Two methylotrophic bacterial strains, TR3 and PSCH4, capable of growth on methanesulfonic acid as the sole carbon source were isolated from the marine environment. Methanesulfonic acid metabolism in these strains was initiated by an inducible NADH-dependent monooxygenase, which cleaved methanesulfonic acid into formaldehyde and sulfite. The presence of hydroxypyruvate reductase and the absence of ribulose monophosphate-dependent hexulose monophosphate synthase indicated the presence of the serine pathway for formaldehyde assimilation. Cell suspensions of bacteria grown on methanesulfonic acid completely oxidized methanesulfonic acid to carbon dioxide and sulfite with a methanesulfonic acid/oxygen stoichiometry of 1.0:2.0. Oxygen electrode-substrate studies indicated the dissimilation of formaldehyde to formate and carbon dioxide for energy generation. Carbon dioxide was not fixed by ribulose bisphosphate carboxylase. It was shown that methanol is not an intermediate in methanesulfonic acid metabolism, although these strains grew on methanol and other one-carbon compounds, as well as a variety of heterotrophic carbon sources. These two novel marine facultative methylotrophs have the ability to mineralize methanesulfonic acid and may play a role in the cycling of global organic sulfur.
AN: 3749300
312 of 1521
TI: Role of SO sub(4) adsorption and desorption in the long-term S budget of a coniferous catchment on the Canadian Shield
AU: Houle,-D.; Carignan,-R.*
AF: Univ. Montreal, Dep. Sci. Biol., 90 Ave. Vincent-d'Indy, C.P. 6128, Succ. A Montreal, PQ H3C 3J7, Canada
SO: BIOGEOCHEMISTRY 1995 vol. 28, no. 3, pp. 161-182
LA: English
ER: F (Freshwater)
AB: The hypothesis that SO sub(4) desorption can explain apparent long term net SO sub(4)-S losses (5 kg/ha/yr on average) at the Lake Laflamme catchment from 1982 to 1991 is examined. Field observations show that SO sub(4) concentrations in the soil solution are strongly buffered during percolation through the Bf horizon. In the Bf horizon, SO sub(4) exchange reactions between the adsorbed and aqueous compartments are rapid (hours). Most ( approximately 60%) of the adsorbed SO sub(4) may be readily desorbed with deionized water. These observations and the presence of an important adsorbed SO sub(4)-S reservoir in the Bf horizon as compared with annual wet SO sub(4)-S deposition (7 kg/ha), suggest that on the short-term, adsorption and desorption reactions can control dissolved SO sub(4) concentration in the Bf horizon. To examine were SO sub(4) adsorption/desorption could explain long-term SO sub(4)-S losses by the catchment, an aggregated Langmuir isotherm for the Bf horizon was used to calculate the catchment's resilience to changing SO sub(4)-S loads. The results indicate that the soil should adjust rapidly (within 4 years) to changing SO sub(4)-S loads and that SO sub(4) desorption alone cannot explain long-term net SO sub(4)-S losses. Other possibilities, such as an underestimation of dry deposition or the weathering of S-bearing minerals also appear unlikely. Our results suggest a net release of SO sub(4)-S from the soil organic S reservoirs (1230 kg/ha) present in the catchment.
AN: 3749208
313 of 1521
TI: Geochemical consequences of the Chernobyl accident
AU: Kopeykin,-V.A.
AF: All-Russian Nonmetallic Min. Resour. Geol. Res. Inst., Kazan, Russia
SO: GEOCHEM.-INT.;GEOKHIMIYA 1994;1993 vol. 31, no. 5, pp. 134-137;no. 10
LA: English
ER: F (Freshwater)
AB: The Chernobyl disaster discharged a vast amount of radioactive material into the atmosphere, which was deposited near the station and far away. The power station is located on the bank of the Pripyat R., and the floodplain of the river is very marshy, with a high groundwater level near the station. A large area of pine forest died as a result of the irradiation. The first forecasts on fallout dissolution were meant to be reassuring, and no dissolution phenomena were expected in the immediate future. The result of this forecast had a bearing on the storage of radioactive wastes: the dead pines with the radioactive dust on them were felled in 1987 and buried in trenches cut in the sandy soil, without clay screening. This storage is without visible signs now, i.e., the stores are very difficult to locate. One of the areas for this storage to the west of Chernobyl lies on the first terrace of the Pripyat above the floodplain at levels of 111.7 to 113.4 m. The region is composed in the main of Quaternary fine-grained sands, often clayey. The groundwater table in this region is at depths from 0.5 to 1.6 m. The average annual water-table level fluctuation is 0.4 m.
AN: 3748506
314 of 1521
TI: Data management for JGOFS: Theory and design
AU: Flierl,-G.R.; Bishop,-J.K.B.; Glover,-D.M.; Paranjpe,-S.
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP,-FEBRUARY-18-21,-1992. J.-Churgin-comp. Commission-of-the-European-Communities,-Brussels-Belgium GREENBELT,-MD-USA GODDARD-SPACE-FLIGHT-CENT. 1992 pp. 229-250
LA: English
ER: M (Marine)
AB: We have constructed prototypes of the servers, methods, and constructed objects. We have much of the North Atlantic Bloom data entered into the system, along with various historical data sets and (separately) data from the SYNOP program. The process of documenting and training users will begin this year; assessment of the merits of the approach are still to come. However, we believe that, for on-going projects, on-line access to current data sets has many advantages. Likewise, the idea of building "extensible" data systems, analysis packages, and graphics packages should offer significant improvements in our abilities to share software.
AN: 3747017
315 of 1521
TI: Data management for community research projects: A JGOFS case study
AU: Lowry,-R.K.
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP,-FEBRUARY-18-21,-1992. J.-Churgin-comp. Commission-of-the-European-Communities,-Brussels-Belgium GREENBELT,-MD-USA GODDARD-SPACE-FLIGHT-CENT. 1992 pp. 251-274
LA: English
ER: M (Marine)
AB: Since the mid 1980s, much of the marine science research effort in the United Kingdom has been focused into large scale collaborative projects involving public sector laboratories and university departments, termed Community Research Projects. Two of these, the Biogeochemical Ocean Flux Study (BOFS) and the North Sea Project incorporated large scale data collection to underpin multidisciplinary modeling efforts. The challenge of providing project data sets to support the science was met by a small team within the British Oceanographic Data Centre (BODC) operating as a topical data centre. The role of the data centre was to both work up the data from the ship's sensors and to combine these data with sample measurements into online databases. The working up of the data was achieved by a unique symbiosis between data centre staff and project scientists. The project management, programming and data processing skills of the data centre were combined with the oceanographic experience of the project communities to develop a system which has produced quality controlled, calibrated data sets from 49 research cruises in 3.5 years of operation. The data centre resources required to achieve this were modest and far outweighed by the time liberated in the scientific community by the removal of the data processing burden.
AN: 3747016
316 of 1521
TI: Regulation of copper concentration in the oceanic nutricline by phytoplankton uptake and regeneration cycles
AU: Sunda,-W.G.; Huntsman,-S.A.
AF: Beaufort Lab., NMFS/NOAA, 101 Pivers Island Rd., Beaufort, NC 28516, USA
SO: LIMNOL.-OCEANOGR. 1995 vol. 40, no. 1, pp. 132-137
LA: English
ER: M (Marine)
AB: Similar sigmoidal relationships were observed between cellular Cu:C ratios and free cupric ion concentration for the neritic alga Thalassiosira pseudonana and two oceanic species (Thalassiosira oceanica and Emiliania huxleyi) grown in trace metal ion buffered media. Only 5-9-fold variations in cell Cu:C were observed for these species over the [Cu super(2+)] range 3 x 10 super(-15) to 3 x 10 super(-12) M, with increasing cell copper vs. [Cu super(2+)] slopes above and below this range. At the mean [Cu super(2+)] for the euphotic zone of the North Pacific (10 super(-13.2) M), cell Cu:C ratios for the three species were 4.4, 4.4, and 3.8 mu mol/mol, similar to values for plankton taken from North Pacific waters. These values also match the mean Cu:C ratio of 4.1 mu mol/mol determined from slopes of linear relationships between Cu and PO sub(4) in the nutricline of the central North Pacific and the "Redfield" C:PO sub(4) ratio in plankton of 106:1. This agreement provides strong evidence that copper concentrations in remote oceanic nutriclines are regulated by phytoplankton uptake and regeneration processes.
AN: 3745817
317 of 1521
TI: What determines sedimentary C/S ratios?
AU: Morse,-J.W.; Berner,-R.A.
AF: Dep. Oceanogr., Texas A&M Univ., College Station, TX 77843, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 6, pp. 1073-1077
LA: English
ER: M (Marine)
AB: The weight ratio of organic carbon to pyrite sulfur (C/S) has been observed to fall within a relatively narrow range (2.8 plus or minus 0.8) in most fine-grained normal marine siliciclastic sediments. Although an increasing number of exceptions to this typical C/S ratio have been observed, it is nonetheless remarkable that so many modern and ancient marine sediments fall within a range of about a factor of two in C/S ratios. Here we demonstrate that this demands that the three major factors that control this ratio must be quite closely coupled to each other. These factors are (1) the fraction of organic carbon that is metabolized, (2) the fraction of metabolized organic carbon that is metabolized via sulfate reduction, and (3) the fraction of reduced sulfide that is not oxidized and is buried in pyrite. A simple model is presented that has utility in demonstrating the relationships among these parameters that are necessary to produce typical normal marine sediments C/S ratios.
AN: 3745506
318 of 1521
TI: Long-term hydrologic and biogeochemical responses of a soft water seepage lake in north central Wisconsin
AU: Wentz,-D.A.; Rose,-W.J.; Webster,-K.E.
AF: U.S. Geol. Surv., Portland, OR, USA
SO: WATER-RESOUR.-RES. 1995 vol. 31, no. 1, pp. 199-212
LA: English
ER: F (Freshwater)
AN: 3744700
319 of 1521
TI: Carbon flux and recycling associated with zooplanktonic fecal pellets on the shelf of the Middle Atlantic Bight
AU: Lane,-P.V.Z.; Smith,-S.L.; Urban,-J.L.; Biscaye,-P.E.
AF: Mar. Biol. and Fish. Div., Rosenstiel Sch. Mar. and Atmos. Sci., 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 213, pp. 437-457
LA: English
ER: M (Marine)
AB: Sediment traps were deployed for 5 days during March 1988, at 20 and 33 m in 42 m of water over the continental shelf off Norfolk, Virginia (SEEP-II study area). During the sediment trap deployment, a time-series study determined the community and age-structure of copepods as well as the standing stocks, production rates and settling velocities of fecal pellets. Fecal pellets comprised less than 1% of the total particulate carbon collected in the sediment traps and ca 0.3% of particulate carbon found in the water column. Mean fecal pellet production by adult copepods feeding in natural seawater ranged from 1 to 2 pellets animal super(-1) day super(-1), equalling approximately 0.1-0.3 mu g C day super(-1). Average fecal pellet volume ranged from 4 x 10 super(5) mu m super(3) for pellets produced by Centropages typicus females to 14 x 10 super(5) mu m super(3), for pellets produced by Calanus finmarchicus females. The pellets produced by C. finmarchicus were important in the downward vertical transport of phytoplankton carbon, while pellets produced by smaller copepods were primarily recycled in the water column. Lateral advective processes altered the species composition of zooplankton at our study site. The onshore and offshore movement of different zooplankton communities with varying size-structure could have a substantial impact on the magnitude of vertical carbon transport on continental shelves.
AN: 3743519
320 of 1521
TI: super(210)Pb balance and implications for particle transport on the continental shelf, U.S. Middle Atlantic Bight
AU: Bacon,-M.P.; Belastock,-R.A.; Bothner,-M.H.
AF: Woods Hole Oceanogr. Insti., Woods Hole, MA 02503, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 2/3, pp. 511-535
LA: English
ER: M (Marine)
AB: Supply of super(210)Pb to the continental shelf off the northeastern United States is dominated by the deposition from the atmosphere, the rate of which is reliably known from previously published work. Excess super(210)Pb inventories in the shelf sediments show accumulations that are nearly in balance with the supply, even in areas of relict sands where it is believed that no net accumulation of sediment presently occurs. The super(210)Pb distributions in shelf and slope water indicate that the two-way fluid exchange at the shelf-slope front and the net transport in the alongshore flow make comparatively small contributions to the shelf super(210)Pb budget. The near balance between supply and decay of super(210)Pb on the shelf implies a limit to the particle export flux. It is concluded that the export of particulate organic carbon does not exceed 60 g m super(-2) y super(-1) ( similar to 25% of primary production) and is probably lower. The hypothesis is advanced that fine particulate matter introduced to the continental shelf is detained in its transit of the shelf because of bioturbational trapping in the sediment due to benthic animals. Distributions of super(210)Pb in suspended particulate matter and in the fine fraction of shelf sediments suggest that the average fine particle must undergo several cycles of deposition-bioturbation-resuspension-redeposition and requires a number of decades for its transit and ultimate export from the shelf. Thus, only the most refractory organic matter is likely to be exported.
AN: 3742857
321 of 1521
TI: Microbial carbon utilization on the continental shelf and slope during the SEEP-II experiment
AU: Kemp,-P.F.
AF: Brookhaven Natl. Lab., Oceanogr. and Atmos. Sci. Div., Upton, NY 11973, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 2/3, pp. 563-581
LA: English
ER: M (Marine)
AB: Microbial processes were measured as part of the Shelf Edge Exchange Processes II (SEEP-II) experiment, which was designed to re-examine the hypothesis that a substantial fraction of primary production on the continental shelf is exported to the slope and deeper ocean. Bacterial-mediated carbon remineralization was defined as the sum of measured bacterial production plus estimated bacterial respiration. Carbon remineralization, summed over the water column plus surficial sediment, was 90-180 mg C m super(-2)/day on the shelf and 270-540 mg C m super(-2)/day on the slope. These are equivalent to 12-24% and 33-66% of daily primary production on the shelf and slope, respectively. The majority of bacterial activity occurs in sediments on the shelf, but on the slope it is attributable to bacteria in the deep water column. Concurrent sediment trap data indicate that material sinking from surface waters overlying the slope can supply only a small fraction of carbon remineralized by bacteria in the intermediate water column. Bacterial production in slope water and sediments may be subsidized by export from the shelf. Because of the greater width of the shelf than slope, this additional demand on shelf carbon would represent only 7.5-15% of shelf primary production. Mean specific growth rates of sediment bacteria were very uniform at depths between 40 and 2000 m. This suggests bacterial growth may be limited by some common factor, although environmental factors known to affect growth rates generally vary with depth. DNA synthesis rates (measured by thymidine incorporation) were comparable to rates observed for marine bacteria in nutrient-replete culture. The implication is that sediment bacteria were not limited by nutrient availability. If true, water column and sediment bacterial production are likely to be controlled by very different processes: water-column bacteria by both nutrient limitation and grazing, and sediment bacteria by grazing alone.
AN: 3742855
322 of 1521
TI: Particle export at Cape Hatteras
AU: Walsh,-J.J.
AF: Dep. Mar. Sci., Univ. South Florida, St. Petersburg, FL 33701, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 2/3, pp. 603-628
LA: English
ER: M (Marine)
AB: A simple model of shelf, slope and basin waters near Cape Hatteras, North Carolina is used to estimate the sources and sinks of organic carbon within the Gulf Stream System. The analysis employs water transport estimates, nutrient data, satellite imagery, surficial sediment records and particle distributions caught by bottle, camera and sediment trap to compute vertical and lateral fluxes of particulate carbon. Particle export from the SAB and MAB shelf ecosystems may constitute 62-82% of the source of the carbon flux within the Gulf Stream near 75 degree W, after settling at 100 m/day, with an oxidation loss of 4%/day, to a nominal mid-depth of 1000 m on the slope. As a result of light limitation, denitrification and DON solubilization, partial utilization of onwelled nitrate from the Gulf Stream System by coastal phytoplankton suggests that the time-averaged f ratio may be as small as 0.12 for the ratio of the "new" portion of primary production to the total. After burial loss, the export of particulate matter from the shelves then represents at most 11% of the total carbon fixation of coastal waters. If the shelf export of DON and unutilized NO sub(3) is consumed within adjacent slope waters, however, the f ratio and the percentage of particle export from the carbon fixation of shelf-affected waters might increase to 0.25 and 24%.
AN: 3742854
323 of 1521
TI: The lateral flux of biogenic particles from the eastern North American continental margin to the North Atlantic Ocean
AU: Falkowski,-P.G.; Biscaye,-P.E.; Sancetta,-C.
AF: Oceanogr. and Atmos. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 2/3, pp. 583-601
LA: English
ER: M (Marine)
AB: Sediment trap samples from two field programs on the continental margin of the northeast coast of the United States, which constituted the Shelf Edge Exchange Program (SEEP), were analyzed for phytoplankton taxonomic composition and the fluxes of organic carbon, nitrogen and opaline silica. The traps, with a rotating carousel collection system, were located on taut-wire moorings between 150 and 2700 m below the surface and extended from the 500 m isobath on the upper continental shelf to the 2750 m isobath at the edge of the abyssal plain of the western North Atlantic Ocean. The temporal and spatial distributions of phytoplankton in the azide-poisoned trap samples revealed a general increase of intact cells with depth, which is consistent with lateral transport from the margins to the ocean interior. Taxonomic analysis of the phytoplankton indicated that >90% of the intact cells (containing identifiable intracellular structures) consisted of diatoms. The distribution of the species further supports the lateral transport origin of the particles, and indicates that the particulate materials are delivered to the ocean interior primarily in pulses of rapidly sinking aggregates. However, quantitative analysis suggests that intact phytoplankton contribute only 0.8 plus or minus 0.7% (mean and S.D.) and 0.9 plus or minus 0.7% of the total particulate carbon and nitrogen fluxes, respectively. Using silica-to-carbon ratios to budget the remaining trap organic carbon fluxes, it would appear that between 17 and 100% of the sedimenting particles were originally diatomaceous, but that the organic carbon became solubilized and/or oxidized in the water column during descent. A simple two-dimensional model was developed to quantify the contribution of the flux of particulate organic carbon to the interior of the North Atlantic Ocean. The results suggest that north of Cape Hatteras, the mean lateral flux of particulate organic carbon sinking through the upper 500 m of the water column into the western edge of the basin is 4.8 x 10 super(12) g C/y, which is about 6% of the primary production on the shelf. This flux represents the lateral export of carbon from the continental margin to the interior of the North Atlantic Ocean. Based on estimates of vertical export production for the basin of about 4.2 x 10 super(14) g C/y, we estimate that the export of carbon from the western margin, north of Cape Hatteras, represents about 1% of the new production of the entire basin. This export is a significant source of energy which fuels the high benthic respiration on the continental slope.
AN: 3742853
324 of 1521
TI: Deep-sea floor respiration as an indication of lateral input of biogenic detritus from continental margins
AU: Rowe,-G.T.; Boland,-G.S.; Phoel,-W.C.; Anderson,-R.F.; Biscaye,-P.E.
AF: Dep. Oceanogr., Texas A&M Univ., College Station, TX 77843, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 2/3, pp. 657-668
LA: English
ER: M (Marine)
AB: Sediment oxygen demand, estimated using in situ chambers on a benthic lander, incubations of recovered cores and values previously published by others, has been used as a measurement of the flux of organic matter to the sea floor from the continental shelf and slope out to the abyssal plain in the northwest Atlantic. Rates were highest on the continental margin, and declined precipitously offshore. On the middle continental slope, rates were almost as high as those on the continental shelf, supporting the idea that mid-slope depths at ca 1000 m depth are a "depocenter" for particulate organic debris. The sediment oxygen demand, in terms of carbon equivalents (mg C m super(-2)/day), was generally lower than near-bottom POC fluxes measured in sediment traps. This imbalance is attributed to a combination of burial, anaerobic metabolism not reflected in oxygen demand, and continued lateral export along or offshore near the bottom. The exception to this pattern was the mid-slope depocenter, where the measured POC input was slightly less than the total organic carbon demand estimated with the lander. A comparison with other work suggests that at most depths on the continental margin the sediment oxygen demand is higher off the west coast of the U.S.A. than off the east coast. The upper to middle continental slope (500-1500 m depth) is the only zone over which sediment oxygen demand is higher on the east coast, but this can be attributed to the physiological limitations of low ambient oxygen concentration on heterotrophic metabolism in the pronounced oxygen minimum on the west coast.
AN: 3742851
325 of 1521
TI: The shelf edge exchange processes experiment, SEEP-II: An introduction to hypotheses, results and conclusions
AU: Biscaye,-P.E.; Flagg,-C.N.; Falkowski,-P.G.
AF: Lamont-Doherty Earth Obs. Columbia Univ., Palisades, NY 10964, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 2/3, pp. 231-252
LA: English
ER: M (Marine)
AB: The SEEP (Shelf Edge Exchange Processes)-II experiment was the second of two that took place in the Middle Atlantic Bight (MAB) of the eastern U.S. continental shelf and slope. The experiment included an array of 10 multi-instrumented moorings deployed for 15 months and 10 oceanographic cruises, all designed to address the problem of the fate of continental shelf particulate matter in general, and organic carbon in particular. This paper provides the setting and background for the SEEP Program, the SEEP-II experiment and an introduction to the 18 papers constituting the subject of this special volume. Because those papers lack one of a general nature on the physical oceanographic setting of the experiment, that aspect is treated in somewhat more detail here. The results of the experiment overwhelmingly show that the working hypothesis on which the SEEP Program was undertaken and sponsored by the Department of Energy is not valid. That is, there is not an export to the adjacent slope and open ocean of a large proportion of the particulate matter introduced to and biologically generated in the waters of the continental shelf; most of the biogenic particulate matter is recycled by consumption (bacterial and otherwise) and oxidation on the shelf, and only a small proportion (of order << 5%) is exported to the adjacent slope. The small amount that is exported appears to be deposited preferentially in the sediments of an area of the slope centered at about 1000 m, and the export and sedimentation to that depocenter appears to increase from the northern to the southern MAB.
AN: 3742849
326 of 1521
TI: Modelling physical-biological coupling in the ocean: The U.S. GLOBEC Program
AU: Eckman,-J.E.
AF: Skidaway Inst. Oceanogr., 10 Ocean Science Circle, Savannah, GA 31411, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 1, pp. 1-5
LA: English
ER: M (Marine)
AB: Evidence continues to accumulate that the Earth's environment is changing. The change is not localized, but extends from the tropics to the poles, and is apparent in the atmosphere, on land and in the ocean. Some of these shifts are thought to be anthropogenic (e.g. ozone depletion at high latitudes, increasing concentrations of "greenhouse" gases), but paleoclimatic records also suggest that the Earth has experienced significant climatic changes in the past. We do not known whether many of these changes occur cyclically, stochastically, episodically or represent long-term trends. We have little knowledge about time scales characterizing most of these changes. Some clearly are relatively short-lived (e.g. El Nino/Southern Oscillation events), while others may operate over long time scales (e.g. incorporation of carbon into the deep sea). Researchers who study these changes are engaged in attempts to verify the existence, magnitude and causes of these shifts. One of the great and important challenges facing scientists is using the discoveries of these researchers to predict the direction and magnitude of the responses of the Earth's biota to current climatic shifts. The U.S. GLOBEC (GLOBal Ocean ECosystems Dynamics) program is a research initiative organized by the oceanographic and fisheries communities, and supported principally by the National Science Foundation (NSF) and National Oceanic and Atmospheric Administration (NOAA), that aims to understand how changes in the global environment are expected to affect the abundances and production of animals in the sea.
AN: 3742544
327 of 1521
TI: Studies on regeneration rate of nitrogen in decomposition of plankton in lake
AU: Zhuang,-Yuanyi; Dai,-Shugui; Zhang,-Mingshun
AF: Dep. Environ. Sci., Nankai Univ., Tianjin 300071, People's Rep. China
SO: CHINA-ENVIRON.-SCI.-ZHONGGUO-HUANJING 1993 vol. 13, no. 2, pp. 81-84
LA: Chinese
ER: F (Freshwater)
AB: Informations about the nitrogen regeneration in decomposition of plankton sampled from Dianchi Lake and the factors influencing the decomposition are presented in this paper. The results of the simulation test show that the main regeneration products in decomposition of plankton are NH sub(4) super(+)-N and NO sub(3) super(-) + NO sub(2) super(-) - N in water, NH sub(4) super(+)-N and organic N in sediment. The decomposition rates constant in water in dark are 0.07/d and 0.12/d at 20 degree C and 30 degree C respectively. The decomposition in light can stimulate the growth of algae in water.
AN: 3742533
328 of 1521
TI: Trace metal distribution, partition and fluxes in the Seine Estuary (France) in low discharge regime
AU: Chiffoleau,-J.-F.; Cossa,-D.; Auger,-D.; Truquet,-I.
AF: IFREMER, Cent. Nantes, BP 1049, 44037 Nantes Cedex 01, France
SO: MAR.-CHEM. 1994 vol. 47, no. 2, pp. 145-158
LA: English
ER: M (Marine); B (Brackish)
AB: Samples collected in surface waters of the Seine estuary (France) during a low discharge period were analyzed for dissolved and particulate trace metals (Cd, Co, Cu, Mn, Ni, Pb and Zn). The studies showed that these trace elements are reactive in the estuary: an addition to the dissolved phase is observed for Cd, Co, Cu, Mn, Ni and Zn and a removal for Pb. Cd, Cu, Ni and Zn are released from seaward fluxing riverine particles or estuarine sediments directly in the water column, while the dissolved Co-salinity distribution, similar to Mn distribution suggests a preliminary release in the sediment pore water. Rapid adsorption onto the suspended load plays a major role in Pb removal from the dissolved phase. Partition coefficients for the dissolved and particulate phase (K sub(D)) decrease in the order: Pb > Co > Cu, Zn > Ni > Cd, i.e. a sequence similar to those reported from others European areas. Gross riverine inputs to the estuary and net efflux of dissolved trace metals to the English Channel are estimated. Values show that the Seine river and its estuary constitute a significant source of trace metals for the North Sea.
AN: 3742324
329 of 1521
TI: Development of a gold amalgam voltammetric microelectrode for the determination of dissolved Fe, Mn, O sub(2), and S(-II) in porewaters of marine and freshwater sediments
AU: Brendel,-P.J.; Luther,-G.W.,III
AF: Dep. Chem. Biochem. Coll., Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: ENVIRON.-SCI.-TECHNOL. 1995 vol. 29, no. 3, pp. 751-761
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: A solid-state voltammetric gold amalgam microelectrode has been developed for the measurement of dissolved O sub(2), S(-II), Fe, and Mn in the porewaters of marine sediments. This electrode can provide more information at (sub)millimeter depth resolution on all of the major redox species found in the environment than membrane microelectrodes which usually can measure only one of these species per electrode. We describe the construction, standardization, analytical validation, and application of a microelectrode to marine sediments. The use of the microelectrode takes advantage of the fast scan voltammetric methods for simultaneous measurement of all redox species during one potential scan. Electrochemical conditioning of the solid-state microelectrode between voltage scans while deployed in waters and sediments allows for repeated use of the electrode. Finally, we demonstrate depth profiles at millimeter resolution for the redox species in a Delaware salt marsh. The profiles observed are consistent with the known biogeochemical cycling of the target redox species. In addition, we provide evidence for H sub(2)O sub(2), iron(II) sulfide complexes, and iron(III) colloids or organic complexes in porewaters.
AN: 3742172
330 of 1521
TI: The remineralization of organic carbon on the North Carolina continental slope
AU: Blair,-N.E.; Plaia,-G.R.; Boehme,-S.E.; DeMaster,-D.J.; Levin,-L.A.
AF: Dep. Mar., Earth and Atmos. Sci., North Carolina State Univ., Raleigh, NC 27695-8208, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 4-6, pp. 755-766
LA: English
ER: M (Marine)
AB: The sources and fates of metabolizable organic carbon were examined at three sites on the North Carolina slope positioned offshore of Cape Fear, Cape Lookout and Cape Hatteras. The super(13)C/ super(12)C compositions ( delta super(13)C) of the solid phase organic matter, and the dissolved inorganic carbon ( capital sigma CO sub(2)) produced during its oxidation, suggested that the labile fraction was predominantly marine in origin. The capital sigma CO sub(2) concentration gradient across the sediment-water interface, and by inference the capital sigma CO sub(2) flux and production rate, increased northward from Cape Fear to Cape Hatteras. Methane distributions and capital sigma CO sub(2) delta super(13)C values suggest that the rate of anaerobic diagenesis increased northward as well. The differences in sedimentary biogeochemistry are most likely driven by an along-slope gradient of reactive organic carbon flux to the seabed. This trend in reactive organic carbon flux correlates well with macrofaunal densities previously observed at the three sites. Proximity to the shelf and the transport of particulate material by surface boundary currents may control the deposition of metabolizable material on the Carolina slope. Evidence for methanogenesis was found only on the Cape Hatteras slope. The methane, which was produced at a depth of approximately 1 m in the seabed, was consumed nearly quantitatively in the biologically mixed layer as it diffused upward. Irrigation of the sediments by infauna may have provided the necessary oxidant for the consumption of the methane.
AN: 3740443
331 of 1521
TI: Iron chemistry in seawater and its relationship to phytoplankton: A workshop report
AU: Wells,-M.L.; Price,-N.M.; Bruland,-K.W.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
SO: MAR.-CHEM. 1995 vol. 48, no. 2, pp. 157-182
LA: English
ER: M (Marine)
AB: The perceptions of ocean chemists and algal physiologists have shifted enormously over the past two decades, from attempts to correlate metal uptake by phytoplankton with bulk measurements of total "dissolved" metals, to recognizing that metal speciation is the critical factor. This evolution in thinking began with well-defined, metal buffered laboratory culture experiments and the principles learned there have appeared to work well for predicting the biological effects of various metals (e.g. Cu, Zn, and Mn) in natural systems; until iron. It became apparent during the workshop discussions that two main factors contribute to the vexing difficulty in characterizing the relationship between iron chemistry and phytoplankton dynamics. First, the marine chemistry of iron is more complex and less explored than many other bioactive metals. The second complicating factor is the diversity of iron uptake strategies likely employed by phytoplankton. Though a central goal of the workshop was to better define iron availability to help develop analytical tools for quantifying this bioavailable fraction in seawater, this task is not possible given the foundation of our present knowledge. Quantification of iron "availability" in natural waters awaits better characterization of the marine chemistry of iron in conjunction with exploration of the uptake strategies used by different members of the algal community. What emerged then from this workshop was a shift in the paradigm of iron biogeochemistry in seawater, from one in which iron/phytoplankton interactions behave similarly as for other bioactive metals to one in which iron stands as truly unique.
AN: 3740329
332 of 1521
TI: Effects of man-made and natural sources on the heavy-metal patterns in bottom sediments in the Gulf of Peter the Great, Sea of Japan
AU: Anikiyev,-V.V.; Perepelitsa,-S.A.; Shumilin,-Y.N.
AF: Pac. Oceanol. Inst., Far East Div., Russian Acad. Sci., Vladivostok, Russia
SO: GEOCHEM.-INT.;GEOKHIMIYA 1994;1993 vol. 31, no. 4, pp. 73-85;no. 9
LA: English
ER: M (Marine)
AB: Flame atomic-absorption spectrophotometry has been used to study the distribution of Zn, Pb, Ag, Cd, Cu, Ni, Co, and Mn in bottom sediments in the Gulf of Peter the Great (Sea of Japan). Zones of impact on the sediment composition are identified due to the following sources: a) dumping in Gornostay Bay, b) the cities of Vladivostok and Bol'shoy Kamen', and c) the Razdol'naya River. The Zn, Pb, Cd, Cu, and Ag contents in bottom sediments in regions affected by human action are controlled by the positions and outputs of the pollution sources. The distribution of the lithophile elements (Mn, Ni, and Cu) in the bottom sediments of the gulf have been governed mainly by natural processes: chemical weathering of bedrock, denudation above the principal erosion base, and coastal abrasion.
AN: 3740128
333 of 1521
TI: Input, accumulation and cycling of materials on the continental slope off Cape Hatteras: An introduction
AU: Blake,-J.A.; Diaz,-R.J.
AF: Sci. Appl. Int. Corp., 89 Water St., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-II-TOP.-STUD.-OCEANOGR. 1994 vol. 41, no. 4-6, pp. 707-710
LA: English
ER: M (Marine)
AB: The studies reported in this special issue of Deep-Sea Research are largely derived from data collected as part of programs supported by the U.S. Department of the Interior, Minerals Management Service (MMS) in response to concerns about the effect of oil and gas exploration on the largely unknown continental slope environment. Results of the MMS U.S. South Atlantic continental slope and rise program conducted off the Carolinas from Cape Hatteras to off Charleston in depths ranging from 600-3500 m identified the importance of the slope off Cape Hatteras in cycling of materials from the shelf to the deep sea. Other more detailed investigations followed which filled numerous gaps in our knowledge of the role played by such special regions of the continental slope in the global cycling of carbon and other materials.
AN: 3739786
334 of 1521
TI: Solute fluxes and sulfur cycling in forested catchments in SW Germany as influenced by experimental (NH sub(4)) sub(2)SO sub(4) treatments
AU: Feger,-K.H.
AF: Inst. Soil Sci. and Forest Nutr., Albert-Ludwig-Univ., Bertoldstr. 17, D-79085 Freiburg i.Br., FRG
CO: BIOGEOMON, The Symposium on Ecosystem Behaviour: Evaluation of Integrated Monitoring in Small Catchments, Prague (Czech Rep.), 18-20 Sep 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1995 vol. 79, no. 1-4, pp. 109-130
LA: English
ER: F (Freshwater)
AB: Results are presented from the research project ARINUS which investigates biogeochemical cycling in Norway spruce (Picea abies KARST.) ecosystems in the Black Forest (SW Germany) and effects of experimental (NH sub(4)) sub(2)SO sub(4) additions. The interaction of the terrestrial and aquatic system is assessed using an integrated approach which combines flux measurements in representative plots on the stand level with input-output budgets of small catchments. The approach, field installations and experimental manipulations are described. Results from element flux measurements in the untreated systems are presented and processes controlling N and S transformations are discussed for two catchments representing contrasting site conditions. Even though the S budget is negative for both systems there is a distinct difference in the relation between organic vs. inorganic S fractions in the soil. Sulfate mineralization and desorption, respectively are discussed as controlling processes. Sulfate retention is not only a function of soil properties, but also of water fluxes and pathways. The uptake of added SO sub(4) super(2-) was highly controlled by the counter-cation. Microbial N retention in the soil was highly influenced by the site management history. The extent of streamwater acidification was highly dependent on the transformations and mobility of N and S in the soils which in turn controlled cation leaching and alkalinity.
AN: 3736396
335 of 1521
TI: Ion mass budgets for small forested catchments in Finland
AU: Forsius,-M.; Kleemola,-S.; Starr,-M.; Ruoho-Airola,-T.
AF: Water and Environ. Res. Inst., P.O. Box 250, FIN-00101 Helsinki, Finland
CO: BIOGEOMON, The Symposium on Ecosystem Behaviour: Evaluation of Integrated Monitoring in Small Catchments, Prague (Czech Rep.), 18-20 Sep 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1995 vol. 79, no. 1-4, pp. 19-38
LA: English
ER: F (Freshwater)
AB: Ion mass and H super(+) budgets were calculated for three pristine forested catchments using bulk deposition, throughfall and runoff data. The catchments have different soil and forest type characteristics. A forest canopy filtering factor for each catchment was estimated for base cations, H super(+), Cl super(-) and SO sub(4) super(2-) by taking into account the specific filtering abilities of different stands based on the throughfall quality and the distribution of forest types. Output fluxes from the catchments were calculated from the quality and quantity of the runoff water. Deposition, weathering, ion exchange, retention and biological accumulation processes were taken into account to calculate catchment H super(+) budgets, and the ratio between external (anthropogenic) and internal H super(+) sources. In general, output exceeded input for Na super(+), K super(+), Ca super(2+), Mg super(2+), HCO sub(3) super(-) (if present) and A super(-) (organic anions), whereas retention was observed in the case of H super(+), NH sub(4) super(-), NO sub(3) super(-) and SO sub(4) super(2-). The range in the annual input of H super(+) was 22.8-26.3 meq m super(-2) yr super(-1), and in the annual output, 0.3-3.9 meq m super(-2) yr super(-1). Compared with some forested sites located in high acid deposition areas in southern Scandinavia, Scotland and Canada, the catchments receive rather moderate loads of acidic deposition. The consumption of H super(+) was dominated by base cation exchange plus weathering reactions (41-79%), and by the retention of SO sub(4) super(2-) (17-49%). The maximum net retention of SO sub(4) super(2-) was 87% in the Hietajaervi 2 catchment, having the highest proportion of peatlands. Nitrogen transformations played a rather minor role in the H super(+) budgets. The ratio between external and internal H super(+) sources (excluding net base cation uptake by forests) varied between 0.74 and 2.62, depending on catchment characteristics and acidic deposition loads. The impact of the acidic deposition was most evident for the southern Valkeakotinen catchment, where the anthropogenic acidification has been documented also by palaeolimnological methods.
AN: 3736393
336 of 1521
TI: Sulfur isotope dynamics in a high-elevation catchment, West Glacier Lake, Wyoming
AU: Finley,-J.B.; Drever,-J.I.; Turk,-J.T.
AF: Dep. Geol., Miami Univ., Oxford, OH 45056, USA
CO: BIOGEOMON, The Symposium on Ecosystem Behaviour: Evaluation of Integrated Monitoring in Small Catchments, Prague (Czech Rep.), 18-20 Sep 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1995 vol. 79, no. 1-4, pp. 227-241
LA: English
ER: F (Freshwater)
AB: Stable isotopes of S are used in conjunction with dissolved SO sub(4) super(2-) concentrations to evaluate the utility of delta super(34)S ratios in tracing contributions of bedrock-derived S to SO sub(4) super(2-) in runoff. Water samples were collected over the annual hydrograph from two tributaries in the West Glacier Lake, Wyoming, catchment. Concentrations of SO sub(4) super(2-) ranged from 12.6 to 43.0 mu eq L super(-1); delta super(34)S ratios ranged from -1.8 ppt to +4.9 ppt. The delta super(34)S value of atmospherically derived SO sub(4) super(2-) is about +5.6 ppt; four samples of pyrite from the bedrock had delta super(34)S ratios that ranged from +0.7 to +4.1 ppt. Concentrations of SO sub(4) super(2-) were inversely related to delta super(34) and discharge. The data for the tributary with the higher SO sub(4) super(2-) concentrations were reasonably consistent with mixing between atmospheric S and S from a bedrock source with a delta super(34)S ratio of about -4.5 ppt. The difference from the measured bedrock values presumably indicates that S isotopes in the bedrock pyrite are heterogeneously distributed. The data from the tributary with lower SO sub(4) super(2-) concentrations did not follow a two-component mixing line. Deviation from a two-component mixing line is most likely caused by preferential elution of SO sub(4) super(2-) from the snowpack during the early stages of snowmelt, although microbially mediated fractionation of S isotopes in the soil zone also may cause the deviation from the mixing line. Sulfur isotopes are useful in identifying whether or not there is a substantial contribution of bedrock S to runoff, but quantifying that contribution is problematic.
AN: 3736376
337 of 1521
TI: Modeling excess sulfur deposition on wetland soils using stable sulfur isotopes
AU: Morgan,-M.D.
AF: Dep. Biol., Div. Pinelands Res., Rutgers Univ., Camden, NJ 08102, USA
CO: BIOGEOMON, The Symposium on Ecosystem Behaviour: Evaluation of Integrated Monitoring in Small Catchments, Prague (Czech Rep.), 18-20 Sep 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1995 vol. 79, no. 1-4, pp. 299-307
LA: English
ER: F (Freshwater)
AB: Freshwater wetlands exposed to excess S deposition can potentially store significant amounts of reduced S in soils by dissimilatory sulfate reduction. If this storage is permanent, the harmful environmental effects of S deposition and the accompanying acidity are reduced, particularly on surface waters into which wetlands drain. Total non-sulfate S in freshwater peat is divided into three fractions: reduced inorganic S, ester sulfate and carbon-bonded sulfur (CBS). Each fraction is further divided based on its origin: assimilatory via plant and microbial uptake, and dissimilatory via microbial reduction. The CBS fraction dominates in peat, so the amount of dissimilatory CBS in the soil is a direct measure of the beneficial effect of storage of reduced S. Unfortunately, there is no way to directly measure dissimilatory CBS. A model is developed which, with three assumptions, provides a method to calculate dissimilatory CBS using S pool size and stable isotope measurements. Application of the model to a wetland in the New Jersey Pinelands, U.S.A., shows that large amounts of reduced dissimilatory S are stored in the soil. As a consequence, the impact of S deposition and acidity on the surface water environment is significantly reduced.
AN: 3736375
338 of 1521
TI: Effects of the physicochemical properties of bioinorganic complexes on the content of elements in marine organisms
AU: Karyakin,-A.V.; Sayenko,-G.N.; Zorina,-L.G.
AF: Vernadskiy Inst. Geochem. and Anal. Chem., Russian Acad. Sci., Inst. Oceanol., Moscow, Russia
SO: GEOCHEM.-INT.;GEOKHIMIYA 1994;1993 vol. 31, no. 4, pp. 107-111;no. 9
LA: English
ER: M (Marine)
AN: 3735531
339 of 1521
TI: Evaluation of the role of submerged plant beds in the metal budget of a fluvial lake
AU: St-Cyr,-L.; Campbell,-P.G.C.; Guertin,-K.
AF: INRS-Eau, Univ. Quebec, C.P. 7500, Sainte-Foy, PQ G1V 4C7, Canada
SO: HYDROBIOLOGIA 1994 vol. 291, no. 3, pp. 141-156
LA: English
ER: F (Freshwater)
AB: In a study of a large fluvial lake (Lake St. Pierre, St. Lawrence River system, Quebec), we have determined the biomass of the submerged vegetation (dominated by Vallisneria americana and Potamogeton spp) during the peak seasonal biomass (August) and senescence (October), and have estimated the content of Cd, Cr, Cu, Ni, Pb and Zn in the above-ground portions of these plants. Multispectral remote sensing data (MEIS-II) were used to extrapolate from point measures of biomass (g m super(-2)) to the entire area of the lake. By combining field information (biomass values and metal concentrations) with the more extensive remote sensing data base of biomass values, and by using geostatistical estimation techniques (kriging), we have estimated the seasonal storage of metals in Lake St. Pierre plants to be: 30 kg Cd, 89 kg Cr, 450 kg Cu, 280 kg Ni, 71 kg Pb and 2200 kg Zn. During the seasonal biomass peak, the quantities of Cd, Pb and Zn stored in the plants were higher than those dissolved in the water column, but much lower than those present in the surficial, recent sediments. Mass balance calculations for the summer months indicated that the 'macrophyte' compartment represented only a small proportion of the metals entering the lake: Cu and Ni, <1%; Cd and Zn, 2%; Pb, 4%. Senescence and the downstream drifting of plant material noted in October suggested that most of the metals associated with the above-ground parts of the submerged vegetation were not recycled within the lake, but instead were exported at the end of the summer.
AN: 3734919
340 of 1521
TI: The biogeochemical cycling of elemental mercury: Anthropogenic influences
AU: Mason,-R.P.; Fitzgerald,-W.F.; Morel,-F.M.M.
AF: Ralph Parsons Lab., MIT, Cambridge, MA 02139, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 15, pp. 3191-3198
NT: The Clair C. Patterson Special Issue.
LA: English
ER: M (Marine)
AB: A review of the available information on global Hg cycling shows that the atmosphere and surface ocean are in rapid equilibrium; the evasion of Hg super(0) from the oceans is balanced by the total oceanic deposition of Hg(II) from the atmosphere. The rapid equilibrium of the surface oceans and the atmosphere, coupled with the small Hg sedimentation in the oceans makes deposition on land the dominant sink for atmospheric Hg. About half of the anthropogenic emissions appear to enter the global atmospheric cycle while the other half is deposited locally, presumably due to the presence of reactive Hg in flue gases. We estimate that over the last century anthropogenic emissions have tripled the concentrations of Hg in the atmosphere and in the surface ocean. Thus, two-thirds of the present Hg fluxes (such are deposition on land and on the ocean) are directly or indirectly of anthropogenic origin. Elimination of the anthropogenic load in the ocean and atmosphere would take fifteen to twenty years after termination of all anthropogenic emissions.
AN: 3734912
341 of 1521
TI: Reactive trace metals in the stratified Central North Pacific
AU: Bruland,-K.W.; Orians,-K.J.; Cowen,-J.P.
AF: Inst. Mar. Sci., Univ. California Santa Cruz, Santa Cruz, CA 95064, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 15, pp. 3171-3182
NT: The Clair C. Patterson Special Issue.
LA: English
ER: M (Marine)
AB: Vertical concentration profiles of the dissolved and suspended particulate phases were determined for a suite of reactive trace metals, Al, Fe, Mn, Zn, and Cd, during summertime at a station in the center of the North Pacific gyre. Reactive trace metals exhibit a range of biogeochemical behaviors that can be characterized by two endmembers, nutrient-type and scavenged-type. Nutrient-type metals, best exemplified by Zn and Cd, are primarily removed from surface waters by biogenic particles and then remineralized at depth. Internal biogeochemical cycles together with physical mixing and circulation patterns control the distributions of nutrient-type metals. Scavenged-type metals, best exemplified by Al, continue to be removed onto particles in intermediate and deep waters as well as at the surface. External inputs, such as the deposition of aeolian dust, control the concentrations and distributions of scavenged-type metals. Other metals, such as Fe, exhibit a mixture of the characteristic behaviors of these two endmembers.
AN: 3734849
342 of 1521
TI: Impact of UV-B radiation on pelagic freshwater ecosystems: Report of working group on bacteria and phytoplankton
AU: Karentz,-D.; Bothwell,-M.L.; Coffin,-R.B.; Hanson,-A.; Herndl,-G.J.; Kilham,-S.S.; Lesser,-M.P.; Lindell,-M.; Moeller,-R.E.; et-al.
AF: Dep. Biol., Univ. San Francisco, San Francisco, CA 94117-1080, USA
SO: IMPACT-OF-UV-B-RADIATION-ON-PELAGIC-FRESHWATER-ECOSYSTEMS STUTTGART-FRG SCHWEIZERBART'-SCHE-VERLAGSBUCHHANDL. 1994 no. 43 no. 43, pp. 31-69
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 43
NT: Bibliogr.: 5 ref. pages
LA: English
ER: F (Freshwater)
AB: Ultraviolet B (UV-B) radiation has always been an important environmental factor. Recent global trends in stratospheric ozone depletion could increase the amount of UV-B within aquatic environments and this has generated a growing interest in how UV-B can affect aquatic ecosystems. While much has been learned about the UV photobiology and photochemistry of natural waters, evaluating ecosystem responses is a very complex task. This report summarizes biological and hydrological data related to UV-B exposure. Gaps in our knowledge are indicated and the potential effects of increased UV-B on pelagic freshwater ecosystems are discussed. Appendices include an extensive bibliography relating to the UV-photobiology of aquatic microorganisms and macroalgae.
AN: 3732894
343 of 1521
TI: Use of nutrient diffusing substrata to assess nutrient limitation in a stream impacted by agriculture and silviculture
AU: Nord,-B.; Toetz,-D.*
AF: Dep. Zool., Oklahoma State Univ., Stillwater, OK 74078, USA
SO: J.-FRESHWAT.-ECOL. 1994 vol. 9, no. 4, pp. 289-298
LA: English
ER: F (Freshwater)
AB: The nutrient status of streams impacted by agriculture and silviculture is little known, especially in Oklahoma and Arkansas, USA. In this research the authors assessed the impact of nutrients on biofilms in the Glover River, Oklahoma, which drains a watershed impacted by poultry manure, clear-cutting, and forest fertilization. They used nutrient diffusing substrata with two independent measures of biomass and N:P ratios to assess N and P limitation in this stream during 1988-1990. The substrata data revealed limitation by N. However, N:P supply ratios indicated P limitation during 1990. The nutrient regime, turbidity and discharge changed radically during the study. Caution is advised in use of nutrient diffusing substrata in streams impacted by high turbidity and high discharge.
AN: 3732514
344 of 1521
TI: Mercury and arsenic distribution in Lake Champlain sediments
AU: Fuller,-R.D.; McIlroy,-L.M.; Demarte,-B.L.; Lassell,-C.M.; King,-J.W.; Appleby,-P.; McIntosh,-A.W.
AF: Cent. Earth Environ. Sci., SUNY, Plattsburgh, NY 12901, USA
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 136
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Distributions of mercury and arsenic in sediments of Lake Champlain were studied as part of an overall research effort sponsored by the Lake Champlain Management Conference examining fate and effects of pollutants in Lake Champlain. Mercury concentrations are of concern due to elevated levels in fish tissue. Arsenic distribution is noteworthy because its deposition via the atmosphere is among the highest in the northeastern U.S. An initial screening survey of the top two cm of sediments was performed at 30 sites throughout the lake. Based on the distribution of toxic pollutants in this survey, nine sites were selected for extraction of sediment cores to ascertain pollution history. Surface sediment concentrations ranged from 0.05 to 0.89 mg/kg for mercury and 3.6 to 39.7 mg/kg for arsenic. Sediment mercury values are representative of average ranges found in the Great Lakes, whereas arsenic concentrations are higher. Concentrations of mercury were highest in the embayments of Burlington, Vt. and Plattsburgh N.Y. Arsenic concentrations were highest in Mallett's Bay, Vt. Core profile mercury concentrations increased with depth near the sediment-water interface and then decreased to relatively low background concentrations. In contrast to mercury profiles, arsenic concentrations were generally highest at the interface and decreased with depth.
AN: 3731246
345 of 1521
TI: Virtual elimination of toxic and persistent chemicals from Lake Superior, a mass balance study
AU: Mackay,-D.; Sang,-S.; Diamond,-M.L.; Vlahos,-P.; Dolan,-D.; Voldner,-E.
AF: Inst. Environ. Stud., Univ. Toronto, Toronto, ON M5S 1A4, Canada
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 133
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: In recent years several mass balancing projects have been undertaken to establish the linkage between the loadings of specific chemicals and concentration of these chemicals in the water, sediment, and biota of the Great Lakes. A simple "rate constant" model have been developed by Mackay et al (1993) which is the basis of the present paper. The rate constant model has been modified for Lake the Superior and is applied to PCBs and lead. The structure of the model is described and its results are discussed. The model can be used to establish a range of reasonable virtual elimination scenarios for the two chemicals. It is concluded that any efforts to virtually eliminate chemicals from the Great Lakes must be based on understanding the sources and fate of the chemicals in question. The use of mass balance model helps to quantify these sources and eliminate the insignificant processes and sources. An ongoing effort is needed to expand the model to include primary sources, atmospheric transport from primary sources and Watershed retention.
AN: 3731242
346 of 1521
TI: A mass balance analysis of mercury in lakes Ontario and Superior
AU: Diamond,-M.L.; Mackay,-D.; Sang,-S.
AF: Dep. Geogr., 100 St. George St., Univ. Toronto, Toronto, ON M5S 1A1, Canada
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 133
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: A multi-species balance model based on the fugacity/aquivalence approach has been developed and applied to mercury in Lakes Ontario and Superior. The model links land-based and atmospheric loadings of elemental, inorganic and methyl mercury to concentrations and movement in water, surface sediment and air. Given the steady-state proportions of each species in each phase, the model provides estimates of net species interconversion in water and sediment. Most mercury entering and within the lakes is inorganic with roughly equal amounts being buried in and exported from Lake Ontario, and most being buried in Lake Superior. About 10% of total inputs is reduced to elemental mercury in the water column which then volatilizes. The estimated persistence of total mercury in the water and sediments of 5 and 20 years for Lakes Ontario and Superior is relatively short considering water renewal times of 6.5 and 191 years, respectively. To reduce mercury concentrations in Lake Ontario land-based sources must be controlled whereas atmospheric sources must be reduced for Lake Superior. Unlike other inorganics but similarly to persistent volatile organics, the response of the lakes to loading reductions will be prolonged as mercury cycles and recycles between the atmospheric pool and lakes and terrestrial systems.
AN: 3731241
347 of 1521
TI: MICHTOX, a mass balance and bioaccumulation model for toxic chemicals in Lake Michigan
AU: Endicott,-D.D.; Richardson,-W.L.; Kandt,-D.J.
AF: USEPA, Large Lakes Res. Stn., Grosse Ile, MI, USA
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 143
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: A mass balance and bioaccumulation model for priority toxic chemicals was developed for Lake Michigan. The objectives of modeling were (1) to demonstrate the utility of the mass balance approach for the Lake Michigan Lakewide Management Plan (LaMP), and (2) present mass balance study design alternatives to provide various levels of accuracy and resolution. The model was validated using data for plutonium, lead and polychlorinated biphenyls (PCBs) - toxics for which loadings could be reliably estimated. The utility of the model was demonstrated by predicting the effectiveness of several alternative PCB load reduction scenarios. Uncertainty analysis (Bayesian Monte Carlo) was used to estimate the reliability of predictions, both before and after model calibration to field data. The effects of system lag time and independent atmospheric concentration upon the relationship between chemical loads and concentrations are illustrated.
AN: 3731219
348 of 1521
TI: Gas cycling at the sediment-water interface of Lake Taupo, New Zealand
AU: Adams,-D.D.
AF: Cent. Earth Environ. Sci., State Univ. New York, Plattsburgh, NY 12901, USA
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 91
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Dissolved gases (O sub(2), CH sub(4), N sub(2) and N sub(2)O) and other redox species (NO sub(2), NO sub(3) and SO sub(4)) were measured at 3-mm intervals near the sediment-water interface (SWI) to asses oxidation/reduction as related to the microbial cycling of C and N. The penetration of oxygen into the surface sediments averaged 5-6 mm, with a calculated flux to the SWI of 3 to 5 mM m super(-2) d super(-1) depending on the site and variability between cores. The calculated upward diffusive flux of CH sub(4) (1-2 mM m super(-2) d super(-1)) to the interface accounted for 60-70% of the oxygen consumption. Concentration profiles in the sediments of N sub(2)O (range of 0.03-0.14 uM) and N sub(2) (0.8-2.7 mM) suggest active zones of nitrification and denitrification. N sub(2) gas was always highly supersaturated in these surface sediments compared to overlying waters within 0-5 cm of the SWI. During the 1990-1991 period, an additional 16 gravity cores at four sampling sites were collected to obtain further information about porewater gases and other chemical variables; microelectrode oxygen profiles were also measured in 68 cores.
AN: 3731182
349 of 1521
TI: Application of the QWASI fugacity/aquivalence model to assessing the fate of contaminants in the water and sediment of Hamilton Harbour
AU: Ling,-H.; Diamond,-M.; Mackay,-D.
AF: Inst. Environ. Stud., Univ. Toronto, Toronto, ON M5S 1A4, Canada
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 70
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Three simple steady-state mass balance models based on the QWASI (Quantitative Water Air Sediment Interaction) fugacity/aquivalence model have been developed for Hamilton Harbour. These models correspond to three types of compartmentalization, i.e. (1) epilimnion, hypolimnion, and surficial sediment during summer months, (2) a single water column and surficial sediment during other seasons, and (3) a single water column and two surficial sediment compartments to account for sediment focusing. Processes treated are chemical emissions, advective inflows, atmospheric deposition, diffusion between air and water, and between sediment and water, sediment deposition, resuspension, and burial, transformation reactions in water and sediment, mass exchange between epilimnion and hypolimnion, and advective outflows. The models describe the fate of four chemicals, PCBs, B(a)P, Pb, and Zn. A complete picture of the behavior of these chemicals in the Harbour is deduced and the time responses of the system inferred. The results illustrate the relative importance of the various partitioning, transport, transformation processes, and of the various sources of contaminants including sediment-water transfer. It is suggested that most of the chemicals do not persist in the Harbour water and surface sediment longer than 3 years, that the major contamination sources are industrial emissions, or STPs, and that the sediment is of secondary importance as a source. The application of mass balance models for remedial action planning is discussed.
AN: 3731151
350 of 1521
TI: Closing off the southern ocean surface
AU: Heinze,-C.; Broecker,-W.S.
AF: Max-Planck-Inst. Meteorol., Hamburg, Germany
SO: PALEOCEANOGRAPHY 1995 vol. 10, no. 1, pp. 49-58
LA: English
ER: M (Marine)
AB: Equilibrium integrations with the three-dimensional Hamburg ocean carbon cycle circulation model show the effect of a Southern Ocean surface outcrop that is closed off for gas exchange with the atmosphere and export production of particulate organic carbon and CaCO sub(3) south of 32.5 degree S. For such a close-off, the northern Atlantic outcrop assumes a greater degree of control of atmospheric CO sub(2) partial pressure. Contrary to expectations, the atmospheric pCO sub(2) increases compared to a control run without close-off. Maximizing the nutrient utilization in the North Atlantic can compensate for this increase. However, it does not draw down the pCO sub(2) to glacial levels.
AN: 3731035
351 of 1521
TI: Sensitivity of the phosphate-cadmium-carbon isotope relation in the ocean to cadmium removal by suboxic sediments
AU: Van-Geen,-A.; McCorkle,-D.C.; Klinkhammer,-G.P.
AF: Lamont-Doherty Earth Obs. Columbia Univ., Palisades, NY, USA
SO: PALEOCEANOGRAPHY 1995 vol. 10, no. 2, pp. 159-170
LA: English
ER: M (Marine)
AB: Reconstructions of past deep ocean nutrient concentrations rely largely on the carbon isotopic composition and cadmium content of shells of benthic foraminifera. When comparing records of these two paleonutrient tracers, a relation similar to the phosphate-cadmium-carbon isotope relation in the water column today is generally assumed. We present new water column, sediment, and pore water data from the California continental margin which demonstrate that Cd accumulation is enhanced in suboxic sediments. These results suggest that the oceanic Cd inventory is sensitive to changes in the areal extent and redox intensity of suboxic sediments and thus that the phosphate-cadmium relation in the ocean could have been different in the past. The magnitude of this effect and its evolution through time is presently hard to quantify because the oceanic Cd budget is poorly constrained.
AN: 3731019
352 of 1521
TI: Sulphate reduction in the hypolimnion and sediments of Lake Kinneret, Israel
AU: Hadas,-O.; Pinkas,-R.
AF: Israel Oceanogr. and Limnol. Res., Yigal Allon Kinneret Limnol. Lab., P.O. Box 345, Tiberias 14102, Israel
SO: FRESHWAT.-BIOL. 1995 vol. 33, no. 1, pp. 63-72
LA: English
ER: F (Freshwater)
AB: Lake Kinneret is a warm monomictic lake. Between January and June a heavy annual bloom of the dinoflagellate Peridinium gatunense dominates phytoplankton biomass. At the beginning of the summer, degradation and decomposition of the Peridinium biomass occurs, serving as a trigger for intense sulphate reduction in the hypolimnion and sediments. The rates of sulphate reduction in the sediments varied seasonally from 12 to 1700 nmol SO sub(4) super(-2) reduced cm super(-3)/day in December and July, respectively. The availability of organic matter and sulphate is high in June after the crash of the Peridinium bloom and the beginning of stratification and is lowest in December before overturn. The lake is not depleted of sulphate at any time, so the sulphate reduction process in Lake Kinneret is not limited by sulphate concentrations except in the sediments just before overturn.
AN: 3729603
353 of 1521
TI: Biolimitation of iodine distribution in Antarctic Ocean
AU: Cheng,-Xianhao; Pan,-Jianming; Zhang,-Haisheng; Zhang,-Ping
AF: 2nd Inst. Oceanogr., SOA, Hangzhou 310012, People's Rep. China
SO: OCEANOL.-LIMNOL.-SIN.-HAIYANG-YU-HUZHAO 1994 vol. 25, no. 1, pp. 38-47
LA: Chinese
ER: M (Marine)
AB: Based on the analysis of samples collected during Sixth Chinese Antarctic Exploration, this paper discusses the geochemical distribution of iodine species and chemical forms. Special interest is directed to the relations among the iodine species, and parameters related organism activity. The concentrations of total inorganic iodine are from 0.267 to 0.443 mu mol/dm super(3) (mostly iodate) in the surface seawater. There are closely relations between nutrients and the concentrations of iodine and iodate. The results shows dissolved organic iodine concentration distributes stably horizontally and vertically is about 10% of the total inorganic iodine. The absorption and assimilation rate of phytoplankton for iodine is about 0.17 mu mol/(m super(2)/d); the associated iodine as suspended organic particulates is about 4.3 mu mol/m super(3), in which the iodine instanding crop averages 16%. The deposit rate of the particulate iodine is more than 7.2 d/m, within the euphotic zone. A biogeochemical cycle model is proposed.
AN: 3729425
354 of 1521
TI: Mineralogical and geochemical compositions of modern bivalve shells from the Mediterranean coast of Egypt
AU: Holail,-H.; Tony,-R.
AF: Univ. Qatar, Fac. Sci., Geol. Dep., P.O. 2713, Doha-Qatar
SO: GEOJOURNAL 1995 vol. 35, no. 4, pp. 481-486
LA: English
ER: M (Marine)
AB: The stable isotopic composition ( delta super(13)C and delta super(18)O) and elemental (Sr and Mg) of marine molluscs are presented for Carditacea and Solenacea shells collected off the Mediterranean coast of Egypt. Based on shell microstructures and mineralogy, the bivalve shells are preserved in their original mineralogy and chemistry. The Sr and Mg concentrations of the bivalve shells have mean values of 1960 ppm and 226 ppm respectively. The stable isotopic composition generally show high values of delta super(18)O and delta super(13)C. The delta super(18)O values range from +0.1 to -1.8ppt PDB and most shells are highly enriched in super(13)C; averaging +2.5ppt PDB. These elemental and isotopic signatures are analogous to modern marine bivalves from other localities. The oxygen and carbon isotopes, together with the calculated temperatures, suggest that the aragonitic bivalve shells were precipitated in isotopic equilibrium from warm marine waters.
AN: 3729389
355 of 1521
TI: Effects of marine sediment resuspension on organic matter processing in coastal environments: A simulation model
AU: Wainright,-S.C.; Hopkinson,-C.S.,Jr.
AF: Inst. Mar. and Coast. Sci., Rutgers Univ., New Brunswick, NJ 08903-0231, USA
CO: 23. Benthic Ecology Meeting, New Brunswick, NJ (USA), 17-19 Mar 1995
SO: TWENTY-THIRD-BENTHIC-ECOLOGY-MEETING. Grassle,-J.P.;Kelsey,-A.;Oates,-E.;Snelgrove,-P.V.-eds. Rutgers-the-State-Univ.,-New-Brunswick,-NJ-USA.-Inst.-Marine-Coastal-Sciences 1995 vp
NT: Abstract only.
LA: English
ER: M (Marine)
AB: A model, constructed using STELLA super(TM), was used to simulate changes in standing stocks and flows of organic matter resulting from sediment resuspension in shallow coastal environments. Previous studies suggested that resuspension may determine the sites and rates of organic matter mineralization in shallow environments. Those studies predicted that resuspended organic material could exert an enhanced demand on dissolved oxygen and could contribute towards shifting the system metabolic balance towards heterotrophy. Our model results confirm these hypotheses. Total system metabolism (benthic + pelagic) received an increasing contribution from the water column as settling rate decreased, and as the frequency and intensity of resuspension events increased. Furthermore, total system metabolism increased in response to resuspension.
AN: 3729343
356 of 1521
TI: The use of natural strontium isotopes as tracers in environmental studies
AU: Aaberg,-G.
AF: Inst. Energy Technol., Box 40, N-2007 Kjeller, Norway
CO: BIOGEOMON, The Symposium on Ecosystem Behaviour: Evaluation of Integrated Monitoring in Small Catchments, Prague (Czech Rep.), 18-20 Sep 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1995 vol. 79, no. 1-4, pp. 309-322
LA: English
ER: F (Freshwater)
AB: Naturally occurring isotopes of elements like strontium have proved to be good tools for tracing the past and for monitoring of processes in the present. The spread and variation in super(87)Sr/ super(86)Sr ratios make Sr isotopes a powerful tool when it comes to detecting trends in the soil-vegetation system. There is also a great potential in combining different parameters like soil, water, biological material and isotopes for detecting environmental changes over short as well as long time periods. Sampling of the past is a difficult task but biological material, in combination with inorganic material, proves advantageous as environmental archives. There is also the possibility of using museum collections as environmental historic archives. This paper discusses the potential of using the natural super(87)Sr/ super(86)Sr ratio as a tracer for environmental studies. The results presented point to an ongoing impoverishment of the environment and show that the temporal trend in Sr isotope composition for different media is similar despite material and location of test area.
AN: 3729340
357 of 1521
TI: Biogeochemistry of dissolved hydrogen sulfide species and carbonyl sulfide in the western North Atlantic Ocean
AU: Radford-Kncery,-J.; Cutter,-G.A.
AF: IFREMER, Dep. DRO/GM, B.P. 70, F-29280 Plouzane, France
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 24, pp. 5421-5431
LA: English
ER: M (Marine)
AB: The biogeochemistry of total sulfide dissolved in the open ocean is a poorly understood component of the global sulfur cycle. Here, the cycling of total sulfide was examined in the western North Atlantic Ocean using specially developed sampling and analytical methods. Sources of total sulfide were examined. In particular, the rate of carbonyl sulfide (OCS) hydrolysis was redetermined under oceanographic conditions, and the depth distribution of OCS was examined. The patterns of near-surface enrichment (up to 150 pmol/L) and depletion at depth observed in OCS depth profiles suggest in situ production of OCS. To quantify the sources and sinks of total sulfide in the mixed layer of the Sargasso Sea, a budget was constructed. The significant difference between the known sources and sinks indicates that other processes are important for the cycling of sulfide.
AN: 3729223
358 of 1521
TI: Effect of UV-B radiation on the fatty acid composition of the marine phytoplankter Tetraselmis sp.: Relationship to cellular pigments
AU: Goes,-J.I.; Handa,-N.; Taguchi,-S.; Hama,-T.
AF: Inst. Hydros.-Atmos. Sci., Nagoya Univ., Chikusa-ku 464, Japan
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 114, no. 3, pp. 259-274
NT: Bibliogr.: 71 ref.
LA: English
ER: M (Marine)
AB: The effect of UV-B (280 to 320 nm) radiation on the fatty acid and pigment composition of Tetraselmis was examined as part of a larger effort to understand the possible consequences of an enhancement in natural levels of UV-B radiation on photosynthetic processes in marine phytoplankton. At levels that still permitted the assimilation of carbon within the cell, UV-B radiation induced a rapid increase in intracellular carotenoids and a marked decline in chlorophyll a. Absolute concentrations of fatty acids within the cells were lower in presence of UV-B, attributable largely to suppression of polyunsaturated fatty acid (PUFA) synthesis. The suppression of PUFAs by UV-B radiation and the inability of the cells to produce these compounds in the dark suggests that over a diel cycle, if natural phytoplankton are exposed to UV-B radiation during the day, the cells may be incapable of restoring the cellular balance of fatty acids during the night. Amongst the PUFAs, the production of 16:4 was highly susceptible to UV-B radiation. In contrast, the production of the saturated fatty acid 16:0 continued unabated in the presence of UV-B radiation. The carbon weight ratio of 16:0 to 16:4 related well with the dose of UV-B radiation and appears to be a promising indicator of UV-B induced stress in green algae. A hypothesis explaining the selective suppression of cellular PUFA synthesis, in particular that of 16:4 by UV-B, is presented and discussed in relation to concurrent changes in intracellular pigments. The implications of enhanced UV-B radiation on the marine food chain and on biogeochemical cycling in the sea are discussed in the light of these findings.
AN: 3729084
359 of 1521
TI: Microbial-mineral floc associated with nascent hydrothermal activity on CoAxial segment, Juan de Fuca Ridge
AU: Juniper,-S.K.; Martineu,-P.; Sarrazin,-J.; Gelinas,-Y.
AF: GEOTOP, Univ. Quebec, Montreal, PQ, Canada
SO: GEOPHYS.-RES.-LETT. 1995 vol. 22, no. 2, pp. 179-182
LA: English
ER: M (Marine)
AN: 3726987
360 of 1521
TI: Elemental and major biochemical changes across an oxidation front in a relict turbidite: An oxygen effect
AU: Cowie,-G.L.; Hedges,-J.I.; Prahl,-F.G.; De-Lange,-G.J.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada
SO: GEOCHIM.-COSMOCHIM.-ACTA 1995 vol. 59, no. 1, pp. 33-46
LA: English
ER: M (Marine)
AB: The elemental and major biochemical compositions of the relict f-turbidite sampled in two cores from the Madeira Abyssal Plain were determined. This fine-grained, distal sequence occurs at ca. 9 m core depth and includes a surficial oxidized horizon defined by a distinct color change. Oxygen diffused downward through sediments above this interface and in ca. 10 kyr destroyed 80% of the organic substances that below the front had survived degradation in the presence of porewater sulfate for ca. 140 kyr. These deposits provide an opportunity to establish the extent and selectivity of oxic sedimentary degradation under natural conditions without the usual complications of bioturbation and varying sources or sedimentation rates. This study demonstrates that prolonged exposure to O sub(2) can lead to organic matter alteration which is far more extensive than that obtained with sulfate alone. In comparison to early diagenesis, however, alteration of the measured biochemicals was largely nonselective. Such oxidation reactions could control the distribution and composition of organic matter in slowly accumulating continental rise and deep-ocean environments.
AN: 3726481
361 of 1521
TI: Rapid bacterial degradation of polysaccharides in anoxic marine systems
AU: Arnosti,-C.; Repeta,-D.J.; Blough,-N.V.
AF: Max-Planck Inst. Mar. Mikrobiol., Fahrenheitstr. 1, D-28359 Bremen, FRG
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 12, pp. 2639-2652
LA: English
ER: M (Marine)
AB: Extracellular hydrolysis of organic macromolecules is often assumed to be the slow step in remineralization of organic matter. We tested this assumption by comparing the degradation of four polysaccharides (pullulan, laminarin, and two polysaccharides isolated from the marine cyanobacterium Synechococcus WH7335) to determine whether size, linkage position, or anomeric linkage affected rates or mechanisms of carbohydrate degradation by mixed cultures of anaerobic bacteria enriched from marine sediments. NMR spectra showed that preferential hydrolysis occurred at specific chemical linkages, and extracellular enzymatic hydrolysis of polysaccharides occurred far more rapidly than bacterial uptake and remineralization of the lower molecular weight oligosaccharides produced through enzymatic hydrolysis. Substrate size was not a significant determinant of remineralization rate: high molecular weight does not always correlate with slow degradation rate.
AN: 3726453
362 of 1521
TI: Predator-prey interactions between Isochrysis galbana and Oxyrrhis marina. 3. Mathematical modelling of predation and nutrient regeneration
AU: Davidson,-K.; Cunningham,-A.; Flynn,-K.J.*
AF: Algal Res. Unit, Sch. Biol. Sci., Univ. Wales, Swansea, Singleton Park, Swansea SA2 8PP, UK
SO: J.-PLANKTON-RES. 1995 vol. 17, no. 3, pp. 465-492
LA: English
ER: M (Marine)
AB: A mathematical model was derived to simulate ingestion, growth and nitrogen (N) regeneration for the phagotrophic dinoflagellate Oxyrrhis marina. Two types of experimental study were undertaken: prey-deplete O. marina were supplied with Isochrysis galbana in continuous darkness (thus preventing growth of the prey), and the predator-prey interactions were also followed in cultures maintained in a light-dark cycle (allowing growth of the prey). During light-dark cycles, Oxyrrhis volume increased more in the light phase than in the dark. Digestion of Isochrysis lasted similar to 0.3 days, with an average maximum ingestion rate of 55 prey/predator/day. During active predation, 30% of Oxyrrhis-carbon (C) was lost from the particulate phase: per day, with this loss falling to 10%: per day at the cessation of herbivory when cannibalism became noticeable. Ingestion was modelled as a function of prey density, C-loss and division as functions of cellular predator C, with cannibalism by Oxyrrhis also included. Two N-regeneration expressions were investigated: one proposed by D.A. Caron and J.C. Goldman (Journal of Protozoology, 5, 247-249, 1988) and an alternative function which related N regeneration to intracellular carbon and N based on the concept of an optimal Oxyrrhis C:N ratio. The latter was more successful in simulating batch culture data and did not require a prior calculation of Oxyrrhis gross growth efficiency. The model of Oxyrrhis numbers, C and N contained only nine parameters whose values were fully obtainable from batch culture experiments. By using this model, we were able to use a single parameter set to simulate the transient dynamics of Oxyrrhis ingesting N-replete and N-stressed prey. Further experiments in which Oxyrrhis grew on Isochrysis in light-dark cycles were simulated by combining the Oxyrrhis model with the nutrient-processing model for Isochrysis of K. Davidson et al. (Journal of Plankton Research, 15, 351-359, 1993). The dynamics of the full predator-prey model were found to be sensitive to the level of sophistication of the prey model; the Quota model was found to be less successful than the nutrient-processing prey model. Theoretical model runs indicated the importance of being able to simulate changes in both prey numbers and biomass, and also in including realistic equations for nutrient regeneration from predators in microbial predator-prey models.
AN: 3725499
363 of 1521
TI: The potential of denitrification for intercepting groundwater nitrate in a salt marsh ecosystem
AU: Hee,-C.; Howes,-B.L.; Weiskel,-P.K.
AF: Univ. Scranton, Scranton, PA 18510, USA
CO: 23. Benthic Ecology Meeting, New Brunswick, NJ (USA), 17-19 Mar 1995
SO: TWENTY-THIRD-BENTHIC-ECOLOGY-MEETING. Grassle,-J.P.;Kelsey,-A.;Oates,-E.;Snelgrove,-P.V.-eds. Rutgers-the-State-Univ.,-New-Brunswick,-NJ-USA.-Inst.-Marine-Coastal-Sciences 1995 vp
NT: Abstract only.
LA: English
ER: M (Marine)
AB: The rates and controls of microbial denitrification were studied at Namskaket Marsh, Orleans MA in order to determine the capacity of the marsh to remove nitrate carried by inflowing groundwater. The marsh is located at the discharge of a groundwater nitrate plume generated by a septage treatment plant established in February 1990. Denitrification rates were measured as the disappearance of nitrate over time from water overlying creek bottom sediments in the summer of 1994 (19 C). Rates of denitrification ranged from 277 to 604 umoles/m super(2)/hr. Nitrate and carbon addition experiments were conducted in the creek bottoms and with sediments from below the rooting zone of the vegetated marsh slurried with acetylene. The rate of denitrification was stimulated by both nitrate and carbon additions. Both nitrate and carbon are limiting at current conditions in the creek bottoms and at the seepage front.
AN: 3724277
364 of 1521
TI: Bacterial activity in NW Mediterranean seagrass (Posidonia oceanica) sediments
AU: Lopez,-N.I.; Duarte,-C.M.*; Vallespinos,-F.; Romero,-J.; Alcoverro,-T.
AF: Cent. Estuad. Ave. Blanes, CSIC, Cami St. Barbara s/n, 17300 Blanes, Girona, Spain
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1995 vol. 187, no. 1, pp. 39-49
LA: English
ER: M (Marine)
AB: We examine here the hypothesis that benthic bacterial activity in seagrass [Posidonia oceanica (L.) Delile] meadows is dependent on seagrass growth and availability of inorganic nutrients in the sediments. This was achieved by measuring bacterial activity (ammonification rates, and exoproteolytic and exoglucosidase activities) during an annual cycle in five P. oceanica and meadows in the NW Mediterranean. Benthic bacterial activity was high, and tended to increases with increasing seagrass production. This trend is likely to involve a direct effect derived from the greater supply of organic carbon in productive meadows, and an indirect effect derived from the fact that productive meadows develop over nutrient-rich sediment and yield nutrient-rich detritus. Phosphorus availability to bacteria was low, for plant detritus was deficient in phosphorus relative to bacterial requirements, and bacterial activity was reduced after seagrasses depleted inorganic phosphorus from the sediments at the onset of exponential plant growth. These results indicate that, on local and annual time scales, benthic bacterial activity is directly related to seagrass production in the NW Mediterranean, because of enhanced inputs of organic matter by the seagrasses, while on seasonal scales, bacteria and seagrass metabolism are inversely related, apparently because of competition for inorganic nutrients.
AN: 3724262
365 of 1521
TI: Impact of the soft-shell clam, Mya arenaria burrows on sulfate reduction in an intertidal sediment
AU: Hansen,-K.; King,-G.M.
AF: Inst. Biol., Odense Univ., DK-5230 Odense M, Denmark
CO: 23. Benthic Ecology Meeting, New Brunswick, NJ (USA), 17-19 Mar 1995
SO: TWENTY-THIRD-BENTHIC-ECOLOGY-MEETING. Grassle,-J.P.;Kelsey,-A.;Oates,-E.;Snelgrove,-P.V.-eds. Rutgers-the-State-Univ.,-New-Brunswick,-NJ-USA.-Inst.-Marine-Coastal-Sciences 1995 vp
NT: Abstract only.
LA: English
ER: M (Marine)
AB: The effect of the soft-shell clam Mya arenaria on sulfate reduction and various parameters related to the sulfur cycle was examined in an intertidal sediment (Lowes Cove, Maine). Measurements were made at mm intervals around burrows and extending 25 mm into the ambient sediment. Sulfate reduction rates were 1.5-2 times higher in the inner 1-5 mm region surrounding the burrow, whereas pools of reduced S increased with the distance from the burrow wall, being 1.5 times higher in bulk sediment. Enumeration of sulfate reducing bacteria and thiosulfate-disproportionating bacteria were made using the most-probable-number technique. In both cases highest numbers were found in the innermost zone around burrows relative to bulk sediment. The results suggest that Mya burrows are sites of enhanced microbial activity and a dynamics sulfur cycle with turnover times of reduced sulfur compounds increasing with distance from the burrow wall.
AN: 3724261
366 of 1521
TI: Microbial sulfate reduction in deep-sea sediments at the Guaymas Basin hydrothermal vent area: Influence of temperature and substrates
AU: Elsgaard,-L.; Isaksen,-M.F.; Joergensen,-B.B.; Alayse,-A.-M.; Jannasch,-H.W.
AF: Danish Inst. Plant and Soil Sci., Dep. Soil Sci., Res. Cent. Foulum, P.O. Box 23, DK-8830 Tjele, Denmark
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 16, pp. 3335-3343
LA: English
ER: M (Marine)
AB: Microbial sulfate reduction was studied by a super(35)S tracer technique in sediments from the hydrothermal vent site in Guaymas Basin, Gulf of California, Mexico. In situ temperatures ranged from 2.7 degree C in the overlying seawater to > 120 degree C at 30 cm depth in the hydrothermal sediment. The high subsurface rates of sulfate reduction in the hydrothermal vent area was attributed to an enhanced local substrate availability. The overall temperature response of thermophilic sulfate reduction was similar in hydrothermal sediment sampled at different sites. Addition of short-chain fatty acids and yeast extract to the sediment slurries stimulated sulfate reduction rates at all incubation temperatures. No sulfate reduction was detected in the temperature range from 102-120 degree C. Microbial rather than thermochemical sulfate reduction could be a possible source of H sub(2)S in sulfide deposits with formation temperatures at about 100 degree C.
AN: 3722261
367 of 1521
TI: Regeneration rates and potential uptake rates of ammonium in Saginaw Bay water in the presence and absence of zebra mussels during the summer of 1992
AU: Gardner,-W.S.; Cavaletto,-J.F.; Johnson,-J.R.; Cotner,-J.B.,Jr.; Heathe,-R.T.
AF: NOAA Great Lakes Environ. Res. Lab., 2205 Commonwealth Blvd., Ann Arbor, MI 48105, USA
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 97
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: A series of super(15)N-NH sub(4) isotope dilution experiments were conducted on waters, collected from southwestern Saginaw Bay at monthly intervals from June to October, 1992, to determine regeneration rates and "potential" uptake rates for ammonium and to examine direct (excretion) and indirect (food web) effects of zebra mussels (Dreissena polymorpha) on these rates. Potential uptake rates peaked in September and corresponded closely with chlorophyll concentrations. The presence of zebra mussels in the bottles (15 per 4-liter bottle) removed some phytoplankton and sometimes caused potential uptake rates to decrease. Ammonium regeneration rates, in the absence of zebra mussel, followed similar seasonal patterns but, as expected, were lower than potential uptake rates. Community ammonium regeneration rates were consistently increased by the presence of zebra mussels indicating that zebra mussel excretion is an important contributor to ammonium regeneration in regions where the bivalve is abundant.
AN: 3721807
368 of 1521
TI: Diatom assemblages as biotic condition indicators within EMAP-Great Lakes
AU: Kreis,-R.G.; Stoermer,-E.F.; Stevenson,-R.J.
AF: USEPA, LLRS/ERL-Duluth, 9311 Groh Rd., Grosse Ile, MI 48138, USA
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 78
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Diatoms are proposed as indicators of biotic integrity and trophic status in EMAP-GL because of their intrinsic value and the numerous methodological, ecological, and interpretive advantages they offer. Diatoms are a major component of primary producer assemblages in aquatic systems, are often the base of aquatic food webs, are important in biogeochemical cycling, exhibit great diversity, and have public recognition as aesthetic and water intake nuisances. A distinct advantage of using diatoms is the ability to establish the nominal condition using the paleolimnological approach. The paleolimnological approach has wide application, has established methodologies, eliminates the requirement of an index period, will indicate the precultural period of stability, and provide a 200+ year record from a single sampling episode. Multivariate analysis of assemblages will be used to assess deviation from the nominal condition. Metrics such as the proportions of introduced, eutrophic, benthic, cold water, and locally extinct species will also be diagnostically interpreted based on autoecological relationships with water quality parameters as they relate to biotic integrity and trophic status.
AN: 3721790
369 of 1521
TI: The influence of the structure and function of the marine food web on the dynamics of contaminants in Arctic Ocean ecosystems
AU: Alexander,-V.
AF: Inst. Mar. Sci., Sch. Fish. and Ocean Sci., Univ. Alaska, Fairbanks, AK 99775-7220, USA
CO: International Symposium on the Ecological Effects of Arctic Airborne Contaminants, Reykjavik (Iceland), 4-8 Oct 1993
SO: ECOLOGICAL-EFFECTS-OF-ARCTIC-AIRBORNE-CONTAMINANTS. Landers,-D.H.;Christie,-S.J.-eds. vol. 160-161 pp. 593-603
ST: SCI.-TOTAL-ENVIRON. 1995 vol. 160-161
LA: English
ER: M (Marine)
AB: This paper examines some features of arctic marine ecosystems that may render them vulnerable to airborne pollutants. These features include the seasonal and spatial focus of primary productivity, the allocation of a relatively large proportion of the newly fixed carbon to the benthos, the prevalence of large mammals as apex consumers, and relatively high lipid levels in many arctic species. Sea ice is an important factor, since pollutants falling onto the ice surface during the winter months can be concentrated in epontic particulate matter (at the ice/seawater interface), or, more likely, be released through melting of the ice and enter the planktonic system in spring, reaching the benthos via sedimentation. Two ecosystems are discussed in which these processes are likely to be important - the highly productive Chirikov Basin of the northern Bering Sea and the sea ice-associated community north of Svalbard. There is evidence that pollutants are accumulating in arctic marine ecosystems. However, our predictive ability is constrained by the inability to delineate the sites of deposition.
AN: 3721163
370 of 1521
TI: Leakage of industrial lead into the hydrocycle
AU: Erel,-Y.; Patterson,-C.C.
AF: Inst. Earth Sci., Hebrew Univ., Jerusalem, Israel
CO: Topics in Global Geochemistry, Pasadena, CA (USA), 3-4 Dec 1993
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 15, pp. 3289-3296
LA: English
ER: F (Freshwater)
AB: Quantitative knowledge concerning the contamination effect by industrial Pb migrating through soils into groundwaters has been delineated in a special study carried out in a remote, high altitude mountain valley. Approximately 0.5 ton of industrial Pb has been added in past decades from the atmosphere via precipitation and dry deposition to the 3 km super(2) area of lightly forested and open meadow soil lying within the 13 km super(2) area of the rocky valley. Industrial Pb could be distinguished and its amounts quantitatively determined by use of its unique isotopic composition, which was different from natural Pb in meadow soil. Industrial Pb introduced into the canyon within snow was interacting and exchanging with the larger reservoir of industrial Pb accumulated in canyon soil. Lead in the snow-melt runoff had become attached to soil-derived colloids, and a mixture of industrial and natural particulate Pb was released from the soil to stream water and groundwater. The flux of Pb leached from the accumulated reservoir of industrial Pb in soil could be measured as it flowed through soil pathways into stream runoff waters draining the valley. Such leached industrial Pb comprised about 75% of the total Pb in stream runoff of snow-melt and 20% of the total Pb in stream runoff of groundwater.
AN: 3721114
371 of 1521
TI: Benthic lead fluxes in San Francisco Bay, California, USA
AU: Rivera-Duarte,-I.; Flegal,-A.R.
AF: Earth Sci. Board, Univ. California, Santa Cruz, CA 95064, USA
CO: Topics in Global Geochemistry, Pasadena, CA (USA), 3-4 Dec 1993
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 15, pp. 3307-3313
LA: English
ER: M (Marine)
AB: Porewater concentration gradients indicate relatively large benthic fluxes of Pb from sediments in the San Francisco Bay estuary. Gradients in total dissolved (<0.45 mu m) Pb concentrations in sediment porewaters, which range from 0.07-19.2 nM, parallel gradients in ammonia and dissolved Fe in sediment cores from the bay. Corresponding Fickian diffusive fluxes range from 2.6 x 10 super(-9) moles/m super(2)/d to 3.1 x 10 super(-8) moles/m super(2)/d in anoxic surface (<2 cm) sediments along the periphery of the estuary. These indicate the net diffusive benthic flux of Pb from sediments in San Francisco Bay (3-31 moles d super(-1)) is at least an order of magnitude greater than the fluvial input of dissolved Pb to the estuary (0.2 moles d super(-1)) during low flow periods. Moreover, estimates of the total benthic Pb flux, which were based on Hammond et al. (1985) irrigation benthic flux model, are two- to six-fold greater (6-186 moles d super(-1)) than the estimates of diffusive fluxes. Therefore, the total benthic flux of Pb from the bay's sediments may be within an order of magnitude of the total anthropogenic flux of Pb to the San Francisco Bay estuary (965-8,410 moles/d).
AN: 3721088
372 of 1521
TI: The effects of ecosystem characteristics on contaminant distribution in northern freshwater lakes
AU: Schindler,-D.W.; Kidd,-K.A.; Muir,-D.C.G.; Lockhart,-W.L.
AF: Dep. Zool., CW312 Biol. Sci. Build., Univ. Alberta, Edmonton, AB T6G 2E9, Canada
CO: International Symposium on the Ecological Effects of Arctic Airborne Contaminants, Reykjavik (Iceland), 4-8 Oct 1993
SO: ECOLOGICAL-EFFECTS-OF-ARCTIC-AIRBORNE-CONTAMINANTS. Landers,-D.H.;Christie,-S.J.-eds. vol. 160-161 pp. 1-17
ST: SCI.-TOTAL-ENVIRON. 1995 vol. 160-161
LA: English
ER: F (Freshwater)
AB: Ecological factors can modify the effect of airborne contaminants in arctic freshwater lakes. The detention time of contaminants in lake catchments can greatly affect concentrations and time-courses of contaminant distribution. Lake sediments typically contain concentrations of contaminants several orders of magnitude higher than those in overlying waters, and appear to contain good temporal records of contaminant deposition. They also indicate general increases in contaminant inputs from north to south and from west to east in North America. The lower mean temperatures of northern lakes render them more efficient as sinks for volatile contaminants than warmer lakes in the south. Lower temperatures also cause lower growth rates in fish, resulting in higher concentrations of contaminants. Conversely, the ratio of methylation to demethylation declines in colder temperatures, favoring lower concentrations of mercury in fish. Bioaccumulation can increase contaminant concentrations by several orders of magnitude in food chains of 4-5 steps. Contaminant levels increase with trophic position and are positively correlated with age and fat content, but negatively correlated with growth rates. Stable isotopes appear to be a useful diagnostic tool for examining biomagnification in arctic food chains. Biological transformation and decomposition affect the quantities and toxicity of some pollutants. The effects of some contaminants can be affected by other human stresses, including acid precipitation, climate change, hydroelectric development, harvesting of fishes and marine mammals, and eutrophication. Management of many contaminants requires tradeoffs, such as the beneficial effects of controlling insect-borne pathogens in the tropics versus the negative effects on northern aboriginal populations relying on wild populations of organisms for food.
AN: 3719470
373 of 1521
TI: Litter accession and accumulation in a Melaleuca quinquenervia (Cav.) S.T. Blake wetland in south-eastern Queensland
AU: Greenway,-M.
AF: Fac. Environ. Sci., Griffith Univ., Nathan, Qld 4111, Australia
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1994 vol. 45, no. 8, pp. 1509-1519
NT: Special issue: Plants and processes in wetlands.
LA: English
ER: F (Freshwater)
AB: Litterfall and litter accumulation were investigated over two years in a Melaleuca quinquenervia wetland in south-eastern Queensland. In 1992, a seasonally wet year, litterfall was 809 plus or minus 135 g/m super(2)/yr at the floodplain site and 764 plus or minus 192 g/m super(2)/yr at the riparian site, of which Melaleuca leaf litter made up 65% and 56% respectively. Litterfall was significantly lower and more variable in 1993, a drought year, being 725 plus or minus 106 g/m super(2)/year and 675 plus or minus 216 g/m super(2)/year. There was a distinct seasonal pattern, with peak leaf litterfall occurring in spring in 1992 but extending into summer in 1993. Melaleuca leaf fall was significantly lower in 1993, possibly because drought conditions caused greater leaf longevity. Litter accumulation on the forest floor was 3457 g/m super(2) at the floodplain site and 2320 g/m super(2) at the riparian site; there was no significant difference between years, although the organic matter content of the litter was lower in 1992, possibly as a result of leaching during flooding. Carbon content decreased with decreasing particle size of the litter, whereas nitrogen and phosphorus increased. There was no evidence to suggest leaching of nitrogen or phosphorus, and the high C:N:P ratios indicate slow rates of litter decay. The high accumulation of litter mass suggests that these woody wetlands may function as nutrient sinks.
AN: 3719403
374 of 1521
TI: Methane flux from beds of Baumea arthrophylla (Nees) Boeckeler and Triglochin procerum R. Br. at Bool Lagoon, South Australia
AU: Muller,-K.L.; Ganf,-G.G.; Boon,-P.I.
AF: Dep. Bot., Univ. Adelaide, Adelaide, SA 5005, Australia
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1994 vol. 45, no. 8, pp. 1543-1553
NT: Special issue: Plants and processes in wetlands.
LA: English
ER: F (Freshwater)
AB: The flux of methane from freshwater wetlands is likely to be influenced by the presence of emergent macrophytes. The plants generate an organic loading, which should increase methanogenesis, yet they also aerate the sediment, creating oxic zones inimical to the obligately anaerobic methanogenic bacteria and promoting the oxidation of methane by methanotrophic bacteria. Moreover, emergent plants can act as a conduit for methane to be vented to the atmosphere. Depth profiles of oxygen in beds of B. arthrophylla and T. procerum at Bool Lagoon, South Australia, showed that water at the sediment surface was anoxic during the night but became oxygenated during the latter part of the day. Redox profiles of the sediment gave values that ranged from -50 to +250 mV, indicating a sediment that was not highly reducing. Despite these conditions, the wetlands were sources of significant methane emissions, with total water-atmosphere fluxes ranging from <0.01 to 1.05 mmol m super(-2) h super(-1). The presence of B. arthrophylla, but not that of T. procerum, affected the bubble concentration of methane in the sediments. Diel variations in ebullitive or total methane fluxes were not detected, but emissions varied according to water depth and time of year. Treatments that removed macrophytes reduced total methane fluxes to rates approximately equivalent to ebullition, indicating that the plants were acting as a major pathway for the release of methane to the atmosphere. The lack of a clear diel pattern in emissions suggests that diffusion, rather than convective flow, is the mechanism for this flux through the plants.
AN: 3719401
375 of 1521
TI: A preliminary mass balance model of primary productivity and dissolved oxygen in the Mississippi River plume/Inner Gulf Shelf region
AU: Bierman,-V.J.,Jr.; Hinz,-S.C.; Zhu,-Dong-Wei; Wiseman,-W.J.,Jr.; Rabalais,-N.N.; Turner,-R.E.
AF: Limno-Tech, Inc., 20780 S. Gatehouse Dr., South Bend, IN 46637, USA
SO: ESTUARIES 1994 vol. 17, no. 4, pp. 886-899
NT: Special issue dedicated to papers from NOAA's Nutrient Enhanced Coastal Ocean Productivity Study.
LA: English
ER: M (Marine)
AB: A deterministic, mass balance model for phytoplankton, nutrients, and dissolved oxygen was applied to the Mississippi River Plume/Inner Gulf Shelf (MRP/IGS) region. The model was calibrated to a comprehensive set of field data collected during July 1990 at over 200 sampling stations in the northern Gulf of Mexico. The spatial domain of the model is represented by a three-dimensional, 21-segment water-column grid extending from the Mississippi River Delta west to the Louisiana-Texas border, and from the shoreline seaward to the 30-60 m bathymetric contours. Diagnostic analyses and numerical experiments were conducted with the calibrated model to better understand the environmental processes controlling primary productivity and dissolved oxygen dynamics in the MRP/IGS region. Underwater light attenuation appears relatively more important than nutrient limitation in controlling rates of primary productivity. Chemical-biological processes appear relatively more important than advective-dispersive transport processes in controlling bottom-water dissolved oxygen dynamics. Oxidation of carbonaceous material in the water column, phytoplankton respiration, and sediment oxygen demand all appear to contribute significantly to total oxygen depletion rates in bottom waters. The estimated contribution of sediment oxygen demand to total oxygen-depletion rates in bottom waters ranges from 22% to 30%. Primary productivity appears to be an important source of dissolved oxygen to bottom waters in the region of the Atchafalaya River discharge and further west along the Louisiana Inner Shelf. Dissolved oxygen concentrations appear very sensitive to changes in underwater light attenuation due to strong coupling between dissolved oxygen and primary productivity in bottom waters. The Louisiana Inner Shelf in the area of the Atchafalaya River discharge and further west to the Texas border appears to be characterized by significantly different light attenuation-depth-primary productivity relationships than the area immediately west of the Mississippi Delta. Nutrient remineralization in the water column appears to contribute significantly to maintaining chlorophyll concentrations on the Louisiana Inner Shelf.
AN: 3719304
376 of 1521
TI: Environmental and substrate controls over carbon and nitrogen mineralization in northern wetlands
AU: Updegraff,-K.; Pastor,-J.; Bridgham,-S.D.; Johnston,-C.A.
AF: Nat. Resour. Res. Inst., Univ. Minnesota, Duluth, MN 55811, USA
SO: ECOL.-APPL. 1995 vol. 5, no. 1, pp. 151-163
LA: English
ER: F (Freshwater)
AB: Northern wetlands may be a potential carbon source to the atmosphere upon global warming, particularly with regard to methane. However, recent conclusions have largely been based on short-term field measurements. We incubated three wetland soils representing a range of substrate quality for 80 wk in the laboratory under both aerobic and anaerobic conditions at 15 degree and 30 degree C. The soils were obtained from a Scirpus-Carex-dominated meadow in an abandoned beaver pond and from the surface and at 1 m depth of a spruce (Picea)-Sphagnum bog in Voyageurs National Park, Minnesota. Substrate quality was assessed by fractionation of carbon compounds and summarized using principal components analysis. Nitrogen and carbon mineralization, the partitioning of carbon between carbon dioxide and methane, pH, and Eh were measured periodically over the course of the incubation. The responses of nitrogen mineralization, carbon mineralization, and trace gas partitioning to both temperature and aeration depended strongly on the substrate quality of the soils. Sedge meadow soil had the highest nitrogen and carbon mineralization rates and methane production under anaerobic conditions, and carbon mineralization under aerobic conditions, but the surface peats had the highest nitrogen mineralization rates under aerobic conditions. Methanogenesis was highest in the sedge soil but less sensitive to temperature than in the peats. A double exponential model showed that most of the variation in nitrogen and carbon mineralization among the soils and treatments was accounted for by differences in the size and kinetics of a relatively small labile pool. The kinetics of this pool were more sensitive to changes in temperature and aeration than that of the larger recalcitrant pool. Principal components analysis separated the soils on the basis of labile and recalcitrant carbon fractions. Total C and N mineralization correlated positively with the factor representing labile elements, while methanogenesis also showed a negative correlation with the factor representing recalcitrant elements. Estimates of atmospheric feedbacks from northern wetlands upon climatic change must account for extreme local variation in substrate quality and wetland type; global projections based on extrapolations from a few field measurements do not account for this local variation and may be in error.
AN: 3719257
377 of 1521
TI: Phosphorus and nitrogen mass budgets for Green Bay, 1987-1988 from the Green Bay Mass Balance Study
AU: Warren,-G.; Hughes,-P.E.
AF: U.S. EPA, 77 W. Jackson Blvd., Chicago, IL 60604, USA
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 64
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Total phosphorus and total soluble phosphorus, nitrite-nitrate and ammonia nitrogen concentration information was gathered to support the Green Bay Mass Balance Study. These concentrations, tributary flow and precipitation data are used to calculate loads of nutrients from river and atmospheric sources. This information is combined with ambient Green Bay concentrations from surface water samples taken from the R/V Roger Simons to arrive at a mass budget for nitrogen and phosphorus for the Bay. A comparison of load history for a short period prior to Green Bay sampling surveys will be used to describe the mass movement of the nutrients through the Green Bay system.
AN: 3719191
378 of 1521
TI: Climatically linked carbon isotope variation during the past 430,000 years in Southern Ocean sediments
AU: Singer,-A.J.; Shemesh,-A.
AF: Dep. Environ. Sci. and Energy Res., Weizmann Inst. Sci., Rehovot, Israel
SO: PALEOCEANOGRAPHY 1995 vol. 10, no. 2, pp. 171-177
LA: English
ER: M (Marine)
AB: We use the isotopic composition of carbon from organic matter enclosed within diatom frustules as a proxy for paleoproductivity and paleo-dissolved carbon dioxide concentrations in ocean surface waters. A Southern Ocean record from south of the Antarctic Polar Front and spanning 430,000 years of carbon isotopic variation in diatomaceous organic matter is presented for the first time. The most refractory diatomaceous organic matter fraction was extracted and analyzed to avoid problems associated with diagenesis. The results clearly indicate cyclic changes in organic carbon isotopic ratios, with super(13)C depleted values associated with all of the last five glacial periods, reflecting changes in surface water properties and primary productivity. Changes in dissolved carbon dioxide concentrations are the most probable cause of these cycles, but the possible effect of seawater pH changes cannot be excluded.
AN: 3719187
379 of 1521
TI: A phosphorus mass balance for the Green Bay ecosystem
AU: Klump,-J.V.; Sager,-P.; Edgington,-D.N.
AF: Cent. Great Lakes Stud., Univ. Wisconsin, Milwaukee, WI, USA
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 63
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: The tributaries of Green Bay, primarily the lower Fox River, have long recognized as major sources of phosphorus in the Lake Michigan basin. The status of Green Bay as a sink or source of phosphorus for Lake Michigan proper has been less well defined. Data on external phosphorus loading to the bay are examined in relation to sediment fluxes of phosphorus in the bay to arrive at a simple model of the phosphorus budget for Green Bay. Tributary loadings are estimated at more than 660,000 kg/y, 75% of which is from the Fox River. At least 50% of the Fox River load in turn originates in the upper watershed above Lake Winnebago, significantly broadening the area of concern for phosphorus control. Sediment flux data leave a substantial portion of the phosphorus load unaccounted for in the southern half of the bay, requiring that either northern Green Bay or Lake Michigan is a significant phosphorus sink.
AN: 3719186
380 of 1521
TI: Mechanisms controlling primary production in Lake Michigan
AU: Brooks,-A.S.; Edgington,-D.N.
AF: Dep. Biol. Sci., Geosci. Cent. Great Lakes Stud., Univ. Wisconsin, Milwaukee, WI, USA
CO: 36. Conf. of the Int. Association for Great Lakes Research, De Pere, WI (USA), 4-10 Jun 1993
SO: OME-36TH-CONFERENCE-OF-THE-INTERNATIONAL-ASSOCIATION-FOR-GREAT-LAKES-RESEARCH,-JUNE-4-10,-1993.-PROGRAM-AND-ABSTRACTS. 1993 p. 36
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: A three-year study, 1986-1988, has revealed a biogeochemical, climatically-coupled mechanism controlling spring primary production in Lake Michigan. The mass of total phosphorus in the water increases from 1.3 to 3.5 mu mole-P cm in concert with increases in chlorophyll-a and organic nitrogen and decreases in nitrate and soluble Si. During spring, solar irradiance, wind-driven mixing and the onset of thermal stratification determine the magnitude of the spring bloom. The rate of production is determined by the geochemical flux of P from the sediments to the overlying water. The sequestration of P by the primary producers displaces the geochemical equilibrium, which allows more P to be released from the sediments to the water. Primary production measurements made in Lake Michigan will be compared with those in Lake Ontario.
AN: 3719091
381 of 1521
TI: Microbial community structure at the U.S.-Joint Global Ocean Flux study station ALOHA: Inverse methods for estimating biochemical indicator ratios
AU: Christian,-J.R.; Karl,-D.M.
AF: Sch. Ocean and Earth Sci. and Technol., Univ. Hawaii at Manoa, Honolulu, HI 96822, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1994 vol. 99, no. C7, pp. 14,269-14,276
LA: English
ER: M (Marine)
AB: Modeling biogeochemical fluxes in the marine plankton requires the application of factors for extrapolation of biomass indicators measured in the field (chlorophyll a, adenosine triphosphate, bacterial counts) to biomass carbon or nitrogen. These are often inferred from culture studies and are poorly constrained for natural populations. A least squares inverse method with a simple linear model constrains the values of several common indicator ratios, giving self-consistent solutions that provide useful information about the structure of the microbial community at our North Pacific Ocean study site (Station ALOHA (A Long-term Oligotrophic Habitat Assessment)). These results indicate that the fraction of the microbial biomass that is autotrophic (pigmented) is greater in the mixed layer than at the deep chlorophyll maximum layer and that heterotrophic bacteria are a significant but not necessarily predominant component of the microbial community in the euphotic zone.
AN: 3718044
382 of 1521
TI: Physical processes affecting availability of dissolved silicate for diatom production in the Arabian Sea
AU: Young,-D.K.; Kindle,-J.C.
AF: Oceanogr. Div. Nav. Res. Lab., Stennis Space Cent., MS, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1994 vol. 99, no. C11, pp. 22,619-22,632
LA: English
ER: M (Marine)
AB: A passive tracer to represent dissolved silicate concentrations, with biologically realistic uptake kinetics, is successfully incorporated into a three-dimensional, eddy-resolving, ocean circulation model of the Indian Ocean. Hypotheses are tested to evaluate physical processes which potentially affect the availability of silicate for diatom production in the Arabian Sea. An alternative mechanism is offered to the idea that open ocean upwelling is primarily responsible for the high, vertical nutrient flux and consequent large-scale phytoplankton bloom in the northwestern Arabian Sea during the southwest monsoon. Model results show that dissolved silicate in surface waters available for uptake by diatoms is primarily influenced by the intensity of nearshore upwelling from southwest monsoonal wind forcing and by the offshore advective transport of surface waters. The absence of diatoms in sediments of the eastern Arabian Basin is consistent with modeled distributional patterns of dissolved silicate resulting from limited westward advection of upwelled coastal waters from the western continental margin of India and rapid uptake of available silicate by diatoms.
AN: 3717689
383 of 1521
TI: Particle-associated PCBs in Lake Ontario
AU: Mudroch,-A.; Kaiser,-K.L.E.; Comba,-M.E.; Neilson,-M.
AF: Lakes Res. Branch, Natl. Water Res. Inst., Burlington, ON L7R 4A6, Canada
SO: SCI.-TOTAL-ENVIRON. 1994 vol. 158, pp. 113-125
LA: English
ER: F (Freshwater)
AB: A study was carried out to evaluate the role of the nepheloid layer in the transport and cycling of PCBs in Lake Ontario in 1987-89 and 1991. Water, suspended matter, and bottom sediment samples were collected at eleven stations in Lake Ontario. The concentrations of t-PCBs in the suspended matter in the nepheloid layer ranged from 151 to 728 ng/g (dry wt) in 1987-1989, and were greater than those in most of the top 3-cm sediments (< 1-405 ng/g dry wt). The suspended matter in the nepheloid layer contained more lower chlorinated biphenyls, particularly tetra- and pentachlorobiphenyls, than the bottom sediments. The greatest concentrations (up to 4100 ng/g dry wt) existed in the suspended matter at 15 m above the lake bottom after the development of the nepheloid layer. The results of the study indicated the association of t-PCBs with allochthonous particles originating mainly during the summer months in the surface water which were sinking through the water column and accumulated in the nepheloid layer in late August and September.
AN: 3717607
384 of 1521
TI: Development and field validation of a microcosm to simulate the mercury cycle in a contaminated pond
AU: Saouter,-E.; Gillman,-M.; Turner,-R.; Barkay,-T.*
AF: U.S. EPA, Environ. Res. Lab., 1 Sabine Island Dr., Gulf Breeze, FL 32561, USA
SO: ENVIRON.-TOXICOL.-CHEM. 1995 vol. 14, no. 1, pp. 69-77
LA: English
ER: F (Freshwater)
AB: A microcosm consisting of water, sediment, and air compartments was used to simulate mercury geochemical cycling in a mercury-contaminated ( mu g/L) pond at Oak Ridge, Tennessee. Total and dissolved mercury and total methylmercury were analyzed in water and sediment; total gaseous mercury and head-space mercury were analyzed in the water and head space, respectively. The production of gaseous mercury was correlated to dissolved mercury (0.2- mu m filtration), and methyl-mercury was mainly produced in the sediment compartment. Addition of mercuric chloride to the system increased the production of head-space mercury by a factor of 10 but did not affect the methylation rate. Saturation of gaseous mercury in microcosm water varied from 480 to 1,500% of the solubility of elemental mercury and was controlled by unidentified factors. The microcosm maintained stable conditions for up to 3 weeks, and a mass balance indicated that it reasonably simulated the cycling of mercury in the pond. This microcosm could be used to test remedial treatments aimed at decreasing the amount of mercury that is available for accumulation by biota.
AN: 3715076
385 of 1521
TI: Concentration and transport of nitrate by the mat-forming sulphur bacterium Thioploca
AU: Fossing,-H.; Gallardo,-V.A.; Joergensen,-B.B.; Huettel,-M.; Nielsen,-L.P.; Schulz,-H.; Canfield,-D.E.; Forster,-S.; Glud,-R.N.; Gundersen,-J.K.; Kuever,-J.; Ramsing,-N.B.; Teske,-A.; Thamdrup,-B.; Ulloa,-O.
AF: Max Planck Inst. Mar. Microbiol., Fahrenheitstr. 1, D-28359 Bremen, FRG
SO: NATURE 1995 vol. 374, no. 6524, pp. 713-715
LA: English
ER: M (Marine)
AB: Marine species of Thioploca occur over 3,000 km along the continental shelf off Southern Peru and North and Central Chile. These filamentous bacteria live in bundles surrounded by a common sheath and form thick mats on the sea floor under the oxygen-minimum zone in the upwelling region, at between 40 and 280 m water depth. The metabolism of this marine bacterium remained a mystery until long after its discovery. We report here that Thioploca cells are able to concentrate nitrate to up to 500 mM in a liquid vacuole that occupies > 80% of the cell volume. Gliding filaments transport this nitrate 5-10 cm down into the sediment and reduce it, with concomitant oxidation of hydrogen sulphide, thereby coupling the nitrogen and sulphur cycles in the sediment.
AN: 3714388
386 of 1521
TI: Biogeochemical processes of the sulphur cycle at early stages of sediment diagenesis along the Enisei River--Kara Sea profile.
OT: Biogeokhimicheskie protsessy tsikla sery na rannikh stadiyakh diageneza osadkov na profile reka Enisej--Karskoe more
AU: Lein,-A.Yu.; Miller,-Yu.M.; Namsaraev,-B.B.; Pavlova,-G.A.; Pimenov,-N.V.; Rusanov,-I.I.; Savvichev,-A.S.; Ivanov,-M.V.
AF: Inst. Geokhim. Anal. Khim. RAN, Moscow, Russia
SO: OKEANOLOGIYA 1994 vol. 34, no. 5, pp. 681-692
LA: Russian
ER: M (Marine); F (Freshwater)
AB: The paper presents data on the chemical composition of pore water, content of different sulphur compounds, their isotope composition and the rate of sulphate reduction in sediment samples collected during the 49th cruise of the R/V Dmitrij Mendeleev in August-September 1993. The rate of sulphate reduction in the profile sediments was found to differ by an order of magnitude. It is at a maximum (1.5 mg S/kg day) and comparable to that in the shallow water sediments from the North Sea in the Enisei delta deposits and in the northern part of the profile. The sediments from the river offing show much lower rates of bacterial sulphate reduction (0.03-0.06 mg S/kg day). The annual production of reduced sulphur in the sediments is estimated at 24 times 10 super(6) tons and only 2% of this amount is buried. The annual expenditure of organic carbon for sulphate reduction in the Enisei mouth zone is 17.6 times 10 super(6) tons.
AN: 3714383
387 of 1521
TI: A high-resolution Sr/Ca and delta super(18)O coral record from the Great Barrier Reef, Australia, and the 1982-1983 El Nino
AU: McCulloch,-M.T.; Gagan,-M.K.; Mortimer,-G.E.; Chivas,-A.R.; Isdale,-P.J.
AF: Res. Sch. Earth Sci., Australian Natl. Univ., Canberra, A.C.T. 0200, Australia
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 12, pp. 2747-2754
LA: English
ER: M (Marine)
AB: A high-resolution (near weekly) Sr/Ca and oxygen isotopic record is presented for a coral from the Pandora Reef in the Great Barrier Reef (GBR) of Australia during the period 1978 to 1984. The records are well correlated except for periods of high rainfall when river runoff has significantly modified the delta super(18)O value of seawater. Using the Sr/Ca temperature calibration of De Villiers et al. (1994), the Sr/Ca records exhibit seasonally controlled cyclical SST (sea surface temperature) variations of from similar to 21 to similar to 28 degree C. During the very strong El Nino of 1982-1983, the Sr/Ca systematics indicate a sharp drop in the winter SST to similar to 18.5 degree C. Due to the extremely low ( similar to 10 super(-3)) Sr and Ca contents of river runoff relative to seawater, it is possible to use the Sr/Ca thermometer to calculate temperatures independent of major floods and hence deconvolve the combined effects in the oxygen isotopic record of variable temperature and the delta super(18)O value of seawater. Using this approach it is possible to quantitatively reproduce the volume of runoff from the Burdekin River during the periods of major flooding that occurred in early 1979 and 1981. The results of this study demonstrate that the combined use of high-resolution Sr/Ca and delta super(18)O systematics in scleractinian corals is a powerful tool for providing quantitative constraints on past climate.
AN: 3714331
388 of 1521
TI: Carbon isotope variations in a solar pond microbial mat: Role of environmental gradients as steering variables
AU: Schidlowski,-M.; Gorzawski,-H.; Dor,-I.
AF: Max-Planck-Inst. Chem., Saarstr. 23, D-55020 Mainz, FRG
SO: GEOCHIM.-COSMOCHIM.-ACTA 1994 vol. 58, no. 10, pp. 2289-2298
LA: English
ER: M (Marine)
AB: A biogeochemical traverse is presented for a juvenile benthic mat covering the depth profile of an artificially stratified and eutrophicated hypersaline heliothermal pond with known gradients of temperature, salinity, pH, and light transmission. It can be shown that visual mat development depends primarily on temperature and salinity as main environmental steering variables whose increase with depth goes along with the attenuation and final disappearance of a visible microbial film in the pond's hypolimnic compartment. Recorded biogeochemical parameters (C sub(org) content, cell numbers, chlorophyll-a content) evidently reflect, as either biomass- or productivity-related index functions, the visually perceptible growth gradient of the microbial ecosystem along the pond slope. The observed coincidence of maxima in these index functions with maxima in delta super(13)C sub(org) identifies high rates of primary productivity as the agent ultimately responsible for the generation of super(13)C-enriched biomass in these and related environments.
AN: 3714294
389 of 1521
TI: Mangroves as filters of shrimp pond effluent: Predictions and biogeochemical research needs
AU: Robertson,-A.I.; Phillips,-M.J.
AF: Australian Inst. Mar. Sci., PMB No. 3, Townsville MC, Qld. 4810, Australia
CO: Asia-Pacific Symposium on Mangrove Ecosystems, (Hong Kong), 1-3 Sep 1993
SO: PROCEEDINGS-OF-THE-ASIA-PACIFIC-SYMPOSIUM-ON-MANGROVE-ECOSYSTEMS. Wong,-Yuk-Shan;Tam,-N.F.Y.-eds. 1995 vol. 295, no. 1-3 pp. 311-321
ST: HYDROBIOLOGIA vol. 295, no. 1-3
LA: English
ER: M (Marine); B (Brackish)
AB: Preliminary estimates of the ratio of mangrove forest:shrimp pond area necessary to remove nutrients from shrimp pond effluent are made using budgets of nitrogen and phosphorus output for semi-intensive and intensive shrimp ponds combined with estimates of total net primary production in Rhizophora-dominated mangrove forests in tropical coastal areas. If effluent is delivered directly to mangrove forest plots, it is estimated that, depending on shrimp pond management, between 2 and 22 hectares of forest are required to filter the nitrogen and phosphorus loads from effluent produced by a 1 hectare pond. While such ratios may apply to small scale, integrated shrimp aquaculture-mangrove forestry farming systems, the variability in mangrove hydrodynamics makes it difficult to apply such ratios at a regional scale. Before mangroves can be used to strip shrimp pond effluent more research is required on the effects that high ammonia and particulate organic matter loads in pond effluent have on nutrient transformations in mangrove sediments and on forest growth.
AN: 3714239
390 of 1521
TI: Temporary and definitive fixation of atmospheric lead in deep-sea sediments of the western Mediterranean Sea
AU: Fernex,-F.; Migon,-C.
AF: Lab. Geodyn. Sous-Mar., CNRS U.A. 132 Geosci. Environ., La Darse, BP 48, F-06230 Villefranche-sur-Mer, France
SO: MAR.-POLLUT.-BULL. 1994 vol. 28, no. 12, pp. 727-734
LA: English
ER: M (Marine)
AB: Most lead brought to the Mediterranean Sea has an anthropogenic origin and is mainly transported through the atmosphere. Atmospheric Pb was continuously collected at Cap Ferrat in 1986 and 1987. From this study, the estimation of the anthropogenic Pb flux on the whole Western Mediterranean was, averaged on 1986 and 1987 data, 4080 t. Assuming that the atmospheric anthropogenic Pb input varied in this course of time similarly to the consumption of Pb added to gasolines in France, the mean annual flux could be calculated: 3.95 kg/km super(2)/yr, that is an annual input of 3360 t/yr. Reaching the sea, this metal seems to become rapidly bound to phytoplankton. Grazing by zooplankton leads to the production of faecal pellets which frequently contain rather high metal concentrations. The sinking rate of pellets of various zooplankton species is high; within a few days pellets may reach deep-sea sediments. After deposition, Pb is released from this organic-rich material during early diagenesis. In most cases, it, therefore, returns to the overlaying water body by ascending diffusion. But, in a deep-sea area of approximately 80 000 km super(2) where Mn oxide precipitation occurs in surficial sediments, Pb seems to remain stored by coprecipitation processes. By considering the lead stored in 'excess' in the surficial sediment of the deep-sea area, we estimate that a mean annual anthropogenic Pb amount ranging from 800 up to 1080 t was stored every year from 1950. On the same area, taking into account the Pb loss at the straits, the 'direct' atmospheric input to the sea bottom is, on average, 184 t/yr. The remaining part, that is (800-1080)-184 = (616-896) t/yr, corresponds to an additional 'indirect' Pb flux in water due to Pb released from sediments of the surrounding areas where it does not remain stored.
AN: 3713049
391 of 1521
TI: Activity of methanotrophic bacteria in Green Bay sediments
AU: Buchholz,-L.A.; Klump,-J.V.; Collins,-M.L.P.; Brantner,-C.A.; Remsen,-C.C.*
AF: Cent. Great Lakes Stud., Univ. Wisconsin, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA
SO: FEMS-MICROBIOL.-ECOL. 1995 vol. 16, no. 1, pp. 1-8
LA: English
ER: F (Freshwater)
AB: Sediment pore water samples obtained from a 19 m station in Green Bay in Lake Michigan were examined for levels of ambient dissolved methane and copper, and for the potential for in situ methane oxidation by methanotrophs found within surface sediments. The in situ methane concentration in the upper oxic sediment layer ranged from 20-150 mu mol/l at this station. The activity of methanotrophs and the kinetics of methane oxidation in these sediments were demonstrated by the uptake of radiolabeled methane. K sub(s) values varied between 4.1-9.6 nmol/cm super(3) of sediment slurry. High V sub(max) values (12.7-35.2 nmol/cm super(3)/h) suggest a large population of methanotrophs in the sediments. An average methane flux to the oxic sediments of 0.24 mol/m super(2)/year was calculated from the pore water methane gradients. Pore water concentrations of copper in the upper sediment layer ranged from 10-120 nmol/l. Based upon the copper concentration, other measured parameters, and equilibrium conditions defined by WATEQF4, an estimate for dissolved free Cu super(2+) concentration of 5-38 nmol/l pore water was obtained. Several factors control the rate of methane oxidation, including oxygen, methane, and the bioavailability of free Cu super(2+).
AN: 3712971
392 of 1521
TI: The silica balance in the world ocean: A reestimate
AU: Treguer,-P.; Nelson,-D.M.; Van-Bennekom,-A.J.; DeMaster,-D.J.; Leynaert,-A.; Queguiner,-B.
AF: URA, CNRS 1513, Inst. Univ. Bretagne Occidentale, 6 Ave. Le Gorgeu, BP 809, F-29285 Brest Cedex, France
SO: SCIENCE-WASH. 1995 vol. 268, no. 5209, pp. 375-379
LA: English
ER: M (Marine)
AB: The net inputs of silicic acid (dissolved silica) to the world ocean have been revised to 6.1 plus or minus 2.0 teramoles of silicon per year (1 teramole = 10 super(12) moles). The major contribution (about 80 percent) comes from rivers, whose world average silicic acid concentration is 150 micromolar. These inputs are reasonably balanced by the net ouputs of biogenic silica aof 7.1 plus or minus 1.8 teramoles of silicon per year in modern marine sediments. The gross production of biogenic silica (the transformation of dissolved silicate to particulate skeletal material) in surface waters was estimated to be 240 plus or minus 40 teramoles of silicon per year, and the preservation ratio (opal accumulation in sediment/gross production in surface waters) averages 3 percent. In the world ocean the residence time of silicon, relative to total biological uptake in surface waters, is about 400 years.
AN: 3711989
393 of 1521
TI: Maldanid polychaetes as vehicles for rapid subduction of phytodetritus on the North Carolina slope
AU: Levin,-L.; Blair,-N.; Plaia,-G.; DeMaster,-D.; Martin,-C.; Fornes,-W.
AF: Scripps Inst. Oceanogr., La Jolla, CA 92093-0218, USA
CO: 23. Benthic Ecology Meeting, New Brunswick, NJ (USA), 17-19 Mar 1995
SO: TWENTY-THIRD-BENTHIC-ECOLOGY-MEETING. Grassle,-J.P.;Kelsey,-A.;Oates,-E.;Snelgrove,-P.V.-eds. Rutgers-the-State-Univ.,-New-Brunswick,-NJ-USA.-Inst.-Marine-Coastal-Sciences 1995 vp
NT: Abstract only.
LA: English
ER: M (Marine)
AB: Maldanids, which often live head down, are typically considered to be conveyor belt feeders that transport deposits from deep in the sediment column to the sediment surface. However hoeing of surface material has been described in at least one shallow water species (Dobbs and Whitlatch 1982). We have observed rapid subduction of an experimentally-placed tracer mixture containing super(13)C-labeled diatoms Thalassiosira pseudonona, kaolinite clay, glass beads and super(113)Sn-labeled slope sediments, by the maldanid Praxillella sp. at an 850-m site off Cape Hatteras, NC. After 1.5 da. material placed on the surface was observed at 10-13 cm depths in the sediment column near maldanid tube bases, in maldanid guts, and incorporated into maldanid tubes. Praxillella sp. occurs at densities of similar to 450 ind./m super(2) at our study site and maldnids are common in bathyal sediments throughout the world's oceans. Through surface feeding, caching, and tube construction, maldanids may cause significant vertical advection of labile carbon below the sediment surface, with important biogeochemical consequences.
AN: 3711690
394 of 1521
TI: Nitrogen fixation and photosynthesis in high arctic forms of Nostoc commune
AU: Lennihan,-R.; Chapin,-D.M.*; Dickson,-L.G.
AF: EA Eng., Sci. Technol., Inc., 8577 154th Ave. NE, Redmond, WA 98052, USA
SO: CAN.-J.-BOT.-REV.-CAN.-BOT. 1994 vol. 72, no. 7, pp. 940-945
LA: English
ER: F (Freshwater)
AB: Nostoc commune, a colonial cyanobacterium, has been suggested as an important contributor of nitrogen to terrestrial ecosystems in the Canadian High Arctic, yet little is known about the ecophysiology of this organism in arctic environments. This study focused on the physiological performance of macroscopic colonies of N. commune found on Devon Island, N.W.T. The objectives were to examine the influence of temperature, colony morphology, and seasonal phenology on nitrogen fixation rates and the effects of light and temperature on photosynthesis. Maximum rates of acetylene reduction in N. commune (2119 nmol C sub(2)H sub(4)/g/h) were higher than those previously recorded for arctic N. commune but lower than values reported for temperate populations. Depending on the time of the growing season, the temperature optimum for acetylene reduction varied from 15 degree C to greater than 20 degree C. Photosynthetic temperature optima did not occur below 20-25 degree C (the highest temperatures measured). Light saturation of photosynthesis was reached at low levels of irradiance (100-150 mu mol/m super(2)/s PPFD). Acetylene reduction rates varied strongly with colony morphology. Thin, fragile, flattened colonies had higher rates than thicker, more resilient, flattened colonies or spherical colonies. Cold post-thaw temperatures appeared to delay the recovery of maximum nitrogen fixation rates for 2-3 weeks following the onset of the growing season. Compared with two other species of cyanobacteria present on Truelove Lowland (Gloeocapsa alpina and Gleotrichia sp.), N. commune had higher rates of nitrogen fixation.
AN: 3711655
395 of 1521
TI: A comparison of sites in the EXMAN project, with respect to atmospheric deposition and the chemical composition of the soil solution and foliage
AU: Farrell,-E.P.; Cummins,-T.; Collins,-J.F.; Beier,-C.; Blanck,-K.; Bredemeier,-M.; De-Visser,-P.H.B.; Kreutzer,-K.; Rasmussen,-L.; Rothe,-A.; et-al.
AF: Dep. Environ. Resour. Manage., University Coll. Dublin, Eire
CO: Symposium on Experimental Manipulations of Biota and Biogeochemcial Cycling in Ecosystems, Copenhagen (Denmark), May 1992
SO: FOR.-ECOL.-MANAGE. 1994 vol. 68, no. 1, pp. 3-14
LA: English
AB: Forest stands, throughfall and the composition of the soil solution in six coniferous forest plantations in Europe were compared as part of the EXMAN project, which was established to quantify biogeochemical cycles and the effects of atmospheric deposition on coniferous forest ecosystems. Even though the EXMAN stands and sites are broadly similar, they represent a wide range of climatic conditions and levels of pollutant deposition. The EXMAN project incorporates treatment of forest plots and in this paper the untreated control plots are compared. The results show marked differences in ionic composition of water between sites, most clearly expressed in throughfall fluxes. At the German and Dutch sites, ionic inputs demonstrate a strong human influence. Throughfall at the Danish and Irish sites is dominated by ions of marine origin. Hydrogen ions are not the most important cations in precipitation at any site, and at only one site (Solling, Germany) was the hydrogen ion flux in throughfall greater than in precipitation. The influence of atmospheric deposition on the composition of the soil water is very evident for most major ions. Exceptions to this are ammonium and nitrate, the complexity of whose behaviour demonstrates the need for greater understanding of nitrogen transformation and uptake in coniferous forest ecosystems.
AN: 3710645
396 of 1521
TI: Measurements of the total CO sub(2) concentration and partial pressure of CO sub(2) in seawater during WOCE expeditions in the South Pacific Ocean. Progress report, (January 1, 1993--December 31, 1993)
AU: Takahashi,-T.; Goddard,-J.G.; Chipman,-D.W.; Rubin,-S.I.
CA: Lamont-Doherty Earth Observatory, Palisades, NY (USA)
SO: 1993 14 pp
NT: NTIS Order No.: DE93018158XSP.
RN: ID No: DOEER615391 (NoDOEER615391)
LA: English
ER: M (Marine)
AB: During the first year of the grant, we participated in three WOCE expeditions (a total of 152 days at sea) in the South Pacific Ocean, and the field phase of the proposed investigation has been successfully completed. The total CO sub(2) concentration and pCO sub(2) were determined at sea in 4419 water samples collected at 422 stations. On the basis of the shipboard analyses of SIO Reference Solutions for CO, and a comparison with the results of previous expeditions, the overall precision of our total CO sub(2) determinations is estimated to be about +2 mu M/kg. The deep water data indicate that there is a CO sub(2) maximum centered about 2600 meters deep. This appears to represent a southward return flow from the North Pacific. The magnitude and distribution of the CO, maximum observed along the 135.0 degree W meridian differ from those observed along the 150.5 degree W meridian due to Tuamotu Archipelago, a topographic high which interferes with the southward return flow. The surface water pCO sub(2) data indicate that the South Pacific sub-tropical gyre water located between about 15 degree S and 50 degree S is a sink for atmospheric CO sub(2).
AN: 3708404
397 of 1521
TI: Inuit exposure to organochlorines through the aquatic food chain in Arctic Quebec
AU: Dewailly,-E.; Ayotte,-P.; Bruneau,-S.; Laliberte,-C.; Muir,-D.C.G.; Norstrom,-R.J.*
AF: Environ. Health Serv., Public Health Cent. (Quebec Reg.)-CHUL, 2050 Blvd. Rene-Levesque, Ste-Foy, PQ G1V 2K8, Canada
SO: ENVIRON.-HEALTH-PERSPECT. 1993 vol. 101, no. 7, pp. 618-620
LA: English
AB: Inuit people (Eskimos) are likely exposed to persistent organochlorine compounds because their traditional diet includes fatty tissues of the arctic marine biota. Here we present the results of organochlorine compound analysis in milk fat samples from arctic Quebec Inuit women and in fat tissues from various animal species inhabiting that region. The total concentration of polychlorinated biphenyl congeners in Inuit milk fat was similar to that of the beluga, while the profile of the 10 congeners resembled that of the polar bear. Mean concentrations of various organochlorines in milk-fat samples from Inuit women were between 2 and 10 times greater than those found in samples previously collected from southern Quebec women. The Inuit mothers exhibit the greatest body burden known to occur from exposure to organochlorine residues present in the environment by virtue of their location at the highest trophic level of the arctic food web.
AN: 3708370
398 of 1521
TI: Freshwater sediments: Sinks and sources of bromine
AU: Song,-Y.; Mueller,-G.
AF: Inst. Sedimentforschung der Univ., D-69020 Heidelberg, FRG
SO: NATURWISSENSCHAFTEN 1993 vol. 80, no. 12, pp. 558-560
LA: English
ER: F (Freshwater)
AB: With 2.5 mg/kg in crustal rocks bromine is forty-sixth in order of abundance. Like chlorine, the largest natural sources of bromine are the oceans which contain 65 mg/l. Amongst salt lakes the Dead Sea is extremely enriched in bromine with concentrations exceeding 4000 mg/l. In contrast to seawater or water of saline lakes, bromine concentrations in freshwater rivers and lakes are extremely low: in 126 water samples from rivers in the inland area of Finland, bromine concentrations were in the range of 0.006-0.108 mg/l, similar concentrations (0.005-0.146 mg/l) were found in 25 rivers of the (former) USSR. The water of the Danube near Regensburg contained 0.013 mg/l, three small rivers entering the Soese water reservoir in the Harz mountains had Br concentrations between 0.008 and 0.020 mg/l. Within the framework of investigations of sediment/interstitial water interactions in freshwater sediments applying in-situ dialysis methods for the collection of pore water, locations in the Neckar river drainage area were studied.
AN: 3708330
399 of 1521
TI: Biogenic production and consumption of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in the marine epipelagic zone: A review
AU: Groene,-T.
AF: Environ. Inst. (TP 272), Joint Res. Cent., 21020 Ispra (Va), Italy
SO: J.-MAR.-SYST. 1995 vol. 6, no. 3, pp. 191-209
LA: English
ER: M (Marine)
AB: Dimethylsulfide (DMS) is the dominating sulfur gas in surface marine waters. The flux of DMS to the atmosphere plays an important role in the natural sulfur cycle and in the formation of acidic components and condensation nucleii in the remote oceanic atmosphere and is likely to be of climatic significance. This article reviews the biologic production and consumption processes of DMS and its precursor dimethylsulfoniopropionate (DMSP) in ocean surface waters. The description of relevant processes in this paper is complemented by rate estimates where such data are available. The literature on a region in the Northeast Atlantic Ocean is reviewed to provide information on DMS and DMSP pools in situ and their regional and seasonal variations.
AN: 3708251
400 of 1521
TI: Biogenic silica fluxes and accumulation rates in the Gulf of California
AU: Thunell,-R.C.; Pride,-C.J.; Tappa,-E.; Muller-Karger,-F.E.
AF: Dep. Geol. Sci., Univ. South Carolina, Columbia, SC 29208, USA
SO: GEOLOGY 1994 vol. 22, no. 4, pp. 303-306
LA: English
ER: M (Marine)
AB: The Gulf of California, though small in size, plays an important role in the global silica cycle. The seasonal pattern of biogenic silica flux in the gulf is closely related to that of phytoplankton biomass levels and is controlled by changes in weather and hydrographic conditions. The highest opal fluxes ( similar to 0.35 g/m super(2)/d) occur during winter and spring, and they are comparable to those measured in some of the most productive ecosystems of the world. Approximately 15%-25% of the biogenic silica produced in surface waters is preserved in gulf sediments, a figure significantly higher than the average global ocean preservation rate. However, the flux of opal at 500 m water depth is less than 25% of that being produced at the surface, suggesting that most of the recycling of biogenic silica in the Gulf of California occurs in the upper water column.
AN: 3705681
401 of 1521
TI: Original mineralogy of carboniferous worm tubes: Evidence for changing marine chemistry and biomineralization: Comment and reply
AU: Weedon,-M.J.; Taylor,-P.D.
AF: Dep. Palaeontol., Nat. Hist. Mus., London SW7 5BD, UK
SO: GEOLOGY 1994 vol. 22, no. 3, pp. 281-282
LA: English
ER: M (Marine)
AB: In a stimulating paper, Railsback (1993) claimed that serpulid tube mineralogy changed from calcitic in the Mississippian to aragonitic in the Pennsylvanian, concluding that this change (1) supported evidence from abiotic carbonates that marine chemistry underwent a significant change at the end of the Mississippian; (2) illustrated the susceptibility of biologically induced biomineralization to long-term environmental change; and (3) raised the possibility that similar mineralogical changes might be found in other organisms in response to changing marine chemistry. However, several criticisms cast doubt on these three conclusions. The putative change from calcitic serpulids in the Mississippian to aragonitic serpulids in the Pennsylvanian obviously depends upon all of the studied fossils being identified correctly as serpulids which belong to an evolutionary lineage or at least the same taxonomic group. Neither of these essential prerequisites is convincingly demonstrated in the paper.
AN: 3705649
402 of 1521
TI: Effects of agricultural development on processing of tussock leaf litter in high country New Zealand streams
AU: Young,-R.G.; Huryn,-A.D.; Townsend,-C.R.
AF: Dep. Zool., Univ. Otago, P.O. Box 56 Dunedin, New Zealand
SO: FRESHWAT.-FORUM 1994 vol. 32, no. 2, pp. 413-427
LA: English
ER: F (Freshwater)
AB: The authors compare the rates and mechanisms of processing of tussock (Chionochloa spp.) leaf litter in six New Zealand streams draining grassland catchments that contrast in the extent to which they have been developed for pasture. Rates of processing, measured as rate of weight loss of leaf packs and rate of leaf softening, were at the slow end of the spectrum for vascular plant processing. Processing was faster at developed sites, mediated mainly through the influence of oxidized nitrogen concentration on microbial activity. Few invertebrate shredders colonized leaf packs and it is unlikely that invertebrates had an appreciable effect on leaf processing in our study streams, which do not effectively retain leaf litter. Very small headwater tributaries appear to retain leaf litter and possess a more abundant shredder community. The authors discuss the potential for using rate of leaf litter processing as a method of bioassessment.
AN: 3705235
403 of 1521
TI: Assessment of the eutrophication of Al Massira Reservoir (Morocco) by means of a survey of the biogeochemical balance of phosphate
AU: Alaoui-Mhamdi,-M.; Aleya,-L.*
AF: Lab. Zool. Protistol., URA CNRS 138 Aubiere Cedex, France
SO: HYDROBIOLOGIA 1995 vol. 297, no. 1, pp. 75-82
NT: Special issue: Sediment-water Interaction 5.
LA: English
ER: F (Freshwater)
AB: The biogeochemical balance of phosphate was studied in Al Massira reservoir (Morocco) from February 1991 to end January 1992. The study concerned P-supplies and losses by the Oum errbia river, sedimentation rate and water-sediment exchange. Supply and loss of phosphate were calculated from samples collected every 48 hours. Phosphate sedimentation rate was measured with sediment traps. The assessment of phosphate release at the water-sediment interface during either low oxic or anoxic conditions was made in situ with a benthic chamber. The results showed that phosphate input was higher than phosphate output resulting in a progressive increase of the internal phosphorus stock. The sedimentation flux ranged between 9 and 19 mg/m super(2)/d of P. Release of phosphate depended on the oxygen concentration in the water. We suggest that a drastic control of phosphate input into the water must be achieved through a programmed of dephosphorylation of the tributaries to avoid accumulation of calcium-bound phosphate which may become a source of upward release of bioavailable phosphate. Further investigations of this flux should be carried out to check the quantitative influence on phytoplankton community dynamics.
AN: 3704320
404 of 1521
TI: A bloom of Dunaliella parva in the Dead Sea in 1992: Biological and biogeochemical aspects
AU: Oren,-A.; Gurevich,-P.; Anati,-D.A.; Barkan,-E.; Luz,-B.
AF: Div. Microb. Mol. Ecol., Alexander Silberman Inst. Life Sci., Hebrew Univ. Jerusalem, 91904 Jerusalem, Israel
SO: HYDROBIOLOGIA 1995 vol. 297, no. 3, pp. 173-185
LA: English
ER: B (Brackish)
AB: A bloom of the unicellular green alga Dunaliella parva (up to 15 000 cells/ml) developed in the upper 5 m of the water column of the Dead Sea in May-June 1992. This was the first mass development of Dunaliella observed in the lake since 1980, when another bloom was reported (up to 8800 cells/ml). For a bloom of Dunaliella to develop in the Dead Sea, two conditions must be fulfilled: the salinity of the upper water layers must become sufficiently low as a result of dilution with rain floods, and phosphate must be available. During the period 1983-1991 the lake was holomictic, hardly any dilution with rainwater occurred, and no Dunaliella cells were observed. Heavy rain floods in the winter of 1991-1992 caused a new stratification, in which the upper 5 m of the water column became diluted to about 70% of their former salinity. Measurements of the isotopic composition of inorganic carbon in the upper water layer during the bloom ( delta super(13)C = 5.1ppt) indicate a strong fractionation when compared with the estimated -3.4ppt prior to the bloom. The particulate organic carbon formed was highly enriched in light carbon isotopes ( delta super(13)C = -13.5ppt). The algal bloom rapidly declined during the months June-July, probably as a result of the formation of resting stages, which sank to the bottom. A smaller secondary bloom (up to 1850 cells/ml) developed between 6 and 10 m depth at the end of the summer. Salinity values at this deep chlorophyll maximum were much beyond those conductive for the growth of Dunaliella, and the factors responsible for the development of this bloom are still unclear.
AN: 3704319
405 of 1521
TI: Application of organic carbon and nitrogen stable isotope and C/N ratios as source indicators of organic matter provenance in estuarine systems: Evidence from the Tay Estuary, Scotland
AU: Thornton,-S.F.; McManus,-J.
AF: Sch. Earth Sci., Univ., Birmingham B15 2TT, UK
SO: ESTUAR.-COAST.-SHELF-SCI. 1994 vol. 38, no. 3, pp. 219-233
LA: English
ER: B (Brackish)
AB: The source of particulate organic matter (POM) in lacustrine and estuarine sediments from the Tay River catchment has been evaluated using stable carbon and nitrogen isotope and elemental C/N ratios. The delta super(13)C, delta super(15)N and C/N compositions of POM from the two environments were statistically distinct, enabling, by use of a simple two component mixing equation, assessment of the ability of each tracer to estimate the terrigenous flux to the estuarine organic matter pool. Estuarial mixing of terrigenous, indigenous estuarine and marine derived organics, recorded by delta super(13)C data, was only partly confirmed by equivalent delta super(15)N and C/N compositions which reflected greater control by organic matter diagenesis and biological processing. Limited data indicate sewage derived contributions are insignificant. Of the three tracers employed, only delta super(13)C ratios are reliable as provenance indicators. Both delta super(15)N and C/N ratios are limited because the original POM source signature may be lost or overprinted by biochemical alteration prior to and/or soon after deposition. The simultaneous application of these tracers provides substantially more information regarding the source, quality and turnover of sedimentary POM in these contrasting systems than could be achieved using one technique alone.
AN: 3704287
406 of 1521
TI: PCR for direct detection of indigenous uncultured magnetic cocci in sediment and phylogenetic analysis of amplified 16S ribosomal DNA
AU: Thornhill,-R.H.; Burgess,-J.G.; Matsunaga,-T.*
AF: Dep. Biotechnol., Tokyo Univ. Agric. and Technol., Koganei, Tokyo 184, Japan
SO: APPL.-ENVIRON.-MICROBIOL. 1995 vol. 61, no. 2, pp. 495-500
LA: English
ER: M (Marine)
AB: PCR primers specific to the 16S ribosomal DNA (rDNA) of magnetic cocci were designed and used to amplify DNA from magnetically isolated magnetic cocci. The PCR products were subcloned by ligation into plasmid vector pCRII, and five clones containing approximately 270-bp fragments of amplified DNA were sequenced. The specific primers were also used to detect magnetic coccus 16S rDNA in environmental samples. Magnetic coccus 16S rDNA was amplified from the water column above sediment kept in an anoxic environment in the laboratory, but little was amplified from a water column in an anoxic environment had migrated there from the sediment as a response to the microoxic or anoxic conditions, rather than having been present previously in a nonmagnetic form and having become magnetic due to these conditions. The specific primers were also used to detect magnetic cocci in aquatic sediment. DNA was extracted from sediment by direct lysis and purified for use as a PCR template by electrophoresis on an agarose-polyvinylpyrrolidone gel. 16S rDNA was then amplified and subcloned, and two clones were sequenced. The clones were screened for chimeric DNA by comparing sections of each with the GenBank database.
AN: 3704236
407 of 1521
TI: The stoichiometry of N and P in the pelagic zone of Castle Lake, California
AU: Elser,-J.J.; George,-N.B.
AF: Dep. Zool., Arizona State Univ., Tempe, AZ 85287, USA
SO: J.-PLANKTON-RES. 1993 vol. 15, no. 8, pp. 977-992
LA: English
ER: F (Freshwater)
AB: We measured the concentrations, as well as lake-wide amounts, of nitrogen (N) and phosphorus (P) in dissolved, seston and zooplankton pools throughout the water column of Castle Lake, California, during summer, 1991. This allowed us to determine the stoichiometric ratios of important elements in each pool (C:N, C:P, N:P) as well as for the entire lake. Dissolved and seston pools were the predominant storage compartments for both N and P; zooplankton never contained >5% of N or 10% of P lake wide. However, by late summer, the concentrations of P in seston and in zooplankton were similar in the upper portions of the water column, suggesting that changes in food web structure that alter zooplankton biomass and community composition (and hence elemental storage in the zooplankton) may produce significant shifts in nutrient storage among pelagic pools. Lake-wide levels of dissolved N were largely constant over the study period; however, lake-wide dissolved P increased. These dynamics suggested that the majority of nutrients stored in dissolved pools were unavailable for phytoplankton growth. N:P and C:P ratios indicated that Castle Lake phytoplankton became severely deficient in P during the course of our observations. These ratios also greatly exceeded recently reported threshold values for elemental constraints on growth and reproduction for several species of zooplankton. The ratio of N to P in the zooplankton pool was relatively constant and consistently lower than that in the sestion. As a result, the predicted N:P ratio of zooplankton-regenerated nutrients exceeded the N:P ratio of the seston, implying that zooplankton nutrient regeneration further skewed N and P supply ratios, and potentially enhanced P limitation of phytoplankton in Castle Lake.
AN: 3699797
408 of 1521
TI: The plankton multiplier -- positive feedback in the greenhouse
AU: Woods,-J.; Barkmann,-W.
AF: Nat. Environ. Res. Counc., Polaris House, Swindon SN2 1EU, UK
SO: J.-PLANKTON-RES. 1993 vol. 15, no. 9, pp. 1053-1074
LA: English
ER: M (Marine)
AB: The plankton multiplier is a positive feedback mechanism linking the greenhouse effect and biological pump. As pollution increases the atmospheric concentration of carbon dioxide, the enhanced greenhouse effect induces radiative forcing of the ocean, which diminishes the depth of winter convection, reducing the annual resupply of nutrients to the euphotic zone and therefore the annual primary production. That weakens the biological pump, which contributes to oceanic uptake of CO sub(2). As the ocean takes up less CO sub(2), more remains in the atmosphere, accelerating the rise in radiative forcing. We have used a mathematical model of the upper ocean ecosystem, based on the Lagrangian Ensemble method, to estimate the sensitivity of the biological pump to radiative forcing, which lies at the heart of the plankton multiplier. We conclude that increasing radiative forcing by 5 W m super(-2) (equivalent to doubling atmospheric CO sub(2)) reduces the deep flux of particulate carbon by 10%. That sensitivity is sufficient to produce significant positive feedback in the greenhouse. It means that the plankton multiplier will increase the rate of climate change in the 21st Century. It also suggests that the plankton multiplier is the mechanism linking the Milankovich effect to the enhanced greenhouse effect that produces global warming at the end of ice ages.
AN: 3699776
409 of 1521
TI: Biogeological mineralization in deep-sea hydrothermal deposits
AU: Cook,-T.L.; Stakes,-D.S.
AF: Monterey Bay Aquar. Res. Inst., 160 Central Ave., Pacific Grove, CA 93950, USA
SO: SCIENCE-WASH. 1995 vol. 267, no. 5206, pp. 1975-1979
LA: English
ER: M (Marine)
AB: Oriented drill cores retrieved from active massive sulfide edifices at the Endeavour Segment of the Juan de Fuca Ridge contain an abundance of fossilized tube structures associated with vestimentiferan and annelid worms. The petrological evolution of these biogeological structures and their presence deep inside the edifice walls demonstrate that an initial, worm-mediated texture directly affects the subsequent steps of inorganic precipitation, wall infilling, and outward growth of these black smoker deposits. The presence of fossilized structures in hydrothermal discharge sites that are 2 kilometers apart and their similarity to structures observed in other modern and ancient deposits suggest that these biogeological processes are general phenomena.
AN: 3699633
410 of 1521
TI: Biogeochemical cycles of carbon, sulfur, and free oxygen in a microbial mat
AU: Canfield,-D.E.; Des-Marais,-D.J.
AF: Sch. Earth Atmosp. Sci., Georgia Inst. Technol., Atlanta, GA 30332-0340, USA
SO: GEOCHIM.-COSMOCHIM.-ACTA 1993 vol. 57, no. 16, pp. 3971-3984
LA: English
ER: M (Marine); B (Brackish)
AB: Complete budgets for carbon and oxygen have been constructed for cyanobacterial mats dominated by Microcoleus chthonoplastes from the evaporating ponds of a salt works located in Guerrero Negro, Baja California Sur, Mexico. Included in the budget are measured rates of O sub(2) production, sulfate reduction, and elemental exchange across the mat/brine interface, day and night, at various temperatures and times of the year. We infer from this data the various sinks for O sub(2), as well as the sources of carbon for primary production. To summarize, although seasonal variability exists, a major percentage of the O sub(2) produced during the day did not diffuse out of the mat but was used within the mat to oxidize both organic carbon and the sulfide produced by sulfate production. At night, most of the O sub(2) that diffused into the mat was used to oxidize sulfide, with sub(2) respiration of minor importance. During the day, the internal mat processes of sulfate reduction and O sub(2) respiration generated as much or more inorganic carbon (DIC) for primary production as diffusion into the mat. Also, oxygenic photosynthesis was the most important process of carbon fixation, although anoxygenic photosynthesis may have been important at low light levels during some times of the year. At night, the DIC lost from the mat was mostly from sulfate reduction. Elemental fluxes across the mat/brine interface indicated that carbon with an oxidation state greater than zero was taken up by the mat during the day and liberated from the mat at night. Overall, carbon with an average oxidation state of near zero accumulated in the mat. Both carbon fixation and carbon oxidation rates varied with temperature by a similar amount. These mats are thus closely coupled systems where rapid rates of photosynthesis both require and fuel rapid rates of heterotrophic carbon oxidation.
AN: 3699462
411 of 1521
TI: The biogeochemistry of potassium at Hubbard Brook
AU: Likens,-G.E.; Driscoll,-C.T.; Buso,-D.C.; Siccama,-T.G.; Johnson,-C.E.; Lovett,-G.M.; Ryan,-D.F.; Fahey,-T.; Reiners,-W.A.
AF: Inst. Ecosyst. Stud., Millbrook, NY 12545, USA
SO: BIOGEOCHEMISTRY 1994 vol. 25, no. 2, pp. 61-125
LA: English
ER: F (Freshwater)
AB: A synthesis of the biogeochemistry of K was conducted during 1963-1992 in the reference and human-manipulated watershed-ecosystems of the Hubbard Brook Experimental Forest (HBEF), NH. Results showed that during the first two years of the study (1963-65), which coincided with a drought period, the reference watershed was a net sink for atmospheric inputs of K. During the remaining years, this watershed has been a net source of K for downstream ecosystems. There have been long-term declines in volume-weighted concentration and flux of K at the HBEF; however, this pattern appears to be controlled by the relatively large inputs during the initial drought years. Net ecosystem loss (atmospheric deposition minus stream outflow) showed an increasing trend of net loss, peaking during the mid-1970s and declining thereafter. This pattern of net K loss coincides with trends in the drainage efflux of SO sub(4) super(2-) and NO sub(3) super(-), indicating that concentrations of strong acid anions may be important controls of dissolved K loss from the site. There were no long-term trends in streamwater concentration or flux of K. A distinct pattern in pools and fluxes of K was evident based on biotic controls in the upper ecosystem strata (canopy, boles, forest floor) and abiotic controls in lower strata of the ecosystem (mineral soil, glacial till). Clearcutting disturbance resulted in large losses of K in stream water and from the removal of harvest products. Stream losses occur from release from slash, decomposition of soil organic matter and displacement from cation exchange sites. Elevated concentrations of K persist in stream water for many years after clearcutting. Of the major elements, K shows the slowest recovery from clearcutting disturbance.
AN: 3698183
412 of 1521
TI: Nutrient retention in riparian ecotones
AU: Vought,-L.B.-M.; Dahl,-J.; Pedersen,-C.L.; Lacoursiere,-J.O.
AF: Limnol., Dep. Ecol., Ecol. Build., Univ. Lund, S-223 62 Lund, Sweden
SO: AMBIO 1994 vol. 23, no. 6, pp. 342-348
LA: English
ER: F (Freshwater)
AB: Nutrient retention mechanisms in riparian buffer strips are reviewed with emphasis on surface runoff and subsurface flows, the main pathways of exchanges between the stream and its surroundings. Unique physical and biogeochemical properties prevailing in these riparian ecotones dictate the flux of water, nutrients and other exogenous substances between the upland areas and the stream. Removal of nutrients from surface inflows is induced by deposition of sediment bound nutrients and exchange of dissolved nutrients with the soil/litter surface. Removal of nitrogen in subsurface flows can partly be explained by vegetation uptake, but the main mechanism for removal is usually denitrification. In channelized streams, the subsurface inflows have, in most cases, been altered to discharges via drainage tiles, with the exchange flows (water leaving and re-entering the open-channel via the stream bed and banks) being greatly decreased. Consequently, to improve nitrogen removal in these systems, these flows have to be intercepted or reestablished either through restoration of the old stream valley or through managed structures in the buffer strips.
AN: 3697346
413 of 1521
TI: Nitrogen retention in forest wetlands
AU: Jacks,-G.; Joelsson,-A.; Fleischer,-S.
AF: Dep. Civ. and Environ. Eng., KTH, S-100 44 Stockholm, Sweden
SO: AMBIO 1994 vol. 23, no. 6, pp. 358-362
LA: English
ER: F (Freshwater)
AB: Forests in southern Sweden are receiving nitrogen depositions that are about twice the critical load. There are indications that nitrogen losses from forest land are increasing. Forest wetlands may in this perspective become important traps for nitrogen, thus, protecting streams, lakes and marine environments from eutrophication. A number of forest wetlands in southwestern Sweden have been investigated with the aim of assessing their efficiency as nitrogen traps. Nitrogen retention is small in undisturbed upland forest. However, increased nitrate flux from a clearcut area was largely retained in one of the studied wetlands. In the spruce, which is the dominating tree in southern Sweden, the large-scale damages due to soil acidification or climatic causes cannot be excluded and it is advocated that forest wetlands should not be subject to drainage.
AN: 3697345
414 of 1521
TI: Nitrogen retention in artificially flooded meadows
AU: Leonardson,-L.; Bengtsson,-L.; Davidsson,-T.; Persson,-T.; Emanuelsson,-U.
AF: Limnol., Dep. Ecol., Ecol. Build., S-223 62 Lund, Sweden
SO: AMBIO 1994 vol. 23, no. 6, pp. 332-341
LA: English
ER: F (Freshwater)
AB: Investigations of nitrogen retention in artificially flooded wetlands were performed in southern Sweden during 1991-1993. The purpose of the study was to investigate whether artificial flooding of meadows would be a possible means of reducing the nitrogen content in streams and rivers. Two case studies are presented, one from a sandy/organic soil, one from a peaty soil. Overall nitrogen retention was estimated by mass balance. Denitrification activity and plant biomass incorporation of nitrogen were used to complement and verify the mass-balance data. The study shows that artificial flooding of meadows did not contribute significantly to nitrogen retention in the introduced river water under the irrigation regimes utilized. The technique stimulated mineralization of the soil nitrogen pool to an extent which corresponded to the reduction of nitrate caused by denitrification. In the sandy/organic soil, denitrification was enhanced by the artificial flooding, while in the peat area the activity was lower than in a nonflooded reference area. Plant uptake of nitrogen was stimulated by flooding.
AN: 3697344
415 of 1521
TI: Stoichiometric nutrient balance and origin of coastal eutrophication
AU: Justic,-D.; Rabalais,-N.N.; Turner,-R.E.
AF: Coast. Ecol. Inst., Louisiana State Univ., Baton Rouge, LA 70803, USA
SO: MAR.-POLLUT.-BULL. 1995 vol. 30, no. 1, pp. 41-46
LA: English
ER: M (Marine)
AB: We present here an analysis of the stoichiometry of dissolved nutrients in 10 large world rivers, Amazon, Changjiang, Huanghe, Mackenzie, Mississippi, Po, Rhine, Seine, Yukon and Zaire, and in two river-dominated coastal ecosystems prone to eutrophication, the northern Adriatic Sea and the northern Gulf of Mexico. Our analysis suggests that proportions of dissolved silica (Si), nitrogen (N) and phosphorus (P) in rivers carrying nutrients of anthropogenic origin, as well as in the coastal waters strongly influenced by those rivers, have changed historically in a way that now closely approximates the Redfield ratio (Si:N:P=16:16:1). It is likely that coastal phytoplankton productivity has increased under these favourable nutrient conditions and was accompanied by an increasing incidence of noxious phytoplankton blooms and bottom water hypoxia.
AN: 3697313
416 of 1521
TI: Biochemical feedbacks in the oceanic carbon cycle
AU: Klepper,-O.; De-Haan,-B.J.; Van-Huet,-H.
AF: Natl. Inst. Public Health Environ. Prot., Cent. Math. Methods, P.O. Box 1, 3720 BA Bilthoven, Netherlands
CO: 8. Conference of the International Society for Ecological Modelling, Kiel (Germany), 28 Sep-2 Oct 1992
SO: ECOL.-MODEL. 1994 vol. 75-76, pp. 459-469
LA: English
ER: M (Marine)
AB: This paper presents the results of a coupled ocean circulation and biochemical model to study carbon uptake of the oceans by chemical buffering and primary production. The circulation model is a 2-dimensional model (latitudinally averaged per ocean basin with a 20 degree resolution, and 12 vertical layers). The biochemical model includes the elements C (as inorganic, particulate and dissolved organic), N, O, Ca and super(14)C, and models the fluxes between the various species (atmospheric exchange, physical transport, primary production, calcification, decomposition and dissolution). Steady-state results show good agreement with measurements. The model is then used in a sensitivity analysis to study the effect of possible changes in biochemical processes by running it to the year 2070 (projected atmospheric CO sub(2) doubling under "business as usual" scenario). It turns out that most of the feedbacks are positive, i.e.: ocean uptake capacity decreases more rapidly than in the simulation with constant process rates. As a result, atmospheric pCO sub(2) may rise considerably faster than is currently predicted using no-feedback ocean models.
AN: 3697117
417 of 1521
TI: Seasonal variability and biogeochemistry of phosphorus in the Scheldt Estuary, south-west Netherlands
AU: Zwolsman,-J.J.G.
AF: Delft Hydraul., P.O. Box 177, 2600 MH Delft, Netherlands
SO: ESTUAR.-COAST.-SHELF-SCI. 1994 vol. 39, no. 3, pp. 227-248
LA: English
ER: B (Brackish)
AB: The geochemistry of phosphate in the highly polluted Scheldt Estuary has been studied during eight cruises in 1987-88. Property-salinity plots show significant seasonal variability in the environmental conditions which trigger phosphate behaviour, such as dissolved oxygen, pH and phytoplankton activity. Consequently, the behaviour of orthophosphate differs from season to season. During autumn and winter, when phytoplankton activity is low or negligible, the orthophosphate profiles show the occurrence of a buffering mechanism, probably caused by desorption of particle-bound phosphorus in response to the increase in pH with increasing salinity. During spring and summer, the geochemistry of orthophosphate is influenced by the presence of anoxic headwaters. High phosphate concentrations are observed in the anoxic river water entering the estuary, probably reflecting release from the sediments. However, phosphate is rapidly removed from solution in the low-salinity zone due to co-precipitation with iron oxyhydroxides, formed by reoxidation in the water column. Seaward from the low-salinity high-turbidity zone, phosphate is-removed from solution during phytoplankton blooms, especially during spring. Blooms also affect the suspended matter composition, in that a shift towards biogenic elements (POC, N, P) at the expense of lithogenic elements (Fe, Al) occurs. Moreover, the speciation of particulate phosphorus shifts from iron- and aluminium-bound forms to POC-bound phosphate in zones of high primary productivity. These findings have implications for the future management of the Scheldt Estuary, as nutrient reduction policies are being implemented.
AN: 3696297
418 of 1521
TI: Potential rates of methanogenesis in sawgrass marshes with peat and marl soils in the Everglades
AU: Bachoon,-D.; Jones,-R.D.*
AF: Dep. Biol. Sci., Florida Int. Univ., Miami, FL 33199, USA
SO: SOIL-BIOL.-BIOCHEM. 1992 vol. 24, no. 1, pp. 21-27
LA: English
ER: F (Freshwater)
AB: Comparisons of methanogenesis in two sawgrass wetlands of the Florida Everglades revealed that marl soils had a much greater potential rate of methanogenesis than peat soils. In these wetlands methanogenesis decreased rapidly with increased soil depth, increased at higher temperatures, increased with lower Eh, was stimulated by organic compounds (cellulose, glucose and acetate), and remained unaffected by ammonium and phosphate. Lowering the Eh in peat and marl soils with sulfide or sulfate stimulated methanogenesis. Methanogenesis potentials decreased to undetectable values when water levels dropped below the surface, and peaked 1 month after heavy rainfall in November 1989.
AN: 3696288
419 of 1521
TI: Autotrophic picoplankton in southern Lake Baikal: Abundance, growth and grazing mortality during summer
AU: Nagata,-T.; Takai,-K.; Kawanobe,-K.; Kim,-D.; Nakazato,-R.; Guselnikova,-N.; Bondarenko,-N.; Mologawaya,-O.; Kostrnova,-T.; Drucker,-V.; Satoh,-Y.; Watanabe,-Y.
AF: Inst. Hydrosp.-Atmos. Sci., Nagoya Univ., Chikusa, Nagoya 464-01, Japan
SO: J.-PLANKTON-RES. 1994 vol. 16, no. 8, pp. 945-959
LA: English
ER: F (Freshwater)
AB: Autotrophic picoplankton were highly abundant during the thermal stratification period in late July in the pelagic area (water depth 500-1300 m) of southern Lake Baikal; maximum numbers were 2 x 10 super(6) cells/ml in the euphotic zone ( similar to 15 m). Unicellular cyanobacteria generally dominated the picoplankton community, although unidentified picoplankton that fluoresced red under blue excitation were also abundant (maximum numbers 4 x 10 super(5) cells/ml) and contributed up to similar to 40% of the total autotrophic picoplankton on occasions. Carbon and nitrogen biomasses of autotrophic picoplankton estimated by conversion from biovolumes were 14-84 mu g C/L and 3.6-21 mu g N/L. These were comparable to or exceeded the biomass of heterotrophic bacteria. Autotrophic picoplankton and bacteria accounted for as much as 33% of particulate organic carbon and 81% of nitrogen in the euphotic zone. Measurements of the photosynthetic uptake of [ super(14)C]bicarbonate and the growth of picoplankton in diluted or size-fractionated waters revealed that 80% of total primary production was due to picoplankton, and that much of this production was consumed by grazers in the < 20 mu m cell-size category. These results suggest that picoplankton-protozoan trophic coupling is important in the pelagic food web and biogeochemical cycling of Lake Baikal during summer.
AN: 3696278
420 of 1521
TI: Linkages between organic matter mineralization and denitrification in eight riparian wetlands
AU: Seitzinger,-S.P.
AF: Rutgers Univ., Inst. Mar. and Coast. Sci., P.O. Box 231, New Brunswick, NJ 08903-0231, USA
SO: BIOGEOCHEMISTRY 1994 vol. 25, no. 1, pp. 19-39
LA: English
ER: F (Freshwater)
AB: Denitrification (N sub(2) production) and oxygen consumption rates were measured at ambient field nitrate concentrations during summer in sediments from eight wetlands (mixed hardwood swamps, cedar swamps, health dominated shrub wetland, herbaceous peatland, and a wetland lacking live vegetation) and two streams. The study sites included wetlands in undisturbed watersheds and in watersheds with considerable agricultural and/or sewage treatment effluent input. Denitrification rates measured in intact cores of water-saturated sediment ranged from less than or equal to 20 to 260 mu mol N m super(-2)/h among the three undisturbed wetlands and were less variable (180 to 260 mu mol N m super(-2)/h) among the four disturbed wetlands. Denitrification rates increased when nitrate concentrations in the overlying water were increased experimentally (1 up to 770 mu M), indicating that nitrate was an important factor controlling denitrification rates. However, rates of nitrate uptake from the overlying water were not a good predictor of denitrification rates because nitrification in the sediments also supplied nitrate for denitrification. Regardless of the dominant vegetation, pH, or degree of disturbance, denitrification rates were best correlated with sediment oxygen consumption rates (r super(2) = 0.912) indicating a relationship between denitrification and organic matter mineralization and/or sediment nitrification rates. Rates of denitrification in the wetland sediments were similar to those in adjacent stream sediments. Rates of denitrification in these wetlands were within the range of rates previously reported for water-saturated wetland sediments and flooded soils using whole core super(15)N techniques that quantify coupled nitrification/denitrification, and were higher than rates reported from aerobic (non-saturated) wetland sediments using acetylene block methods.
AN: 3693285
421 of 1521
TI: The effect of pressure on leucine and thymidine incorporation by free-living bacteria and by bacteria attached to sinking oceanic particles
AU: Turley,-C.M.
AF: Plymouth Mar. Lab., Citadel Hill, Plymouth PL1 2PB, UK
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 11-12, pp. 2193-2206
LA: English
ER: M (Marine)
AB: The effect of pressure on upper ocean free-living bacteria and bacteria attached to rapidly sinking particles was investigated through studying their ability to synthesize DNA and protein by measuring their rate of super(3)H-thymidine and super(3)H-leucine incorporation. Studies were carried out on samples from the NE Atlantic under the range of pressures (1-430 atm) encountered by sinking aggregates during their journey to the deep-sea bed. Thymidine and leucine incorporation rates per bacterium attached to sinking particles from 200 m were about six and ten times higher, respectively, than the free-living bacterial assemblage. The ratio of leucine incorporation rate per cell to thymidine incorporation rate per cell was significantly different between the larger attached (18.9:1) and smaller free-living (10.4:1) assemblages. The rates of leucine and thymidine incorporation decreased exponentially with increasing pressure for the free-living and linearly for attached bacteria, while there was no significant influence of pressure on cell numbers. At 100 atm leucine and thymidine incorporation rate per free-living bacterium was reduced to 73 and 20%, respectively, relative to that measured at 1 atm. Pressure of 100 atm reduced leucine and thymidine incorporation per attached bacterium to 94 and 70%, and at 200 atm these rates were reduced to 34 and 51%, respectively, relative to those measured at 1 atm. There was no significant uncoupling of thymidine and leucine incorporation for either the free-living or attached bacterial assemblages with increasing pressure, indicating that the processes of DNA and protein synthesis may be equally affected by increasing pressure. It is therefore unlikely that bacteria, originating from surface waters, attached to rapidly sinking particles play a role in particle remineralization below approximately 1000-2000 m. These results may help to explain the occurrence of relatively fresh aggregates on the deep-sea bed that still contain sufficient organic carbon to fuel the rapid growth of benthic micro-organisms; they also indicate that the effect of pressure on microbial processes may be important in oceanic biogeochemical cycles.
AN: 3693223
422 of 1521
TI: Phaeopigment distribution during the 1990 spring bloom in the northeastern Atlantic
AU: Barlow,-R.G.; Mantoura,-R.F.C.; Gough,-M.A.; Fileman,-T.W.
AF: Plymouth Mar. Lab., Prospect Place, West Hoe, Plymouth PL1 3DH, UK
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 11-12, pp. 2229-2242
LA: English
ER: M (Marine)
AB: The temporal and depth distributions of phaeopigments were determined during a spring bloom in the northeastern Atlantic in 1990 using reverse phase high performance liquid chromatography. Phaeopigment concentrations were very low (<8% by mole relative to chlorophyll a) and two forms of phaeophorbide and two forms of phaeophytin were separated and quantified. Phaeophorbides were the dominant phaeopigments, accounting for 80% of the total phaeopigment molar concentration, and phaeopigments closely tracked the variations in chlorophyll a by increasing during the development phase of the bloom and declining in the post bloom stage. Production of phaeopigments was found to occur predominantly at night, and these rates exceeded the rates of phaeopigment destruction during the day. Lower phaeopigment-chlorophyll a ratios were determined for the surface waters, suggesting that photodegradation was possibly the primary mechanism of phaeopigment disappearance in the euphotic zone. A comparison of phaeopigment data and phyto- and zooplankton structure indicates that greater phaeopigment production and grazing pressure occurred in the development phase when diatoms dominated, while grazing and phaeopigment production declined in the post bloom stage dominated by prymnesiophytes.
AN: 3693194
423 of 1521
TI: Direct observations of advective nutrient and oxygen fluxes at 24 degree N in the Pacific Ocean
AU: Robbins,-P.E.; Bryden,-H.L.
AF: MIT/WHOI Joint Program Oceanogr., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1994 vol. 41, no. 1, pp. 143-168
LA: English
ER: M (Marine)
AB: Meridional oxygen and nutrient flux in the Pacific Ocean are estimated using a hydrographic transect at 24 degree N. A velocity field is diagnosed from the observed density structure using a least-squares inversion which insures mean net upwelling across isopycnal surfaces in the Pacific basin north of the transect. Uncertainties in the velocity field prevent the determination of a non-zero flux of nitrate and dissolved silica at 24 degree N. Net oxygen flux is southward owing to atmospheric exchange in conjunction with the temperature dependent gas solubility. Although net flux is poorly determined, the structure of the nutrient flux at 24 degree N is robust to uncertainties in the circulation: the surface wind driven circulation imports nutrients to the north Pacific while the deep overturning thermohaline circulation exports nutrients in the deep waters. Estimates of basin-scale nutrient remineralization and oxygen utilization rates are in agreement with published values derived from other methods. Mechanisms which contribute to the large scale nutrient budgets are quantitatively examined and horizontal advection is found to play a significant role.
AN: 3693193
424 of 1521
TI: Comparison of anaerobic and aerobic biodegradation of mineralized skeletal structures in marine and estuarine conditions
AU: Simon,-A.; Poulicek,-M.; Velimirov,-B.; Mackenzie,-F.T.
AF: Lab. Morphol., Syst. et Ecol. Anim., Univ. Liege. Inst. Zool., Quai Van Beneden 22, B-4020 Liege, Belgium
SO: BIOGEOCHEMISTRY 1994 vol. 25, no. 3, pp. 167-195
LA: English
ER: M (Marine); B (Brackish)
AB: The knowledge of the biodegradation rates is essential to studies of the biogeochemistry and ecology of aquatic systems. It helps us to quantify the production and uptake rates of chemical components and their recycling, and to understand the mechanisms and rates of organic matter accumulation in sediments. Experimental studies of biodegradation processes in six types of mineralized skeletons were performed in shallow-marine waters of Calvi Bay, Corsica and in estuarine waters of Roscoff, Brittany. Three types of mollusk shells, sea urchin skeletal plates, crab cuticle and fish vertebrae were exposed to oxic and anoxic conditions over periods of 15 days to 30 months. After recovery of the substrates, protein assays, bacterial counts and organic carbon analyses were performed. Quantitative protein assays and bacterial counts indicate that biodegradation of mineralized skeletal structures occurs at a slower rate in anoxic conditions than in oxic conditions. Bacterial analysis showed that in anoxic environment, less than 0.5% of the consumed organic matter is converted into bacterial biomass. The aerobic biodegradation rate was positively correlated with the organic content of the skeletons. Anoxic biodegradation of skeletons occurred at much slower rates in estuarine sediments than in shallow marine sediments. Preservation of skeletal structures in estuarine conditions appears to be correlated with the abundance of dissolved organic matter rather than with high sedimentation rates.
AN: 3693038
425 of 1521
TI: Allochthonous input of organic matter from different riparian habitats of an agriculturally impacted stream
AU: Delong,-M.D.; Brusven,-M.A.
AF: Biol. Dep., Winona State Univ., Winona, MN 55987, USA
SO: ENVIRON.-MANAGE. 1994 vol. 18, no. 1, pp. 59-71
LA: English
ER: F (Freshwater)
AB: Lapwai Creek, an agriculturally impacted stream in northern Idaho, was examined to determine longitudinal patterns of particulate allochthonous input from different riparian vegetation types. The stream, characterized by extensive removal of mature vegetation, was classified as having four riparian vegetation types: herbaceous, herbaceous-shrub mix, shrubs, and deciduous trees. Litterfall from each vegetation type was measured monthly for two years at eight locations along Lapwai Creek using 0.1-m super(2) baskets. Litterfall was lowest for herbaceous habitats and highest for deciduous tree habitats. Annual litterfall was low in the headwaters, which flow through an open meadow and deep canyon, and increased from the canyon-floodplain transition downstream to the first fifth-order site. Annual litterfall decreased markedly at the last two fifth-order stream sections. Differences in annual input rates between section 6 and sections 7 and 8, all of which are fifth order, can be attributed to removal of climax riparian vegetation. Estimates of actual and potential annual allochthonous income for each site suggest that current detrital inputs to Lapwai Creek are less than could be achieved if greater quantities of climax vegetation were still present. Lower rates of allochthonous inputs to Lapwai Creek may result in a system with detrital dynamics and macroinvertebrate communities different from that of comparable undisturbed streams of this region.
AN: 3692757
426 of 1521
TI: Total organic carbon in streamwater from four long-term monitored catchments in Norway
AU: Lydersen,-E.; Henriksen,-A.
AF: Norw. Inst. Water Res., 0411 Oslo, Norway
SO: ENVIRON.-INT. 1994 vol. 20, no. 6, pp. 713-729
LA: English
ER: F (Freshwater)
AB: By linear regression analyses, flux, concentration, and net charge (NC in mu eq/mg C) of total organic carbon (TOC) have been related to different physico-chemical parameters present in air/precipitation and streamwater at four long-term monitored catchments in Norway, during the period 1986-1992. The catchments vary a lot with respect to annual water input, acid rain, and the streamwater concentration of TOC. Thus, relationships between concentration/NC of TOC and chemical compounds in precipitation and streamwater were often catchment-specific. However, seasonal climatic changes, like air temperature and hydrology, were found to be important for the concentration variations of TOC. The correlation between concentration of nonmarine base cations ( capital sigma BC*) and concentration of TOC at the four sites was far more significant (r=0.86) than the corresponding correlation between nonmarine sulphate (SO sub(4)*) and capital sigma BC* (r=0.57). This indicates the important role of organic matter in weathering reactions in the catchment. Concerning weathering and cation leaching of aluminum, the correlation between concentration of total aluminum (RAL) and SO sub(4)* was far more significant (r=0.93) compared with the corresponding correlation between RAL and TOC (r=0.40). This should be expected, because a high concentration of SO sub(4)* means a low pH, which is needed to dissolve substantial amounts of Al from soils. The NC of TOC was found to be most affected by compounds in precipitation, primarily the inputs of sea salts. In the most acidified areas, the influence from strong acid inputs also affects the NC of TOC, but less significantly. The concentration of Na super(+) in precipitation is much higher and the variations much larger compared with the concentration of H super(+) in precipitation in the coastal areas, like Birkenes and especially Kaarvatn. Thus, it is reasonable that the variations in sea salt inputs (primarily NaCl) are more important for the temporary variation in NC of TOC compared with H super(+) ions at these sites. Only at Langtjern, the most TOC-influenced site, a significant and positive correlation was found between H super(+) and the concentration of TOC in streamwater. This indicates that at a certain TOC level, the weak organic acids may affect the streamwater pH. A comparison between measured and calculated concentrations of organic Al indicated that the dissociation constants (pK-values) of the organic acids present at Birkeness must be higher and/or the Al-complexing constants lower compared with the constants given by the programme. At the three other sites, it was the other way around. This may explain why a negative correlation between concentrations of TOC and labile Al was present at Birkenes, while the other sites exhibited a corresponding positive correlation with respect to labile Al or capital sigma Al super(n+). The comparison also documented larger differences in these constants between the sites, compared with monthly variations in the constants at one single site.
AN: 3692755
427 of 1521
TI: Production of isoprene by marine phytoplankton cultures
AU: Moore,-R.M.; Oram,-D.E.; Penkett,-S.A.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, NS B3H 4J1, Canada
SO: GEOPHYS.-RES.-LETT. 1994 vol. 21, no. 23, pp. 2507-2510
LA: English
ER: M (Marine)
AN: 3691433
428 of 1521
TI: Climatic warming and the decline of zooplankton in the California Current
AU: Roemmich,-D.; McGowan,-J.
AF: Mar. Life Res. Group, Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093-0230, USA
SO: SCIENCE-WASH. 1995 vol. 267, no. 5202, pp. 1324-1326
LA: English
ER: M (Marine)
AB: Since 1951, the biomass of macrozooplankton in waters off southern California has decreased by 80 percent. During the same period, the surface layer warmed-by more than 1.5 degree C in some places--and the temperature difference across the thermocline increased. Increased stratification resulted in less lifting of the thermocline by wind-driven upwelling. A shallower source of upwelled waters provided less inorganic nutrient for new biological production and hence supported a smaller zooplankton population. Continued warming could lead to further decline of zooplankton.
AN: 3691033
429 of 1521
TI: Spring-neap tidal contrasts and nutrient dynamics in a marsh-dominated estuary
AU: Voeroesmarty,-C.J.; Loder,-T.C.,III
AF: Inst. Study Earth, Oceans, Space, Morse Hall, Univ. New Hampshire, Durham, NH 03824, USA
SO: ESTUARIES 1994 vol. 17, no. 3, pp. 537-551
LA: English
ER: B (Brackish)
AB: This contribution presents a new perspective on water chemistry and its relation to tidal hydrology in marsh-dominated estuaries. Results are derived from both field and modeling experiments. A heuristic model based on a tidally-averaged advection-dispersion equation is used in conjunction with source-sink terms (for benthic, marsh surface, and open-water exchanges) to make predictions of nutrient concentrations in the water column. Spring-neap tidal contrasts are associated with significant changes in water-column chemistry for a variety of nutrients sampled during the growing season in the Parker River estuary (Massachusetts). For ammonium, phosphate, nitrate plus nitrite, total dissolved N, and total dissolved P, concentrations are significantly lower during spring tides (marshes flooded) than during neap tides (marshes unflooded). Model results indicate that physical changes and open-water processing are insufficient to produce the observed effect, and that explicit biogeochemical processing on marsh surfaces is required. Field observations of changes in nutrient to nutrient ratios with the onset of marsh inundation also support this conclusion. As tides progress from the neap to spring condition, a "spectrum" of trajectories emerges in salinity-nutrient plots developed from both observational datasets and model output. Care must therefore be exercised in designing sampling programs for water chemistry in marsh-dominated ecosystems and in interpreting the resulting mixing diagrams.
AN: 3690700
430 of 1521
TI: Internal nutrient budget in a shallow hypereutrophic lake
AU: Reddy,-K.R.; Gale,-P.M.
AF: Soil Water Sci. Dep., Univ. Florida, Gainesville, FL 32611, USA
CO: 14. Annu. International Symposium of the North American Lake Management Society, Orlando, FL (USA), 31 Oct-5 Nov 1994
SO: LAKE-RESERV.-MANAGE. 1994 vol. 9, no. 2, pp. 107-108
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Nutrient processing by aquatic biota and bottom sediments can be a major factor in determining the trophic status of a lake. The role of bottom sediments in nutrient release or retention becomes increasingly important in regulating water quality. The objective of this study was to determine the role of bottom sediments in overall nutrient budget of Lake Apopka, a shallow hypereutrophic lake located in Central Florida. As the head waters of the Oklawaha River system, Lake Apopka's water quality can significantly effect that of the lakes downstream. Since the lake has a large surface area and is quite shallow (mean depth of 2 m), stratification of the water column does not occur, as wind driven events can completely mix the system. Although point sources of nutrients such as raw citrus wastes and sewage have been eliminated, the drainage water pumpage from adjacent agricultural fields and the bottom sediments themselves continue to contribute to the nutrient load of the lake. Using the data obtained in the laboratory and field experiments on C, N and P cycle processes in sediment-water column of Lake Apopka, simple nutrient budgets were developed. These budgets suggest that external nutrient inputs to the lake are not always high enough to support the high level of primary productivity currently being measured in the lake. Thus, internal cycling of nutrients between the sediment and the overlying water column apparently contributes to the nutrient requirements of the algae. The lake is functioning as a net sink for C, N and P by transforming inorganic pools of nutrients into organic forms and depositing them on the sediment surface. In short-term, reduction in external loading may not result in significant changes in eutrophic status of the lake. The nutrient release due to diffusive and resuspension flux from bottom sediments can potentially supply most of the nutrient requirements of the algae. However, if the external nutrient loadings are curtailed, over a several year period of time nutrient limitation may occur in the lake as a result of reduction in nutrient supply from bottom sediments. The time period required to achieve nutrient limitation in the lake depends on the effectiveness of the restoration techniques implemented both within the lake and in the drainage basin.
AN: 3690172
431 of 1521
TI: Factors affecting nitrogen loss in experimental wetlands with different hydrologic loads
AU: Phipps,-R.G.; Crumpton,-W.G.
AF: Dep. Bot., Iowa State Univ., Ames, IA 50011, USA
SO: ECOL.-ENG. 1994 vol. 3, no. 4, pp. 399-408
NT: Special issue: Creating freshwater marshes in a riparian landscape.
LA: English
ER: F (Freshwater)
AB: Constructed or restored wetlands have great potential for reducing nonpoint source contamination of surface and ground waters by agricultural chemical contaminants. The work reported here combines field and experimental studies of factors affecting nitrogen loss in the Des Plaines River Experimental Wetlands, northeastern Illinois, USA. These wetlands receive approximately 5-36 cm/week of pumped river water with significant but seasonally variable loads of nitrate and organic nitrogen. On an annual basis, the wetlands removed 78-95% of the nitrate and 54-75% of the total nitrogen received. At the low hydrologic loading rate, organic nitrogen exports approximately equalled imports. However at the higher hydrologic loading rate, the wetlands exported 22-31% more organic nitrogen than received. Seasonal variation in nitrate and organic nitrogen loads had significant effects on the effectiveness of the wetlands as sinks for total nitrogen. The wetlands were nitrogen sinks during periods of high nitrate loading and nitrogen sources during periods of low nitrate loading. Experimental studies demonstrated the effects of nitrate concentration, temperature, and location on rates of nitrate loss. Results suggest that nitrate loading rates might influence not only nitrate loss rates but also loss rate coefficients.
AN: 3689468
432 of 1521
TI: Respiration and dissolution in the sediments of the western North Atlantic: Estimates from models of in situ microelectrode measurements of porewater oxygen and pH
AU: Hales,-B.; Emerson,-S.; Archer,-D.
AF: Univ. Washington Sch. Oceanogr., WB-10, Seattle, WA 98195, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1994 vol. 41, no. 4, pp. 695-719
LA: English
ER: M (Marine)
AB: We present in situ microelectrode measurements of sediment formation factor and porewater oxygen and pH from six stations in the North Atlantic varying in depth from 2159 to 5380 m. A numerical model of the oxygen data indicates that fluxes of oxygen to the sediments are as much as an order of magnitude higher than benthic chamber flux measurements previously reported in the same area. Model results require dissolution driven by metabolic CO sub(2) production within the sediments to explain the pH data; even at the station with the most undersaturated bottom waters >60% of the calcite dissolution occurs in response to metabolic CO sub(2). Aragonite dissolution alone cannot provide the observed buffering of porewater pH, even at the shallowest station. A sensitivity test of the model that accounts for uncertainties in the bottom water saturation state and the stoichiometry between oxygen consumption and CO sub(2) production during respiration constrains the dissolution rate constant for calcite to between 3 and 30%/day, in agreement with earlier in situ determinations of the rate constant. Model results predict that over 35% of the calcium carbonate rain to these sediments dissolves at all stations, confirmed by sediment trap and CaCO sub(3) accumulation data.
AN: 3689424
433 of 1521
TI: Causes and consequences of variability in the timing of spring phytoplankton blooms
AU: Townsend,-D.W.; Cammen,-L.M.; Holligan,-P.M.; Campbell,-D.E.; Pettigrew,-N.R.
AF: Dep. Oceanogr., Univ. Maine, Orono, ME 04469, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1994 vol. 41, no. 5-6, pp. 747-765
LA: English
ER: M (Marine)
AB: Established conceptual models of the initiation and progression of spring phytoplankton blooms are reconsidered in light of recent observations. We use biological simulation modelling as a tool for the analysis of spring plankton blooms in shallow, coastal waters in temperate latitudes of the North Atlantic. The model shows that interannual variability in the timing of bloom initiation arises from year-to-year differences in incident irradiation, as determined by weather (cloudiness). This variability in timing results in some years when the spring bloom occurs in cold water temperatures near 0 degree C. Model results suggest that due to low temperature inhibition of heterotrophic consumption, more fresh organic material is delivered to the benthos in these cold-water blooms than when the bloom occurs in waters only 3 degree C warmer. Thus we suggest that variable bloom timing can be important to the trophodynamic fate of bloom products. We suggest that variability in timing of spring phytoplankton blooms in offshore and open ocean waters is also related to weather, through controls on the light field and wind mixing. Our analyses of wind-driven vertical mixing demonstrate such blooms can begin following the winter period of deep convection, and prior to the vernal development of stratification, provided that wind speed is below a certain, predictable threshold, which we estimate. In such cases, there may be several spring bloom pulses, each interrupted by self-shading light limitation or vertical mixing events. Eventually the seasonal thermocline develops and nutrient exhaustion curtails bloom production. This means that the spring phytoplankton bloom in offshore and open ocean areas may be significantly more productive, result in more export production, and be more important to the carbon cycle, than has been previously assumed. Furthermore, these features of temperate marine planktonic ecosystems are not only sensitive to annual variations in weather, but also any trends that might result from greenhouse warming or other factors that affect the climate system.
AN: 3689412
434 of 1521
TI: The impact of a coccolithophore bloom on oceanic carbon uptake in the Northeast Atlantic during summer 1991
AU: Robertson,-J.E.; Robinson,-C.; Turner,-D.R.; Holligan,-P.; Watson,-A.J.; Boyd,-P.; Fernandez,-E.; Finch,-M.
AF: Plymouth Mar. Lab., Prospect Pl., Plymouth PL1 3DH, UK
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP. 1994 vol. 41, no. 2, pp. 297-314
LA: English
ER: M (Marine)
AB: Measurements of the carbonate system in the surface waters of the northeast Atlantic during summer 1991, following the main growth phase of a bloom of the coccolithophore Emiliania huxleyi are presented. We examine the perturbation of the carbonate system and assess the effect of calcification on the air-sea gradient of dissolved carbon dioxide in the surface ocean. An estimate of 1:1 organic to inorganic carbon uptake is calculated using the measurements of the surface carbonate parameters which is consistent with other estimates for E. huxleyi populations using radio-tracer methods. Using the changing ratio of dissolved carbon dioxide to nitrate concentration we demonstrate a relative increase in dissolved carbon dioxide due to calcification with evidence of this increase supported by estimates of the buffer factor and C:N assimilation ratios. Within the E. huxleyi bloom the effect of calcification on alkalinity appears to have reduced the air-sea gradient by similar to 15 mu atms (corrected to a constant temperature) using measurements from a 440 km section along the 20 degree W meridian. This reduction could prove to be significant in terms of the overall drawdown of carbon during the spring-summer season in this area.
AN: 3687928
435 of 1521
TI: Global oceanic and atmospheric oxygen stability considered in elation to the carbon cycle and to different time scales
AU: Duursma,-R.K.; Boisson,-M.P.R.M.
AF: Residence Les Marguerites, Appt. 15, 1305, Chemin des Rivoires, 06320 La Turbie, France
SO: OCEANOL.-ACTA 1994 vol. 17, no. 2, pp. 117-141
LA: English
ER: M (Marine)
AB: This paper constitutes an overview and synthesis concerning atmospheric and oceanic oxygen and related carbon dioxide, particular attention being paid to potential regulation mechanisms on different time scales. The world atmospheric oxygen reserve is remarkably large, so that a lack of oxygen will not easily occur, whether in confined spaces or in major conurbations. Atmospheric oxygen production began some 3.2 billion years ago, and has resulted in a net total amount of 5.63 x 10 super(20) mol (1.8 x 10 super(22) g) of oxygen, of which 3.75 x 10 super(19) mol is present as free oxygen in the atmosphere and 3.1 x 10 super(17) mol as dissolved oxygen in the oceans, the remainder being stored in a large number of oxidized terrestrial and oceanic compounds. The present global atmospheric oxygen level remains remarkably constant at a level of 20.946 plus or minus 0.006 vol %, with a slight decrease of 0.0004 O sub(2) vol %/yr (4 ppmv/yr) which is counter-correlated to CO sub(2) produced by fossil-fuel and biomass burning. The atmosphere-ocean exchange budget of CO sub(2) is dominated by the fossil-fuel and biomass fire-derived CO sub(2), of which 39 % is due to CO sub(2) increase in the atmosphere, 30 % is taken up by the oceans, the remainder possibly being recovered by biomass growth. Compared to the atmosphere-ocean flux of CO sub(2), the biogenic ocean fluxes of carbon ("oceanic biological pumps") are lower by a factor of at least ten (burial of organic matter and foraminifers, and reef growth).
AN: 3686514
436 of 1521
TI: Designing a simple microbiological-physical model for a coastal embayment
AU: Tett,-P.; Grenz,-C.
AF: Univ. Wales, Bangor: Sch. Ocean Sci., Menai Bridge, Gwynedd LL59 5EY, UK
SO: VIE-MILIEU 1994 vol. 44, no. 1, pp. 39-58
LA: English
ER: M (Marine)
AB: Numerical modelling provides a means of studying the processes that cycle nutrients and organic material as they pass through the coastal zone on their way from the land to the sea. The Gulf of Fos is an embayment on the Mediterranean coast of France, receiving part of the discharge of the Rhone river. We discuss the design of a simple numerical model for the Gulf. The model couples the physical processes of estuarine circulation, density stratification, and particulate resuspension, with the microbiological processes of light - and nutrient - controlled growth of pelagic micro-algae, bacteria and protozoans, and the detrital remineralisation of nutrients in water-column and sediment. Simple numerical experiments are used to show (1) the role of the Gulf in cycling land-derived nutrients before they reach the open sea; (2) the importance of particulate resuspension in controlling light availability for photosynthesis and the export of organic material; and (3) the high frequency of variability in this shallow, wind-forced system.
AN: 3686497
437 of 1521
TI: Influence of aquatic macrophytes on phosphorus and sediment porewater chemistry in a freshwater wetland
AU: Moore,-B.C.; Lafer,-J.E.; Funk,-W.H.
AF: Dep. Nat. Resour. Sci., Washington State Univ., Pullman, WA 99164-6410, USA
SO: AQUAT.-BOT. 1994 vol. 49, no. 2-3, pp. 137-148
LA: English
ER: F (Freshwater)
AB: The influence of the emergent aquatic macrophyte, Menyanthes trifoliata L. on sediment interstitial porewater chemistry, particularly on the distribution of soluble reactive phosphorus (SRP), was investigated at Silver Lake in southwestern Washington (Cowlitz County). Menyanthes trifoliata and many other wetland species create an oxygenated rhizosphere by translocation of oxygen to the roots. Close interval diffusion sampling showed that SRP, total soluble phosphorus (TSP), and concentrations of other redox-sensitive species such as T-Fe, Fe super(2+), and T-Mn were reduced in interstitial waters when macrophytes were present. Total alkalinity and pH also were lower and oxidation-reduction potentials were higher in sediments with plants than those in which the plants were removed. Rhizosphere oxidation appears to provide wetland species with a mechanism for sequestering phosphorus and for creating favorable concentration gradients within the root zone.
AN: 3684435
438 of 1521
TI: Sulfate reduction and sediment metabolism in Tomales Bay, California
AU: Chambers,-R.M.; Hollibaugh,-J.T.; Vink,-S.M.
AF: Tiburon Cent. Environ. Stud., San Francisco State Univ., P.O. Box 855, Tiburon, CA 94920, USA
SO: BIOGEOCHEMISTRY 1994 vol. 25, no. 1, pp. 1-18
LA: English
ER: B (Brackish)
AB: Sulfate reduction rates (SRR) in subtidal sediments of Tomales Bay, California, were variable by sediment type, season and depth. Higher rates were measured in near-surface muds during summer (up to 45 nmol cm super(-3)/h), with lower rates in sandy sediments, in winter and deeper in the sediment. Calculations of annual, average SRR throughout the upper 20 cm of muddy subtidal sediments (about 30 mmol S m super(-2)/d) were much larger than previously reported net estimates of SRR derived from both benthic alkalinity flux measurements and bay wide, budget stoichiometry (3.5 and 2.6 mmol m super(-2)/d, respectively), indicating that most reduced sulfur in these upper, well-mixed sediments is re-oxidized. A portion of the net alkalinity flux across the sediment surface may be derived from sulfate reduction in deeper sediments, estimated from sulfate depletion profiles at 1.5 mmol m super(-2)/d. A small net flux of CO sub(2) measured in benthic chambers despite a large SRR suggests that sediment sinks for CO sub(2) must also exist (e.g., benthic microalgae).
AN: 3680775
439 of 1521
TI: Recent advances in freshwater ecology
AU: Jones,-J.G.
AF: Freshwat. Biol. Assoc., Ferry House, Far Sawrey, Ambleside Cumbria LA22 0LP, UK
CO: 2. Reunion Argentina de Limnologia, La Plata (Argentina), Nov 1991
SO: CONFERENCES-ON-LIMNOLOGY.#CONFERENCIAS-DE-LIMNOLOGIA. Boltovsky,-A.;Lopez,-H.L.-eds. 1993 pp. 159-169
LA: Spanish
ER: F (Freshwater)
AB: The paper examines aspects of current research in freshwater ecology at three levels. The application of techniques of molecular biology has permitted significant advances, not least in the area of bacterial population ecology. At the other end of the scale these methods will permit us to determine the degree of relatedness of different fish stocks. The analysis of phytoplankton populations has now reached the stage where the results of several long term programmes can be combined to produce truly predictive models. Finally the knowledge that has been gained during the study of biogeochemical cycles can now be applied in the active management of lakes and reservoirs. This has been particularly successful when management strategies have been employed to counter the acidity of both natural and man-made water bodies.
AN: 3680215
440 of 1521
TI: Carbonate systems in the Baltic and Weddell Seas: Inventories and influences by man
AU: Ohlson,-M.
CA: Goeteborg Univ./Chalmers Univ. of Technology (Sweden). Dep. of Analytical and Marine Chemistry
SO: 1991 32 pp
NT: NTIS Order No.: DE92506616/GAR. Thesis (FD). 28 refs.
RN: NEI-SE-94 (NEISE94)
LA: English
ER: M (Marine)
AB: The result of recent measurements of the total alkalinity and calcium in the Baltic Sea are presented. The 1986 investigation gives a significantly different calcium to total alkalinity ratio (0.691) compared to literature values (0.41). Explanations for the difference in calcium to total alkalinity ratio are offered, based on reactions in the drainage basins including decay of organic matter, precipitation of acid rain and dissolution of carbonate minerals. From later investigations a more reasonable explanation seems that the shift is due to chemical patchiness in the Baltic proper. In spite of the acidic precipitation and the increased partial pressure of carbon dioxide in the atmosphere it seems that the carbonate system has not changed dramatically during the century. Existing fluctuations are mainly depending on the season and the inflow of dense water from the Kattegat/North Sea. A carbonate model has been coupled to a one-dimensional physical and biogeochemical model of the Baltic proper. The considered regulating mechanisms have been the atmospheric carbon dioxide pressure, the river run-off concentration of total alkalinity and total carbonate, and the total alkalinity in the precipitation. With the present concentrations of the above regulating mechanisms the uptake of atmospheric carbon dioxide by the Baltic proper gets about 12 g C/m(sup 2)/year and the net sedimentation gets about 8 g C/m(sup 2)/year. Total carbonate data from the southern Weddell Sea, collected during the Swedish Antarctic Expedition in 1988-1989, have been investigated with respect to the contribution of anthropogenic carbon dioxide. The anthropogenic carbon dioxide mean concentration varies in the different water masses from about 36 (mu)mol/kg in the Ice Shelf water to 8 (mu)mol/kg in the Antarctic bottom water. The evaluated annual transport of anthropogenic carbon amounts to 8x10(sup 12) g for this special area. [U.S. Sales Only.] (DBO)
AN: 3679965
441 of 1521
TI: Interhemispheric transport of carbon through the ocean
AU: Broecker,-W.S.; Peng,-T.H.
CA: Oak Ridge Natl. Lab., TN (USA)
SO: 1991 22 pp
NT: NTIS Order No.: DE92007246/GAR.
RN: CONF-9109340-2 (CONF91093402)
LA: English
ER: M (Marine)
AB: A case is made that the Atlantic's conveyor circulation carries roughly 0.6 gigatons of carbon (as (Sigma)CO(sub 2)) from the northern to the southern hemisphere. The return transport of this carbon (as CO(sub 2)) through the atmosphere would maintain a 1.6 ppm south to north gradient in atmospheric CO(sub 2) content. Such a gradient would go a long way toward explaining the current lower than expected fossil fuel CO(sub 2) supported north to south atmospheric gradient and hence would alleviate the necessity for the large northern hemisphere terrestrial sink proposed by Tans et al., 1990. [Contract AC05-84OR21400. Ciocco global cycle meeting (2nd), Ciocco (Italy), 8-20 Sep 1991. Sponsored by Department of Energy, Washington, DC.] (DBO)
AN: 3679892
442 of 1521
TI: Simulations of the carbon cycle in the oceans. (Part 3): (Annual report)
AU: Siegenthaler,-U.
CA: Bern Univ. (Switzerland)
SO: 1991 18 pp
NT: NTIS Order No.: DE91017410/GAR.
RN: DOE/ER/61054-1 (DOEER610541)
LA: English
ER: M (Marine)
AB: Our original goal of modelling the impact of seasonality on CO(sub 2) uptake in the ocean should be completed during the next year, now that the study of the effect of iron fertilization on global CO(sub 2) levels has been completed. The analysis of existing 3D nitrogen circulation models is nearing completion, and will produce two manuscripts. A combined carbon/nitrogen mixed layer ecosystem model has been completed and the equations were made available for inclusion in the Princeton North Atlantic General Circulation Model. A coupled air/sea model of anthropogenic CO(sub 2) uptake is currently under development, and development of this model is our highest priority in the next year. (MHB). [Contract FG02-90ER61054. Sponsored by Department of Energy, Washington, DC.] (DBO)
AN: 3679803
443 of 1521
TI: Dynamics of phosphorus in lake systems
AU: Kenney,-B.C.
CA: Inland Waters Dir., Ottawa, ON (Canada)
SO: 1990 55 pp
NT: NTIS Order No.: MIC-91-02049/GAR.
LA: English
ER: F (Freshwater)
AB: The phosphorus loading concept is examined within the framework of equilibrium input-output models. Some theoretical and practical shortcomings of several phosphorus models are then discussed. Finally, the dynamics of total phosphorus in lakes is explored using first-order linear theory with time-dependent coefficients.
AN: 3677651
444 of 1521
TI: Climate-related variations in denitrification in the Arabian Sea from sediment super(15)N/ super(14)N ratios
AU: Altabet,-M.A.; Francois,-R.; Murray,-D.W.; Prell,-W.L.
AF: Mar. Chem. and Geochem. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: NATURE 1995 vol. 373, no. 6514, pp. 506-509
LA: English
ER: M (Marine)
AB: Denitrification--the process by which nitrate is reduced to gaseous nitrogen species (usually N sub(2) or N sub(2)O)--is the dominant mechanism for removal of fixed nitrogen from the biosphere. In the oceans, denitrification is mediated by bacteria in suboxic environments and, by controlling the supply of fixed nitrogen, is an important limiting factor for marine productivity. Denitrification produces substantial super(15)N enrichment in subsurface nitrate, which is reflected in the isotopic composition of sinking particulate nitrogen; sediment super(15)N/ super(14)N ratios in regions with suboxic water columns may therefore provide a record of past changes in denitrification intensity. Here we report nitrogen isotope data for sediment cores from three sites in the Arabian Sea. At all three sites we find large, near-synchronous downcore variations in super(15)N/ super(14)N, which are best explained by regional changes in the isotopic composition of subsurface nitrate, and hence denitrification. Moreover, these variations are synchronous with Milankovitch cycles, thereby establishing a link with climate. We argue that these large, climate-linked variations, in a region that contributes significantly to global marine denitrification, are likely to have perturbed marine biogeochemical cycles during the Late Quaternary period.
AN: 3676502
445 of 1521
TI: Beyond global warming: Ecology and global change
AU: Robert,-H.; MacArthur,-A.L.
AF: Dep. Biol. Sci., Stanford Univ., Stanford, CA 94305, USA
SO: ECOLOGY 1994 vol. 75, no. 7, pp. 1861-1876
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: While ecologists involved in management or policy often are advised to learn to deal with uncertainty, there are a number of components of global environmental change of which we are certain--certain that they are going on, and certain that they are human-caused. Some of these are largely ecological changes, and all have important ecological consequences. Three of the well-documented global changes are: increasing concentrations of carbon dioxide in the atmosphere; alterations in the biogeochemistry of the global nitrogen cycle; and ongoing land use/land cover change. These three and other equally certain components of global environmental change are the primary causes of anticipated changes in climate, and of ongoing losses of biological diversity. They are caused in turn by the extraordinary growth in size and resource use of the human population. On a broad scale, there is little uncertainty about any of these components of change or their causes. However, much of the public believes the causes--even the existence--of global change to be uncertain and contentious topics. By speaking out effectively, we can help to shift the focus of public discussion towards what can and should be done about global environmental change.
AN: 3676293
446 of 1521
TI: Simulation model of the coupling between nitrification and denitrification in a freshwater sediment
AU: Blackburn,-T.H.; Blackburn,-N.D.; Jensen,-K.; Risgaard-Petersen,-N.
AF: Dep. Microb. Ecol., Inst. Biol. Sci., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark
SO: APPL.-ENVIRON.-MICROBIOL. 1994 vol. 60, no. 9, pp. 3089-3095
LA: English
ER: F (Freshwater)
AB: A model was constructed to simulate the results of experiments which investigated nitrification and denitrification in the freshwater sediment of Lake Vilhelmsborg, Denmark. The model output faithfully represented the profiles of O sub(2) and NO sub(3) super(-) and rates of nitrification, denitrification, and O sub(2) consumption as the O sub(2) concentration in the overlying water was increased from 10 to 600 mu M. The model also accurately predicted the response, to increasing O sub(2) concentrations, of the integrated (micromoles per square meter per hour) rates of nitrification and denitrification. The simulated rates of denitrification of NO sub(3) super(-) diffusing from the overlying water (D sub(w)) and of NO sub(3) super(-) generated by nitrification within the sediment (D sub(n)) corresponded to the experimental rates as the O sub(2) concentration in the overlying water was altered. The predicted D sub(w) and D sub(n) rates, as NO sub(3) super(-) concentration in the overlying water was changed, closely resembled those determined experimentally. The model was composed of 41 layers 0.1 mm thick, of which 3 represented the diffusive boundary layer in the water. Large first-order rate constants for nitrification and denitrification were required to completely oxidize all NH sub(4) super(+) diffusing from the lower sediment layers and to remove much of the NO sub(3) super(-) produced. In addition to the flux of NH sub(4) super(+) from below, the model required a flux of an electron donor, possibly methane. Close coupling between nitrification and denitrification, achieved by allowing denitrification to tolerate some O sub(2) ( similar to 10 mu M), was necessary to reproduce the real data. Spatial separation of the two processes (no toleration by denitrification of O sub(2)) resulted in too high NO sub(3) super(-) concentrations and too low rates of denitrification.
AN: 3673347
447 of 1521
TI: Changes in oceanic and terrestrial carbon uptake since 1982
AU: Francey,-R.J.; Tans,-P.P.; Allison,-C.E.; Enting,-I.G.; White,-J.W.C.; Trolier,-M.
AF: CSIRO Div. Atmos. Res., Priv. Bag 1, Mordialloc, Vic. 3195, Australia
SO: NATURE 1995 vol. 373, no. 6512, pp. 326-330
LA: English
AB: Changes in the carbon isotope ratio ( delta super(13)C) of atmospheric CO sub(2) can be used in global carbon-cycle models to elucidate the relative roles of oceanic and terrestrial uptake of fossil-fuel CO sub(2). Here we present measurements of delta super(13)C made at several stations in the Northern and Southern hemispheres over the past decade. Focusing on the highest-quality data from Cape Grim (41 degree S), which also provide the longest continuous record, we observed a gradual decrease in delta super(13)C from 1982 to 1993, but with a pronounced flattening from 1988 to 1990. There is an inverse relationship between CO sub(2) growth rate and El Nino/Southern Oscillation (ENSO) events which is not reflected in the isotope record. Thus, for the ENSO events in 1982, 1986 and 1991-92, we deduce that net ocean uptake of CO sub(2) increased, whereas during La Nina events, when equatorial sea surface temperatures are lower, upwelling of carbon-rich water increases the release of CO sub(2) from the oceans. The flattening of the trend from 1988 to 1990 appears to involve the terrestrial carbon cycle, but we cannot yet ascribe firm causes. We find that the large and continuing decrease in CO sub(2) growth starting in 1988 involves increases in both terrestrial and oceanic uptake, the latter persisting through 1992.
AN: 3671992
448 of 1521
TI: Ecosystem changes in the North Pacific Subtropical Gyre attributed to the 1991-92 El Nino
AU: Karl,-D.M.; Letelier,-R.; Hebel,-D.; Tupas,-L.; Dore,-J.; Christian,-J.; Winn,-C.
AF: SOEST, Dep. Oceanogr., Univ. Hawaii, Honolulu, HI 96822, USA
SO: NATURE 1995 vol. 373, no. 6511, pp. 230-234
LA: English
ER: M (Marine)
AB: Subtropical ocean gyres are considered to be the marine analogues of terrestrial deserts because of chronic nutrient depletion and low standing stocks of organisms. Despite their presumed low rates of primary and export production, oligotrophic habitats contribute significantly to global productivity because of their large extent. Therefore, even small changes in ecosystem production can produce large effects in the global carbon cycle. The North Pacific Subtropical Gyre has generally been thought to support a homogeneous, stable biological community, but recent investigations have suggested instead that the ecosystem of this gyre is temporally and spatially variable. The causes of this variability are not well understood. Here we present evidence of a major change in the structure and productivity of the pelagic ecosystem in the Subtropical North Pacific Ocean, an effect that we attribute to the 1991-92 El Nino-Southern Oscillation (ENSO) event. Decreased upper-ocean mixing and a change in circulation resulted in an increased abundance and activity of nitrogen-fixing micro-organisms and a shift from a primarily nitrogen-limited to a primarily phosphorus-limited habitat with attendant changes in total and export production and in nutrient cycling pathways and rates.
AN: 3671939
449 of 1521
TI: Iron limitation and the cyanobacterium Synechococcus in equatorial Pacific waters
AU: Wells,-M.L.; Price,-N.M.; Bruland,-K.W.
AF: Inst. Mar. Sci. Univ. California, Santa Cruz, CA 95064, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 6, pp. 1481-1486
LA: English
ER: M (Marine)
AB: Iron enrichments in bottle experiments in high nutrient, low chlorophyll (HNLC) surface waters typically stimulate the net growth of nanophytoplankton (2.0-20 mu m) but not picophytoplankton (<2.0 mu m), suggesting either that picophytoplankton are not Fe limited or that any increased picophytoplankton growth is balanced by increased microzooplankton grazing rates. Using a novel approach in which we diminish iron availability in seawater with the fungal siderophore deferriferrioxamine B, we demonstrate that growth of the abundant picoplanktonic cyanobacterium Synechococcus is not strongly rate limited by Fe in the HNLC equatorial Pacific Ocean. However, experiments at the equator and 5 degree S show an unsuspected non-uniformity in iron nutrition within this HNLC region. Furthermore, our results indicate that a major portion of "dissolved" (<0.4 mu m) iron in these waters is unavailable to Synechococcus, providing the first evidence that a significant fraction of dissolved iron occurs in forms other than the simple hydroxy species predicted by thermodynamic models. Deferriferrioxamine B affords a powerful new tool for probing the iron nutrition of marine phytoplankton and can provide unique insight into the role of iron in marine biogeochemical cycles.
AN: 3670139
450 of 1521
TI: Effects of sinking and zooplankton grazing on the release of elements from planktonic debris
AU: Lee,-B.-G.; Fisher,-N.S.*
AF: Mar. Sci. Res. Cent., State Univ. of New York, Stony Brook, NY 11794-5000, USA
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 110, no. 2-3, pp. 271-281
NT: Bibliogr.: 55 ref.
LA: English
ER: M (Marine)
AB: Laboratory radiotracer experiments compared the effects of zooplankton grazing and microbial decomposition on the release of organic C and Ag, Cd, Co, Pb and Po from phytoplankton cells. After 40 h incubation of diatoms with copepods + microorganisms, 70% of the diatom cellular C was remineralized to CO sub(2) (40%), assimilated in copepod tissue (20%), excreted in fecal pellets (5%) or released as DOC (5%); microorganisms alone removed half this amount of diatom C. Copepod grazing enhanced the conversion of Ag from diatom cells to other forms (particulate and dissolved) by 27%, Po by 25 %, Pb by 20% Cd by 13%, and Co by 10%, over those cells incubated with only microorganisms; zooplankton grazing increased by 5 to 15%, the release of elements from diatom cells into the dissolved phase. Decomposing copepod fecal pellets, held free-falling on a spinning wheel, lost about 20% more C, Ag, Co and Pb than did undisturbed fecal pellets, while no appreciable difference was observed for release of metals from copepod carcasses treated similarly. The results suggest that retention of an element contained primarily in the cytoplasm of phytoplankton cells (such as C or Cd) is largely governed by microbial activity and leaching. Microbial activity has a smaller effect on particle-reactive elements (Ag and Pb) bound to structural components of cells; zooplankton are effective in removing these unassimilable elements by grazing and packaging them into rapidly sinking fecal pellets.
AN: 3668626
451 of 1521
TI: Grazer-mediated regeneration and assimilation of Fe, Zn and Mn from planktonic prey
AU: Hutchins,-D.A.; Bruland,-K.W.
AF: Mar. Sci. Res. Cent., SUNY Stony Brook, NY 11794-5000, USA
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 110, no. 2-3, pp. 259-269
NT: Bibliogr.: 45 ref.
LA: English
ER: M (Marine)
AB: Experiments were performed to investigate grazer remineralization and assimilation of Fe, Zn and Mn from autotrophic and heterotrophic plankton prey. Metal isotope activity incorporated into planktonic prey was added to bottles containing crustacean zooplankton grazers, and distribution of the added metals into dissolved, fecal pellet and grazer fractions was monitored over time. At the end of a 9 to 10 h grazing period, concentrations of dissolved metal isotopes were approximately 3 to 7 times higher in bottles with grazers than in control bottles without grazers. An experiment in which flagellate grazers were fed Fe-labeled cyanobacteria suggested that protozoans may also remineralize trace metals ingested with prey. Metal assimilation efficiencies from diatom and flagellate prey were determined in crustacean grazers; efficiencies energy creased in the order Zn > Fe > Mn. These experiments indicate that biologically required trace metals behave much like major nutrients during grazing, and suggest that biologically mediated regeneration and recycling could be an important part of the marine biogeochemical cycles of Fe, Zn and Mn.
AN: 3668625
452 of 1521
TI: Coexistence of sulfate reduction and methane production in an organic-rich sediment
AU: Holmer,-M.; Kristensen,-E.
AF: Dep. Life Sci. and Chem., Roskilde Univ., P.O. Box 260, DK-4000 Roskilde, Denmark
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 107, no. 1-2, pp. 177-184
NT: Bibliogr.: 35 ref.
LA: English
ER: M (Marine)
AB: Anaerobic mineralization processes were studied over a period of 40 d in an organic-rich sediment amended with labile organic matter (fish food pellets). Although measured sulfate reduction rates (SRR) were high (up to similar to 2400 nmol/cm super(3)/d), a coexistence between sulfate-reducing bacteria (SRB) and methane-producing bacteria (MPB) was evident. Methane production rates (MPR) of the same order of magnitude as SRR (up to similar to 1300 nmol/cm super(3)/d) occurred even when sulfate was present in high concentrations (5 to 60 mM). Acetate was an important substrate for the SRB initially, but its role diminished after 180 h of incubation, indicating that SRB used other substrates than acetate. There was only minor competition for acetate between SRB and MPB, as indicated by the lack of effect on MPR by inhibition of SRB with molybdate. This provides a possible explanation for the coexistence between SRB and MPB; in this organic-rich sediment the concentration of competitive substrates either exceeds the competition level or substrates are used noncompetitively.
AN: 3668462
453 of 1521
TI: A comparative study on 5'- nucleotidase (5'-nase) and alkaline phosphatase (APA) activities in two lakes
AU: Siuda,-W.; Guede,-H.
AF: Dep. Microbiol. Ecol., Inst. Microbiol., Univ. Warsaw, Ul. Karowa 18, Warsaw, Poland
SO: ARCH.-HYDROBIOL. 1994 vol. 131, no. 2, pp. 211-229
NT: Bibliogr.: 52 ref.
LA: English
ER: F (Freshwater)
AB: Phosphorus regeneration by 5'-nucleotidase (5'-nase) and alkaline phosphatase (APA) was studied in the pelagic zones of two German lakes. The obtained results supported the existence of an enzymatic mechanism of phosphorus-regeneration in pelagic lake water, which appears to be distinct from APA and is presumed to be represented by 5'-nucleotidases of bacterial origin. These enzymes exhibit a high substrate-affinity and a high specificity for nucleotides. In contrast to APA, no inhibition of activity by inorganic phosphorus (Pi) was observed. However, the enzymes could be strongly inhibited by Ni super(2+) ions and to some extent by Glucose-6-Phosphate. As was exemplified with ATP as substrate, the Pi released by these enzymes was much in excess of the uptake capacities of the plankton community at high substrate concentrations. At these conditions the majority of the planktonic uptake of the released Pi occurred in the algal size fraction. However, the coupling between release and uptake became much stronger at lower substrate concentrations, coinciding with an increased percentage of bacterial uptake. The obtained results suggest that regeneration of orthophosphate by the 5'-nase system may be more significant for the phosphorus dynamics of the whole planktonic community as compared to Pi liberation by APA activities.
AN: 3668441
454 of 1521
TI: Seasonal variation in sediment urea turnover in a shallow estuary
AU: Therkildsen,-M.S.; Lomstein,-B.A.
AF: Dep. Microbial Ecol., Inst. Biol. Sci., Univ. Aarhus, DK-8000 Aarhus, Denmark
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 109, no. 1, pp. 77-82
NT: Bibliogr.: 33 ref.
LA: English
ER: M (Marine)
AB: A seasonal study of sediment urea turnover rates was carried out in a shallow Danish estuary. Turnover, rates decreased with sediment depth (0 to 16 cm) and were within the range 1.2 to 424.8 nmol N/cm super(3)/d. Integrated (0 to 16 cm depth) turnover rates varied between 1.5 and 16.9 mmol N/m super(2)/d with a maximum in July and a minimum in January. Urea turnover followed first-order rate kinetics, as the urea turnover rate constant, k sub(urea), was independent of the urea concentration, and the urea turnover rates were positively related to the latter. The urea turnover rate and rate constant were positively related to temperature. Urea production was stimulated by availability of high quality organic material (low C/N) and temperature. Urea production rates and urea concentrations in the sediment reached a maximum in July, when C-mineralization, temperature, and the quality of organic material were maximal, and there was a high benthic macrofaunal biomass. Secondary maxima in urea concentrations matched major phytoplankton sedimentation events in spring and autumn. Urea-N accounted for 7 to 55%, of the total N pool (urea + NH sub(4) super(+) + N0 sub(3) super(-) + NO sub(2) super(-)) in the sediment surface (0 to 1 cm.) The NH sub(4) super(+) pool was positively related to the urea turnover rate ( sigma 0 to 16 cm). Urea turnover accounted for a major part of the NH sub(4) super(+) production in the sediment.
AN: 3668397
455 of 1521
TI: Network analysis on nitrogen cycling in a coastal lagoon
AU: Fores,-E.; Christian,-R.R.; Comin,-F.A.; Menendez,-M.
AF: Dep. Ecol., Fac. Biol., Univ. Barcelona, Diagonal 645, E-08028 Barcelona, Spain
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 106, no. 3, pp. 283-290
NT: Bibliogr.: 33 ref.
LA: English
ER: M (Marine)
AB: Network analysis was applied to nitrogen cycling data from 6 ecosystem components (phytoplankton, Potamogeton pectinatus, Ruppia cirrhosa, detritus plus heterotrophs, sediment, and dissolved inorganic nitrogen) in Tancada Lagoon (Ebro River delta, NE Spain) to ascertain (1) the relative importance of internal recycling versus external exchanges, (2) the main biogeochemical processes and (3) the fate of nitrogen imported to the lagoon. We compared cycling from 2 periods of the year: May-October, dominated by freshwater inputs, and November-April, dominated by seawater. Nitrogen recycling in the lagoon is equal to or more important than exchanges with other ecosystems, as indicated by the Finn Cycling Index (FCI). FCI values are the percentage of total flow in the network which is associated with internal cycles and not with imports or exports. These internal cycles involve flows from a compartment that can be traced through 1 or more other compartments and back to the original. FCI values were 62% during the freshwater period and 52% during the seawater period. Nitrogen input to the lagoons was mainly as detritus plus heterotroph nitrogen (0.81 and 0.51 mmol N m super(-2) d super(-1) during the fresh- and seawater periods respectively). Most nitrogen export was as phytoplankton (0.2 mmol N m super(-2) d super(-1) during both periods). Denitrification rates were comparable to other exports (0.17 and 0.09 mmol m super(-2) d super(-1) during the fresh- and seawater periods respectively). Sediment played a key role in the international recycling of nitrogen. A total of 80% of the phytoplankton nitrogen flow came indirectly from ammonium fluxes between sediment and water during the freshwater period, and 60% during the seawater period. Thus several differences were noted in the N cycles between these 2 periods involving both the amount of recycling and the relative importance of different processes to the fate of nitrogen.
AN: 3668123
456 of 1521
TI: Simulated degradation of phytodetritus in deep-sea sediments of the NE Atlantic (47 degree N, 19 degree W)
AU: Poremba,-K.
AF: Inst. Meereskd., Univ. Kiel, Abt. Mar. Mikrobiol., Duesternbrooker Weg 20, D-24105 Kiel, FRG
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 105, no. 3, pp. 291-299
NT: Bibliogr.: 54 ref.
LA: English
ER: M (Marine)
AB: The degradation of phytodetritus in the deep sea was studied in sediment samples of the NE Atlantic in spring and summer 1992 using super(14)C-labelled algal cells (Anacystis) fed to the benthic population in ship-board experiments and measuring the liberation of labelled super(14)CO sub(2) over time. The mineralization process showed a 2-step behaviour with an initial rapid rate which later slowed down, indicating the initial attack of easily degradable material of the complex food and the later utilization of less labile matter. The profile of degradation activity with sediment depth showed no clear vertical gradient in March, but in August the activity in the top horizon increased by a factor of 6.1 to 7.8, which was coherent with increased bacterial numbers or biomass (factor of 1.3 to 1.7), respectively, and might be caused by the seasonal input of phytodetritus to the deep-sea bottom. The degradation measured was positively influenced by elevated incubation pressure mostly in summer, indicating that the summer stimulation of microbial activity in 1992 was based on the metabolic activation of the indigenous benthic community, while surface-derived organisms attached to sedimented particles were of lesser importance with respect to consumption of phytodetritus.
AN: 3668115
457 of 1521
TI: Past and present biomineralization processes. Considerations about the carbonate cycle. IUCN-COE Workshop, Monaco, 15-16 November 1993
AU: Doumenge,-F.; Allemand,-D.; Toulemont,-A.-(eds.)
AF: Musee Oceanogr. Monaco, Monaco
CO: Past and Present Biomineralization Processes. Considerations about the Carbonate Cycle. IUCN-COE Workshop, Monaco (Monaco), 15-16 Nov 1993
SO: BULL.-INST.-OCEANOGR.-MONACO MONACO-MONACO MUSEE-OCEANOGRAPHIQUE 1994 no. Spec. Iss. 13, 196 pp
LA: English
ER: M (Marine)
AB: Two days of open pluridisciplinary workshops were organized (on November 15 and 16) to appraise the information required and suggest new hypotheses and directions for research in all the areas relating to carbon and carbonate cycles. These six colloquia, each organized and directed by a guest speaker, highlighted various regulatory mechanisms for maintaining life on earth, despite the episodic distortions of the space-time continuum. Today, the time has come to proceed with a broad pluridisciplinary platform so as to reinterpret the major palaeontological crises in the light of current mechanisms. In this context, our guest speakers stimulated a general discussion on some key phenomena: The unity of these contributions lies in a common concern for: 1) introducing original ideas and approaches to open new directions for research; 2) identifying the state of current knowledge, along with often considerable gaps, thus revealing areas for research; 3) supplying accurate information on each topic from a pluridisciplinary viewpoint, with abundant bibliographic references and illustrations. The lively and always productive discussions following these presentations reflect the broad interest of the scientific community and provide ample food for thought. The outcome of these two days is particularly stimulating. It is a clear encouragement to pursue structured research projects through networks - formal and informal - ensuring collaboration between researchers and providing further support for scientific institutions. Our hope is not only that this work supplies an effective tool for information and reflection, but that it also acts as a catalyst for all the good intentions expressed during this exceptionally productive symposium.
AN: 3666664
458 of 1521
TI: Strategies for the study of climate forcing by calcification
AU: Westbroek,-P.; Buddemeier,-B.; Coleman,-M.; Kok,-D.J.; Fautin,-D.; Stal,-L.
AF: Dep. Chem., Leiden Univ., P.O. Box 9502, 2300 RA Leiden, Netherlands
CO: Past and Present Biomineralization Processes. Considerations about the Carbonate Cycle. IUCN-COE Workshop, Monaco (Monaco), 15-16 Nov 1993
SO: PAST-AND-PRESENT-BIOMINERALIZATION-PROCESSES.-CONSIDERATIONS-ABOUT-THE-CARBONATE-CYCLE.-IUCN-COE-WORKSHOP,-MONACO-MONACO,-15-16-NOVEMBER-1993. Doumenge,-F.;Allemand,-D.;Toulemont-A.-eds. MONACO-MONACO MUSEE-OCEANOGRAPHIQUE 1994 no. Spec. Iss. 13 pp. 37-60
ST: BULL.-INST.-OCEANOGR.-MONACO no. Spec. Iss. 13
LA: English
ER: M (Marine)
AB: The massive biological intervention in the climate system and the complexity of the biological response to global change call for a coordinated and well-organised scientific effort. In this paper we propose a hierarchical systems approach to study one particular aspect of geosphere-biosphere interactions - the marine cycle of calcium carbonate. The bulk ocean tends to be supersaturated with respect to this mineral. Yet, as ambient crystallization inhibitors and active biological 'anti-calcification' prevent physico-chemical precipitation of calcium carbonate, its production depends on the ecological and evolutionary success of the calcifying biota. As the most efficient method to study this intricate process, a series of integrated experimental and modeling studies is proposed, at three levels. Level I studies the general role of calcium carbonate mineralisation in biogeochemical cycling, using microbial mats as the key experimental system. The major calcium carbonate generating biological systems are then studied separately at Level II. Procedures for two of these studies are worked out in some detail, i.e., for coral reefs and coccolithophores. In the former case, selected reef communities are used as model systems, in the second the cosmopolitan species Emiliania huxleyi plays this exemplary role. Finally, at Level III, the results of the previous studies are combined, resulting in a realistic model of the marine calcium carbonate cycle. We suggest that our model systems approach is also applicable to aspects of geosphere-biosphere interactions other than carbonate biogeochemistry.
AN: 3666614
459 of 1521
TI: Demethylation and cleavage of dimethylsulfoniopropionate in marine intertidal sediments
AU: Visscher,-P.T.; Kiene,-R.P.; Taylor,-B.F.
AF: U.S. Geol. Survey-MS 465, 345 Middlefield Rd., Menlo Park, CA 94025, USA
SO: FEMS-MICROBIOL.-ECOL. 1994 vol. 14, no. 2, pp. 179-190
LA: English
ER: M (Marine)
AB: Demethylation and cleavage of dimethylsulfoniopropionate (DMSP) was measured in three different types of intertidal marine sediments: a cyanobacterial mat, a diatom-covered tidal flat and a carbonate sediment. Consumption rates of added DMSP were highest in cyanobacterial mat slurries (59 mu mol DMSP/1 slurry/h) and lower in slurries from a diatom mat and a carbonate tidal sediment (24 and 9 mu mol DMSP/1/h, respectively). Dimethyl sulfide (DMS) and 3-mercaptopropionate (MPA) were produced simultaneously during DMSP consumption, indicating that cleavage and demethylation occurred at the same time. Viable counts of DMSP-utilizing bacteria revealed a population of 2 x 10 super(7) cells/cm super(3) sediment (90% of these cleaved DMSP to DMS, 10% demethylated DMSP to MPA) in the cyanobacterial mat, 7 x 10 super(5) cells/cm super(3) in the diatom mat (23% cleavers, 77% demethylators), and 9 x 10 super(4) cells/cm super(3) (20% cleavers and 80% demethylators) in the carbonate sediment. In slurries of the diatom mat, the rate of MPA production from added 3-methiolpropionate (MMPA) was 50% of the rate of MPA formation from DMSP. The presence of a large population of demethylating bacteria and the production of MPA from DMSP suggest that the demethylation pathway, in addition to cleavage, contributes significantly to DMSP consumption in coastal sediments.
AN: 3665770
460 of 1521
TI: Regeneration of inorganic phosphorus and nitrogen from decomposition of seston in a freshwater sediment
AU: Andersen,-F.O.; Jensen,-H.S.
AF: Dep. Biol., Odense Univ., DK-5230 Odense M, Denmark
SO: HYDROBIOLOGIA 1992 vol. 228, no. 1, pp. 71-81
NT: Spec. Iss.: Sediment-Water Interaction.
LA: English
ER: F (Freshwater)
AB: The mineralization of phosphorus and nitrogen from seston was studied in consolidated sediment from the shallow Lake Arreskov (July and November) and in suspensions without sediment (July). In the suspension experiment, phosphorus and nitrogen were mineralized in the same proportions as they occurred in the seston. During the 30 days suspension experiment, 47 and 43% of the particulate phosphorus and nitrogen, respectively, was mineralized with constant rates. Addition of seston to the sediment had an immediate enhancing effect on oxygen uptake, phosphate and ammonia release, whereas nitrate release decreased due to denitrification. The enhanced rates lasted for 2-5 weeks, while the decrease in nitrate release persisted throughout the experiment. The increase in oxygen uptake (equivalent to 21% of the seston carbon) was, however, only observed in the July experiment. The release of phosphorus and nitrogen from seston decomposing on the sediment surface differed from the suspension experiments. Thus, between 91 and 111% of the phosphorus in the seston was released during the experiments. Due to opposite directed effects on ammonium and nitrate release, the resulting net release of nitrogen was relatively low. A comparison of C/N/P ratios in seston, sediment and flux rates indicated that nitrogen was mineralized faster than phosphorus and carbon. Some of this nitrogen was lost through denitrification and therefore not measurable in the flux of inorganic nitrogen ions. This investigation also suggests that decomposition of newly settled organic matter in sediments have indirect effects on sediment-water exchanges (e.g. by changing of redox potentials and stimulation of denitrification) that modifies the release of mineralized phosphate and nitrogen from the sediment.
AN: 3663821
461 of 1521
TI: Biogeochemical processes in Amazon Shelf sediments
AU: Aller,-R.C.; Aller,-J.Y.; Blair,-N.E.; Mackin,-J.E.; Rude,-P.D.; Stupakoff,-I.; Patchineelam,-S.; Boehme,-S.E.; Knoppers,-B.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794, USA
SO: OCEANOGRAPHY 1991 vol. 4, no. 1, pp. 27-32
LA: English
ER: M (Marine)
AB: Each year the Amazon River delivers approximately 1 billion metric tons of sediment to the equatorial Atlantic. A portion of this debris is highly weathered and contains abundant reactive Fe, Mn, Al, and Si oxides. The associated terrestrial organic matter is biologically refractory. Upon entering the Amazon Shelf region, particles are exposed to seawater brine, mixed with labile planktonic organic matter, and incorporated into the seabed where a variety of geochemical reactions take place. Major research efforts within the AmasSeds Project include elucidating the types and rates of these diagenetic reactions, their governing factors, and their influence on the properties of overlying water and preserved deposits. Modern views of early diagenetic processes in shallow marine sediments have largely derived from studies of temperate estuaries and shelves, particularly along the coasts of North America and Europe. In these environments, sedimentary organic matter is decomposed through the general sequential series of biogeochemical oxidants (O sub(2), NO super(-) sub(3), Mn, Fe, SO super(=) sub(4), CO sub(2)), although reactions are typically dominated over large vertical intervals by sulfate reduction or methanogenesis. Oxygen is often relegated to a largely indirect role as an oxidant of anaerobic metabolites. Other potential oxidants of organic matter such as NO super(-) sub(3), Mn and Fe oxides, are of minor importance. The chemical properties of sediments and patterns of authigenic mineral formation in deposits reflect these reaction paths, as well as diagenetic transport regimes strongly influenced by the bioturbation activities of benthic organisms. In contrast, early studies of Amazon Shelf sediments demonstrated extensive zones of suboxic reactions associated with Fe,Mn reduction and oxidation cycles, and little evidence of macrobenthic activity. Unlike other shelf deposits of similar organic content, sulfate depletion is limited, dissolved sulfide is undetectable, and sulfide minerals are minor in the upper few meters. High concentrations of dissolved Fe super(++) and Mn super(++) in pore water (0.1-1 mM) are found throughout the upper 0.5-2 m of Amazon deposits compared with vertical intervals 0.01-0.05-m thick in many shelves. These suboxic zones extend across the Amazon Shelf for similar to 100 km, encompassing an area of at least 40,000 km super(2) off Brazil alone. Because Fe and Mn oxides and their reduction products are carrier phases for numerous minor and trace elements, their redox cycling can critically influence oceanic chemistry. The input of highly weathered debris and massive physical mobility/reworking of sediments are apparently critical factors determining these patterns. (DBO)
AN: 3663539
462 of 1521
TI: AmasSeds: An interdisciplinary investigation of a complex coastal environment
AU: Nittrouer,-C.A.; DeMaster,-D.J.; Figueiredo,-A.G.; Rine,-J.M.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794, USA
SO: OCEANOGRAPHY 1991 vol. 4, no. 1, pp. 3-7
LA: English
ER: M (Marine)
AB: A multidisciplinary Amazon Shelf SEDiment Study (AmasSeds) is being undertaken on the continental shelf near the mouth of the Amazon River. Details of the AmasSeds international research project are described in the five papers which follow. The present paper outlines the justification, background and approach of the overall project. On the Amazon shelf, between the Para estuary and the Brazil-French Guiana Border, material input and energy expenditure are enormous. This situation produces a myriad of complex interdependent oceanic processes. Sediment is a common link between the diverse processes, because most of them affect and/or are affected by the particles found on the Amazon shelf. The fundamental justification for AmasSeds research is that a number of unique oceanic processes are active near the mouths of very large rivers, and that these processes cannot be understood solely by extrapolation from observations of smaller river systems. For example, the papers which follow will demonstrate that biological productivity and cycling of many geochemical components are largely controlled by the immense discharge of sediment particles. The freshwater discharge of the Amazon displaces typical estuarine circulation from the river mouth into the three-dimensional setting of the shelf, where it is superimposed on marine circulation. Extremely high supply rates of sediment to the Amazon shelf create fluid muds which severely affect marine sediment transport and create an extensive subaqueous delta with special morphologic and stratigraphic character. In addition to being unique, oceanic processes in coastal environments near the mouths of large rivers are very important. They control the fate of the material that is discharged, and in this way affect global budgets. On a worldwide basis, the Amazon discharges 18% of all river water, 10% of fluvial sediment and 8% of dissolved solids. How and whether this material reaches the rest of the world ocean is dependent upon oceanic processes operating on the Amazon shelf. AmasSeds also will provide valuable new insights into some special attributes of the Amazon shelf, such as its location in an equatorial setting. Terrestrial and marine equatorial environments are especially sensitive to world climatic conditions, and the strata preserved at the mouth of the Amazon record the histories of both environments. Chemical weathering in equatorial settings produces lateritic soils and iron-rich sediments, which cause unusual geochemical signatures in the marine portions of the Amazon dispersal system. In addition, important changes to the basic physics of ocean circulation result when river effluent is released at the equator in the absence of Coriolis forces. The Amazon shelf is an ideal study area to investigate the detailed operation of interdisciplinary oceanic processes for reasons described above, and because results from previous research allowed the design of an intricate field and laboratory study. (DBO)
AN: 3663530
463 of 1521
TI: Swimmers: A recapitulation of the problem and a potential solution
AU: Karl,-D.M.; Knauer,-G.A.
SO: OCEANOGRAPHY 1989 vol. 2, no. 1, pp. 32-35
LA: English
ER: M (Marine)
AB: We read, with great interest, the article by Lee et al. (1988) concerning the effects of "swimmers" on the measurement of particulate organic matter flux in the marine environment. Generally swimmers are either: (1) acknowledged and their impact reduced by manually removing the carcasses ("picking") before further sample processing, (2) acknowledged, but trap contents analyzed unaltered, or (3) totally ignored. None of these three options is acceptable, if the desired outcome is to obtain accurate particle flux estimates. As Lee et al. (1988) discuss in their review, the swimmer problem is exacerbated in near-surface waters ( less than or equal to 500 m). Unfortunately, the measurement of particulate organic matter flux in the upper water column is crucial to our understanding of biogenic element cycles, including the rates and mechanisms of nutrient regeneration and, consequently, crucial to addressing the Global Ocean Flux Study (GOFS) program objectives. Because sediment traps are now recognized as the only method for estimating the passive downward flux of organic matter in the sea (SCOR WG-71 report on "Particulate Biogeochemical Processes," S. Krishnaswami, chairman), our progress toward a resolution of these important oceanic processes is stalled at this time. So, to provide a brief answer to the rhetorical question posed in their title, "Are 'Swimmers' a Problem?," we believe the reply is an overwhelming affirmative. (DBO)
AN: 3663177
464 of 1521
TI: Joint Global Ocean Flux Study: The 1989 North Atlantic Bloom Experiment
AU: Ducklow,-H.W.
AF: Horn Point Environ. Lab., Univ. Maryland Cent. Environ. Estuar. Stud., Box 775, Cambridge, MD 21613, USA
SO: OCEANOGRAPHY 1989 vol. 2, no. 1, pp. 4-8
LA: English
ER: M (Marine)
AB: In 1989, JGOFS begins a six-nation, eight month investigation of biogeochemical processes in the North Atlantic Ocean. This experiment will emphasize observation of the spring phytoplankton bloom and its biogeochemical consequences along longitude 20 degree W, between 15 degree and 60 degree N latitude, from March to October. The North Atlantic Bloom Experiment is intended to be a pilot study for future JGOFS experiments. (DBO)
AN: 3663176
465 of 1521
TI: The effect of substrate stoichiometry on microbial activity and carbon degradation in humic lakes
AU: Hessen,-D.O.; Nygaard,-K.; Salonen,-K.; Vaehaetalo,-A.
AF: Univ. Oslo, Dep. Biol., Box 1027 Blindern, N-0315 Oslo, Norway
CO: 4. Nordic Symp. on Humic Substances, Loen (Norway), 7-9 Jun 1993
SO: ENVIRON.-INT. 1994 vol. 20, no. 1, pp. 67-76
LA: English
ER: F (Freshwater)
AB: Studies of bacterial growth and community respiration in water from two humic lakes indicated a balanced supply of C relative to N and P under periods with low loads of allochthonous C (humus). A predominant mineral nutrient limitation existed when external C supply was high. During autumn, both nitrogen and phosphorus additions stimulated bacterial growth, while community respiration was stimulated by N and P combined, but not N alone. Additions of excess labile carbon (glucose) never stimulated either bacterial growth or respiration, while glucose and mineral nutrients combined gave rise to a vigorous production, suggesting that a strict C limitation is unlikely for heterotrophic bacteria in these lakes. Increased anthropogenic loadings of N and P may thus stimulate heterotrophic activity in humic lakes, increase degradation of humic matter, and finally increase CO sub(2) outputs to the atmosphere. A prevailing mineral nutrient limitation of the bacteria would strongly affect the algal-bacterial competition and constrain phytoplankton production.
AN: 3662108
466 of 1521
TI: An ecological perspective on methane emissions from northern wetlands
AU: Bubier,-J.L.; Moore,-T.R.
AF: Dep. Geogr., McGill Univ., 805 Sherbrooke St. W., Montreal, PQ H3A 2K6, Canada
SO: TRENDS-ECOL.-EVOL. 1994 vol. 9, no. 12, pp. 460-464
LA: English
ER: F (Freshwater)
AB: Wetlands are significant sources of atmospheric methane, an important radiatively active "greenhouse" gas that accounts for an estimated 12% of total greenhouse warming. Since global climate models predict the greatest temperature and precipitation changes at high latitudes, and as the largest areas of wetland (346 x 10 super(6) ha) are in the boreal and subarctic regions (40-70 degree N), recent research has focused on identifying the factors that control methane emission from northern wetlands. Over the past few years, the database has expanded tremendously, and much progress has been made in understanding the environmental controls on methane emission at small spatial and temporal scales. However, we now need to broaden our understanding of regional differences in methane emission, ecological responses of northern wetlands to climate change, and the effect of other perturbations such as drainage and flooding.
AN: 3661940
467 of 1521
TI: The production of super(34)S-depleted sulfide during bacterial disproportionation of elemental sulfur
AU: Canfield,-D.E.; Thamdrup,-B.
AF: Sch. Earth and Atmos. Sci., Georgia Inst. Technol., Atlanta, GA 30332, USA
SO: SCIENCE-WASH. 1994 vol. 266, no. 5193, pp. 1973-1975
LA: English
AB: Bacteria that disproportionate elemental sulfur fractionate sulfur isotopes such that sulfate is enriched in sulfur-34 by 12.6 to 15.3 per mil and sulfide is depleted in sulfur-34 by 7.3 to 8.6 per mil. Through a repeated cycle of sulfide oxidation to S super(0) and subsequent disproportionation, these bacteria can deplete sedimentary sulfides in sulfur-34. A prediction, borne out by observation, is that more extensive sulfide oxidation will lead to sulfides that are more depleted in sulfur-34. Thus, the oxidative part of the sulfur cycle creates circumstances by which sulfides become more depleted in sulfur-34 than would be possible with sulfate-reducing bacteria alone.
AN: 3661577
468 of 1521
TI: Problems in the quantitative analysis of submicron particles in marine waters
AU: Ruiz,-J.; Rodriguez,-J.
AF: Fac. Cienc. Mar, Univ. Cadiz, Puerto Real, Cadiz, Spain
CO: NATO Experimental Workshop on the Size Structure and Metabolism of the Marine Microbial Food Web, Malaga (Spain), 25 Jan-5 Feb 1993
SO: THE-SIZE-STRUCTURE-AND-METABOLISM-OF-THE-PELAGIC-ECOSYSTEM. Rodriguez,-J.;Li,-W.K.W-eds. BARCELONA-SPAIN INSTITUTO-DE-CIENCIAS-DEL-MAR 1994 vol. 58, no. 1-2 pp. 81-86
ST: SCI.-MAR.-BARC. vol. 58, no. 1-2
LA: English
ER: M (Marine)
AB: A procedure is described to avoid artifacts due to instabilities when measuring submicron particles (SMP) by mean of resistance pulse instruments (Coulter registered principle). The sample has to flow for at least half an hour before recording the counts given by the equipment. The concentrations of SMP obtained with this procedure are similar to those obtained with image analysis by Sieracki & Viles (1992) but more than one order of magnitude lower than those given by Koike et al. (1990). The discrepancies with the results of Koike et al. (op. cit.) are concentrated in the smallest SMP. Therefore, our results leads us to suggest caution when considering the role of SMP in the biogeochemical cycling of elements in the ocean.
AN: 3661463
469 of 1521
TI: Particle-solution behaviour of plutonium in an estuarine environment, Esk Estuary, UK
AU: Hamilton-Taylor,-J.; Kelly,-M.; Titley,-J.G.; Turner,-D.R.
AF: Cent. Adv. Anal. Chem., Priv. Mail Bag 7, Menai, NSW 2234, Australia
SO: GEOCHIM.-COSMOCHIM.-ACTA 1993 vol. 57, no. 14, pp. 3367-3381
LA: English
ER: B (Brackish)
AB: The particle-solution (K sub(d)) relationships of Pu(III,IV) in the Esk Estuary are investigated, using new experimental data together with a synthesis of our earlier work. Adsorption of super(236)Pu(IV) by a suspension of intertidal mud (40 mg/L) from the Esk Estuary was determined after 1 h, as a function of salinity and pH, in a series of controlled laboratory experiments. Desorption of super(239,240)Pu(III,IV) from this environmentally contaminated sediment was determined concurrently. The short term (i.e., within a tidal cycle) non-conservative behaviour of Pu(III,IV) in both the laboratory experiments and the estuary appears to be dominated by a rapid, reversible surface complexation reaction, although only a small fraction (<5%) of the super(239,240)Pu(III,IV) activity of the environmentally contaminated sediment is able to participate in the reaction. The existence of this exchangeable or labile fraction can explain the apparent dependence of Pu(III,IV) K sub(d) on sediment concentration. Thus, a single K sub(d) value is able to describe both the observed adsorption and desorption behaviour and the effect of sediment concentration, when desorption is expressed with respect to the labile super(239,240)Pu(III,IV) fraction. For example, in R. Esk water, the adsorption of super(236)Pu(III,IV) and the desorption of super(239,240)Pu(III,IV), over a two order of magnitude concentration range of unwashed Esk Estuary sediment, can be accounted for by a single K sub(d) of similar to 3 x 10 super(3) L/kg. The K sub(d) for the labile Pu(III,IV) fraction varies mainly as a function of salinity. pH is not an important factor over the pH range 4-9, although H super(+) ion exchange does occur, probably through a similar surface complexation reaction. The kinetic and equilibrium characteristics of the Pu(III,IV) sorption behaviour conform to the pattern observed by Jannasch et al. (1988) and other workers for a range of trace elements.
AN: 3661288
470 of 1521
TI: Seasonal and geographic variations of methanesulfonic acid in the Arctic troposphere
AU: Li,-S.-M.; Barrie,-L.A.; Talbot,-R.W.; Harriss,-R.C.; Davidson,-C.I.; Jaffrezo,-J.-L.
AF: Atmos. Environ. Serv., 4905 Dufferin St., Downsview, ON, Canada
SO: ATMOS.-ENVIRON.,-PART-A 1993 vol. 27A, no. 17-18, pp. 3011-3024
NT: Special Issue: Arctic Air, Snow and Ice Chemistry.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Measurements in the Arctic troposphere over several years show that MSA concentrations in the atmospheric boundary layer, 0.08-6.1 parts per trillion (ppt, molar mixing ratio), are lower than those over mid-latitude oceans. The seasonal cycle of MSA at Alert, Canada (82.5 degree N, 62.3 degree W), has two peaks of 6 ppt in March-April and July-August and minima of 0.3 ppt for the rest of the year. At Dye 3 (65 degree N, 44 degree W) on the Greenland Ice Sheet, a similar seasonal MSA cycle is observed although the concentrations are much lower with a maximum of 1 ppt. Around Barrow, Alaska (71.3 degree N, 156.8 degree W), MSA is between 1.0 and 25 ppt in July, higher than 1.5 plus or minus 1.0 ppt in March-April. The mid-tropospheric MSA level of 0.6-1 ppt in the summer Arctic is much lower than about 6 ppt in the boundary layer. At Alert, the ratio of MSA to non-sea-salt (nss) SO sub(4) super(2-) ranges from 0.02 to 1.13 and is about 10 times higher in summer than in spring. The summer ratios are higher than found over mid-latitude regions and, when combined with reported sulfur isotope compositions from the Arctic, suggest that on average a significant fraction (about 16-23%) of Arctic summer boundary layer sulfur is marine biogenic. The measurements show that the summer Arctic boundary layer has a significantly higher MSA/nss-SO sub(4) super(2-) ratio than aloft.
AN: 3660466
471 of 1521
TI: Chemosynthetic bacterial mats at cold hydrocarbon seeps, Gulf of Mexico continental slope
AU: Sassen,-R.; Roberts,-H.H.; Aharon,-P.; Larkin,-J.; Chinn,-E.W.; Carney,-R.
AF: Geochem. Environ. Res. Gr., Texas A&M Univ., College Station, TX 77845, USA
SO: ORG.-GEOCHEM. 1993 vol. 20, no. 1, pp. 77-89
LA: English
AB: White and pigmented filamentous bacterial mats dominated by several undescribed species of Beggiatoa were sampled during research submersible dives to cold hydrocarbon seep sites on the upper continental slope off Louisiana (130-550 m). Mats occur at the interface between reducing sediments and the oxygenated water column. They are localized at sea floor features related to seepage of biogenic methane and crude oil, but there is little evidence that the organisms utilize the hydrocarbons directly. Granules of elemental sulfur (S super(0)) are visible within cells of Beggiatoa, and mat material is characterized by high contents of S super(0) (up to 193,940 ppm). The Beggiatoa biomass is isotopically light ( delta super(13)C = -27.9ppt PDB). Our geochemical data suggest that the Beggiatoa species are part of a complex bacterial assemblage in cold seep sediments. They oxidize H sub(2)S derived from the bacterial sulfate reduction that accompanies bacterial hydrocarbon oxidation when O sub(2) is depleted in sediments, and fix isotopically light carbon from CO sub(2) that is the result of bacterial hydrocarbon oxidation. Beggiatoa mats appear to retard loss of hydrocarbons to the water column by physically retaining fluids in sediments, a function that could enhance production by other bacteria of the H sub(2)S and CO sub(2) needed by Beggiatoa.
AN: 3660462
472 of 1521
TI: Degradation of organic matter by several size fractions of plankton from the lower Dniester River and the Dniester Estuary
AU: Potapova,-N.A.
AF: Inst. Hydrobiol., Ukrainian Acad. Sci., Kiev, Ukraine
SO: HYDROBIOL.-J.;GIDROBIOL.-ZH. 1994;1993 vol. 30, no. 3, pp. 13-24;vol. 29, no. 2, pp. 12-22
LA: English
ER: B (Brackish); F (Freshwater)
AB: The picoplankton fraction (0.2-2.0 mu m) and the nannoplankton (2.0-4.0 mu m), consisting chiefly of bacteria, play the dominant role in the degradation of organic matter in the waters of the lower Dniester River and the Dniester estuary. The oxygen uptake by these organisms in the absence of larger planktonic organisms is comparable with that of whole water (which has not been filtered to separate the fractions) and exceeds that of whole water in about 25 percent of the cases.
AN: 3658493
473 of 1521
TI: Transfer of mercury between the atmosphere and lake or soil surfaces
AU: Xiao,-Z.F.; Munthe,-J.; Schroeder,-W.H.; Lindqvist,-O.
CA: Goeteborg Univ., (Sweden). Dep. of Inorganic Chemistry
SO: 1990 4 pp
NT: NTIS Order No.: N90-26419/3/GAR.
LA: English
ER: F (Freshwater)
AB: A flux chamber technique for the measurement of volatile mercury species is described. It is used to measure the direction and magnitude of the flux of mercury over lake and soil surfaces. Measurements carried out over four oligotrophic lakes with different mercury concentrations in their fish as well as different humic contents are described. The measuring apparatus is outlined and described. The measurements are concluded to be reasonably reliable. Significant diurnal and large seasonal variations in surface emission fluxes of vapor phase mercury are found in the waters from the four Swedish forest lakes. (DBO)
AN: 3657764
474 of 1521
TI: Calcification, photosynthesis, and global carbon cycles
AU: McConnaughey,-A.
AF: U.S. Geol. Survey, Box 25046, MS 413, Denver, CO 80225-0046, USA
CO: Past and Present Biomineralization Processes. Considerations about the Carbonate Cycle. IUCN-COE Workshop, Monaco (Monaco), 15-16 Nov 1993
SO: PAST-AND-PRESENT-BIOMINERALIZATION-PROCESSES.-CONSIDERATIONS-ABOUT-THE-CARBONATE-CYCLE.-IUCN-COE-WORKSHOP,-MONACO-MONACO,-15-16-NOVEMBER-1993. Doumenge,-F.;Allemand,-D.;Toulemont-A.-eds. MONACO-MONACO MUSEE-OCEANOGRAPHIQUE 1994 no. Spec. Iss. 13 pp. 137-161
ST: BULL.-INST.-OCEANOGR.-MONACO no. Spec. Iss. 13
LA: English
ER: M (Marine)
AB: Photosynthetic carbon uptake from natural waters can induce calcification, but more commonly with aquatic plants and algae- invertebrate symbioses, calcification functionally precedes the photosynthetic utilization of bicarbonate. In this capacity, calcification generates protons, which are used to convert bicarbonate to carbon dioxide. Organisms which rely on this physiology tend to calcify in approximately 1:1 molar ratio to photosynthesis, in mildly alkaline, calcium rich waters such as the oceans. The use of calcification as a proton generator constitutes one of the most important adaptations to aquatic photosynthesis and probably accounts for most of the calcification which occurs globally. Because calcification counteracts the alkalinization and carbon dioxide depletion which accompanies photosynthesis, variations in the global rates of calcification influence aquatic and atmospheric carbon dioxide levels. Over phanerozoic timescales, calcification by photosynthetic organisms has played a major role in converting most of the carbon in the biosphere into limestone.
AN: 3656146
475 of 1521
TI: Symbiosis, calcification, and environmental interactions
AU: Buddemeier,-R.W.
AF: Kansas Geol. Surv., Univ. Kansas, Lawrence, KS 66047, USA
CO: Past and Present Biomineralization Processes. Considerations about the Carbonate Cycle. IUCN-COE Workshop, Monaco (Monaco), 15-16 Nov 1993
SO: PAST-AND-PRESENT-BIOMINERALIZATION-PROCESSES.-CONSIDERATIONS-ABOUT-THE-CARBONATE-CYCLE.-IUCN-COE-WORKSHOP,-MONACO-MONACO,-15-16-NOVEMBER-1993. Doumenge,-F.;Allemand,-D.;Toulemont-A.-eds. MONACO-MONACO MUSEE-OCEANOGRAPHIQUE 1994 no. Spec. Iss. 13 pp. 119-135
ST: BULL.-INST.-OCEANOGR.-MONACO no. Spec. Iss. 13
LA: English
ER: M (Marine)
AB: Enhancement of calcification by algal symbiosis is important to our understanding of evolution and the geologic record, contemporary ecology and biogeochemical cycles, and the potential future effects of human alteration of the global carbon cycle. Recent trends in coral reef research have oversimplified the diversity of algal symbiosis and largely ignored the potential effects of inorganic chemical controls on calcification at all scales. This paper describes and justifies a revised conceptual framework for the investigation of biocalcification and its symbiotic enhancement, with particular emphasis on coral reef issues.
AN: 3656143
476 of 1521
TI: Phosphorus dynamics following restoration measures in the Loosdrecht Lakes (The Netherlands)
AU: Van-Liere,-L.; Gulati,-R.D.; Wortelboer,-F.G.; Lammens,-E.H.R.R.
AF: Limnol. Inst., Rijksstraatweg 6, 3631 AC, Netherlands
CO: Int. Symp. on Trophic Relationships in Inland Waters, Tihany (Hungary), 1-4 Sep 1987
SO: TROPHIC-RELATIONSHIPS-IN-INLAND-WATERS. Biro,-P.;Talling,-J.F.-eds. 1990 vol. 191 pp. 87-95
ST: HYDROBIOLOGIA vol. 191
LA: English
ER: F (Freshwater)
AB: External phosphorus loads to three shallow lakes in the Netherlands were reduced by eliminating waste-water discharge and by dephosphorization of the supply water, with which water level is controlled. Concentrations of total-phosphorus and chlorophyll a were significantly reduced during 1980-1986 in L. Breukeleveen, but not in L. Vuntus and L. Loosdrecht. In 1983-1986 the phosphorus flow through several trophic levels was determined. Changes over these years were not significant. External input to the lakes still contributes substantially to the phosphorus input. Release from the sediments also contributed to the cycling of the phosphorus. Excretion by large crustacean zooplankters was important in phosphorus recycling, and delivered 20-30% of the daily phytoplankton phosphorus demand. A similar contribution is expected from fish. If one wants recovery of the lakes to be accelerated, additional measures are needed. (DBO)
AN: 3655624
477 of 1521
TI: Exchange of phosphorus across the sediment-water interface
AU: Bostroem,-B.; Andersen,-J.M.; Fleischer,-S.; Jansson,-M.
AF: Dep. Limnol., Uppsala Univ., Box 557, S-751 22 Uppsala, Sweden
CO: Phosphorus in Freshwater Ecosystems, Uppsala (Sweden), 25-28 Sep 1985
SO: PHOSPHORUS-IN-FRESHWATER-ECOSYSTEMS. Persson,-G.;Jansson,-M.-eds. 1988 vol. 170 pp. 229-244
ST: HYDROBIOLOGIA vol. 170
LA: English
ER: F (Freshwater)
AB: In this article, principles of phosphorus retention and phosphorus release at the sediment-water interface in lakes are reviewed. New results and hypotheses are discussed in relation to older models of phosphorus exchange between sediments and water. The fractional composition of sedimentary phosphorus is discussed as a tool for interpretation of different retention mechanisms. Special emphasis is given to the impact of biological, particularly microbial, processes on phosphorus exchange across the sediment-water interface and to the significance of biologically induced CaCO sub(3) precipitation to phosphorus retention in calcareous lakes. (DBO)
AN: 3655607
478 of 1521
TI: The sulfur cycle of freshwater sediments: Role of thiosulfate
AU: Jorgensen,-B.B.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark
SO: LIMNOL.-OCEANOGR. 1990 vol. 35, no. 6, pp. 1329-1342
LA: English
ER: B (Brackish); F (Freshwater)
AB: The formation and pathways of thiosulfate (S sub(2)O sub(3) super(2-)) in anoxic sediment were studied in the Odder River and Brabrand Lake, Denmark. Time-course experiments were done in slurries with four super(35)S tracers: SO sub(4) super(2-), H sub(2)S, and S sub(2)O sub(3) super(2-) with either the inner (oxidized) or the outer (reduced) S atom labeled. The two sediments gave similar results. Of all the S sub(2)O sub(3) super(2-) consumed in Brabrand Lake sediment, 6% was oxidized, 50% was reduced, and 44% was disproportionated. S sub(2)O sub(3) super(2-) disproportionation is an inorganic fermentation in certain SO sub(4) super(2-)-reducing bacteria by which the inner and outer S atoms are simultaneously transformed into SO sub(4) super(2-) and sulfide, respectively. Altogether, 28% of the S sub(2)O sub(3) super(2-)-S was converted into SO sub(4) super(2-) and 72% was converted into sulfide. S sub(2)O sub(3) super(2-) inhibited SO sub(4) super(2-) reduction by 75%. The immediate products of anoxic sulfide oxidation were 34% SO sub(4) super(2-) and 66% S sub(2)O sub(3) super(2-). Half of the oxidized sulfide was ultimately converted into SO sub(4) super(2-) and half was recycled back to sulfide via S sub(2)O sub(3) super(2-). Two-thirds of the S in the sulfide-thiosulfate "minicycle" remained at an oxidation state of -2. S sub(2)O sub(3) super(2-) is thus a key intermediate in the S cycle, both as a main product of anoxic sulfide oxidation and as a shunt between oxidative and reductive pathways.(DBO)
AN: 3655581
479 of 1521
TI: Ammonium recycling limits nitrate use in the oceanic subarctic Pacific
AU: Wheeler,-P.A.; Kokkinakis,-S.A.
AF: Coll. Oceanogr., Oregon State Univ., Corvallis, OR 97331-5503, USA
SO: LIMNOL.-OCEANOGR. 1990 vol. 35, no. 6, pp. 1267-1278
LA: English
ER: M (Marine)
AB: Seasonal and diel changes in nutrient concentrations and nitrogen assimilation rates were used to assess the effects of NH sub(4) super(+) on NO sub(3) super(-) assimilation. Surface-water NO sub(3) super(-) concentrations ranged from 6 to 17 mu M while NH sub(4) super(+) concentrations ranged from 0 to 0.4 mu M. Total N assimilation ranged from 84 to 732 nM/d but showed no seasonal trend. NH sub(4) super(+) and urea concentrations were <1% of total dissolved inorganic N, but use of this "regenerated" N still accounted for 44-89% of total N assimilation. Rates of NO sub(3) super(-) assimilation were negatively correlated with ambient NH sub(4) super(+) concentrations, and concentrations of NH sub(4) super(+) between 0.1 and 0.3 mu M caused complete inhibition of NO sub(3) super(-) assimilation. NO sub(3) super(-) was more important as a source of N in spring than in summer. We attribute this pattern to a summer increase in turnover rates for NH sub(4) super(+). Turnover times for the dissolved NH sub(4) super(+) pool were half as long in August as in May. Grazing and recycling in the euphotic zone apparently both play significant roles in preventing depletion of NO sub(3) super(-) in the oceanic subarctic Pacific. (DBO)
AN: 3655579
480 of 1521
TI: Implications of high dissolved organic matter concentrations for oceanic properties and processes
AU: Jackson,-G.A.
AF: Inst. Mar. Resour., Scripps Inst. Oceanogr., La Jolla, CA 92093, USA
SO: OCEANOGRAPHY 1988 vol. 1, no. 2, pp. 28-33
LA: English
ER: M (Marine)
AB: It has recently been argued that the dominant forms of reduced oceanic nitrogen and carbon may be overlooked by traditional techniques used to measure dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). Suzuki et al. (1985) and Sugimura and Suzuki (1988) have reported that concentrations of DOC and DON in the ocean are 2 to 5 times those measured with previous techniques. Williams and Druffel (1988) have discussed the measurement issues and their implications for the nature of dissolved organic carbon in the sea. In this article, some of the implications of the new DOC and DON values for oceanic biology and chemistry are examined. (DBO)
AN: 3655148
481 of 1521
TI: The measurement of oceanic particle flux - Are "swimmers" a problem?
AU: Lee,-C.; Wakeham,-S.G.; Hedges,-J.I.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: OCEANOGRAPHY 1988 vol. 1, no. 2, pp. 34-36
LA: English
ER: M (Marine)
AB: About 10 years ago, the use of sediment traps to measure oceanic particle fluxes and composition began to proliferate. This technique has now become widespread. Research on particle composition and flux using sediment-trap and other large-particle sampling technologies has clearly shown the importance of particulate matter in global biogeochemical cycles. It has become a major goal within the oceanographic community to understand the processes controlling particle production, transport and destruction on both small and large scales. Particularly important to these studies is an accurate estimate of particle production and flux in surface waters. Initially, sediment traps were used to collect particles without careful regard to in-situ bacterial decay of material in the traps. As it became clear that organic material in particles could be significantly degraded during the two-week and longer periods over which traps were deployed, poisons and preservatives became more commonly used to prevent decomposition. Typical poisons currently used are HgCl sub(2) and NaN sub(3), while common preservatives are formalin and salt. We are currently investigating the effectiveness of these and other compounds in preventing decomposition and alteration of particulate organic compounds collected in sediment traps. However, with the use of poisons and preservatives, another potentially more significant bias is introduced to sediment trap collections. This is the collection of "swimmers": zooplankton and other marine animals that swim into the trap and die. Under some circumstances, particularly in shallow traps placed in coastal areas, much of the material collected can be swimmers. We observed this in trap samples collected in the California Current during the VERTEX V experiments. (VERTEX was a multidisciplinary study of VERtical Transport and EXchange of material in the upper ocean.) Even in deeper or less productive waters, swimmers can be present in trap samples. (DBO)
AN: 3655147
482 of 1521
TI: Methane oxidation activity in various soils and freshwater sediments: Occurrence, characteristics, vertical profiles, and distribution on grain size fractions
AU: Bender,-M.; Conrad,-R.
AF: Max-Planck-Inst. Terrestrische Mikrobiol., Marburg, FRG
SO: J.-GEOPHYS.-RES.-D-ATMOS. 1994 vol. 99, no. 8, pp. 16531-16540
LA: English
ER: F (Freshwater)
AB: CH sub(4) oxidation activities from various soils and freshwater sediments were measured at low ( less than or equal to 2 parts per million by volume (ppmv)) and high ( greater than or equal to 1000 ppmv) CH sub(4) mixing ratios. Most of the tested soils acted as sinks for atmospheric CH sub(4). A correlation between the CH sub(4) oxidation activity and the numbers of methanotrophs was only observed at high (1000 ppmv) CH sub(4) mixing ratios. This indicates that the counted methanotrophs were not the bacteria which are oxidizing atmospheric CH sub(4) ( less than or equal to 1.7 ppmv). The CH sub(4) oxidation was due to prokaryotic microorganisms active only under oxic conditions. The CH sub(4) oxidation activity decreased at O sub(2) mixing ratios below 1-3% and was rather insensitive for the variation of O sub(2) at mixing ratios >3%. Undisturbed, stratified soils, and freshwater sediments showed vertical profiles of CH sub(4) oxidation activities with a distinct maximum. Sediments showed an exact correspondence between the number of methanotrophs and the maximum of CH sub(4) oxidation both being localized at the surface sediment layer. The oxic soils showed maxima of CH sub(4) oxidation activities generally located in subsurface layers. The maxima of CH sub(4) oxidation activities were slightly shifted below the maxima of the numbers of methanotrophs indicating that the counted bacteria (incubation under 20% CH sub(4)) might not represent the active population which oxidizes atmospheric CH sub(4). Plowed, agricultural soils showed no distinct maxima, neither of the CH sub(4) oxidation activities nor of the numbers of methanotrophs. The grain size fractionation by centrifugation or wet sieving of slurries of two forest soils showed that the bulk (80-96%) of the CH sub(4) oxidizing activity was attached to the smaller mineral fractions (clay, silt, fine sand) of these soils. Within the mineral fractions, greater particles had higher specific activities of CH sub(4) oxidation than smaller particles.
AN: 3654389
483 of 1521
TI: Historical evolution of the Southwest Florida coastline and its effect on adjacent marine environments
AU: Frederick,-B.C.; Gelsanliter,-S.; Risi,-J.A.; Wanless,-H.R.
AF: Geol. and Geophys., Rosenstiel Sch. Mar. Atmos. Sci., 4600 Rickenbacker Causeway, Miami, FL 33149, USA
CO: Symp. on Florida Keys Regional Ecosystem, Miami, FL (USA), Nov 1992
SO: SYMPOSIUM-ON-FLORIDA-KEYS-REGIONAL-ECOSYSTEM.-NOVEMBER-1992. Prospero,-J.M.;Harwell,-C.C.-eds. 1994 vol. 54, no. 3 pp. 1074-1075
ST: BULL.-MAR.-SCI. vol. 54, no. 3
NT: Abstract only.
LA: English
ER: M (Marine)
AB: An examination of historical aerial photography (1928-present) reveals three significant types of change in the coastal/wetland environment on the southwest coast of Florida between Cape Sable and Chatham River: coastal erosion, erosion of shorelines and islands in larger interior bays, and landward expansion of mangrove communities. There are two types of coastal erosion. Progressive erosion from winter storms has affected significant portions of this west-facing coastline. Hurricane surges penetrating tidal creek complexes have created local patches of catastrophic erosion within the wetland environment. Coastlines and islands within larger interior bays are eroding, especially along the north and east shores. This erosion has resulted from both recurrent winter storm waves and episodic hurricane scour. Eroded sediment is largely organic and is oxidized, dissolved or transported out of the system. Shore erosion within bays has resulted in the expansion of tidal prisms and in the enlargement of channels connecting to the offshore marine environment. During the past 52 years of historical records, some mangrove community boundaries have remained relatively stable while others have dramatically expanded across adjacent transitional and freshwater marshes. As much as 86 meters of landward expansion is recognized. Mangrove community expansion occurs by both episodic, storm-generated seedling introduction and progressive expansion. Gently sloping coastlines provide a setting to record the temporary advance of infringing mangrove communities in this wetland coastal landscape. Erosion of these coastlines is providing a significant volume of dissolved and particulate organics and nutrients into adjacent mangrove, transitional, and freshwater wetlands and into the adjacent marine environments. Organics and nutrients discharged into coastal marine waters are pulsed southward by winter storms into Florida Bay and the Florida Keys. Future global warming, with increased rates of sea-level rise and increased frequency of hurricanes, should dramatically increase rates of erosion of this wetland coastline and increase the importance of this area as a source for organic and nutrient discharge.
AN: 3654097
484 of 1521
TI: The ocean's role in global change: Progress of major research programs
CA: National Research Counc., Washington, DC (USA). Ocean Studies Board
SO: WASHINGTON,-DC-USA NATIONAL-ACADEMY-PRESS 1994 85 pp
LA: English
ER: M (Marine)
AB: During the past decade, the debate about whether Earth's climate is changing has intensified. Global - or even regional - climate shifts will have far-reaching implications for world economics, energy utilization, national defense, and the health of terrestrial and marine ecosystems. Although the role of the ocean in global climate is not fully understood, there is general agreement that it is significant. Climate models predict that increases in greenhouse gases may lead to significant regional and possibly global climate changes. The scientific community has initiated large-scale research programs based on studies of the ocean and its relation to global climate and climate related processes. This report, which describes the research programs, is divided into two main sections: programs that study processes that occur over periods ranging from days to hundreds of years - the contemporary system; and those that seek to understand long-term variations ranging from thousands to millions of years - the geological perspective. Some programs have both long- and short-term elements. A third section discusses crosscutting data-collection issues important to all programs.
AN: 3654090
485 of 1521
TI: An apparent contradiction in the role of phosphorus in Cenozoic chemical mass balances for the World Ocean
AU: Delaney,-M.L.; Filippelli,-G.M.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA, USA
SO: PALEOCEANOGRAPHY 1994 vol. 9, no. 4, pp. 513-527
LA: English
ER: M (Marine)
AN: 3653863
486 of 1521
TI: Accumulation of Th, Pb, U, and Ra in marine phytoplankton and its geochemical significance
AU: Fisher,-N.S.; Teyssie,-J.-L.; Krishnaswami,-S.; Baskaran,-M.
AF: Oceanogr. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: LIMNOL.-OCEANOGR. 1987 vol. 32, no. 1, pp. 131-142
LA: English
ER: M (Marine)
AB: The bioaccumulation of U, Th, Ra, and Pb in four diverse nanoplanktonic algal species and a picoplanktonic blue-green alga was determined with radiotracers. Among the nanoplankton, differences of 1-2 orders of magnitude in volume/volume concentration factors (VCFs) were observed for a given nuclide, but larger differences were observed among the four nuclides, with VCF values of Th > Pb > Ra greater than or less than U. The picoplankton cells, with greater surface: volume ratios, had significantly higher VCF values. The mean VCF values in the nanoplankton of Th and Pb were 1.5 x 10 super(5) and 3.6 x 10 super(4) in the light and 2.8 x 10 super(5) and 7.3 x 10 super(4) in the dark. The VCFs of Th and Pb in the picoplankton were both about 2 x 10 super(6), irrespective of light. Retention half-times of super(228)Th and super(210)Pb in fecal pellets of Artemia salina, fed radiolabeled diatoms, were 20-50 d, but >120 d for super(228)Th at 4 degree C. The results suggest that sinking plankton and their debris could account for most of the natural series radionuclides sedimenting out of oceanic surface waters. (DBO)
AN: 3652005
487 of 1521
TI: Hydrogen distributions in marine sediments
AU: Novelli,-P.C.; Scranton,-M.I.; Michener,-R.H.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794, USA
SO: LIMNOL.-OCEANOGR. 1987 vol. 32, no. 3, pp. 565-576
LA: English
ER: M (Marine)
AB: Hydrogen concentrations have been measured in sulfate-reducing sediments of a British Columbian fjord and in Skan Bay, Alaska, as well as in the hemipelagic sediments of the eastern north tropical Pacific off the Mexican coast. In the sediments of both the Mexican shelf and Canadian fjord, hydrogen levels were lowest near the surface, increased with depth and reached a maximum pore-water concentration of about 25-35 nM before sulfate was totally depleted. Deeper in the sediments, H sub(2) levels decreased again. In Skan Bay sediments, concentrations of pore-water hydrogen increased almost linearly with depth to a maximum level of 60 nM. Measured rates of hydrogen production in Skan Bay sediments varied little with depth (about 200 nM/d), and in Skan Bay the hydrogen pool had a turnover time of, at most, several hours. Model-predicted net rates of hydrogen production in Skan Bay are not significantly different than zero. These results are consistent with the hypothesis of interspecies hydrogen transfer between hydrogen-producing and -consuming bacterial populations, which predicts low ambient hydrogen concentrations and tight coupling between production and consumption. (DBO)
AN: 3651967
488 of 1521
TI: Dynamics of seston constituents in the Ariege and Garonne rivers (France)
AU: Chauvet,-E.; Fabre,-A.
AF: Cent. Ecol. des Ressour. Renouvelables, C.N.R.S., 29 rue Jeanne Marvig, 31055 Toulouse Cedex, France
SO: HYDROBIOLOGIA 1990 vol. 192, no. 2-3, pp. 183-190
LA: English
ER: F (Freshwater)
AB: Water contents of suspended matter, algal pigments, particulate organic carbon and particulate phosphorus were measured in the rivers Garonne (2 sites) and Ariege (1 site) throughout an annual cycle. The general trend of the parameters was similar at the three sites. Depending on the sites, the period of algal growth (chlorophyll a + phaeopigments > 25 mu g/l), lasted from two to six weeks in August-September. The algal peaks reached 50 to 90 mu g/l of total pigments. High contents of particulate organic carbon (> 2 mg/l) occurred at the end of summer (coinciding with algal growth), and during the November and May floods. In summer 50-75% of the suspended matter was organic, in spring this was 10 times less. The high linear correlation between particulate organic carbon and pigment contents (r = 0.87; P = 0.0001) suggested an algal origin of at least part of the particulate carbon. Algal carbon was minor in the annual fluxes of particulate carbon (25 to 39% depending on the sites), but relatively high in comparison with other rivers. The mean particulate phosphorus content calculated over the year was 24 mu g/l; it varied from 15 mu g/l during the high water period to 28 mu g/l during the low water period. Likewise the percentage of particulate phosphorus in the suspended matter varied from 0.17 to 0.40. A negative linear correlation existed between particulate phosphorus content and specific discharge (r = -0.46; P = 0.0001). The very marked seasonal trend of the parameters and the interactions led us to differentiate two modes of the rivers' functioning: a 'hydrologic' phase and a 'biological' phase. The hydrologic phase (high water) was dominated by the processes of erosion and transfer over the whole catchment area and the flood plain, while the biological phase was characterized by a high primary production in the river bed. (DBO)
AN: 3651589
489 of 1521
TI: Towards a joint global ocean flux study: Rationale, objectives, planning, implementation
AU: De-Baar,-H.J.W.; Van-Aken,-H.M.; Fransz,-H.G.; Ganssen,-G.M.; Gieskes,-W.W.C.
CA: Nederlands Inst. voor Onderzoek der Zee, Texel (Netherlands)
SO: 1988 59 pp
NT: NTIS Order No.: PB91-142901/GAR.
RN: NIOZ-1988-14 (NIOZ198814)
LA: English
ER: M (Marine)
AB: The oceanic inventories and fluxes of carbon are of major importance for the global C cycle in past, present and future. The global scale of the problem and the intricate interactions between physical, biological, and chemical forces warrant both an international and a truly multidisciplinary approach. Objective of the ICSU/SCOR/JGOFS program is 'To determine and understand on a global scale the time varying fluxes of carbon and associated biogenic elements in the ocean, and to evaluate the related exchanges with the atmosphere, the sea floor and continental boundaries'. Planning for 1989-1999 is focusing on (1) Process studies in selected areas; (2) Time Series observations to be continued or newly started; (3) Global Survey largely through satellite observation. The merits of selected study areas in regions as the Antarctic Ocean, the Pacific Basin, the Northwest Indian Ocean and the North Atlantic Ocean are being exploited. Implementation is now well underway with the North Atlantic Pilot Study where ships from six countries participate in a study of the temporal and spatial shifts of C fluxes related to the spring and autumn plankton blooms. (DBO)
AN: 3651499
490 of 1521
TI: Are wetlands the key to the ice-age cycle enigma?
AU: Franzen,-L.G.
AF: Dep. Phys. Geogr., Goeteborg Univ., Reutersgatan 2C, S-413 20 Gothenburg, Sweden
SO: AMBIO 1994 vol. 23, no. 4-5, pp. 300-308
LA: English
ER: F (Freshwater)
AB: The Vostok record of carbon dioxide (CO sub(2)) and methane (CH sub(4)) indicates that these greenhouse gases play a decisive role in the glacial/interglacial interplay during the Quaternary. A new theory presented here suggests that the ice-age cycles are generated by the peat growth in temperate wetlands. Glaciations on the other hand are believed to be responsible for the successive transformation of landscapes into types suitable for wetland initiation. In this respect, comparisons between the global distribution of wetlands with areas subjected to glaciation during ice ages shown a remarkable correspondence. If the theory presented here is correct, with the rapidly increasing concentrations of, e.g. CO sub(2) from anthropogenic sources, we are only at the beginning of an incomparable interglacial epoch.
AN: 3651429
491 of 1521
TI: Comparison of the kinetics of ferrous iron oxidation by three different strains of Thiobacillus ferrooxidans
AU: Chavarie,-C.; Karamanev,-D.; Godard,-F.; Garnier,-A.; Andre,-G.
AF: Dep. Genie Chim., Ec. Polytech. Montreal, P.O. Box 6079, Succ. A, Montreal, PQ H3C 3A7, Canada
SO: GEOMICROBIOL.-J. 1993 vol. 11, no. 1, pp. 57-63
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Three different strains of Thiobacillus ferrooxidans were grown in aqueous ferrous sulfate solutions at 30.5 degree C and at pH 2.0 in a bioreactor. Their specific growth rate followed Monod kinetics. Their maximum specific growth rate ( mu sub(m)) was between 0.138 and 0.148/h and their saturation constant (K sub(s)) was in the range from 0.338 to 0.479 g Fe super(2+)/L. Comparing our data with other data from the literature, we concluded that the kinetics of ferrous iron oxidation is independent of the strain used. A good approximation of the growth kinetics on ferrous iron of Thiobacillus ferrooxidans between 20 and 32 degree C and pH 2.0-2.5 is obtained by using mu sub(m) = 0.14/h K sub(s) = 0.4 g Fe super(2+)/L.
AN: 3651367
492 of 1521
TI: Significance of sedimentation for the termination of Phaeocystis blooms
AU: Wassmann,-P.
AF: Norwegian Coll. Fish. Sci., Univ. Tromso, N-9037 Tromso, Norway
CO: Workshop on the Ecology of Phaeocystis-dominated Ecosystems, Brussels (Belgium), Jan 1991
SO: J.-MAR.-SYST. 1994 vol. 5, no. 1, pp. 81-100
LA: English
ER: M (Marine)
AB: The role of sedimentation for the termination of Phaeocystis blooms is exemplified through case studies from the literature as well as from anecdotal evidence. Scenarios of high and low sedimentation following Phaeocystis blooms exist. Mass sedimentation was found in the Barents Sea and the Ross Sea, but vertical flux below the euphotic zone was insignificant in a north Norwegian fjord and the Weddell Sea. In general, no regular and recurring pattern of sedimentation events can be expected during Phaeocystis blooms. Factors influencing the fate of senescent Phaeocystis blooms are probably water depth, turbulent energy supply, aggregate formation, release of flagellated cells from colonies, microbial degradation, zooplankton grazing as well as lysis of colonies and cells. The role sedimentation plays for the termination of Phaeocystis blooms seems to be determined by the physical and biological characteristics of the specific ecosystem where the bloom occurs. In general, Phaeocystis-dominated ecosystems tend to endorse pelagic rather than benthic mineralization.
AN: 3650770
493 of 1521
TI: Microbial populations of hydrothermal fluid and plumes in the North Fiji Basin with reference to chemosynthesis
AU: Naganuma,-T.; Seki,-H.
AF: Deep Sea Res. Dep., Japan Mar. Sci. and Technol. Cent. (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237, Japan
SO: MAR.-GEOL. 1994 vol. 116, no. 1-2, pp. 243-253
NT: Special issue: North Fiji Basin: STARMER French-Japanese Program.
LA: English
ER: M (Marine)
AB: Bacterioplankton abundance of the hydrothermal plumes in the North Fiji Basin (NFB) was anomalously high in bottom waters at several sampling stations. Good correlation between the manganese concentration and the bacterial viable counts was found for the bottommost waters. Sulfur bacterial strains, supposedly major chemosynthetic microorganisms associated with hydrothermal activity, were isolated from the bottommost water. The bacterial population growth and the CO sub(2)-uptake by the sulfur bacterial strains suggested the sulfur bacteria in the plumes were facultatively autotrophic. Also, a sulfur bacterial strain from the hydrothermal fluid was shown to be thermophilic-eurybaric. Biogeochemical roles of the planktonic sulfur bacteria in the hydrothermal area were pointed out as: (1) a food source to filter-feeders of the vent fauna; and (2) a possible first settler of the hydrothermal ecosystems.
AN: 3650709
494 of 1521
TI: Trace element distributions in some saline lakes of the Vestfold Hills, Antarctica
AU: Masuda,-N.; Nakaya,-S.; Burton,-H.R.; Torii,-T.
AF: Dep. Chem., Fac. Fish. Sci., Hokkaido Univ., Hakodate-city, Japan 041
SO: BIOLOGY-OF-THE-VESTFOLD-HILLS,-ANTARCTICA. Ferris,-J.M.;Burton,-H.R.;Johnstone,-G.W.-eds.;Bayly,-I.A.E.-eds. 1988 vol. 165 pp. 103-114
ST: HYDROBIOLOGIA vol. 165
LA: English
ER: M (Marine)
AB: The distributions of trace elements in Shield, Ace and Burton Lakes of the Vestfold Hills were investigated. Three aspects are discussed as follows: (1) the vertical distribution of 18 trace elements in the three lakes, (2) the behaviour of trace elements in the lakes, especially that of manganese in Shield Lake, and (3) the origin of trace elements in antarctic saline lakes. High concentrations of trace elements were found in these coastal saline lakes, when compared to open ocean water. We suggest that the peak of total extractable manganese, found at 20 m in Shield Lake, was related to the oxic/anoxic water interface brought about by microbiological activity. Solid phase manganese at the upper oxic layer may have precipitated and then reached the anoxic boundary to be there reduced to manganese ion. This dissolved manganese may then have diffused upwards to be reoxidized to a solid form. This cycle, repeated many times, may have produced the Mn profile. The alkali, alkaline earth elements and Cl were probably derived from relict seawater. Other elements were present in similar concentration ratios to those of South Polar aerosols. Residence time calculations indicate that fallout of aerosol particles, themselves derived from various sources, is capable of accounting for the measured concentrations of some trace elements in Shield Lake. This source of trace elements may be significant for other antarctic saline lakes. (DBO)
AN: 3648417
495 of 1521
TI: Iodine distribution in an antarctic meromictic saline lake
AU: Butler,-E.C.V.; Burton,-H.R.; Smith,-J.D.
AF: CSIRO Mar. Lab., Div. Oceanogr., GPO Box 1538, Hobart, Tas. 7001, Australia
SO: BIOLOGY-OF-THE-VESTFOLD-HILLS,-ANTARCTICA. Ferris,-J.M.;Burton,-H.R.;Johnstone,-G.W.-eds.;Bayly,-I.A.E.-eds. 1988 vol. 165 pp. 97-101
ST: HYDROBIOLOGIA vol. 165
LA: English
ER: B (Brackish)
AB: Water samples collected from a range of depths in Ace Lake in the Vestfold Hills, Antarctica were analysed for iodine species by a polarographic method. Contrary to thermodynamic prediction, iodide was the predominant species in oxic surface waters. Total dissolved iodine was closely correlated with bacterial density down the water column. This observation and other data are used to postulate a scheme for the biological mediation of iodine distribution in the lake. (DBO)
AN: 3648416
496 of 1521
TI: Mangrove forests and faecal rain
AU: Chow,-B.A.; Bacon,-P.R.
AF: Univ. West Indies, Mona, Jamaica
SO: CARIBB.-MAR.-STUD. 1992 vol. 3, pp. 57-58
LA: English
ER: M (Marine)
AB: The findings are presented of studies conducted in Oyster Bay, an estuarine lagoonal site on the north coast of Jamaica with fringe Rhizophora to determine the importance of Aratus pisonii frass (the animal component of litter-fall) in the energy flow pathway in the mangrove forest ecosystem. The rhythmic daily feeding migration of A. pisonii up into the canopy results in the presence of Aratus faecal pellets in the Rhizophora litter production. Faecal pellets and other small frass components immediately into the detrital pool, in contrast to plant litter which undergoes a lengthy fragmentation and mineralization process.
AN: 3648316
497 of 1521
TI: Export of biogenic carbon to fish and to the deep ocean: The role of large plankton microphages
AU: Fortier,-L.; Le-Fevre,-J.; Legendre,-L.
AF: Dep. Biol., Univ. Laval, Ste-Foy, PQ G1K 7P4, Canada
SO: J.-PLANKTON-RES. 1994 vol. 16, no. 7, pp. 809-839
LA: English
ER: M (Marine)
AB: The turnover time of biogenic carbon in the ocean can be defined as the time elapsed between the photosynthetic uptake of dissolved inorganic carbon and the return of this carbon as CO sub(2) in surface waters of the atmosphere. Three compartments can be defined: short-lived carbon (< 10 super(-2) year), long-lived carbon (10 super(-2)-10 super(2) years) and carbon sequestered in deep water or sediments. Pelagic organisms that package small particles into larger ones lengthen the turnover time of biogenic carbon and, in some cases, transfer the carbon from a given compartment to a longer-lived one. The lengthening of turnover time should be a direct function of the ratio between the size of organisms and that of their food particles. Under some circumstances, large species of euphausiids and copepods, in the North Pacific and the Southern Ocean, contribute to the lengthening of carbon turnover time. However, the most efficient re-packagers of small particles into larger ones are salps, appendicularians, doliolids and thecosome pteropods, which feed on particles at least 3.5 orders of magnitude smaller than their own size. It is hypothesized that the capacity of these large microphages to swim explosively allows them to control phytoplankton blooms and prevent the development of particle concentrations that could clog their filtering apparatus. Salps, appendicularians and, to some degree, thecosome pteropods are frequent in the diet of some larval and adult fish, and thus contribute to some extent to the direct transformation of short-lived microbial carbon into longer-lived harvestable resources. Yet, the main ecological role of large non-crustacean microphages may reside in the production of fast-sinking, resistant, faecal pellets (in particular those of oceanic salps) that often make up the bulk of the vertical flux of organic material into deep waters, where biogenic carbon can be sequestered for long periods.
AN: 3648242
498 of 1521
TI: Benthic phosphorus regeneration, net primary production, and ocean anoxia: A model of the coupled marine biogeochemical cycles of carbon and phosphorus
AU: Van-Cappellen,-P.; Ingall,-E.D.
AF: Sch. Earth Atmos. Sci., Georgia Inst. Technol., Atlanta, GA, USA
SO: PALEOCEANOGRAPHY 1994 vol. 9, no. 5, pp. 677-692
LA: English
ER: M (Marine)
AB: We examine the relationships between ocean ventilation, primary production, water column anoxia, and benthic regeneration of phosphorus using a mass balance model of the coupled marine biogeochemical cycles of carbon (C) and phosphorus (P). The elemental cycles are coupled via the Redfield C/P ratio of marine phytoplankton and the C/P ratio of organic matter preserved in marine sediments. The model assumes that on geologic timescales, net primary production in the oceans is limited by the upwelling of dissolved phosphorus to the photic zone. The model incorporates the dependence on bottom water oxygenation of the regeneration of nutrient phosphorus from particulate matter deposited at the water-sediment interface. Evidence from marine and lacustrine settings, modern and ancient, demonstrates that sedimentary burial of phosphorus associated with organic matter and ferric oxyhydroxides decreases when bottom water anoxia-dysoxia expands. Steady state simulations show that a reduction in the rate of thermohaline circulation, or a decrease of the oxygen content of downwelling water masses, intensifies water column anoxia-dysoxia and at the same time increases surface water productivity. The first effect reflects the declining supply of oxygen to the deeper parts of the ocean. The second effect is caused by the enhanced benthic regeneration of phosphorus from organic matter and ferric oxyhydroxides. Sedimentary burial of organic carbon and authigenic calcium phosphate mineral (francolite), on the other hand, is promoted by reduced ocean ventilation. According to the model, global-scale anoxia-dysoxia leads to a more efficient recycling of reactive phosphorus within the ocean system. Consequently, higher rates of primary production and organic carbon burial can be achieved, even when the continental supply of reactive phosphorus to the oceans remains unchanged.
AN: 3646144
499 of 1521
TI: Microcommunities and microgradients: Linking nutrient regeneration, microbial mutualism, and high sustained aquatic primary production
AU: Wetzel,-R.G.
AF: Dep. Biol. Sci., Univ. Alabama, Tuscaloosa, AL 35487-0344, USA
SO: NETH.-J.-AQUAT.-ECOL. 1993 vol. 27, no. 1, pp. 3-9
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Nutrient regeneration is essential to sustained primary production in the aquatic environment because of coupled physical and metabolic gradients. The commonly evaluated ecosystem perspective of nutrient regeneration, as is illustrated among planktonic paradigms of lake ecosystems, functions only at macro-temporal and spatial scales. Most inland waters are small and shallow. Consequently, most organic matter of these waters is derived from photosynthesis of emergent, floating-leaved, and submersed higher plants and microflora associated with living substrata and detritus, including sediments, as well as terrestrial sources. The dominant primary productivity of inland aquatic ecosystems is not planktonic, but rather is associated with surfaces. The high sustained rates of primary production among sessile communities are possible because of the intensive internal recycling of nutrients, including carbon. Steep gradients exist within these attached microbial communities that (a) require rapid, intensive recycling of carbon, phosphorus, nitrogen, and other nutrients between producers, particulate and dissolved detritus, and bacteria and protists; (b) augment internal community recycling and losses with small external inputs of carbon and nutrients from the overlying water or from the supporting substrata; and (c) encourage maximal conservation of nutrients. Examples of microenvironmental recycling of carbon, phosphorus, and oxygen among epiphytic, epipelic, and epilithic communities are explained. Recalcitrant dissolved organic compounds from decomposition can serve both as carbon and energy substrates as well as be selectively inhibitory to microbial metabolism and nutrient recycling. Rapid recycling of nutrient and organic carbon within micro-environments operates at all levels, planktonic as well as attached, and is mandatory for high sustained productivity.
AN: 3646141
500 of 1521
TI: Release rates of trace elements and protein from decomposing planktonic debris. 1. Phytoplankton debris
AU: Lee,-B.-G.; Fisher,-N.S.*
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: J.-MAR.-RES. 1993 vol. 51, no. 2, pp. 391-421
LA: English
ER: M (Marine)
AB: The release rates of Ag, Am, Cd, Ce, Co, Pb, Se and Zn from decomposing diatom cells were determined using gamma-emitting radiotracers; rates were compared with C and protein loss rates over time. Additionally, experiments were designed to evaluate various artifacts involved in the experimental use of radioisotopes, handling of biogenic debris, and the use of poisons. The release rates of C at 18 degree C exponentially decreased with time from 17.5% d super(-1) at 1 d to 2.7% d super(-1) at 6 d; those of protein slowed from 9.2% d super(-1) at 1 d to 2.0% d super(-1) at 6 d. Rates at 18 degree C were 2-4 times faster than rates at 4 degree C. Rate changes at both temperatures were much less pronounced from 6-25 d. Retention half-times (t sub(r1/2)s) of Ag, Am, Ce, Co and Pb in diatom debris were significantly greater than those of Cd, Se and Zn under the same conditions; t sub(r1/2) values decreased inversely with temperature. The t sub(r1/2) values of C and protein were generally comparable to those of Cd, Se and Zn, whereas the ratios of the other metals to C and protein increased significantly over time. Microbial activity very strongly enhanced Co scavenging onto decaying particles in the dark. The elemental loss rate data suggest that Cd, Se and Zn should generally follow the fate of organic C and protein in decomposing planktonic debris. These elements should be biologically recycled and have longer residence times in surface waters than the other metals which are more particle-reactive and which do not follow organic C and protein release.
AN: 3645577
501 of 1521
TI: The ecological significance of bacterial reduction of sulfate in bottom sediments of the Dnieper-Bug lagoon
AU: Samoylenko,-V.N.; Golovko,-T.V.
AF: Inst. Hydrobiol., Ukrainian Acad. Sci., Kiev, Ukraine
SO: HYDROBIOL.-J.;GIDROBIOL.-ZH. 1994;1993 vol. 30, no. 5, pp. 105-110;vol. 29, pp. 85-94
LA: English
ER: B (Brackish)
AB: The development of anaerobic zones and the bacterial reduction of sulfate ion in the Dnieper-Bug Lagoon were studied. The basic precondition for sulfate reduction is the presence of readily decomposable organic matter. When the rate of sulfate reduction exceeds 100 mg S super(2-)/m super(2)-day, both sulfate dissolved in the water and sulfate in the interstitial water of the sediments becomes involved in the process. The development of anaerobic zones causes a sharp deterioration of oxygen conditions and slows the decomposition of organic matter to one-half to one-fourth the original rate.
AN: 3645474
502 of 1521
TI: The possible involvement of methylcobalamin in the production of methyl iodide in the marine environment
AU: Manley,-S.L.
AF: Dep. Biol. Sci., California State Univ., 1250 Bellflower Blvd., Long Beach, CA 90840, USA
SO: MAR.-CHEM. 1994 vol. 46, no. 4, pp. 361-369
LA: English
ER: M (Marine)
AB: Methyl iodide (CH sub(3)I) is a biogenic iodocarbon of marine and estuarine waters, and is an important component in the biogeochemical cycling of iodine. A possible significant abiotic marine source of CH sub(3)I is the reaction of methylcobalamin (CH sub(3)-B sub(12)) with either iodide or molecular iodine (I sub(2)) in seawater. These reactions were shown to occur in seawater and buffered water. The reaction between iodide and CH sub(3)-B sub(12) was apparently second order. The pH had a slight but significant effect on the reaction rate at pH between 7 and 8, and a more pronounced effect at a pH < 7. Chloride, bromide, iodate and bicarbonate had no significant effects on CH sub(3)I production at the standard reaction pH of 8.5. Iodate in the reaction mixture did not affect the reaction rate at pH > 7.5, however, at pH < 7.5 the presence of iodate increased the rate of CH sub(3)I production (9 fold at pH 5) due to the probable formation of I sub(2). The addition of aquocobalamin to the reaction mixture (CH sub(3)-B sub(12) + iodide) enhanced CH sub(3)I production (63% at pH 5; 38% at pH 8.5) presumably by catalyzing the oxidation of iodide to I sub(2). Molecular iodine also reacted with CH sub(3)-B sub(12) to form CH sub(3)I. The separate addition of CH sub(3)-B sub(12), I super(-) or I sub(2) to coastal seawater, for a final concentration of 0.22 mM, 4.8 mM and 25 mu M, respectively, resulted in the detectable formation of CH sub(3)I. The significance of these reactions to the formation CH sub(3)I in the oceans is discussed.
AN: 3644929
503 of 1521
TI: Formation of volatile sulfides in freshwater environments
AU: Caron,-F.; Kramer,-J.R.
AF: Waste Manage. Syst., At. Energy Canada Ltd., Chalk River Lab., Chalk River, ON K0J IJ0, Canada
SO: SCI.-TOTAL-ENVIRON. 1994 vol. 153, no. 3, pp. 177-194
LA: English
ER: F (Freshwater)
AB: Organic Volatile Sulfides (OVS) of biogenic origin are ubiquitous in the environment and are an important contributor to the global atmospheric sulfur cycle. We show that OVSs are widespread in the freshwater environment. The species H sub(2)S, COS, CS sub(2), methanethiol (MeSH), dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) have been found in samples of freshwater and in freshwater algal cultures. A few C sub(2)-C sub(4) alkylated sulfur species were found, of which only 1-propanethiol was identified, but they were detected in less than 10% of the samples or cultures. No sulfide species predominates in freshwaters, unlike the case of DMS in marine waters. Freshwater algal cultures were grown under laboratory conditions using various sulfur sources and methyl donors. Sulfate concentrations did not influence the production of OVS, but L-methionine was key in the production of methylated sulfides. The other sulfur-containing amino acids (cysteine, cystine) did not influence the production of OVS. Methyl donors did not significantly affect OVS production, except for CH sub(3)I, which induced higher levels of methylated sulfides with Oscillatoria sp. We did not find any factor that affected the production of H sub(2)S, COS and CS sub(2).
AN: 3643963
504 of 1521
TI: Late Quaternary CaCO sub(3) production and preservation in the Southern Ocean: Implications for oceanic and atmospheric carbon cycling
AU: Howard,-W.R.; Prell,-W.L.
AF: Education Assoc., Woods Hole, MA, USA
SO: PALEOCEANOGRAPHY 1994 vol. 9, no. 3, pp. 453-482
LA: English
ER: M (Marine)
AN: 3641601
505 of 1521
TI: The formation of apatite from crab faecal pellets
AU: Simkiss,-K.; Taylor,-M.G.
AF: Dep. Pure and Appl. Zool., Univ. Reading, Reading, RG6 2AJ, UK
SO: J.-MAR.-BIOL.-ASSOC.-U.K. 1994 vol. 74, no. 2, pp. 459-462
LA: English
ER: M (Marine)
AB: Intracellular granules have been isolated from the digestive gland of the shore crab Carcinus maenas (L.). These granules are normally shed from this tissue during the digestive cycle and are shown to occur in considerable numbers in the faecal strands. The granules are amorphous to x-ray diffraction and remain in this state in sea-water for several weeks, although they will transform into crystalline apatite in simpler saline solutions. The fate of these deposits in the marine environment is discussed in relation to their contribution to sediments and phosphorites.
AN: 3638874
506 of 1521
TI: Recent calcium carbonate dissolution in the Barents Sea: Paleoceanographic applications
AU: Steinsund,-P.I.; Hald,-M.
AF: Dep. Geol., IBG, Univ. Tromsoe, N-9037 Tromsoe, Norway
SO: MAR.-GEOL. 1994 vol. 117, no. 1-4, pp. 303-316
LA: English
ER: M (Marine)
AB: Studies of benthic foraminifera in surface sediments of the Arctic, epicontinental Barents Sea, show several indications of calcium carbonate dissolution. Low values of calcium carbonate correspond to low ratios of calcareous/agglutinating foraminifera, planktic/benthic foraminifera, high ratios of living/dead foraminifera, corroded calcareous foraminifera, and high numbers of exposed organic linings of foraminifera. Dissolution increases eastwards and northwards in the study area. We suggest that the dissolution is caused by the presence of dense, cold, saline and CO sub(2)-rich bottom water, which is linked to sea-ice production and the position of the Oceanic Polar Front. We also think calcium carbonate dissolution in this area indicates a sink for atmospheric CO sub(2).
AN: 3638838
507 of 1521
TI: Nitrogen uptake, dissolved organic nitrogen release, and new production
AU: Bronk,-D.A.; Glibert,-P.M.; Ward,-B.B.
AF: Dep. Marine Sci., Univ. Georgia, Athens, GA 30602, USA
SO: SCIENCE-WASH. 1994 vol. 265, no. 5180, pp. 1843-1852
LA: English
ER: M (Marine); B (Brackish)
AB: In oceanic, coastal, and estuarine environments, an average of 25 to 41 percent of the dissolved inorganic nitrogen (NH sub(4) super(+) and NO sub(3) super(-)) taken up by phytoplankton is released as dissolved organic nitrogen (DON). Release rates for DON in oceanic systems range from 4 to 26 nanogram-atoms of nitrogen per liter per hour. Failure to account for the production of DON during nitrogen-15 uptake experiments results in an underestimate of gross nitrogen uptake rates and thus an underestimate of new and regenerated production. In these studies, traditional nitrogen-15 techniques were found to underestimate new and regenerated production by up to 74 and 50 percent, respectively. Total DON turnover times, estimated from DON release resulting from both NH sub(4) super(+) and NO sub(3) super(-) uptake, were 10 plus or minus 1, 18 plus or minus 14, and 4 days for oceanic, coastal, and estuarine sites, respectively.
AN: 3638660
508 of 1521
TI: Trace gas emissions from Canadian peatlands and the effect of climatic change
AU: Moore,-T.R.
AF: Dep. Geogr., McGill Univ., 805 Sherbrooke St. W, Montreal, PQ H3A 2K6, Canada
SO: WETLANDS 1994 vol. 14, no. 3, pp. 223-228
LA: English
ER: F (Freshwater)
AB: The emission of three trace gases, nitrous oxide, carbon dioxide, and methane, from peatlands is examined, identifying the primary controls and the potential effect of climatic change on emission rates. Nitrous oxide emission from natural peatlands is small and tied to the cycling of nitrogen but increases upon disturbance such as drainage. Peatlands generally act as a sink for carbon dioxide, but they convert from a sink to a source upon drainage. Methane emissions are controlled primarily by position of the water table, with secondary controls of temperature and trophic status of the peat. Canadian and other northern peatlands play a moderately important role in the global methane budget. Climate change, such as increases in temperature and precipitation predicted by 2 x CO sub(2) scenarios, may result in increased emissions of nitrous oxide, decreased carbon dioxide storage, and reduced methane emissions from Canadian peatlands.
AN: 3635612
509 of 1521
TI: The future of research in Canadian peatlands: A brief survey with particular reference to global change
AU: Gorham,-E.
AF: Dep. Ecol., Evol. and Behav., Univ. Minnesota, St. Paul, MN 55108, USA
SO: WETLANDS 1994 vol. 14, no. 3, pp. 206-215
LA: English
ER: F (Freshwater)
AB: Suggestions are made for future research on Canadian peatlands under several headings: distribution across the country, landscape features, environmental factors (hydrology, microclimatology, perma-frost, and fire), ecosystem properties (productivity, decomposition, biogeochemical cycling, and microbial activity), biotic characteristics (flora and fauna, including rare and threatened species), and paleoecological background. This evaluation points out the need for studies of peatland restoration. In addition, it is important to follow present models of excellence for future study and to train a new generation of researchers in multidisciplinary research.
AN: 3635610
510 of 1521
TI: (Interconnected research 'Case Study Harz': Pollutant burden, reaction of the ecosphere, and water quality. Final reports).
OT: Verbundforschung Fallstudle Harz: Schadstoffbelastung, Reaktion der Oekosphaere und Wasserqualitaet. Abschlussberichte
CA: Goettingen Univ. (FRG). Forschungszent. Waldoekosysteme-Waldsterben
SO: 1990 230 pp
LA: German
ER: F (Freshwater)
AB: The interconnected research 'Case Study Harz' investigates interdisciplinary questions of pollutant burden, mechanisms of deposition, reactions of the ecosphere and the resulting water quality in the catchment areas under observation. The increasing acidification of waters leads to a mobilization of heavy metals from existing lake sediments through extraction of cations. Against the background of a geochemical and hydrochemical survey and documentation, linkages in the field of action of pollutant deposition, pollutant transport and the effect of pollutants on aquatic biological communities are investigated and standards for action required in the future are assessed. Particularly important are questions of the relevance and informative value of biological indicators (Overall record from three individual records). (JH). [Contracts BMFT 0339069A, BMFT 0339069B. In German. Berichte des Forschungszentrums Waldoekosysteme. Reihe B, v. 19.] (DBO)
AN: 3633624
511 of 1521
TI: Simulation analysis of moored fluorometer time series from the Mid-Atlantic Bight during 1987-1990
AU: Walsh,-J.J.
CA: South Florida Univ., St Petersburg (USA). Dep. of Marine Science
SO: REP.-U.S.-DEP.-ENERGY 1990 42 pp
RN: DOE/ER/60285-4 (DOEER602854)
LA: English
ER: M (Marine)
AB: The goal of the previous research during 1987-1990 within the DOE (Department of Energy) Shelf Edge Exchange Processes (SEEP) program in the Mid-Atlantic Bight was to understand the physical and biogeochemical processes effecting the diffusive exchange of the proxies of energy-related, by-products associated with particulate matter between estuarine, shelf, and slope waters on this continental margin. As originally envisioned in the SEEP program plan, SEEP-III would take place at Cape Hatteras to study the advective exchange of materials by a major boundary current. One problem of continuing interest is the determination of the local assimilative capacity of slope waters and sediments off the eastern seaboard of the US to lengthen the pathway between potentially harmful energy by-products and man. At basin scales, realistic specification of the lateral transport by western boundary currents of particulate matter is a necessary input to global models of carbon/nitrogen cycling. Finally, at these global scales, the generic role of continental margins in cycling greenhouse gases, e.g. CO(sub 2), CH(sub 4), and N(sub 2)O, is now of equal interest. This continuing research of model construction and evaluation within the SEEP program focuses on all three questions at local, regional, and basin scales. Results from SEEP-I and II are discussed as well as plans for SEEP-III. [Contract FG05-85ER60285 Sponsored by Department of Energy, Washington, DC. Portions of this document are illegible in microfiche products.] (DBO)
AN: 3633609
512 of 1521
TI: Precipitation of carbonate minerals by microorganisms: Implications for silicate weathering and the global carbon dioxide budget
AU: Ferris,-F.G.; Wiese,-R.G.; Fyfe,-W.S.
AF: Dep. Geol., Univ. Toronto, 22 Russell ST., Toronto, ON M5S 3B1, Canada
SO: GEOMICROBIOL.-J. 1994 vol. 12, no. 1, pp. 1-13
LA: English
ER: B (Brackish); F (Freshwater)
AB: Direct light and electron microscopic studies show that cyanobacterial cells serve as nucleation sites for carbonate mineral precipitation in a variety of fresh to saline-alkaline lakes on the Cariboo Plateau in central British Columbia, Canada, and in mineralized crusts on weathered basalt in Iceland. The carbonate minerals found in association with the cyanobacteria were extremely fine-grained, and invariably occurred on the external surfaces of the cells. Carbonate mineralogy was variable, ranging from calcite to magnesite, depending on differences in lake and groundwater chemistry (i.e., saturation state of the water with respect to individual carbonate minerals). In microcosm experiments, phototrophic cyanobacterial increased alkalinity and the degree of oversaturation with respect to calcite. Calculated values for the saturation state of calcite and magnesite in Cariboo Plateau natural waters exhibited two distinct trends, with (1) high magnesite saturation values in areas where the weathering of magnesium olivine-rich basalt bedrock determines water chemistry, and (2) high calcite saturation values where bedrock is a mix of basic lava flows, limestone, argillite, and chert. Similar calculations for Iceland show that cold surface waters are generally oversaturated with respect to calcite, as expected for the weathering of calcium plagioclase-rich larva. These observations of microbial carbonate precipitation in the Caribou Plateau region of British Columbia, Canada, and on the Budarhaun larva plain in Iceland suggest that weathering of silicate minerals in bedrock is biogeochemically coupled to the deposition of carbonate minerals by microorganisms. This process may provide a sink for atmospheric carbon dioxide in terrestrial environments.
AN: 3632683
513 of 1521
TI: Release rates of trace elements and protein from decomposing planktonic debris. 2. Copepod carcasses and sediment trap particulate matter
AU: Reinfelder,-J.R.; Fisher,-N.S.*; Fowler,-S.W.; Teyssie,-J.-L.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: J.-MAR.-RES. 1993 vol. 51, no. 2, pp. 423-442
LA: English
ER: M (Marine)
AB: In experiments designed to relate the release kinetics of various elements with that of protein from biogenic particles, super(110m)Ag, super(241)Am, super(109)Cd, super(60)Co, super(75)Se and protein were measured over time in radiolabeled copepod carcasses and particles caught in unpoisoned sediment traps (mostly zooplankton fecal pellets and amorphous marine snow). Log-linear release rate constants (k) of super(110m)Ag, super(241)Am, super(109)Cd, and super(60)Co from carcasses ranged from 0.079/d for super(60)Co at 2 degree C to 0.130/d for super(109)Cd at 15 degree C, and did not vary significantly with temperature. super(75)Se was lost most rapidly from copepod carcasses at 2 degree C, with k = 0.168/d; however, at 15 degree C, super(75)Se was in two compartments, with 56% in a rapidly exchanging pool (k = 0.391/d) and 44% in a slowly exchanging pool (k = 0.107/d). Protein displayed loss from two compartments at both temperatures. At 2 degree C, protein was lost slowly (k = 0.065/d) for 1 wk, after which it was released from the carcasses very rapidly (k = 0.245/d). At 15 degree C, however, the loss of protein from carcasses was more rapid over the first 2 d (k = 0.627/d) than thereafter (k = 0.127/d).
AN: 3632674
514 of 1521
TI: Cadmium versus phosphate in the world ocean
AU: de-Baar,-H.J.W.; Saager,-P.M.; Nolting,-R.F.; van-der-Meer,-J.
AF: Netherlands Inst. Sea Res., P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: MAR.-CHEM. 1994 vol. 46, no. 3, pp. 261-281
LA: English
ER: M (Marine)
AB: Cadmium (Cd) is one of the best studied trace metals in seawater and at individual stations exhibits a more or less linear relation with phosphate. The compilation of all data from all oceans taken from over 30 different published sources into one global dataset yields only a broad scatterplot of Cd versus phosphate. However, the smaller high-quality dataset obtained by rigorous selection of only those stations with uniform Cd/PO sub(4)-ratio in the deep waters, provides a consistent global description of the deep (> 1000 m) waters. The deep Cd/PO sub(4)-ratio increases from about 0.18 x 10 super(-3) in the subarctic North Atlantic to about 0.33-0.35 x 10 super(-3) in the northern Indian and Pacific Oceans, in accordance with increasing phosphate content, i.e. age, of the deep water. The increasing Cd/PO sub(4)-ratio with age (and phosphate) of the deep water masses is a function of the coupling between biogeochemical cycling and deep water circulation. Changes in the latter, for example during a glacial period, inevitably lead to significant shifts in the Cd/PO sub(4) relationship of seawater. Currently, the global distribution of the Cd/PO sub(4)-ratio in surface, thermocline and deep waters is consistent with preferential biogeochemical removal of Cd versus phosphate from surface waters. The net result for Cd/PO sub(4) is not dissimilar to the preferential surface removal of super(12)C over super(13)C driving the deep distribution of the dissolved super(12)C/ super(13)C-ratio, although for Cd/PO sub(4) the underlying mechanism is obviously very different and not well understood.
AN: 3632524
515 of 1521
TI: Level and fate of trace metals in the Lagoon of Venice (Italy)
AU: Martin,-J.-M.; Huang,-Wei-Wen; Yoon,-Yi-Yong
AF: Inst. Biogeoch. Mar., URA-CNRS 386, Ec. Norm. Super., 1, Rue Maurice Arnoux, F-92120 Montrouge, France
SO: MAR.-CHEM. 1994 vol. 46, no. 4, pp. 371-386
LA: English
ER: M (Marine)
AB: This paper presents the first results of dissolved (total concentration and hydrophobic fraction) and particulate trace metals (core sediment and suspended matter) in the Lagoon of Venice. Both the particulate and dissolved trace metal concentrations are comparable with those measured in pristine rivers and non-contaminated seawater. In the mixing zone between the Silone channel water and the Adriatic seawater, Pb, Zn, Ni, Fe and Cd behave conservatively, indicating the absence of any significant removal or mobilization processes, Cu is significantly released from the particulate to the dissolved form. The mobilization of Cu is associated with the intense production of macroalgae and phytoplankton in the lagoon. The C18 Sep-Pak column extraction method has been used to isolate the hydrophobic organic fraction of dissolved trace metals. This fraction increases in the following order: Cd, Pb < Fe < Zn < Ni < Cu. A first estimate of total dissolved trace metals input to the lagoon of Venice shows that the atmospheric fluxes are more important than the riverine one's for all studied trace metals.
AN: 3630885
516 of 1521
TI: Iron photochemistry in seawater from the Equatorial Pacific
AU: Johnson,-K.S.; Coale,-K.H.; Elrod,-V.A.; Tindale,-N.W.
AF: Moss Landing Mar. Lab., P.O. Box 450, Moss Landing, CA 95039, USA
SO: MAR.-CHEM. 1994 vol. 46, no. 4, pp. 319-334
LA: English
ER: M (Marine)
AB: The photochemistry of iron in surface waters, and its implications to iron bioavailability, was examined on two cruises to the equatorial Pacific. Decktop incubations were performed with equatorial seawater to which iron was added in various chemical forms. Results showed clear diurnal patterns in measurable iron levels, with the highest levels occurring midday. These results are consistent with a model of iron cycling involving the photo-reductive dissolution of colloidal iron and its subsequent oxidation and biological uptake of dissolved iron(III). Model calculations were based on independently determined rate constants. We suggest that photochemical reactions may have a significant impact on iron availability to phytoplankton in the open ocean.
AN: 3630843
517 of 1521
TI: Increased coccolith production by coccolithophorid algae cultures enriched with dissolved inorganic carbon
AU: Takano,-H.; Takei,-R.; Manabe,-E.; Burgess,-J.G.; Matsunaga,-T.
AF: Tokyo Univ. Agric. and Technol., Koganei, Tokyo 184, Japan
CO: 3. International Marine Biotechnology Conference, Tromsoe, Norway, 7-12 Aug 1994
SO: 3RD-INTERNATIONAL-MARINE-BIOTECHNOLOGY-CONFERENCE:-PROGRAM,-ABSTRACTS-AND-LIST-OF-PARTICIPANTS. International-Advisory-Comm.-of-the-Int.-Marine-Biotechnology-Conference-1994,-Tromsoe-Norway TROMSOE-NORWAY TROMSOE-UNIVERSITY 1994 p. 50
LA: English
ER: M (Marine)
AB: Coccolithophorids are unicellular planktonic marine algae which produce elaborate structures called coccoliths which consist of scales or plates of CaCO sub(3). Coccoliths are made from calcium ions and bicarbonate ions present in sea water by the coccolithophorid algae. These ions are present in seawater as a result of lime stone and silicate stone weathering. Huge blooms of coccolithophorid algae often occur in the world's oceans and are an important aspect of the global carbon cycle and the recycling of CaCO sub(3). We have chosen coccolithoporid algae as model organisms to investigate biomineralization and have focussed on the ecological significance of CaCO sub(3) recycling. To determine of the biological factors limiting coccolith formation by Emiliania huxleyi, we investigated the effect of bicarbonate and calcium ion concentrations on coccolith formation. We demonstrated that enrichment of Eppley's medium with dissolved inorganic carbon (DIC) affected both coccolith formation (calcification) and cell growth (photosynthesis). Coccolith formation was enhanced to a greater extent than cell growth. Moreover, high-density culture of E. huxleyi was carried out by supplying sufficient DIC, calcium ions and nutrients to the cells. A maximum yield of coccolith particles of 0.61 g/l per day was obtained.
AN: 3630187
518 of 1521
TI: Biogeochemical transformations of nitrogen and phosphorus -- a pelagic submodel for the Baltic Sea
AU: Savchuk,-O.; Wulff,-F.
AF: State Oceanogr. Inst., St. Petersburg Branch, 23d Line, 2A, 199026, St. Petersburg, Russia
SO: SYST.-ECOL.-CONTRIB. 1993 no. 1, 50 pp
LA: English
ER: M (Marine); B (Brackish)
AB: A sub-model of the biogeochemical processes that drive the nitrogen and phosphorus cycles in the pelagic ecosystem of the Baltic Sea has been developed. It includes four levels of ecosystem structure - inorganic, organic, autotrophic, and heterotrophic variables and descriptions of physical, chemical and biological processes. The numerical experiments show plausible behaviour as well as reasonable reactions to changes in the parameters and in the driving forces, considering the constraint of a submodel. Our conclusion from this sub model development is that we have now created a basic structure describing the pelagic transformations of both nitrogen and phosphorus, useful in an overall model of the biogeochemical cycles of these elements in the Baltic. However, these processes of the pelagic community are intimately coupled to physical events and interactions with the sediments are of utmost importance in the shallow Baltic. Therefore, further development of the model must first include an integration with hydrodynamic and sediment submodels and then the addition of certain critical processes (nitrogen fixation, phosphate sorption-desorption).
AN: 3627899
519 of 1521
TI: Enzymatic models for estimating decomposition rates of particulate detritus
AU: Sinsabaugh,-R.L.; Osgood,-M.P.; Findlay,-S.
AF: Biol. Dep., Univ. Toledo, Toledo, OH 43606, USA
SO: J.-N.-AM.-BENTHOL.-SOC. 1994 vol. 13, no. 2, pp. 160-169
LA: English
ER: F (Freshwater)
AB: The authors evaluated a new statistical method that estimates POM mass loss rates from indices of microbial enzyme activity. Litter bags containing benthic POM in three size ranges--Fine (F) 0.063-0.25 Medium (M) 0.25-1 and Coarse (C) 1-4 mm--were placed in a eutrophic woodland stream in June 1992. Over a 6-mo period, samples were collected and analyzed for mass loss and the activities of seven extracellular enzymes involved in the degradation of holocellulose, chitin, and polyphenolic compounds. In-situ POM samples were collected concurrently and assayed for the same suite of enzyme activities. In all cases, mass loss was related to cumulative enzyme activity; however, apparent enzymatic degradation efficiencies were generally lower for MPOM and EPOM (= MFPOM) than for CPOM by factors of 1.5-7.
AN: 3627897
520 of 1521
TI: Vibrios in the marine and estuarine environment
AU: Colwell,-R.R.
AF: Univ. Maryland Biotechnol. Inst., 3021 Hartwork Rd., Suite 550, College Park, MD 20740, USA
CO: 3. International Marine Biotechnology Conference, Tromsoe, Norway, 7-12 Aug 1994
SO: 3RD-INTERNATIONAL-MARINE-BIOTECHNOLOGY-CONFERENCE:-PROGRAM,-ABSTRACTS-AND-LIST-OF-PARTICIPANTS. International-Advisory-Comm.-of-the-Int.-Marine-Biotechnology-Conference-1994,-Tromsoe-Norway TROMSOE-NORWAY TROMSOE-UNIVERSITY 1994 p. 92
LA: English
ER: M (Marine)
AB: Microbial populations of the estuarine, coastal, and marine environment have been under study for ca. 100 years, tracing to oceanographic voyages set to map and chart the physical, chemical, and biological parameters of the world oceans. Very early in marine microbiology it was discovered that many of those organisms which could be readily isolated from seawater and sediment were members of the Vibrionacae. In earlier classifications. Vibrionacae included both Vibrio and Aeromonas. Recent work on rRNA sequencing and DNA/DNA hybridization has shown that the Vibrionacae is separate and distinct taxonomically from the Aeromonadacae. Vibrios are readily cultivatable from seawater, marine animals, and seaweeds, leading to the hypothesis that vibrios comprise a dominant component of the microbial community structure of the marine environment. However, more recent work using direct detection of nucleic acid sequences (to determine the presence of organisms not yet cultivatable) demonstrated that there may be other species numerically in greater abundance. Nevertheless, the genus Vibrio includes organisms which are widely distributed in the marine environment. Some species are pathogenic for fish and shellfish, as well as for humans (e.g. Vibrio cholerae, Vibrio vulnificus, Vibrio parahaemolyticus, etc.). The role of vibrios in the marine environment has been shown to include biodegradation, nutrient regeneration, and biogeochemical cycling. Many species of vibrios are luminescent and a number are also capable of fixing nitrogen. Vibrios are associated with plankton, notably zooplankton. Recently, it has been possible to monitor species by fluorescent tagging of gene and antibody probes. Thus, global dispersion and distribution of microorganisms and seasonality shifts can now be monitored. Seasonality of Vibrio species, both in temperate and semi-tropical environments has been demonstrated. Autoecological principles, at the microbial level, and microbial diversity can be better appreciated by mapping species, such as Vibrio, in estuaries and the ocean.
AN: 3627802
521 of 1521
TI: Deep bacterial biosphere in Pacific Ocean sediments
AU: Parkes,-R.J.; Cragg,-B.A.; Bale,-S.J.; Getliff,-J.M.; Goodman,-K.; Rochelle,-P.A.; Fry,-J.C.; Weightman,-A.J.; Harvey,-S.M.
AF: Dep. Geol., Univ. Bristol, Bristol BS8 1RJ, UK
SO: NATURE 1994 vol. 37, no. 6496, pp. 410-413
LA: English
ER: M (Marine)
AB: Although around 70% of the Earth's surface is marine, little is known about the microbiology of underlying sediments, which can be more than a kilometre deep. Selective degradation of organic matter within sediments over geological time profoundly affects the chemical composition of the ocean and atmosphere. Microbial processes have a fundamental role in surface sediments, but despite geochemical evidence, their significance in deeper sediments has not been established. Here we report the discovery of viable sediment bacterial populations at five Pacific Ocean sites to depths > 500 m. Bacterial distributions and activities are commensurate with geochemical changes. Bacterial profiles with depth are remarkably consistent, and deviations can be linked to specific environmental factors. The rate of decline in these populations indicates that bacteria are present to even greater depths. These bacteria, some of which are unique, must have a profound effect on deep-sediment diagenetic processes, and their presence considerably extends the biosphere.
AN: 3627411
522 of 1521
TI: Carbon dioxide supersaturation in the surface waters of lakes
AU: Cole,-J.J.; Caraco,-N.F.; Kling,-G.W.; Kratz,-T.K.
AF: Inst. Ecosystem Stud., Cary Arboretum, Millbrook, NY 12545, USA
SO: SCIENCE-WASH. 1994 vol. 265, no. 5178, pp. 1568-1570
LA: English
ER: F (Freshwater)
AB: Data on the partial pressure of carbon dioxide (CO sub(2)) in the surface waters from a large number of lakes (1835) with a worldwide distribution show that only a small proportion of the 4665 samples analyzed (less than 10 percent) were within plus or minus 20 percent of equilibrium with the atmosphere and that most samples (87 percent) were supersaturated. The mean partial pressure of CO sub(2) averaged 1036 microatmospheres, about three times the value in the overlying atmosphere, indicating that lakes are sources rather than sinks of atmospheric CO sub(2). On a global scale, the potential efflux of CO sub(2) from lakes (about 0.14 x 10 super(15) grams of carbon per year) is about half as large as riverine transport of organic plus inorganic carbon to the ocean. Lakes are a small but potentially important conduit for carbon from terrestrial sources to the atmospheric sink.
AN: 3627404
523 of 1521
TI: Carbon dynamics in a forested peatland in north-eastern Ontario, Canada
AU: Charman,-D.J.; Aravena,-R.; Warner,-B.G.
AF: Dep. Geogr. Sci., Univ. Plymouth, Plymouth, Devon PL4 8AA, UK
SO: J.-ECOL. 1994 vol. 82, no. 1, pp. 55-62
LA: English
ER: F (Freshwater)
AB: The long-term carbon accumulation rate in a forested peatland in north-east Ontario was examined in relation to gas production and factors which control carbon transport. Plots of cumulative total mass and cumulative carbon mass against calibrated radiocarbon age estimates when applied to an existing model of peat accumulation, suggest that only very slow decay is occurring within the catotelm. Gas samples collected from depth show that both carbon dioxide and methane are present. Accelerator mass spectrometry (AMS) radiocarbon analysis yields age estimates of both gases which are between 500 and 2000 years younger than conventional age estimates on adjacent peat. It is suggested that this is due to the downward transport of younger carbon, probably as part of the dissolved organic carbon (DOC) in pore waters. High tritium content of peat pore water at depth indicates the presence of water recharged during the last 40 years and therefore supports this hypothesis. Hydrological data from piezometers confirms the existence of hydraulic gradients for vertical water movement and shows that the direction of flow varies seasonally. The results indicate that the internal carbon dynamics of peatlands are more complex than has previously been thought and that hydrology may be an important factor in the supply of source carbon for anaerobic decay.
AN: 3627400
524 of 1521
TI: On the balance of hydrocarbon compounds in Lake Baikal.
OT: O balanse uglevodorodnykh soedinenij v ozere Bajkal
AU: Snytko,-V.A.; Afonina,-T.E.
SO: IZV.-RGO 1994 vol. 126, no. 3, pp. 65-69
LA: Russian
ER: F (Freshwater)
AB: The paper presents data on the production-destruction of autochthonous hydrocarbons and on the input and transformation of allochthonous (terrigenous) and technogenous hydrocarbons in different areas of the lake. Tabulated data on the balance of hydrocarbons in the lake are provided.
AN: 3626993
525 of 1521
TI: Physical and biological controls on carbon cycling in the Equatorial Pacific
AU: Murray,-J.W.; Barber,-R.T.; Roman,-M.R.; Bacon,-M.P.; Feely,-R.A.
AF: Sch. Oceanogr., Univ. Washington, Seattle, WA 98195, USA
SO: SCIENCE-WASH. 1994 vol. 266, no. 5182, pp. 58-65
LA: English
AB: The Equatorial Pacific is the largest oceanic source of carbon dioxide to the atmosphere and has been proposed to be a major site of organic carbon export to the deep sea. Study of the chemistry and biology of this area from 170 degree to 95 degree W suggests that variability of remote winds in the western Pacific and tropical instability waves are the major factors controlling chemical and biological variability. The reason is that most of the biological production is based on recycled nutrients; only a few of the nutrients transported to the surface by upwelling are taken up by photosynthesis. Biological cycling within the euphotic zone is efficient, and the export of carbon fixed by photosynthesis is small. The fluxes of carbon dioxide to the atmosphere and particulate organic carbon to the deep sea were about 0.3 gigatons per year, and the production of dissolved organic carbon was about three times as large. The data establish El Nino events as the main source of interannual variability.
AN: 3622879
526 of 1521
TI: Retention of sulfur in lake sediments
AU: Urban,-N.R.
AF: Lake Res. Lab., Swiss Fed. Inst. for Water Resour. and Water Pollut. Control (EAWAG/ETH), CH-6047 Kastanienbaum, Switzerland
CO: 201. Natl. Meet. of the American Chemical Society, Atlanta, GA (USA), 14-19 Apr 1991
SO: ENVIRONMENTAL-CHEMISTRY-OF-LAKES-AND-RESERVOIRS. Baker,-L.A.-ed. WASHINGTON,-DC-USA AMERICAN-CHEMICAL-SOCIETY 1994 vol. 237 pp. 323-369
ST: ADV.-CHEM.-SER. vol. 237
LA: English
ER: F (Freshwater)
AB: Measurements of S cycling in Little Rock Lake, Wisconsin, and Lake Sempach, Switzerland, are used together with literature data to show the major factors regulating S retention and speciation in sediments. Retention of S in sediments is controlled by rates of seston (planktonic S) deposition, sulfate diffusion, and S recycling. Data from 80 lakes suggest that seston deposition is the major source of sedimentary S for approximately 50% of the lakes; sulfate diffusion and subsequent reduction dominate in the remainder. Concentrations of sulfate in lake water and carbon deposition rates are important controls on diffusive fluxes. Diffusive fluxes are much lower than rates of sulfate reduction, however. Rates of sulfate reduction in many lakes appear to be limited by rates of sulfide oxidation. Much sulfide oxidation occurs anaerobically, but the pathways and electron acceptors remain unknown. The intrasediment cycle of sulfate reduction and sulfide oxidation is rapid relative to rates of S accumulation in sediments. Concentrations and speciation of sulfur in sediments are shown to be sensitive indicators of paleolimnological conditions of salinity, aeration, and eutrophication.
AN: 3619718
527 of 1521
TI: Mass fluxes and recycling of phosphorus in Lake Michigan. Role of major particle phases in regulating the annual cycle
AU: Shafer,-M.M.; Armstrong,-D.E.
AF: Water Chem. Program, Water Sci. and Eng. Lab., Univ. Wisconsin, Madison, WI 53706, USA
CO: 201. Natl. Meet. of the American Chemical Society, Atlanta, GA (USA), 14-19 Apr 1991
SO: ENVIRONMENTAL-CHEMISTRY-OF-LAKES-AND-RESERVOIRS. Baker,-L.A.-ed. WASHINGTON,-DC-USA AMERICAN-CHEMICAL-SOCIETY 1994 vol. 237 pp. 285-322
ST: ADV.-CHEM.-SER. vol. 237
LA: English
ER: F (Freshwater)
AB: Biogeochemical cycling of phosphorus in a water column in southern Lake Michigan was examined, and the significance of major particle phases to the annual mass flux and recycling of phosphorus was assessed. Comparison of 1982-1983 total P and total filtrable P concentrations with data from 1990-1991 and other published data showed little change. The measured annual primary flux of P to the sediment surface reflected rapid sedimentation of both allochthonous particles and spring diatom production. Diatoms were the dominant vector of P to the sediment surface. Terrigenous phases and autochthonous calcite were also significant. More than half of the mixed-period diatom P demand was provided by colloidal and particulate P, nearly 60% of diatom-associated P was recycled within the water column, and 55-58% of total primary P flux was recycled at the sediment surface. Ultimately 2.2% of C and 2.7% of P became incorporated into recent sediments. The amount of P supplied by resuspension was relatively small compared with water-column standing pools and major flux vectors. With its relatively long residence, the response time for P changes with respect to loading should be on the order of 5-15 years.
AN: 3619714
528 of 1521
TI: Ecosystem-scale experiments. The use of stable isotopes in fresh waters
AU: Kling,-G.W.
AF: Dep. Biol., Univ. Michigan, Ann Arbor, MI 48109-1048, USA
CO: 201. Natl. Meet. of the American Chemical Society, Atlanta, GA (USA), 14-19 Apr 1991
SO: ENVIRONMENTAL-CHEMISTRY-OF-LAKES-AND-RESERVOIRS. Baker,-L.A.-ed. WASHINGTON,-DC-USA AMERICAN-CHEMICAL-SOCIETY 1994 vol. 237 pp. 91-120
ST: ADV.-CHEM.-SER. vol. 237
LA: English
ER: F (Freshwater)
AB: Experimental studies using additions of stable isotopes of nitrogen and carbon to an arctic lake indicated that new primary production rather than terrestrial detritus supports most animals in the planktonic food web and to a lesser degree in the benthic food web. The lake was divided by a curtain, and one half was fertilized with N and P through a 6-week experiment. super(15)NH sub(4)Cl was added to both sides to label algae; terrestrial detritus remained unlabeled. Although nutrients cycled more quickly in the fertilized treatment, the trophic pathways of nitrogen flow were unaltered by fertilization. The retention time of nitrogen in the ecosystem was about 3 years in both control and fertilized treatments. super(13)C-leucine additions to mesocosms indicated that phytoplankton make direct use of amino acids and that some macrozooplankton derive nutrition from the microbial food web.
AN: 3619689
529 of 1521
TI: Environmental chemistry of lakes and reservoirs
AU: Baker,-L.A.-(ed.)
CO: 201. Natl. Meet. of the American Chemical Society, Atlanta, GA (USA), 14-19 Apr 1991
SO: ADV.-CHEM.-SER. WASHINGTON,-DC-USA AMERICAN-CHEMICAL-SOCIETY 1994 vol. 237, 627 pp
LA: English
ER: F (Freshwater)
AB: This book explores a broad range of research dealing with the environmental chemistry of lakes and reservoirs. Both it and the symposium on which it is based were developed with four goals in mind. The first was to include a wide spectrum of topics, ranging from trace metal cycling and nutrient biogeochemistry to organic geochemistry. Second, there was an emphasis on timeliness, with an effort to include only work that was coming into full fruition, neither preliminary nor overwrought. Third, the book was to have a distinctly practical orientation reflecting the background of the editor, an environmental engineer. Finally, this volume was intended to reach a broad audience, including not only chemists, but also environmental engineers and biologists; scientists involved in practical aspects of water pollution, as well as those with a theoretical bent. The chapters are divided into four groups. The first section emphasizes methodological advances in studies of lake geochemistry. The second section examines the cycling and distribution of major elements (C, N, S, O, and P) in aquatic systems. The third section focuses on the behavior of trace metals, with an emphasis on processes that control their solubility and transport. The last section deals with several organic contaminants.
AN: 3619671
530 of 1521
TI: Enhanced calcification in the coccolithophorid Emiliania huxleyi (Haptophyceae) under phosphorus limitation
AU: Paasche,-E.; Brubak,-S.
AF: Sect. Mar. Bot., Dep. Biol., Univ. Oslo, P.O. Box 1069, Blindern, 0316 Oslo, Norway
SO: PHYCOLOGIA 1994 vol. 33, no. 5, pp. 324-330
LA: English
ER: M (Marine)
AB: The effect of phosphorus limitation on calcification in the coccolithophorid Emiliania huxleyi (Lohmann) Hay et Mohler was investigated by chemical Ca and C analyses, as well as in short-term super(14)C uptake experiments. The latter made use of a newly developed microdiffusion method to separate super(14)C in coccolith carbonate from photosynthetically assimilated super(14)C. In comparison with exponentially growing cells in a nutrient-replete medium, cells grown in P-limited chemostats at half the maximum growth rate produced c. 60% more CaCO sub(3) relative to organic carbon. In the short-term incubations, cells from P-limited chemostats showed a relative increase in the capacity for calcification under reduced irradiance and in the dark, Nutrient effects on calcification are of potential interest in considerations of the impact of E. huxleyi blooms on the sea-air CO sub(2) interchange, and they deserve further study.
AN: 3616744
531 of 1521
TI: Minimal effect of iron fertilization on sea-surface carbon dioxide concentrations
AU: Watson,-A.J.; Law,-C.S.; Van-Scoy,-K.A.; Millero,-F.J.; Yao,-W.; Friedderich,-G.E.; Liddicoat,-M.I.; Wanninkhof,-R.H.; Barber,-R.T.; Coale,-K.H.
AF: Plymouth Mar. Lab., Prospect Place, West Hoe, Plymouth PL1 3DH, UK
SO: NATURE 1994 vol. 371, no. 6493, pp. 143-145
LA: English
ER: M (Marine)
AB: It has long been hypothesized that iron concentrations limit phytoplankton productivity in some parts of the ocean. As a result, iron may have played a role in modulating atmospheric CO sub(2) levels between glacial and interglacial times, and it has been proposed that large-scale deposition of iron in the ocean might be an effective way to combat the rise of anthropogenic CO sub(2) in the atmosphere. As part of an experiment in the equatorial Pacific Ocean, we observed the effect on dissolved CO sub(2) of enriching a small (8 x 8 km) patch of water with iron. We saw significant depression of surface fugacities of CO sub(2) within 48 hours of the iron release, which did not change systematically after that time. But the effect was only a small fraction ( similar to 10%) of the CO sub(2) drawdown that would have occurred had the enrichment resulted in the complete utilization of all the available nitrate and phosphate. Thus artificial fertilization of this ocean region did not cause a very large change in the surface CO sub(2) concentration, in contrast to the effect observed in incubation experiments, where addition of similar concentrations of iron usually results in complete depletion of nutrients. Although our experiment does not necessarily mimic all circumstances under which iron deposition might occur naturally, our results do not support the idea that iron fertilization would significantly affect atmospheric CO sub(2) concentrations.
AN: 3616672
532 of 1521
TI: River mouths and lagoons as a buffer zone for matter transport from land to the Black Sea.
OT: Ust'ya rek i limany kak bufernaya zona dlya potoka veshchestv s sushi v Chernoe more
AU: Shil'-krot,-G.S.
AF: Inst. Geogr. RAN, Moscow, Russia
SO: IZV.-RAN-GEOGR.-PROC.-RUSS.-ACAD.-SCI.-GEOGR. 1994 no. 2, pp. 100-111
LA: Russian
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The paper is a review of original and literature data on the fate of chemical pollutants (heavy metals, pesticides) in the ecosystems of water bodies of the northwestern Black Sea coast including river mouths and lagoons of various types. Data on the content of trace elements in water, macrophytes and bottom sediments in the estuaries of the Danube and Dnieper R. and in some coastal lagoons are provided in tabular form.
AN: 3616623
533 of 1521
TI: The uptake of iodate by marine phytoplankton
AU: Moisan,-T.A.; Dunstan,-W.M.; Udomkit,-A.; Wong,-G.T.F.
AF: Scripps Inst. Oceanogr., Univ. California, San Diego, CA 92093-0218, USA
SO: J.-PHYCOL. 1994 vol. 30, no. 4, pp. 580-587
LA: English
ER: M (Marine)
AB: Several studies have suggested that phytoplankton play a role in the iodine cycle. Using a short-term incubation technique for determining the uptake of iodate by phytoplankton, cultures of Thalassiosira oceanica Hasle, Skeletonema costatum (Greville) Cleve, Emiliania huxleyi (Lohmann) Hay and Mohler, and Dunaliella tertiolecta Butcher were found to be capable of assimilating iodate at rates ranging from 0.003 to 0.24 nmol IO sub(3) super(-)/ mu g chlorophyll a/h. The kinetics for the uptake of iodate can be modeled, and the similarity between the model and experimental results suggests that there is a steady state between iodate uptake and release of dissolved iodine from the cells, presumably in the form of iodide. Two experiments were conducted in the Sand Shoal Inlet of the Cobb Bay estuary (37 degree 15' N, 75 degree 50'W). The uptake of iodate was 0.26 and 0.08 nmol IO sub(3) super(-)/ mu g chlorophyll a/h during high and low tide, respectively. Using field estimates based on measured levels of iodate in the estuary, we estimate that phytoplankton can take up as much as 3% of the ambient pool of iodate on a daily basis and the entire pool in about 1 month. Thus, phytoplankton can be a significant component of the global iodine cycle by mediating changes in the speciation of iodine in the marine environment.
AN: 3615857
534 of 1521
TI: Calcification rates of rapidly colonising bryozoans in Hauraki Gulf, northern New Zealand
AU: Smith,-A.M.; Nelson,-C.S.
AF: Dep. Mar. Sci., Univ. Otago, P.O. Box 56, Dunedin, New Zealand
SO: N.Z.-J.-MAR.-FRESHWAT.-RES. 1994 vol. 28, no. 2, pp. 227-234
LA: English
ER: M (Marine)
AB: Very little is known about calcification rates of bryozoans, despite their importance in modern temperate-latitude shelf carbonate sediments and in temperate limestones. Here we report the carbonate production rates for 19 species of bryozoans over 3, 9, and 12-month periods from a settling experiment in 14 m water depth at Cape Rodney, Hauraki Gulf. Based on the larger bryozoan colonies, estimates of calcification rate range from 25 to 740 mg CaCO sub(3)/y. Extrapolation of calcification rate to overall bryozoan sediment production is not straightforward, but a value of 24-240 g CaCO sub(3)/m/y for the sample site has been determined, equivalent to a sediment accumulation rate of 4-40 cm per 1000 years (ky). In reality, over a large shelf region both dilution by other organisms and a patchy areal distribution of living bryozoans would reduce these values to only a few cm k/y. The relatively low rates of accumulation deduced here are mainly consistent with the few other studies of bryozoan sedimentation in temperate waters, and also with those typically reported (1-3 cm k/y) for many occurrences of temperate bryozoan-rich limestones from the rock record.
AN: 3614738
535 of 1521
TI: Preservation of primary productivity signal in Antarctic fjord sediments: Andvord Bay, Antarctica
AU: Domack,-E.W.; Mashiotta,-T.A.; Venkatsen,-M.I.
AF: Geol. Dep., Hamilton Coll., Clinton, NY 13323, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 66-67
LA: English
ER: M (Marine)
AB: This study is an interdisciplinary investigation into the paleoproductivity of an antarctic fjord based on sedimentologic and biogeochemical studies of a 9-meter-long piston core. We collected core 22 from Andvord Bay (64 degree 49.625' S 62 degree 39.001' W) in early 1988 as part of R/V Polar Duke cruise III. The chronology of core 22 extends back for approximately the last 3,000 years as based upon a set of five radiocarbon ages that range in age from 2025 plus or minus 60 to 4480 plus or minus 75 (table 1). These data result in a linear accumulation rate of 0.305 centimeters per year and interval rates of 0.23 and 0.52 centimeters per year for the upper and lower portions of the core respectively.
AN: 3613140
536 of 1521
TI: Distribution and production of biogenic silica in the upper water column of the Ross Sea 1990-1992
AU: Nelson,-D.M.; Gordon,-L.I.
AF: Coll. Oceanogr., Oregon State Univ., Corvallis, OR 97330, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 72-74
LA: English
ER: M (Marine)
AB: During February and early March of 1992 we made the second cruise of an ongoing study of the cycling of biogenic silica in the Ross Sea. This work is part of a coordinated interdisciplinary effort to understand the biogeochemical cycling of organic and siliceous matter in the Antarctic, being conducted in collaboration with W.O. Smith, University of Tennessee (primary productivity and organic-matter cycling) R. B. Dunbar, Rice University (vertical fluxes of organic and siliceous material through the water column) and D.J. DeMaster, North Carolina State University (sediment accumulation and early digenesis of silica and carbon). In 1990 and 1992 sampling was performed from the R/V Polar Duke. In both years we collected data over the entire Ross Sea shelf, emphasizing transect about 600 kilometers in length extending eastward from the shore-fast ice near the Victoria Land coast.
AN: 3613137
537 of 1521
TI: The accumulation and regeneration of biogenic silica and organic carbon in Ross Sea sediments
AU: DeMaster,-D.J.; Pope,-R.H.; Smoak,-J.M.; Nittrouer,-C.A.; Pierson,-G.H.
AF: Dep. Mar., Earth, and Atmos. Sci., North Carolina State Univ., Raleigh, NC 27695, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 74-76
LA: English
ER: M (Marine)
AB: Accumulation rates and regeneration rates for biogenic silica and organic carbon are being measured in Ross Sea sediments. As part of a larger project examining biogeochemical fluxes in the waters and sediments of the Ross Sea, this research provide information that allows a comparison of surface biogenic production rates with biogenic accumulation rates in the seabed below. This study evaluates lateral transport of material based on data from current meters and transmissometers moored at three Ross Sea locations for a period of two years. In formal of this type is essential for an understanding of the oceanographic processes that control the recycling and accumulation of biogenic material in high-latitude environments. During February 1992 we conducted the concluding field program for the Ross Sea Project. Using the USCGC Polar Sea and the R/V Polar Duke, we successfully recovered our three moorings and occupied 146 stations. We collected sediment with a kasten corer and/or a spade box corer at 36 stations.
AN: 3613136
538 of 1521
TI: The movement of suspended materials in the Ross Sea
AU: Nittrouer,-C.A.; Pierson,-G.H.; Morrison,-J.M.; DeMaster,-D.J.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 77-79
LA: English
ER: M (Marine)
AB: Lateral fluxes of suspended materials are being investigated as part of a larger study to understand biogeochemical fluxes in the Ross Sea. The primary objective is to provide insight that can be used to evaluate models describing the fate of biogenic Si and carbon. In particular, the limitations on one-dimensional, vertical models are being examined in light of observed horizontal advection. Much of the suspended material in the Ross Sea is lithogenic sediment, and therefore a better understanding of general glacial-marine sedimentation is also being obtained.
AN: 3613135
539 of 1521
TI: Influence of terrestrial weathering on early diagenetic reactions in continental shelf sediments
AU: Aller,-R.C.
AF: Mar. Sci. Res. Cent., SUNY at Stony Brook, Stony Brook, NY 11794-5000, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 437-438
LA: English
ER: M (Marine)
AB: Much of the recent emphasis in studies of early diagenetic reactions is on the cycling of biogenic debris. Lithogenic particles, their properties and the processes that formed them are often given little consideration other than as a diluent. With the discovery of extensive hydrothermal systems, interest has also waned in the possible relationships of terrestrial weathering and potential reverse weathering processes during early diagenesis of marine sediments. Studies of Amazon Shelf deposits demonstrate that this lack of interest is unwarranted and that terrestrial weathering processes can apparently have major influences not only on authigenic silicate formation but on biogeochemical reaction balances and minor element export processes in continental shelf deposits.
AN: 3613134
540 of 1521
TI: Cobalt(II) oxidation by the marine manganese(II)-oxidizing Bacillus sp. strain SG-1
AU: Lee,-Yoon; Tebo,-B.M.*
AF: Mar. Biol. Res. Div., Scripps Inst. Oceanogr., Univ. California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0202, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1994 vol. 60, no. 8, pp. 2949-2957
LA: English
ER: M (Marine)
AB: The geochemical cycling of cobalt (Co) has often been considered to be controlled by the scavenging and oxidation of Co(II) on the surface of manganese [Mn(III,IV)] oxides or manganates. Because Mn(II) oxidation in the environment is often catalyzed by bacteria, we have investigated the ability of Mn(II)-oxidizing bacteria to bind and oxidize Co(II) in the absence of Mn(II) to determine whether some Mn(II)-oxidizing bacteria also oxidize Co(II) independently of Mn oxidation. We used the marine Bacillus sp. strain SG-1, which produces mature spores that oxidize Mn(II), apparently due to a protein in their spore coats. A method to measure Co(II) oxidation using radioactive super(57)Co as a tracer and treatments with nonradioactive (cold) Co(II) and ascorbate to discriminate bound Co from oxidized Co was developed. SG-1 spores were found to oxidize Co(II) over a wide range of pH, temperature, and Co(II) concentration. Leucoberbelin blue, a reagent that reacts with Mn(III,IV) oxides forming a blue color, was found to also react with Co(III) oxides and was used to verify the presence of oxidized Co in the absence of added Mn(II). Co(II) oxidation occurred optimally around pH 8 and between 55 and 65 degree C. SG-1 spores oxidized Co(II) at all Co(II) concentrations tested from the trace levels found in seawater to 100 mM. Co(II) oxidation was found to follow Michaelis-Menten kinetics. An Eadie-Hofstee plot of the data suggests that SG-1 spores have two oxidation systems, a high-affinity-low-rate system and a low-affinity-high-rate system. SG-1 spores did not oxidize Co(II) in the absence of oxygen, also indicating that oxidation was not due to abiological Co(II) oxidation on the surface of preformed Mn(III,IV) oxides. These results suggest that some microorganisms may directly oxidize Co(II) and such biological activities may exert some control on the behavior of Co in nature. SG-1 spores may also have useful applications in metal removal, recovery, and immobilization processes.
AN: 3613099
541 of 1521
TI: Total epiphyte and epiphytic carbonate production on Thalassia testudinum across Florida Bay
AU: Frankovich,-T.A.; Zieman,-J.C.
AF: Southeast Environ. Res. Program, OE 148, Florida Int. Univ., Miami, FL 33199, USA
CO: 1992 Symp. on Florida Keys Regional Ecosystem, Miami, FL (USA), Nov 1992
SO: SYMPOSIUM-ON-FLORIDA-KEYS-REGIONAL-ECOSYSTEM.-NOVEMBER-1992. Prospero,-J.M.;Harwell,-C.C.-eds. 1994 vol. 54, no. 3 pp. 679-695
ST: BULL.-MAR.-SCI. vol. 54, no. 3
LA: English
ER: M (Marine)
AB: Previous investigations of epiphytic carbonate production have suggested that seagrass epiphytes are significant producers of calcium carbonate and may be a primary source of lime muds in Florida Bay. This study determined total epiphyte and epiphytic carbonate standing stocks and calculated minimum estimates of yearly production at seven sites within Florida Bay and one site oceanside of the northern Florida Keys. These sites span a larger geographical area of increased environmental variability than those of previous Florida Bay epiphyte studies which were conducted in areas where conditions are considered favorable for epiphyte production. Total epiphyte and epiphytic carbonate loads along with seagrass shoot density and productivity were measured during four periods between August 1991 and August 1992. Epiphyte composition, standing stock, and production all exhibited marked variation across Florida Bay. Calcifying epiphytes were dominant in Florida Bay, and their distribution and the distribution of epiphyte production appear to reflect differences in the physical characteristics of salinity and the variability thereof. Minimum estimates of annual epiphytic carbonate production range from 1.9 g CaCO sub(3)/m super(2)/yr to 282.7 g CaCO sub(3)/m super(2)/yr, a range lower than previous estimates. The differences between these estimates and previous ones are attributed to differences in environments and, to a lesser extent, differences in methodology.
AN: 3611547
542 of 1521
TI: Virus and bacteria abundances in the Drake Passage during January and August 1991
AU: Smith,-D.C.; Steward,-G.F.; Azam,-F.; Hollibaugh,-J.T.
AF: Scripps Inst. Oceanogr., Univ. California, San Diego, La Jolla, CA 92093-0202, USA
SO: ANTARCT.-J.-U.S. 1992 vol. 27, no. 5, pp. 125-127
LA: English
ER: M (Marine)
AB: High abundances of viruses have recently been discovered in various oceanic regimes and this has led to the suggestion that viruses may have a profound effect on food-web dynamics. If so, then current views on biogeochemical cycles in the ocean will need to be modified. Whether viruses are present in the southern ocean and, if so, whether they are as abundant as in other areas has not previously been addressed. We used transmission electron microscopy (TEM) to examine water samples from transects in both the winter and the summer in order to determine the spatial and temporal distribution of viruses in the southern ocean and its relationship to the distribution of bacteria.
AN: 3611251
543 of 1521
TI: Dissolved humic substances of vascular plant origin in a coastal marine environment
AU: Moran,-M.A.; Hodson,-R.E.
AF: Dep. Mar. Sci., Univ. Georgia, Athens, GA 30602-2206, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 4, pp. 762-771
LA: English
ER: M (Marine)
AB: Bacterial decomposition of vascular plant detritus in coastal wetlands results in the conversion of particulate organic matter to dissolved form and causes the release of humic substances into the bulk dissolved organic carbon (DOC) pool. We found that 34% of the DOC accumulating during degradation of salt marsh grass (Spartina alterniflora) form coastal wetlands of the southeastern U.S. fits the definition of humic substances and that lignin is the primary source of the dissolved humic substances (66% of the total). Although marine bacterioplankton used the lignin-rich humic substances more slowly and less efficiently than other components of the DOC pool, a significant fraction (24%) of these substances was mineralized within 7 weeks. Concentrations of vascular plant biomarkers (lignin phenols) indicate that 11-75% of the dissolved humic substances on southeastern U.S. continental shelf is from vascular plant-dominated environments. Calculations indicate that about half this material is contributed by the coastal salt marshes and half by river export. Vascular plant influence was lower in the bulk DOC pool (2-38%), indicating that terrestrially derived material is harbored preferentially in the humic substances subcomponent of marine DOC.
AN: 3608498
544 of 1521
TI: Sulfate reduction and diffusion in sediments of Little Rock Lake, Wisconsin
AU: Urban,-N.R.; Brezonik,-P.L.; Baker,-L.A.; Sherman,-L.A.
AF: Lake Res. Lab., EAWAG, Kastanienbaum, CH-6047, Switzerland
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 4, pp. 797-815
LA: English
ER: F (Freshwater)
AB: Rates of sulfate diffusion and reduction were measured in sediments of Little Rock Lake, an oligotrophic, soft-water lake in northern Wisconsin. Laboratory measurements of kinetics of sulfate reduction found half-saturation constants (20-30 mu mol/liter) and Q sub(10) values (2.6) similar to values reported in the literature. Sulfate reduction under in situ conditions in sediment cores was limited by sulfate and followed similar uptake kinetics as in laboratory experiments. Some variation in kinetic parameters was evident as a function of location in the lake. No seasonal variation was observed in sulfate reduction rates in the lake sediments, and littoral and pelagic sites exhibited similar rates. Rates of sulfate reduction were much higher than fluxes of sulfate calculated from pore-water profiles. Pore-water profiles also indicated little difference in diffusive fluxes among pelagic and littoral sites and among seasons. The discrepancy between diffusive fluxes and sulfate reduction rates is ascribed to high rates of oxidation of reduced sulfur. Nonlinear rates of sulfate reduction and calculated turnover times sediment sulfide pools support the hypothesis that sulfide oxidation occurs nearly as rapidly as sulfate reduction.
AN: 3608491
545 of 1521
TI: Probabilistic uncertainty assessment of phosphorus balance calculations in a watershed
AU: Taskinen,-A.; Varis,-O.; Sirvioe,-H.; Mutanen,-J.; Vakkilainen,-P.
AF: Helsinki Univ. Technol., Lab. Hydrol. Water Resour. Manage., FIN-02150 Espoo, Finland
CO: 2. International Conference on Reservoir Limnology and Water Quality Management, Ceske Budejovice (Czech Rep.), 9-14 Aug 1992
SO: ECOL.-MODEL. 1994 vol. 74, no. 1-2, pp. 125-135
LA: English
ER: F (Freshwater)
AB: Water quality studies in reservoirs, rivers, lakes, and entire river basins include increasingly often mass balance calculations. In comparison with hydrological studies where water balance models are traditionally frequently used, water quality investigations are typically faced with essentially higher uncertainty. This study presents an approach to the assessment and propagation of this uncertainty, with a case study on a river reach with three point source polluters, substantial throughflow, and non-point components. A computational implementation using spreadsheets was used, which allows the use of probabilistic models in close contact with environmental data bases.
AN: 3608452
546 of 1521
TI: The biogeochemistry of hydrogen sulfide: Phytoplankton production in the surface ocean
AU: Brooks,-A.S.; Edgington,-D.N.
AF: Cent. Great Lakes Stud., Univ. Wisconsin, Milwaukee, WI 53201, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 4, pp. 941-948
LA: English
ER: M (Marine)
AB: Hydrogen sulfide can exist in oxic waters in the form of a dissolved gas, dissociated ions, dissolved metal sulfide complexes, and particulate metal sulfides. The sum of the dissolved species is termed total dissolved sulfide (TDS). In addition to the hydrolysis of carbonyl sulfide, it has been speculated that phytoplankton may produce TDS. We present results from preliminary culture studies which demonstrate that phytoplankton produce TDS and particulate acid-volatile sulfide (pAVS). The phylogenetic order of TDS + pAVS production (per unit cell volume) for the oceanic species examined is Synechococcus sp. > Emiliania huxleyi ) Pyramimonas obovata > Thalassiosira oceanica. Moreover, TDS and pAVS production increases when the concentrations of uncomplexed trace metals in culture media are also increased, suggesting metal detoxification via the formation of metal sulfide complexes.
AN: 3607914
547 of 1521
TI: Biogeochemical control of phosphorus cycling and primary production in Lake Michigan
AU: Walsh,-R.S.; Cutter,-G.A.; Dunstan,-W.M.; Radford-Knoery,-J.; Elder,-J.T.
AF: Dep. Oceanogr., Old Dominion Univ., Norfolk, VA 23529-0276, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 4, pp. 961-968
LA: English
ER: F (Freshwater)
AB: A 3-yr study in Lake Michigan has shown a 27 mmol P/m super(2) increase in the mass of total P (TP) in the water during spring when the lake is mixed from surface to sediment. This value is an order of magnitude greater than the annual P input from external sources. TP changed in concert with increases in chlorophyll a and organic N and decreases in nitrate and soluble Si. The concentration of soluble reactive PO sub(4) super(3) super(-) (SRP) remained relatively constant throughout the study. We hypothesize that the SRP concentration is maintained by a chemical equilibrium with calcium-phosphate species. The increased mass of TP arises from the sequestering of P by algae which displaces the chemical equilibrium and allows more P to be released to the water from the sediments. Solar irradiance and the duration of mixing determine the magnitude of the spring bloom and the demand for P that must be supplied through the flux of P from the sediments to the overlying water.
AN: 3607900
548 of 1521
TI: Phosphorus regeneration by Lake Michigan alewives in the mid-1970s
AU: Kraft,-C.E.
AF: Univ. Wisconsin Sea Grant Inst., Univ. Wisconsin, 2420 Nicolet Dr., Green Bay, WI 54311-7001, USA
SO: TRANS.-AM.-FISH.-SOC. 1993 vol. 122, no. 5, pp. 749-755
LA: English
ER: F (Freshwater)
AB: A bioenergetics model of fish growth was used to estimate phosphorus (P) cycling by the population of Lake Michigan alewives Alosa pseudoharengus in the mid-1970s. The mean annual standing stock of alewives during the mid-1970s contained 1,500 tonnes of phosphorus, representing a substantial pool of particulate phosphorus unavailable to algae. An estimated 12,000 tonnes of phosphorus were egested and excreted annually by the Lake Michigan alewife population. Over half of the alewife-regenerated phosphorus was produced by larvae and age-0 alewives, which inhabit the nearshore epilimnion during summer. Seasonal aggregations of alewives-the dominant component of the Lake Michigan fish community during the mid-1970s-could have served as an important medium of phosphorus regeneration in comparison with more traditionally reported vehicles such as zooplankton. Expressed volumetrically, alewives regenerated 0.22 mu g P/L/d during August, which is comparable to phosphorus regeneration rates previously estimated for Lake Michigan zooplankton. Use of a bioenergetics model provided a means to demonstrate that alewives played a substantial role in Lake Michigan phosphorus regeneration during the mid-1970s.
AN: 3606734
549 of 1521
TI: Chitin production by crustaceans in marine ecosystem.
OT: La production de chitine par les crustaces dans les ecosystemes marins
AU: Jeuniaux,-C.; Voss-Foucart,-M.-F.; Bussers,-J.-C.
AF: Lab. Morphol., Systematique et Ecol. Animales, Inst. Van Beneden, Quai Van Beneden, 22, B-4020 Liege, Belgium
CO: 1. European Crustacean Conference, Paris (France), 31 Aug-4 Sep 1992
SO: AQUAT.-LIVING-RESOUR. 1993 vol. 6, no. 4, pp. 331-341
LA: French
AB: Chitin is synthesized by numerous animal species, either unicellular organisms or metazoans, belonging mainly to zoological groups of the Coelomate Spiralia lineage. However, the produced chitin in marine ecosystems is principally by crustaceans. A comparative study of analytical data so far available allowed calculation of chitin biomass and chitin production values in some types of marine ecosystems, and thus estimation of the quantitative importance of chitin in the biogeochemical cycles of carbon and nitrogen. The main data so far available concerns mediterranean plankton in Calvi bay (Corsica), arctic and antarctic krill, lobster population on South African coasts, and infralittoral benthic communities growing on rocky substrates on Corsica coasts. In all these cases, chitin production was estimated roughly at 1g per year and per square meter of rocky substrate or sea surface. Taking into account these production values and the relative extent of the main marine ecosystems over the world, the total production of chitin due to marine crustaceans was estimated at about 2.3 billion metric tons per year.
AN: 3606433
550 of 1521
TI: Automated in situ observations of upper ocean biogeochemistry, bio-optics, and physics and their potential use for global studies
AU: Dickey,-T.D.; Granata,-T.C.; Taupier-Ietage,-I.
CA: University of Southern California, Los Angeles (USA)
SO: 1992 37 pp
LA: English
ER: M (Marine)
AB: The process controlling the flux of carbon in the upper ocean have dynamic ranges in space and time of at least nine orders of magnitude. These processes depend on a broad suite of inter-related biogeochemical, bio-optical, and physical variables. These variables should be sampled on scales matching the relevant phenomena. Traditional ship-based sampling, while critical for detailed and more comprehensive observations, can span only limited portions of these ranges because of logistical and financial constraints. Further, remote observations from satellite platforms enable broad horizontal coverage which is restricted to the upper few meters of the ocean. For these main reasons, automated subsurface measurement systems are important for the fulfillment of research goals related to the regional and global estimation and modeling of time varying biogeochemical fluxes. Within the past few years, new sensors and systems capable of autonomously measuring several of the critical variables have been developed. The platforms for deploying these systems now include moorings and drifters and it is likely that autonomous underwater vehicles (AUV's) will become available for use in the future. Each of these platforms satisfies particular sampling needs and can be used to complement both shipboard and satellite observations. In the present review, (1) sampling considerations will be summarized, (2) examples of data obtained from some of the existing automated in situ sampling systems will be highlighted, (3) future sensors and systems will be discussed, (4) data management issues for present and future automated systems will be considered, and (5) the status of near real-time data telemetry will be outlined. Finally, we wish to make it clear at the outset that the perspectives presented here are those of the authors and are not intended to represent those of the United States JGOFS program, the International JGOFS program, NOAA's C&GC program, or other global ocean programs.
AN: 3605132
551 of 1521
TI: Ocean time-series near Bermuda: Hydrostation S and the US JGOFS Bermuda Atlantic time-series study
AU: Michaels,-A.F.; Knap,-A.H.
SO: 1992 21 pp
LA: English
ER: M (Marine)
AB: Bermuda is the site of two ocean time-series programs. At Hydrostation S, the ongoing biweekly profiles of-temperature, salinity and oxygen now span 37 years. This is one of the longest open-ocean time-series data sets and provides a view of decadal scale variability in ocean processes. In 1988, the U.S. JGOFS Bermuda Atlantic Time-series Study began a wide range of measurements at a frequency of 14-18 cruises each year to understand temporal variability in ocean biogeochemistry. On each cruise, the data range from chemical analyses of discrete water samples to data from electronic packages of hydrographic and optics sensors. In addition, a range of biological and geochemical rate measurements are conducted that integrate over time-periods of minutes to days. This sampling strategy yields a reasonable resolution of the major seasonal patterns and of decadal scale variability. The Sargasso Sea also has a variety of episodic production events on scales of days to weeks and these are only poorly resolved. In addition, there is a substantial amount of mesoscale variability in this region and some of the perceived temporal patterns are caused by the intersection of the biweekly sampling with the natural spatial variability. In the Bermuda time-series programs, we have added a series of additional cruises to begin to assess these other sources of variation and their impacts on the interpretation of the main time-series record. However, the adequate resolution of higher frequency temporal patterns will probably require the introduction of new sampling strategies and some emerging technologies such as biogeochemical moorings and autonomous underwater vehicles.
AN: 3605040
552 of 1521
TI: JGOFS North Atlantic bloom experiment: An overview
AU: Ducklow,-H.W.
CA: Maryland Univ., Cambridge (USA). Horn Point Environmental Labs.
SO: 1992 23 pp
LA: English
ER: M (Marine)
AB: The North Atlantic Bloom Experiment (NABE) of JGOFS presents a unique opportunity and challenge to the data management community because of the diversity and large size of biogeochemical data sets collected. NABE was a pilot study for JGOFS and has also served as a pilot study within the U.S. NODC for management and archiving of the data sets. Here I present an overview to some of the scientific results of NABE, which will be published as an Introduction to a special volume of NABE results in Deep-Sea Research later this year. An overview of NABE data management is given elsewhere in the present report. This is the first collection of papers from the Joint Global Ocean Flux Study (JGOFS). Formed as an international program in 1987, JGOFS has four principal elements: modelling and data management, multidisciplinary regional process studies, a global survey of biogeochemical properties and long-term time series observatories. In 1989-1990 JGOFS conducted a pilot process study of the spring phytoplankton bloom the North Atlantic Bloom Experiment (NABE). JGOFS decided to conduct a large scale, internationally-coordinated pilot study in the North Atlantic because of its proximity to the founding nations of the project, the size and predictability of the bloom and its fundamental impact on ocean bio-geochemistry (Billett et al., 1983; Watson and Whitfield, 1985; Pfannkuche, 1992). In 1989, six research vessels from Canada, Germany. The Netherlands, the United Kingdom and the USA and over 200 scientists and students from more than a dozen nations participated in NABE. Some of their initial results are reported in this volume.
AN: 3605033
553 of 1521
TI: Data management for community research projects: A JGOFS case study
AU: Lowry,-R.K.
CA: Proudman Oceanographic Lab., Bidston (UK)
SO: 1992 23 pp
LA: English
ER: M (Marine)
AB: Since the mid 1980s, much of the marine science research effort in the United Kingdom has been focused into large scale collaborative projects involving public sector laboratories and university departments, termed Community Research Projects. Two of these, the Biogeochemical Ocean Flux Study (BOFS) and the North Sea Project incorporated large scale data collection to underpin multidisciplinary modeling efforts. The challenge of providing project data sets to support the science was met by a small team within the British Oceanographic Data Center (BODC) operating as a topical data center. The role of the data center was to both work up the data from the ship's sensors and to combine these data with sample measurements into online databases. The working up of the data was achieved by a unique symbiosis between data center staff and project scientists. The project management, programming and data processing skills of the data center were combined with the oceanographic experience of the project communities to develop a system which has produced quality controlled, calibrated data sets from 49 research cruises in 3.5 years of operation. The data center resources required to achieve this were modest and far outweighed by the time liberated in the scientific community by the removal of the data processing burden. Two online project databases have been assembled containing a very high proportion of the data collected. As these are under the control of BODC their long term availability as part of the UK national data archive is assured. The success of the topical data center model for UK Community Research Project data management has been founded upon the strong working relationships forged between the data center and project scientists. These can only be established by frequent personal contact and hence the relatively small size of the UK has been a critical factor. However, projects covering a larger, even international scale could be successfully supported by a network of topical data centers managing online databases which are interconnected by object oriented distributed data management systems over wide area networks.
AN: 3605014
554 of 1521
TI: Modelling chemico-biological cycles in the White Sea: Computation of seasonal carbon compounds variability.
OT: Modelirovanie khimiko-biologicheskikh tsiklov v Belom more: Reschet sezonnoj izmenchivosti soedinenij ugleroda
AU: Yakushev,-E.V.; Mikjajlovskij,-G.E.
AF: Inst. Okeanol., Moscow, Russia
SO: OKEANOLOGIYA 1994 vol. 34, no. 2, pp. 240-247
LA: Russian
ER: M (Marine)
AB: The paper describes a mathematical model developed to estimate the effect of marine biota on seasonal variations of carbon compounds. The model parametrizes chemico-biological processes, chemical transformation processes within the carbonate system, hydrophysical processes, water-air exchange and sedimentation. The model permitted computation of the range of seasonal variations in the carbonate system parameters and estimation of the separate contribution of hydrophysical (60%) and biological (40%) processes to this range. The effect of biota is mainly manifested as changes in pH during the spring bloom resulting in disturbance of the carbonate system balance, temporary increase of carbonate ion and decrease of free carbon dioxide content, which in turn causes anomalies in the seasonal variability of the intensity of carbon dioxide flux across the air-sea interface.
AN: 3604958
555 of 1521
TI: The release of phosphorus from oxygenated estuarine sediments
AU: Maher,-W.A.; DeVries,-M.
AF: Water Res. Cent., Univ. Canberra, P.O. Box 1, Belconnen, ACT 2616, Australia
SO: CHEM.-GEOL. 1994 vol. 112, no. 1-2, pp. 91-104
LA: English
ER: M (Marine)
AB: Grab samples were collected at the oxygenated sediment-water interface during August 1987 from eight stations along the longitudinal salinity gradient of the Beaulieu River Estuary, south-central England. The bulk sediment composition and phosphorus associations in the sediments were determined to identify the factors causing phosphorus concentrations and associations to vary in the sediments. Bulk sediment elemental composition and organic matter content were unrelated to sedimentary total P, although there was a correlation with percentage silt and clay. Sediment fractionation studies indicated that the majority of bound sedimentary P was associated with the Fe-Al-sesquioxide phases which were in turn closely related to extractable Fe and Mn. Experiments were performed to determine the effect of salinity, agitation, biological activity, addition of a carbon source and degree of water oxygenation on P exchange between the estuarine sediments and the overlying water column. Phosphorus adsorption was decreased in deoxygenated sediments, and those supplemented with a secondary carbon source or a mixture of biocides, indicating that both release from iron oxides in reducing conditions at low Eh and microbiological conditions can influence P exchange. P release, however, did not deplete a specific P-containing fraction, but led instead to a redistribution of P between various sedimentary phases after extended experimental incubation. Sedimentary oxygen demand produced by carbon sources must be considered for proper management of eutrophication problems.
AN: 3603318
556 of 1521
TI: Gulf of Mexico hydrocarbon seep communities. 11. Carbon isotopic fractionation during fatty acid biosynthesis of seep organisms and its implication for chemosynthetic processes
AU: Fang,-Jiasong; Abrajano,-T.A.; Comet,-P.A.; Brooks,-J.M.; Sassen,-R.; MacDonald,-I.R.
AF: Geochem. and Environ. Res. Group, Coll. Geosci., Texas A&M Univ., 833 Graham Rd., College Station, TX 77845, USA
SO: CHEM.-GEOL. 1993 vol. 109, no. 1-4, pp. 271-279
LA: English
ER: M (Marine)
AB: The individual fatty acids of mytilids and vestimentiferan (Escarpis sp.) from hydrocarbon seeps exhibit light delta super(13)C-values: from -56.9 to -49.0ppt for the mytilids and from -38.6 to -31.6ppt for the vestimentiferan. Unsaturated fatty acids have lighter delta super(13)C than saturated ones. The variations in delta super(13)C are up to 5.1-6.7ppt (mytilids) and 7.0ppt (vestimentiferan) within a single specimen. It is suggested that a kinetic isotopic effect in the biosynthesis of fatty acids and intermolecular isotope fractionation during fatty acid desaturation and elongation are responsible for the observed distribution pattern. Fatty acids are depleted in super(13)C relative to the gills of the mytilids, whereas fatty acids of the vestimentiferan are enriched relative to trophosomes. The difference in delta super(13)C of fatty acids between mytilids and vestimentiferan reflects the differences in substrates (methane vs. CO sub(2)), and the different chemosynthetic processes of the invertebrates.
AN: 3603313
557 of 1521
TI: Data management for JGOFS: Theory and design
AU: Flierl,-G.R.; Bishop,-J.K.B.; Glover,-D.M.; Paranjpe,-S.
CA: Massachusetts Inst. of Technology, Cambridge (USA)
SO: pp. 229-249,
LA: English
ER: M (Marine)
AB: The Joint Global Ocean Flux Study (JGOFS), currently being organized under the auspices of the Scientific Committee for Ocean Research (SCOR), is intended to be a decade long internationally coordinated program. The main goal of JGOFS is to determine and understand on a global scale the processes controlling the time-varying fluxes of carbon and associated biogenic elements in the ocean and to evaluate the related exchanges with the atmosphere, sea floor and continental boundaries. "A long-term goal of JGOFS will be to establish strategies for observing, on long time scales, changes in ocean biogeochemical cycles in relation to climate change". Participation from a large number of U.S. and foreign institutions is expected. JGOFS investigators have begun a set of time-series measurements and global surveys of a wide variety of biological, chemical and physical quantities, detailed process-oriented studies, satellite observations of ocean color and wind stress and modeling of the biogeochemical processes. These experiments will generate data in amounts unprecedented in the biological and chemical communities; rapid and effortless exchange of these data will be important to the success of JGOFS.
AN: 3601553
558 of 1521
TI: Relation between inorganic nitrogen and phosphorus in Jiulongjiang Estuary and western Xiamen Harbour
AU: Chen,-Shuitu
AF: Fujian Inst. Oceanol., Xiamen 361012, People's Rep. China
SO: MAR.-SCI.-BULL.-HAIYANG-TONGBAO 1993 vol. 12, no. 5, pp. 26-32
LA: Chinese
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Based on the survey data of inorganic nitrogen and some species of phosphorus and other parameters from Jiulongjiang Estuary and western Xiamen Harbour from March 1987 to December 1988, the changes of the ratio of nitrogen to phosphorus is discussed in relation to primary productivity in the survey region. Nitrate and ammonium in the region had an influence on the geochemistry of phosphorus. N/P ratio was high with mean 36 similar to 64 except in spring and part of the estuary. Phosphorus, not nitrogen, was the limiting factor to phytoplanktonic growth. Higher nitrate content in the bottom layer hindered the release of phosphorus from surface sediment.
AN: 3601489
559 of 1521
TI: Isotopic tracers of nitrogen from atmospheric deposition to coastal waters
AU: Fogel,-M.L.; Paerl,-H.W.
AF: Carnegie Inst. Washington, Geophys. Lab., Washington, DC, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 233-236
LA: English
ER: M (Marine)
AB: Nitrogen deposition to global oceans from the atmosphere can be about two times that of natural riverine input. Even accounting for the increased loading of riverine nitrogen by anthropogenic inputs, total atmospheric deposition (AD) is essentially equal to that of riverine sources. Among growth-limiting nutrients, nitrogen plays a key role in regulating primary and secondary productivity both on regional and global scales. As such, proper identification and characterization of nitrogen sources and their impacts on nutrient flux and trophic utilization is of prime concern in understanding biogeochemical responses in coastal ecosystems.
AN: 3600149
560 of 1521
TI: Modelling the nitrogen cycle in the Channel: A first approach
AU: Hoch,-T.; Menesguen,-A.; Bentley,-D.
AF: IFREMER, Cent. Brest, Dir. Environ. Littoral, Lab. Chim. Model. Cycles Nat., B.P. 70, 29280 Plouzane, France
CO: Channel Symp.: Fluxes and Processes Within a Macrotidal Sea, Brest (France), 2-7 Sep 1992
SO: CHANNEL-SYMPOSIUM:-FLUXES-AND-PROCESSES-WITHIN-A-MACROTIDAL-SEA.#SYMPOSIUM-MANCHE:-FLUX-ET-PROCESSUS-A-L'-ECHELLE. Chardy,-P.;Cabioch,-L.-eds. 1993 vol. 16, no. 5-6 pp. 643-651
ST: OCEANOL.-ACTA vol. 16, no. 5-6
LA: English
ER: M (Marine)
AB: A simple model of the nitrogen cycle in the Channel is proposed. Based on the long-term circulation, this box-model permits the description of the spring phytoplankton bloom in the whole Channel. Spring western thermal stratification has not been taken into account; consequently, the earliest phytoplanktonic development is observed in the eastern Channel, followed by the western, deeper part. This model also shows the influence of nutrient supply from the rivers on the Channel ecosystem, and particularly the influence of the River Seine on the chlorophyll concentrations along the eastern French coast. Comparison of calculated data with measurements shows a fairly good agreement in the eastern Channel but discrepancies are encountered for the western part. These problems are discussed and improvements of the model are proposed.
AN: 3599835
561 of 1521
TI: Role of plankton on the biogeochemical cycle of cadmium and vanadium in the eastern area of the Bay of Seine: First results.
OT: Role du plancton dans le cycle biogeochimique du cadmium et du vanadium en baie de Seine orientale: Premiers resultats
AU: Miramand,-P.; Bentley,-D.; Guary,-J.C.; Brylinski,-J.M.
AF: Lab. Biogeochim. Mar. Inst. Natl. Sci. Tech. Mer, Conserv. Natl. Arts Metiers, B.P. 324, 50103 Cherbourg Cedex, France
CO: Channel Symp.: Fluxes and Processes Within a Macrotidal Sea, Brest (France), 2-7 Sep 1992
SO: CHANNEL-SYMPOSIUM:-FLUXES-AND-PROCESSES-WITHIN-A-MACROTIDAL-SEA.#SYMPOSIUM-MANCHE:-FLUX-ET-PROCESSUS-A-L'-ECHELLE. Chardy,-P.;Cabioch,-L.-eds. 1993 vol. 16, no. 5-6 pp. 625-632
ST: OCEANOL.-ACTA vol. 16, no. 5-6
LA: French
ER: M (Marine)
AB: Cd and V were analyzed in planktonic species (zooplankton and diatoms), in flocks and in total seston (suspended materials) collected at eleven stations for seven sampling periods in the eastern area of the Bay of Seine. Cd concentrations measured in planktonic species of the Bay of Seine are identical to those measured in other oceanic areas, but V concentrations are generally higher. In the conditions of sampling, the role of both planktonic species and flocks in the horizontal fluxes of Cd and V in the Bay of Seine appears not to be important (Cd) or negligible (V) compared to non-living materials (tripton). Nevertheless, this study should be continued in periods of diatom blooms. Flocks which present high Cd and V concentration probably have an important role in the biogeochemical cycle for both elements in the Bay of Seine.
AN: 3599833
562 of 1521
TI: Beaver influences on the long-term biogeochemical characteristics of boreal forest drainage networks
AU: Naiman,-R.J.; Pinay,-G.; Johnston,-C.A.; Pastor,-J.
AF: Cent. Streamside Stud., AR-10, Univ. Washington, Seattle, WA 98195, USA
SO: ECOLOGY 1994 vol. 75, no. 4, pp. 905-921
LA: English
AB: Beaver (Castor canadensis) affect biogeochemical cycles and the accumulation and distribution of chemical elements over time and space by altering the hydrologic regime. Aerial photograph analyses of beaver activities on the 298-km super(2) Kabetogama Peninsula, Minnesota, were coupled with site-specific studies of soil and pore water concentrations of nutrients (nitrogen, phosphorus) and other ions (potassium, calcium, magnesium, iron, sulfate, chloride), nitrogen cycling processes (nitrogen fixation and denitrification), and biophysical environmental variables (vegetation, temperature, organic matter, soil structure, pH, and oxidation-reduction potential). Our analyses demonstrate that beaver influence the distribution, standing stocks, and availability of chemical elements by hydrologically induced alteration of biogeochemical pathways and by shifting element storage from forest vegetation to sediments and soils. Over the 63 yr of aerial photo records (1927-1988), beaver converted 13% of the peninsula to meadows and ponds. We argue that the net effect of beaver activities has been to translocate chemical elements from the originally inundated upland forest vegetation to downstream communities and to pond sediments. Since 1927 beaver activities have augmented the standing stock of chemical elements in the organic horizons by 20-295%, depending on the element. These influences are spatially extensive and long lasting, affecting fundamental environmental characteristics of boreal forest drainage networks for decades to centuries.
AN: 3599777
563 of 1521
TI: The role of the blue mussel Mytilus edulis in the cycling of nutrients in the Oosterschelde Estuary (The Netherlands)
AU: Prins,-T.C.; Smaal,-A.C.
AF: Netherlands Inst. Ecol., Cent. Estuar. Coast. Ecol., Vierstr. 28, 4401 EA Yerseke, Netherlands
SO: THE-OOSTERSCHELDE-ESTUARY-THE-NETHERLANDS:-A-CASE-STUDY-OF-A-CHANGING-ECOSYSTEM. Nienhuis,-P.H.;Smaal,-A.C.-eds. 1994 vol. 282-283 pp. 413-429
ST: HYDROBIOLOGIA vol. 282-283
LA: English
ER: B (Brackish)
AB: The fluxes of particulate and dissolved material between bivalve beds and the water column in the Oosterschelde estuary have been measured in situ with a Benthic Ecosystem Tunnel. On mussel beds uptake of POC, PON and POP was observed. POC and PON fluxes showed a significant positive correlation, and the average C:N ratio of the fluxes was 9.4. There was a high release of phosphate, nitrate, ammonium and silicate from the mussel bed into the water column. The effluxes of dissolved inorganic nitrogen and phosphate showed a significant correlation, with an average N:P ratio of 16.5. A comparison of the in situ measurements with individual nutrient excretion rates showed that excretion by the mussels contributed 31-85% to the total phosphate flux from the mussel bed. Ammonium excretion by the mussels accounted for 17-94% of the ammonium flux from the mussel bed. The mussels did not excrete silicate or nitrate. Mineralization of biodeposition on the mussel bed was probably the main source of the regenerated nutrients. From the in situ observations net budgets of N, P and Si for the mussel bed were calculated. A comparison between the uptake of particulate organic N and the release of dissolved inorganic N (ammonium + nitrate) showed that little N is retained by the mussel bed, and suggested that denitrification is a minor process in the mussel bed sediment. On average, only 2/3 of the particulate organic P, taken up by the mussel bed, was recycled as phosphate. A net Si uptake was observed during phytoplankton blooms, and a net release dominated during autumn. It is concluded that mussel beds increase the mineralization rate of phytoplankton and affect nutrient ratios in the water column. A comparison of N regeneration by mussels in the central part of the Oosterschelde estuary with model estimates of total N remineralization showed that mussels play a major role in the recycling of nitrogen.
AN: 3599148
564 of 1521
TI: Patterns of hydrological exchange and nutrient transformation in the hyporheic zone of a gravel-bottom stream: Examining terrestrial-aquatic linkages
AU: Triska,-F.J.; Duff,-J.H.; Avanzino,-R.J.
AF: U.S. Geol. Surv., Water Resour. Div., 345 Middlefield Rd., Menlo Park, CA 94025, USA
SO: FRESHWAT.-BIOL. 1993 vol. 29, no. 2, pp. 259-274
LA: English
ER: F (Freshwater)
AB: The terrestrial-aquatic interface beneath a riparian corridor was investigated as a region of hydrological and biological control of nutrient flux. Subsurface flow paths were defined from the channel toward the riparian zone and also from the riparian zone toward the channel using tracer-injection studies. Dissolved oxygen (DO) concentration in the hyporheic zone ranged from < 1.0 to 9.5 mg/l due to permeability variations in bankside sediments. DO concentration was related to the proportion of stream water in the lateral hyporheic zone, indicating that the channel water was the DO source. Both nitrification potential and channel exchange decreased with distance from the channel and were absent at sites lacking effective exchange, due to low DO. Field amendment of ammonium to an aerobic flow path indicated nitrification potential under natural hydrological conditions.
AN: 3597862
565 of 1521
TI: Role of interaction zones between surface and ground waters in DOC transport and processing: Considerations for river restoration
AU: Vervier,-P.; Dobson,-M.; Pinay,-G.
AF: Cent. Ecol. des Ressources Renouvelables, UPR CNRS 8211, 29 rue Jeanne Marvig, 31055 Toulouse Cedex, France
SO: FRESHWAT.-BIOL. 1993 vol. 29, no. 2, pp. 275-284
LA: English
ER: F (Freshwater)
AB: A study of dissolved organic carbon (DOC), nitrates and total dissolved phosphorus (TDP) concentrations, conductivity and bacterial numbers was undertaken in subsurface water of the Garonne River (France) under low-flow conditions. The velocity of subsurface flow through a 300-m gravel bar, during this study, was less than 43 m day super(-1). DOC, nitrates and TDP concentrations, conductivity and bacterial numbers fluctuated within the gravel bar with no discernible spatial pattern. Bacterial abundance was correlated with DOC concentration. Results were compared to a previous study of the Stillaguamish River (U.S.A.). These studies provide evidence that gravel bars are important in the processing of DOC by bacteria in the subsurface water. Bacterial activity is, in turn, determined by sources of DOC from upstream at high discharge, and by patchy local microhabitats at low discharge.
AN: 3597859
566 of 1521
TI: [Biological indicators of environmental contamination.]
OT: Indicateurs biologiques de la contamination de l'environnement
AU: Garrigues,-P.-(ed.)
AF: Univ. Bordeaux 1, F-33405 Talence Cedex, France
SO: ANALUSIS 1994 vol. 22, no. 1, pp. M9-M29
LA: French
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Numerous studies were recently carried out to examine biochemical, physiochemical and histological changes, and to evaluate the exposure of organisms to contaminants. Chemical analysis of different compartments of the environment (air, soil, water, organisms) give information on the presence/absence of a chemical compound and upon its biogeochemical cycle, but they do not give information on the impact of the toxic substance on organisms. Ecotoxicological tests are often unable to inform the toxicologist because of the low level of contaminants in the environment. Analytical measures of a given contaminant may confirm or deny the use of a biochemical indicator of pollution. A review of these techniques is made in this collection of papers.
AN: 3596043
567 of 1521
TI: A comparison of organic matter sources, diagenesis and preservation in oxic and anoxic coastal sites
AU: Cowie,-G.L.; Hedges,-J.I.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 447-451
LA: English
ER: M (Marine)
AB: Sediment cores and water-column particulate samples (from month-long sediment trap deployments over full-year periods) were recovered from two coastal environments; Dabob Bay (Washington State, U.S.A.) and Saanich Inlet (British Columbia, Canada). Lignin phenol, neutral sugar and amino acid compositions were determined for all samples, as were organic carbon and nitrogen contents. The sampling and analytical strategies were designed to provide molecular-level information on seasonal trends in organic matter sources and fluxes, as well as on the nature and magnitude of diagenetic processes occurring both in the water column and underlying sediments.
AN: 3596013
568 of 1521
TI: Degradation and oligomerization of syringic acid by distinctive ecological groups of fungi
AU: Bergbauer,-M.
AF: Inst. Biochem. Molek. Biol., Abt. Bot. Mikrobiol. Chem., Technische Univ. Berlin, 1000 Berlin 10, Franklinstr. 29 OE 5/1, FRG
SO: MICROB.-ECOL. 1991 vol. 21, no. 1, pp. 73-84
LA: English
ER: F (Freshwater)
AB: Forty-four terrestrial and aeroaquatic and aquatic fungi, including fifteen species causing white-rot, four species causing brown-rot, and some species causing soft-rot of wood, were tested for their ability to degrade the monomer syringic acid, which is released during decay of angiosperm lignin. None of the white- or brown-rot species caused any detectable degradation of syringic acid under the test conditions, however, six typical white-rot fungi strongly oligomerized syringic acid, both with and without cosubstrate. The main polymerization product was identified as a 1,3-dimethylpyrogallol oligomer by super(13)C-NMR. Other minor metabolic products were methylated and hydroxylated derivatives. Among the remaining fungi, Exophiala jeanselmei, Fusarium eumartii, and Paecilomyces variotii completely and rapidly degraded syringic acid (5 g/liter) within 48 to 100 hours. A further seven species were able to degrade syringic acid to some extent when glucose was added. Methylated and demethylated metabolic intermediates were identified by GC/MS.
AN: 3595831
569 of 1521
TI: Metabolic and structural changes in E. coli cells starved in seawater
AU: Papapetropoulou,-M.; Zoumbou,-K.; Nicolopoulou,-A.
AF: Environ. Microbiol. Div., Public Health Lab., Med. School, Univ. Patras, Greece
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K,-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-OF-RESEARCH-PROJECT-1992-1993.#CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K,-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROFETS-DE-RECHERCHE-1992-1993. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1993 no. 76 pp. 39-56
ST: MAP-TECH.-REP.-SER. no. 76
LA: English
ER: M (Marine)
AB: Thirteen Escherichia coli strains of different biotype isolated from bench cultures were followed for metabolic and structural changes during starvation in seawater at different time (0,2,6,9,16,21 days of starvation). Additionally sensitivity to antibiotics of the starved E. coli cells was performed over time on Mueller-Hinton agar. beta -Galactosidase activity of starved cells disappeared gradually with time. Nine (69.2%) of the E. coli strains lost the ability to decarboxylate lysine and seven (53.8%) to acidify melibiose. All E. coli strains acquired the ability to degrade gelatine at different time of starvation. Esterase 4, Esterase lipase, Leucine arylamidase and Lipase C14 increase during starvation while Alkaline and Acid phosphatase and Phosphoamidase decrease. Some of the strains lost their cytoplasmic proteins and in others the synthesis of the major outer membrane proteins was decreased. In one strain a large amount of 30 kDa proteins appeared. The sensitivity of E. coli strains to ampicillin, cephalothin, nalidixic acid, gentamicin, tobramycin, streptomycin and chloramphenicol increase slightly. In the case of tetracyclin, erythromycin, penicillin and vancomycin the difference in the diameter of zone of inhibition is minimum or zero. The traditionally used Bauer Kirby method has been proven to be inadequate for testing sensitivity of environmental strains. The understanding of the starvation-survival mechanism of pathogens related to Public Health is discussed.
AN: 3594876
570 of 1521
TI: [Gene expression in enteric bacteria in marine environments.]
OT: Expression genique chez les bacteries enteriques dans les conditions marines
AU: Gauthier,-M.J.; Breittmayer,-V.A.; Braux,-A.-S.
AF: INSERM Unite 303 "Mer et Sante", Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K,-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-OF-RESEARCH-PROJECT-1992-1993.#CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K,-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROFETS-DE-RECHERCHE-1992-1993. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1993 no. 76 pp. 9-38
ST: MAP-TECH.-REP.-SER. no. 76
LA: French
ER: M (Marine)
AN: 3594875
571 of 1521
TI: The survival of human enteric viruses in seawater
AU: Bosch,-A.; Gray,-M.; Diez,-J.M.; Gajardo,-R.; Abad,-F.X.; Pinto,-R.M.; Sobsey,-M.D.
AF: Dep. Microbiol., Univ. Barcelona, 08028 Barcelona, Spain
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K,-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-OF-RESEARCH-PROJECT-1992-1993.#CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K,-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROFETS-DE-RECHERCHE-1992-1993. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1993 no. 76 pp. 1-7
ST: MAP-TECH.-REP.-SER. no. 76
LA: English
ER: M (Marine)
AB: Human pathogenic viruses enter the marine environment primarily through the discharge of treated and untreated sewage into surface waters. Since current treatment practices do not provide virus-free effluents, enteric viruses are routinely discharged into estuarine and coastal waters. The critical question which arises, however, is whether or not these viruses can survive long enough and in high enough concentration to cause disease in individuals who are in contact with polluted recreational water or who consume contaminated seafood. The phenomenon that self purification processes are more pronounced in seawater than in river water has been reported by several authors. However, there appears to be no consensus on the nature of the factor(s) responsible for the virucidal capacity of seawater. Several observations demonstrate the potential involvement of native marine microorganisms in the inactivation of viruses in marine habitats, although data on the successful isolation of microorganisms with virucidal properties are scarce. Additionally, the ability of bacteria to inactivate viruses is usually lost while subculturing the bacteria in the laboratory. The present report deals with the effect of different types of seawater on the survival of human enteric viruses, and the influence of the presence of marine bacteria on the virucidal capacity of seawater.
AN: 3594874
572 of 1521
TI: Biogeochemical cycles of specific pollutants (activity K), survival of pathogens. Final reports on research project (1992-1993).
OT: Cycles biogeochemiques de polluants specifiques (activite K), survie des pathogenes. Rapports finaux sur les projets de recherche (1992-1993)
CA: UNEP Mediterranean Action Plan, Athens (Greece)
SO: MAP-TECH.-REP.-SER. ATHENS-GREECE UNEP 1993 no. 76, 65 pp
LA: English
ER: M (Marine)
AN: 3594873
573 of 1521
TI: The distribution of colloids in the North Atlantic and Southern Oceans
AU: Wells,-M.L.; Goldberg,-E.D.
AF: Inst. Mar. Sci., Earth and Mar. Sci. Build., Univ. California, Santa Cruz, CA 95064, USA
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 2, pp. 286-302
LA: English
ER: M (Marine)
AB: The concentrations and size distributions of small (<200 nm) colloids were measured at three stations in the North Atlantic and two stations in the Southern Ocean. The stations were chosen to cover a range of oceanographically distinct regimes, from highly productive nearshore environments to oligotrophic open-ocean waters. Colloid number concentrations decreased appreciably from the surface to similar to 150-m depth at three of these stations. Concentrations in deep waters of the North Atlantic were high but erratic, suggesting that colloid abundance is regulated by rapid rates of reactions. The colloids were mainly organic and their immediate sources appear to include both autotrophic and heterotrophic activity as well as sediment resuspension. Transmission electron microscope examination of colloid size distributions and morphology indicates that aggregation is the principal removal mechanism for these colloids. Evidence from the cumulative size spectra of small colloids indicates that colloid aggregation is most intense in vertically delineated zones near the surface, around the main thermocline ( similar to 1,000-1,500 m), and in bottom waters. These findings show that the marine colloidal state is abundant but discontinuous in both space and time throughout a wide range of oceanographic environments.
AN: 3594831
574 of 1521
TI: Reassessment of the oceanic residence time of phosphorus
AU: Ruttenberg,-K.C.
AF: Dep. Mar. Chem. and Geochem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 405-409
LA: English
ER: M (Marine)
AB: Phosphorus (P) is an essential nutrient for the growth of all organisms and is believed to limit marine productivity, especially on geologic time scales. As a result of the link between marine photosynthetic productivity and atmospheric CO sub(2), phosphorus along with other nutrients present in short supply in the euphotic zone have been cited as potential players in the ocean's role in climate change. This link has been referred to as the "nutrient-CO sub(2)" connection. Model simulations which aim to quantify the role of oceanic nutrient inventories in promoting or enhancing climate change rely on the most currently formulated element budgets for the ocean. In this paper significant modifications to the currently accepted marine phosphorus budget are proposed. The modified P budget presented here required a reassessment of phosphorus residence time in the ocean, and a concomitant review of the role of P as a potential player in climate change over glacial-interglacial time scales.
AN: 3592705
575 of 1521
TI: Sediment-trap experiments in the central and western Ross Sea, January and February 1990
AU: Dunbar,-R.B.; Mucciarone,-D.A.; Leventer,-A.
AF: Dep. Geol. Geophys., Rice Univ., Houston, TX 77251, USA
SO: ANTARCT.-J.-U.S. 1991 vol. 26, no. 5, pp. 115-117
LA: English
ER: M (Marine)
AB: As part of an interdisciplinary, multi-institutional study of the biogeochemical cycles of carbon and silicon on the Ross Sea continental shelf, we deployed both drifting and moored arrays of particle interceptor traps at three sites in the central and western Ross Sea during January and February, 1990. Particle transport and dissolution/degradation dynamics in the southern ocean water column control a variety of important processes including nutrient regeneration, delivery of food to benthic communities, and preservation of sediment records of climate change. Many features of the carbon and silicon cycles on the antarctic continental shelf are not observed in lower latitudes and appear to be controlled by a combination of unusual seasonality, great water depths, low temperatures, and high current energies. One of our goals is to establish budgets for surface production, vertical and horizontal transport, and seabed accumulation of important bioactive phases in this unique setting.
AN: 3592669
576 of 1521
TI: Phytoplankton sinking rates in the Ross Sea
AU: Close,-A.R.
AF: Grad. Progr. Ecol., Univ. Tennessee, Knoxville, TN 37996, USA
SO: ANTARCT.-J.-U.S. 1991 vol. 26, no. 5, pp. 151-152
LA: English
ER: M (Marine)
AB: As part of a coordinated, interdisciplinary study of the production of biogenic material at the surface, its flux and remineralization through the water column, and its accumulation in the sediments, we measured the sinking rates of suspended particulate matter in the Ross Sea in January and February 1990. Substantial deposits of diatoms occur in the sediments of the Ross Sea, and these deposits generally are composed of intact phytoplankton cells. One of our hypotheses in this program was that the vertical flux of phytoplankton from the ice-edge bloom was large relative to less productive regions, and we wanted to know whether this flux was continual or episodic in time (i.e., a large pulse of intact cells sink near the end of the growing season). If the latter were true, it would have significant implications for the biogeochemical cycles of biogenic elements (carbon, nitrogen, silicon) as well as food web dynamics.
AN: 3592662
577 of 1521
TI: Testing the microbial loop concept by comparing mesocosm data with results from a dynamical simulation model
AU: Baretta-Bekker,-J.G.; Riemann,-B.; Baretta,-J.W.,; Koch-Rasmussen,-E.
AF: Ecol. Modelling Cent., Joint Dep. Water Qual. Inst. and Danish Hydraul. Inst., Agern Alle 11, DK-2970 Hoersholm, Denmark
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 106, no. 1-2, pp. 187-198
LA: English
ER: M (Marine)
AB: Data from marine enclosures were compared with model results from the European Regional Seas Ecosystem Model (ERSEM). The simulation runs were performed with the December 1992 (V5.1) version of the pelagic submodel of ERSEM. The aim of the experiment was to verify the microbial loop as implemented in ERSEM against direct observations from marine enclosures. Initial conditions of the state variables for the model runs were derived from the same data. In general, the model results tracked the measured data indicating the model concept and implementation to be realistic. In contrast, the simulated concentrations of nitrate and phosphate in the nutrient-enriched bag stayed higher than observed, indicating the necessity of including mechanisms to allow for luxury uptake in the model description of the phytoplankton.
AN: 3592602
578 of 1521
TI: Phytoplankton dynamics in relation to the biogeochemical cycle of silicon in a coastal ecosystem of western Europe
AU: Ragueneau,-O.; De-Blas-Varela,-E.; Treguer,-P.; Queguiner,-B.; Del-Amo,-Y.
AF: URA CNRS 1513, Inst. Univ. Europeen de la Mer, Univ. de Bretagne Occidentale, BP452, F-29275 Brest Cedex, France
SO: MAR.-ECOL.-PROG.-SER. 1994 vol. 106, no. 1-2, pp. 157-172
LA: English
ER: M (Marine)
AB: The Bay of Brest, France, a typical semi-enclosed coastal ecosystem (159 km super(2)) of western Europe, was studied during spring 1992 with respect to the biogeochemical cycle of silicon. Three periods of nutrient and phytoplankton dynamics (chlorophyll a, biogenic silica, species compositon), were distinguished during spring 1992, each corresponding, respectively, to a bloom of Thalassiosira and Skeletonema costatum during early spring (April), Rhizosolenia during mid-spring (May) and Chaetoceros sociale during late spring (June). During each period the production of biogenic silica (the mean rate of spring biogenic silica production was 13 mmol Si/m super(2)/d), derived from super(14)C primary production measurements, size fractionation experiments and appropriate Si:C ratios, has been compared with the sum of the silicic acid inputs to the bay originating from rivers, from the adjacent Iroise Sea and from the sediments.
AN: 3592600
579 of 1521
TI: [Causes and effects of nutrient accumulation in the Baltic Sea.]
OT: Ursachen und Folgen der Naehrstoffakkumulation in der Ostsee
AU: Nehring,-D.
AF: Inst. Ostseeforsch., Seestr. 15, D-18069 Rostock-Warnemuende, FRG
CO: Vortragsveranstaltung des Arbeitsausschusses fuer Abwasserfragen im DFW, Rostock (FRG), 12 Sep 1991
SO: ACTUAL-PROBLEMS-IN-POLLUTION-OF-THE-BALTIC-SEA.#AKTUELLE-PROBLEME-DER-VERSCHMUTZUNG-DER-OSTSEE. HAMBURG-FRG DEUTSCHER-FISCHEREI-VERBAND-E.V. 1991 no. 54 pp. 48-62
ST: ARB.-DTSCH.-FISCH.-VERB. no. 54
LA: German
ER: M (Marine); B (Brackish)
AB: Long-term changes concerning the nutrient load of phosphate and nitrate accumulation in the Baltic Sea from 1969 to 1977 are reported in this study in reference to growing eutrophic conditions. The cause and effect of this situation along with prefective measurements are discussed.
AN: 3592559
580 of 1521
TI: [Seasonal and long-term changes of chemical-hydrographic data in the Kiel Bight.]
OT: Saisonale und langzeitliche Veraenderungen chemisch-hydrographischer Parameter in der Kieler Bucht
AU: Hansen,-H.-P.
SO: BIOLOGICAL-MONITORING-OF-THE-BALTIC-SEA-IN-THE-INSTITUTE-OF-MARINE-SCIENCE-KIEL-1985-1992.#DAS-BIOLOGISCHE-MONITORING-DER-OSTSEE-IM-INSTITUT-FUER-MEERESKUNDE-KIEL-1985-1992. Duiker,-J.C.-ed. 1993 no. 240 pp. 2-31
ST: BER.-INST.-MEERESKD.-CHRISTIAN-ALBRECHTS-UNIV.-KIEL no. 240
LA: German
ER: M (Marine); B (Brackish)
AB: The purpose of this study is to compare different long-term data periods for the hydrographic and chemical parameters in the Baltic Sea in order to find the causes in the degradation of this environment.
AN: 3592526
581 of 1521
TI: Patterns and processes in detritus-based stream systems
AU: Graca,-M.A.S.
AF: Dep. Zool. e Inst. Invest. Agua, Univ. Coimbra, 3049 Coimbra Codex, Portugal
SO: LIMNOLOGICA 1993 vol. 23, no. 2, pp. 107-114
LA: English
ER: F (Freshwater)
AB: Allochthonous organic matter entering streams has been referred to as a major source of energy for aquatic systems. Aquatic hyphomycetes are important in the release of nutrients locked in the structural plant material, apparently due to their ability to grow at low water temperatures. Detritus is ingested by animals only after colonization by these fungi. Some key processes in detritus-based stream systems are still unknown. For example, are the fungi the feeding target of detritivores or are the fungi important only as leaf modifiers? Why do detritivores select for particular detritus-colonizing fungal species? Do fungi play any role in the elimination of plant alellochemicals? All generalizations on detritus-based stream systems are derived from research carried out in meridional areas and little is known of its validity in warmer regions such as the mediterranean or tropical forests. It is therefore important to evaluate (1) the relative importance of allochthonous energy input in other systems and (2) the processes governing its entry into the aquatic food webs. Moreover, virtually nothing is known about how the systems may be affected by habitat modifications (e.g. afforestation of drainage basins with exotic species such as Pinus in Scotland and Wales or Eucalyptus in the Mediterranean and Brazil). Woodlands in general and tropical forests in particular are being destroyed at an alarming rate.
AN: 3592499
582 of 1521
TI: Nitrogen and energy loss in the marine teleost Lithognathus mormyrus (Linnaeus)
AU: Cockcroft,-A.C.; Du-Preez,-H.H.
AF: Zool. Dep., Univ. Port Elizabeth, PO Box 1600, Port Elizabeth 6000, South Africa
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1990 vol. 140, no. 3, pp. 159-171
LA: English
ER: M (Marine)
AB: Nitrogen excretion and assimilation efficiencies in Lithognathus mormyrus (Linnaeus), a marine teleost present in high-energy surf zones in Algoa Bay, South Africa, were determined under controlled laboratory conditions at 15, 20 and 25 degree C. Ammonia was the major form of nonfaecal nitrogen excreted by starved and fed L. mormyrus. Urea and amino acids were secondary excretory products. Ammonia excretion rates were temperature independent and the excretion rates of fed fish were significantly higher than starved fish at 20 and 25 degree C but not at 15 degree C. The mass component (b) of the mass/ammonia excretion equation was temperature independent and ranged from 0.590 to 0.669 and from 0.670 to 0.767 for starved and fed fish, respectively. The mean percentage of food energy lost via the dissolved nonfaecal excretory products (exogenous plus endogenous) was 4.12%. Assimilation efficiencies ranged from 71.89 to 98.78% for dry matter and from 96.89 to 99.88% on an energy basis. The combined nonfaecal and faecal energy loss was calculated at 10.11% of the ingested energy. The omnivorous ichthyofauna present in the surf zone ecosystem recycle 33 g N/m strip/yr. This constitutes <1% of total phytoplankton nitrogen requirements.
AN: 3591251
583 of 1521
TI: Nitrogen interchanges generated by biogeochemical processes in a Galician ria
AU: Prego,-R.
AF: Inst. Invest. Mar. (CSIC), Eduardo Cabello, 6, E-36208 Vigo, Spain
SO: MAR.-CHEM. 1994 vol. 45, no. 1-2, pp. 167-176
LA: English
ER: M (Marine); B (Brackish)
AB: The biogeochemistry of nitrogen in the ria of Vigo is approached on the basis of a box model which allows for calculation of the physical transport of nitrate, nitrite, ammonium and organic nitrogen, and the fluxes caused by photosynthesis, remineralisation and sedimentation of nitrogen. The ria of Vigo receives between 4 and 22 mol/s from exterior coastal water, a flux far greater than that of freshwater. The balance of organic nitrogen indicates that there is always an exportation to the outer ria, in the range of 0.5 to 5 mol/s. The enrichment of the incoming water is produced by photosynthetic activity in spring and summer, and by river and sediment contributions in winter. Inorganic nitrogen is only exported during the rainy season, when phytoplankton activity is low. During the rest of the year, the ria retains 3.5 mol/s of the total nitrogen received. As a result of these fluxes, the residence time of nitrogen in the ria varies between 15 and 97 days. In the spring and summer of 1986, photosynthesis of the ria of Vigo consumed 7.4 mol/s, 24% of which was derived from the remineralisation in the aphotic zone in the ria. Part of the synthesised PON is sedimented and remineralised on the continental shelf, or is reintroduced into the ria. This plays an important role in fertilising the area, not considered until now in Galician rias. Both remineralisations supply 40% of the inorganic nitrogen to the euphotic layer in the ria.
AN: 3591023
584 of 1521
TI: Stable isotopic structure of aquatic ecosystems
AU: Wada,-E.; Kabaya,-Y.; Kurihara,-Y.
AF: Mitsubishi Kasei Inst. Life Sci., 11 Minamiooya, Machida, Tokyo 194, Japan
SO: J.-BIOSCI. 1993 vol. 18, no. 4, pp. 483-499
LA: English
ER: B (Brackish)
AB: Isotopic biogeochemical and ecological structure can provide a new dimension for understanding material flows, and the simultaneous function and structure of an ecosystem. Distributions of delta super(13)C and delta super(15)N for biogenic substances in the Nanakita River estuary involving Gamo Lagoon in Japan were investigated to construct isotope biogeochemical and ecological structure for assessing fate and transfer of organic matter, and food web structure. The isotopic framework of the ecosystem was successfully described in a delta super(15)N-delta super(13)C map. In this estuary the variations of isotope ratios of biogenic substances were clearly explained by the mixing of land-derived organic matter, and marine-derived organic matter. A trophic-level effect of super(15)N enrichment was clearly observed. Organisms were classified into three groups depending upon the contribution of land-derived organic matter in a food chain. Almost all biota except mollusca in the lagoon depend on organic matter of marine origin. The contributions of both land and marine organic matter were comparable for mollusca in the lagoon.
AN: 3584947
585 of 1521
TI: The global insignificance of telluric input of dissolved trace metals (Cd, Cu, Ni and Zn) to ocean margins
AU: Martin,-J.M.; Thomas,-A.J.
AF: Inst. Biogeochim. Mar., URA CNRS 386, Ecole Norm. Super., 1 rue M. Arnoux, F-92120 Montrouge, France
CO: 12. Int. Symp. "Chemistry of the Mediterranean", Rovinj (Croatia), 18-23 May 1992
SO: 12TH-INTERNATIONAL-SYMPOSIUM-"CHEMISTRY-OF-THE-MEDITERRANEAN". Kniewald,-G.;Branica,-M.-eds. 1994 vol. 46, no. 1-2 pp. 165-178
ST: MAR.-CHEM. vol. 46, no. 1-2
LA: English
ER: M (Marine)
AB: A tentative mass-balance of dissolved trace metals (TM) in the global ocean margin is presented. Comparison of the various TM sources demonstrates the limited contribution of the telluric source (riverine and atmospheric), as compared to the oceanic input by upwelled water: marine inputs exceed telluric inputs by a factor of 2-3.5 for Cu, 2-7 for Zn, and of about 10 for Cd and Ni. Diagenetic TM release from deposited sediments, although likely for Cu and Zn, could not be quantified without ambiguity. Following intense water exchanges, TM are exchanged between the ocean margin and the open ocean very rapidly, and their short residence time is similar to the margin water residence time, i.e. about 1.3 yr.
AN: 3584561
586 of 1521
TI: Use of SAR in regional methane exchange studies
AU: Morrissey,-L.A.; Livingston,-G.P.; Durden,-S.L.
AF: NASA Ames Res. Cent., MS 242-4, Moffett Field, CA 94035-1000, USA
SO: INT.-J.-REMOTE-SENS. 1994 vol. 15, no. 6, pp. 1337-1342
LA: English
ER: F (Freshwater)
AB: Significant sources of uncertainty in global trace gas budgets are due to lack of knowledge concerning the areal and temporal extent of source and sink areas. Synthetic aperture radar (SAR) is particularly suited to studies of northern ecosystems because of its all-weather operating capability which enables the acquisition of seasonal data. As key controls on methane exchange, the ability to differentiate major vegetation communities, inundation, and leaf area index (LAI) with satellite and airborne SAR data would increase the accuracy and precision of regional and seasonal estimates of methane exchange. The utility of SAR data for monitoring key control on methane emissions from Arctic and boreal ecosystems is examined.
AN: 3581080
587 of 1521
TI: Organic volatile sulfur in lakes ranging in sulfate and dissolved salt concentration over five orders of magnitude
AU: Richards,-S.R.; Rudd,-J.W.M.; Kelly,-C.A.
AF: Macdonald Coll. McGill Univ., Dep. Microbiol., 21,111 Lakeshore Rd., Ste. Anne-de-Bellevue, PQ H9X 3V9, Canada
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 3, pp. 562-572
LA: English
ER: F (Freshwater)
AB: Organic volatile sulfur compounds (VSCs) were studied in six hypersaline lakes (southern Saskatchewan) and in dilute wetland ponds (Hudson Bay Lowlands, HBL). [SO sub(4) super(2-)] (0.0002-64 g/liter) and salt concentration (0.003-370 g/liter) ranged over 5 orders of magnitude. Organic VSC concentrations in ponds and lakes with [SO sub(4) super(2-)] < 7 g/liter were similar to those measured previously in freshwater lakes. Lakes with > 20 g SO sub(4) super(2-)/liter, however, had VSC concentrations several orders of magnitude higher. Dimethyl sulfide (DMS) was the dominant species, reaching a concentration of 3,050 nM in one salt lake - the highest concentration yet recorded. Carbonyl sulfide (COS), methanethiol (MSH), dimethyl disulfide (DMDS), and carbon disulfide (CS sub(2)) were also detected. In the salt lakes, [DMS], [MSH], and [total] VSC] were positively correlated (P < 0.05) to [SO sub(4) super(2-)] but not to dissolved salt concentration (P < 0.05). The estimated mean atmospheric flux from the salt lakes ranged from 2 to 590 mu mol S/m super(2)/d. The low end of this range is similar to fluxes from Canadian Shield lakes and the ocean; the high end is 500 x higher. Fluxes from the HBL ponds (0.4 - 4 mu mol S/m super(2)/d) were similar to fluxes from Canadian Shield lakes.
AN: 3580947
588 of 1521
TI: Cycling and accumulation of biogenic silica and organic matter in high-latitude environments: The Ross Sea
AU: DeMaster,-D.J.; Dunbar,-R.B.; Gordon,-L.I.; Leventer,-A.R.; Morrison,-J.M.; Nelson,-D.M.; Nittrouer,-C.A.; Smith,-W.O.,Jr.
AF: Dep. Mar., Earth., Atmos. Sci., North Carolina State Univ., Raleigh, NC 27695-8208, USA
SO: OCEANOGRAPHY 1992 vol. 5, no. 3, pp. 146-153
LA: English
ER: M (Marine)
AB: The focus of this high-latitude study has been to quantify the cycles of Si and organic C in the water column and seabed and to identify the primary location of the fractionation between fluxes of biogenic silica and organic matter. Measurements of uptake and regeneration rates were made for organic and siliceous phases throughout the upper 150 m of the water column. Particle traps were used to characterize changes in the nature of the biogenic particles within the water column at depths of 231 and 500-750 m below the ocean surface. Box cores and kasten cores were collected from the seabed to evaluate regeneration of biogenic phases below the sediment-water interface as well as accumulation rates of biogenic material in the sediment column. The Ross Sea was chosen because it typifies many Antarctic settings and is characterized by significant biogenic production and seabed accumulation, relatively confined boundaries, water circulation that is reasonably well understood (as compared with the complex dynamics of the Polar Front), and close proximity to a major Antarctic support facility (McMurdo Station). A two-year time-series study has been conducted in an effort to minimize potential biases from short-term blooms and episodic changes in circulation and sedimentation. This paper describes several unique aspects of nutrient and carbon cycling in the high-latitude environment of the Ross Sea.
AN: 3580339
589 of 1521
TI: Physiological limitations on phytoplankton productivity in the ocean
AU: Falkowski,-P.G.; Greene,-R.M.; Geider,-R.J.
AF: Oceanogr. Atmos. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: OCEANOGRAPHY 1992 vol. 5, no. 2, pp. 84-91
LA: English
ER: M (Marine)
AB: The question of what limits primary productivity and phytoplankton biomass in natural waters has occupied oceanographers and limnologists for more than a century. The earliest oceanographers recognized that this issue is key to understanding the regulation of both aquatic food chains and biogeochemical cycles. Traditionally, phytoplankton ecologists have been imbued with the concepts of the light, nitrogen and temperature limitation as they relate to the critical depth model, Michaelis-Menten kinetics, and thermodynamic constraints on growth. The recent suggestion that a micronutrient, such as iron, limits phytoplankton biomass or production in vast portions of the world's oceans has been met with some skepticism. To a large extent the difficulty in determining what limits primary production stems both from methodological deficiencies and semantic confusion. The identification of limiting factors has been based on primarily three techniques: correlative inference, experimental manipulation, and simulation modeling. Here we examine the concepts of limiting factors and explore the possibility of using in vivo chlorophyll fluorescence (a biophysical signal), in conjunction with molecular markers, to identify or diagnose factors limiting phytoplankton growth and production in the ocean.
AN: 3580332
590 of 1521
TI: Measurement of dissolved organic carbon and nitrogen in natural waters
AU: Williams,-P.M.
AF: Mar. Res. Div., Scripps Inst. Oceanogr., Univ. Califonia, La Jolla, CA 92093-0218, USA
SO: OCEANOGRAPHY 1992 vol. 5, no. 2, pp. 107-116
LA: English
ER: M (Marine)
AB: The potential impact of elevated dissolved organic carbon (DOC) and nitrogen (DON) concentrations on the biogeochemical cycling of organic matter in the oceans is profound. Yet we are at an impasse in obtaining accurate measurements of DOC and DON. A Workshop in Seattle (15-19 July 1991) was conceived to bring order to the present uncertainties in these measurements and to make explicit recommendations for future analytical protocols and experimentation.
AN: 3580219
591 of 1521
TI: Marine calcification as a source of carbon dioxide: Positive feedback of increasing atmospheric CO sub(2)
AU: Frankignoulle,-M.; Canon,-C.; Gattuso,-J.-P.
AF: Univ. Liege, Lab. Oceanol., Inst. Chim., Bat B6, B 4000 Sart Tilman, Belgium
SO: LIMNOL.-OCEANOGR. 1994 vol. 39, no. 2, pp. 458-462
LA: English
ER: M (Marine)
AB: Calcification is a well-recognized source of CO sub(2) to the surrounding water and thus a potential source of atmospheric CO sub(2) due to chemical equilibria involving the CO sub(2) species. The released CO sub(2): precipitated carbonate ratio ( psi ) has recently been estimated to be 0.6 in seawater (taking into account the buffering capacity of the latter). We report an analytical expression enabling the computation of this ratio. Calculations show that the amount of CO sub(2) that must be released to equilibrate seawater increases with increasing partial pressure of CO sub(2) in seawater (pCO sub(2)), which results from human impact on atmospheric CO sub(2). We show that at 15 degree C psi increased from 0.55 during the time of glaciation to 0.67 at present and would increase to 0.84 for a pCO sub(2) of 1,000 mu atm. Doubling the preindustrial pCO sub(2) value results in a total CO sub(2) source of similar to 5 Gt C (taking into account the described buffering effect).
AN: 3580070
592 of 1521
TI: Metal accumulation within salt marsh environments: A review
AU: Williams,-T.P.; Bubb,-J.M.; Lester,-J.N.
AF: Environ. and Water Resour. Eng. Section, Civ. Eng. Dep., Imperial Coll. Sci., Technol. and Med., London SW7 2BU, UK
SO: MAR.-POLLUT.-BULL. 1994 vol. 28, no. 5, pp. 277-290
LA: English
ER: M (Marine); B (Brackish)
AB: A comprehensive assessment of the chemical and physical factors affecting metal accumulation and cycling within salt marshes is presented. The effects that changes in physico-chemical properties (redox potential, salinity, pH, etc.) have upon metal mobility, speciation and consequent biological availability are described together with the implications for salt marsh habitat loss. Salt marshes act as very efficient sinks for metal contaminants although metal concentrations in halophytes do not generally reflect environmental contamination levels. Marine angiosperms, particularly Zostera marina, do however, reflect external metal concentrations and can therefore be used as biomonitors. Evidence suggests that the concentration of heavy metals in the sediments of most estuaries is not sufficiently high to cause ill effects to salt marsh plants although further investigations are necessary to assess potential threats of pollutants upon the health of these intertidal ecosystems.
AN: 3579535
593 of 1521
TI: Partitioning of Cu in estuarine waters, 1. Partitioning in a poisoned system
AU: Paulson,-A.J.; Curl,-H.C.,Jr.; Gendron,-J.F.
AF: Spokane Res. Cent., U.S. Bur. Mines, E. 315 Montgomery Ave., Spokane, WA 99207, USA
SO: MAR.-CHEM. 1994 vol. 45, no. 1-2, pp. 67-80
LA: English
ER: M (Marine)
AB: The importance of dissolved hydrophobic organic matter in controlling the partitioning of Cu between the dissolved and particulate phases in natural waters was determined. Estuarine particulate matter was suspended in two solutions: (1) filtered seawater, and (2) filtered seawater in which the hydrophobic organic matter had been removed. Radioactive Cu was then added to each suspension. The removal of hydrophobic dissolved organic matter resulted in a two-fold increase in the distribution coefficient (K sub(D)) of added radioactive Cu (from 10 super(4.50) to 10 super(4,81) l/kg). The partitioning of super(64)Cu in the suspensions was controlled by chemical processes dominated by complexation with particulate and dissolved organic matter.
AN: 3579501
594 of 1521
TI: SeaWiFS technical report series. Volume 1: An overview of SeaWiFS and ocean color
AU: Hooker,-S.B.; Firestone,-E.R.; Esaias,-W.E.; Feldman,-G.C.; Gregg,-W.W.
CA: National Aeronautics and Space Adm., Greenbelt, MD (USA). Goddard Space Flight Cent.
SO: 1992 28 pp
RN: NAS 1.15:104566-V-1, NASA-TM-104566-V-1 (115104566V1NASATM104566V1)
LA: English
ER: M (Marine)
AB: The purpose of this series of technical reports is to provide current documentation of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project activities, instrument performance, algorithms, and operations. This documentation is necessary to ensure that critical information related to the quality and calibration of the satellite data is available to the scientific community. SeaWiFS will bring to the ocean community a welcomed and improved renewal of the ocean color remote sensing capability lost when the Nimbus-7 Coastal Zone Color Scanner (CZCS) ceased operating in 1986. The goal of SeaWiFS, scheduled to be launched in August 1993, is to examine oceanic factors that affect global change. Because of the role of phytoplankton in the global carbon cycle, data obtained from SeaWiFS will be used to assess the ocean's role in this cycle, as well as other biogeochemical cycles. SeaWiFS data will be used to help elucidate the magnitude and variability of the annual cycle of primary production by marine phytoplankton and to determine the distribution and timing of spring blooms. The observations will help to visualize the dynamics of ocean and costal currents, the physics of mixing, and the relationships between ocean physics and large-scale patterns of productivity. The data will help fill the gap in ocean biological observations between those of the CZCS and the upcoming Moderate Resolution Imaging Spectrometer (MODIS) on the Earth Observing System-A (EOS-A) satellite.
AN: 3578864
595 of 1521
TI: Chemical fluxes and mass balances in a marine fish cage farm. 3. Silicon
AU: Holby,-O.; Hall,-P.O.J.
AF: Dep. Anal. and Mar. Chem., Univ. Goeteborg, S-412 96 Goeteborg, Sweden
SO: AQUACULTURE 1994 vol. 120, no. 3-4, pp. 305-318
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Fluxes and pathways of silicon in a marine rainbow trout (Oncorhynchus mykiss) cage farm were studied. The measured fluxes included those carried by fish food, juveniles, harvest, fish loss (death and escape), sedimentation from the cages, and benthic release measured with flux chambers in-situ. Two different types of Si mass balances for the farm were constructed. The mass balance according to the flux method was based on the measured fluxes and constructed for each of two consecutive growing seasons. The mass balance constructed according to the accumulation method was based on the total input and removal of Si to the cages of the farm since it was started, and the recovery of Si in the sediment originating from the farm. In both types of mass balances external input was the major source of Si, contributing a minimum of 55-80% of the total biogenic silica in the material collected in sediment traps below the farm and of the material accumulated in the farm-derived sediment. The Si removed from the farm with harvest contributed a very small part, similar to 0.3%, of the amount of Si supplied to the farm with fish food and juveniles. The loss of Si to the environment was 2.4 kg (1985), 2.5 kg (1986) and 2.5 kg (1980-86) for each ton of fish produced. On a seasonal basis, about 4.5% of the sedimented biogenic Si was returned in dissolved form from the sediment to the overlying water. This constituted about 0.3% of the biogenic Si content in the farm-derived sediment. The flux of reactive silicate from sediment below the fish farm was enhanced about 2.5 times compared to nearby sediments unaffected by the farm.
AN: 3578471
596 of 1521
TI: Comparison of the August-September 1991 and 1979 surface partial pressure of CO sub(2) distribution in the Equatorial Pacific Ocean near 150 degree W
AU: Goyet,-C.; Peltzer,-E.T.
AF: Woods Hole Oceanogr. Inst., Dep. Mar. Chem. and Geochem., Woods Hole, MA 02543, USA
SO: MAR.-CHEM. 1994 vol. 45, no. 4, pp. 257-266
LA: English
ER: M (Marine)
AB: The partial pressure of CO sub(2) (pCO sub(2)) in the surface seawater and marine air from 17 degree S to 22 degree N near 151 degree W (WOCE leg P-16c) during the period from August 31 to September 29, 1991, were measured continually. The surface seawater pCO sub(2) showed large latitudinal variation with a maximum of 425 mu atm near the equator. These results are compared with pCO sub(2) measurements in 1979, in the same area and same months. The short-scale (temporal and spatial) variations in surface seawater pCO sub(2) ( plus or minus 6.1 mu atm) do not allow us to unequivocally quantify the variation in Delta pCO sub(2) (pCO sub(2) super(sea)-pCO sub(2) super(air)) between the years 1979 and 1991 due to oceanic uptake of fossil fuel CO sub(2). However, the data suggest that this ocean area might be a stronger source of CO sub(2) for the atmosphere than may be expected from results of ocean models.
AN: 3573487
597 of 1521
TI: Iron oxidation kinetics in an acidic alpine lake
AU: Barry,-R.C.; Schnoor,-J.L.*; Sulzberger,-B.; Sigg,-L.; Stumm,-W.
AF: Dep. Civ. Environ. Eng., Univ. Iowa, Iowa City, IA 52242, USA
SO: WATER-RES. 1994 vol. 28, no. 2, pp. 323-333
LA: English
ER: F (Freshwater)
AB: Four experiments were performed to assess the role of homogeneous, heterogeneous, biological and photochemical processes in the oxygenation of ferrous iron in aquatic ecosystems. Experiments were carried out at Lake Cristallina, Ticino, Switzerland, and in the laboratory. Rate constants are presented for homogeneous oxygenation in lakewater, for oxygenation by lake sediment under sterile and non-sterile conditions and for heterogeneous oxygenation in the presence of TiO sub(2), MnO sub(2), Fe sub(2)O sub(3), Al sub(2)O sub(3) and SiO sub(2). It was found that, on a surface area adjusted basis, TiO sub(2), MnO sub(2) and Fe sub(2)O sub(3) were three orders of magnitude more effective in accelerating oxygenation than Al sub(2)O sub(3) and SiO sub(2), suggesting that these minerals form strong, inner sphere complexes with Fe(II) in the pH range 4-6. Sterilization by gamma irradiation reduced oxygenation rate in the presence of lake sediment by two orders of magnitude on a surface area adjusted basis. Oxygenation in the presence of 0.44 mu m filtered lakewater was not appreciably different from that in distilled water. In situ experiments showed that oxygenation rate increased in the presence of sunlight. The heterogeneous rate constant for iron oxidation with lake sediment was 4.9 x 10 super(14)/M super(2)/atm/s/m super(2) and with pure minerals ranged from 1.8 x 10 super(10) to 5.3 x 10 super(13)/M super(2)/atm/s/m super(2).
AN: 3571436
598 of 1521
TI: Response of a coupled ocean-atmosphere model to increasing atmospheric carbon dioxide
AU: Manabe,-S.; Stouffer,-R.J.; Spelman,-M.J.
AF: Geophys. Fluid Dyn. Lab./NOAA, Princeton Univ., P.O. Box 308, Princeton, NJ 08542, USA
SO: AMBIO 1994 vol. 23, no. 1, pp. 44-49
LA: English
ER: M (Marine)
AB: This study investigates the response of a climate model to a 1% per year increase of atmospheric carbon dioxide. The model is a general circulation model of the coupled ocean-atmosphere-land surface system, with a global computational domain, smoothed geography, and seasonal variation of insolation. The simulated increase of sea-surface temperature is very slow in the northern North Atlantic and the Circumpolar Ocean of the Southern Hemisphere where the vertical mixing of water penetrates very deeply and the rate of deep water formation is relatively fast. Extending this work, we investigated the transient responses of the coupled model to the doubling and quadrupling of atmospheric CO sub(2), over the period of several centuries. During the entire 500-yr period of the experiment, the global mean surface air temperature increases almost 3.5 degree C when CO sub(2) is doubled, and 7 degree C when it is quadrupled. In the latter experiment, the thermal structure and dynamics of the model oceans undergo drastic changes, such as cessation of the thermohaline circulation in most of the model oceans, and substantial deepening of the thermocline, especially in the North Atlantic. These changes prevent the ventilation of the deeper layer of the oceans and, if they occurred in reality, could have a profound impact on the carbon cycle and biogeochemistry of the coupled ocean-atmosphere system.
AN: 3571406
599 of 1521
TI: Planetary metabolism: Understanding the carbon cycle
AU: Moore,-B.,III; Braswell,-B.H.,Jr.
AF: Inst. Study Earth, Oceans, and Space, Univ. New Hampshire, Morse Hall, Durham, NH 03824-3525, USA
SO: AMBIO 1994 vol. 23, no. 1, pp. 4-12
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Biological systems are intimately involved in the transfers of energy and materials around our planet, affecting the geochemistry and other physical properties of the atmosphere, the land surface, and the oceans and their sediments. Fossil-fuel combustion, land use and other human activities are, increasingly, disrupting these natural biogeochemical cycles and processes, with the potential for far-reaching consequences; for example, changes in atmospheric composition affecting the global heat balance. The carbon, nitrogen and sulfur cycles are of particular importance to the functioning of the biosphere, and are also closely linked to the physical climate system. Within IGBP, the global-scale modelling effort is initially focussed on the carbon cycle: this is poorly understood-yet is critical to estimating future levels of CO sub(2) and other greenhouse gases, and their direct and indirect interactions with the biosphere. To assist in determining the factors that influence the atmospheric lifetime of CO sub(2), the concept of a single half-life (T sub(1/2)) is applied to three simple ocean carbon-cycle models and a model of global terrestrial carbon cycling. We find significant differences due to the inclusion of the terrestrial model and the nature of the assumptions made about the possible terrestrial fertilization response: estimates of T sub(1/2) vary between 92 years (no allowance for terrestrial effects) to 27 years (with both terrestrial regrowth plus fertilization). The range of these values raises further scientific questions, and has implications for policy development.
AN: 3571405
600 of 1521
TI: Degradation processes of phytoplankton in a eutrophic bay with particular reference to the chlorophyll a pigment composition of suspended and sinking particles.
OT: Kaisuichu-kendakurushi to chikoryushi no kurorofiru-a-rui sosei kara mita fueiyo-naiwan ni okeru shokubutsu purankuton no bunkai katei
AU: Sakoh,-H.; Matsuda,-O.; Yamamoto,-T.
AF: Fac. Appl. Biol. Sci., Hiroshima Univ., Higashi-Hiroshima, 724 Japan
SO: J.-FAC.-APPL.-BIOL.-SCI.-HIROSHIMA-UNIV.-HIRODAI-SEIBUTSUSEISANGAKUBU-KIYO 1993 vol. 32, no. 2, pp. 79-86
LA: Japanese
ER: M (Marine)
AB: Physiological condition of phytoplankton can be estimated from both quantitative and qualitative analyses of photosynthetic pigments. In this study, the process of chlorophyll a degradation in an enclosed eutrophic bay were investigated using high-performance liquid chromatography (HPLC). Chlorophyll a and its derivatives were classified into chl.a, chl.a isomers (chl.a'-1, 2, 3) and pheopigments by the use of reverse-phased HPLC. Resulted pigment compositions were compared between suspended particles, sinking particles and surface sediment in Etauchi Bay. Chl.a was more abundant in suspended particles than in sinking particles, while pheopigments in both particles accounted for only less than 30%.
AN: 3570441
601 of 1521
TI: Rapid cycling of high-molecular-weight dissolved organic matter in the ocean
AU: Amon,-R.M.W.; Benner,-R.
AF: Mar. Sci. Inst., Univ. Texas at Austin, Port Aransas, TX 78373-1267, USA
SO: NATURE 1994 vol. 369, no. 6481, pp. 549-552
LA: English
ER: M (Marine)
AB: Dissolved organic matter (DOM) in the ocean is one of the largest active reservoirs of organic carbon on Earth. It is important to understand the processes by which DOM is recycled, particularly as changes in the oceanic DOM pool could affect atmospheric carbon dioxide concentrations on timescales of 1,000 to 10,000 years. It is commonly believed that low-molecular-weight material, which comprises 65-80% of DOM, is rapidly remineralized, and that high-molecular-weight material is refractory. But the average age of DOM in the deep ocean is about 6,000 years which implies that a large proportion of the DOM cycles only very slowly. Here we present a study of the relative bioavailability of low- and high-molecular weight DOM in water samples taken from the northern Gulf of Mexico during a diatom bloom. Bacterial growth and respiration in the presence of high-molecular-weight DOM were respectively three and six times greater than for low-molecular-weight material. Although both of these pools undoubtedly contain mixtures of compounds with varying reactivities and turnover times, our results demonstrate that the bulk of oceanic DOM comprises small molecules that cycle slowly and are relatively unavailable to microorganisms.
AN: 3569238
602 of 1521
TI: Stable isotopic structure of aquatic ecosystems
AU: Wada,-E.; Kabaya,-Y.; Kurihara,-Y.
AF: Cent. Ecol. Res., Kyoto Univ., 4-1-23 Shimosakamoto, Otsu, Shiga 520-01, Japan
SO: J.-BIOSCI. 1993 vol. 18, no. 4, pp. 483-499
LA: English
ER: B (Brackish)
AB: Isotopic, biogeochemical and ecological structure can provide a new dimension for understanding material flows, and the simultaneous function and structure of an ecosystem. Distributions of delta super(13)C and delta super(15)N for biogenic substances in the Nanakita River estuary involving Gamo lagoon in Japan were investigated to construct isotope biogeochemical and ecological structure for assessing fate and transfer of organic matter, and food web structure. The isotopic framework of the ecosystem was successfully described in a delta super(15)N- delta super(13)C map. In this estuary the variations of isotope ratios of biogenic substances were clearly explained by the mixing of land-derived organic matter, and marine-derived organic matter. A trophic-level effect of super(15)N enrichment was clearly observed. Organisms were classified into three groups depending upon the contribution of land-derived organic matter in a food chain. Almost all biota except mollusca in the lagoon depend on organic matter of marine origin. The contributions of both land and marine organic matter were comparable for mollusca in the lagoon.
AN: 3569192
603 of 1521
TI: Chlorophyll, photosynthesis and new production in the Southern California Bight
AU: Eppley,-R.W.
AF: Mar. Life Res. Group, Scripps Inst. Oceanogr., Univ. California, San Diego, La Jolla, CA 92093-0218, USA
SO: PROG.-OCEANOGR. 1992 vol. 30, no. 1-4, pp. 117-150
LA: English
ER: M (Marine)
AB: The study of phytoplankton distributions and processes in these waters has been stimulated in recent years by the synoptic views of surface pigment afforded by the Coastal Zone Color Scanner (CZCS) aboard the NIMBUS-7 satellite; by rapid developments in bio-optical oceanography toward the estimation of in sity photosynthetic rate; by use of sediment traps and geochemical tracers to determine the flux of organic matter from the euphotic zone; and by measurements of new production based on the utilization of nitrate by the plankton. The evolution and rationale of the Joint Global Ocean Flux Study of ocean biogeochemical cycles and ocean climate change serve to focus much of the work. In that context, a major goal is to assess new/export production on large time and space scales accessible to date only by remote sensing.
AN: 3569123
604 of 1521
TI: Biodegradable substances in lake sediments and their relation to sediment microbiological activity and phosphorus recycling
AU: Matinvesi,-J.; Heinonen-Tanski,-H.
AF: Natl. Board Waters and Environ., Dist. Off. Kuopio, Box 49 SF-70101 Kuopio, Finland
SO: AQUA-FENN. 1992 vol. 22, no. 2, pp. 193-200
LA: English
ER: F (Freshwater)
AB: Phosphorus recycling from lake sediments is a complex process, that depends, on physical chemical, and microbiological conditions. The authors measured ignition loss, BOD sub(7) tot-N, tot-P, tot-Fe, and some microbiological parameters in lake sediment samples. There is a good correlation between the number of bacteria, phosphatase enzyme activities, and the amount of BOD sub(7) in top sediments. Top sediment profiles were taken from the deepest part of six central Finnish lakes representing six different trophic states, and each profile was divided into three layers. The phosphatase enzyme activity, the number of acetic-acid-, ferric-phosphate-, and tricalcium-phosphate-utilizing bacteria, and the levels of organic substances were highest in the top layer of every sediment profile. Organic phosphatase enzyme activity levels were 10 to 25 times higher than inorganic phosphatase enzyme activity levels in the top sediment subsamples. The amount of BOD sub(7) in the top layer of the sediment correlated to the amount of total phosphorus in the very top layer (0-1.5 cm). Microbiological phosphate mineralization from organic substances may be the main reason for the inner load of phosphorus in the lakes of central Finland.
AN: 3568643
605 of 1521
TI: Biogeochemical cycling in the northwestern Indian Ocean: A brief overview
AU: Burkill,-P.H.; Mantoura,-R.F.C.; Owens,-N.J.P.
AF: Plymouth Mar. Lab., Prospect Pl., The Hoe, Plymouth PL1 3DH, UK
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 643-649
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The northwestern Indian Ocean may be defined conveniently as the ocean basin that is bounded by the African and Asian land masses to the west and north, and the Indian subcontinent and the Maldives to the east. With a southern boundary chosen arbitrarily as the Equator, its area is about 6.2 x 10 super(6) km super(2). Although it is one of the smallest ocean basins, it contains a diversity of biogeochemical provinces such as eutrophic, oligotrophic, upwelling and reduced oxygen environments. The presence of such diversity within a small ocean basin has made it an attractive location for biogeochemical studies. Many of these have been reviewed. In this issue, we report the results of more recent biogeochemical studies carried out abroad R.R.S. Charles Darwin, R.V. Meteor and O.R.V. Sagar Kanya during 1986-88.
AN: 3567041
606 of 1521
TI: Nitrogen biogeochemical cycling in the northwestern Indian Ocean
AU: Mantoura,-R.F.C.; Law,-C.S.; Owens,-N.J.P.; Burkill,-P.H.; Woodward,-E.M.S.; Howland,-R.J.M.; Llewellyn,-C.A.
AF: Plymouth Mar. Lab., Prospect Pl., West Hoe, Plymouth, PL1 3DH, Devon, UK
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 651-671
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The vertical distribution and fine scale structure of nitrate (NO sub(3)), nitrite (NO sub(2)), nitrous oxide (N sub(2)O), phosphate (PO sub(4)), oxygen (O sub(2)) and chlorophyll a (chl a) were determined in the North Western Indian Ocean (NWIO) along a meridional section (67 degree E) from the Equator to the Gulf of Oman using an Autoanalyser for micromolar levels of nutrients, and chemiluminescence and gas chromatographic methods for nanomolar levels of NO sub(3) and NO sub(2) and N sub(2)O respectively. Three biogeochemically contrasting regimes were investigated: (1) the highly oligotrophic nutrient-depleted subtropical gyre; (2) the monsoonal upwelling of nutrient-rich intermediate waters off the southeastern Arabian Coast; and (3) the denitrifying O sub(2)-depleted zone (ODZ; ca 150-1200 m depth) in the Arabian Sea.
AN: 3567040
607 of 1521
TI: Maintenance of the low-oxygen layer in the central Arabian Sea
AU: Olson,-D.B.; Hitchcock,-G.L.; Fine,-R.A.; Warren,-B.A.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Univ. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 673-685
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: An intermediate depth layer, approximately 1 km thick, in the northwestern Indian Ocean contains essentially no detectable dissolved oxygen. Previous suggestions for primary causes of this feature have been: (a) very slow movement within the layer, allowing a long time for organic decomposition to consume the oxygen; (b) very large local consumption rates, resulting from enormous productivity in the surface layer; or (c) low oxygen concentrations in the waters entering the layer from the south, due to their long transit from their sea-surface sources. Observations reported here of a transient anthropogenic trace gas, trichlorofluoromethane (F-11 or freon 11), however, demonstrate that the residence time for water in the low-oxygen layer is not especially long, about 10 years. Concurrent summertime measurements of surface productivity, while high, preclude an exceptional mean consumption rate at depth. An oxygen budget for the layer supports the idea that the near-zero concentration is maintained by moderate consumption applied to waters with initially low oxygen concentration that pass through the layer at moderate speed.
AN: 3567039
608 of 1521
TI: Activity of the respiratory electron transport system and respiration rates within the oxygen minimum layer of the Arabian Sea
AU: Naqvi,-S.W.A.; Shailaja,-M.S.
AF: Natl. Inst. Oceanogr., Dona Paula, Goa 403 004, India
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 687-695
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Measurements of the activity of the respiratory electron transport system (ETS) at 15 stations in the Arabian Sea during the northeast monsoon (December 1988) yield high respiration rates that do not correlate with the trends in primary productivity. The rates are unlikely to be sustained by the supply of carbon associated with the sinking particles alone, and seem to suggest a major role for dissolved and/or suspended organic matter in fuelling oxygen consumption and denitrification. The data are utilized to compute a denitrification rate of 24-33 Tg N y super(-1) in the Arabian Sea. This estimate agrees with the estimate based on the exports of nitrate deficits outside the denitrification zone. The ventilation time of the denitrifying layer is calculated as similar to 1 year.
AN: 3567038
609 of 1521
TI: Size-fractionated primary production and nitrogen assimilation in the northwestern Indian Ocean
AU: Owens,-N.J.P.; Burkill,-P.H.; Mantoura,-R.F.C.; Woodward,-E.M.S.; Bellan,-I.E.; Aiken,-J.; et-al.
AF: Plymouth Mar. Lab., Prospect Pl., The Hoe, Plymouth, PL1 3DH, UK
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 697-709
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Rates of phytoplankton production and nitrogen assimilation were measured at various stations along a transect in the northwestern Indian Ocean, from near the equator, northwards into the upwelling system off the Arabian peninsula, during September-October 1986. The measurements were made using in situ incubation techniques with the simultaneous use of super(14)C and super(15)N isotopes. Samples were fractionated after the incubations into three size classes: 0.2-0.8 mu m, 0.8-5.0 mu m, and >5.0 mu m for the super(14)C incubations; and <5.0 mu m and >5.0 mu m for the super(15)N incubations. The assimilation of nitrate and ammonium was measured. These measurements were supported by a detailed description of the horizontal and vertical distributions of chlorophyll, temperature and underwater light field, by the deployment of a towed undulating oceanographic recorder. Rates of primary production ranged from approximately 0.5 g C m super(-2)day super(-1) at the equator, reducing to <0.3 in the oligotrophic gyre in the central northern Indian Ocean, and to >2.5 in the upwelling region off the coast of Oman; total nitrogen assimilation followed a similar pattern. Very significant variations in the size distribution of the activity of the plankton were observed. Over 75% of the carbon and nitrogen assimilation was in the <5 mu m fraction at the south of the transect; this decreased to approximately 10% in the upwelling region. New production (f ratios) varied between approximately 0.1 in the oligotrophic regions and 0.9 in the upwelling region.
AN: 3567037
610 of 1521
TI: Productivity regime and phytoplankton size structure in the Arabian Sea
AU: Jochem,-F.J.; Pollehne,-F.; Zeitzschel,-B.
AF: Inst. Meereskd. Univ. Kiel, Duesternbrooker Weg 20, 2300 Kiel, FRG
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 711-735
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The productivity regime and size structure of phytoplankton are described for three different epipelagic systems in the Arabian Sea during the inter-monsoon period in spring 1987: (1) the coast of Oman; (2) the central Arabian Sea; and (3) the shelf off Pakistan. These results are related to the functioning of the specific ecosystem. Off the coast of Oman, the transition from a surface maximum of autotrophic biomass and production to a more oligotrophic system, with a chlorophyll subsurface maximum, was observed. Concomitantly, the size spectrum changed towards a higher significance of picoplankton. In the central Arabian Sea, a typical oligotrophic system with a pronounced subsurface maximum of autotrophic biomass and primary production was encountered. Here, the epipelagic system could be divided into two distinct sub-systems: the surface layer "regenerated" production, the predominance of picophytoplankton and minor losses due to sedimentation, thus a "closed" system; and the subsurface maximum layer at the nutricline characterized by higher sedimentation losses and more diatoms. Both sub-systems showed about the same productivity, the turnover in the surface layer having been much greater than in the subsurface maximum. The system on the shelf off Pakistan is seen as a decay stage of the open ocean system when water from offshore is transported onto the shelf during the onset of monsoon winds.
AN: 3567036
611 of 1521
TI: Low light adaptation and export production in the deep chlorophyll maximum layer in the northern Indian Ocean
AU: Pollehne,-F.; Klein,-B.; Zeitzschel,-B.
AF: Inst. Ostseeforsch., Seest. 15, O-2530 Rostock-Warnemunde, FRG
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 737-752
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Phytoplankton standing stock and primary production rates were measured in the central northern Indian Ocean at 65 degree E and 18 degree N in the inter-monsoon period in May 1987. As the algal populations were dominated by minute forms difficult to assess by routine microscopic methods, main algal groups were identified by pigment patterns derived from HPLC-analysis. The main ecological significance of the deep chlorophyll maximum layer at that time was its role as a source of export production while importing "new" nutrients from below the nitracline. HPLC and elemental analyses of sediment trap material proved this layer to be the source of most of the sedimenting particles. Calculations of nitrogen fluxes suggested the import and export terms to be well balanced.
AN: 3567035
612 of 1521
TI: Bacterioplankton distributions and production in the northwestern Indian Ocean and Gulf of Oman, September 1986
AU: Ducklow,-H.W.
AF: Horn Point Environ. Lab., Univ. Maryland CEES, Box 775, Cambridge, MD 21613, USA
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 753-771
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Bacterial abundance and super(3)H-thymidine incorporation were measured throughout the water column during September-October 1986, along transects in the north western Arabian Sea and Gulf of Oman. Bacterial abundances and production estimated from incorporation rates were high (>1 x 10 super(9) cells/l and 30-92% of primary production, respectively) along the oceanic portions of the transects. These elevated levels may indicate a response to the decline of summer phytoplankton blooms stimulated by monsoonal deepen of the mixed layer. Bacterial production and abundance profiles had complex vertical structure with multiple subsurface maxima related to chlorophyll and oxygen distributions. Production and abundance both declined exponentially with depth below 100-200 m. Rates of dissolved organic carbon (DOC) release from the sinking particle flux may have been adequate to support bacterial production in the Gulf of Oman, but in the open Arabian Sea this source appeared to be insufficient to meet the bacterial demand. The bacterial production estimates reported herein are very conservative because very low conversion factors were used. In general these results suggest that the carbon sources usually assumed to support bacterial production (e.g., phytoplankton exudation, particle breakdown) supply only a fraction of the bacterial demand in the northwest Indian Ocean.
AN: 3567033
613 of 1521
TI: Synechococcus and its importance to the microbial foodweb of the northwestern Indian Ocean
AU: Burkill,-P.H.; Leakey,-R.J.G.; Owens,-N.J.P.; Mantoura,-R.F.C.
AF: Plymouth Mar. Lab., Prospect Pl., The Hoe, Plymouth PL1 3DH, UK
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 773-782
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The abundance, distribution, size, biomass, growth and grazing-induced mortality of phycoerythrin (PE) rich chrococcoid cyanobacteria were studied during September-October 1986 in the Arabian Sea, the Gulf of Oman and the monsoonal upwelling region off the South East Arabian coast. Cyanobacteria were abundant through the region and particularly so in oligotrophic waters where they exhibited distinct subsurface concentration maxima that were situated above, but related to the depth of the chlorophyll maxima. Cell diameter increased from 0.7 mu m in surface waters to 1.2 mu m at depth. Standing stocks of cyanobacteria ranged up to 50 mu gC/l, and accounted for up to 40% of the POC in oligotrophic stations indicating that Synechococcus constitutes an important trophic resource. Experimental investigations showed that cyanobacterial populations were growing fast, with specific growth rates of 0.5-1.0/day, while simultaneously experiencing high mortality due to microzooplankton grazing. Grazing rates varied between 0.3 and 1.2/day, indicating that 31-71% of the cyanobacteria were predated daily. Grazing and cyanobacterial growth were correlated, suggesting that Synechococcus production and its fate by microbial grazing activity were tightly coupled. Cyanobacteria are clearly a major component of a dynamic but well-balanced microbial foodweb present in oligotrophic regions of the northwest Indian Ocean.
AN: 3567032
614 of 1521
TI: Effects of forest management on biogeochemical functions in southern forested wetlands
AU: Walbridge,-M.R.; Lockaby,-B.G.
AF: Dep. Biol., George Mason Univ., Fairfax, VA 22030-4444, USA
SO: WETLANDS 1994 vol. 14, no. 1, pp. 10-17
LA: English
ER: F (Freshwater)
AB: Southern forested wetlands perform two important biogeochemical functions on the landscape: 1) nutrient (N and P) removal from incident surface, subsurface, and ground waters, and 2) export of organic carbon and associated nutrients to aquatic ecosystems downstream. In addition to P sediment deposition, which can range from 1.6 to 36.0 kg/ha/yr P, denitrification of NO sub(3)-N (0.5 to 350 kg/ha/yr) and P adsorption (130 to 199 kg/ha/yr) can be important mechanisms associated with N and P removal, respectively. Biological processes, uptake by plants (15.0 to 51.8 kg/ha/yr for N; 0.2 to 3.8 kg/ha/yr for P) and microorganism absorption (16.2 to 87.0 kg/ha/yr for N; 6.6 to 40.0 kg/ha/yr for P) are also important and are intimately associated with organic matter export. Clearcut harvests (ground-based or aerial), followed by natural regeneration, are the most common silvicultural techniques used in forested floodplains in the South. Ground-based methods have been shown to increase soil bulk density and decrease hydraulic conductivity and redox potential in wetter soils. In addition to the increases in soil temperature and soil wetness that frequently occur following forest harvesting, these added effects may be responsible for the reduced productivity and altered species composition observed following ground-based vs. aerial harvests. Changes in denitrification will be a function of the degree to which harvesting affects soil redox potential, substrate (C) availability, and nitrate production. In theory, denitrification rates should increase following harvesting, but low nitrate availability in acid soils may limit this effect. The effects of harvesting on P adsorption processes in forested wetland soils have not been studied. Reductions in plant uptake and litterfall and changes in species composition following harvesting could alter both nutrient retention/transformation and organic C export functions. On wetter sites, canopy removal may stimulate algal populations, providing a short-term mechanism for conserving geochemical exports. Clearcut harvest systems that minimize alterations in soil hydrology and promote rapid vegetation regrowth should have the least effect on biogeochemical functions in southern forested wetlands.
AN: 3565930
615 of 1521
TI: Effect of the genus Mnemiopsis ctenophore, a recent Black Sea immigrant, on the hydrolytic enzymatic processes of protein and polysaccharide decomposition in sea water.
OT: Vliyanie grebnevika Mnemiopsis - vselentsa Chernogo morya na gidroliticheskie fermentativnye protsessa rasshchepleniya belkov i polisakharidov v morskoj vode
AU: Korneeva,-G.A.; Vedernikov,-V.I.
AF: Inst. Okeanol. RAN, Moscow, Russia
SO: IZV.-RAN-BIOL.-PROC.-ACAD.-SCI.-BIOL. 1994 no. 1, pp. 127-131
LA: Russian
ER: M (Marine)
AB: For the first time it was found experimentally that the hydrolytic enzymatic activities in sea water increased in the presence of the ctenophore. Analysis of the experimental results suggests that the Mnemiopsis ctenophore is an important factor activating the biochemical transformation of organic matter in the aerobic zone of the Black Sea.
AN: 3565638
616 of 1521
TI: Factors affecting respiration in dry pond bottom soils
AU: Boyd,-C.E.; Pippopinyo,-S.
AF: Dep. Fish. and Allied Aquacult., Alabama Agric. Exp. Stn., Auburn Univ., Auburn, AL 36849, USA
SO: AQUACULTURE 1994 vol. 120, no. 3-4, pp. 283-293
LA: English
ER: B (Brackish); F (Freshwater)
AB: The potential influence of drying, liming, tilling, bacterial augmentation, and nitrogen fertilization on respiration of pond bottom soil exposed to air between crops was evaluated in laboratory studies using soil respiration chambers. The optimum soil moisture concentration for respiration was 12-20%, and further drying decreased soil respiration. Soil respiration was greatest at pH 7.5-8.0, and both calcium hydroxide and calcium carbonate were effective in enhancing respiration of acidic soil. Pulverization of soil to eliminate the hard surface crust formed on drying accelerated respiration, thus tilling of pond bottom soils would be expected to increase respiration. Nitrogen fertilization showed some benefit to soil respiration, but there was no value in bacterial augmentation. These laboratory findings provide background information useful to pond studies on bottom soil treatments.
AN: 3564640
617 of 1521
TI: Biodegradation of sucralose, a chlorinated carbohydrate, in samples of natural environments
AU: Labare,-M.P.; Alexander,-M.*
AF: Lab. Soil Microbiol., Dep. Soil, Crop and Atmos. Sci., Cornell Univ., Ithaca, NY 14853, USA
SO: ENVIRON.-TOXICOL.-CHEM. 1993 vol. 12, no. 5, pp. 797-804
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Measurements were made of the biodegradation of 4-chloro-4-deoxy- alpha ,D-galactopyranosyl-1,6-dichloro-1,6- dideoxy- beta ,D-fructofuranoside (sucralose) in samples of several natural environments. This chlorinated carbohydrate, which represents a new class of artificial sweeteners, was extensively transformed to CO sub(2) in four mineral soils with pH values of 4.9 to 7.2. Mineralization occurred at concentrations of 0.01 to 1,000 mg of sucralose per kilogram of soil, and the initial rates were a direct function of substrate concentration. At the lower concentrations, mineralization was initiated with no detectable acclimation period. Mineralization was not evident in soil under anaerobiosis. Mineralization occurred in lake sediments, sewage, and estuarine water but at lower rates and lesser extents than in soils. Little mineralization was evident in samples from oligotrophic, mesotrophic, and eutrophic lakes, the extent of mineralization being often less than the contamination level of the sucralose preparation. Sucralose degradation resulted from microbial activity because mineralization did not occur in sterilized environmental samples, and the addition of cycloheximide or streptomycin to soil significantly reduced mineralization. No bacterium could be isolated that was capable of utilizing sucralose as the sole carbon source. The data suggest that the biodegradation of sucralose is a cometabolic process.
AN: 3560978
618 of 1521
TI: Isotopic signatures ( super(14)C, super(13)C, super(15)N) as tracers of sources and cycling of soluble and particulate organic matter in the Santa Monica Basin, California
AU: Williams,-P.M.; Robertson,-K.J.; Soutar,-A.; Griffin,-S.M.; Druffel,-E.R.M.
AF: Scripps Inst. Oceanogr., Univ. California, San Diego, La Jolla, CA 92093, USA
SO: PROG.-OCEANOGR. 1992 vol. 30, no. 1-4, pp. 254-290
LA: English
ER: M (Marine)
AB: Measurements of Delta super(14)C, delta super(13)C and delta super(15)N are reported for dissolved (plus colloidal), suspended and sinking particulate, and total sedimentary organic matter in the Santa Monica Basin (mid-basin and shelf sites) on CaBS cruises 1, 3, 4, 7, 8 and 10. These isotopic signatures were indicative of the following processes occurring within the basin regime: terrestrial inputs of organic matter to the sinking and suspended particulate organic matter were of the order of 10% or less, and as high as 25% for the sedimentary organic matter; Delta super(14)C values of the UV-oxidizable dissolved organic matter below 5 m were similar to those measured in open ocean waters, while the Delta super(14)C values in the suspended, and, to a lesser degree, in the sinking organic matter decreased markedly with depth. This latter decrease was primarily attributed to episodic resuspension of shelf and slope sedimentary organic matter, and secondarily to natural and/or anthropogenic petroleum inputs; and the isotopic signatures of the UV-oxidizable dissolved organic matter, coupled with total dissolved carbon and amino acid and carbohydrate concentrations were strikingly similar in the deep basin and at an open-ocean site, suggesting a common history for the subsurface (>300 m) and deep water at both sites. In addition, total mass and organic carbon and nitrogen fluxes from five particle trap deployments are described in detail. Mass fluxes increased with depth, especially on the shelf, suggesting that particle input from the basin slopes may reach the mid-basin site. We conclude that there is minimal perturbation of all organic phases in the basin from terrestrial sources, and that the properties of the UV-oxidizable dissolved organic matter are not greatly influenced by particles of local origin.
AN: 3559040
619 of 1521
TI: Upper ocean mixing: The use of algal pigments as biological tracers for turbulent diffusion
AU: Welschmeyer,-N.
CA: Moss Landing Marine Labs., CA (USA)
SO: 1992 4 pp
LA: English
ER: M (Marine)
AB: The goal of the proposed research was to develop an in situ method for determining upper-ocean mixing rates using algal pigments as natural biological tracers. The work focused specifically on xanthophyll-cycling, a well known series of reversible, light-sensitive pigment transformations that occur in all higher land plants and many marine phytoplankton species. Laboratory work was initiated to define the rate constants for xanthophyll-cycling in microalgal cultures, and to develop a quantitative understanding of the influence of light intensity on the xanthophyll-cycling process. Field work was completed which verified that xanthophyll-cycling processes measured in natural phytoplankton populations indeed reproduced our laboratory observations. A Monte-Carlo computer model was developed in order to study the influence of xanthophyll-cycling on algal pigmentation under known conditions of simulated mixing. The collective results from physiological experimentation and simulation modeling were used to develop a field method for calculating ocean mixing rates (Welschmeyer and Hoepffner, 1991; Welschmeyer 1991). The work has now identified previously unrecognized relationships between xanthophyll- cycling and cellular fluorescence, which are of potential importance in exploiting single-cell characteristics as novel tracers of ocean mixing. This new work is continuing in our laboratory.
AN: 3557678
620 of 1521
TI: Biogeochemical interactions in the Equatorial Pacific
AU: Barber,-R.T.; Murray,-J.W.,Jr.; McCarthy,-J.J.
AF: Duke Univ., Sch. Environ., Mar. Lab., 111 Pivers Island Rd., Beaufort, NC 28516-9721, USA
SO: AMBIO 1994 vol. 23, no. 1, pp. 62-66
LA: English
ER: M (Marine)
AB: During 1992, the Joint Global ocean Flux Study (JGOFS) investigated biogeochemical fluxes in the central equatorial Pacific Ocean. The equatorial pacific is the largest natural source of atmospheric carbon dioxide, but the magnitude of the flux varies interannually with the El Nino-Southern Oscillation cycle. Sediments beneath the equatorial upwelling are enriched in organic carbon indicating a strong export flux, but contemporary new primary production is lower than expected given the relative concentrations of new nutrients. The multidisciplinary JGOFS research plan was designed to address apparent contradictions in this system, and to assess the roles of equatorial physical and biological processes in regulating the ocean-atmosphere exchange of carbon.
AN: 3557067
621 of 1521
TI: Nitrogen-15 and oxygen-18 characteristics of nitrous oxide: A global perspective
AU: Kim,-K.-R.; Craig,-H.
AF: Isotope Lab., Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093-0220, USA
SO: SCIENCE-WASH. 1993 vol. 262, no. 5141, pp. 1855-1857
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The global budget of N sub(2)O shows a significant imbalance between the known rate of destruction in the stratosphere and the estimated rates of natural and anthropogenic production in soils and the ocean. Measurements of the super(15)N/ super(14)N and super(18)O/ super(16)O ratios in two major tropospheric sources of N sub(2)O, tropical rain forest soils and fertilized soils, show that soil N sub(2)O from a tropical rain forest in Costa Rica and from sugar-cane fields in Maui is strongly depleted in both super(15)N and super(18)O relative to mean tropospheric N sub(2)O. A major source of heavy N sub(2)O, enriched in both super(15)N and super(18)O, must therefore be present to balance the light N sub(2)O from soils. One such source is the back-mixing flux of N sub(2)O from the stratosphere, which is enriched in super(15)N and super(18)O by photolysis and chemistry. However these return fluxes of super(15)N and super(18)O are so great that a large oceanic flux of N sub(2)O is required to balance the heavy isotope-enriched stratospheric flux. All these effects will be reflected in climatically related isotopic variations in trapped N sub(2)O in polar ice cores.
AN: 3556321
622 of 1521
TI: Global nitrogen cycle within the coupled C-N-P system
AU: Lerman,-A.; MacKenzie,-F.T.; Ver,-L.M.
AF: Dep. Geol. Sci., Northwestern Univ., Evanston, IL 60208, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 389-392
LA: English
ER: M (Marine)
AB: The system of C-N-P coupled biogeochemical cycles represents the main interactions between the biosphere and the inorganic world of the planetary surface environment. Within this system, nitrogen occupies a unique position owing to its overwhelmingly large atmospheric reservoir that exceeds by large factors its other major environmental reservoirs, such as the land phytomass, the oceans, and sediments. Our recent version of the global biogeochemical cycle of nitrogen emphasizes three major divisions of the environment: the land part, the coastal margins, and the open oceans. The reservoir masses and the values of some of the more important fluxes are summarized. Features of the nitrogen cycle which are particularly relevant to an understanding of the changing picture of the present-day cycle are discussed.
AN: 3555300
623 of 1521
TI: Sediment-nutrient interactions in tropical seagrass beds: A comparison between a terrigenous and a carbonate sedimentary environment in South Sulawesi (Indonesia)
AU: Erftemeijer,-P.L.A.; Middelburg,-J.J.
AF: Netherlands Inst. Ecol., Cent. Estuar. and Coast. Ecol., Vierst. 28, 4401 EA Yerseke, Netherlands
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 102, no. 1-2, pp. 187-198
LA: English
ER: M (Marine)
AB: The relationship between porewater nutrient concentrations and sediment characteristics was studied in seagrass beds on 2 sediment types in South Sulawesi, Indonesia. Porewater nutrient concentration gradients with sediment depth and ratios between ammonium and phosphate porewater concentrations in a terrigenous muddy sedimentary environment could be explained by modelling based on stoichiometric decomposition of organic material and molecular diffusion. Measured pore-water phosphate concentrations in a carbonate sedimentary environment, however, were significantly higher (10 mu M excess) in the upper few cm of the sediment than would be expected based on stoichiometry. This apparent phosphate enrichment is attributed to rapid regeneration of both N and P in the rhizosphere and subsequent rapid removal of ammonium by nitrification. Sampling artefacts and additional geochemical sources of dissolved P (reduction of hydrous ferric oxides, calcium carbonate dissolution) could be excluded as the cause of the enrichment.
AN: 3554567
624 of 1521
TI: Mineralization of organic nitrogen and carbon (fish food) added to anoxic sediment microcosms: Role of sulphate reduction
AU: Hansen,-L.S.; Holmer,-M.; Blackburn,-T.H.
AF: Dep. Microbial. Ecol., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C., Denmark
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 102, no. 1-2, pp. 199-204
LA: English
ER: M (Marine)
AB: Substrate (fish food) was added to gas-tight bags containing sediment, with and without molybdate. Amino-nitrogen (amino-N) was measured by high-performance liquid chromatography. The oxidation of 3 representative super(14)C-labelled amino acids (glutamic acid, alanine and arginine) was measured and the mean decay rate constant was used to calculate turnover rates of amino-N. Concentrations of dissolved organic nitrogen, dissolved organic carbon, total organic carbon and ammonium were measured during 28 d of incubation. Inhibition of sulphate-reducing activity gave a 4.2-fold decrease in the rate of ammonium reduction and a 4.5-fold decrease in the rate of amino acid turnover. These results suggest an active participation of sulphate-reducing bacteria in amino acid oxidation.
AN: 3554560
625 of 1521
TI: Multiphasic kinetics can be an artifact of the assumption of saturable kinetics for microorganisms
AU: Logan,-B.E.; Fleury,-R.C.
AF: Dep. Chem. and Environ. Eng., Univ. Arizona, Tucson, AZ 85721, USA
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 102, no. 1-2, pp. 115-124
LA: English
ER: M (Marine)
AB: Much of the evidence for the application of Michaelis-Menten kinetics to bacterial suspensions is derived from Wright-Hobbie plots of radionuclide uptake and incorporation rates in the presence of naturally occurring concentrations of substrates. It is shown that the same data used to support saturation models can also be fitted by a diffusion-based transport equation. Mixed, pure and natural assemblages of microorganisms were used to study glucose uptake and thymidine and leucine incorporation. Multiphasic kinetics for glucose uptake by mixed cultures was observed when data were plotted on a Wright-Hobbie plot (K+S values of 2.7, 37 and 3500 mu M), but the diffusion model fit data with a single set of coefficients over a 6 orders of magnitude range in glucose concentrations. It is suggested that diffusive transport into the cell is dominant at the relatively high thymidine and leucine concentrations used in bacterial production studies, and that non-saturable diffusive transport contributes to widely varying bacterial conversion factors.
AN: 3554476
626 of 1521
TI: Reactivity of aquatic iron(III) oxyhydroxides -- implications for redox cycling of iron in natural waters
AU: Deng,-Yiwei; Stumm,-W.
AF: Dep. Inorg. Chem., R. Inst. Technol., 10044 Stockholm, Sweden
SO: APPL.-GEOCHEM. 1994 vol. 9, no. 1, pp. 23-36
LA: English
AB: The reactivity of iron(III) oxyhydroxides as reflected by their tendency to dissolve is of great importance in the redox cycling of iron and the bioavailability of iron to phytoplankton in natural waters. In this study, various iron(III) oxyhydroxides were produced by oxygenation of iron(II) in the presence of solutes, such as phosphate, sulfate, bicarbonate, valeric acid, TRIS, humic and fulvic acids, and in the presence of minerals, such as bentonite and delta -Al sub(2)O sub(3) under conditions encountered in aquatic systems. The reactivity of the different iron(III) oxyhydroxides was subsequently assessed by means of a reductive dissolution using ascorbate and non-reductive dissolution using HQS (8-hydroxyquinoline-5-sulfonic acid) or oxalate. The experimental results show that the iron(III) oxyhydroxides with a low degree of polymerization exhibit higher reactivity than those with a high degree of polymerization or with high crystallinity. The quantity of active surface sites and the coordination arrangement of the functional groups at the surface of the iron(III) oxyhydroxides, especially the extent of the endstanding -OH groups per iron(III) ion determine the reactivity of iron(III) oxyhydroxides toward dissolution. Surfaces, such as clay and aluminum oxides, not only accelerate the oxygenation reaction of iron(II), but also induce the formation of iron(III) oxyhydroxides which are more active toward the dissolution reactions. Polymerization of iron(III) oxyhydroxides on the surfaces occurs predominantly in two dimensions rather than in three dimensions. In a laboratory experiment, the iron(III) oxyhydroxide formed in the presence of TRIS can be reduced by fulvic acid in a closed system under the following conditions: Fe(OH) sub(3)(s) 0.01 g/l, fulvic acid 5 mg/l, pH 7.5, 20 degree C. The kinetics of the reaction depend on the reactivity of iron(III) oxyhydroxide and reducing power of fulvic acid. Although reductants other than fulvic acid may be of importance in natural waters, this result provides the laboratory evidence that the >Fe super(III)-OH/Fe(II) is able to act as an electron transfer mediator for the oxidation of natural organic substances, such as fulvic acid, by molecular oxygen either in the absence of microorganisms or as a supplement to microbial activity.
AN: 3553684
627 of 1521
TI: Sulfate reduction and thiosulfate transformations in a cyanobacterial mat during a diel oxygen cycle
AU: Joergensen,-B.B.
AF: Max Planck Inst. Mar. Microbiol., Fahrenheitstr. 1, D-28359 Bremen, FRG
SO: FEMS-MICROBIOL.-ECOL. 1994 vol. 13, no. 4, pp. 303-312
LA: English
ER: M (Marine); B (Brackish)
AB: Bacterial sulfate reduction and transformations of thiosulfate were studied with radiotracers in a Microcoleus chthonoplastes-dominated microbial mat growing in a hypersaline pond at the Red Sea. The study showed how a diel cycle of oxygen evolution affected respiration by sulfate-reducing bacteria and the metabolism of thiosulfate through oxidative and reductive pathways. Sulfate reduction occurred in both oxic and anoxic layers of the mat and varied diurnally, apparently according to temperature rather than to oxygen. Time course experiments showed that the radiotracer method underestimated sulfate reduction in the oxic zone due to rapid reoxidation of the produced sulfide. Extremely high reduction rates of up to 10 mu mol cm super(-3)/d were measured just below the euphotic zone. Although thiosulfate was simultaneously oxidized, reduced and disproportionated by bacteria in all layers of the mat, there was a shift from predominant oxidation in the oxic zone to predominant reduction below. Concurrent disproportionation of thiosulfate to sulfate and sulfide occurred in all zones and was an important pathway of the sulfur cycle in the mat.
AN: 3553681
628 of 1521
TI: Microbial mats in the hypersaline ponds of Mediterranean salterns (Salins-de-Giraud, France)
AU: Caumette,-P.; Matheron,-R.; Raymond,-N.; Relexans,-J.-C.
AF: Lab. Oceanogr. Biol., Univ. Bordeaux I, 2 rue Pr. Jolyet, 33120 Arcachon, France
SO: FEMS-MICROBIOL.-ECOL. 1994 vol. 13, no. 4, pp. 273-286
LA: English
ER: M (Marine); B (Brackish)
AB: Microbial mats that develop in the gypsum crust of the hypersaline ponds of Salins-de-Giraud (Camargue, France) were carefully investigated between 1989 and 1991. During the warm seasons, when these mats were fully developed, analyses of microbial activities and microprofiles of oxygen and sulfide have shown a great activity of the different kinds of bacteria found in the mat below the gypsum crust. Oxygen production could amount to 2 mu mol cm super(-3)/h during the maximum daylight whereas the oxidation of sulfide in the light was calculated to be 12.7 mu mol cm super(-3)/h, i.e. 300 to 180 mmol m super(-2)/day assuming 8-10 hours of constant daylight and a sulfide oxidation zone of 3 mm in thickness. This sulfide oxidation consumes about 65-95% of the diel sulfide production which has been estimated to be 400 to 450 mmol m super(-2)/day originating from sulfate reduction which takes place in the 6 cm depth horizon of sediment plus mat. According to the amounts of sulfate precipitated at the sediment surface in the form of gypsum, sulfate reduction is never limited and was found to be among the highest values reported in the literature (average value of 8200 nmols cm super(-3)/day). Completely covered by the gypsum crust, this ecosystem has been found to react as a closed system. Consequently, the sulfide does not escape and accumulate below the crust. It was detected up to the top of the mat after a few hours of darkness. It is reoxidized during the day by the photosynthetic organisms that form the mats. These latter mats were composed of 2 to 3 laminated layers of phototrophic organisms: an upper brown layer of the cyanobacterium Aphanothece an intermediate green layer of the cyanobacterium Phormidium and an underlying red layer of purple sulfur-oxidizing bacteria from which two new halophilic species were isolated (Chromatium salexigens and Thiocapsa halophila). It has been found that the accumulated sulfide is oxidized not only by the phototrophic bacteria in the sulfide oxidation zone but also by the oxygen produced by the cyanobacteria which are able to photosynthesize in the presence of sulfide.
AN: 3553680
629 of 1521
TI: Biological sinks for nitrogen additions to a forested catchment
AU: Nadelhoffer,-K.J.; Aber,-J.D.; Downs,-M.R.; Fry,-B.; Melillo,-J.M.
CA: Marine Biological Lab., Woods Hole, MA (USA). Ecosystems Cent.
CO: Int. Symp. of Experimental Manipulations of Biota and Biogeochemical Cycling in Ecosystems, Copenhagen (Denmark), May 1992
SO: ECOL.-RES.-SER.-U.S.-ENVIRON.-PROT.-AGENCY 1992 9 pp
RN: EPA/600/A-92/292 (EPA600A92292)
LA: English
ER: F (Freshwater)
AB: The goal of this research is to identify and quantify sinks for experimental Nitrogen (N) additions to a forested catchment at the Bear Brooks Watershed in Maine (BBWM) where background N deposition rates are low (< 4 kg/ha/yr). Nitrogen applied to the watershed in April, June, August and October (16.8 kg/ha) 1991 was labeled with a (15)N tracer that increased the abundance of (15)N label from about 0.3663 atm % to 0.4366 atm %. Surface soil was the most important sink for the isotopically labelled N additions. We estimate using (15)N mass balancing that about 3/4 of the 16.8 kg N added during the 1991 growing season was retained in catchment soil and aboveground vegetation with soils being the dominant sink.
AN: 3551716
630 of 1521
TI: Phosphorus dynamics in the Amazon River and estuary
AU: Rao,-Ji-Long; Berner,-R.A.
AF: Dep. Geol. and Geophys. Yale Univ., New Haven, CT 06511, USA
SO: CHEM.-GEOL. 1993 vol. 107, no. 3-4, pp. 397-400
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: It has been revealed that rivers are the dominant channel for passing phosphorus into the ocean from the continents and that estuaries provide an important control on the exogenic cycle of phosphorus. However, the amount of phosphorus available for dissolutive transfer in bio-geochemical cycles is usually only a small fraction of the total-P in sediments, and there is no simple relationship between the amount of the transferable phosphorus and of the total phosphorus. Therefore, the determination of different forms of phosphorus in sediments becomes a critical step in order to get a reasonable global budget calculation for phosphorus and to understand the behavior of phosphorus in the exogenic cycle. In order to identify and quantify the different forms of phosphorus in sediment, a modified selective extraction technique has been developed which provides an optimized procedure with high precision. By means of the procedure, separate solid forms of phosphorus have been distinguished in marine and fluvial sediments from a number of Amazon locations.
AN: 3550673
631 of 1521
TI: Seasonal fluctuation of export and recycled production in different subareas of the Southern Ocean
AU: Goeyens,-L.; Dehairs,-F.
AF: Vrije Univ. Brussel, Pleinlaan, 2, B-1050 Brussels, Belgium
SO: BELGIAN-SCIENTIFIC-RESEARCH-PROGRAMME-ON-THE-ANTARCTIC.-SCIENTIFIC-RESULTS-OF-PHASE-TWO-10-1988-01-1992.-VOLUME-1.-PLANKTON-ECOLOGY-AND-MARINE-BIOGEOCHEMISTRY. Caschetto,-S.-ed. BRUSSELS-BELGIUM BELGIAN-SCIENCE-POLICY-OFFICE 1993 pp. 1-79
ST: BELG.-SCI.-RES.-PROG.-ANTARCT.
LA: English
ER: M (Marine)
AB: As the role of the Southern Ocean in the global biogeochemical carbon cycle is nowadays a leading concern in oceanographic research, this study emphasizes the specific effects of nitrogenous nutrients on the origin, development and fate of primary production. The inherent consequences of nitrogen utilization by phytoplankton for the channelling of organic nitrogen towards in-situ regeneration or towards sedimentation are investigated. The results obtained during different Antarctic cruises provides clear evidence for a distinction between different Antarctic ecosystems. Intensive new production, characteristic for fertile zones bordering the retreating ice edge was mainly conveyed towards the regenerating microbial network. This was mirrorred by enhanced ammonium availability and poor subsurface barite accumulation. On the other hand, the moderate to low primary production of open sea and close pack ice zones was available for export and only small amounts of the organic matter were remineralized in the upper layer. Additionally, we propose a scaling function, based on the correlation between barite concentrations in the subsurface Ba-maximum layer and oxygen concentrations in the O sub(2)-minimum layer observed for the Indian Ocean's sector. The equation provides a tool to estimate export of organic matter at any other Southern Ocean site starting with information on net barite accumulations over the season.
AN: 3550544
632 of 1521
TI: Coastal metabolism and the oceanic organic carbon balance
AU: Smith,-S.V.; Hollibaugh,-J.T.
AF: Dep. Oceanogr., Univ. Hawaii, Honolulu, HI 96822, USA
SO: REV.-GEOPHYS. 1993 vol. 31, no. 1, pp. 75-89
LA: English
ER: M (Marine)
AN: 3549939
633 of 1521
TI: Perception and selection of macrophyte detrital falls by the bathyal echinoid Stylocidaris lineata
AU: Young,-C.M.; Tyler,-P.A.; Emson,-R.H.; Gage,-J.D.
AF: Harbor Branch Oceanogr. Inst., 5600 Old Dixie Highw., Fort Pierce, FL 34946, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 7, pp. 1475-1486
LA: English
ER: M (Marine)
AB: Many deep-sea animals are known to exploit patchy food resources such as animal carcasses and sunken plant remains, but the mechanisms by which such foods are located remain generally unknown. The bathyal echinoid Stylocidaris lineata is an omnivorous deposit feeder that ingests sediment, dead animal remains, seagrass blades, and macroalgae such as Sargassum spp. Using a submersible, we investigated the ability of urchins to locate and exploit large falls of detritus. Individuals quickly arrived at packets of Thalassia testudinum and Sargassum spp. placed on the bottom, and they preferred these food items significantly over inert controls. However, the echinoids demonstrated no significant tendency to move toward the scent of upstream T. testudinum, either in situ or in laboratory flume experiments. Individuals moved at net speeds up to 30 m/day. The existing evidence suggests that S. lineata locate food by chance encounter, not distant chemoreception.
AN: 3548537
634 of 1521
TI: Dimethylsulphide and dimethylsulphoniopropionate in the Northeast Atlantic during the summer coccolithophore bloom
AU: Malin,-G.; Turner,-S.; Liss,-P.; Holligan,-P.; Harbour,-D.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 7, pp. 1487-1508
LA: English
ER: M (Marine)
AB: Concentrations of dimethylsulphide (DMS) and dissolved and particulate pools of its precursor, dimethylsulphoniopropionate (DMSP), were surveyed at the time of the summer bloom of coccolithophores in the Northeast Atlantic. The average DMS concentration was 12 nmol dm super(-3) (n = 158, range 1.06-93.8 nmol dm super(-3), sigma n - 1 = 12.4). Statistically significant positive correlations between particulate DMSP and chlorophyll were found for samples from areas where coccolithophores accounted for 50% or more of the total carbon biomass. In these areas correlations between DMS and chlorophyll were not as strong but still significant. An estimate of the flux of DMS from the Northeast Atlantic in June-July (721 nmol m super(-2)/h) is of the same order as estimates for the southern North Sea at the same time of year (646 nmol m super(-2)/h). The data provide strong evidence for the importance of coccolithophores in the emission of DMS to the atmosphere. Comparison of flux data with budgets for airborne sulphur in Europe, reported by the European Monitoring and Evaluation Programme (EMEP), suggests that in summer the Northeast Atlantic may be a source of the sulphur deposited on adjacent land areas not strongly affected by anthropogenic sulphur sources. The overall results are discussed in relation to present knowledge of the global distribution of coccolithophores.
AN: 3547251
635 of 1521
TI: Radionuclide concentrations, fluxes, and residence times at Santa Monica and San Pedro Basins
AU: Wong,-Kai-M.; Jokela,-T.A.; Eagle,-R.J.; Brunk,-J.L.; Noshkin,-V.E.
AF: Environ. Sci. Div., Univ. California, Lawrence Livermore Natl. Lab., Livermore, CA 94550, USA
SO: PROG.-OCEANOGR. 1992 vol. 30, no. 1-4, pp. 353-357
LA: English
ER: M (Marine)
AB: Our participation in the California Basin Study (CaBS) in 1986-1988 has produced a radionuclide data base that allows us to trace the particle and water movement in the Santa Monica and the San Pedro Basins. These data enable us to calculate the radionuclide inventories in the three compartments of the basin, the water column, the settling particles, and the sediments. We have also determined the fluxes of several radionuclides associated with the sinking particles, the residence time in the water column, and the rate of deposition in the sediments. The biogeochemical environment of the Santa Monica Basin is uniquely suited to the application of tracer techniques to study the sedimentation processes. Subtle, but measurable changes in the distribution of fallout of super(137)Cs from 1977 to 1988 were noted in the water column. Compared to the decay corrected measurement in 1973-1977 at the Geosecs and Farallon Islands stations off the coast of California, super(137)Cs inventory in the water column in Santa Monica Basin has not changed significantly for the past decade. Increases in the deep water concentration profiles of super(137)Cs partially resulted from particle transport and diagenetic release of cesium in the deep water. The major super(137)Cs inventory (> 70%) resides in the upper 400m of water, with a mean residence time of 480 plus or minus 90 years. Less than 11% of the total super(137)Cs inventory was found in the sediments at water depths of 900m in 1987. Unlike super(137)Cs, more than 80% of the fallout super(239+240)Pu has been deposited in the Santa Monica Basin sediments. A mean residence time of 13 plus or minus 12 years was measured for super(239+240)Pu in the basin water. The ubiquitous super(239+240)Pu subsurface concentration maximum observed in the Pacific oceanic waters at about 350m depth is also evident in the basin water. We have no definitive explanation for the persistence of the subsurface maximum except that it appears to be correlated with the density gradient at 26.5 to 26.9 sigma-t.
AN: 3546899
636 of 1521
TI: Post-mortem formation of inorganic arsenic from arsenobetaine in a shark under natural conditions
AU: Hanaoka,-K.; Kogure,-T.; Miura,-Y.; Tagawa,-S.; Kaise,-T.
AF: Dep. Food Sci. and Technol., Shimonseki Univ. Fish., Nagata-honmachi 2-7-1, Shimonoseki 759-65, Japan
SO: CHEMOSPHERE 1993 vol. 27, no. 11, pp. 2163-2167
LA: English
ER: M (Marine)
AB: The ubiquity of an organic arsenic compound, arsenobetaine [(CH sub(3)) sub(3)As super(+)CH sub(2)COO super(-)], in marine animals is wellknown. On the other hand, the fate of it is not well known in vivo. The degradation of arsenobetaine accumulated in a shark to inorganic arsenic was shown to occur in a natural environment. This means that arsenobetaine bioconverted from inorganic arsenic from sea-water is degraded to original inorganic arsenic.
AN: 3545368
637 of 1521
TI: Studies of iron bacteria from a mangrove ecosystem in Goa and Konkan
AU: Panchanadikar,-V.V.
AF: Reg. Res. Lab., Bhubaneswar-751013, India
SO: INT.-J.-ENVIRON.-STUD.,-SECT.-A 1993 vol. 45, no. 1, pp. 17-21
LA: English
ER: B (Brackish)
AB: Studies of microbial ecology have evoked considerable interest in recent years with the natural ecosystem threatened by pollution due to industrialisation, mining etc. Iron mobilisation in a mangrove ecosystem is a complex process. There are a number of factors affecting mobilisation of iron in mangrove swamps, like the pH of soil, dissolved oxygen, iron source, etc. Our paper describes experiments designed to look for the presence of iron-reacting bacteria in mining area of Goa, and their activity was compared with iron bacteria found in the mangrove regions of the Konkan (non-mining) area. It was observed that the activity of both iron-oxidising and iron-reducing bacteria was higher in mining areas compared to that in non-mining areas, since ample substrate was available in the former.
AN: 3545296
638 of 1521
TI: Measurements of seasonal rates and annual budgets of organic carbon fluxes in an Antarctic coastal environment at Signy Island, South Orkney Islands, suggest a broad balance between production and decomposition
AU: Nedwell,-D.B.; Walker,-T.R.; Ellis-Evans,-J.C.; Clarke,-A.
AF: Dep. Biol., Univ. Essex, Colchester CO4 3SQ, UK
SO: APPL.-ENVIRON.-MICROBIOL. 1993 vol. 59, no. 12, pp. 3989-3995
LA: English
ER: M (Marine)
AB: The authors report here the first comprehensive seasonal study of benthic microbial activity in an Antarctic coastal environment. Measurements were made from December 1990 to February 1992 of oxygen uptake and sulfate reduction by inshore coastal sediments at Signy Island, South Orkney Islands, Antarctica. From these measurements the rate of benthic mineralization of organic matter was calculated. In addition, both the deposition rate of organic matter to the bottom sediment and the organic carbon content of the bottom sediment were measured during the same period. Organic matter input to the sediment was small under winter ice cover, and the benthic respiratory activity and the organic content of the surface sediment declined during this period as available organic matter was depleted. On an annual basis, about 32% of benthic organic matter mineralization was anoxic, but the proportion of anoxic compared with oxic mineralization increased during the winter as organic matter was increasingly buried by the amphipod infauna. Fresh organic input occurred as the sea ice melted and ice algae biomass sedimented onto the bottom, and input was sustained during the spring after ice breakup by continued primary production in the water column. The benthic respiratory rate and benthic organic matter content correspondingly increased towards the end of winter with the input of this fresh organic matter. The rates of oxygen uptake during the southern summer (80 to 90 mmol of O sub(2) m super(-2)/day) were as high as those reported for other sediments at much higher environmental temperatures, and the annual mineralization of organic matter was equally high (12 mol of C m super(-2)/year). Seasonal variations of benthic activity in this antarctic coastal sediment were regulated by the input and availability of organic matter and not by seasonal water temperature, which was relatively constant at between -1.8 and 0.5 degree C. We conclude that despite the low environmental temperature, organic matter degradation broadly balanced organic matter production, although there may be significant interrannual variations in the sources of the organic matter inputs.
AN: 3539852
639 of 1521
TI: Isotopic and biochemical composition of particulate organic matter in a shallow water estuary (Great Ouse, North Sea, England)
AU: Fichez,-R.; Dennis,-P.; Fontaine,-M.F.; Jickells,-T.D.
AF: Cent. ORSTOM Tahiti, B.P. 529, Papeete, Tahiti, French Polynesia
CO: 2. Int. Symp. on the Biogeochemistry of Model Estuaries: Estuarine Processes in Global Climate Change [np] [nd]
SO: MAR.-CHEM. 1993 vol. 43, no. 1-4, pp. 263-276
LA: English
ER: M (Marine); B (Brackish)
AB: The biogeochemistry of particulate organic matter was studied in the Great Ouse estuary draining to the North Sea embayement known as the Wash from March 1990 to January 1991. Eleven locations were sampled monthly on a 50 km transect across the shallow estuary from the tidal weir to the middle of the Wash. Particulate organic carbon (POC) and total carbohydrate, protein and lipid analyses were combined with the determination of stable carbon isotopes. delta super(13)C often increased from -30ppt in the river to -22ppt in the tidal freshwater reach. The mixing zone between fresh and marine tidal waters displayed only a slight increase in delta super(13)C to -19ppt. The change in delta super(13)C values in the freshwater tidal reach demonstrated that mixing of riverborne and marine suspended POC was not the only process affecting the carbon stable isotope composition. Complementary sources, interfering considerably with the two end-member sources, may be identified as autochthonous primary production and resuspension of sediment that may be transported upstream. The respective importance of these sources is subject to seasonal variation. From March to August, high concentrations in carbohydrate and protein through the whole estuary indicate that despite turbidity significant primary production occurred. The proportional importance of the uncharacterized fraction of POC, which is considered as complex organic matter, was high from September to January and low from March to August. During most of the year, the biochemical compositions of particulate organic matter in the turbidity maximum and the rest of the estuary were similar. This contradicted the principle that owing to the long residence times of particles degradation processes largely dominate the production processes within the turbidity maximum. The occurrence of significant in situ production in such shallow water estuaries may partially compensate for the degradation of suspended particulate organics, resulting in a complex relationship between the biogeochemical cycling and the fate of nutrients.
AN: 3539734
640 of 1521
TI: Nutrient processing and the development of tidal creek ecosystems
AU: Dame,-R.F.; Gardner,-L.R.
AF: Coast. Carolina Coll. Univ. South Carolina, Conway, SC 29526, USA
CO: 2. Int. Symp. on the Biogeochemistry of Model Estuaries: Estuarine Processes in Global Climate Change [np] [nd]
SO: MAR.-CHEM. 1993 vol. 43, no. 1-4, pp. 175-183
LA: English
ER: M (Marine)
AB: The North Inlet marsh-estuarine system encompasses the spectrum of interaction between the ocean and the uplands typical of the southeastern United States. The system is an ebb-dominated, bar-built estuary with good flow connection to the sea and some freshwater input. The North Inlet basin has evolved from a forested, relic, beach-ridge terrain under a regime of slowly rising sea level (2 mm/year). This mode of development is supported by historic tide gage data, super(210)Pb dating of sediment cores, the presence of spodic soil horizons and tree roots at shallow depths beneath the marsh surface, and the presence of relic 'cat eye' ponds at the edge of the salt marsh. As sea level rises, the boundary between forest and salt marsh recedes upslope and forest spodosols are gradually transformed into marsh soils by salinization, the deposition and mixing of marine mud into the upper horizons of the forest soil and the accumulation of reduced sulfur via sulfate reduction. As a forest watershed is transformed into a salt-marsh basin, the hydraulic geometry of the original, black-water (fresh) stream increases to accommodate the increasing volumes of tidal discharge. Forest sands move seaward while marine muds are transported into the basin. As water moves between the forest and the sea, it passes through creeks in different developmental stages. Large mature creeks interact with the ocean while young, ephemeral creeks drain the uplands and intertidal marsh zones. Intermediate stage creeks connect these two and are characterized by the presence of oyster reefs. Net nutrient fluxes appear to be different in each developmental stage.
AN: 3539727
641 of 1521
TI: The biogeochemistry of nutrients and trace metals in Hood Canal, a Puget Sound fjord
AU: Paulson,-A.J.; Curl,-H.C.,Jr.; Feely,-R.A.
AF: Spokane Res. Cent., U.S. Bur. Mines, E. 315 Montgomery Ave., Spokane, WA 99207-2291, USA
CO: 2. Int. Symp. on the Biogeochemistry of Model Estuaries: Estuarine Processes in Global Climate Change [np] [nd]
SO: MAR.-CHEM. 1993 vol. 43, no. 1-4, pp. 157-173
LA: English
ER: M (Marine); B (Brackish)
AB: The summer stratification of the surface layer of much of Hood Canal (a Puget Sound fjord) results in a surface layer low in nutrients and a deep layer low in dissolved oxygen and enriched in nutrients. Deviations from the dissolved oxygen:nutrient linear relationships are manifestations of several chemical and biological processes. The low dissolved oxygen concentrations (50 mu mol) result in the redistribution of Fe in the sediment column while Mn is redistributed within the water column. Trace metals are also taken up by organisms in the surface layer and regenerated in the deep layer in the order Zn >> Cd > Cu = Ni. Regenerated Zn is adsorbed on to resuspended bottom sediments that are enriched in Fe oxyhydroxides while Cd is adsorbed throughout the water column. Particulate distributions of Cu and Ni indicate these metals are also participating in biogeochemical cycles, albeit to a lesser extent.
AN: 3539726
642 of 1521
TI: Distributional features and fluxes of dissolved nitrogen, phosphorus and silicon in the Hangzhou Bay
AU: Gao,-Shengquan; Yu,-Guohui; Wang,-Yuhen
AF: Second Inst. Oceanogr., SOA, Hangzhou 310012, People's Rep. China
CO: 2. Int. Symp. on the Biogeochemistry of Model Estuaries: Estuarine Processes in Global Climate Change [np] [nd]
SO: MAR.-CHEM. 1993 vol. 43, no. 1-4, pp. 65-81
LA: English
ER: M (Marine); B (Brackish)
AB: Dissolved nitrate, ammonia, nitrite, phosphate and silicate were measured seasonally near Hangzhou Bay mouth and its adjacent area from 1981 to 1982 and in the upper bay from 1989 to 1990. Because of agricultural activities and increasing discharge of industrial and domestic wastes in that area, the dissolved inorganic nitrogen (average 59.5 mu mol) and phosphorus (average 1.26 mu mol) were significantly higher in the Hangzhou Bay than in the other estuaries, while the silicate level corresponded to the global mean value. The nutrient distributions and variations were dominated by different controls in the different seasons, depending mainly on tidal conditions, river flow and their estuarine processes. The nutrient behaviors of dissolved nitrate, phosphate and silicate were different for each nutrient in the Hangzhou Bay. Silicate was closely conservative in most cases; nitrate exhibited marked biological removal at intermediate salinity and phosphate seemed to be buffered by the suspended sediments. The effluxes of dissolved inorganic nitrogen, phosphorus and silicon were estimated to be about 63 x 10 super(3) tons N/year, 2.8 x 10 super(3) tons P/year and 160 x 10 super(3) tons Si/year, respectively.
AN: 3539721
643 of 1521
TI: Distribution and composition of particulate organic matter in the Ross Sea (Antarctica)
AU: Fabiano,-M.; Povero,-P.; Danovaro,-R.
AF: Dip. Biol. Anim. Ecol., Univ. Cagliari, V. le Poetto 1, Cagliari, Italy
SO: POLAR-BIOL. 1993 vol. 13, no. 8, pp. 525-533
LA: English
ER: M (Marine)
AB: The biochemical composition and spatial distribution of particulate organic matter (POM) were studied in the Ross Sea (Antarctica) in summer 1989 to assess the quantitative role of organic carbon fractions in the cycling of organic matter in the water column. Large differences in chemical composition were observed between surface and deep layers. The results indicated that, despite large geographical differences, POM was quite homogeneous, of phytoplankton origin and mostly detrita1. Different ratios were used to investigate the changes in biochemical composition of particulate organic matter in relation to the ice-melting: C:N (organic carbon: organic nitrogen ratio) and C-POM:POC (sum of carbohydrate, protein and lipid carbon: total organic carbon ratio) were used to analyse the percentage of refractory organic material. PPRT:PCHO (protein: carbohydrate ratio) were used to establish POM "age" and RNA : DNA ratios as a relative measure of particulate activity; POC:Chla and N-PPRT:Chla ratios were used to estimate the autotrophic contribution to the suspended particulate organic matter. Despite its low caloric value (5.3 Kcal/g POM), an high caloric content in the photic layer (1.6 Kcal/m super(3) of POM and 2.5 Kcal/m super(3) of POC) was found thus indicating that a large amount of food was available in highter tropic levels.
AN: 3538876
644 of 1521
TI: Applications of analytical chemistry to oceanic carbon cycle studies
CA: National Research Counc., Washington, DC (USA)
SO: WASHINGTON,-DC-USA NATIONAL-ACADEMY-PRESS 1993 85 pp
LA: English
ER: M (Marine)
AB: This report highlights the state of the art of measurement technologies offering new promise for ocean measurements. In particular, the group focused on new techniques for measuring seawater analytes that are important for understanding key aspects of the ocean's role in the global carbon cycle. The committee also noted other seawater analytes whose improved measurement would contribute to a better understanding of ocean processes. The report does not encompass all areas of chemical oceanography; instead, it highlights a subset of the possible measurements that could be useful for obtaining improved understanding of the global carbon cycle. The report focuses on in situ measurements of dissolved analytes in seawater that might not be feasible in the near future but could play an important role in global ocean observations of the future. The committee believes that the most difficult problem is in designing sensors of the desired selectivity, stability, and sensitivity for dissolved analytes in the open ocean. This report identifies technical hurdles and opportunities and discusses the role that government and academia can play in overcoming the nontechnical barriers to successful research, development, and transfer of these technologies to the ocean science community.
AN: 3538833
645 of 1521
TI: A review of the export of carbon in river water: Fluxes and processes
AU: Hope,-D.; Billett,-M.F.; Cresser,-M.S.
AF: Dep. Plant Soil Sci., Univ. Aberdeen, Cruickshank Build., Aberdeen AB9 2UD, UK
SO: ENVIRON.-POLLUT. 1994 vol. 84, no. 3, pp. 301-324
LA: English
ER: F (Freshwater)
AB: This review summarizes data on exports of carbon from a large number of temperate and boreal catchments in North America, Europe and New Zealand. Organic carbon losses, usually dominated by dissolved organic matter, show relatively little variation, most catchments exporting between 10 and 100 kg C/ha/yr. Inorganic carbon exports occur at a similar rate. However, a lack of information on the flux of particulate organic carbon and dissolved CO sub(2) is highlighted, particularly for rivers in Europe. Processes regulating the flux of organic carbon to streams and its subsequent fate in-stream are reviewed, along with the effects of land use and acidification on these processes. The size of the global riverine flux of carbon in relation to the global carbon cycle and the possible effects of environmental change on the export of carbon in rivers are considered.
AN: 3538111
646 of 1521
TI: Atmospheric input of inorganic nitrogen to Delaware Bay
AU: Scudlark,-J.R.; Church,-T.M.
AF: Coll. Mar. Stud., Univ. Delaware, 700 Pilottown Rd., Lewes, DE 19958, USA
SO: ESTUARIES 1993 vol. 16, no. 4, pp. 747-759
LA: English
ER: M (Marine); B (Brackish)
AB: The coastal waters of the Mid-Atlantic region of the United States receive inputs of atmospheric pollutants as a consequence of being located downwind from major industrial and urban emissions. These inputs are potentially the largest received by any marine area of the country. Of current interest is the atmospheric input of dissolved inorganic nitrogen (DIN = NO sub(3) super(-) + NH sub(4) super(+)). We have conducted a first-order examination of the magnitude of atmospheric DIN deposition relative to other large-scale inputs for Delaware Bay, a partially urbanized mid-Atlantic coastal plain estuary. The following loading terms: direct atmospheric deposition, indirect atmospheric loading, urban point discharges, fluvial input, benthic flux, and salt marsh export were evaluated. On an annual basis, municipal-industrial effluents provide a dominant source (ca. 40%) of the DIN input to the estuary. Total (wet plus dry) atmospheric deposition accounts for about 15% of the total annual DIN inputs. However, during summer, which is characterized by low river-flow and seasonally maximum atmospheric loading, this figure increases to around 25%. Although atmospheric input can satisfy only a fraction of the primary production demands, this summer flux may represent an ecologically important source of external DIN, half of which is directly deposited to surface photic zones where it is readily available for biological uptake.
AN: 3536891
647 of 1521
TI: Beaver pond biogeochemistry: Acid neutralizing capacity generation in a headwater wetland
AU: Cirmo,-C.P.; Driscoll,-C.T.
AF: Dep. Civ. and Environ. Eng., Syracuse Univ., Syracuse, NY 13244, USA
SO: WETLANDS 1993 vol. 13, no. 4, pp. 277-292
LA: English
ER: F (Freshwater)
AB: A beaver pond and its associated inlet and outlet waters in the Adirondack Mountains of New York were monitored for major chemical solutes for 26 months in an effort to quantify underlying chemical controls on the production and consumption of acid neutralizing capacity (ANC). The pond was a net annual sink for inlet Al, SO sub(4) super(2-), NO sub(3) super(-), and H sub(4)SiO sub(4). The pond was a net annual source of dissolved organic carbon (DOC), NH sub(4) super(+), and Fe super(2+). Losses of ANC resulting from Al and basic cation retention, as well as organic anion release (RCOO super(-)) associated with DOC, were more than offset by SO sub(4) super(2-) and NO sub(3) super(-) retention and Fe super(2+) and NH sub(4) super(+) release, resulting in a net production of ANC. Rates of ANC generation were 120 meq m super(-2)/yr and 310 meq m super(-2)/yr, respectively (based on pond surface area), for the non-summer (October-June) and summer (July-September) periods. Seasonal variations in ANC in the outlet stream were largely associated with Fe super(2+) and DOC release, while ANC in the upland inlet stream was associated with Al, NO sub(3) super(-), and basic cations, with much less seasonal variation. Controls on stream chemistry were temporally and longitudinally different for the inlet and outlet streams. The shift to seasonal control of outlet stream ANC by processes associated with organic matter decomposition reactions and anaerobic zone nutrient transformations may be characteristic of headwater wetlands in temperate zones with seasonal temperature extremes. Beaver impoundments and wetlands may also be important in the upstream mobilization or retention of geologically bound solutes like Al, Fe, and H sub(4)SiO sub(4). Headwater wetlands, as sinks for solutes associated with acidic deposition and watershed acidification (i.e., SO sub(4) super(2-), NO sub(3) super(-), and Al), may play a role in the amelioration of the effects of these solutes on downstream receiving waters and associated biota. Depending on their location in relation to drainage patterns, these ponded systems may influence the nutrient dynamics of receiving waters through nitrogen transformations and organic carbon cycling.
AN: 3536863
648 of 1521
TI: The internal consistency of CO sub(2) measurements in the Equatorial Pacific
AU: Millero,-F.J.; Byrne,-R.H.; Wanninkhof,-R.; Feely,-R.; Clayton,-T.; Murphy,-P.; Lamb,-M.F.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Univ. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: MAR.-CHEM. 1993 vol. 44, no. 2-4, pp. 269-280
LA: English
ER: M (Marine)
AB: During a recent NOAA JGOFS Equatorial Pacific cruise all four analytical parameters of the carbonate system were measured-pH, total alkalinity (TA), total carbon dioxide (TCO sub(2)), and the fugacity of carbon dioxide (fCO sub(2)). The measurements made during leg 2 on surface waters have been used to examine the internal consistency of the carbon dioxide system in these waters. The internal consistency of the measurements was examined by using various inputs of the measured parameters (pH-TA, pH-TCO sub(2), pH-fCO sub(2)-TA, fCO sub(2)-TA, fCO sub(2)-TCO sub(2) and TA-TCO sub(2)) to calculate the components of the CO sub(2) system. The results indicate that the measurements have an internal consistency of plus or minus 0.003-0.006 in pH, plus or minus 5-7 mu mol/kg in TA, plus or minus 5-7 mu mol/kg in TCO sub(2) and plus or minus 6-9 mu Atm in fCO sub(2) if reliable constants are used for the dissociation of carbonic acid in seawater. These results indicate that our present understanding of the thermodynamics of the carbonate system in seawater is close to the present accuracy in measuring the various parameters of the system ( plus or minus 0.002 in pH, plus or minus 4 mu mol/kg in TA, plus or minus 2 mu mol/kg in TCO sub(2) and plus or minus 2 mu Atm in fCO sub(2)).
AN: 3536790
649 of 1521
TI: Biogenic sulfur compounds in seawater and the atmosphere of the Antarctic region
AU: Staubes,-R.; Georgii,-H.W.
AF: Inst. Meteorol. and Geophys., Johann Wolfgang Goethe Univ., 6000 Frankfurt/Main 1, FRG
CO: Symp. on the Tropospheric Chemistry of the Antarctic Region, Boulder, CO (USA), Jun 1991
SO: TELLUS-B-CHEM.-PHYS.-METEOROL. 1993 vol. 45B, no. 2, pp. 127-137
NT: Special Issue II.
LA: English
ER: M (Marine)
AB: Shipboard measurements of dimethyl sulfide (DMS), carbonyl sulfide (COS) and carbon disulfide (CS sub(2)) in seawater and the marine boundary layer were performed during a cruise between Punta Arenas (Chile) and Cape Town (South Africa) through the Weddell Sea in November/December 1990. The DMS concentrations in seawater averaged to 71 ngS/l, atmospheric DMS mixing ratios showed a range between 2 and 1048 pptv. The COS levels in seawater showed a mean of 3.5 ngS/l with minor variability. The concentrations of CS sub(2) in the remote marine boundary layer were below the detection limit of 7 pptv, with enhanced concentrations of about 35 pptv observed in air masses influenced by continental inputs.
AN: 3536744
650 of 1521
TI: Bromoalkane production by Antarctic ice algae
AU: Sturges,-W.T.; Sullivan,-C.W.; Schnell,-R.C.; Heidt,-L.E.; Pollock,-W.H.
AF: Coop. Inst. Res. Environ. Sci., Univ. Colorado, Boulder, CO 80309-0449, USA
CO: Symp. on the Tropospheric Chemistry of the Antarctic Region, Boulder, CO (USA), Jun 1991
SO: TELLUS-B-CHEM.-PHYS.-METEOROL. 1993 vol. 45B, no. 2, pp. 120-126
NT: Special Issue II.
LA: English
ER: M (Marine)
AB: Ice microalgae, collected from the underside of annual sea ice in McMurdo Sound, Antarctica, were found to contain and release to seawater a number of brominated hydrocarbons. These included bromoform, dibromomethane, mixed bromochloromethanes, and methyl bromide. Atmospheric measurements in the McMurdo Sound vicinity revealed the presence of bromoform and methyl bromide in the lower atmosphere, with lowest concentrations inland, further indicating that biogenic activity in the Sound is a source of organic bromine gases to the Antarctic atmosphere. This may have important implications for boundary layer chemistry in Antarctica. In the Arctic, the presence of bromoform has been linked to loss of surface ozone in the spring. We report here preliminary evidence for similar surface ozone loss at McMurdo Station.
AN: 3535612
651 of 1521
TI: Global cyclostratigraphy: A model of carbonate growth patterns
AU: Li,-Y.Y.; Lerche,-I.; Perlmutter,-M.A.
AF: Dep. Geol. Sci., Univ. South Carolina, Columbia, SC 29208, USA
SO: MAR.-PET.-GEOL. 1993 vol. 10, no. 6, pp. 620-631
LA: English
ER: M (Marine)
AB: Cyclostratigraphy is the study of cyclic depositional patterns produced by climatic and tectonic processes. A global-scale quantitative cyclostratigraphic model is described which simulates carbonate growth patterns controlled by tectonic and climatic processes. The model uses seven factors simulating the effects of physical and chemical environments on the deposition rates of carbonate accumulations. These factors are sea-level change, the rate of basement subsidence, food supply (influence of nutrients), available sunlight, temperature, salinity and dissolved oxygen. The factors are considered as functions of climatic and tectonic processes. The model also integrates Milankovitch-induced short-term climatic changes with the long-term tectonic evolution of basins to examine the potential carbonate accumulation patterns. The two-dimensional computer model results provided here show that: (1) carbonate growth patterns in different climates and under different tectonic processes can be modelled quantitatively; (2) carbonate production increases towards the equator (decreasing latitude) as the temperature and nutrition supply increase in tropical belts, and production changes because of expansion or contraction of the tropical belt in different climatic periods; (3) when matched with the turbidity, the model describes different carbonate accumulation patterns in different climatic patterns; (4) at either abnormally high or low salinity, carbonate accumulation rates decline sharply, and the salinity becomes normal away from the strand line; and (5) cyclic sea-level changes cause a cyclic change of carbonate accumulation. A case study is presented from the Upper Pennsylvanian of Texas. The simulation results indicate that carbonate growth patterns observed from field, well or seismic data are accurately modelled by the quantitative procedure given here.
AN: 3534079
652 of 1521
TI: Distribution and sedimentation of organic matter during the inter-monsoon period off Oman (West Arabian Sea)
AU: Passow,-U.; Peinert,-R.; Zeitzschel,-B.
AF: Mar. Sci. Inst., Univ. California, Santa Barbara, CA 93106, USA
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 833-849
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Temperature, salinity and nutrient concentrations, as well as suspended particles and vertical flux of particles were measured during a drogue study in the spring inter-monsoon period of 1987 off Oman. In addition, horizontal variability of temperature, nutrients and in vivo fluorescence were documented during two grid surveys. An oligotrophic type of system typical for low latitudes with a stratified water column was anticipated at this season. However, although no upwelling occurred, some stations exhibited high near-surface chl a concentrations (2 mu g l super(-1)), a predominance of diatoms and high sedimentation rates (up to 0.4 gC m super(-2) day super(-1)) comparable to upwelling regimes or spring blooms of higher latitudes. Different stages of the development and decline of a diatom bloom and of the transition towards more oligotrophic conditions were found to coexist on scales of 10 nautical miles or less.
AN: 3531584
653 of 1521
TI: Short-term sedimentation patterns in the northern Indian Ocean
AU: Pollehne,-F.; Zeitzschel,-B.; Peinert,-R.
AF: Inst. Ostseeforschung, Seestr. 15, O-2530, Rostock-Warnemuende, FRG
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 821-831
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: The flux of particles from the photic zone was monitored in one open ocean and two shelf stations in the northern Indian Ocean by means of drifting sediment traps in the inter-monsoon period, from March to June 1987. Samples were collected over daily intervals and analysed for organic carbon, nitrogen, total phosphorus and silica. Flux rates of all elements differed by up to a factor of 10 between the Oman shelf and the open ocean area. Mean rates of carbon sedimentation were 13.6 and 1.7 mmol C/m super(2)/day, respectively. On the Pakistan shelf, however, sedimentation rates were in the same low range as in the open ocean. These differences, particularly between the two shelf regions, were due to the different types of pelagic systems in the respective photic zones. The presence of nitrate in surface water of the Oman shelf permitted "new" production, which consequently led to enhanced particle export. In the open ocean and the Pakistan shelf, typical tropical recycling systems retained material by intense regeneration of nutrients in the surface layer. These differences also were reflected in the composition of the sedimenting particles. Changes in production-respiration equilibria in the photic zone lead to rapid shifts in the carbon/silica and carbon/nitrogen ratios of trapped material. Thus short term sedimentation measurements can provide valuable information on structural and functional variations in pelagic productivity.
AN: 3531583
654 of 1521
TI: Aspects of horizontal distribution and diet of myctophid fish in the Arabian Sea with reference to the deep water oxygen deficiency
AU: Kinzer,-J.; Boettger-Schnack,-R.; Schulz,-K.
AF: Inst. Meereskd., Univ. Kiel, D-2300 Kiel, FRG
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 783-800
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Horizontal distribution of myctophid fishes were studied from two transects in the Arabian Sea in 1987. Species numbers exhibited a south-north decline in diversity, with only half of the fish taxa occupying the northeastern region. Diaphus arabicus was the dominant species both in the south and north. All recorded myctophid fish species migrate in a diel pattern, residing during daytime at depths of extremely low oxygen levels (<0.1 ml O sub(2)/l) and foraging in the oxygen-rich surface layer at night. Feeding patterns were determined for the six most abundant myctophid species. All species appeared to be opportunistic predators that prey on a comparatively narrow food spectrum consisting principally of small to medium sized copepods. Numerically, non-calanoid copepods (with Oncaea conifera and O. venusta dominating) made up to 70% of the diet of D. arabicus and Bolinichthys longipes. Of the 26 calanoid copepod species identified from the six myctophid taxa, the genera Euchaeta, Pleuromamma and Candacia generally dominated in the stomachs, with P. indica constituting between 21 and 95% (by numbers) of the calanoid copepod prey.
AN: 3531582
655 of 1521
TI: A comparative study on the influence of the pycnocline on the vertical distribution of fish larvae and cephalopod paralarvae in three ecologically different areas of the Arabian Sea
AU: Roepke,-A.; Nellen,-W.; Piatkowski,-U.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Div. Mar. Biol. and Fish., Univ. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: BIOGEOCHEMICAL-CYCLING-IN-THE-NORTHWESTERN-INDIAN-OCEAN. Burkill,-P.H.;Mantoura,-R.F.C.;Owens,-N.J.P.-eds. 1993 vol. 40, no. 3 pp. 801-819
ST: DEEP-SEA-RES.-2-TOP.-STUD.-OCEANOGR. vol. 40, no. 3
LA: English
ER: M (Marine)
AB: Zooplankton sampling took place during cruise 5 Leg 3 of the R.V. Meteor (March-June 1987) in three hydrographically and ecologically different areas of the Arabian Sea (Indian Ocean): an upwelling area at the coast of Oman; an oligotroph area in the central Arabian Sea; and a shelf area off the coast of Pakistan. All three areas were expected to have similar ichthyoplankton and cephalopod components and similar light conditions. These are important prerequisites for the present comparative study, which is concerned with the importance of the structure of the water column (physical stability and prey availability), compared with the influence of the light intensity (day/night) on the vertical distribution of species and size classes of fish larvae and cephalopod paralarvae in the subtropical pelagial.
AN: 3531581
656 of 1521
TI: Modeling study of the vertical distribution and transport of manganese in Puget Sound
AU: Cudaback,-C.N.; Paulson,-A.J.; Lavelle,-J.W.
CA: National Oceanic and Atmospheric Adm., Seattle, WA (USA). Pacific Marine Environmental Lab.
SO: NOAA-TECH.-MEMO. 1991 27 pp
RN: NOAA-TM-ERL-PMEL-93 (NOAATMERLPMEL93)
LA: English
ER: M (Marine); B (Brackish)
AB: The fate of many toxic trace metals in estuaries is controlled by their adsorption onto manganese enriched particles, although Mn itself is not considered toxic. The geochemical cycle of estuarine manganese has been studied by a variety of approaches. A one-dimensional vertical distribution and transport model tracing the fate of Mn in dissolved and fine particulate forms and Mn associated with rapidly settling aggregates is developed and results are compared with measurements. Those measurements take the form of vertical profiles of dissolved and particulate Mn concentrations measured in the water column at one station in central Puget Sound. The model provides a framework relating sources, sinks, distributions and fluxes of Mn in a quantitative manner. The model accurately reproduces the vertical distributions of dissolved and particulate Mn, but shows excessive vertical flux of Mn. The model suggests that particles in each of two size classes should carry nearly the same loading of Mn, but measurements show significantly less Mn loading on macroaggregates than on fine particles. Mn budgets from model results allow comparison of major Mn fluxes in Puget Sound. The flux of Mn into the central main basin in particulate form is about half the diffusive flux of dissolved Mn from the bottom. A significant fraction of the riverine flux of particulate Mn is advected out of Puget Sound in dissolved form.
AN: 3531554
657 of 1521
TI: Amino acid composition of suspended particles, sediment-trap material, and benthic sediment in the Potomac Estuary
AU: Sigleo,-A.C.; Shultz,-D.J.
AF: Pac. Ecosyst. Branch, U.S. EPA, Newport, OR 97365-5260, USA
CO: 11. Bienn. Int. Estuarine Research Conf., San Francisco, CA (USA), 10-14 Nov 1991
SO: TRACE-CONTAMINANTS-AND-NUTRIENTS-IN-ESTUARIES. 1993 vol. 16, no. 3A pp. 405-415
ST: ESTUARIES vol. 16, no. 3A
LA: English
ER: M (Marine); B (Brackish)
AB: Sediment trap deployments in estuaries provide a method for estimating the amount of organic material transported to the sediments from the euphotic zone. The amino acid composition of suspended particles, benthic sediment, and sediment-trap material collected at 2.4 m, 5.8 m, and 7.9 m depths in the Potomac Estuary was determined in stratified summer waters, and in well-mixed oxygenated waters (DO) in late fall. The total vertical flow, or flux, of material into the top traps ranged from 3 g/m super(2)/d in August to 4.9 g/m super(2)/d in October. The carbon and nitrogen fluxes increased in the deepest traps relative to the surface traps during both sampling periods, along with that of the total material flux (up to 47.3 g/m super(2)/d in the deepest trap), although the actual weight percent of organic carbon and organic nitrogen decreased with depth. Amino acid concentrations ranged from 129 mg/g in surface water particulate material to 22 mg/g in particulate material in 9-m-deep waters and in the benthic sediment. Amino acid concentrations from 2.4-m-depth sediment traps averaged 104 plus or minus 29 mg/g in stratified waters and 164 plus or minus 81 mg/g in well-mixed waters. The deep trap samples averaged 77.3 plus or minus 4.8 mg/g amino acids in summer waters and 37 plus or minus 16 mg/g in oxygenated fall waters. Amino acids comprised 13% to 39% of the organic carbon and 12% to 89% of the organic nitrogen in these samples. Analysis of the flux results suggest that resuspension combined with lateral advection from adjacent slopes can account for up to 27% of the material in the deep traps when the estuary was well-mixed and unstratified. When the estuary was stratified in late summer, the amino acid carbon produced by primary productivity in the euphotic zone decreased by 85% (86% for total organic carbon) at the pycnocline at 6 m depth, leaving up to 15% of the vertical organic flux available for benthic sediment deposition.
AN: 3530945
658 of 1521
TI: Silver in San Francisco Bay estuarine waters
AU: Smith,-G.J.; Flegal,-A.R.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
CO: 11. Bienn. Int. Estuarine Research Conf., San Francisco, CA (USA), 10-14 Nov 1991
SO: TRACE-CONTAMINANTS-AND-NUTRIENTS-IN-ESTUARIES. 1993 vol. 16, no. 3A pp. 547-558
ST: ESTUARIES vol. 16, no. 3A
LA: English
ER: M (Marine); B (Brackish)
AB: Spatial gradients of silver concentrations in the surface waters of San Francisco Bay reveal substantial anthropogenic perturbations of the biogeochemical cycle of the element throughout the estuarine system. The most pronounced perturbations are in the south bay, where dissolved (<0.45 mu m) silver concentrations are as high as 250 pM. This is more than one order-of-magnitude above baseline concentrations in the northern reach of the estuary (6 pM) and approximately two orders-of-magnitude above natural concentrations in adjacent coastal waters (3 pM). The excess silver is primarily attributed to wastewater discharges of industrial silver to the estuary on the order of 20 kg/d. The contamination is most evident in the south bay, where wastewater discharges of silver are on the order of 10 kg/d and natural freshwater discharges are relatively insignificant. The limited amount of freshwater flushing in the south bay was exacerbated by persistent drought conditions during the study period. This extended the hydraulic residence time in the south bay ( greater than or equal to 160 d), and revealed the apparent seasonal benthic fluxes of silver from anthropogenically contaminated sediments. These were conservatively estimated to average ) 16 nmol m super(-2)/d in the south bay, which is sufficient to replace all of the dissolved silver in the south bay within 22 d. Benthic fluxes of silver throughout the estuary were estimated to average ) 11 nmol m super(-2)/d, with an annual input of approximately 540 kg/yr of silver to the system. This dwarfs the annual fluvial input of silver during the study period (12 kg yr super(-1)), and is equivalent to approximately 10% of the annual anthropogenic input of silver to the estuary (3,700-7,200 kg/yr). It is further speculated that benthic fluxes of silver may be greater than or equal to waste water fluxes of silver during periods of intense diagenic remobilization. However, all inputs of dissolved silver to the estuary are efficiently sorbed by suspended particulates, as evidenced by the relatively constant conditional distribution coefficient for silver throughout the estuary (K sub(d) ) 10 super(5)).
AN: 3530930
659 of 1521
TI: Trace contaminants and nutrients in estuaries: The importance of process interdependence
AU: Kuwabara,-J.S.; Baker,-J.E.
AF: Water Resour. Div., U.S. Geol. Surv., 345 Middlefield Rd., Mail Stop 465, Menlo Park, CA 94025, USA
CO: 11. Bienn. Int. Estuarine Research Conf., San Francisco, CA (USA), 10-14 Nov 1991
SO: ESTUARIES 1993 vol. 16, no. 3A, 190 pp
LA: English
ER: M (Marine); B (Brackish)
AB: This issue is dedicated to studies that attempt to expand our understanding of how inorganic and organic solutes are transported, transformed, and distributed in estuaries.
AN: 3530928
660 of 1521
TI: Evaluation of super(55)Fe as a tracer of Fe(III) reduction in aquatic sediments
AU: Roden,-E.E.; Lovley,-D.R.*
AF: Water Resour. Div., 430 Natl. Cent., USGS, Reston, VA 22092, USA
SO: GEOMICROBIOL.-J. 1993 vol. 11, no. 1, pp. 49-56
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The potential utility of super(55)Fe as a tracer for Fe(III) reduction in aquatic sediments was evaluated using freshwater sediments from the Potomac River, Md, in which Fe(III) reduction was the predominant terminal electron accepting process. In laboratory incubations of sediments amended with poorly crystalline super(55)Fe(III) oxide, the accumulation of super(55)Fe in Fe(II) over time paralleled Fe(II) production. However, within 1 h of addition of super(55)Fe(III) oxide, significant quantities of super(55)Fe were recovered in extractable (1 M sodium acetate, pH 5) and soluble Fe(II) pools. There was proportionately more super(55)Fe(II) activity in sediments with higher Fe(II) concentrations. These results suggest that there was rapid isotopic exchange between super(55)Fe in poorly crystalline Fe(III) oxide and the Fe(II) pools. Because of this exchange, super(55)Fe could not be used to trace Fe(III) reduction in sediments in the manner that super(35)SO sub(4) super(2-) is used to trace sulfate reduction. Although accumulation of super(55)Fe in Fe(II) pools paralleled unlabeled Fe(II) production, given the relative ease with which Fe(II) pools in sediments can be measured there is no apparent advantage to using super(55)Fe to follow Fe(III) reduction.
AN: 3530925
661 of 1521
TI: Fluorescence of dissolved organic matter: A comparison of North Pacific and North Atlantic Oceans during April 1991
AU: Hoge,-F.E.; Swift,-R.N.; Yungel,-J.K.; Vodacek,-A.
AF: Goddard Space Flight Cent., Wallops Flight Facil., Wallops I., VA, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS 1993 vol. 98, no. C12, pp. 22779-22787
LA: English
ER: M (Marine)
AB: Profiles of airborne-laser-induced fluorescence emission from dissolved organic matter in the upper ocean have been produced and compared for the Southern California Bight (SCB) and the Mid-Atlantic Bight (MAB). Findings were as follows. (1) The fluorescent components of dissolved organic matter (FDOM) are present in easily measurable quantities from near shore to well over 300 km offshore in the SCB and are likewise easily measurable in the coastal, shelf, slope, and Gulf Stream waters of the MAB. (2) The range of FDOM in the MAB is considerably greater than that in the SCB. (3) The lowest FDOM levels observed in the SCB were higher than those found in the Gulf Stream. (4) The onshore-to-offshore spatial gradient of the FDOM was found to be considerably lower in the SCB than in the MAB, with the highest levels of FDOM being found immediately adjacent to the coast in the MAB. This suggests that the water adjacent to the SCB shoreline is not as strongly influenced by terrestrial and estuarine sources of FDOM as the MAB is. (5) The spatial distribution of the FDOM within both the SCB and the MAB is frequently coherent with the spatial distribution of chlorophyll determined from the concurrent airborne-laser-induced phytoplankton pigment fluorescence measurements. However, distinct noncoherency is sometimes observed, especially at water mass boundaries.
AN: 3529532
662 of 1521
TI: Salt-marsh processes: A review
AU: Vernberg,-F.J.
AF: Belle W. Baruch Inst. Mar. Biol. and Coast. Res., Univ. South Carolina, Columbia, SC 29208, USA
SO: ENVIRON.-TOXICOL.-CHEM. 1993 vol. 12, no. 12, pp. 2167-2193
LA: English
ER: M (Marine); B (Brackish)
AB: Salt marshes are found between the high tide and the near-shore sublittoral zones along the coasts and up estuaries of continents, primarily in the temperate zone. They flourish in regions where much silt is carried to the coastal regions by rivers or where geological processes favor erosion and suspension of silt. Salt marshes have multiple ecological and economic values. They have a high rate of primary productivity; provide habitats for many marine species (including commercially important organisms); assist in flood and erosion control; lessen the effects of stormwater surges; and improve water quality by filtering pollutants, excess nutrients, and disease-causing microorganisms. In addition, this habitat is used for recreational and educational purposes by millions of people who spend millions of dollars. Although the myriad functions and uses of this habitat attest to its tremendous importance, legal protection of salt marshes varies significantly throughout the world. Salt-marsh processes are governed by the interactions between "natural" physical, chemical, geological, and biological factors. Of importance to ecotoxicologists and other scientists is understanding the intimate interaction between these various abiotic and biotic factors. This paper reviews the functional processes of salt marshes and discusses recent research advances under the following major headings: (a) physical, geological, and chemical factors; (b) biotic factors (including productivity of vascular plants, phytoplankton, epibenthic algae, and attached macrophytes; secondary production of primary and secondary consumers; and decomposition; (c) material cycling, biogeochemical cycling, and nutrients; (d) long-term changes; and (e) interaction with adjacent ecosystems.
AN: 3529432
663 of 1521
TI: Attraction of deep-sea amphipods to macrophyte food falls
AU: Lawson,-G.S.; Tyler,-P.A.; Young,-C.M.
AF: Dep. Oceanogr., Univ. Southampton, SO9 5NH, UK
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1993 vol. 169, no. 1, pp. 33-39
LA: English
ER: M (Marine)
AB: Traps baited with plant remains, either Thalassia or Sargassum, were deployed for 30 h on the seabed at depths of 500 and 10 m in the Bahamas. On retrieval, the deep traps had been colonised by three species of amphipod whilst inert controls (traps containing black plastic bags) had attracted only a single specimen of a fourth species. These data suggest that amphipods are attracted to plant debris as food rather than as shelter. Significantly more amphipods were attracted at the deepwater site than at the shallow site. We suggest that algal/seagrass foodfalls are a significant pathway by which energy enters the deep-sea and will be colonised rapidly by deepwater invertebrates.
AN: 3527541
664 of 1521
TI: Tropical marine ecosystems: The microbial component
AU: Chandramohan,-D.
AF: NIO, Dona Paula, Goa 403 004, India
SO: TROPICAL-ECOSYSTEMS:-ECOLOGY-AND-MANAGEMENT. Singh,-K.P.;Singh,-J.S.-eds. DELHI-INDIA WILEY-EASTERN 1992 pp. 241-254
LA: English
ER: M (Marine)
AB: Microbes such as bacteria, fungi and unicellular algae assume greater importance in the tropical marine ecosystems because of their abundance, biomass and activity in a number of chemical and biological processes that provide the driving force for vital biogeochemical cycles. Although the bacteriology of fish has been extensively studied in connection with spoilage, comparatively little work has been done on the role of intestinal flora in fish nutrition. A number of plant and animal diseases have been recognised. Of late isolation of human pathogens from coastal areas has become very common. Many marine microbes have been reported to produce a variety of bioactive compounds. An attempt has been made in this paper to give an overview of the work done in India.
AN: 3527068
665 of 1521
TI: Processes of biogeochemical matter cycle under the conditions of artificial eutrophication
AU: Punning,-J.-M.; Sagris,-A.
AF: Inst. Ecol., Est. Acad. Sci., Kevade St. 2, EE-0031 Tallinn, Estonia
SO: PROC.-ESTON.-ACAD.-SCI.-ECOL. 1993 vol. 3, no. 3, pp. 120-136
LA: English
ER: F (Freshwater)
AB: During the last decades a huge amount of different wastes has accumulated in the lakes in NE Estonia, In order to plan measures for improving the condition of the lakes, it is necessary to understand the mechanisms of processes taking place in the water--sediment boundary. The experiments conducted under the conditions of artificial eutrophication (fertilizers were added to microcosms) showed the existence of different mechanisms of matter cycle. The nutrients introduced during the phase of accelerating growth become immediately involved in the process of photosynthesis. This brings about a rapid increase in the oxygen content, a decrease in water transparency, coagulation, sorption, and destruction of substances. When nutrients are added during the deceleration phase of phytoplankton growth, the nutrients, that are mainly in an inorganic form, are deposited to the bottom from where they are transported back into the euphotic zone during the stagnation and vernal isothermia.
AN: 3526563
666 of 1521
TI: Influence of enhanced CO sub(2) on growth and photosynthesis of the red algae Gracilaria sp. and Gracilaria chilensis
AU: Gao,-K.; Aruga,-Y.; Asada,-K.; Kiyohara,-M.
AF: Hawaii Nat. Energy Inst., 2540 Dole St., Honolulu, HI 96822, USA
SO: J.-APPL.-PHYCOL. 1993 vol. 5, no. 6, pp. 563-571
LA: English
ER: M (Marine)
AB: The influence of elevated CO sub(2) concentrations on growth and photosynthesis of Gracilaria sp. and Gracilaria chilensis was investigated in order to procure information on the effective utilization of CO sub(2). Growth of both was enhanced by CO sub(2) enrichment (air + 650 ppm CO sub(2), air + 1250 ppm CO sub(2)), the enhancement being greater in Gracilaria sp. Both species increased uptake of NO sub(3) super(-) with CO sub(2) enrichment. Photosynthetic inorganic carbon uptake was depressed in Gracilaria chilensis by pre-culture (15 days) with CO sub(2) enrichment, but little affected in Gracilaria sp. Mass spectrometric analysis showed that O sub(2) uptake was higher in the light than in the dark for both species and in both cases was higher in Gracilaria sp. The higher growth enhancement in Gracilaria sp. was attributed to greater depression of photorespiration by the enrichment of CO sub(2) in culture.
AN: 3526524
667 of 1521
TI: Effects of methylated, organic, and inorganic substrates on microbial consumption of dimethyl sulfide in estuarine waters
AU: Wolfe,-G.V.; Kiene,-R.P.
AF: Coll. Oceanic Atmos. Sci., Oceanogr. Admin. Build. 104, Oregon State Univ., Corvallis, OR 97331-5503, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1993 vol. 59, no. 8, pp. 2723-2726
LA: English
ER: M (Marine)
AB: We examined the effects of a variety of amendments on the consumption of (U- super(14)C) dimethyl sulfide in a Georgia salt marsh. Methylated compounds, particularly those with dimethyl groups, significantly inhibited dimethyl sulfide consumption, while nonmethylated substrates had little effect. Dimethyl disulfide and dimethyl ether were the most effective inhibitors tested.
AN: 3525922
668 of 1521
TI: Seasonal benthic microbial activity in the southern North Sea; oxygen uptake and sulphate reduction
AU: Upton,-A.C.; Nedwell,-D.B.*; Parkes,-R.J.; Harvey,-S.M.
AF: Univ. Essex, Dep. Biol., Wivenhoe Park, Colchester, CO4 3SQ, UK
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 101, no. 3, pp. 273-281
LA: English
ER: M (Marine)
AB: From an initial cruise, 6 sites were selected from the 41 sampled to be representative of the major types of sediment in the southern North Sea. The 6 sites in the mixed, frontal and stratified areas of the southern half of the North Sea exhibited a wide range of environmental conditions, particularly sediment type, water depth and organic matter content. Benthic microbial activity, and its seasonal variability, were determined at bimonthly intervals from September 1988 to September 1989. The significance of aerobic and anaerobic respiration in the degradation of organic carbon was investigated by measuring the rate of oxygen uptake and sulphate reduction for each sediment. All sites showed significant rates of oxygen uptake (range 5.3 to 27.8 mmol O sub(2) m super(-2)/d) and sulphate reduction (range 0.05 to 11.8 mmol SO sub(4) m super(-2)/d), and hence of organic matter mineralization. Aerobic respiration accounted for between 47 and 89% of annual organic matter degradation depending on the site, the balance being due to anaerobic sulphate reduction. Benthic mineralisation rates were greatest at a station near the Dogger Bank and one near the Dutch/Belgian coast. However, benthic mineralisation as a proportion of the net annual primary production in the water column was higher at stratified stations in the central North Sea (average 47%) than in the more southerly stations with mixed water columns (average 26%). Estimates of benthic organic mineralisation were used to calculate the magnitude of total benthic mineralisation in the southern half of the North Sea and compared to estimates of net primary production for the same area.
AN: 3524690
669 of 1521
TI: Arsenic in marine environment. Biogeochemistry and ecotoxicology.
OT: L'arsenic en milieu marin. Biogeochimie and ecotoxicologie
AU: Michel,-P.
AF: IFREMER, Cent. Nantes, BP 1049, 44037 Nantes Cedex, France
SO: REPERES-OCEAN PLOUZANE-FRANCE IFREMER-CENTRE-BREST,-SERVICES-DES-EDITIONS 1993 no. 4, 62 pp
LA: French
ER: M (Marine)
AB: Arsenic levels of in the marine environment are high in comparison with other contaminants. Over the past twenty years, a large number of arsenic organic compounds have been identified in the water, sediments and living species. This document constitutes a synthesis of current knowledge on arsenic sources, and contamination levels, on its biogeochemical cycle as well as its toxic effects on human and marine fauna. This paper highlights in particular the effects of phosynthesis on arsenic speciation and its distribution throughout the marine environment. Problems of toxicity in the case of certain phyto- and zooplankton species are identified. Bioaccumulation in seaweeds, molluscs and fishes is documented as well, with special attention to the species encountered in the French coastal waters.
AN: 3523900
670 of 1521
TI: Biogeochemical cycling of metals in freshwater algae from Manaus and Carajas, Brazil
AU: Konhauser,-K.O.; Fyfe,-W.S.
AF: Dep. Geol., Univ. Western Ontario, London, ON N6A 5B7, Canada
SO: ENERGY-SOURCES 1993 vol. 15, no. 4, pp. 595-608
LA: English
ER: F (Freshwater)
AB: Freshwater algae were analyzed in different riverine environments in Manaus and Carajas, Brazil. Filamentous algae from both locations were characterized by enhanced levels of a wide array of heavy metals. A comparison of the two main rivers in the Manaus area indicated that the algal samples from the solute-rich waters of the Rio Solimoes consistently contained higher metal concentrations than in the solute-deficient waters of the Rio Negro. A similar relationship also existed between algal samples collected from forested regions relative to adjacent deforested regions in the Carajas area. In the Rio Negro, diatoms were shown to be the most prolific eucaryotic micro-organisms found in the study area. These siliceous algae were found adhering to a variety of submerged solid substrates, including wood, rocks and leaves. The abundance of these unicellular micro-organisms that the dissolved silicon levels of the Rio Negro were influenced by biological activity.
AN: 3522804
671 of 1521
TI: The trace metal ecology of ichthyofauna in the Rockall Trough, North-eastern Atlantic
AU: Vas,-P.; Gordon,-J.D.M.; Fielden,-P.R.; Overnell,-J.
AF: Dep. Biol. Sci., Univ. Salford, Salford M5 4WT, UK
SO: MAR.-POLLUT.-BULL. 1993 vol. 26, no. 11, pp. 607-612
LA: English
ER: M (Marine)
AB: The concentrations of Cu, Mn, and Ni in tissue samples from 230 fish from the Rockall Trough were determined by atomic absorption spectrophotometry. Concentrations of Cu, Mn and Ni were 0.02-23 mu /g, 0.02-6.5 mu g/g and 0.02-10 mu g/g respectively. Cu appeared to selectively accumulate in liver tissues while Mn accumulated in gill tissues. Ni was evenly distributed throughout all tissues examined. Concentrations of all three metals generally decreased with length. Inter-specific differences between teleosts were found to be related to differences in feeding behaviour. There was no apparent concentration of metals through the food chain from prey to sharks. Low concentrations of Cu, Mn and Ni were detected in the water column (Cu 86-103 ng/l, Mn < 75 ng/l, Ni 210-224 ng/l), suggesting that for sharks in the Rockall Trough, the uptake of metals from diet is of more importance than that from the water column. Metallothionein-like proteins were detected in liver samples from nine species of deep-water shark. Concentrations were similar in all species (8-10 mu g/g) and were independent of hepatic Cu and Cd. It is suggested that these proteins are involved in the homeostasis of essential trace metals.
AN: 3522557
672 of 1521
TI: Deposition and fate of trace metals in our environment. Symposium proceedings. Held in Philadelphia, Pennsylvania on October 8, 1991
AU: Verry,-E.S.; Vermette,-S.J.
CA: North Cent. Forest Experiment Stn., St. Paul, MN (USA)
SO: GEN.-TECH.-REP.-USDA-FOR.-SERV.-N.-CENT.-FOR.-EXP.-STN. 1992 174 pp
RN: FSGTR-NC-150 (FSGTRNC150)
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: On October 8, 1991, in Philadelphia, the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) Technical Committee hosted a symposium on the deposition and fate of trace metals in the environment. Fourteen papers were prepared by 37 authors with a breadth of experience in trace metal ecology over the last decade. The proceedings are meant to inform the members of the analytic and collection methods for trace metals in precipitation, and the processing of trace metals in the landscape and its biota. It is a solid review of trace metals designed to facilitate an informed discussion about the addition of trace metals to the NADP/NTN network.
AN: 3522519
673 of 1521
TI: An empirical analysis of the strength of phytoplankton-dimethylsulfide-cloud-climate feedback cycle
AU: Lawrence,-M.G.
AF: Max-Planck-Inst. Chem., Mainz, FRG
SO: J.-GEOPHYS.-RES.-D-ATOMS. 1993 vol. 98, no. D11, pp. 20663-20673
LA: English
ER: M (Marine)
AB: The possible influence of the marine biogeochemical sulfur cycle on the global climate has been a topic of much recent research. Based on the hypothesis that phytoplankton could affect cloud affect cloud albedo by producing dimethylsulfide, which is a precursor to aerosols and cloud condensation nuclei, and that cloud albedo could in turn affect the productivity of the phytoplankton, the presence of such a feedback cycle would have significant implications for models of global climate change. By considering available data on the relationships between individual components of the proposed feedback, an empirical model is developed of the cycle as a whole, allowing an assessment to be made of the degree to which the cycle could thermostatically regulate the climate. It is estimated that the feedback strength is about 20% (10%-50%) of that which would be necessary to completely counteract a perturbation to the global climate, such as is anticipated due to accumulation of anthropogenic greenhouse gases.
AN: 3522144
674 of 1521
TI: The distribution and biogeochemical cycling of mercury in the Equatorial Pacific Ocean
AU: Mason,-R.P.; Fitzgerald,-W.F.
AF: Ralph Parsons Lab., 48-108, MIT, Cambridge, MA 02139, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 9, pp. 1897-1924
LA: English
ER: M (Marine)
AB: The ocean is an important part of the global mercury (Hg) cycle, both as a source and sink for atmospheric Hg. This investigation was initiated to study the speciation and distribution of Hg in the equatorial Pacific Ocean. Monomethylmercury (MMHg) and dimethylmercury (DMHg) were found principally in the low oxygen sub-thermocline region, while elemental Hg (Hg super(o)) was found throughout the upper ocean. Flux calculations and modelling studies suggest that DMHg and MMHg are formed from reactive Hg (Hg sub(R)) primarily in the low oxygen region. Particulate dissolution is the major source of Hg to the low oxygen zone. DMHg probably decomposes into MMHg, and MMHg is further demethylated to Hg super(o). In the mixed layer, Hg super(o) is also formed via direct reduction of Hg sub(R). This investigation provides evidence that the rate of supply of Hg sub(R) controls the rate of formation of methylated Hg species and Hg super(o), and that competition between these processes determines the speciation and distribution of Hg in the upper ocean of the equatorial Pacific.
AN: 3520083
675 of 1521
TI: Application of a generalized scavenging model to time series super(234)Th and particle data obtained during the JGOFS North Atlantic Bloom Experiment
AU: Clegg,-S.L.; Whitfield,-M.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP. 1993 vol. 40, no. 8, pp. 1529-1545
LA: English
ER: M (Marine)
AB: Primary production, particle concentration and flux data, obtained as part of the JGOFS North Atlantic Bloom Experiment, have been used to construct a self consistent, time dependent, particle cycle model for the upper water column for the period 25 April-30 May 1989. Daily super(234)Th concentrations and fluxes are modelled over the course of the bloom, and the results compared with available data. Use of a single pseudo-first-order rate constant k sub(1)' for the adsorption of super(234)Th onto particulate material in the model gives satisfactory agreement with measured super(234)Th profiles. Modelled concentrations of super(234)Th on large, sinking particles--which must be known in order to calculate particle fluxes from super(234)Th disequilibrium-are predicted well by the model. The results also suggest that particle fluxes determined from sediment traps may be systematically low.
AN: 3519918
676 of 1521
TI: Nature, mass and preferential sites of coarse woody debris deposits in the lower Ain valley (Mollon Reach), France
AU: Piegay,-H.
AF: Cent. Rech. Geogr. et Amenage., Univ. Jean Moulin-Lyon 3, et URA 260 CNRS, 74 Rue Pasteur, BP0638, 69239 Lyon Cedex 02, France
SO: REGUL.-RIVERS:-RES.-MANAGE. 1993 vol. 8, no. 4, pp. 359-372
LA: English
ER: F (Freshwater)
AB: Coarse woody debris (CWD) has been examined in a section of the Ain, a sixth order piedmont river with an actively meandering channel and a wooded floodplain. The spatial distribution of CWD, its mass and forms of accumulation are controlled by the hydrodynamics and the retention capacity of the forest. A typology shows the relative importance of woody debris in the mosaic of patches and the essential role of the ecotonal zones. The mass of debris varies from 0.001 t/ha to more than 200 t/ha, but is lower than those observed in certain American rivers. Most of the material is deposited in the margins and forms a narrow debris line. The restocking in woody debris is recent in Europe and tends to diversify the environment. This affects the researcher and the planner. The first considers this transit of material as a useful hydromorphodynamic and biodynamic tool which is easy to evaluate, and the second considers it as a restoring and generative vector, the ecological functions of which are recognized. Its effect is stronger today as the watershed area tends to be subjected to a decrease in agricultural activity.
AN: 3519549
677 of 1521
TI: A simple heuristic model of nutrient cycling in an estuary
AU: Kimmerer,-W.J.; Smith,-S.V.; Hollibaugh,-J.T.
AF: BioSystems Analysis Inc., 3152 Paradise Dr., Tiburon, CA 94920, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1993 vol. 37, no. 2, pp. 145-159
LA: English
ER: B (Brackish)
AB: Three decades of discussion and study have not resolved the apparent discrepancy between N-limitation of primary production and the ability of marine ecosystems to fix N. We use a simple model as a heuristic tool to examine controls on nutrient cycling in a shallow estuary, with Tomales Bay, California as the prototype. The model is a steady-state, one-box model with inputs and losses of nutrients and organic matter, and terms representing N-fixation and denitrification. The physical description of the system is deliberately kept simple to permit a focus on the key biogeochemical reactions. Growth of autotrophs in the model can be limited either by dissolved inorganic nitrogen (DIN) or dissolved inorganic phosphorus (DIP). Nitrogen-fixation is controlled by the availability of DIP or limited by excess amounts of DIN. Model results demonstrate that, for a system with a long residence time, autotroph biomass and total organic matter are controlled primarily by the rate of delivery of P to the system, either as DIP or in organic matter. Increasing the delivery rate of DIN raises autotroph biomass slightly but has little effect on total organic matter. This is because the rates of input of P as DIP or organic matter control the N-fixation rate, and denitrification limits the build-up of DIN in the system. Thus, denitrification and N-fixation act as opposing negative feedbacks, insuring that the supply of N remains roughly commensurate with that of P. When exchange with the ocean is increased, reducing residence time, the relative importance of DIN input increases relative to that of DIP.
AN: 3518700
678 of 1521
TI: Past and present cycle of carbon on our planet
AU: Schlegel,-H.G.
AF: Inst. Mikrobiol., Georg-August-Univ., Grisebachstr. 8, W-3400 Goettingen, FRG
SO: FEMS-MICROBIOL.-REV. 1992 vol. 103, no. 2-4, pp. 347-354
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AN: 3518691
679 of 1521
TI: Land and water interface zones
AU: Downing,-J.P.; Meybeck,-M.; Orr,-J.C.; Twilley,-R.R.; Scharpenseel,-H.-W.
AF: Pac. Northwest Lab., Mar. Sci. Lab., 1529 W. Sequim Bay Road, Sequim, WA 98382, USA
CO: Int. Workshop on Terrestrial Biospheric Carbon Fluxes: Quantification of Sinks and Sources of CO sub(2), Bad Harzburg (FRG), 1-5 Mar 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1993 vol. 70, no. 1-4, pp. 123-137
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: This paper reports analyses of C pools and fluxes in land-water interface zones completed at the International Workshop: Terrestrial Biospheric Carbon Fluxes; Quantification of Sinks and Sources of CO sub(2) (Bad Harzburg, Germany, March 1-5, 1993). The objective was to determine the role of these zones as global sinks of atmospheric CO sub(2) as part of a larger effort to quantify global C sinks and sources in the past (ca. 1850), the present, and the foreseeable future (ca. 2050). Assuming the world population doubles by the year 2050, storage of atmospheric C in reservoirs will also double, as will river loads of atmospheric C and nutrients. It is estimated that C sinks in temperate and boreal wetlands have decreased by about 50%, from 0.2 to 0.1 Gt C/yr, since 1850. The total decrease for wetlands may be considerably larger when tropical wetlands are taken into account, however, the area and C density of tropical wetlands are not well known at this time. Changes in cultivation practices and improved sampling of methaneogenesis have caused estimates of CH sub(4) emissions from ricelands to drop substantially from 150 to 60 Tg yr super(-1). Even with doubled N and P loads, rivers are unlikely to fertilize more than about 20% of the new primary production in the coastal ocean. The source of C for this new production may not be the atmosphere, however, because the coastal ocean exchanges large quantities of DIC with the open ocean. Until the C fluxes from air-sea exchange of CO sub(2) and DIC are better quantified, the C-sink potential of the coastal ocean will remain a major uncertainty in the global C cycle. Analysis of model simulations of oceanic C uptake reconfirmed that the open ocean appears to take up about 2.0 Gt C/yr from the atmosphere and that model estimates are in better accord now, plus or minus 0.5 Gt C/yr, than ever before.
AN: 3518538
680 of 1521
TI: Modification of the biogeochemical cycle of silica with eutrophication
AU: Conley,-D.J.; Schelske,-C.L.; Stoermer,-E.F.
AF: Horn Point Environ. Lab. Cent. Environ. and Estuar. Stud., Univ. Maryland Syst., P.O. Box 775, Cambridge, MD 21613, USA
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 101, no. 1-2, pp. 179-192
LA: English
ER: M (Marine); F (Freshwater)
AB: The response of aquatic systems to additions of N and P is generally to increase algal biomass. The partitioning of these nutrients into different functional groups of autotrophic organisms is dependent upon both intrinsic and extrinsic factors. A common response to nutrient loading in northern temperate aquatic ecosystems is an increase in diatom biomass. Because nutrient enrichment generally leads to increases in water column concentrations of total N and total P (and not Si) such nutrient loading can lead to transient nutrient limitation of diatom biomass due to lack of dissolved silicate (DSi). Increased production of diatom biomass can lead to an increased accumulation of biogenic silica in sediments, ultimately resulting in a decline in the water column reservoir of DSi. Such biogeochemical changes in the silica cycle induced by eutrophication were first reported for the North American Laurentian Great Lakes. However, these changes are not a regional problem confined to the Great Lakes, but occur in many freshwater and marine systems throughout the world. Here we summarize the effects of anthropogenic modification of silica biogeochemical cycles for the North American Laurentian Great Lakes, describe some of the biogeochemical changes occurring in other systems, and discuss some of the ecological implications of a reduction in water column DSi concentrations, including changes in species composition, as DSi concentrations become limiting to diatom growth and biomass, changes in food web dynamics, and altered nutrient-recycling processes.
AN: 3517119
681 of 1521
TI: Design and application of rRNA-targeted oligonucleotide probes for the dissimilatory iron- and manganese-reducing bacterium Shewanella putrefaciens
AU: DiChristina,-T.J.; DeLong,-E.F.
AF: Biol. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1993 vol. 59, no. 12, pp. 4152-4160
LA: English
ER: F (Freshwater)
AB: A 16S rRNA-targeted oligonucleotide probe specific for the iron (Fe super(3+))- and manganese (Mn super(4+))-reducing bacterium Shewanella putrefaciens was constructed and tested in both laboratory- and field-based hybridization experiments. The radioactively labeled probe was used to detect S. putrefaciens in field samples collected from the water column and sediments of Oneida Lake in New York and its major southern tributary, Chittenango Creek. S. putrefaciens was quantified by (i) hybridization of the probe to bulk DNA extracted from field samples and normalization of the S. putrefaciens-specific rRNA to total eubacterial rRNA, (ii) a colony-based probe hybridization assay, and (iii) a colony-based biochemical assay which detected the formation of iron sulfide precipitates on triple-sugar iron agar. The results of field applications indicated that the three detection methods were comparable in sensitivity for detecting S. putrefaciens in water column and sediment samples. S. putrefaciens rRNA was detected in the surficial layers of the lake and creek sediments, but the levels of S. putrefaciens rRNA were below the detection limits in the lake and creek water samples. The highest concentrations of S. putrefaciens rRNA, corresponding to approximately 2% of the total eubacterial rRNA, were detected in the surficial sediments of Chittenango Creek and at a midlake site where the Oneida Lake floor is covered by a high concentration of ferromanganese nodules. This finding supports the hypothesis that metal-reducing bacteria such as S. putrefaciens are important components in the overall biogeochemical cycling of iron, manganese and other elements in seasonally anoxic freshwater basins.
AN: 3516514
682 of 1521
TI: On the distribution of dissolved hydrocarbons in natural water
AU: Yunker,-M.B.; Cretney,-W.J.; Fowler,-B.R.; Macdonald,-R.W.; McLaughlin,-F.A.; Whitehouse,-B.G.
AF: Royal Roads Military Coll., FMO, Victoria, BC V0S 1B0, Canada
SO: ORG.-GEOCHEM. 1991 vol. 17, no. 3, pp. 301-307
LA: English
ER: F (Freshwater)
AB: The identity and form of dissolved organic matter in rivers and oceans are fundamental to the biogeochemical cycle of carbon. In particular, understanding the phase distribution of hydrocarbon compounds is a prerequisite to predicting the transfer between phases and the impact of anthropogenic inputs of fossil fuels to the aquatic environment. After rigorous blank-correction of each individual hydrocarbon component of dissolved and particulate hydrocarbon samples from the Mackenzie River, we obtained dissolved hydrocarbon measurements that were unquestionably above the mean blank. Equivalence of the dissolved and particulate hydrocarbon compositions indicates that the two fractions are coupled or at equilibrium in natural waters. Changes in individual hydrocarbon concentrations with sample volume suggest that the dissolved hydrocarbons may be distributed fractally in water.
AN: 3515198
683 of 1521
TI: Genetic analysis of the marine manganese-oxidizing Bacillus sp. strain SG-1: Protoplast transformation, Tn917 mutagenesis, and identification of chromosomal loci involved in manganese oxidation
AU: Van-Waasbergen,-L.G.; Hoch,-J.A.; Tebo,-B.M.*
AF: Mar. Biol. Res. Div., Scripps Inst. Oceanogr., Univ. California-San Diego, La Jolla, CA 92093, USA
SO: J.-BACTERIOL. 1993 vol. 175, no. 23, pp. 7594-7603
LA: English
ER: M (Marine)
AB: Mature spores of the marine Bacillus sp. strain SG-1 bind and oxidize manganese(II), thereby becoming encrusted with a manganese(IV) oxide. Both the function and mechanism of this oxidation are unknown, although evidence suggests that spore coat proteins are involved. To further study this phenomenon, methods of genetic analysis were developed for SG-1. By a modified protoplast transformation procedure, SG-1 was transformed ( similar to 100 transformants per mu g of DNA) with several different plasmids of gram-positive origin. Transposon Tn917, delivered on the temperature-sensitive plasmid pLTV1, was used to generate mutants of SG-1. Conditions were established that allowed 98% plasmid loss and insertions to be recovered at a frequency of 10 super(-3). Each mutant was found to be the result of a single insertion event. Restriction analysis of 27 mutants that do not oxidize manganese but still sporulate localized 17 of the insertions within two regions of the chromosome (termed Mnx regions), and a physical map of these regions was generated. Analysis of 18 transposon integrants in which manganese oxidation was unaffected revealed random transposon integration, with none of their insertions mapping within the Mnx regions. The Mnx regions were cloned from wild-type SG-1, and the largest region, carried on the lactococcal plasmid pGK13, was used to complement in trans one of the nonoxidizing mutants. The results demonstrate that the Mnx regions encode factors that are required for the oxidation of manganese, and this represents the first report identifying genes involved in bacterial manganese oxidation.
AN: 3514455
684 of 1521
TI: Nutrient release from crayfish, and its potential impact on primary production in lakes
AU: Hessen,-D.O.; Kristiansen,-G.; Skurdal,-J.
AF: Norwegian Inst. Water Res., Box 69 Korsvoll, N-0808 Oslo 8, Norway
CO: 9. Int. Symp. of Astacology, Reading, Barkshire (UK), 5-10 Apr 1992
SO: FRESHWATER-CRAYFISH-IX. Holdich,-D.M.;Warner,-G.F.-eds. LAFAYETTE,-LA-USA UNIVERSITY-OF-SOUTHWESTERN-LOUISIANA 1993 pp. 311-317
LA: English
ER: F (Freshwater)
AB: The potential effect of nitrogen (N) and phosphorus (P) release from noble crayfish, Astacus astacus (L.), on phytoplankton production was assessed by combining experimental data on total release and crayfish density calculations in mesotrophic Lake Steinsfjorden. While the crayfish has a substantial release of dissolved nitrogen, there is a low specific release of P compared to other aquatic organisms. The maximum potential phytoplankton yield sustained by nutrient release from crayfish in this lake would not exceed an equivalent of 1.4 mg C m super(-2)/d, which was less than 1% of measured primary production of the lake. It may be concluded that zooplankton and fish are far more important for the nutrient cycling of the lake. While these pelagic components of the aquatic food web are important both as consumers and remineralizers, the role of crayfish is primarily to process dead organic matter.
AN: 3514349
685 of 1521
TI: Digestive enzyme activity as a quantitative measure of protistan grazing: The acid lysozyme assay for bacterivory
AU: Gonzalez,-J.M.; Sherr,-B.F.; Sherr,-E.B.
AF: Japan Mar. Sci. and Technol. Cent., 2-15 Natsushima-cho, Yokosuka 237, Japan
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 100, no. 1-2, pp. 197-206
NT: Bibliogr.: 50 ref.
LA: English
ER: M (Marine)
AB: Lysozyme specifically degrades peptidoglycan, a major structural component of prokaryotic cell walls. The basis of the method is determination of lysozyme activity present in protistan food vacuoles by using a fluorochrome-linked artificial substrate, 4-methylumbelliferyl beta -D-N,N',N"-triacetylchitotriose (MUF- (GlcNAc) sub(3)) as an analogue of peptidoglycan. Measurement of rate of MUF cleavage from the substrate in sonicated samples at acid pH (4.5) distinguishes activity of digestive enzymes present in protistan food vacuoles from extracellular or intracytoplasmic lysozyme activity. Acid lysozyme activity was calibrated against rate of bacterivory estimated using the fluorescently labeled bacteria (FLB) uptake method. Results from the 2 methods were significantly correlated (r super(2) = 0.98) for both cultures of bacterivorous protists and for estuarine and nearshore seawater samples, over a wide range of rates of bacterivory (10 super(3) to 10 super(6) bacteria ml super(-1) h super(-1)). The relation between the 2 variables determined from water samples taken in open North Pacific gyre water had a higher slope compared to that of the other samples.
AN: 3512333
686 of 1521
TI: An introduction to the biogeochemical cycling of calcium and substitutive strontium in living coral reef mesocosms
AU: Lang,-G.T.
AF: Environ. Sci., P.O. Box 409, Cochranton, PA 16314, USA
SO: ZOO-BIOL. 1993 vol. 12, no. 5, pp. 425-433
NT: Special issue: Aquariums.
LA: English
ER: M (Marine)
AB: The coral reef mesocosms designed by the Smithsonian Institution's Dr. Walter Adey, his Marine System Laboratory personnel, and staff members of the Pittsburgh Aqua-Zoo simulate most of the physical, chemical, and biological parameters found in natural Caribbean coral reefs. After developing the mesocosm in Pittsburgh, an evaluation and comparison between natural reef seawater sources and closed mesocosm seawater conditions indicated that an additional parameter should be investigated. It was hypothesized that, given time, the aragonite- and calcite (CaCO sub(3) crystal forms)-producing organisms in the closed mesocosms could deplete the seawater of available Ca super(2+) and substitutive Sr super(2+). Atomic absorption spectrophotometry was utilized to determine concentrations in the seawater over time. Results showed a substantial reduction in dissolved Ca and Sr in the mesocosm after approximately two years. Dissolved aragonitic Halimeda algae parts were put into the system for replacive purposes. In terms of the biogeochemical cycling of Ca super(2+) and Sr super(2+), the coral reef mesocosm organisms behaved similarly to natural reefs, which have a constant supply of dissolved Ca super(2+) and Sr super(2+). Further research utilizing radiolabeled sources of Ca super(2+), Sr super(2+), and Mg super(2+), in conjunction with in vivo scanning electron microscopy (SEM) and growth increment studies, are recommended for determining the exact biogeochemical pathways for these elements in coral reefs, and to quantify growth parameters.
AN: 3512258
687 of 1521
TI: Accord between ocean models predicting uptake of anthropogenic CO sub(2)
AU: Orr,-J.C.
AF: Lab. Modelisation Climat. Environ., DSM/CEN Saclay/CEA, L'Orme Merisiers, Bat. 709, F-91191 Gif-sur-Yvette, France
CO: Int. Workshop on Terrestrial Biospheric Carbon Fluxes: Quantification of Sinks and Sources of CO sub(2), Bad Harzburg (FRG), 1-5 Mar 1993
SO: WATER,-AIR,-SOIL-POLLUT. 1993 vol. 70, no. 1-4, pp. 465-481
LA: English
ER: M (Marine)
AB: Models of the ocean provide the best estimate of how much anthropogenic CO sub(2) the ocean can and will absorb. Yet their agreement is only within 40% as characterized by the range of 2.0 plus or minus 0.8 Gt C/yr computed by the Intergovernmental Panel on Climate Change (IPCC) in 1990 from four model estimates. Since then, one of the former results has been updated and two new model estimates have become available. In a reassessment, now with six ocean models and concern for individual model uncertainties, this study found a narrower range of 2.0 plus or minus 0.5 Gt C/yr (38% less than the former uncertainty). Less uncertainty for oceanic uptake of anthropogenic CO sub(2), means greater certainty for two combined terms in the budget for the global carbon cycle. First the uncertainty of the combined atmosphere plus ocean sink is also nearly halved (now at plus or minus 0.5 Gt C/yr for 1980-1989). Second, the uncertainty of the imbalance term (or missing sink) is reduced, but only slightly because most of its large uncertainty remains associated with the difficulty in precisely quantifying deforestation and land use change.
AN: 3509485
688 of 1521
TI: Benthic bacterial production and nutrient sediment-water exchange in sandy North Sea sediments
AU: Van-Duyl,-F.C.; Van-Raaphorst,-W.; Kop,-A.J.
AF: Netherlands Inst. Sea Res. (NIOZ), P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 100, no. 1-2, pp. 85-95
NT: Bibliogr.: 69 ref.
LA: English
ER: M (Marine)
AB: The relationship between benthic bacterial production and biomass and sediment-water exchange rates of inorganic nutrients was examined in the North Sea (Dogger Bank region), in summer. The sediments were sandy, poor in organic matter and with low buffering capacities for nutrients. Fluxes of dissolved inorganic N (DIN) and P (DIP) across the sediment-water interface were measured using undisturbed sediment cores. Bacterial production ( super(3)H-thymidine incorporation method) in the sediment surface layer and bacterial biomass were analysed in the same sediment. By comparison of the benthic activities at 13 stations we assessed significant negative relations between bacterial production and sediment-water fluxes of nutrients. With increasing bacterial production the net efflux of DIN and DIP decreased. Bacterial production was significantly related to bacterial biomass and bacterial biomass was significantly related to chlorophyll a and pheopigment in the sediment, suggesting that enhanced bacterial production rates were associated with input of organic carbon.
AN: 3507956
689 of 1521
TI: New and regenerated production in relation to the microbial loop in the NW Mediterranean Sea
AU: Selmer,-J.-S.; Ferrier-Pages,-C.; Cellario,-C.; Rassoulzadegan,-F.
AF: Dep. Gen. and Mar. Microbiol., Univ. Goeteborg, Carl Skottsbergs Gata 22, S-413 19 Goeteborg, Sweden
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 100, no. 1-2, pp. 71-83
NT: Bibliogr.: 71 ref.
LA: English
ER: M (Marine)
AB: Nitrogen transformations were investigated in the Bay of Villefranche-sur-Mer, on the south coast of France, during autumn 1990 and spring 1991, using super(15)N-isotope techniques on size-fractionated sea water samples. Besides measuring uptake of ammonium and nitrate, and ammonium regeneration, the biological composition in 4 size fractions (< 1 mu m, <10 mu m, <100 mu m and unfractionated water) was determined. The plankton was dominated by pico- and nanoplankton, of which the cyanobacteria and nanoflagellates dominated the autotrophs. Heterotrophic bacteria constituted 70 and 30% of the <1 mu m and <10 mu m fractions, respectively. During spring, ammonium uptake rates were low and nitrate uptake rates often negligible, resulting in a total dominance (98 to 100%) of regenerated production. In autumn, however, nitrate uptake rates were higher, with new production amounting to 34%. The regenerated production was mostly accomplished by pico- and nanoplankton, especially cyanobacteria and autotrophic nanoflagellates, but also heterotrophic bacteria.
AN: 3507955
690 of 1521
TI: Production of organic and inorganic carbon within a large-scale coccolithophore bloom in the Northeast Atlantic Ocean
AU: Fernandez,-E.; Boyd,-P.; Holligan,-P.M.; Harbour,-D.S.
AF: Plymouth Mar. Lab., Prospect Pl., West Hoe, Plymouth PL1 3DH, UK
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 97, no. 3, pp. 271-285
NT: Bibliogr: 52 ref.
LA: English
ER: M (Marine)
AB: An extension bloom (250,000 km super(2)) of the coccolithophore Emiliania huxleyi developed in the northeast Atlantic in Jun 1991. At the time of the observations in late Jun, the centre of the bloom was characterised by low concentrations of chlorophyll a (< 1 mg m super(-3)) and particulate organic carbon (< 200 mg m super(-3)) and high particulate inorganic carbon (PIC) (> 300 mg m super(-3)) values. Photosynthesis-irradiance experiments carried out along the cruise track showed the existence of a negative exponential relationship between assimilation number (P super(B) sub(m) sub(a) sub(x)) and PIC. Significant rates of inorganic carbon incorporation were only measurable in surface waters at the periphery of the bloom and in subsurface waters north of 61 degree N. Calcification rates of up to 1.5 mg C m super(-3) h super(-1) were measured. In general, a direct relationship was found between calcification rates and P super(B) sub(m) sub(a) sub(x) or chlorophyll a-normalized photosynthesis. Calcification-irradiance curves revealed that significant amounts of carbon were incorporated into coccoliths in darkness and also that, on some occasions, calcification in subsurface populations saturated at higher irradiances than in surface ones. An empirical model based on the biomass of E. husleyi and Coccolithus pelagicus and the beam attenuation coefficient accounted for a large proportion (> 70%) of the variability in surface rates of calcification. Estimates of calcification rates derived from the model are consistent with previously reported data and compatible with the measured stocks of PIC and with the duration of the bloom as revealed by satellite imagery.
AN: 3507769
691 of 1521
TI: Project POSEIDON, the NODC on-line database
AU: Topoly,-P.J.
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 p. 393
NT: Summary only.
LA: English
ER: M (Marine)
AB: The U.S. National Oceanographic Data Center (NODC) has under development a relational database system for in-situ marine biogeochemical parameters. The system is intended to replace the mainframe-oriented NODC master files. The first phase of this development, Project POSEIDON, is being undertaken to demonstrate the capabilities and possibilities of such a system. POSEIDON has been developed using a client-server architecture consisting of DEX VAX cluster and a Teradata 700 data base engine. The relational model used to store, manage, and access data is a simple approach keyed to individual marine data parameters. Each parameter is keyed or linked to other parameters by a complex, yet straightforward, set of metadata. The POSEIDON database is not being implemented as an application, but rather as a fast powerful data supplier to other applications. A graphical user interface system, PEGASUS, is the link between the database and the user. This interface is being developed in three phases: an internal LAN version for NODC data management; a network version for Internet and dial-in access; and a stand-alone version for personal computers and workstations. The latter implementation, coupled with a POSEIDON database on a CD-ROM, will provide the climate researcher with a powerful, yet simple desktop tool. Beta testing of PEGASUS will begin in the Spring of 1992.
AN: 3506668
692 of 1521
TI: Automated in situ observations of upper ocean biogeochemistry, bio-optics, and physics and their potential use for global studies
AU: Dickey,-T.D.; Granata,-T.C.; Taupier-Letage,-I.
AF: Ocean Phys. Group, Univ. South. California, Dep. Geol. Sci., SCI 283, Los Angeles, CA 90089-0740, USA
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 317-355
LA: English
ER: M (Marine)
AB: The processes controlling the flux of carbon in the upper ocean have dynamic ranges in space and time of at least nine orders of magnitude. These processes depend on a broad suite of inter-related biogeochemical, bio-optical, and physical variables. These variables should be sampled on scales matching the relevant phenomena. Traditional ship-based sampling, while critical for detailed and more comprehensive observations, can span only limited portions of these ranges because of logistical and financial constraints. Further, remote observations from satellite platforms enable broad horizontal coverage which is restricted to the upper few meters of the ocean. For these main reasons, automated subsurface measurement systems are important for the fulfillment of research goals related to the regional and global estimation and modeling of time varying biogeochemical fluxes. Within the past few years, new sensors and systems capable of autonomously measuring several of the critical variables have been developed. The platforms for deploying these systems now include moorings and drifters and it is likely that autonomous underwater vehicles (AUV's) will become available for use in the future. Each of these platforms satisfies particular sampling needs and can be used to complement both shipboard and satellite observations. In this review, 1) sampling considerations are summarized, 2) examples of data obtained from some of the existing automated in situ sampling systems are highlighted, 3) future sensors and systems are discussed, 4) data management issues for present and future automated systems are considered, and 5) the status of near real-time data telemetry are outlined.
AN: 3506614
693 of 1521
TI: Ocean time-series near Bermuda: Hydrostation S and the U.S. JGOFS Bermuda Atlantic time-series study
AU: Michaels,-A.F.; Knap,-A.H.
AF: Bermuda Biol. Stn., Ferry Reach, St. Georges, Bermuda
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 295-316
LA: English
ER: M (Marine)
AB: Bermuda is the site of two ocean time-series programs. At Hydrostation S, the ongoing biweekly profiles of temperature, salinity and oxygen now span 37 years. This is one of the longest open-ocean time-series datasets and provides a view of decadal scale variability in ocean processes. In 1988, the U.S. JGOFS Bermuda Atlantic Time-series Study began a wide range of measurements at a frequency of 14-18 cruises each year to understand temporal variability in ocean biogeochemistry. On each cruise, the data range from chemical analyses of discrete water samples to data from electronic packages of hydrographic and optics sensors. In addition, a range of biological and geochemical rate measurements are conducted that integrate over time-periods of minutes to days. This sampling strategy yields a reasonable resolution of the major seasonal patterns and of decadal scale variability. The Sargasso Sea also has a variety of episodic production events on scales of days to weeks and these are only poorly resolved. In addition, there is a substantial amount of mesoscale variability in this region and some of the perceived temporal patterns are caused by the intersection of the biweekly sampling with the natural spatial variability. In the Bermuda time-series programs, the authors have added a series of additional cruises to begin to assess these other sources of variation and their impacts on the interpretation of the main time-series record. However, the adequate resolution of higher frequency temporal patterns will probably require the introduction of new sampling strategies and some emerging technologies such as biogeochemical moorings and autonomous underwater vehicles.
AN: 3506608
694 of 1521
TI: Data management for community research projects: A JGOFS case study
AU: Lowry,-R.K.
AF: Proudman Oceanogr. Lab., Bidston Obs., Bidston, Birkenhead, Merseyside L43 7RA, UK
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 251-273
LA: English
ER: M (Marine)
AB: Since the mid 1980s, much of the marine science research effort in the United Kingdom has been focused into large scale collaborative projects involving public sector laboratories and university departments, termed Community Research Projects. Two of these, the Biogeochemical Ocean Flux Study (BOFS), and the North Sea Project incorporated large scale data collection to underpin multidisciplinary modeling efforts. The challenge of providing project data sets to support the science was met by a small team within the British Oceanographic Data Centre (BODC) operating as a topical data centre. The role of the data centre was to both work up the data from the ship's sensors and to combine these data with sample measurements into on-line databases. The working up of the data was achived by a unique symbiosis between data centre staff and project scientists. The project management, programming and data processing skills of the data centre were combined with the oceanographic experience of the project communities to develop a system which has produced quality controlled, calibrated data sets from 49 research cruises in 3.5 years of operation. The data centre resources required to achieve this were modest and far outweighed by the time liberated in the scientific community by the removal of the data processing burden. However, projects covering a larger, even international scale could be successfully supported by a network of topical data centres managing online databases which are interconnected by object oriented distributed data management systems over wide area networks.
AN: 3506585
695 of 1521
TI: Data management for JGOFS: Theory and design
AU: Flierl,-G.R.; Bishop,-J.K.B.; Glover,-D.M.; Paranjpe,-S.
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 229-249
LA: English
ER: M (Marine)
AB: The Joint Global Ocean Flux Study (JGOFS), currently being organized under the auspices of the Scientific Committee for Ocean Research (SCOR), is intended to be a decade long internationally coordinated program. The main goal of JGOFS is to determine and understand on a global scale the processes controlling the time-varying fluxes of carbon and associated biogenic elements in the ocean and to evaluate the related exchanges with the atmosphere, sea floor and continental boundaries. A long-term goal of JGOFS will be to establish strategies for observating, on long time scales, changes in ocean biogeochemical cycles in relation to climate change. Participation from a large number of U.S. and foreign institutions is expected. JGOFS investigators have begun a set of time-series measurements and global surveys of a wide variety of biological, chemical and physical quantities, detailed process-oriented studies, satellite observations of ocean color and wind stress and modeling of the bio-geochemical processes. These experiments will generate data in amounts unprecedented in the biological and chemical communities; rapid and effortless of these data will be important to the success of JGOFS. The authors discuss the possibility for the user of a small computer connected to a network to be able to locate and work with data at NODC or indeed anywhere in a distributed data base without regards to its location or format.
AN: 3506576
696 of 1521
TI: The JGOFS North Atlantic Bloom Experiment: An overview
AU: Ducklow,-H.W.
AF: Horn Point Mar. Lab., Univ. Maryland, Cambridge, MD 21613, USA
CO: Ocean Climate Data Workshop, Greenbelt, MD (USA), 18-21 Feb 1992
SO: PROCEEDINGS-OF-THE-OCEAN-CLIMATE-DATA-WORKSHOP. Churgin,-J.-comp. GREENBELT,-MD-USA NASA-GODDARD-SPACE-FLIGHT-CENT. 1993 pp. 205-227
LA: English
ER: M (Marine)
AB: The North Atlantic Bloom Experiment (NABE) of the Joint Global Ocean Flux Study (JGOFS) presents a unique opportunity and challenge to the data management community because of the diversity and large size of biogeochemical data sets collected. NABE was a pilot study for JGOFS and has also served as a pilot study within the US NODC for management and archiving of the data sets. The author presents an overview to some of the scientific results of NABE, which will be published as an Introduction to a special volume of NABE results in Deep-Sea Research. An overview of NABE data management is given elsewhere in the present report. This is the first collection of papers from JGOFS. Formed as an international program in 1987, JGOFS has four principal elements: modelling and data management, multidisciplinary regional process studies, a global survey of biogeochemical properties and long-term time series observatories. In 1989-90 JGOFS conducted a pilot process study of the spring phytoplankton bloom, the North Atlantic Bloom Experiment (NABE). JGOFS decided to conduct a large scale, internationally-coordinated pilot study in the North Atlantic because of its proximity to the founding nations of the project, the size and predictability of the bloom and its fundamental impact on ocean biogeochemistry.
AN: 3506564
697 of 1521
TI: Emerging role of atmospheric nitrogen deposition in coastal eutrophication: Biogeochemical and trophic perspectives
AU: Paerl,-H.W.
AF: Inst. Mar. Sci., Univ. North Carolina, Morehead City, NC 28557, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1993 vol. 50, no. 10, pp. 2254-2269
LA: English
ER: M (Marine)
AB: Aapproximately half of the world's oceanic primary production originates in coastal waters which are often nitrogen (N) limited and sensitive to externally supplied N. Among anthropogenically generated N sources, atmospheric deposition of N (ADN) (as wet- and dryfall) contributes 10-50% of the total external N load at present (20-100 mmol N/m super(2)/yr), and this will increase. At current levels, atmospheric N inputs lead to a two- to threefold enhancement of CO sub(2) fixation and chlorophyll a production. ADN may play a central role in mediating "new" production in coastal oceans downwind of emissions. Alterations in productivity, nutrient flux, and trophic changes have recently been documented from the Baltic and North seas, the Northwest Atlantic seaboard, and the Western Mediterranean.
AN: 3506514
698 of 1521
TI: Todorokite formation in seawater by microbial mediation
AU: Takematsu,-N.; Kusakabe,-H.; Sato,-Y.; Okabe,-S.
AF: Inst. Phys. and Chem. Res., Wako-shi, Saitama 351-01, Japan
SO: J.-OCEANOGR.-SOC.-JAPAN-NIHON-KAIYO-GAKKAI 1988 vol. 44, no. 5, pp. 235-243
LA: English
ER: M (Marine)
AB: Microbial manganese oxidation in seawater was carried out in enrichment cultures which were obtained from the seawater supply system at the Marine Science Museum, Tokai University (Shimizu-shi, Japan). The manganese oxide formed was well-crystallized todorokite. The major element composition was within the range of marine manganese concretions and the O/Mn molar ratio was 1.8. The conditions for formation of manganese oxide minerals in marine environments are discussed on the basis of these results.
AN: 3506323
699 of 1521
TI: Arsenic in the sea
AU: Francesconi,-K.A.; Edmonds,-J.S.
AF: Western Australian Mar. Res. Lab., P.O. Box 20, North Beach, Western Australia 6020, Australia
SO: OCEANOGRAPHY-AND-MARINE-BIOLOGY:-AN-ANNUAL-REVIEW. Ansell,-A.D.;Gibson,-R.N.;Barnes,-M.-eds. LONDON-UK UCL-PRESS 1993 vol. 31 vol. 31, pp. 111-151
ST: OCEANOGR.-MAR.-BIOL.-ANNU.-REV. vol. 31
LA: English
ER: M (Marine)
AB: An historical account of marine arsenic research and current views on the biotransformation of arsenic in marine ecosystem is presented. Research on arsenic in marine sediments, sea water, marine algae, and marine animals is reviewed from 1900 to the present. Emphasis is placed on work examining the chemical form of arsenic in the various marine compartments. In marine ecosystems arsenic can occur in many different chemical forms, including arsenite and arsenate, methylarsonic and dimethylarsinic acids, trimethylarsine oxide, tetramethylarsonium ion, arsenobetaine, and a number of arsenic-containing ribosides. The biotransformation of these marine arsenicals is discussed, in particular the biogenesis of arsenic-containing ribosides in marine algae and the origin of arsenobetaine in marine animals are considered.
AN: 3506280
700 of 1521
TI: Use of perfused cores for evaluating extracellular enzyme activity in stream-bed sediments
AU: Marxsen,-J.; Fiebig,-D.M.
AF: Limnol. Flussstn., Max-Planck-Inst. Limnol., P.O. Box 260, D-36105 Schlitz, FRG
SO: FEMS-MICROBIOL.-ECOL. 1993 vol. 13, no. 1, pp. 1-12
LA: English
ER: F (Freshwater)
AB: beta -glucosidase activity was investigated in stream-bed sediments using 4-methylumbelliferyl- beta -D-glucopyranoside (MUF- beta -Glc) as a model substrate. In a perfused core technique, water containing MUF- beta -Glc was perfused up through sediment cores. beta -glucosidase activity was quantified from the release of fluorescent MUF in water discharged from the cores. At low rates of perfusion, maximum beta -glucosidase activity (V sub(max)) in perfused sediments was similar to that in suspended (unperfused) sediments. Substrate affinity (K sub(m)) was higher in the suspended sediments. V sub(max) and K sub(m) both increased when the perfusion rate was raised, although naturally-low substrate concentrations could mean that variability in perfusion rates has little effect on enzyme activity in the field. V sub(max) was uninfluenced by whether ground or stream water was perfused through the sediments, but K sub(m) was higher in cores perfused with groundwater. Increasing concentrations of glucose in the perfusion water resulted in a progressive inhibition of beta -glucosidase activity. Although natural concentrations of glucose were low, the high turnover of enzymatically-released glucose probably means that beta -glucosidase activity could be regulated by product concentration.
AN: 3505404
701 of 1521
TI: Seasonal variation in net benthic C-mineralization in a shallow estuary
AU: Therkildsen,-M.S.; Lomstein,-B.A.
AF: Dep. Microbial Ecol., Inst. Biol. Sci., Univ. Aarhus, DK-8000 Aarhus-C, Denmark
SO: FEMS-MICROBIOL.-ECOL. 1993 vol. 12, no. 2, pp. 131-142
LA: English
ER: B (Brackish)
AB: Seasonal changes in net benthic C-mineralization were measured as sediment O sub(2) uptake, as well as sigma CO sub(2) flux from the sediment to the water column. Oxygen uptake varied between 26 and 181 mmol m super(-2) d super(-1) through the year, and sigma CO sub(2) efflux varied between 17 and 132 mmol m super(-2) d super(-1). Both parameters were related to temperature, and the Q sub(10) for O sub(2) uptake and sigma CO sub(2) efflux were 2.5 and 2.0, respectively. The sigma CO sub(2)/O sub(2) ratio varied between 0.8 and 1.0 during most of the year. The sigma CO sub(2)/O sub(2) ratio was, however, less than 0.8 in late summer and autumn, which might be due to reoxidation of accumulated reduced sulfur compounds and carbonate precipitation. Calcium carbonate deposition by molluscs seemed quantitatively important for the sigma CO sub(2) efflux in September 1990 and August 1991. The sigma CO sub(2)/O sub(2) ratio reached a maximum of 1.3 in mid-April during decomposition of benthic and sedimented microalgae. On an annual basis, all the oxidants which were reduced during anaerobic mineralization (e.g., Mn super(2+), Fe super(2+), HS super(-)), apparently were reoxidized by O sub(2), as illustrated by an annual sigma CO sub(2)/O sub(2) ratio of 0.8.
AN: 3505401
702 of 1521
TI: Biogeochemical cycle of mercury species in the marine environment
AU: Branica,-M.; Mikac,-N.; Kwokal,-Z.
AF: Cent. Mar. Res., "Rudjer Boskovic" Inst., Zagreb, Croatia
SO: FINAL-REPORTS-ON-RESEARCH-PROJECTS-DEALING-WITH-THE-EFFECTS-OF-POLLUTANTS-ON-MARINE-COMMUNITIES-AND-ORGANISMS.#RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-TRAITANT-DES-EFFETS-DE-POLLUANTS-SUR-LES-COMMUNAUTES-ET-LES-ORGANISMES-MARINS. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1993 no. 73 no. 73, pp. 153-173
ST: MAP-TECH.-REP.-SER. no. 73
LA: English
ER: M (Marine)
AB: Mercury distribution in 2 areas of the Eastern Adriatic was investigated. One area is unpolluted with respect to mercury (Krka river estuary and the Kornati Archipelago) and the other is seriously polluted by mercury from the chlor-alkali plant (Kastela bay). The percentages of organic mercury were: 0.5% in sediment; 4-12% in plankton; 15-66% in mussels and 47-90% in fish. Some fish species contained a very high organic mercury level confirming a successful biomagnification of mercury in this low-mercury environment. A study of the mercury speciation in estuarine water of this stratified estuary showed that in the upper low-salinity water layer the reactive mercury content varied considerably and generally corresponded to the dissolved mercury fraction. Mercury accumulation at the depth of halocline was observed. In the Kastela bay extremely high total mercury concentrations in sediment (200 mg kg super(-1) w.w), water (320 mu g dm super(-3)) and mussels (182 mg kg super(-1) w.w) sampled in front of the chlor-alkali plant decreased rapidly with increasing the distance from the pollution source. It is concluded that levels of mercury in the Mediterranean do not essentially differ from the values obtained throughout the world. The elevated mercury levels in some areas do not apply for the entire Mediterranean waters.
AN: 3505357
703 of 1521
TI: The coral reef ecosystem at Chiriatapu in South Andaman. 2. Chemical ecology and system model
AU: Mukherjee,-B.; Mehrotra,-N.P.
AF: Postgrad. Dep. Zool., Univ. Ranchi, Ranchi 834 001, India
SO: J.-MAR.-BIOL.-ASSOC.-INDIA 1992 vol. 34, no. 1-2, pp. 179-188
LA: English
ER: M (Marine)
AB: The fringing reef at Chiriatapu in South Andaman is a leeward channel reef and presents a topography which ensures substantial water residence time of about 30 days. Water from the open ocean enters the reef with moderate budgets of various chemical constituents across the reef biogeochemical gradients develop in tune with the metabolic rhythm (Photosynthesis, respiration and calcification) of the biota. Organic carbon production, respiration and calcium deposition (gross and net production as inferred from carbon dioxide utilization are 4.25 and 0.56 gC/m super(2)/d respectively, while the rate of calcium carbonate deposition is 1.3 g/m super(3)/d by the biota alter the oxygen and carbon dioxide content, as well as the salinity, together with various ionic species to produce alternate zones of varying chemical speciation. The various factors controlling the circulation pattern has been considered, and a modified mathematical model has been proposed for the ecosystem.
AN: 3504942
704 of 1521
TI: The global methane cycle
AU: Wahlen,-M.
AF: Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093, USA
SO: ANNU.-REV.-EARTH-PLANET.-SCI. 1993 vol. 21, pp. 407-426
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Methane is a radiatively and chemically important constituent of the Earth's atmosphere, and it substantially contributes to the terrestrial greenhouse effect. Atmospheric mixing ratios of methane are increasing rapidly today, and large natural fluctuations, by a factor of two, have occurred in different climatic periods in the past. Over the recent 200 years, atmospheric methane mixing ratios have increased more than a factor of two over preindustrial values due to anthropogenic influence. While the gross features of the global methane budget are known, the details about individual source strengths are still poorly understood.
AN: 3504727
705 of 1521
TI: Chitin production by crustaceans in marine ecosystems
OT: La production de chitine par les crustaces dans les ecosystemes marins
AU: Jeuniaux,-C.; Voss-Foucart,-M.-F.; Bussers,-J.C.
AF: Lab. Morphol. Systematique Ecol., Inst. Van Beneden, quai Van Beneden, 22 B-4020 Liege, Belgium
CO: 1. European Crustacean Conf., Paris (France), 31 Aug-4 Sep 1992
SO: AQUAT.-LIVING-RESOUR.-RESSOUR.-VIVANTES-AQUAT. 1993 vol. 6, no. 4, pp. 331-341
LA: English
ER: M (Marine)
AB: Chitin is synthesized by numerous animal species, either unicellular organisms or metazoans, belonging mainly to zoological groups of the Coelomate Spiralia lineage. However, the produced chitin in marine ecosystems is principally by crustaceans. A comparative study of analytical data so far available allowed calculation of chitin biomass and chitin production values in some types of marine ecosystems, and thus estimation of the quantitative importance of chitin in the biogeochemical cycles of carbon and nitrogen. The main data so far available concerns mediterranean plankton in Calvi bay (Corsica), arctic and antarctic krill, lobster population on South African coasts, and infralittoral benthic communities growing on rocky substrates on Corsica coasts. In all these case, chitin production was estimated roughly at 1g per year and per square meter of rocky substrate or sea surface. Taking into account these production values and the relative extent of the main marine ecosystems over the world, the total production of chitin due to marine crustaceans was estimated at about 2.3 billion metric tons per year.
AN: 3501287
706 of 1521
TI: Oxygen and carbon dioxide water-sediment interface in the southwest lagoon of New Caledonia: Methods and raw data
OT: Flux d'oxygene et de gaz carbonique a l'interface eau-sediment dans le lagon sud-ouest de Nouvelle-Caledonie: Methodes et recueil des donnees
AU: Garrigue,-C.; Clavier,-J.; Boucher,-G.; Gerard,-P.; Menou,-J.L.
AF: Inst. Fr. Rech. Sci. Dev. Coop., ORSTOM, B.P. A5, Noumea, New Caledonia
SO: RAPP.-SCI.-TECH.-SCI.-MER-BIOL.-MAR.-CENT.-NOUMEA-ORSTOM NOUMEA-NEW-CALEDONIA ORSTOM 1992 no. 62, 21 pp
LA: French
ER: M (Marine)
AB: Incubation chambers were used to study aerobic and anaerobic metabolism of the benthos at the water-sediment interface. Triplicate incubations were carried out in darkness during 5 hours on fourteen stations allocated on the three bottom types previously described in the lagoon. Oxygen probes were used for continuous oxygen recording. Water pH measured with glass electrodes, salinity and temperature were used in order to calculte dioxide carbon flux. Water samples were withdrawn with syringes at the beginning and at the end of each incubation for total alkalinity measurements using potentiometric titration. Calcium carbonate flux were evaluated. 15 incubations were carried out to measure chemical oxygen flux of sediment. At the end of the incubations, samples were collected in the enclosed substrate for analysis on sediment parameters (granulometry, organic matter) and living organisms (ATP, photosynthetic pigments, macrobenthos). This paper presents methods used and raw data obtained during two cruises of R.V. ALIS in the south-west lagoon of new Caledonia, from 10 to 20 December 1991 and from 6 to 9 January 1992.
AN: 3501142
707 of 1521
TI: In situ assessment of denitrification in running waters: Example of the Charente River
OT: Etude experimentale de la denitrification in situ en eaux courantes: Application a la Riviere Charente
AU: Torre,-M.; Rebillard,-J.P.; Ayphassorho,-H.; Labroue,-L.; Helmer,-C.
AF: Cent. Natl. Mach. Agric., Genie Rural Eaux Foret, Div. Qual. Eaux, B.P. 3, 33611 Gazinet Cedex, France
SO: ANN.-LIMNOL. 1992 vol. 28, no. 3, pp. 263-271
LA: French
ER: F (Freshwater)
AB: The aim of this study was to quantify the denitrification rate and to insert it in a nitrate hydrological model. The comparison of the field measurements and evaluation by calculation of the denitrification phenomenon shows that it is preferable to estimate the denitrification rate by direct titration instead of nitrogen form analysis.
AN: 3501102
708 of 1521
TI: Organic production and excretion by different phytoplankton size classes
AU: Legrand,-C.; Malinsky-Rushansky,-N.Z.
AF: Cent. Rech. Ecol. Mar. Aquacult. de l'Houmeau (CNRS-IFREMER), BP 5 F-17137, L'Houmeau, France
CO: Int. Symp. on Measurement of Primary Production from the Molecular to the Global Scale, La Rochelle (France), 21-24 Apr 1992
SO: MEASUREMENT-OF-PRIMARY-PRODUCTION-FROM-THE-MOLECULAR-TO-THE-GLOBAL-SCALE.-PROCEEDINGS-OF-A-SYMPOSIUM-HELD-IN-LA-ROCHELLE,-21-24-APRIL-1992. COPENHAGEN-DENMARK ICES 1993 vol. 197 p. 280
ST: ICES-MAR.-SCI.-SYMP. vol. 197
NT: Summary only.
LA: English
ER: M (Marine); F (Freshwater)
AB: Excretion rates of photosynthetic products by different classes of phytoplankton are difficult to compare, partly because of the different assay techniques or laboratory instruments used. The purpose of this research is to compare the carbon fluxes between nano- and pico-planktonic eukaryotic algae from salt ponds and lake water respectively, using identical techniques and laboratory equipment. Photosynthetic particulate organic carbon assimilation (POC) and excretion of dissolved organic compounds (DOC) by the algae as well as the subsequent bacterial assimilation and respiration were measured by super(14)C technique using differential filtration. The percentage of extracellular release (PER) of dissolved organic compounds was lower (3.3-5.0%) for larger algal cells than for the picoeukaryotes (10.9%). PER of a natural mixed salt pond phytoplankton population was intermediate (9.7%), while maximal values for the picoplanktonic natural freshwater fraction was 8%. Bacterial assimilation of the DOC released by the algae under these growth conditions seems to be related more to algal species than to biovolume, although there may also be an effect of the different and specific bacterial assemblages. The remineralization of the total DOC respired to CO sub(2) was higher for the freshwater (18.3%) than for the salt pond (7.3-16.3%) populations. Great variations were found in the respiration rates of natural bacteria from DOC excreted by the freshwater picoalgae (94%) and from these excreted by the nanoplanktonic salt pond algae (0-59%). Results show that bacterial assimilation and mineralization of DOC contributes actively (irrespective of phytoplankton biovolume) to the carbon flux in freshwater and in marine environments. Higher bacterial respiration rate and higher picoplankton excretion rates were observed in fresh water, suggesting a relatively higher flux of carbon by this pathway in fresh water than in salt water. Results also show that assimilation of CO sub(2) by algae, measured by the super(14)C technique, can be incorrectly evaluated if the amounts of extracellular release as well as the percentage of bacterial assimilation and mineralization are ignored.
AN: 3053679
709 of 1521
TI: The Bolin-65 Symposium
AU: Rodhe,-H.-(ed.)
CO: Bolin-65 Symp., Stockholm (Sweden), 20-23 May 1990
SO: TELLUS-A-B 1991 vol. 43A-B, no. 4, 203 pp
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The papers in this special joint issue of Tellus A and B were presented at a Symposium in honour of Professor Bert Bolin on the occasion of his 65th birthday and retirement from Stockholm University. 50 of Bert Bolin's colleagues and collaborators over the years met at Oersundsbro outside Stockholm to discuss past, present and possible future developments in our understanding of the atmospheric system. The theme of the Symposium was "Atmospheric Sciences--Quo Vadimus?". This theme is a broad one including such questions as Where are we?, Where did we come from?, Where are we going? and What are the issues for the future? The presentations and discussions were organized in the following five sessions: General Circulation of the Atmosphere, Numerical Weather Prediction, Ocean Modelling, Biogeochemical Cycles, and Global Change. These topics not only cover a wide range of issues in atmospheric science, but they also show the development in Bert Bolin's scientific research interests. The very wide definition of atmospheric science, including parts of oceanography and biology/ecology, is a characteristic feature of Bert's scientific thinking: to integrate physical, chemical and biological processes in the environment into a holistic picture of the whole climate system, including the cycling of energy, water and other substances.
AN: 3052628
710 of 1521
TI: Terrestrial biogeochemical cycles: Global interactions with the atmosphere and hydrology
AU: Schimel,-D.S.; Kittel,-T.G.F.; Parton,-W.J.
AF: Resour. Ecol. Lab., Colorado State Univ., Fort Collins, CO 80523, USA
CO: Bolin-65 Symp., Stockholm (Sweden), 20-23 May 1990
SO: THE-BOLIN-65-SYMPOSIUM. Rodhe,-H.-ed. 1991 vol. 43A-B, no. 4 pp. 188-203
ST: TELLUS-A-B vol. 43A-B, no. 4
LA: English
ER: F (Freshwater)
AB: Ecosystem scientists have developed a body of theory to predict the behavior of biogeochemical cycles when exchanges with other ecosystems are small or prescribed. Recent environmental changes make it clear that linkages between ecosystems via atmospheric and hydrological transport have large effects on ecosystem dynamics when considered over time periods of a decade to a century, time scales relevant to contemporary humankind. Our ability to predict behavior of ecosystems coupled by transport is limited by our ability (1) to extrapolate biotic function to large spatial scales and (2) to measure and model transport. We review developments in ecosystem theory, remote sensing, and geographic information systems (GIS) that support new efforts in spatial modeling. A paradigm has emerged to predict behavior of ecosystems based on understanding responses to multiple resources (e.g., water, nutrients, light).
AN: 3052595
711 of 1521
TI: On the control of the carbon-oxygen system
AU: Walin,-G.
AF: Dep. Oceanogr., Univ. Gothenburg, Box 4038, S-40040 Gothenburg, Sweden
CO: Bolin-65 Symp., Stockholm (Sweden), 20-23 May 1990
SO: THE-BOLIN-65-SYMPOSIUM. Rodhe,-H.-ed. 1991 vol. 43A-B, no. 4 pp. 121-135
ST: TELLUS-A-B vol. 43A-B, no. 4
LA: English
ER: M (Marine)
AB: The dynamical aspects of the carbon-oxygen system in the ocean and atmosphere are considered. The analysis is based on the stoichiometry of the main-reactions, relevant continuity constraints and assumptions about feedback from the state of the system. It is found that silicate weathering, though necessary for the forcing of the system, may be unimportant for the control of the system. It is thus fully possible that the stability is taken care of by feedback on the burials of carbonate, reduced carbon and sulphide, which flows may have the potential to be very sensitive to modest perturbations of the state of the ocean-atmosphere system. It is show that the coupling between the carbon and oxygen cycles becomes stronger, if silicate weathering is less important for the control, which has interesting consequences. In general, the need to keep the carbon cycle balanced on the long time scale characterizing the oxygen cycle has important implications. If feed back from pCO sub(2) on silicate weathering is sufficiently weak, we thus find that a positive feedback from pO sub(2) on the rate of burial of reduced carbon may be favourable for the stability of the system, contrary to what is commonly assumed. It is discussed how the frequency of forest fire may have a key position in the control system together with the degree of oxygen depletion in oceanic deep water, since these phenomena may provide "switches" for the formation of charcoal (i.e., deposition of reduced carbon) and burial of sulfide.
AN: 3052585
712 of 1521
TI: Molecular biology in studies of oceanic primary production
AU: LaRoche,-J.; Geider,-R.J.; Falkowski,-P.G.
AF: Oceanogr. and Atmos. Sci. Div., Dep. Appl. Sci., Brookhaven Natl. Lab., Upton, NY 11973, USA
CO: Int. Symp. on Measurement of Primary Production from the Molecular to the Global Scale, La Rochelle (France), 21-24 Apr 1992
SO: MEASUREMENT-OF-PRIMARY-PRODUCTION-FROM-THE-MOLECULAR-TO-THE-GLOBAL-SCALE.-PROCEEDINGS-OF-A-SYMPOSIUM-HELD-IN-LA-ROCHELLE,-21-24-APRIL-1992. COPENHAGEN-DENMARK ICES 1993 vol. 197 pp. 42-51
ST: ICES-MAR.-SCI.-SYMP. vol. 197
LA: English
ER: M (Marine)
AB: Remote sensing and the use of moored in situ instrumentation has greatly facilitated measurements of phytoplankton chlorophyll on global scales with high temporal resolution. However, the interpretation of these measurements with respect to primary production and biogeochemical cycles requires an understanding of physiological and biochemical processes in phytoplankton. For example, the use of satellite images of surface chlorophyll to estimate primary production is often based on the functional relationship between photosynthesis and irradiance. A variety of environmental factors such as light, temperature, and nutrient availability affect the photosynthesis/irradiance (P vs I) relationship in phytoplankton. Molecular biology provides a means to study the underlying mechanisms by which the primary producers respond to variable environmental factors. The authors present three examples showing how molecular biology can potentially be used to provide basic insight into the factors controlling primary productivity. The three examples are: (1) Light intensity regulation in which an environmental cue leads to changes in gene expression. (2) Multiple probing of photosynthetic protein expressions to test and explain biophysical and photophysiological responses. (3) Expression of specific proteins induced by nutrient limitation as a potential means of identifying factors limiting photosynthesis in the sea. These examples reflect the personal research interests of the authors, and were selected as illustrations of the potential applications of molecular biology to the study of gene regulation in natural phytoplankton.
AN: 3051112
713 of 1521
TI: Remote sensing of water-column primary production
AU: Sathyendranath,-S.; Platt,-T.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, NS B3H 4J1, Canada
CO: Int. Symp. on Measurement of Primary Production from the Molecular to the Global Scale, La Rochelle (France), 21-24 Apr 1992
SO: MEASUREMENT-OF-PRIMARY-PRODUCTION-FROM-THE-MOLECULAR-TO-THE-GLOBAL-SCALE.-PROCEEDINGS-OF-A-SYMPOSIUM-HELD-IN-LA-ROCHELLE,-21-24-APRIL-1992. COPENHAGEN-DENMARK ICES 1993 vol. 197 pp. 236-243
ST: ICES-MAR.-SCI.-SYMP. vol. 197
LA: English
ER: M (Marine)
AB: Satellite observations of ocean colour at selected wavelengths have made it possible to map near-surface distribution of phytoplankton pigments at the global scale. While the advantage of remote sensing in providing synoptic coverage of large-scale surface features is incontestable, the estimation of primary production from these data requires additional information inaccessible to present-day satellite remote sensing, such as the parameters for conversion of biomass to growth rates, and the parameters describing the vertical structure of biomass. The value of remote sensing would therefore be enhanced considerably if the satellite data could be combined with in situ data to provide the missing information. Since satellite and in situ data are collected at very different time and space scales, conceptual schemes are necessary to render the two data sets compatible. The idea of bio-geochemical provinces has proved to be very useful in this context. Both empirical and analytic approaches have been used to address the problem of estimating primary production from satellite-derived biomass estimates. The various analytic models that have been proposed can be classified according to their level of complexity. In any application, a suitable model has to be selected, based on: (1) validity of the model assumptions in the particular context, (2) computational requirements, (3) availability of auxiliary data, and (4) acceptable levels of error.
AN: 3039099
714 of 1521
TI: Ecology and evolution of microbial populations for bioremediation
AU: Liu,-S.; Suflita,-J.M.
AF: Dep. Bot. Microbiol., Univ. Oklahoma, Norman, OK 73019, USA
SO: TRENDS-BIOTECHNOL. 1993 vol. 11, no. 8, pp. 344-352
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Bioremediation exploits the genetic diversity and metabolic versatility of microorganisms for the transformation of contaminants into less-harmful end-products, which are then integrated into natural biogeochemical cycles. Understanding the ecology, physiology and evolution of degradative microorganisms is critical for the successful consideration and implementation of bioremediation. This article focuses on the common ecological and evolutionary constraints that influence bioremediation processes.
AN: 3035994
715 of 1521
TI: A high-temperature catalytic oxidation method for the determination of marine dissolved organic carbon and its comparison with the UV photo-oxidation method
AU: Chen,-W.; Wangersky,-P.J.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, NS B3H 4J1, Canada
SO: MAR.-CHEM. 1993 vol. 42, no. 2, pp. 95-106
LA: English
ER: M (Marine)
AB: A modified high-temperature catalytic oxidation (HTCO) method for marine dissolved organic carbon (DOC) measurement is described. The method has a high oxidation efficiency and a precision of 1-2%. It is robust and relatively easy to perform, and hence can be used for routine analyses. Components of the system blank are determined by the use of deionized water treated by high-temperature catalysed oxidation, and the results are checked by an experiment using super(14)C. Extensive comparisons between this method and UV photo-oxidation are presented. The HTCO method consistently yields 5-60% more DOC than the UV method, with most results in the range of 10-40%. No simple explanation has been found for the differences between the two methods, as a result of the complex nature of DOC in seawater.
AN: 3035239
716 of 1521
TI: Mercury biogeochemical cycling in a stratified estuary
AU: Mason,-R.P.; Fitzgerald,-W.F.; Hurley,-J.; Hanson,-A.K.,Jr.; Donaghay,-P.L.; Sieburth,-J.M.
AF: Ralph M. Parsons Lab., Build. 48-108, MIT, Cambridge, MA 02139, USA
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 6, pp. 1227-1241
LA: English
ER: B (Brackish)
AB: Total Hg in the permanently stratified Pettaquamscutt estuary was < 25 pM throughout the water column, even in highly sulfidic bottom waters. Particulate Hg was typically > 40% of the total Hg. Reactive Hg (Hg sub(R)) was generally < 3 pM and decreased with depth, but there is Hg sub(R) even in the anoxic bottom waters. Elemental Hg (Hg super(0)) was highest in the mixed layer and below the detection limit at depth. Demethylation is not an important source of Hg super(0) in this estuary. Dimethylmercury was not detected. Monomethylmercury (MMHg) was near the detection limit in the mixed layer and increased rapidly in the low oxygen region. Dissolved MMHg correlated with bacteriochlorophyll pigments, suggesting that the microbial community plays an important role in MMHg production in this estuary. The overall distributions of dissolved and particulate Hg species result from the interaction with Fe and Mn redox cycling, particulate scavenging and sinking, and MMHg production in the pycnocline. The estimated rate of MMHg production from Hg sub(R) in the pycnocline region is 1.7%/d. Hg super(0) and MMHg are formed principally in the mixed layer and in the pycnocline region, respectively. Particulate scavenging is important, and sedimentation, methylation, and Hg super(0) production are the principal sinks for Hg sub(R).
AN: 3035029
717 of 1521
TI: Iron and regenerated production: Evidence for biological iron recycling in two marine environments
AU: Hutchins,-D.A.; DiTullio,-G.R.; Bruland,-K.W.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 6, pp. 1242-1255
LA: English
ER: M (Marine)
AB: The authors investigated biological Fe recycling in plankton communities from two contrasting marine ecosystems, the equatorial Pacific and Monterey Bay, California. Our experiments involved addition of cultured cyanobacteria and diatoms labeled with Fe radiotracer to natural plankton communities. Transfer of label into the natural community was followed by size fractionation and microautoradiography, and intracellular Fe was determined with titanium wash techniques. We documented the transfer of labeled Fe from added cyanobacteria to indigenous large cells in both environments and from large diatoms to indigenous small cells in the equatorial Pacific. Microautoradiography and Ti washing verified that transfer occurred from and into intracellular fractions in Monterey Bay experiments, although substantial amounts of transferred Fe were also found to be surface-adsorbed or associated with detritus. We argue that, as is the case for N, recycling of cellular Fe to support regenerated production could be an important component of marine ecosystem dynamics, especially in areas low in Fe.
AN: 3035020
718 of 1521
TI: Bacterial growth efficiency on natural dissolved organic matter
AU: Kroer,-N.
AF: Natl. Environ. Res. Inst., Dep. Mar. Ecol. and Microbiol., Frederiksborgvej 399, DK-4000 Roskilde, Denmark
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 6, pp. 1282-1290
LA: English
ER: M (Marine)
AB: Bacterial growth efficiency was examined in batch cultures and continuous flow cultures by inoculating natural assemblages of pelagic bacteria from different localities into particle-free water. Growth efficiencies were determined from direct measurements of particulate organic carbon (POC) produced and dissolved organic carbon (DOC) used. On average, 6% of the DOC was consumed during growth in batch cultures. Depending on sampling locality, the DOC consumed was converted to bacterial biomass with efficiencies ranging from 26 to 61%. The efficiency did not correlate with either concentration of DOC or temperature. In continuous flow cultures, growth efficiency increased progressively with increasing ammonium concentration but decreased with increasing substrate C:N ratio. The results suggest that the C:N ratio of the bacterial substrate can be a major determinant of bacterial growth efficiency and that differences in growth efficiency between sampling stations can be attributed to differences in the concentration of usable N in the substrate.
AN: 3034965
719 of 1521
TI: Reply to the comment by Jackson (zooplankton and particle flux below the euphotic zone)
AU: Najjar,-R.G.; Toggweiler,-J.R.
AF: Natl. Cent. Atmos. Res., P.O. Box 3000, Boulder, CO 80307, USA
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 6, pp. 1331-1332
LA: English
ER: M (Marine)
AB: In his comment concerning zooplankton and their relationship to the particle flux below the euphotic zone, Jackson (1993) suggests that the assumption of a constant remineralization length scale is important with regard to the conclusions of these modeling studies. In particular, he suggests that a shorter remineralization length scale in regions of higher productivity (where animal populations are greater) would improve simulation of the nutrient distribution. We disagree.
AN: 3034866
720 of 1521
TI: Carbon cycling: Regional and Global Factors Affecting Climate Change
AU: Harger,-J.R.E.; Sorensen,-K.W.; Khalil,-M.A.K.-(eds.)
CO: Conf. on Carbon Cycling: Regional and Global Factors Affecting Climate Change, Kuala Lumpur (Malaysia), 24-26 Oct 1991
SO: CHEMOSPHERE 1993 vol. 27, no. 6, 222 pp
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Because of the current trends in atmospheric carbon dioxide and trace gases and the prospect of global warming, the United Nations Educational, Scientific, and Cultural Organization (UNESCO), the Department of Environment of Malaysia, and the United Nations Environment Program (UNEP) organized this Workshop. The aim of the workshop was to evaluate available data on past, present, and future atmospheric chemical composition (with emphasis on carbon dioxide), the response of marine and terrestrial ecosystems on the enrichment of atmospheric carbon, and to recommend actions to counteract anticipated global climatic warming. In the discussions on present carbon storage and its relation to the Earth's climate, the participants identified the sources of energy and exploitation of forest resources as the two most significant issues related to global climate change. The discussions concluded that anthropogenic contribution of carbon to the atmosphere, through fossil fuel burning, deforestation, and other processes, would be the main mechanism driving climate change. In the future, the necessary increases in the energy needs to support the growth of population and per capita demands of the region and the rest of the world, will dominate the carbon flux to the atmosphere. The study of the past records in relation to climate change is important to test the validity of the hypotheses and assumptions used for climate modeling in predicting future climate change. Moreover, the participants concluded that although we know little about the actual sinks, we know enough to realize that it is prudent to take steps to stabilize the climate since the capacity of natural environment for sequestering carbon has been exceeded by current anthropogenic releases.
AN: 3034542
721 of 1521
TI: (Phenotypic and genetic evolution of enterobacterial pathogens in the marine environment (sediments, biomass).)
OT: Evolution phenotypique et genetique des enterobacteries pathogenes dans le milieu marin (sediments, biomasse)
AU: Gauthier,-M.J.
AF: INSERM, Unit. 303 "Mer et Sante", France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.#CYCLES-BIGEOCHIMIQUES-DE-POLLUTANTS-SPECIFIQUES-ACTIVITA-K.-SURVIE-DES-PATHOGENES. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1991 no. 49 pp. 43-63
ST: MAP-TECH.-REP.-SER. no. 49
LA: French
ER: M (Marine)
AN: 3033397
722 of 1521
TI: (Adaptation of enterobacterial pathogens to sea water (Escherichia coli model).)
OT: Adaptation des enterobacteries pathogenes a l'eau de mer (modele Escherichia coli)
AU: Gauthier,-M.J.; Munro,-P.M.; Breittmayer,-V.A.
AF: INSERM, Unit. 303 "Mer et Sante", France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.#CYCLES-BIGEOCHIMIQUES-DE-POLLUTANTS-SPECIFIQUES-ACTIVITA-K.-SURVIE-DES-PATHOGENES. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1991 no. 49 pp. 33-42
ST: MAP-TECH.-REP.-SER. no. 49
LA: French
ER: M (Marine)
AN: 3033396
723 of 1521
TI: Some environmental factors affecting survival of faecal pathogens and indicator organisms in seawater
AU: El-Sharkawi,-F.; El-Attar,-L.; Abdel-Gawad,-A.; Molazem,-S.
AF: Dep. Environ. Health and Microbiol., High Inst. Public Health, Univ. Alexandria, Egypt
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.#CYCLES-BIGEOCHIMIQUES-DE-POLLUTANTS-SPECIFIQUES-ACTIVITA-K.-SURVIE-DES-PATHOGENES. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1991 no. 49 pp. 21-32
ST: MAP-TECH.-REP.-SER. no. 49
LA: English
ER: M (Marine)
AB: This study is conducted to determine the effect of some environmental factors such as temperature, salinity and light on the rate of die-off Salmonella typhi, S. wein, Shigella flexneri and Escherichia coli as examples of faecal pathogens and indicators in water. These organisms are tested in different kinds of water: seawater, filter sterilized seawater, tap water and normal saline. The organisms were counted every 2 hours for 8 hours and then every day up to 7 days. It is found that there is no great difference in survival time of the organisms tested at temperatures of 25 to 35 degree C, but at 40 degree C they died off more rapidly. The salinity of seawater does not affect the survival time of Salmonella, Sh. flexneri. E. coli appears to survive longer in fresh water than in seawater at temperatures between 30 and 35 degree C. Daylight, i.e. sunlight, has a lethal effect on all test organisms. Survival time being shorter when exposed to daylight than in the dark in different types of waters, being up to a maximum of 24 hours as compared to several days in the dark. Artificial light has less effect than natural daylight.
AN: 3033395
724 of 1521
TI: Survival of some intestinal pathogens in the marine environment
AU: Fuks,-D.
AF: Rudjer Boskovic Inst., Cent. Mar. Res. Rovinj, G. Paliaga 5, 52210 Rovinj, Yugoslavia
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.#CYCLES-BIGEOCHIMIQUES-DE-POLLUTANTS-SPECIFIQUES-ACTIVITA-K.-SURVIE-DES-PATHOGENES. UNEP-Mediterranean-Action-Plan,-Athens-Greece ATHENS-GREECE UNEP 1991 no. 49 pp. 1-20
ST: MAP-TECH.-REP.-SER. no. 49
LA: English
ER: M (Marine)
AB: The purpose of this study is to determine the effects of organic matter, temperature and light intensity on the survival of some Salmonella and Shigella strains, Escherichia coli and faecal coliforms in a marine environment, and in laboratory-performed experiments with natural seawater. The survival of all Salmonella and Shigella strains tested and of faecal coliforms, is higher in all experiments compared to E. coli. The results confirm that sea temperature may exert an important influence on the magnitude of decay rates of salmonellas, shigellas and E. coli. In situ experiments reveal that a large amount of organic matter may overcome the bactericidal effects of sea temperature and light on the bacteria tested. Although the die-off rate of E. coli does not differ significantly from S. typhimurium in some experiments, their different tolerance to light and temperature has to be taken into account particularly when E. coli is utilized as an indicator of S. typhimurium presence in seawater. The discrepancy between die-off rates of S. typhimurium and faecal coliforms increases from 27 m depth to the surface. Even if S. typhimurium and faecal coliforms have similar die-off rates, various combinations of detrimental factors could exert different influence on the tested pathogenic bacteria and indicator bacteria. Therefore, although faecal coliforms should be used as indicators of pathogenic bacteria present in the sea, they should not constitute the only such indicator.
AN: 3033394
725 of 1521
TI: Biogeochemical cycles of specific pollutants (Activity K). Survival of pathogens.
OT: Cycles Biogeochimiques de polluants specifiques (Activite K). Survie des pathogenes
CA: UNEP Mediterranean Action Plan, Athens (Greece)
SO: MAP-TECH.-REP.-SER. ATHENS-GREECE UNEP 1991 no. 49, 72 pp
LA: English
ER: M (Marine)
AB: Contributions are abstracted and indexed individually.
AN: 3033393
726 of 1521
TI: Marine bacterial expression of the RecA gene in response to UV light
AU: Coffin,-R.B.; Jeffrey,-W.H.; Ferrante,-A.A.; Miller,-R.V.
AF: U.S. EPA, Gulf Breeze Environ. Lab., Gulf Breeze, FL 32561, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993 vp
NT: Summary only.
LA: English
ER: M (Marine)
AB: In response to the recent concern for stratospheric ozone depletion the authors examined the effect of natural ultraviolet (UV) radiation on the activity of marine bacteria. Reduction of ozone concentration selectively limits stratospheric adsorption of UV-B (290-320 nm) radiation, resulting in higher radiance on the earth's surface. Oligotrophic marine environments have been a focus of this research because high water clarity allows significant penetration of ultraviolet light to depths of 20 to 30 meters. Increased intensity of UV radiation may have significant effect on the abundance, diversity and evolution of marine bacteria through damage to DNA. A seemingly ubiquitous response in bacteria to DNA damage from UV is the induction of the S.O.S. network by the recA gene product. To study the bacterial response to UV, the authors examined both transcription and translation of the recA gene. Translation was examined using antisera raised against the Escherichia coli RecA protein. Preliminary data suggest that bacteria that are exposed to sunlight in the surface ocean contain higher concentrations of the RecA protein than cells collected from the deep ocean (> 500M). Furthermore, a diel variation in the RecA protein concentration of surface bacteria was observed. Using oligonucleotide gene probes, based on highly concerned regions of the RecA protein. mRNA (transcription) has been measured. The authors are refining this probe and plan to report on comparisons of mRNA and protein concentrations.
AN: 3028444
727 of 1521
TI: Defining the chemical character of aerosols from the atmosphere of the Mediterranean Sea and surrounding regions
AU: Chester,-R.; Nimmo,-M.; Alarcon,-M.; Saydam,-C.; Murphy,-K.J.T.; Sanders,-G.S.; Corcoran,-P.
AF: Oceanogr. Lab., Dep. Earth Sci., Univ. Liverpool, L69 3BX, UK
SO: OCEANOL.-ACTA 1993 vol. 16, no. 3, pp. 231-246
LA: English
ER: M (Marine)
AB: Atmospherically-transported trace metals can play an important role in biogeochemical cycles in the Mediterranean Sea. However, although the magnitude of trace metal air to sea fluxes is initially dependent on the metal concentrations in the air, it is the "chemical character" of the aerosol which constrains the fate of the metals in sea water. To a first approximation the chemical composition of the Mediterranean particulate aerosol is controlled by the extent to which an anthropogenic-rich "background" material, having a mainly European origin, is perturbed by mixing with crustal components having a desert origin. These perturbations offer an environmentally meaningful index which can be used to define the "chemical character" of the Mediterranean particulate aerosol in terms of the manner in which trace metals are partitioned between the anthropogenic and crustal components. This "chemical character" concept was assessed using: a) a total of 83 particulate aerosols collected on a W arrow right E transect across the Mediterranean Sea and surrounding regions; and b) particulate aerosol populations from a number of adjacent coastal seas.
AN: 3027215
728 of 1521
TI: A multilevel model for the study of the dynamics of the North Adriatic Sea
AU: Betello,-G.; Bergamasco,-A.
AF: IBM Eur. Cent. Sci. Eng. Comput., Roma, Italy
CO: Ecological Problems of the Adriatic Sea Symp., Split (Croatia), 7-9 Nov 1990
SO: ECOLOGICAL-PROBLEMS-IN-THE-ADRIATIC-SEA.-A-SYMPOSIUM-HELD-IN-SPLIT,-CROATIA,-7-9-NOVEMBER,-1990. 1991 vol. 32, no. 2 pp. 587-598
ST: ACTA-ADRIAT. vol. 32, no. 2
RN: 3
LA: English
ER: M (Marine)
AB: A method which can be applied to describe, understand and forecast phenomena characterizing a semi-enclosed basin will be discussed. A numerical multilevel model that can be used as a basic structure in biological, geological and chemical research will be presented. In particular its application has been made in the North Adriatic Sea because this area offers the opportunity to study a variety of interesting phenomena. Different numerical experiments were carried out, using 7 km regular grid, 10 vertical levels with different thickness, different boundary conditions, different wind fields; the Po runoff and subsequent advection diffusion of a passive scalar was taken into account. The results of the IBM-3090/VF implementation of the model will be shown.
AN: 3024964
729 of 1521
TI: Primary ocean production: Carbon and particle flux.
OT: Production primaire oceanique: Flux de carbone et de particules
AU: Morel,-A.
CA: Paris-6 Univ. (France)
SO: 1990 8 pp
NT: NTIS Order No.: N91-23596/0/GAR.
LA: French
ER: M (Marine)
AB: The role of the ocean and its vegetation with regard to the carbon and other cycles is discussed. Comprehension of the flux between the atmosphere and the ocean in stationary conditions at the interface and at the interior of the ocean is considered. Present incertitudes with regard to the marine biomass carbon content, the flux entering, the net carbon flux at the base of the superficial layer, and the flux in a column of water down to the sediment are presented. Possible progressions are given. (In Esa, Space and Sea p 233-240.)
AN: 3023004
730 of 1521
TI: Coupling of cycles and global significance of sediment diagenesis
AU: Blackburn,-T.H.; Blackburn,-N.D.
AF: Dep. Microbial Ecol., Inst. Biol. Sci., Aarhus Univ., DK 8000 Aarhus C, Denmark
CO: 7. Meet. of the European Union of Geosciences, Strasbourg (France), 4-8 Apr 1993
SO: MARINE-SEDIMENTS,-BURIAL,-PORE-WATER-CHEMISTRY,-MICROBIOLOGY-AND-DIAGENESIS. 1993 vol. 113, no. 1-2 pp. 101-110
ST: MAR.-GEOL. vol. 113, no. 1-2
LA: English
ER: M (Marine)
AB: A system dynamics simulation model was used to illustrate the interconnections between carbon, nitrogen, sulfur and oxygen cycling in a marine sediment, where sulfide diffusion occurred (Diff+) and where it was absent (Diff-), due to the formation of insoluble compounds. The model contained 12 sediment layers (0.5 mm at the top) and one water layer of 20 m, which was a source for oxygen and sulfate, and a sink for molecules diffusing from the sediments. Particulate organic matter was evenly distributed throughout the sediment down to 3.5 cm. It was allowed to produce dissolved organic carbon (DOC) at low, medium and high rates of 18.6, 37.2 and 55.8 mmol m super(-2)/d, respectively. Because of the distribution of organic matter, the flux of DOC from the sediment was low, 2-3%. Sulfate was the main oxidant of DOC, 81-89% for Diff- and 94-96% for Diff+; O sub(2) and NO sub(3) super(-) were of minor importance as oxidants. Most nitrogen left the sediment as NH sub(4) super(+) (72-95%) with Diff+, but NH sub(4) super(+) efflux was less important in Diff- simulations (16-58%). The difference was due to high rates of nitrification in the latter situation; NO sub(3) super(-) efflux accounted for 38-22% and N sub(2) efflux for 44-18% of the total nitrogen efflux. The high nitrification rates with Diff- were consistent with a large proportion of O sub(2) being used to oxidise NH sub(4) super(+) (72-66% total O sub(2)). Most O sub(2) (91-99%) was used to oxidise HS super(-), where HS super(-) was allowed to diffuse. These data agree with the following explanation: if organic matter is oxidised by SO sub(2) super(2-) reduction, deep in the sediment, and if there is no HS super(-) diffusion, then only NH sub(4) super(+) diffuses to the sediment surface and is oxidised. This is because there is little organic carbon, and no HS super(-), at the sediment surface to compete with NH sub(4) super(+) for O sub(2). The NO sub(3) super(-) which is produced, can then be denitrified efficiently at low organic loading, but at high loading, the sediment becomes more anoxic and the zone of nitrification moves closer to the sediment surface, creating the possibility for a greater NO sub(3) super(-) efflux. The implications of these predictions for global processes are discussed.
AN: 3021949
731 of 1521
TI: Geochemistry of Recent oxic and anoxic marine sediments: Implications for the geological record
AU: Calvert,-S.E.; Pedersen,-T.F.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, BC V6T 1Z4, Canada
CO: 7. Meet. of the European Union of Geosciences, Strasbourg (France), 4-8 Apr 1993
SO: MARINE-SEDIMENTS,-BURIAL,-PORE-WATER-CHEMISTRY,-MICROBIOLOGY-AND-DIAGENESIS. 1993 vol. 113, no. 1-2 pp. 67-88
ST: MAR.-GEOL. vol. 113, no. 1-2
LA: English
ER: M (Marine)
AB: The distributions of certain minor and trace elements in marine sediments should potentially provide forensic tools for determining the redox conditions of the bottom waters at the time of deposition. The ability to identify such conditions in the geological past is important because current models of the conditions of formation of organic-rich rocks require reexamination, a method to determine whether the areal extent of anoxic waters expanded or retracted in response to palaeoceanographic changes is required, and the effects of such environmental changes on the geochemical balance of these elements in the ocean need to be understood. Recent research has suggested that some minor and trace elements are precipitated where free dissolved sulphide is present (Cu, Cd, Ni, Zn) without undergoing a valency change, whereas others undergo a change in valency and are either more efficiently adsorbed onto solid surfaces under oxic (I) or anoxic (V) conditions or are precipitated under anoxic conditions (Cr, Mn, Mo, Re, U, V). Hence, the enrichment of these minor and trace elements relative to their crustal abundances indicates that the host sediments accumulated under anoxic conditions, although not necessarily under anoxic bottom waters. Examination of the chemical composition of the sediments of anoxic basins, continental margin sediments and oxidized deepsea sediments shows that I and Mn enrichments are reliable indicators of bottom water oxygenation, whereas enrichments of the remaining elements reflect either bottom water anoxia or element uptake by subsurface anoxic sediments below a relatively thin surficial oxic veneer. Hence, the absence of metal enrichment in these cases can be taken as firm evidence that the bottom waters of a basin of sedimentation were not anoxic. These behaviours may be used to propose, for example, that the Holocene sapropel in the Black Sea accumulated under oxic bottom waters, whereas the modern facies reflects its formation under the prevailing intensely anoxic conditions, and that the Panama Basin bottom waters were not anoxic during the Last Glacial Maximum when the rate of accumulation of organic carbon increased. Likewise, the enrichment of Mn as a mixed carbonate phase in some ancient black shales strongly suggests that they formed under oxic bottom waters rather than anoxic conditions as is commonly assumed.
AN: 3021926
732 of 1521
TI: Enzymatic iron and uranium reduction by sulfate-reducing bacteria
AU: Lovley,-D.R.; Roden,-E.E.; Phillips,-E.J.P.; Woodward,-J.C.
AF: 430 Natl. Cent., Water Resour. Div., U.S. Geol. Surv., Reston, VA 22092, USA
CO: 7. Meet. of the European Union of Geosciences, Strasbourg (France), 4-8 Apr 1993
SO: MARINE-SEDIMENTS,-BURIAL,-PORE-WATER-CHEMISTRY,-MICROBIOLOGY-AND-DIAGENESIS. 1993 vol. 113, no. 1-2 pp. 41-53
ST: MAR.-GEOL. vol. 113, no. 1-2
LA: English
ER: M (Marine)
AB: The potential for sulfate-reducing bacteria (SRB) to enzymatically reduce Fe(III) and U(VI) was investigated. Five species of Desulfovibrio as well as Desulfobacterium autotrophicum and Desulfobulbus propionicus reduced Fe(III) chelated with nitrilotriacetic acid as well as insoluble Fe(III) oxide, Fe(III) oxide reduction resulted in the accumulation of magnetite and siderite. Desulfobacter postgatei reduced the chelated Fe(III) but not Fe(III) oxide. Desulfobacter curvatus, Desulfomonile tiedjei, and Desulfotomaculum acetoxidans did not reduce Fe(III). Only Desulfovibrio species reduced U(VI). U(VI) reduction resulted in the precipitation of uraninite. None of the SRB that reduced Fe(III) or U(VI) appeared to conserved enough energy to support growth from this reaction. However, Desulfovibrio desulfuricans metabolized H sub(2) down to lower concentrations with Fe(III) or U(VI) as the electron acceptor than with sulfate, suggesting that these metals may be preferred electron acceptors at the low H sub(2) concentrations present in most marine sediments. Molybdate did not inhibit Fe(III) reduction by D. desulfuricans. This indicates that the inability of molybdate to inhibit Fe(III) reduction in marine sediments does not rule out the possibility that SRB are important catalysts for Fe(III) reduction. The results demonstrate that although SRB were previously considered to reduce Fe(III) and U(VI) indirectly through the production of sulfide, they may also directly reduce Fe(III) and U(VI) through enzymatic mechanisms. These findings, as well as our recent discovery that the S degree -reducing microorganism Desulfuromonas acetoxidans can reduce Fe(III), demonstrate that there are close links between the microbial sulfur, iron, and uranium cycles in anaerobic marine sediments.
AN: 3021904
733 of 1521
TI: Marine sediments, burial, pore water chemistry, microbiology and diagenesis
CO: 7. Meet. of the European Union of Geosciences, Strasbourg (France), 4-8 Apr 1993
SO: MAR.-GEOL. 1993 vol. 113, no. 1-2, 145 pp
LA: English
ER: M (Marine)
AB: This volume includes papers on sediment chemistry, specific indicators of biogeochemical processes in the geological past and how they responded to environmental change, and the role of microbes in biogeochemical cycles.
AN: 3021749
734 of 1521
TI: Microbial formation and transformation of organometallic and organometalloid compounds
AU: Gadd,-G.M.
AF: Dep. Biol. Sci., Univ. Dundee, Dundee DD1 4HN, UK
SO: FEMS-MICROBIOL.-REV. 1993 vol. 11, no. 4, pp. 297-316
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Microbial formation and transformation of organometallic and organometalloid compounds comprise significant components of biogeochemical cycles for the metals mercury, lead and tin and the metalloids arsenic, selenium, tellurium and germanium. Methylated derivatives of such elements can arise as a result of chemical and biological mechanisms and this frequently results in altered volatility, solubility, toxicity and mobility. The major microbial methylating agents are methylcobalamin (CH sub(3)CoB sub(12)), involved in the methylation of mercury, tin and lead, and S-adenosylmethionine (SAM), involved in the methylation of arsenic and selenium. Evidence for the methylation of other toxic metal(loid)s is sparse. Biomethylation may result in metal(loid) detoxification since methylated derivatives may be excreted readily from cells, are often volatile and may be less toxic, e.g. organoarsenicals. However, for mercury, low yields of methylated derivatives and the existence of more efficient resistance mechanisms, e.g. reduction of Hg super(2+) to Hg super(0), suggest a lower significance in detoxification. Bioalkylation has only been characterised in detail for arsenic. Microorganisms can accumulate organometal(loid)s, a phenomenon relevant to toxicant transfer to higher organisms. As well as bioaccumulation, many microorganisms are capable of the degradation and detoxification of organometal(loid) compounds by, e.g. demethylation and dealkylation. Several organometal(loid) transformations have potential for environmental bioremediation.
AN: 3020847
735 of 1521
TI: The Parana floodplain lakes (Argentina): Overview of major hydrological, biogeochemical, and ecological features
AU: Carignan,-R.; Neiff,-J.J.
AF: INRS, Univ. Quebec, C.P. 7500, Ste-Foy, PQ G1V 4C7, Canada
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993 vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Compared to other major South American rivers, relatively low flood amplitude and unpredictable hydrology confer distinct biogeochemical and ecological attributes to the floodplain lakes of the Parana River. Direct influx of dissolved nutrients from the river is uncommon and nutrient cycles are usually dominated by internal sources. Floating macrophyte production is limited by N during summer, whereas phytoplankton production can be limited by N or by light in the more turbid systems. Remote sensing (SPOT) and field observations suggest that morphometry and turbidity determine to a large extent whether the lakes will be dominated by floating macrophytes (Eichhornia), submerged macrophytes (Cabomba), or phytoplankton. Because successive flood events vary in amplitude, duration and timing, their effects on the lakes are highly variable from year to year.
AN: 3020259
736 of 1521
TI: The silica cycle in the Antarctic Ocean: Is the Weddell Sea atypical?
AU: Leynaert,-A.; Nelson,-D.M.; Queguiner,-B.; Treguer,-P.
AF: Inst. d'Etudes Mar., URA CNRS 1513, BP 452, F-29275 Brest Cedex, France
SO: MAR.-ECOL.-PROG.-SER. 1993 vol. 96, no. 1, pp. 1-15
NT: Bibliogr.:61 ref.
LA: English
ER: M (Marine)
AB: The lowest biogenic silica production rates in the Southern Ocean (average of 2.59 mmol Si m super(-2)/d) have been recorded in an area of heavy ice cover along a transect through the Weddell Sea from Joinville Island to Cap Norvegia (November-December 1990). The associated biomass was also very low (concentrations less than or equal to 0.6 mu mol/l for biogenic silica and less than or equal to 0.8 mu g/l for chlorophyll a). Based upon these direct measurements of biogenic silica production rates and other data available from the marginal ice zone and open ocean areas, we estimated the annual production of biogenic silica in the northern Weddell Sea to be 810 to 870 mmol m super(-2)/yr. This leads to a revised estimate of the total annual biogenic silica production in the Southern Ocean of between 11 and 32 Tmol Si/yr. Comparing our annual production estimate to previous estimates of vertical flux of opal in the Weddell Sea, we conclude that no more than 1% of the silica produced annually by phytoplankton in the upper water column reaches a depth of 800 m. This is consistent with the general distribution of high accumulation rates of opal in Southern Ocean sediments which evidence an unexplained gap in the Weddell Sea. Thus, regarding the cycling of biogenic silica in the Southern Ocean, the Weddell Sea appears to be atypical.
AN: 3020085
737 of 1521
TI: A coupled physical-biochemical lake model for forecasting water quality. Application to the Northern Basin of Lake Lugano
AU: Karagounis,-I.; Troesch,-J.; Zamboni,-F.
AF: Lab. Hydraul., Hydrol. and Glaciol., ETH-Zentrum, CH-8092 Zurich, Switzerland
SO: AQUAT.-SCI. 1993 vol. 55, no. 2, pp. 87-102
LA: English
ER: F (Freshwater)
AB: A new one-dimensional numerical model that includes physical and biochemical processes has been developed. The biochemical processes, influenced by the lake dynamics, are required for forecasting water quality. The model is used to investigate the effects of different internal restoration measures, such as artificial mixing, input of oxygen and drainage of deep water. The model is applied to the Northern Basin of Lake Lugano, a Swiss-Italian border lake. The lake is highly eutrophic and chemically stratified throughout the year. The model was calibrated over one year and validated over a period of several years. The results agree well with the measured data. The coupled model reproduces the observed depth dependency of conductivity even during long simulation times. Due to the predominant mixing, decoupled physical models cannot maintain such gradients. The forecasting capabilities of the model are demonstrated for different case studies. The impact of restoration measures on water quality is rather small. Best results are achieved by reducing the external nutrient loading. Caution is recommended for internal measures as these have to be studied in greater detail.
AN: 3018928
738 of 1521
TI: Enhanced particle flux through the biodeposition by the Antarctic suspension-feeding bivalve Laternula elliptica in Marian Cove, King George Island
AU: Ahn,-In-Young
AF: Polar Ecol. Lab., Polar Res. Cent., Korea Ocean Res. and Dev. Inst., Ansan, P.O. Box 29, Seoul 425-600, South Korea
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1993 vol. 171, no. 1, pp. 75-90
LA: English
ER: M (Marine)
AB: The infaunal lamellibranch Laternula elliptica (Laternulidae), one of the most Antarctic bivalves, is widely distributed in shallow waters around the Antarctic Continent. In order to evaluate the contribution of this species to organic carbon flux in an Antarctic coastal ecosystem, biodeposition rates by L. elliptica were measured and compared with sedimentation without this bivalve species in laboratory experiments during one austral summer. The amount of deposited material increased in the presence of L. elliptica. Weight-specific biodeposition rates varied from 0.26 to 2.17 mg dry wt/g wet wt/d and the rate decreased with increase in body weight. Due to massive inflows of terrigenous sediment through coastal meltwater stream into the coastal water, fecal and pseudofecal material contained a considerable amount of mineral particles and only a small percentage of organic carbon (1.6-5.2%). Estimated particulate organic carbon flux through the biodeposition of L. elliptica is [95 mg C/m super(2)/d, an amount comparable to that of a typical suspension-feeding bivalve, Mytilus edulis, L. elliptica is apparently an important agent for sedimentation of both lithogenic particles and organic particles. Thus, this study suggests that L. elliptica play an important role in enhancing particle flux from water column to sea bed through biodeposition and possibly nourishing other benthic fauna, particularly in phytoplankton-impoverished nearshore waters.
AN: 3018639
739 of 1521
TI: Nuclear and isotopic techniques for investigating marine pollution
AU: Mee,-L.D.; Readman,-J.W.
AF: IAEA-MEL's Mar. Environ. Stud. Lab.
SO: IAEA-BULL. 1993 vol. 35, no. 2, pp. 2-8
LA: English
ER: M (Marine)
AB: A survey of selected applications that scientists are using to identify, trace, and investigate contamination of the oceans.
AN: 3014576
740 of 1521
TI: Community structure and functional roles of meiofauna in the North Sea
AU: Heip,-C.; Huys,-R.; Alkemade,-R.
AF: Cent. Estuar. Coastal Ecol., Netherlands Inst. Ecol., Vierstr. 28, 4401 EA Yerseke, Netherlands
CO: The Other North Sea, Amsterdam (Netherlands), 21 Feb 1992
SO: THE-OTHER-NORTH-SEA:-PROCEEDINGS-OF-A-SYMPOSIUM. 1992 vol. 26, no. 1 pp. 31-41
ST: NETH.-J.-AQUAT.-ECOL. vol. 26, no. 1
LA: English
ER: M (Marine)
AB: Knowledge on community structure of North Sea meiofauna has greatly increased recently. A quasi-synoptic picture of meiofauna densities and copepod community structure from 171 stations of the southern North Sea, sampled in April-May 1986, has been obtained during the North Sea Benthos Survey. Latitudinal patterns in meiofauna abundance and copepod weight, abundance and diversity exist in an area between 51 degree 30'N and 58 degree 30'N. Using TWINSPAN-classification five major groups of copepod species can be recognized which are related to sediment type, latitude and depth. The part of the meiofauna in total benthic energy flow, their role in the benthic food web and in biogeochemical cycles is discussed based on existing literature. There are still considerable gaps in knowledge and the field is not progressing rapidly.
AN: 3013582
741 of 1521
TI: Dynamics of dimethylsulfide in coastal waters and the marine atmosphere: A need for platform observations
AU: Dacey,-J.W.H.; Cooper,-D.J.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA, USA
SO: MAR.-TECHNOL.-SOC.-J. 1993 vol. 27, no. 2, pp. 72-77
NT: Offshore Platform Technology for Science.
LA: English
ER: M (Marine)
AB: Time series measurements of dimethylsulfide in seawater and in the atmosphere will yield valuable insight into the variability of and the controls on this rapidly cycling and important biogeochemical compound. It is vitally important to have access to a stable platform that will allow measurements during periods of high wind speed when gas exchange is rapid and when shipboard measurements are impossible. Assessment of ancillary parameters in the water will increase our understanding of the biological and physical factors influencing DMS cycling in seawater. Simultaneous measurements in the surface water in the atmospheric boundary layer will allow evaluation of sea-air flux models and will aid in unravelling the proposed climate feedbacks associated with DMS.
AN: 3013247
742 of 1521
TI: Technology and related developments for interdisciplinary global studies
AU: Dickey,-T.D.
AF: Univ. Southern California, Univ. Park, Los Angeles, CA 90089, USA
SO: SEA-TECHNOL. 1993 vol. 34, no. 8, pp. 47-54
LA: English
ER: M (Marine)
AB: The term global change usually connotes climate change--a bias toward physical aspects. However, it involves considerably more diverse and complex set of scientific problems related to the biology and chemistry of our planet. For this reason, interdisciplinary research directed toward global scale problems has become the focus for many oceanographers recently. Major programs such as the Joint Global Ocean Flux Study (JGOFS) and the Global Ocean Ecosystem Dynamics (GLOBEC) programs are well underway. The U.S. components are primarily administered and funded by NSF with additional funds from agencies such as NOAA, NASA, ONR, DOE, and EPA. Both programs have international components and coordinating organizations critical to their success.
AN: 3013049
743 of 1521
TI: Lake-groundwater interaction: Critical needs, new approaches
AU: Bowser,-C.J.
AF: Dep. Geol. and Geophys., Univ. Wisconsin, Madison WI, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993 vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Lakes are not isolated from their terrestrial surroundings, and a better understanding of interactions of lakes with surrounding terrestrial regions is critically needed. Because of their higher solute concentrations groundwaters exert considerable chemical "leverage" on lakes. Groundwater flow modeling has been relatively expensive from the standpoint of personnel training, drilling costs, and computer modeling requirements. Recently other methods have been used to estimate lake hydrologic budgets that are potentially much less costly. Use of stable isotopic tracers of oxygen and deuterium enable evaluation of lake hydrologic budgets, and, through inverse techniques, enable determination average input groundwater composition. Results from a LTER site in northern Wisconsin provide new insights into silica cycling in lakes, potassium loading from leaf litterfall, and road salt contamination. Mass balance approaches combined with more careful analysis of mineralogical and geological characteristics of surrounding terrain can help better define the controls on the composition of these waters. Other isotopic systems (e.g. super(87)Sr/ super(86)Sr, delta super(13)C) can further improve these models.
AN: 3011951
744 of 1521
TI: Meromixis in hypersaline Mono Lake, California. 3. Biogeochemical response to stratification and overturn
AU: Miller,-L.G.; Jellison,-R.; Oremland,-R.S.; Culbertson,-C.W.
AF: U.S. Geol. Survey, Water Resour. Div., Menlo Park, CA 94025, USA
SO: LIMNOL.-OCEANOGR. 1993 vol. 38, no. 5, pp. 1040-1051
LA: English
ER: B (Brackish)
AB: Mono Lake is a terminal, saline lake that became ectogenically meromictic in 1982-1983 and remained stratified until November 1988. During this period, the monimolimnion remained anoxic and nearly isothermal, while the upper mixolimnion was well oxygenated and exhibited a seasonal thermal regime. Dissolved sulfide and methane increased in the monimolimnion as a result of diffusive flux from the sediments. Winter mixing down to the chemocline distributed sulfide and methane throughout the mixolimnion. Lakewide inventories of dissolved sulfide and methane reflected the balance between increased concentrations and decreased monimolimnion volume over time. At overturn, the entire water column was isothermal and anoxic. Dissolved sulfide (380 x 10 super(6) mol) was oxidized in 1 week by molecular oxygen. Methane (12 x 10 super(6) mol) was removed more slowly by microbial oxidation and ventilation across the air-water interface.
AN: 3005617
745 of 1521
TI: A coccolithophorid bloom in Jervis Bay, Australia.
AU: Blackburn,-S.I.; Cresswell,-G.
AF: Div. Fish., CSIRO, GPO Box 1538, Hobart, Tas. 7001, Australia
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1993. vol. 44, no. 2, pp. 253-260
LA: English
ER: M (Marine)
AB: A massive algal bloom of the coccolithophorid Gephyrocapsa oceanica Kamptner (Prymnesiophyceae) developed in Jervis Bay, a coastal embayment at 34 degree S on the New South Wales coast, in mid December 1992. The bloom coloured the entire bay a dramatic milky blue-green, which was clearly visible from aircraft and detectable in the visible band by the US satellite NOAA-11. The bloom, which reached cell densities of 1.8 x 10 super(7) cells/L, persisted for a month. Such high densities of coccolithophorids have not been recorded before in Australian waters. Furthermore, it is the first record, world-wide, of a large-scale mono-specific bloom of G. oceanica). The bloom is suggested to have been driven by an intrusion of continental-slope water that continuously entered into the bottom of the bay.
AN: 3004423
746 of 1521
TI: Fate of a phytoplankton spring bloom: Sedimentation and carbon flow in the planktonic food web in the northern Baltic.
AU: Lignell,-R.; Heiskanen,-A.-S.; Kuosa,-H.; Gundersen,-K.; Kuuppo-Leinikki,-P.; Pajuniemi,-R.; Uitto,-A.
AF: Dep. Limnol., Univ. Helsinki, SF-00710 Helsinki, Finland
SO: MAR.-ECOL.-PROG.-SER. 1993. vol. 94, no. 3, pp. 239-252
NT: Bibliogr.: 77 ref.
LA: English
ER: B (Brackish)
AB: During the spring bloom in 1988, the dynamics of planktonic carbon flow were studied weekly in the euphotic layer in the northern Baltic. The spring bloom developed after the formation of a slight vertical salinity gradient near the surface at the end of April, and a peak in phytoplankton primary productivity and biomass (dominated by the dinoflagellate Peridiniella catenata ) was reached about 1 wk later. The biomass of all heterotrophic compartments, especially that of bacteria and copepods, increased strongly during the peak and declining phases of the algal bloom, showing that their success was closely linked with the bloom. During the whole bloom period, the integral primary production ( super(14)C incorporation) was 45.5 g C/m super(2), and "new" (NO sub(3)@)u--N-based) production contributed about 80% of this value. The rotifers-copepods grazing chain and the bacteria-heterotrophic nanoflagellates-ciliates "microbial loop" consumed directly about the same amount (3.5 g C/m super(2)) of phytoplankton carbon. Algae accounted for 64% of the total carbon consumption of zooplankton.
AN: 3001866
747 of 1521
TI: Decomposition of mud-flat annual plant litter on a drawdown marsh surface.
AU: Wrubleski,-D.A.; Murkin,-H.R.; Van-Der-Valk,-A.G.; Davis,-C.B.
AF: Inst. Wetland and Waterfowl Res., Iowa State Univ. Ames, IA 50011, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: This study examined the decomposition of above- and below-ground plant litter of three dominant mud-flat annuals (Aster brachyactis , Atriplex patula and Chenopodium rubrum ) during an experimental drawdown of a 10-cell complex in the Delta Marsh, Manitoba. Aboveground shoots exhibited a near linear loss of mass over the two years of the experiment, with little difference between species. Belowground roots of Aster and Atriplex lost mass at a faster rate than shoots during the first year, whereas the opposite was found for Chenopodium . The roots of all three species exhibited little mass loss during the second year. After two years all plant litters had similar mass remaining except for Chenopodium roots which had lost the least amount. All litters released phosphorus over the two years, except Chenopodium roots which nearly doubled in total phosphorus. Nitrogen levels were much more varied between species and parts.
AN: 3001702
748 of 1521
TI: Dissolved inorganic carbon utilization in relation to calcite production in Emiliania huxleyi (Lohmann) Kamptner.
AU: Dong,-L.F.; Nimer,-N.A.; Okus,-E.; Merrett,-M.J.
AF: Sch. Biol. Sci., University Coll. Swansea, Singleton Park, Swansea SA2 8PP, UK
SO: NEW-PHYTOL. 1993. vol. 123, no. 4, pp. 679-684
LA: English
ER: F (Freshwater)
AB: The relationship between calcite production and dissolved inorganic carbon (DIC) utilization was investigated using high- and low-calcifying strains of Emiliania huxleyi aerated with either air (0.03% v/v CO sub(2)) or CO sub(2)-free air. With cultures grown on air, calcite production was eight-fold greater in the high-calcifying culture, but growth rates for high- and low-calcifying cultures were similar. Growth and calcite production were accompanied by a concomitant decrease in DIC and free CO sub(2) in the high-calcifying culture, showing that HCO sub(3) super(-) provides inorganic carbon for calcite synthesis. In low-calcifying cultures DIC and free CO sub(2) were relatively constant, confirming that cells acquire inorganic carbon mainly by the diffusive entry of free CO sub(2). When cultures were aerated with CO sub(2)-free air the free CO sub(2) concentration was below the K sub(0.5)(CO sub(2)) for high- and low-calcifying cells and the low-calcifying cells were unable to grow. Growth of high-calcifying cells was observed, and the calcite yield was little changed from cultures gassed with air (0.03% v/v CO sub(2)). At these minimal CO sub(2) concentrations HCO sub(3) super(-) may provide inorganic carbon for calcite synthesis and CO sub(2) for photosynthesis, allowing growth to occur. Calcite synthesis by E. huxleyi) decreases DIC and carbonate alkalinity in cultures not in equilibrium with the gas phase.
AN: 3001480
749 of 1521
TI: The release of trace elements by dying marine phytoplankton.
AU: Fisher,-N.S.; Wente,-M.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP.. 1993. vol. 40, no. 4, pp. 671-694
LA: English
ER: M (Marine)
AB: The extent to which sinking phytoplankton can directly influence the cycling and vertical transport of metals in the oceans depends largely on the loss rates of the metals from dying cells during their descent. This was examined in a series of radiotracer experiments in which a diatom, a dinoflagellate, and a coccolithophore each accumulated Se, Ag, Sn, Au and Am and then were maintained in the dark for up to 10 days to assess depuration kinetics. Concurrent measurements were made of cell counts and particulate C, N and dry weight. Se was taken up actively by the cells, Sn and Am passively, and Ag and Au uptake patterns varied with the species. The coccolithophores had less reactive surfaces for these metals than did the other species, as reflected in lower metal uptake and greater metal release. Generally, those metals with greatest particle affinity during uptake (Am, Sn, Ag) were retained for the longest periods. All cells decomposed over time, so that particulate C and N decreased by up to 10.7 and 9.8%/day, respectively, in diatom cultures, up to 4.7 and 4.9%/day in dinoflagellate cultures, and up to 6.5 and 6.0%/day in coccolithophore cultures. In the diatoms, all elements except Se were released more slowly than C and N from the particulate phase, resulting in increasing metal:C (or N) ratios with time, while Se was released faster than C or N. With the dinoflagellates, elemental release generally followed C and N release, while with the coccolithophores elements were released more rapidly than C and N from the particulate phase. Metals (especially Am, Ag, Sn) were retained sufficiently long, even by decomposing cells, to suggest that phytoplankton sinking as aggregates at rates of 100 m/day would effectively transport these metals hundreds of meters out of oceanic surface waters.
AN: 2996790
750 of 1521
TI: Changes in the functioning of wetlands along environmental gradients.
AU: Brinson,-M.M.
AF: Dep. Biol., East Carolina Univ., Greenville, NC 27858, USA
SO: WETLANDS. 1993. vol. 13, no. 2, spec. iss., pp. 65-74
LA: English
ER: F (Freshwater)
AB: One of the prevalent gradients in wetlands is the continuum of depth and frequency of flooding. While much emphasis has been placed on the importance of hydrology as a driving force for wetlands, few other perspectives have emerged to demonstrate unifying patterns and principles. In contrast to the wetness continuum, the functioning of wetlands can be separated into two broad categories: (1) landscape-based transitions that occur within a wetland or group of similar wetland types and (2) resource-based transitions that allow comparisons of the flow of water and processing of nutrients among very different wetland types. Landscape-based continua include the transition from upstream to downstream in riverine wetlands and between aquatic and terrestrial ecosystems within a wetland. Along the upstream-downstream continuum, sources of flood-water delivery change dominance from ground-water discharge and overland runoff, as in low order streams, to dominance by overbank flooding, as in high order streams. With increasing size, properties related to the aquatic-to-terrestrial transition are replaced by properties related to wetland-atmospheric exchanges and by landscape maintenance, the latter not normally acknowledged as a wetland function. Resource-based continua include the extremes of (1) sources of water to wetlands (precipitation, overland flow, and ground water) and (2) the variation in inflows and outflows of nutrients and sediments. Emphasis on water source forces consideration of controls beyond the wetland's boundaries. A broader view of biogeochemical functioning is gained by categorizing wetlands into groups based on the exchange of nutrients and sediments among landscape units rather than on serving as a sink or source for a particular element. Based on this analysis, the less frequently flooded or saturated portions of wetlands are no less functionally active than wetter portions; the functions are simply different. Efforts to classify wetlands according to their hydroperiod do little to reveal their fundamental properties.
AN: 2995986
751 of 1521
TI: Role of zooplankton in the cycling and remineralization of chemical materials in the Southern California Bight. Progress report 5, June 15-November 14, 1988.
CA: Oregon State Univ., Corvallis (USA). Sch. of Oceanography
SO: REP.-U.S.-DEP.-ENERGY. 1988. 5 pp
NT: NTIS Order No.: DE90006696/GAR.
LA: English
ER: M (Marine)
AB: The overall objective of our research is to understand the transport pathways and mass balances of selected metabolically active and inactive chemical species in the Santa Monica/San Pedro Basins. One focus of our study is to examine the role of zooplankton and micronekton in the cycling and remineralization of chemical materials in the Southern California Bight, with particular reference to C, N and certain radionuclides and trace metals. A second focus is to examine these same radionuclides and trace metals in other important reservoirs. Knowledge of the rates and routes of transfer of these nuclides and metals through these reservoirs should lead to a cogent model for these elements in SM/SP Basins. Our zooplankton C and N data, should lead ultimately to a model of C and N cycling in the upper water column. Our sediment core data will lead to the construction of mass balances and budgets in the SM/SP Basins. (Contract FG05-85ER60340. Sponsored by Department of Energy, Washington, DC. Portions of this document are illegible in microfiche products.)
AN: 2995275
752 of 1521
TI: Atmospheric oxygen variation through geologic time.
AU: Kump,-L.R.; Kasting,-J.F.; Robinson,-J.M.
AF: Earth System Sci. Cent., Pennsylvania State Univ., University Park, PA 16802, USA
CO: Atmospheric Oxygen Variation Through Geologic Time, University Park, PA (USA), 16-18 Jul 1990
SO: GLOBAL-PLANET.-CHANGE. 1991. vol. 5, no. 1-2, 131 pp
NT: Palaeogeogr., Palaeoclimatol., Palaeoecol. vol. 97, no. 1-2.
LA: English
AB: Molecular oxygen is an important component of the Earth system. Its atmospheric abundance substantially influences the chemical behavior of the atmosphere, the metabolism of organisms, photosynthesis, respiration, and decomposition on land and in the ocean, the frequency and intensity of forest fires, and crustal weathering processes. Although on societal time scales the abundance of O sub(2) is unchanging, on geologic time scales the possibility of substantial fluctuations exists. The timing, magnitude, causes, and effects of O sub(2) variation through Earth history are, however, poorly known. In hope of stimulating such investigation, a workshop attended by experts in the fields of atmospheric chemistry, paleontology, geochemistry, physiology, and ecology was held at the Earth System Science Center of the Pennsylvania State University from July 16-18, 1990. The workshop was divided into three sessions. The first session addressed the functional, quantitative, and diagnostic aspects of O sub(2) in modern biogeochemical cycles. The second and final sessions focussed on theoretical, empirical, and inferential indicators of oxygen variations over Phanerozoic (the last 600 Ma), and Precambrian (from 3.8 Ga to 0.6 Ga) time, respectively.
AN: 2990317
753 of 1521
TI: Composition, productivity and nutrient chemistry of a coastal ocean planktonic food web.
AU: Verity,-P.G.; Yoder,-J.A.; Bishop,-S.S.; Nelson,-J.R.; Craven,-D.B.; Blanton,-J.O.; Robertson,-C.Y.; Tronzo,-C.R.
AF: Skidaway Inst. Oceanogr., P.O. Box 13687, Savannah, GA 31416, USA
SO: CONT.-SHELF-RES. 1993. vol. 13, no. 7, pp. 741-776
LA: English
ER: M (Marine)
AB: A 3 year field study was conducted to investigate patterns, magnitude and variability of primary production; the abundance, biomass and composition of producers and consumers; and the relative importance of physical and chemical variables associated with these parameters, in inner shelf waters of the South Atlantic Bight. Discrete interval, time series and continuous measurements were made along a transect and at two process-oriented stations during summer and winter 1985-88. A quasi-permanent density front constrains low salinity (<34 ppt) waters to within ca 10 km of the coast. These waters contain abundant autotrophic and heterotrophic communities. Primary production is high, 6-7 x 10 super(2) gC/m super(-2)/year, and is apparently subsidized by rapid nutrient recycling in the water column, sediments and adjacent salt marshes. Silicate is notable for its excess concentrations year-round and supports substantial diatom productivity. Correlation analyses suggest that Si strongly influences phytoplankton biomass, whereas growth rates are coupled to availability of light and NH sub(4). Despite evidence of considerable variability in primary production over daily to interannual scales, plankton biomass is relatively constant. Experimental studies suggest a tight coupling between primary producers and microconsumers, and support the hypothesis that substantial fractions of primary and secondary production are recycled within the water column.
AN: 2989778
754 of 1521
TI: Artificial nutrient enrichment of two meromictic lakes in southeast Alaska to rehabilitate indigenous sockeye salmon (Oncorhynchus nerka ) populations.
AU: Barto,-D.L.; Haddix,-M.
AF: Alaska Dep. Fish and Game, F.R.E.D. Div., Limnol. Sect., Juneau, AK 99824, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Previous studies of sockeye salmon (Oncorhynchus nerka ) nursery lakes have indicated that the decomposition of adult salmon carcasses can contribute approximately 66% of the total annual nutrient inputs to Alaskan coastal lakes. Gradually declining adult salmon production from Hugh Smith and Redoubt lakes is generally believed to be the direct result of over-fishing. The subsequent decline in returning adult salmon has also reduced the nutrient inputs and the overall lake productivity which directly effects adult fish production. Investigations since 1979 characterized these lakes as having low average nutrient (total P < 5.0 ug/l), Chl sub(-)a) (<2.0 ug/l) and zooplankton biomass levels and containing monimolimnion layers at depths >80 m. Artificial enrichment delivered liquid ammonium nitrate and ammonium phosphate fertilizer to increase the in-lake total P levels to 5-10 ug/l. Primary and secondary productivity increased during fertilizer application periods while the total P levels did not exceed 90% of the critical loading rates. Zooplankton biomass production doubled at one lake as a direct result of the artificial nutrient additions. Growth and survival indices of juvenile sockeye generally increased and at one lake adult sockeye production increased five fold.
AN: 2989658
755 of 1521
TI: PCBs in Lake Michigan: Linkages to the cycles of biogenic particles and organic carbon.
AU: Armstrong,-D.E.; Shafer,-M.M.; Dean,-K.E.
AF: Univ. Wisconsin, Madison, WI 53706, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
LA: English
ER: F (Freshwater)
AB: Research on the fate and effects of polychlorobiphenyls (PCBs) in Lake Michigan has provided insights into biogeochemical cycles and processes. The fate of PCBs is linked to the cycles of organic carbon and natural particles. Organic carbon, especially lipids, in biogenic particles transports PCBs to bottom sediments. Particle diagenesis in surface sediments removes organic carbon and recycles PCBs into the water column. Organic colloids produced by chemical and biological processes influence removal through particle scavenging, volatilization, and degradation. Ingestion of organic particles incorporates PCBs into the food web. Quantitative information on the pathways of carbon and other biogenic elements in the ecosystem has been obtained from research on PCBs.
AN: 2989477
756 of 1521
TI: The use of carbon isotopes to evaluate sources and sinks of dissolved inorganic carbon in lake watersheds.
AU: Aravena,-R.; Schiff,-S.; Trumbore,-S.; Dillon,-P.
AF: Waterloo Centr. Groundwater Res., Univ. Waterloo, Waterloo, ON N2L 3G1, Canada
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
LA: English
ER: F (Freshwater)
AB: Growing concerns about the global carbon cycle, and the natural and anthropogenic sources and sinks of carbon have fostered renewed research interest in the cycling of carbon in natural systems. This presentation will focus on the use of carbon isotopes ( super(13)C, super(14)C) to evaluate cycling of dissolved inorganic carbon (DIC) in lake watersheds. Chemical and carbon isotope data collected in acid sensitive lake watersheds in northern Ontario will be presented to illustrate processes that control the carbon isotopic composition of DIC and its use to evaluate DIC fluxes between the main carbon pools that are involved in carbon cycling in lake watersheds.
AN: 2989476
757 of 1521
TI: Evidence for the diffusion of dissolved organic carbon from the sediments of Lake Fryxell, Antarctica.
AU: Aiken,-G.R.; McKnight,-D.M.
AF: U.S. Geol. Surv., Mar. St. Sci. Cent., 3215 Mar. St., Boulder, CO 80303, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Dissolved organic carbon (DOC) in Lake Fryxell, an amictic, permanently ice-covered lake, was studied to determine the influence of biogeochemical processes on its distribution and nature. The DOC depth profile is similar to the profiles for conservative inorganic constituents, such as chloride, indicating that diffusion of organic matter from the bottom waters or sediments of the lake into overlying glacial melt water is the major source of DOC. The super(14)C ages of the lake fulvic acids suggest that DOC diffusing from the bottom waters is primarily composed of relict organic material with the addition of recent carbon resulting from the degradation of algae and bacteria in the sediments and bottom waters of the lake. The main transformations occurring as aquatic humic substances diffuse upward in the water column are 1) loss of sulfur groups through the oxycline and 2) decrease in aliphatic carbon and increase in the heterogeneity of aliphatic moieties.
AN: 2989467
758 of 1521
TI: The role of manganese reduction in the biogeochemical cycling of manganese in Oneida Lake, New York.
AU: Aguilar,-C.; Nealson,-K.H.
AF: Cent. Great Lakes Stud., Univ. Wisconsin-Milwaukee, Milwaukee, WI 53204, USA
CO: ASLO and SWS 1993 Annu. Meet., Edmonton, AB (Canada), 30 May-3 Jun 1993
SO: ASLO-AND-SWS-1993-ANNUAL-MEETING.-ABSTRACTS. USA ASLO-SWS 1993. vp
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Manganese is a very reactive redox metal, which exhibits a strong yearly cycle in Oneida Lake, New York. Different methods were used to measure Mn(II) fluxes from the sediments throughout the year. In deep basins of the lake, high rates of Mn(IV) reduction, up to 2.1 mmol/m super(2)/day, were observed during the summer and early fall, with little reduction taking place during the rest of the year. In the shallow areas of the lake, where ferromanganese nodules and crusts are commonly found, there was little or no reduction throughout the year. The manganese cycle is tightly coupled to the carbon cycle, and has a significant role in the oxidation of organic carbon in the lake, derived from the high photosynthetic production and the biomass that collapses and reaches the sediment-water interface.
AN: 2989465
759 of 1521
TI: Systemecological analysis of marine pelagial systems on behalf of microbiological/ planktological variables and pDNA measurements.
OT: Systemoekologische Analyse marine Pelagialsysteme auf der Basis von mikrobiologisch/ planktologischen Variablen und pDNA-Messungen
AU: Karrasch,-B.
AF: Inst. Meereskd., Abt. Mar. Mikrobiol., Duesternbrooker Weg 20, D 24105 Kiel, FRG
CA: Kiel Univ. (FRG). Math.-Nat. Fak.
SO: BER.-INST.-MEERESKD.-CHRISTIAN-ALBRECHTS-UNIV.-KIEL. 1992. vol. 225, 197 pp
NT: Bibliogr.: 327 ref. Diss. (Dr. rer. nat.)
LA: German
ER: M (Marine); B (Brackish)
AB: During spring and summer 1989 investigations were made in 2 areas of the North Atlantic (47 degree N, 20 degree W; 57 degree N, 20 degree W). Further investigations were carried out from late spring to summer in Kiel Bight and Kiel Fjord and in the Western Baltic and during summer 1990 in water enclosures as well as in the Zingster Strom (Dar beta -Zingster bodden area). For this survey, physical planktological and microbiological variables were determined. The aim of this study was the analysis of the structures and dynamic processes in different marine pelagic systems. The relationship of bacterial abundance and biomass to other pelagic components and the energy flow mediated by bacteria were of the main interest. Additionally, the method for the determination of particulate DNA (pDNA) concentrations, developed by Paul & Myers (1982), was optimized in this study. The results of pDNA measurements were correlated with the abundance of bacteria and further pelagic components. Some aspects of this study concerned the seasonal development of pelagic structures, microbial processes within a stratified water body, 'bottom up' control, diurnal biological processes and the influence of hydrographic features (eddies) on auto- and heterotrophic pelagic components.
AN: 2989454
760 of 1521
TI: Dissolved trace metals in the southwestern Indian Ocean.
AU: Morley,-N.H.; Statham,-P.J.; Burton,-J.D.
AF: Dep. Oceanogr., University, Highfield, Southampton SO9 5NH, UK
SO: DEEP-SEA-RES.-1-OCEANOGR.-RES.-PAP.. 1993. vol. 40, no. 5, pp. 1043-1062
LA: English
ER: M (Marine)
AB: Dissolved trace metal concentrations are reported for a section in the southwestern Indian Ocean, extending from 7 to 27 degree S around the 56 degree E meridian. Overall distributions conform to those found in other oceans, with Cd, Cu, Ni and Zn showing recycled, or nutrient-like, behaviour, whereas Mn is enriched in the mixed layer relative to deep water. Deep-water concentrations of the recycled elements are intermediate between those for the North Atlantic and North Pacific Oceans, as would be expected from known patterns of deep-ocean circulation. For Cd and Zn, depletion in the surface layer approaches detection limits while for Cu and Ni significant near-surface concentrations (0.9 and 2.1 nM, respectively) are found. Relationships between the concentrations of metals and nutrients are similar to those described in the literature for the recycled metals for other regions, although significant variations exist from ocean to ocean. Maximum manganese concentrations in the upper water column are about or below 1 nM, as expected for a region remote from continental sources of airborne particulate material. Minor variations in maximum concentration with latitude are evident as a result of the complex geochemistry of this element. Deep water manganese concentrations are uniformly low, showing no evidence for benthic or hydrothermal sources.
AN: 2989125
761 of 1521
TI: Mathematical model for global ecological investigations.
AU: Krapivin,-V.F.
AF: Inst. Radio Eng. and Electron., Russian Acad. Sci., Fryazino, Vvedenskogo 1, Moscow Reg. 141120, Russia
SO: ECOL.-MODEL. 1993. vol. 67, no. 2-4, pp. 103-127
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The paper gives a schematic description of a mathematical model of the biosphere (MMB) representing interaction of the atmosphere with the land and ocean ecosystems. The model comprises blocks describing biogeochemical cycles of carbon, nitrogen, sulphur, phosphorus and oxygen; global hydrologic balance in liquid, gaseous and solid phases; productivity of soil-plant formations with 30 types defined; photosynthesis in ocean ecosystems taking into account its depth and surface inhomogeneity; demographic processes and anthropogenic changes. The model is designed to be connected to a global climate model. Examples of using the MMB for estimating the state of the biosphere and its subsystems are presented.
AN: 2985529
762 of 1521
TI: Production of nutrients and their contribution to runoff water according to the various uses of the land in the Sierra de Guadarrama (Madrid).
AU: Pareja,-B.L.; Artola,-C.G.; Garcia,-P.G.; Vera,-F.L.
AF: Univ. Coll. San Pablo, C.E.U., Madrid, Spain
SO: J.-ENVIRON.-HYDROL. 1993. vol. 1, no. 2, pp. 35-42
LA: English
ER: F (Freshwater)
AB: The importance that runoff plays in the transport of nutrients was studied in sub-basins that have undergone little alteration and where pressure from man and point pollution do not disguise the influence of the soil. For the purpose of this study sub-basins which are homogeneous in lithology and vegetation were chosen. These sub-basins are located within the watershed of the Santillana Reservoir. Quantitative relations between the variations in runoff and export coefficients which represent the production of nutrients at the level of the basin, were established beforehand. Conclusions derived from the results of the geobiochemical behavior of nitrogen and phosphorus related to our area of study are included.
AN: 2985122
763 of 1521
TI: Carbon and nitrogen budgets of the Arabian Sea.
AU: Somasundar,-K.; Rajendran,-A.; Dileep-Kumar,-M.; Sen-Gupta,-R.
AF: Natl. Inst. Oceanogr., Dona Paula, Goa 403 004, India
SO: MAR.-CHEM. 1990. vol. 30, no. 4, pp. 363-377
LA: English
ER: M (Marine)
AB: From the available data, carbon and nitrogen budgets have been estimated for the Arabian Sea (0-25 degree N, 50-80 degree E), taking into consideration the possible sources of fluxes. By our model calculations the annual fluxes into and out of the Arabian Sea were estimated to be 446 and 530 trillion grams (Tg) for carbon, and 8.06 and 3.60 Tg for nitrogen, respectively. The carbon budget was found to be negatively balanced by 84 Tg/year. A possible source to compensate for this deficit could be from the northward movement of Antarctic Bottom Water in the bottom layers, which are probably enriched with anthropogenic carbon dioxide. The percentage loss of carbon (14.0%) to the atmosphere was much lower than that of nitrogen (56.9%). Out of the total amount of denitrified nitrogen (29.5 Tg) only similar to 7% was lost to the atmosphere. This model suggests that similar to 6 Tg N/year of denitrified nitrogen of the world's oceans could be liberated to the atmosphere through the surface layer of denitrified areas. A quantitative assessment has been made to account for the excess of nitrogen that could result from N sub(2) fixation by extensive blooms of Trichodesmium) in the Arabian Sea. Based on the standing crop and net outfluxes, estimated residence times were similar to 944 and 4.04 x 10 super(4) years for carbon and nitrogen, respectively, in the Arabian Sea.
AN: 2985041
764 of 1521
TI: Nutrient chemistry of the water column of Lake Tanganyika.
AU: Edmond,-J.M.; Stallard,-R.F.; Craig,-H.; Craig,-V.; Weiss,-R.F.; Coulter,-G.W.
AF: Dep. Earth, Atmos. Planet. Sci., E34-201, MIT, Cambridge, MA 02139, USA
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 4, pp. 725-738
LA: English
ER: F (Freshwater)
AB: Lake Tanganyika shows permanent thermal stratification with deep-water temperatures that have been stable over the period of observation (since 1939). The lake is anoxic below similar to 150-m depth. In general the nutrients show Redfield behavior save in the deep waters of the northern basin where large excesses of phosphate and ammonia are present. Bacterial disproportionation of organic material probably plays an important role in producing these excesses. Inorganic desorption from fluvial detritus is also a possible source of excess phosphate in deep waters. The oxic-anoxic boundary at similar to 150 m is a sink for all forms of fixed nitrogen. Thus the nutrient budget to the lake probably involves fixation of nitrogen in the surface layer in addition to substantial inputs from rainfall and runoff, with the phosphate supplied by vertical mixing. Because these processes are in approximate balance under present conditions, the productivity of the lake must be very sensitive to changes in climatic forcing.
AN: 2983408
765 of 1521
TI: Partitioning of the nitrogen stock in the vicinity of a Fijian seagrass bed dominated by Syringodium isoetifolium (Ascherson) Dandy.
AU: Yamamuro,-M.; Koike,-I.; Iizumi,-H.
AF: Mar. Geol. Dep., Geol. Surv. Japan, Higashi 1-1-3 Tsukuba, Ibaraki 305, Japan
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1993. vol. 44, no. 1, pp. 101-115
NT: Special issue: Tropical Seagrass Ecosystems.
LA: English
ER: M (Marine)
AB: Partitioning of the nitrogen stock in a Fijian seagrass bed dominated by Syringodium isoetifolium (Ascherson) Dandy and in an adjacent area bare of macrophytic vegetation was assessed to evaluate the effect of the presence of seagrass on coral sediment. Concentrations of major nutrients, such as nitrogen and phosphate, were as low in the water column at the seagrass bed and the bare area as they were in the open ocean. Concentrations of ammonium and dissolved organic nitrogen, however, were higher in the water within the seagrass canopy than they were in other waters. In sediments at the seagrass bed and the bare area, interstitial nitrogen, such as nitrate and dissolved organic nitrogen, was a minor component of the total nitrogen (0.3-0.05%). On the other hand, concentrations of total organic nitrogen in seagrass-bed sediment (about 70% of which was in the form of amorphous organic nitrogen and the rest of which came from living and dead seagrass) were more than three times higher than those in bare-area sediment. Concentrations of organic carbon from amorphous organic materials in seagrass-bed sediment showed no large change with depth, resulting in an apparent decrease in the carbon/nitrogen atom ratio from 60 to 10. These results suggest some mechanisms to minimize the loss of nitrogen stock from the sediment of tropical seagrass beds.
AN: 2980187
766 of 1521
TI: Carbon inputs and biogeochemical processes at the halocline in a stratified estuary: Krka River, Yugoslavia.
AU: Cauwet,-G.
AF: Lab. Sedimentol. Geochim. Mar., Unite Assoc. CNRS No. 715, Univ. Perpignan, France
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: PHYSICAL,-CHEMICAL-AND-BIOLOGICAL-PROCESSES-IN-STRATIFIED-ESTUARIES. Zutic,-V.-ed. 1991. vol. 32, no. 2-4 pp. 269-283
ST: MAR.-CHEM. vol. 32, no. 2-4
LA: English
ER: M (Marine); B (Brackish)
AB: Suspended matter, particulate and dissolved organic carbon and dissolved inorganic carbon were measured seasonally from 1987 to 1989 in the Krka Estuary. Carbon inputs by the river are low, because of the small river flow and the low content of suspended matter of its water. The permanent stratification of the estuary creates an unusual environment, with a very sharp salinity gradient at the freshwater-seawater interface. The accumulation of particulate organic carbon at the interface and the production of dissolved organic carbon suggest that an enhanced biological activity influences the organic matter budget.
AN: 2970954
767 of 1521
TI: Estuarine transformation of organic matter: Single coalescence events of estuarine surface active particles.
AU: Svetlicic,-V.; Zutic,-V.; Tomaic,-J.
AF: Rudjer Boskovic Inst., Cent. Mar. Res. Zagreb, P.O. Box 1016, 41001 Zagreb, Croatia
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: PHYSICAL,-CHEMICAL-AND-BIOLOGICAL-PROCESSES-IN-STRATIFIED-ESTUARIES. Zutic,-V.-ed. 1991. vol. 32, no. 2-4 pp. 253-267
ST: MAR.-CHEM. vol. 32, no. 2-4
LA: English
ER: M (Marine); B (Brackish)
AB: Individual surface-active particles (SAP) in aqueous environmental samples can be characterized through their coalescence at a model hydrophobic interface. Each coalescence event is recorded as an electrical signal. As the electrical signal is a current transient (time on a millisecond scale), the sequence of fast processes leading to the formation of a condensed film can be studied from the moment of first attachment at the interface. In the stratified Krka Estuary, SAP are present in maximum concentrations (10 super(7)-5x10 super(8) particles/l in the size range > 1 mu m) at the halocline (freshwater-seawater interface). This highly surface-active fraction of particulate organic matter can be viewed as oily droplets. SAP are fluid, and are readily transformed at interfaces to films of molecular thickness (surface area per particle is in the range 10 super(-5)-10 super(-2) cm super(2)). Comparison of response of individual SAP with model particles, and the frequency of their appearance in estuarine samples, shows that a majority of estuarine SAP has, in terms of viscosity and film permeability, the properties of oleic acid. A significant fraction of SAP have more rigid structures, comparable to oleic acid+cholesterol model particles. A small fraction (< 1%) behaves as phytoplankton cells with fluid outer membranes. We have also presented evidence for a strong interaction between elemental mercury and SAP, which is not sensitive to the molecular structure of the organic phase. The puzzling accumulation of mercury at the halocline of the Krka Estuary may be regarded as the result of interaction of elemental mercury with SAP.
AN: 2970931
768 of 1521
TI: Variations in the chemical lability of iron in estuarine, coastal and shelf waters and its implications for phytoplankton.
AU: Wells,-M.L.; Mayer,-L.M.
AF: Dep. Oceanogr., Univ. Maine, Ira C. Darling Cent., Walpole, ME 04573, USA
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: PHYSICAL,-CHEMICAL-AND-BIOLOGICAL-PROCESSES-IN-STRATIFIED-ESTUARIES. Zutic,-V.-ed. 1991. vol. 32, no. 2-4 pp. 195-210
ST: MAR.-CHEM. vol. 32, no. 2-4
LA: English
ER: M (Marine); B (Brackish)
AB: The relationship between total and chemically labile Fe has been studied in estuarine, coastal and shelf waters of the Gulf of Maine, U.S.A. Measurements of the labile fraction of total Fe, defined by complexation with 8-hydroxyquinoline in 1 h, correlate with the availability of Fe to marine phytoplankton and therefore can be used to estimate Fe availability in seawater. The results show that the relative lability (= labile/total) of Fe in seawater varied both spatially and temporally from near-zero to 100%. Although particulate Fe (> 0.45 mu m) was generally less labile than dissolved Fe (< 0.45 mu m), the particulate fraction often contributed substantially to labile Fe concentrations overall. Conversely, as much as 75% of "dissolved" Fe was non-labile, and therefore was probably not available to phytoplankton. In seawater/river-water mixing experiments, aggregation diminished the relative lability of Fe by similar to 30%, even though much of it remained in the "dissolved" fraction. Considering phytoplankton nutrition, these results demonstrate that equating dissolving Fe concentrations with "available" metal can be misleading. Furthermore, the large variability observed in the labile proportion of total Fe in seawater indicates that Fe availability to phytoplankton cannot be estimated by applying fixed lability-ratios to total Fe concentrations.
AN: 2970783
769 of 1521
TI: Trace metal-nutrient relationships in estuaries.
AU: Windom,-H.; Byrd,-J.; Smith,-R.,Jr.; Hungspreugs,-M.; Dharmvanij,-S.; Thumtrakul,-W.; Yeats,-P.
AF: Skidaway Inst. Oceanogr., P.O. Box 13687, Savannah, GA 31416, USA
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: PHYSICAL,-CHEMICAL-AND-BIOLOGICAL-PROCESSES-IN-STRATIFIED-ESTUARIES. Zutic,-V.-ed. 1991. vol. 32, no. 2-4 pp. 177-194
ST: MAR.-CHEM. vol. 32, no. 2-4
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The distributions of cadmium, copper, zinc and nutrients were determined in the estuaries of the Medway (Canada), Savannah (U.S.A.) and Maeklong (Thailand) rivers to assess the influence of biological processes on the trace metal estuarine behavior. These metals were chosen because they show nutrient-type behavior in the ocean. Three types of metal-nutrient relationships were considered: those resulting from biological uptake, regeneration and abiotic processes. Biological uptake was not observed to be an important process affecting trace metal behavior in estuaries. Biological regeneration appears to be an important process only for cadmium, based on its relationship with phosphate or nitrogen. The enrichment of nickel in estuarine waters is greater than can be explained by regeneration of organic material, which suggests that abiotic processes are more important. Zinc is generally removed from solution during estuarine mixing, perhaps associated with iron removal. Copper covaries closely with silica and is suggested to be the result of additional weathering of silicate minerals within the estuarine environment. Results from all the estuarine studies suggest that copper and silica are not fractionated during weathering and transport from the continents to the ocean. Iron-phosphate covariance in the Savannah Estuary is attributed to their simultaneous removal by the formation of FePO sub(4).
AN: 2970746
770 of 1521
TI: Physical, chemical and biological processes in stratified estuaries.
AU: Zutic,-V.-(ed.)
CO: 1. Int. Symp. on Small Estuaries, Primosten (Yugoslavia), 21-27 May 1989
SO: MAR.-CHEM. 1991. vol. 32, no. 2-4, pp. 111-385
LA: English
ER: M (Marine); B (Brackish)
AB: Except for their physical scale, small estuaries are as complex as large ones; they contain practically the same unknowns as the large estuaries. However, their small physical scale offers the advantage to perform basic and applied research more efficiently. Furthermore, small estuaries are important per se being demographically and economically attractive, important and ecologically endangered. The Symposium was brought about by the intention to organize a workshop of the French-Yugoslav research group working on the Krka Estuary, a small estuary on the east coast of the Adriatic Sea. The characteristics of this estuary, which in 1985 was declared a national park, are: it is karstic; the terrigenous load and particle content are extremely low; it is highly stratified with sharp and visible fresh water/seawater interface; in its upper and middle reach it is still one of the most pristine estuaries in Europe. Recent multidisciplinary research on the Krka Estuary has resulted in discoveries of a few new phenomena of the fresh water/seawater interface. While physical, chemical and biological processes are better understood at air/water and sediment/water interfaces, processes at the fresh water/seawater interface have only recently attracted attention of the researchers.
AN: 2970629
771 of 1521
TI: Evidence of recent lead pollution in Northeast Atlantic sediments.
AU: Tian,-Rucheng
AF: Inst. Estuarine and Coastal Res., East China Norm. Univ., Shanghai 200000, People's Rep. China
CO: 4. Chinese Oceanological and Limnological Science Conf. Qingdao, Shandong (People's Rep. China) (nd)
SO: PROCEEDINGS-OF-THE-4th-CHINESE-OCEANOLOGICAL-AND-LIMNOLOGICAL-SCIENCE-CONFERENCE. DISICI-ZHONGGUO-HAIYANG-HUZHAO-KEXUE-HUIYI-LUNWENJI. Chinese-Soc.-of-Oceanology-and-Limnology,-Beijing-China BEIJING-CHINA SCIENCE-PRESS 1991. pp. 122-127
LA: Chinese
ER: M (Marine)
AB: It is now recognized that the biogeochemical cycle of lead in the open ocean is significantly perturbed by anthropogenic pollution. We collected seven cores in the Northeast Atlantic with an interface-corer of IGFA (France) in 1985. Atomic Absorption Spectrometry and Cathodic Stripping Voltammetry were used to determine lead concentration in sediments. Meanwhile one core was analyzed by sequential attaque to determine lead distribution in different forms of existence. Our results show that lead content is much higher in surficial sediments than below. The depth of sediments rich in lead is less than 1 cm in most cores and only 2 to 3 mm in cores 5 and 6. Sequential attaque analyses show that enrichment of lead in surficial sediments is caused by increase of labile Pb while conservative lead content has no evident changes.
AN: 2967132
772 of 1521
TI: ISHTAR, the project: An overview of Inner Shelf Transfer and Recycling in the Bering and Chukchi seas.
AU: McRoy,-C.P.
AF: Inst. Mar. Sci., Univ. Alaska, Fairbanks, AK 99775, USA
SO: CONT.-SHELF-RES. 1993. vol. 13, no. 5-6, pp. 473-479
LA: English
ER: M (Marine)
AB: ISHTAR was designed to study the impact of interannual variability of physical forcing on the cycle of carbon and nutrients in the shelf waters of the northern Bering and Chukchi seas. Anadyr Water is the nutrient source for high seasonal production in all trophic levels. Variations in transport of this water lead to variations in carbon fixation, deposition, and mineralization.
AN: 2962496
773 of 1521
TI: Rates of nitrification, distribution of nitrifying bacteria and inorganic N fluxes in northern Bering-Chukchi shelf sediments.
AU: Henriksen,-K.; Blackburn,-T.H.; Lomstein,-B.A.; McRoy,-C.P.
AF: Inst. Environ. Eng., Univ. Aalborg, Sohngaardsholmsvej 57, 9000 Aalborg, Denmark
SO: CONT.-SHELF-RES. 1993. vol. 13, no. 5-6, pp. 629-651
LA: English
ER: M (Marine)
AB: Spatial distribution of sediment nitrification rates and fluxes of ammonium and nitrate were measured in shelf sediments of the northern Bering and Chukchi seas. The sediments could be divided into three main areas depending on macrofaunal activity and input of organic nitrogen. Sediments underlying the highly productive Bering Shelf-Anadyr water (BSAS) were characterized by a high macrofaunal biomass and a high input of nitrogen-rich organic material. Tube-dwelling amphipods dominated in the sandy sediments of the northern Bering Sea, while bivalves dominated in the fine textured sediments of the Chukchi Sea. Sediments underlying the low productive Alaska Coastal Water (ACS) were characterized by low macrofaunal biomass and an input of lower quality organic material. Generally nitrification rates and nutrification potentials (NP) were highest in BASA and lower in ACS. Nitrification rates of surface sediment, calculated from NP, accounted for 90% of the measured rates in ACS, but only 35-75% in BSAS. These data together with the distribution patterns of NP and pore water nitrate profiles implied, that most sediment nitrification was confined to the sediment surface in ACS and in BSAS bivalve sediments, while most sediment nitrification took place in the ventilated burrow of BSAS amphipod sediments. The NH sub(4)@)u+ efflux was five-fold greater from BSAS compared to ACS, whereas the estimated sediment net NH sub(4) super(+) production was three-fold greater. The increase in NH sub(4)@)u+ efflux relative to net NH sub(4)@)u+ production could mostly be attributed to macrofaunal excretion. The NO sub(3)@)u- flux between sediment and water column was correlated with NO sub(3)@)u- concentrations in the bottom water. At concentrations higher than 10 mu M NO sub(3)@)u-, the flux was directed into the sediment and at lower concentrations out of the sediment. Spatial distribution of high bottom water NO sub(3)@)u- concentrations correlated with high NH sub(4)@)u+ fluxes out of the sediment. This resulted in a lower net efflux of inorganic nitrogen from these sediments.
AN: 2962346
774 of 1521
TI: Mediation of sulfur speciation by a Black Sea facultative anaerobe.
AU: Perry,-K.A.; Kostka,-J.E.; Luther,-G.W.,III; Nealson,-K.H.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: SCIENCE-WASH.. 1993. vol. 259, no. 5096, pp. 801-803
LA: English
AB: Shewanella putrefaciens , a respiratory facultative anaerobe isolated from the Black Sea, can reduce thiosulfate, sulfite, and elemental sulfur to sulfide readily and quantitatively. This widespread and anaerobically versatile microorganism, which is incapable of reducing sulfate, uses oxidized sulfur intermediates as electron acceptors during the respiratory oxidation of organic matter. Because of its widespread distribution and abundance, it may play a significant role in sulfur and trace metal cycling in the Black Sea and in other marine and freshwater anaerobic environments.
AN: 2962345
775 of 1521
TI: Seasonal and diel variation in the open ocean concentration of marine snow aggregates.
AU: Lampitt,-R.S.; Hillier,-W.R.; Challenor,-P.G.
AF: Inst. Oceanogr. Sci., Deacon Lab., Wormley, Godalming, Surrey GU8 5UB, UK
SO: NATURE. 1993. vol. 362, no. 6422, pp. 737-739
LA: English
ER: M (Marine)
AB: Marine snow, generally defined as aggregated particles of diameter greater than 0.5 mm, is thought to play an important role in oceanic biogeochemical cycles. Recent studies have focused on its unusual physical, biological and chemical properties but its temporal variability has received scant attention. The authors report observations of the abundance, volume concentration and size distribution of marine snow over a five-month period at a single site in the Northern Atlantic. At a depth of 270 m, marine snow particles demonstrated strong seasonal and diel variability. Volume concentrations in spring were about 20 times those in summer and autumn with late morning concentrations up to three times higher than at other times of the day. Our results suggest that the marine snow forms as a result of highly dynamic interactions in the particle pool. We believe that the mid-water biota and their migratory behaviour are responsible for the diel variability; they are therefore likely to have a significant influence on marine snow concentrations and hence on open-ocean material flux.
AN: 2960207
776 of 1521
TI: Spatial distribution, temporal sequence, and seasonal cycle of phytoplankton in reservoirs: Limiting and controlling factors.
OT: Distribuicao espacial, sequeencia temporal e ciclo sazonal do fitoplancton em represas: Fatores limitantes e controladores
AU: Tundisi,-J.G.
AF: Dep. Hidraul. e Saneamento Esc. Eng. Sao Carlos, Univ. Sao Carlos, Sao Carlos, SP, Brazil
SO: REV.-BRAS.-BIOL. 1990. vol. 50, no. 4, pp. 937-955
LA: Portuguese
ER: F (Freshwater)
AB: Artificial reservoirs are subjected not only to the climatological forcing functions that control or limit the seasonal cycle of phytoplankton and the biogeochemical cycles in aquatic ecosystems. The operation system produces an horizontal and unidirectional flux; these and the changing retention times are key factors that establish basic mechanisms for phytoplankton spatial distribution and succession. Physical forcing functions are thus fundamental in reservoirs. Pulse effects produced by climatological factors (precipitation, wind) coupled with water flux and discharge are key factors in the distribution of phytoplankton in time, and space. Spatial scales, include responses to changing turbulence conditions, patchiness associated with microscales in nutrient and temperature/conductivity/density characteristics of the water masses. The manipulation of these physical processes can be a valuable tool in the control of phytoplankton succession in reservoirs. Analysis of long term series of data can provide conditions for prognosis of the succession, distribution patterns, and interference in the ecosystem. Sampling programs have to be adapted to temporal/spatial scales of fluctuations and to microstructures in the systems. Specific examples for some key Brazilian reservoirs are given: the Lobo/Broa ecosystem-shallow meso oligotrophic - and the Barra Bonita reservoir - deeper eutrophic.
AN: 2959472
777 of 1521
TI: Organic matter in suspension and bottom sediments over the Guinea shelf.
OT: Organicheskoe veshchestvo vo vzvesi i donnykh otlozheniyakh shel'fa Gvinei
AU: Bezborodov,-A.A.; Burlakova,-Z.P.; Emel'-yanova,-O.V.
AF: MGI AN Ukr.S.S.R., Sevastopol', Ukraine
SO: EHKOL.-MORYA. 1991. no. 39, pp. 42-46
LA: Russian
ER: M (Marine)
AB: The patterns of suspended organic matter distribution over the shelf of Guinea during dry and wet seasons are considered and charts showing the distribution of organic carbon in the shelf sediments are provided. Effect of frontal upwelling zones and the tidal zone on the concentration and dispersion of organic matter in water and sediments is discussed.
AN: 2955517
778 of 1521
TI: Influence of temperature and substrate concentration on bacterial growth yield in Seine River water batch cultures.
AU: Barillier,-A.; Garnier,-J.
AF: CEMAGREF, 14 Ave. Saint-Mande, 75012 Paris, France
SO: APPL.-ENVIRON.-MICROBIOL. 1993. vol. 59, no. 5, pp. 1678-1682
LA: English
ER: F (Freshwater)
AB: The growth of natural bacterial assemblages was monitored in 3-liter reactors under various temperature and substrate concentration conditions. The oxygen concentration was continuously monitored, and subsamples were taken at short time intervals to determine bacterial number and biomass. The rate of bacterial mortality was also determined. Bacterial growth yield was calculated as the ratio of net production (increase in biomass corrected for mortality) to gross production (net production plus oxygen consumption expressed in carbon units). Averaging 33%, the growth yield did not show any trend with temperatures in the range of 8 to 25 degree C but increased with the concentration of dissolved organic carbon in the range of 2 to 12 mg of C/liter.
AN: 2953848
779 of 1521
TI: Laser microprobe mass analysis of Amazon Basin aerosols.
AU: Wouters,-L.; Hagedoren,-S.; Dierck,-I.; Artaxo,-P.; Van-Grieken,-R.
AF: Univ. Antwerp (UIA), Universiteitsplein 1, B-2610 Antwerp-Wilrijk, Belgium
SO: ATMOS.-ENVIRON.,-PART-A. 1993. vol. 27A, no. 5, pp. 661-668
LA: English
ER: F (Freshwater)
AB: Individual aerosol particles sampled over the Amazon Basin, Brazil, were analysed using laser microprobe mass analysis (LAMMA). Spectra are complex due to the high organic content of the samples. Phosphate was found to be concentrated largely in one particle type, which was only detected in the dry season samples. This points to a biomass burning origin or at least to a season-related vegetative aerosol production mechanism. The most abundant particle type, most likely originating from a vegetation source, can be described as a mixture of different salts and organic fragments.
AN: 2953004
780 of 1521
TI: Variations in aqueous sulfate concentrations at Panola Mountain, Georgia.
AU: Shanley,-J.B.; Peters,-N.E.
AF: U.S. Geol. Surv., P.O. Box 628, Monpelier, VT 05601, USA
SO: J.-HYDROL.-AMST.. 1993. vol. 146, no. 1-4, pp. 361-382
LA: English
ER: F (Freshwater)
AB: Aqueous sulfate concentrations were measured in incident precipitation, canopy throughfall, stemflow, soil water, groundwater, and streamwater at three locations in a 41 ha forested watershed at Panola Mountain State Park in the Georgia Piedmont. To evaluate the variations in sulfate concentrations, sampling intensity was increased during storms by automated collection of surface water and by incremental subsampling of rainfall, throughfall, and soil solution. Canopy throughfall, stemflow, and runoff from a bedrock outcrop in the watershed headwaters were enriched in sulfate relative to incident precipitation due to washoff of dry deposition that accumulated between storms. Soil waters collected from zero-tension lysimeters at 15 cm and 50 cm below land surface also were enriched in sulfate relative to precipitation, groundwater and streamwater. Sulfate concentrations in groundwater and in streamwater at base flow varied in an annual sinusoidal pattern with winter maxima and summer minima. Stream discharge and groundwater levels varied in a similar annual pattern in phase with the sulfate concentrations. The temporal variability of sulfate concentrations at most groundwater sites was small relative to the spatial variability among groundwater sites. Streamwater sulfate concentrations during base flow were controlled by low-sulfate groundwater discharge. As flow increased, an increasing proportion of shallow, high-sulfate groundwater and soil water contributed to streamflow. The dominant control on stream sulfate concentration shifted from sulfate retention by adsorption in the mineral soil at base flow to mobilization of sulfate from the upper, organic-rich horizons of the soil at high flow.
AN: 2951279
781 of 1521
TI: Mercury speciation in open ocean waters.
AU: Mason,-R.P.; Fitzgerald,-W.F.
AF: Dep. Mar. Sci., Univ. Connecticut, Avery Point, Groton, CT 06340, USA
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 779-789
LA: English
ER: M (Marine)
AB: Vital to our understanding of the biogeochemical cycling of Hg and the origin of the enhanced monomethylmercury (MMHg) concentrations in biota is knowledge of the sources, behaviour and fate of methylated Hg species in natural waters. Methylated Hg species, dissolved gaseous and reactive mercury were measured in the equatorial Pacific Ocean in early 1990. Both dimethylmercury (DMHg) and MMHg were found in the subthermocline waters of the equatorial Pacific Ocean. Maxima in alkylmercury species in the O sub(2) minimum region coincided with a decrease in reactive mercury. A significant inverse correlation between DMHg, and MMHg, concentration and O sub(2) content was observed. A maximum in reactive mercury was observed in the region of the thermocline, with similar concentrations in the surface and deeper waters.
AN: 2949032
782 of 1521
TI: Variations in mercury deposition to Antarctica over the past 34,000 years.
AU: Vandal,-G.M.; Fitzgerald,-W.F.; Boutron,-C.F.; Candelone,-J.-P.
AF: Dep. Mar. Sci., Univ. Connecticut, Avery Point, Groton, CT 06340, USA
SO: NATURE. 1993. vol. 362, no. 6421, pp. 621-623
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: POLAR ice contains a valuable record of past atmospheric mercury deposition, which can provide information about both the natural biogeochemical cycling of this toxic trace metal and the impact of recent anthropogenic emissions. But existing studies of mercury in polar ice and snow cores suffer from sample contamination and inadequate analytical procedures. Here we report measurements of mercury concentrations spanning the past 34,000 years from the Dome C ice core, Antarctica, using the stringent trace-metal clean protocols developed by Patterson and co-workers. Although this record does not extend into the industrial period, it provides an important baseline for future attempts to identify anthropogenic mercury in Antarctic ice and snow. We find that mercury concentrations were strikingly elevated during the last glacial maximum (18,000 years ago), when oceanic productivity may have been higher than it is today. As oceanic mercury emission is correlated with productivity, we suggest that this was the principal pre-industrial source of mercury to Antarctica; mercury concentrations in Antarctic ice might therefore serve as a palaeoproductivity indicator for the more distant past.
AN: 2941375
783 of 1521
TI: Carbon dynamics and sources in the Parana River.
AU: Depetris,-P.J.; Kempe,-S.
AF: SCOPE/UNEP Int. Carbon Unit, Inst. Biogeochem. und Meereschem., Univ. Hamburg, Bundesstr. 55, 2000 Hamburg 13, FRG
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 2, pp. 382-395
LA: English
ER: F (Freshwater)
AB: The Parana River was sampled and analyzed for carbon and mineral concentrations at the Parana-Santa Fe (Argentina) cross-section ( similar to 600 km above the mouth) between March 1981 and November 1984. Within this period, the Parana was affected by an extraordinary flood caused by the 1982 El Nino/Southern Oscillation (ENSO) climatic anomaly. Under such conditions, with a flow 75% higher than the long-term mean, the river exported a total organic C (TOC) load of 8.43 Tg/yr (3.0 g m super(-2)/yr) of which 89% was accounted for by dissolved organic C (DOC) and the remainder by particulate organic C (POC). Under normal hydrological conditions, however, the Parana has a TOC load that is roughly half of that determined during the ENSO-triggered flood (4.43 Tg/yr, 1.6 g m super(-2)/yr), but with a very different DOC:POC ratio (63:37). In July-August 1985 the Parana was sampled along a reach of over 1,300 km. At the time of sampling, the Paraguay River supplied similar to 68% of the POC load, 59% of the labile particulate load (LPOC), and 71% of the DOC entering the middle reach of the Parana. Carbohydrates in LPOC appear to become more abundant that amino acids in the lower reaches, probably due a significant input from the floodplain of the Parana.
AN: 2940309
784 of 1521
TI: Uranium behavior in a permanently anoxic fjord: Microbial control?.
AU: McKee,-B.A.
AF: Louisiana Univ. Mar. Cent., Louisiana Univ. Mar. Consortium, 8124 Highw. 56, Cocodrie, LA 70344, USA
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 2, pp. 408-414
LA: English
ER: M (Marine)
AB: Uranium contamination of groundwater resulting from U mining activities and the leak-age of nuclear waste from storage facilities is a growing concern. In Framvaren Fjord (southern Norway), dissolved super(238)U concentrations at the bacterial maximum layer (24 m), which is situated a few meters below the oxic-anoxic (i.e. oxygen-hydrogen sulfide) interface (18 m), are observed to be similar to 60% lower than concentrations above and below this depth. Removal of U occurs well below the depth at which Fe and Mn oxyhydroxides are precipitated and under conditions inconsistent with abiological reduction of soluble U(VI) to particle-reactive U(IV). Our observations suggest that the microbial population in the anoxic waters near the O sub(2)-H sub(2)S interface in the fjord exerts an effective control on the aquatic biogeochemistry of U in this environment.
AN: 2940272
785 of 1521
TI: Fish foraging behavior changes plankton-nutrient relations in laboratory microcosms.
AU: Novales-Flamarique,-I.; Griesbach,-S.; Parent,-M.; Cattaneo,-A.; Peters,-R.H.
AF: Dep. Biol., McGill Univ., Montreal, PQ, Canada
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 2, pp. 290-298
LA: English
ER: F (Freshwater)
AB: To demonstrate that the effects of higher trophic elements on plankton in laboratory aquaria are not simple top-down or bottom-up processes, we measured phosphorus and chlorophyll concentrations in replicated month-old aquaria undergoing one of five permutations involving three fish species, Daphnia pulex , and algae. Goldfish (Carassius auratus ) extirpated the Daphnia and produced the highest observed algal and nutrient levels. Daphnia persisted with armored catfish (Plecostomus hypostomus ) but algal levels were still high, even though total P concentrations of the water were lower. Angelfish (Pterophyllum scalare ) cropped all the Daphnia , but only moderate levels of algae resulted, apparently because these fish regenerate sedimented nutrients less effectively. Aquaria with neither fish nor Daphnia supported even less algae, although total P concentration was not reduced. Finally, the water in aquaria with Daphnia , but no fish, had the lowest levels of both chlorophyll and total P. These gross changes were accompanied by shifts between the two dominant algal general, seemingly because higher levels of nutrient regeneration favor Scenedesmus over Monoraphidium . Apparently, higher trophic elements affect lower ones directly, from above by modifying predation pressure and from below by changing the quantity and quality of regenerated nutrients, and indirectly by modulating competition within the plankton and between plankton and periphyton.
AN: 2940230
786 of 1521
TI: Rapid oxygen cycling in Trichodesmium thiebautii .
AU: Kana,-T.M.
AF: Horn Point Environ. Lab., P.O. Box 775, Cambridge, MD 21613, USA
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 1, pp. 18-24
LA: English
ER: M (Marine)
AB: Oxygen uptake and evolution were measured in Trichodesmium thiebautii trichomes with super(18)O membrane inlet mass spectrometry. Samples were collected in the vicinity of the Bahamas Islands and eastern Caribbean Sea. Trichodesmium exhibited high rates of oxygen uptake in the dark and in the light compared with previously studied cyanobacteria. Oxygen uptake in the dark averaged 23% of the maximum gross oxygen evolution rate and was suppressed minimally at low irradiances or after the addition of cyanide. Oxygen uptake in light increased between 50 and 200 mu Einst m super(-2)/s and was inhibited by 3-(3,4-)-dichlorophenyl)-1,1-dimethylurea (DCMU), indicating Mehler reaction activity. I estimate that 48% of the total photosynthetic linear electron flow went to oxygen reduction at moderate but nonsaturating irradiances. Light compensation points ranged from 50 to 300 mu Einst m super(-2)/s with values highest for midday samples. Rapid oxygen cycling may contribute to the protection of nitrogenase by reducing the oxygen tension within the cell or colony during oxygenic photosynthesis and by providing a mechanism (pseudocyclic photophosphorylation) for generating excess ATP for nitrogen fixation.
AN: 2940008
787 of 1521
TI: The influence of light intensity on dimethylsulfide production by a marine diatom.
AU: Vetter,-Y.-A.; Sharp,-J.H.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: LIMNOL.-OCEANOGR. 1993. vol. 38, no. 2, pp. 419-425
LA: English
ER: M (Marine)
AB: The influence of light intensity on the production of the gas dimethylsulfide (DMS) by Skeletonema costatum was studied in batch cultures. Culture pairs were grown under identical conditions except for light intensity. Cultures displayed a spike of dissolved DMS following inoculation and an increase in dissolved DMS during log phase and stationary phase. These increases were slower and less pronounced under reduced illumination. DMS production per cell declined throughout phase under reduced light, but remained constant throughout log phase under full illumination. The total mass of DMS produced under reduced light was less than half that produced under full illumination.
AN: 2939742
788 of 1521
TI: NOGAP B.6; Volume 9: Hydrocarbon determinations; Mackenzie River and Beaufort Sea
AU: Yunker,-M.B.; McLaughlin,-F.A.; Fowler,-B.R.; Brooks,-G.; Chiddell,-G.; Hamilton,-C.; Macdonald,-R.W.
CA: Institute of Ocean Sciences, Patricia Bay, Sidney, BC (Canada)
SO: CAN.-DATA-REP.-HYDROGR.-OCEAN-SCI. 1992 no. 60, 291 pp
NT: NTIS-Accession Number: MIC-93-02857/4.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: As part of the NOGAP B.6 program, with major objectives to determine hydrocarbon pathways and primary productivity of the waters overlying the Mackenzie shelf, the authors collected hydrocarbon samples in the Mackenzie Delta, from the Beaufort Sea coast and from repeat sampling of several transects extending from inshore waters to the shelf break. This report describes the analytical results for fractionated samples with concentrations reported for alkanes, alkenes, hopanes and other triterpenes, polycyclic aromatic hydrocarbons, alcohols and sterols. (DBO)
AN: 2936310
789 of 1521
TI: Flow and particulate nutrient removal by wetland with emergent macrophyte.
AU: Hosokawa,-Y.; Horie,-T.
AF: Port and Harbour Res. Inst., Minist. Transp., 1-1, 3-chome, Nagase, Yokosuka 239, Japan
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 1271-1282
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: B (Brackish)
AB: Coastal wetland with emergent reed has the important function of settling particles in the flow. We undertook some experiments in order to ascertain the hydraulic characteristics of shallow surface flow in reed fields. The decline of water surface and the flow resistance coefficient were measured for low velocity in an experimental channel. Particle tracers were injected into the flow and the particle removal rate was calculated from the change of the particle concentration along the flow. The one-dimensional model with water level correction fits well to the data. The wetland system with reed will be a powerful means of eliminating particulate nutrient load in coastal areas.
AN: 2936226
790 of 1521
TI: Mechanisms of phosphorus released from the sediment-water interface in Xiamen Bay, Fujian, China.
AU: Wu,-Yuduan; Lin,-Yueling; Guo,-Tingzhong; Wang,-Longfa; Zheng,-Zhihong
AF: Inst. Environ. Sci., Xiamen Univ., Letter Box 99, Xiamen 361 005, Fujian, People's Rep. China
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 1087-1098
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: B (Brackish)
AB: The concentrations of DRP (dissolved reactive phosphorus) in the estuary harbour waters along the coast of China are generally low, and the N/P ratios are much higher than the Redfield ratio. From Dalian Bay to the Zhujiang Estuary these ratios are as high as n/10-n/100. Field observations at the Jiulong Estuary and Xiamen Harbour in Fujian in recent years revealed that the high values of N/P ratios are 50-80 during April-October and 90-200 during November-March, respectively. A red tide of Skeletonema costatum developed in Dalian Bay waters in the summer of 1988, where the N/P ratio was increased rapidly from 50 to 190, and reached as high a value as 340 at the end of the rampant algal propagation. This clearly indicates that phosphorus plays an important role in controlling eutrophication and red tide in China's marine coastal waters.
AN: 2935120
791 of 1521
TI: Significance of benthic regeneration in nutrient balance in the Bay of Cadiz, south-west Spain (a shallow semi-closed coastal ecosystem).
AU: Gomez-Parra,-A.; Forja,-J.M.
AF: Inst. Cienc. Mar. Andalucia (CSIC), Apdo. Ofic., 11510 Puerto Real (Cadiz), Spain
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 1079-1086
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: B (Brackish)
AB: In this study, the first in situ measurements of nutrient benthic fluxes in the Cadiz Bay (south-west Spain) are presented. This zone, which receives a large input of organic matter from urban effluents, shows a progressive increase of both primary production and organic matter contents of sediments. A preliminary balance between benthic regeneration, phytoplankton consumption and nutrient tidal export suggests the importance of other nutrient sources in the zone, such as urban and industrial effluents, nitrogen fixation and rainfall.
AN: 2935104
792 of 1521
TI: The turnover of organic matter in hypertrophic sediments below a floating fish farm in the oligotrophic Gulf of Eilat (Aqaba).
AU: Angel,-D.; Krost,-P.; Zuber,-D.; Mozes,-N.; Neori,-A.
AF: Natl. Cent. Maricult., P.O. Box 1212, Eilat 88112, Israel
CO: Japanese-Israeli Symp. on Aquaculture, Haifa/Eilat (Israel), 2-8 Nov 1992
SO: ISR.-J.-AQUACULT.-BAMIDGEH. 1992. vol. 44, no. 4, pp. 143-144
NT: Abstract only.
LA: English
ER: M (Marine)
AB: The geochemistry and ecology of sediments below a floating fish farm, located near the North Beach of Eilat (Gulf of Aqaba), have been monitored during the past 2 years. The natural (undisturbed) sediment in this region is a fine alluvial sand that supports the seagrass Halophila and endemic benthic fauna. Below the cage farm, the sediment is very fine-grained, organically enriched, and devoid of seagrasses and most of the endemic fauna. We have compiled a carbon budget for the cage farm and the region around it using measurements conducted at sea and data supplied by the fish farmers. The flux of particulate carbon deposited by the farm is approximately 7 g C/m super(2)/d, based on a daily food input of 1000 kg to the farm. The organic matter (OM) in the sediment is decomposed by both oxic and anoxic processes that account for removal of about 4.5 g C/m super(2)/d. Benthic degradation of OM (determined by H sub(2)S release rate, using flux chambers) was quite similar in both light and dark flux chambers in winter and spring. However, during summer and autumn, H sub(2)S production was very high in the dark flux chamber while there was no H sub(2)S production in the light flux chamber. We feel that these seasonal differences were due to the presence and activity of different benthic microbes. The rain of organic matter descending from the fish farm to the benthos was fairly constant throughout the study period. We found no net accumulation of organic matter in the sediment from October 1990 to May 1992, suggesting a balance between sedimentation and breakdown and/or removal of organic matter. Because sedimentation and decomposition rates showed that only 65% of the input carbon is removed by decomposition we propose that the remaining 35% is removed and/or degraded by a combination of strong bottom currents and as a result of feeding activity of native demersal fish. Furthermore, we suggest that the microbial mats play a number of important roles, including: a) mediating the mineralization of organic matter, b) controlling the flux of nutrients and gases (e.g. H sub(2)S and methane) out of the sediments, c) increasing the "surface tension" of the sediment surface and reducing the erosivity of the sediment.
AN: 2934846
793 of 1521
TI: Interactions between hydrodynamics and pelagic ecosystems: Relevance to resource exploitation and climate change.
AU: Legendre,-L.; Lefevre,-J.
AF: GIROQ, Dep. Biol., Univ. Laval, Quebec, PQ G1K 7P4, Canada
CO: Benguela Trophic Functioning Symp., (Cape Town) (South Africa), Sep 1991
SO: BENGUELA-TROPHIC-FUNCTIONING. Payne,-A.I.L.;Brink,-K.H.;Mann,-K.H.;Hilborn,-R.-eds. 1992. vol. 12 pp. 477-486
ST: S.-AFR.-J.-MAR.-SCI.-S.-AFR.-TYDSKR.-SEEWET. vol. 12
LA: English
ER: M (Marine)
AB: A proposal is made to classify the pools of biogenic carbon in the oceans by reference to their turnover times. Break points in the continuum of turnover times, located at 10 super(-2) and 10 super(2) years, distinguish between short-lived organic carbon, long-lived organic carbon and sequestered biogenic carbon. The three pools of biogenic carbon are discussed by reference to the more usual oceanographic concepts of new v. regenerated production, and export v. recycled production. Short-lived organic carbon is mainly associated with the microbial food-loop, long-lived organic carbon is relevant to renewable marine resources, and sequestered carbon is pertinent to global climate change (greenhouse effect). Recycling, export and sequestration are controlled by the proportions of primary production effects by small (< 5 mu m) and large (> 5 mu m) phytoplankton respectively, and by the selective grazing pressure experienced by cells in the various size-classes. These ecosystem processes are in turn governed by hydrodynamics. At low levels of auxiliary (mechanical) energy, the physical environment is stable, so that pelagic ecosystems are dominated by the microbial food-loop and biogenic carbon is mainly short-lived. Transitions from high levels of auxiliary energy to more stable conditions favour the production of large phytoplankton. When this takes place along predictable regular modes, primary production may be channelled into the long-lived pool, whereas stochastic transitions may lead to carbon sequestration. This theoretical framework may help the modern approaches of fisheries oceanography and biogeochemical oceanography to converge.
AN: 2934604
794 of 1521
TI: Bacterial sulfate reduction above 100 degree C in deep-sea hydrothermal vent sediments.
AU: Joergensen,-B.B.; Isaksen,-M.F.; Jannasch,-H.W.
AF: Max Planck Inst. Mar. Microbiol., Fahrenheistr. 1, 2800 Bremen 33, FRG
SO: SCIENCE-WASH.. 1992. vol. 258, no. 5089, pp. 1756-1757
LA: English
ER: M (Marine)
AB: The currently known upper temperature limit for growth of organisms, shared by a number of archaebacteria, is 110 degree C. However, among the sulfate-reducing bacteria, growth temperatures of greater than 100 degree C have not been found. A search for high-temperature activity of sulfate-reducing bacteria was done in hot deep-sea sediments at the hydrothermal vents of the Guaymas Basin tectonic spreading center in the Gulf of California. Radiotracer studies revealed that sulfate reduction can occur at temperatures up to 110 degree C, with an optimum rate at 103 degree to 106 degree C. This observation expands the upper temperature limit of this process in deep-ocean sediments by 20 degree C and indicates the existence of an unknown group of hyperthermophilic bacteria with a potential importance for the biogeochemistry of sulfur above 100 degree C.
AN: 2934510
795 of 1521
TI: Environmental systems, an introductory text. Second edition.
AU: White,-I.D.; Mottershead,-D.N.; Harrison,-S.J.
SO: NEW-YORK,-NY-USA CHAPMAN-AND-HALL 1992. 616 pp
NT: Price: $39.95 (USA); $49.55 (Canada), paperback.
LA: English
AB: This introductory text is an integrated and unified account of systems on all scales from planetary to molecular. Using energy flow and mass transfer as unifying themes, the discussion is set in a thermodynamic perspective. The concepts and terminology of the systems approach are dealt with in full. The approach is based on a nested hierarchy of systems in which human-environment interactions and the functional connections within them and between them are dealt with. For the second edition, all chapters have been revised. In part B, there is a new chapter on the hydrosphere dealing with the effect of the oceans of the energetics and biochemistry of the planet. The biosphere and ecosphere chapters have been condensed into one, with more emphasis on the nature of human interference in biogeochemical cycles. There are new chapters on eolian systems and on coastal systems. There is also new material on landscape ecology and climatic change, including the effect of ozone holes.
AN: 2933929
796 of 1521
TI: The role of sesarmid crabs in the mineralization of leaf litter of Rhizophora apiculata in a mangrove, southern Thailand.
AU: Poovachiranon,-S.; Tantichodok,-P.
AF: Phuket Mar. Biol. Cent., P.O. Box 60, Phuket 83000, Thailand
SO: RES.-BULL.-PHUKET-MAR.-BIOL.-CENT. 1991. no. 56, pp. 63-74
LA: English
ER: M (Marine)
AB: Data of leaf fall within 28 weeks are reported from a mangrove forest at Ao Nambor, Phuket, Thailand. The analysis of foregut contents of 5 species of sesarmid crabs (Neoepisesarma and Chiromanthes spp.) indicates that they are primarily herbivores. Consumption rate experiments and preference rate experiments in aquaria showed that brown and green leaves were preferred food sources for sesarmid crabs. Leaf removal by sesarmid crabs in mangrove forest indicated very large variations in feeding activity. Chemical composition of green, yellow and brown leaves of Rhizophora apiculata were analysed.
AN: 2933203
797 of 1521
TI: Photochemical studies of the Eastern Caribbean: An introductory overview.
AU: Zika,-R.G.; Milne,-P.J.; Zafiriou,-O.C.
AF: Rosenstiel Sch. Mar. Atmos. Sci., Univ. Miami, Miami, FL, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1993. vol. 98, no. C2, pp. 2223-2232
NT: Photochemistry of Eastern Caribbean waters.
LA: English
ER: M (Marine); B (Brackish)
AB: This special section of the Journal of Geophysical Research reports a multi-investigator study of a number of sunlight-initiated photoprocesses taking place in the varied biogeochemical and oceanographic environment found in the tropical Eastern Caribbean and Orinoco River delta in the spring and fall of 1988. Principal conceptual themes that were addressed by the program included (1) the characterization of the role of dissolved organic matter as the main chromophore initiating photoprocesses in surface seawater, (2) the determination of the fluxes and pathways of reactants and transient species involved in oxygen photoredox chemistry, and (3) the continuing development of chemical mapping strategies, including observing and modelling reactive phototransient distribution in terms of their sources, mixing, and fates. Ancillary supporting studies included observation of water mass tracers, dissolved trace gases, atmospheric components, nutrients and the geochemistry of estuarine mixing processes in an important continental margin. The observational and mechanistic investigations reported here feature a number of novel or improved methods allied with some advanced underway sampling, sensing and computing facilities that were implemented aboard the R/V Columbus Iselin . Results from the study showed large-scale (-1000 km) seasonal variations in surface water photoreactivity, optical and biooptical characteristics over much of the Caribbean Basin. These changes resulted from seasonally varying riverine inputs of organic chromophores, nutrients and suspended material. Smaller scale (10-100 km) studies carried out in the Orinoco delta and the Gulf of Paria showed that estuarine mixing processes did not affect major net removal of dissolved organic matter, consistent with the hypothesis that riverine chromophore input plays a dominant role in open-water photochemistry.
AN: 2932983
798 of 1521
TI: Nitrogen and phosphorus compounds in bottom sediments: Mechanisms of accumulation, transformation and release.
AU: Martinova,-M.V.
AF: Inst. Water Problems, Sadovo-Chernogriazskaja 13/3, 103064 Moscow, Russia
SO: HYDROBIOLOGIA. 1993. vol. 252, no. 1, pp. 1-22
NT: Spec. Iss.: Sediment-Water Interaction 4.
LA: English
ER: F (Freshwater)
AB: This paper is an overview of Russian literature dealing with the accumulation, the transformations and the release of phosphate and nitrogen compounds in a great number of Russian lakes and reservoirs. A considerable data bank has been analysed. Special attention is given to the relation of N- and P- accumulation with the input and transformation of organic carbon, as well as to the release mechanisms, often in relation to eutrophication of the lakes and reservoirs. It is shown that the major input of organic matter into the sediments comes from autochthonous material, and is usually > 70%. The relative importance of phytoplankton and macrophytes as sources of organic matter is discussed; it appears that trophic state, depth and other factors may have a large influence on this ratio. In shallow eutrophic lakes macrophytes may be the source of organic matter, which source can amount to 1.5-2.5 times that of phytoplankton. It is also shown that the C/N ratio is not a good indicator of the source of the organic matter, because their C/N ratios often are not very different. The decomposition rate of organic matter was analysed; it depends on trophic state and other factors.
AN: 2932721
799 of 1521
TI: Manganese dynamics in surface waters of the eastern Caribbean.
AU: Waite,-T.D.; Szymczak,-R.
AF: Australian Nuclear Sci. Technol. Org., Menai, N.S.W., Australia
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1993. vol. 98, no. C2, pp. 2361-2369
NT: Photochemistry of Eastern Caribbean waters.
LA: English
ER: M (Marine)
AB: The rate of photoreductive dissolution of manganese oxide in eastern Caribbean waters appears to be relatively rapid with an approximate linear dependency of dissolution rate on organic content of these waters. From the magnitude of derived absolute dissolution rates it would appear that reductive rather than oxidative processes should dominate transformations of manganese in surface waters though further insight into the reactivity of "naturally occurring" oxides is needed. Oxidation of Mn(II) added to surface water samples is observed and occurs at rates between those observed for coastal and open ocean surface waters by other investigators. Obvious correlations between oxidation rates and water column characteristics such as total bacterial numbers, dissolved (or particulate) manganese concentrations or organic content of surface waters are not evident. Transformations of manganese in the surface waters of the eastern Caribbean appear to be masked by the supply of fresh particulate material presumably, in part at least, from the Orinoco River.
AN: 2932681
800 of 1521
TI: The impact of desiccation of a freshwater marsh (Garcines Nord, Camargue, France) on sediment-water-vegetation interactions. Part 1: The sediment chemistry.
AU: Groot,-C.-J.-de; Wijck,-C.-van
AF: Assoc. "Leiden-Camargue", c/o Stn. Biol. Tour du Valat, Le Sambuc, 13200 Arles, France
SO: HYDROBIOLOGIA. 1993. vol. 252, no. 1, pp. 83-94
NT: Spec. Iss.: Sediment-Water Interaction 4.
LA: English
ER: F (Freshwater)
AB: The impact of desiccation on a marsh sediment was studied both in the laboratory and in the field. Changes in the sediment chemistry of a homogenized sediment suspension during desiccation were studied in the laboratory. FeS was oxidized completely. A considerable mineralization of organic phosphate took place, from both the acid soluble organic phosphate fraction and from the residual organic phosphate fraction, but no significant mineralization of organic matter was observed. The o-P formed during the mineralization was recovered partly in the Fe(OOH) approximately equals P fraction and partly in the CaCO sub(3) approximately equals P fraction. An upward flux was found. During spring and summer 1990 the water inlet to a shallow permanent freshwater marsh with an surface of about 1.5 hectares was blocked, in order to desiccate the marsh by evaporation. The sediments initially consisted of a black anoxic organic top layer and a less organic anoxic gray layer. During the desiccation of the sediment a brown oxic surface layer was formed from the black layer and an increase of pH and Eh occurred. Subsequent rainfall made the Eh increase further but caused a decrease in pH indicating an increase in bacterial activity. Drying may be utilized as a tool, in wetland management, to eliminate organic nitrogen and carbon from the sediment. In rice culture, it may be used to make part of the organic nitrogen available to the rice.
AN: 2932589
801 of 1521
TI: The role of Gloeotrichia echinulata in the transfer of phosphorus from sediments to water in Lake Erken.
AU: Pettersson,-K.; Herlitz,-E.; Istvanovics,-V.
AF: Uppsala Univ., Inst. Limnol., Erken Lab., Norr Malma 4200, S-761 73 Norrtaelje, Sweden
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 123-129
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: The abundance of Gloeotrichia echinulata colonies in the sediments of Lake Erken and their phosphorus content were investigated to determine the contribution of Gloeotrichia colonies to total sediment phosphorus. Moreover, the potential size of the algal inoculum and the migration to the water during summer were estimated. The surplus phosphorus content of the resting colonies in the sediment was about 45% of total phosphorus, which maximized at 8.5 mu g P/(mg dw) or 81 mu g P/colony. The C:P ratio (by weight) in the early colonies appearing in the lake water was 50:1, while the ratio stabilized at 150 during the major migration period. The internal supply of surplus phosphorus was used during the pelagic growth of the colonies. The internal phosphorus loading to the epilimnion of Lake Erken due to Gloeotrichia migration could, from the measurements of the increase in particulate epilimnetic phosphorus, be estimated at 40 mg P/m super(2) or 2.5 mg P/m super(2)/d in late July and early August. Determination of the number of colonies in the sediment before and during the migration verified this value to be a conservative estimate of the internal phosphorus loading due to Gloeotrichia) migration to the epilimnion in Lake Erken. The sediment P content calculated from the P concentration in early epilimnion colonies resulted in a value of 35 mu g P/(g dw) as a maximum. This corresponds to only 3% of the total phosphorus content in Lake Erken sediment.
AN: 2932310
802 of 1521
TI: The role of microorganisms in mobilization and fixation of phosphorus in sediments.
AU: Gaechter,-R.; Meyer,-J.S.
AF: Inst. Aquat. Sci. (EAWAG), Swiss Fed. Inst. Technol (ETH), CH-6047 Kastanienbaum, Switzerland
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 103-121
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: Cycling of phosphorus (P) at the sediment/water interface is generally considered to be an abiotic process. Sediment bacteria are assumed to play only an indirect role by accelerating the transfer of electron from electron donors to electron acceptors, thus providing the necessary conditions for redox- and pH-dependent, abiotic sorption/desorption or precipitation/dissolution reactions. Results summarized in this review suggest that in eutrophic lakes, sediment bacteria contain as much P as settles with organic detritus during one year, in oligotrophic lakes, P incorporated in benthic bacterial biomass may exceed the yearly deposition of bioavailable P several times, storage and release of P by sediment bacteria are redox-dependent processes, an appreciable amount of P buried in the sediment is associated with the organic fraction, sediment bacteria not only regenerate PO sub(4), they also contribute to the production of refractory, organic P compounds, and in oligotrophic lakes, a larger fraction of the P settled with organic detritus is converted to refractory organic compounds by benthic microorganisms than in eutrophic lakes. From this we conclude that benthic bacteria do more than just mineralize organic P compounds. Especially in oligotrophic lakes, they also may regulate the flux of P across the sediment/water interface and contribute to its terminal burial by the production of refractory organic P compounds.
AN: 2932261
803 of 1521
TI: P-flux regulation in sediments by transport processes.
AU: Ripl,-W.
AF: TU-Berlin, Inst. Oekol., Fachgebiet Limnol., FRG
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 p. 218
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Lake internal phosphorus-recycling from sediments is a significant process in most eutrophic shallow lakes. The mechanisms for P-liberation in the sediments are coupled microbial processes depending on water transport at the sediment-water interface. Thereby electron acceptors are supplied to sessile microassemblages of bacteria and inhibitory products, such as hydrogen sulphide, are removed by water transport. This relations where shown by time series in interstitial water strata and lake-budget calculations for several lakes in the Berlin-region, the Schlei-estuary and Swedish lakes. In shallow eutrophic lakes up to 1 g/m super(2)/month phosphorus have been liberated by the process of internal fertilisation from sediments during short periods in summer and autumn. This was equal to the whole phosphorus content of the upper 2 mm of surface sediments and resulted in a large increase of phosphate concentration in water column. The periods of internal P-liberation where coupled with high rates of plankton sedimentation and depleted oxidized nitrogen by denitrification in sediment surface. In these periods desulfurication became the main respiration-process in sediment metabolism. The sediment studies showed a monocausal hierarchy of processes. The energyflow partly resulting in water transport and in chemical reactions control the sediment metabolism with respect to space and time distribution of microbial activity.
AN: 2932200
804 of 1521
TI: The role of microbial processes in the phosphorus flux regulation between sediments and water.
AU: Sinke,-A.J.C.; Cottaar,-F.H.M.; Buis,-K.; Keizer,-P.
AF: Limnol. Inst., Rijsstraatweg 6, 3631 AC Nieuwersluis, Netherlands
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 p. 218
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: B (Brackish)
AB: In aquatic sediments the mineralization of organic matter regenerates phosphates, resulting in an accumulation of phosphates in the interstitial water and the formation of a concentration gradient. The subsequent diffusive transport to the overlying water is affected by chemical and microbial processes. Especially the redox state of the sediment is known to be an important factor determining the actual phosphate flux. The presence of an oxidized microlayer at the sediment surface is considered to be an important trap for phosphates. The high adsorption capacity of the oxidized microzone is generally ascribed to the presence of iron(III)-hydroxides. Lately, also the role of microorganisms has come into focus. Microorganisms in the surface layer of the sediment might act as a redox dependent source/sink mechanism of phosphates. This contribution is focused on the role of methane oxidizing bacteria in the sediment surface. In Lake Loosdrecht almost the entire methane flux diffusing upward is oxidized in the sediment surface layer. In periods with high methane production the major fraction of the oxygen consumption of the sediment can be ascribed to methanotrophic bacteria. An experimental setup will be described which enabled us to manipulate the methane flux toward the sediment surface. Microelectrode equipment was used to quantify the oxygen consumption and tThe oxygen penetration depth. In columns with high activity of methanotrophic bacteria a decrease in the oxygen penetration depth could be demonstrated. However, these columns appeared to have a higher phosphate adsorption capacity than the controls. Batch experiments were conducted to examine the role of methanotrophic bacteria in the uptake of phosphates.
AN: 2932066
805 of 1521
TI: Phosphate compounds in sediments. 2. Organic aspects.
AU: Groot,-C.J.-de; Golterman,-H.L.
AF: Stn. Biol., Tour du Valat, Arles 13200, France
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 p. 100
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Although org-P accounts for a large part of the P sub(sed), little is known about its chemical and biological properties. In most studies investigating the chemical nature of org-P sub(sed) compounds, only a small percentage could be characterized. Of the compounds found phytic acid and related compounds were quantitatively the most important. In this study three different approaches have been combined, to study the properties of org-P sub(sed): (1) The complex and adsorption chemistry of phytic acid and its bioavailability were studied in laboratory experiments. (2) Algae were killed and left to mineralize in an "artificial" sediment. The properties of the remaining organic phosphate compounds were investigated. (3) After removal of Fe(OOH) approximately equals P and CaCO sub(3) approximately equals P, the remaining org-P was studied on Camargue sediments. An attempt was made to characterize the nature of ASOP (Acid Soluble Org-P). Phytic acid was found to form complexes with Ca super(2+), Mg super(2+), Mn super(2+), Fe super(2+) and Fe super(3+). The Fe complexes were found to be the most stable in the presence of chelating agents. All complexes dissolved in diluted acid.
AN: 2932060
806 of 1521
TI: Considerations in modeling the sediment-water exchange of phosphorus.
AU: Lijklema,-L.
AF: Nat. Conserv. Dep., Agric. Univ., P.O. Box 8080, 6700 DD Wageningen, Netherlands
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 219-231
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: The potential to release accumulated phosphorus from sediments has been the major motive to study and to model the fate of this nutrient in sediments. For the dynamics of the sediment-water interaction the sizes of the pools involved and the rates of conversion/transport from one pool to another are of primary interest. As the sediment pools for phosphate are generally much larger than the pools in the water column, a rather slow adjustment of the sediment to management measures will occur. For the analysis of management measures it is obvious that the gradual change in sediment composition must be taken into account. Only for rather short periods the sediment composition can be assumed to be constant; this may be appropriate for studies of e.g. the annual cycle. The sediment-water interaction is a complex resultant of physical, chemical and biological processes. Aspects which are discussed and need to be considered in application of a model in research or management are the level of aggregation and detail that is required and may still be practical, the spatial and temporal scales which are applicable for the processes mentioned and their influence upon the numerical dispersion and model stability, the availability of data for calibration/validation and the resolution of the analytical techniques. These aspects are not independent however. Frequently models are not functional because they contain details which are either unnecessary or suggest a feigned accuracy which is not justified by analytical and experimental resolution of system characteristics.
AN: 2932058
807 of 1521
TI: Phosphate compounds in sediments. 1. Inorganic and biological aspects.
AU: Golterman,-H.L.; Graaf,-I.M.-de; Groot,-C.J.-de
AF: Stn. Biol., Tour du Valat, Arles 13200, France
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;van-Raaphorst,-W.-eds. 1993. vol. 253, no. 1-3 pp. 99-100
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: The chemical adsorption of phosphate onto sediments may be caused by Fe(OOH) and/or CaCO sub(3). Mathematically the adsorption can be described by a Langmuir or a Freundlich isotherm. Analyzing several chemical reaction mechanisms for the equilibrium between (o-P) sub(w) and P sub(sed) leads, under certain conditions, to the Freundlich isotherm, and the best description that can be proposed at the moment is P sub(sed) = A super(*)(o-P) sub(w) super(0.33) with A being a negative, nearly linear function of the pH. The constant "A" does not depend only on the pH; compounds like NaCl, MgCl sub(2) and CaCl sub(2) etc. influence "A" strongly. We think that ion activities cause this effect through the electric double layer of the Fe(OOH). A different effect is caused by the presence of S super(2-), which renders the Fe(OOH) inactive. This inactivation can be undone by denitrification. The adsorption onto CaCO sub(3) can be explained by the soluble Ca super(2+) concentration, which causes the product formed (probably apatite) to be co-precipitated with CaCO sub(3). A range of values for the solubility product of apatite is proposed. Data from the rivers Rhine and Rhone suggest a value near 10 super(-50). The Ca and Fe phosphate adsorption mechanisms can be combined to a solubility diagram, of which a new numerical version will be presented. Sediments from about 10 lakes have been analyzed for FeOOH approximately equals P and CaCO sub(3) approximately equals P using sequential extractions with Ca-NTA and Na-EDTA. Furthermore the bioavailability of the P sub(sed) for the alga Scenedesmus sp. was measured in bioassays. Bioavailability was compared with the different fractions. It appeared that especially the sum of the FeOOH approximately equals P and CaCO sub(3) approximately equals P fractions was available, while "org-P" was not available.
AN: 2932031
808 of 1521
TI: Phosphorus composition and release in sediment bacteria of the genus Pseudomonas during aerobic and anaerobic conditions.
AU: Waara,-T.; Jansson,-M.; Pettersson,-K.
AF: Inst. Limnol., Univ. Uppsala, Box 557, S-75122 Uppsala, Sweden
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 131-140
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: A substantial amount of sediment phosphorus can be bound in bacterial biomass. In this study the fractional composition of phosphorus in the bacteria Pseudomonas was determined by sequential extraction with ammonium chloride, sodium hydroxide and hydrochloric acid according to the scheme of Hieltjes & Lijklema (1980). Both non-labelled and super(32)P-labelled bacteria were used for fractionation. Up to 80% of the bacteria phosphorus was found in the NaOH-nRP fraction, which is in agreement with the results of Hupfer & Uhlman (1992) for Acinetobacter and activated sludge obtained with the sequential extraction scheme of Psenner et al. (1985). A significant correlation was found between bacterial biomass and the amount of phosphorus retained in the NaOH-nRP fraction when sediments were fractionated. Additional experiments with super(32)P-labelled Pseudomonas in sediment-water systems were performed in order to follow bacterial release of phosphorus under aerobic and anaerobic conditions. These studies did not sustain the hypothesis that anaerobic conditions lead to rapid release of phosphorus from bacterial cells.
AN: 2931981
809 of 1521
TI: The effect of deposition of organic matter on phosphorus dynamics in experimental marine sediment systems.
AU: Slomp,-C.P.; Van-Raaphorst,-W.; Malschaert,-J.F.P.; Kok,-A.; Sandee,-A.J.J.
AF: Netherlands Inst. Sea Res., P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Van-Raaphorst,-W.-eds. 1993. vol. 253, no. 1-3 pp. 83-98
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: M (Marine)
AB: The effect of deposition of organic matter on phosphorus dynamics in sandy marine sediments was evaluated using an experimental system (boxcosms) and three different strategies: (1) no supply (2) one single addition (3) weekly additions of a suspension of algal cells (Phaeocystis sp.). Macrofauna (3 species, 6 individual of each) were added to half of the boxes. Both in the case of the single and weekly additions a clear effect of increased organic matter loading on phosphorus dynamics was found. Following the organic matter addition, porewater phosphate concentrations in the upper sediment layer increased, phosphate release rates from the sediment increased by a factor 3-5 and in the boxes to which a single addition was applied NaOH-extractable phosphorus increased substantially. The increase in phosphate release rates from the sediment was attributed to mineralization of the added material and to direct release from the algal cells. No clear effect of the presence of macrofauna on sediment-water exchange of phosphate could be discovered. The macrofauna were very effective at reworking the sediment, however, as illustrated by the organic carbon profiles. It is hypothesized that the sediment-water exchange rates of phosphate were regulated by the layer of algal material which was present on the sediment surface in the fed boxes. In the boxes to which the single addition was applied porewater phosphate concentrations were lower and NaOH-extractable phosphorus was higher in the presence of macrofauna, suggesting that macrofauna can stimulate phosphate binding in the sediment.
AN: 2931979
810 of 1521
TI: The relative importance of biological and chemical processes in the release of phosphorus from a highly organic sediment.
AU: Montigny,-C.-de; Prairie,-Y.T.
AF: Dep. Sci. Biol., Univ. Quebec, C.P. 8888 Succ. A, Montreal, PQ H3C 3P8, Canada
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 141-150
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: Bacteria can play an important role in the process of anaerobic phosphorus release: they can act as a direct source of orthophosphates, or as a catalyst of iron hydroxide reduction. We studied their influence on phosphorus release from highly organic sediments of a Canadian shield lake. Phosphorus and iron release were measured under aerobic and anaerobic conditions, with or without sterilization, and at different pH. We measured also the abundance and activity of bacteria in sediments. The increased P release after sterilization can be explained by cell lysis. Compared to sterilization, changing oxygen concentrations or acidification had little or no effect on P release. In these sediments, phosphorus and iron movements were independent. Most of the total dissolved iron seemed to be linked to humic acids, but not phosphorus.
AN: 2931963
811 of 1521
TI: Transformations between organic and inorganic sediment phosphorus in Lake Balaton.
AU: Istvanovics,-V.
AF: Balaton Limnol. Res. Inst., Hungarian Acad. Sci., H-8237 Tihany, Hungary
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 193-206
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: In order to estimate microbial P content and biological P uptake in sediments, the tungstate precipitation method of Orrett & Karl (1987) was used in sediment extracts. This method allows a simple and rapid separation of organic and inorganic super(32)P radioactivity. Either inorganic super(32)P (as carrierfree H sub(3) super(32)PO sub(4)) or organic super(32)P (as super(32)P-labelled algal material) was added to surface sediment suspensions of shallow Lake Balaton. Inorganic super(32)P was rapidly transformed into organic super(32)P, and this process was completely inhibited by formaline. P content of living benthic microorganisms was estimated from steady state distribution of the radioactivity. Transformation of algal organic P into inorganic P could also be detected. In extremely P limited Lake Balaton benthic microorganisms were shown to supplement their high P requirements by inorganic P uptake. The velocity of the inorganic into organic P transformation, i.e. the rate of microbial P uptake, was comparable to P uptake in the water column. Microbial P uptake contributed significantly to total P fixation by sediments, particularly at low ( less than or equal to 100 mu g P/l) phosphate additions.
AN: 2931942
812 of 1521
TI: Proceedings of the Third International Workshop on Phosphorus in Sediments.
AU: Boers,-P.C.M.; Cappenberg,-Th.E.; van-Raaphorst,-W.-(eds.)
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: HYDROBIOLOGIA. 1993. vol. 253, no. 1-3, 376 pp
LA: English
AB: The phosphorus cycle in aquatic environments has been a scientific topic for several decades. To quote Hutchinson "Of all the elements present in living organisms, phosphorus is likely to be the most important ecologically." Although this statement may need some differentiation, it clearly points to the basic reason for scientific interests. In limnology most studies focused on the mobilization and (bio)-availability of phosphorus. The first limnologists who recognized the importance of iron-phosphorus interactions and the coupling between mobilization and redox conditions were Einsele and Mortimer. Their observations form the basis of many studies carried out nowadays. Many of these studies concern the precise nature of iron-phosphorus bindings in sediments and suspended matter and their effect on the phosphorus buffering system, i.e. the ability of the sediments to constrain phosphate concentrations within narrow limits. The sorptive properties of soil minerals were first investigated by agronomists and soil scientists to assess "phosphate fixation" which makes part of the phosphorus applied in fertilizers unavailable to plants. In sediment-water systems phosphate fixation is studied to determine the long-term loss of phosphorus from the ecosystem to the sediments. Soil scientists also initiated the development of reliable sequential extraction schemes to distinguish between phosphorus compounds bound to different complexes and minerals.
AN: 2931787
813 of 1521
TI: P-flux regulation in sediments by coupled microbial processes.
AU: Heller,-S.
AF: Ges. Gewaesserbewirtsch., Berlin, FRG
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 p. 217
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Lake internal phosphorus-recycling from sediments is a significant process in most eutrophic shallow lakes. The mechanisms for P-liberation in the sediments are coupled microbial processes depending on water transport at the sediment-water-interface. Thereby electron acceptors are supplied to sessile microassemblages of bacteria and inhibitory products, such as hydrogen sulphid, are removed by water transport. Laboratory experiments with extractions of phosphorus by addition of hydrogen sulphid as reference (complete liberation of ironbound phosphorus) or by addition of glucose, iron and sulfate in different molar relation revealed the reaction mechanisms for various sediment types. The sediment studies showed a monocausal hierarchy of processes. The energyflow partly resulting in water transport and in chemical reactions control the sediment metabolism with respect to space and time distribution of microbial activity.
AN: 2931776
814 of 1521
TI: Sulfate control of phosphorus availability in lakes. A test and re-evaluation of Hasler and Einsele's model.
AU: Caraco,-N.F.; Cole,-J.J.; Likens,-G.E.
AF: Inst. Ecosyst. Stud., New York Bot. Garden, Millbrook, NY 12545, USA
CO: 3. Int. Workshop on Phosphorus in Sediments, Zeist (Netherlands), 30 Sep-3 Oct 1991
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-PHOSPHORUS-IN-SEDIMENTS. Boers,-P.C.M.;Cappenberg,-Th.E.;Raaphorst,-W.-van-eds. 1993. vol. 253, no. 1-3 pp. 275-280
ST: HYDROBIOLOGIA. vol. 253, no. 1-3
LA: English
ER: F (Freshwater)
AB: During summer stratification large amounts of phosphorus (P) accumulate in anoxic bottom waters of many lakes due to release of P from underlying sediments. The availability to phytoplankton of this P is inversely related to the Fe:P ratio in bottom waters. Using data from 51 lakes, we tested the hypothesis that sulfate concentration in lake water may be critical in controlling the Fe:P ratio in anoxic bottom waters. Results showed that Fe:P ratios in bottom waters of lakes were significantly (p < 0.001) related to surface water sulfate concentrations. The higher Fe:P ratios in low sulfate systems is due not only to higher iron concentrations in anoxic bottom waters but also to lower P concentrations in anoxic waters. Thus, our results suggest that anthropogenically induced increases in sulfate concentrations of waters (e.g. from fossil fuel burning) may have a double effect on P cycling in lakes. Higher sulfate concentrations can both increase the magnitude of P release from sediments as well as increase the availability of P released from sediments into anoxic bottom waters.
AN: 2931735
815 of 1521
TI: (The influence of osmoregulation systems on the survival and adaptation of enteric bacteria in the marine environment.).
OT: Influence des systemes d'osmoregulation sur la survie et l'adaptation des bacteries enteriques dans l'environnement marin
AU: Gauthier,-M.J.
AF: INSERM, Unite 303 "Mer et Sante," 1 av. Jean-Lorrain, 06300 Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-ON-RESEARCH-PROJECTS-1989-1991. CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K.-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-1989-1991 UNEP-Mediterranean-Action-Plan,-Athens-Greece;WHO,-Geneva-Switzerland ATHENS-GREECE UNEP 1992. no. 63 pp. 1-15
ST: MAP-TECH.-REP.-SER. no. 63
LA: French
ER: M (Marine)
AN: 2924830
816 of 1521
TI: Biogeochemical cycles of specific pollutants (activity K). Survival of pathogens. Final reports on research projects (1989-1991).
OT: Cycles biogeochimiques de polluants specifiques (activite K). Survie des pathogenes. Rapports finaux sur les projets de recherche (1989-1991)
CA: UNEP Mediterranean Action Plan, Athens (Greece)
WHO, Geneva (Switzerland)
SO: MAP-TECH.-REP.-SER. ATHENS-GREECE UNEP 1992. no. 63, 85 pp
LA: French
ER: M (Marine)
AN: 2924820
817 of 1521
TI: Comparative study of the adsorption of organic ligands on aluminum oxide by titration calorimetry.
AU: Benoit,-P.; Hering,-J.G.; Stumm,-W.
AF: Dep. Civ. Eng., 4173 Engineering I, Univ. California, Los Angeles, CA 90024-1593, USA
SO: APPL.-GEOCHEM. 1993. vol. 8, no. 2, pp. 127-139
LA: English
ER: F (Freshwater)
AB: Ligand adsorption on delta -Al sub(2)O sub(3) at pH 8 was examined for a series of organic ligands (aromatic acids, monochlorophenols and aliphatic acids) including both monodentate and bidentate ligands. Adsorption isotherms for the aromatic acids exhibited saturation at high dissolved ligand concentrations; saturation was not observed (over the concentration range examined) for the chlorophenols. Small, though measurable, amounts of heat were evolved on reaction of the aromatic acids, the monochlorophenols and propionate (but not of the longer chain fatty acids) with the oxide surface; overall ligand adsorption reactions were exothermic ( Delta H sub(obs) < 0). For adsorption of (partially or fully) protonated ligands, the favorable Delta H sub(obs) was due largely to the exothermic proton transfer reaction between phenolic hydroxyl groups of the ligands and hydroxide ions displaced from the oxide surface. The enthalpy corresponding to the ligand-exchange reaction of surface hydroxyl groups for the various ligands (as fully deprotonated species), Delta H sub(corr), appeared to be related to the ligand structure. The surface ligand-exchange reaction was more exothermic for the dicarboxylic acid phthalate than for the monocarboxylic acids benzoate or propionate or for salicylate and was endothermic for the chlorophenols.
AN: 2923952
818 of 1521
TI: The role of macrophytes in phosphorus turnover: Sources and sinks.
AU: Waisel,-Y.; Oertli,-J.J.; Stahel,-A.
AF: Dep. Bot., Tel Aviv Univ., Tel Aviv 69978, Israel
CO: 8. Int. Symp. on Aquatic Weeds, Uppsala (Sweden), 13-17 Aug 1990
SO: 8th-INTERNATIONAL-SYMPOSIUM-ON-AQUATIC-WEEDS.-SWEDISH-UNIVERSITY-OF-AGRICULTURAL-SCIENCES,-UPPSALA,-SWEDEN,-13-17-AUGUST-1990. Barrett,-P.R.F.;Greaves,-M.P.;Murphy,-K.J.;Pieterse,-A.H.;Wade,-P.M.;Wallsten,-M.-eds. WAGENINGEN-NETHERLANDS EUROPEAN-WEED-RESEARCH-SOCIETY 1990. pp. 243-248
LA: English
ER: F (Freshwater)
AB: Aquatic plants absorb P from the sediments as well as from the overlaying water. Leaves have a higher absorption capability of P than roots. Mature leaves of Potamogeton crispus and Myriophyllum spicatum , are covered with thick mineral crusts which may comprise 80% of their dry weight. Such crusts may fix significant quantities of P. Leaf-crusts of P. crispus contain calcite, quartz, apatite and aragonite. Aragonite is not always present in the crusts of Egeria densa . Roots of macrophytes absorb P from the soluble fraction of the sediment, at much higher rates than from the adsorbed or from the fixed fractions.
AN: 2922842
819 of 1521
TI: Phosphorus and nitrogen storage/release capacity of aquatic macrophytes in two wetland/stream systems of the Taylor Creek/Nubbins Slough and Kissimee River basin, Florida.
AU: Agami,-M.; Reddy,-K.R.; Graetz,-D.A.; Scinto,-L.J.
AF: Dep. Bot., Tel Aviv Univ., Tel Aviv 69978, Israel
CO: 8. Int. Symp. on Aquatic Weeds, Uppsala (Sweden), 13-17 Aug 1990
SO: 8th-INTERNATIONAL-SYMPOSIUM-ON-AQUATIC-WEEDS.-SWEDISH-UNIVERSITY-OF-AGRICULTURAL-SCIENCES,-UPPSALA,-SWEDEN,-13-17-AUGUST-1990. Barrett,-P.R.F.;Greaves,-M.P.;Murphy,-K.J.;Pieterse,-A.H.;Wade,-P.M.;Walsten,-M.-eds. WAGENINGEN-NETHERLANDS EUROPEAN-WEED-RESEARCH-SOCIETY 1990. pp. 1-2
LA: English
ER: F (Freshwater)
AB: The findings are presented of a field study conducted to determine the seasonality of nutrient uptake and storage, and the rate of plant tissue decomposition and subsequent nutrient release in aquatic plants in the Dry Lake 2 and Rucks Lake wetlands/stream systems in Florida, USA. Results suggest that the aquatic macrophytes present in both systems do not function as a net sink for P and N; these nutrients are stored transitionally and are eventually released back into the system.
AN: 2922086
820 of 1521
TI: Reactions depending on iron sulfide and linking geochemistry with biochemistry.
AU: Bloechl,-E.; Keller,-M.; Waechtershaeuser,-G.; Stetter,-K.O.
AF: Lehrst. Mikrobiol., Univ. Regensburg, Universitaetsstr. 31, D-8400 Regensburg, FRG
SO: PROC.-NATL.-ACAD.-SCI.-USA. 1992. vol. 89, no. 17, pp. 8117-8120
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Iron sulfide gives rise to unusual reducing reactions: some dependent on FeS/H sub(2)S synergism (NO sub(3)@)u- arrow right NH sub(3); HC identical with CH arrow right H sub(2)C = CH sub(2), H sub(3)C--CH sub(3); -CH sub(2)--CO- arrow right -CH = CH-, -CH sub(2)--CH sub(2)-; HS--CH sub(2)--COOH arrow right CH sub(3)--COOH; others dependent on FeS alone (HS--CH sub(2)--CH sub(2)--X arrow right CH sub(2) = CH sub(2) (where X = OH, SH, or NH sub(2))). The experimental conditions are geochemically plausible: 100 degree C, aqueous, nearly neutral, and fastidiously anaerobic. These reactions establish additional facts of soil chemistry, organic geochemistry, and the global nitrogen cycle, and point to the common evolutionary denominator of geochemistry and biochemistry. In their quest for phylogenetically deep-branching hyperthermophilic bacteria and archaea the authors tried to enrich organisms from sites with abundant pyrite deposits by using FeS/H sub(2)S as a hydrogen source. Surprisingly, in the presence of nitrate, large amounts of ammonia were formed abiotically within the noninoculated controls. Subsequent systematic experiments gave unequivocal evidence for a synergistic effect of H sub(2)S and FeS for the reduction of NO sub(3)@)u- to NH sub(3)-FeS alone causing only minor conversion, and H sub(2)S alone causing none. This kind of nitrate reduction may be assumed to proceed in nature. This result solves an old geochemical problem. The global nitrogen cycle can now be seen as operating partly by microbial nitrate reduction and partly by an FeS/H sub(2)S-driven abiotic nitrate reduction. The latter must have operated before the advent of nitrate-reducing microorganisms. This result is also of ecological significance. Nitrate ions and anaerobic pyrite-forming conditions cannot exist. This fact means that nitrate reduction, exhibited in the laboratory by anaerobic organisms from pyrite-forming habitats, may well be ecologically irrelevant. The result also has biochemical significance. It suggests a mechanistic commonality between the iron-sulfur clusters of nitrite reductases and nitrate reduction by FeS/H sub(2)S. The evolution of enzymatic nitrate reduction may now be traced back to abiotic nitrate reduction.
AN: 2919711
821 of 1521
TI: Nutrient release from sediments and the role of bioturbation in the Goro Lagoon (Italy).
AU: Barbanti,-A.; Ceccherelli,-V.U.; Frascari,-F.; Rosso,-G.; Reggiani,-G.
AF: Ist. Geol. Mar., CNR, Via Zamboni 65, Bologna, Italy
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 475-488
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: B (Brackish)
AB: The nutrients released from the sea bottom through resuspension or diffusion may play an important role in determining the trophic state of aquatic environments. Direct measurements of NH sub(3), PO sub(4) and SiO sub(2) fluxes were made by means of benthic chambers in the Sacca di Goro, Italy, (a lagoon within the Po River Delta), as an obvious consequence of previous investigations into the processes of nutrient regeneration and release from the sea bottom in the coastal areas facing the Po River Delta. The role that macrobenthic organisms play through bioturbation and irrigation was investigated by determining and quantifying the species in the sediments below each benthic chamber. The results showed the following: generally high fluxes with significant differences between day and night hours; the importance of macrobenthos and the structures that it builds in sediments; limited differences between the two areas examined (North-Central area and Valle di Gorino--the eastern part of the Sacca di Goro Lagoon) which, however, differ considerably in terms of sedimentology and hydrology.
AN: 2919235
822 of 1521
TI: Relationships among Typha biomass, pore water methane, and reflectance in a Delaware (U.S.A.) brackish marsh.
AU: Gross,-M.F.; Hardisky,-M.A.; Wolf,-P.L.; Klemas,-V.
AF: Dep. Biol., Georgian Court Coll., Lakewood, NJ 08701, USA
SO: J.-COAST.-RES. 1993. vol. 9, no. 2, pp. 339-355
LA: English
ER: B (Brackish)
AB: Methane is a "greenhouse effect" gas produced in wetland soils, yet factors controlling its production and emission are not well understood. Often, methane pore water concentration and atmospheric flux are positively correlated. If correlations can be found among wetland plant biomass, reflectance, and methane concentrations or flux, it may be possible to study the global methane cycle using remote sensing. Our study had two objectives: to determine if remote sensing could be used to estimate biomass of Typha angustifolia plants in a Delaware (U.S.A.) brackish marsh, and to determine if Typha plants influence dissolved pore water methane concentrations throughout a year. Canopy reflectance was correlated (r = 0.887) with live aerial biomass, which was correlated with live belowground biomass (r = 0.809). Dissolved pore water methane concentrations were generally lower in vegetated than in unvegetated areas. In vegetated areas only, concentrations were much lower in the top 10 cm of sediments than at greater depths. Since over 60% of the live root/rhizome biomass is in the top 10 cm, it is likely that an oxygenated rhizosphere and methane transport through roots kept the methane concentration low near the soil surface. Substantial growing season increases in methane at depths of 10-20 cm, where the remaining live tissue is, suggest the release of enough methanogenic substrates to cause methane production to exceed methane emission/oxidation. Overall, methane concentrations diminished in winter and increased in late spring, but lagged changes in soil temperature and in live aerial biomass by two months, and were not significantly correlated with substrate salinity. Since remote sensing can be used to estimate Typha biomass, and since live root biomass influences the sedimentary methane reservoir, it might be possible to estimate methane concentrations indirectly based on remote sensing measurements.
AN: 2918983
823 of 1521
TI: Cycling of dissolved and particulate organic matter in the open ocean.
AU: Druffel,-E.R.M.; Williams,-P.M.; Bauer,-J.E.; Ertel,-J.R.
AF: Dep. Mar. Chem. and Geochem., Woods Hole Oceanogr. Inst., Woods Hole, MA, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C10, pp. 15,639-15,6
LA: English
ER: M (Marine)
AB: Radiocarbon ( Delta super(14)C), delta super(13)C, bulk carbon and organic constituent concentration measurements are presented for dissolved and particulate carbon from the North Central Pacific Ocean (NCP) and the Sargasso Sea (SS). We operationally define three overlapping pools of dissolved organic carbon (DOC): (1) DOC that is oxidizable by UV radiation (DOC sub(uv)); (2) "extra" DOC measured by Co/CoO flow-through high-temperature catalytic oxidation (DOC sub(Ft-htc)), which also has low Delta super(14)C values like DOC sub(uv) (Bauer et al., 1992a); (3) a potential residual DOC fraction that is the difference between DOC measured by discrete-injection high-temperature catalytic oxidation (DOC sub(htc)) and DOC sub(Ft-htc), and which has unknown Delta super(14)C signature. The distribution of a large fraction of DOC appears to be controlled by circulation of deep ocean waters between major oceans. The DOC in the SS is slightly younger than would be expected if circulation was the sole process controlling DOC cycling. We propose that there is more bomb super(14)C in the deep SS DOC to account for this difference. The Delta super(14)C values of suspended, and to a lesser extent sinking particulate organic carbon (POC), decrease with depth, with the suspended POC displaying a much steeper gradient in the SS than in the NCP. These data reflect the incorporation of low-activity organic matter into the POC pool, possibly through incorporation of DOC by physical adsorption and/or biological heterotrophy.
AN: 2918964
824 of 1521
TI: A dynamic nutrient budget of subsystem interactions in a salt marsh estuary.
AU: Childers,-D.L.; McKellar,-H.N.; Dame,-R.F.; Sklar,-F.H.; Blood,-E.R.
AF: Southeast Fish. Sci. Lab., NMFS, 9700 Ave. U, Galveston, TX 77551, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1993. vol. 36, no. 2, pp. 105-131
LA: English
ER: M (Marine); B (Brackish)
AB: In tidal salt marsh estuaries, the different habitats of the ecosystem interact primarily through the tidal creek water column. These interactions include nutrient and materials exchanges with the salt marsh, oyster reefs, creek bottoms, and adjacent uplands. Nutrient budgets are often used to synthesize these kinds of subsystem exchange data, and are usually based on annual totals without accounting for nutrient variability at finer temporal resolutions. In this paper, we present a dynamic budget of carbon (C), nitrogen (N), and phosphorus (P) for the North Inlet estuary, South Carolina that synthesizes subsystem flux data in a new way. We have developed a dynamic budget that uses a tidal hydrology model to generate daily areas of inundated intertidal habitat (i.e. vegetated marsh and oyster reef) from tidal heights calculated hourly and combines them with flux data to determine a net daily input to, or removal from, the water column. Daily surpluses or deficits of each nutrient were compared with daily rates of change in observed tidally-averaged nutrient concentrations. Particular emphasis was place on evaluating budget output from the intertidal subsystems. We compared our total annual budgets to values from syntheses of two North Inlet flux studies.
AN: 2918768
825 of 1521
TI: Northern Adriatic Sea: Oceanography of the basin proper and of the western coastal zone.
AU: Franco,-P.; Michelato,-A.
AF: Ist. Biol. Mare, CNR, Riva Sette Martiri 1364/A, 30122 Venezia, Italy
CO: Symposium on Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: MARINE-COASTAL-EUTROPHICATION. Vollenweider,-R.A.;Marchetti,-R.;Viviani,-R.-eds. 1992. no. Suppl. pp. 35-62
ST: SCI.-TOTAL-ENVIRON. no. Suppl.
LA: English
ER: M (Marine)
AB: The oceanographic features of the Northern Adriatic Sea are reviewed with regard to the deeper basin proper and the shallow western coastal zone, and in relation to the interplay between the physical forcing and the distribution of chemical and biological properties in the basin. Some fundamental aspects are shown: the annual variation in the density structure of the water column, from the winter complete mixing to the strong stratification during the other seasons, and the related changes in the circulation pattern and in the dynamics of the horizontal and vertical transport processes; the role of the dynamic separation between the basin proper and the coastal zone due, with variable efficiency during the year, to the coastal frontal systems, and leading to different features in the waters separated by the fronts, in regard both to the physical and the biogeochemical processes. Some effects of the oceanographic structure of the basin on the cycling of nutrients and of the organogenic suspended matter, and on the appearance of dystrophic events are discussed.
AN: 2918765
826 of 1521
TI: Marine Coastal Eutrophication.
AU: Vollenweider,-R.A.; Marchetti,-R.; Viviani,-R.-(eds.)
CO: Marine Coastal Eutrophication, Bologna (Italy), 21-24 Mar 1990
SO: SCI.-TOTAL-ENVIRON. 1992. no. suppl., (1315 pp)
LA: English
ER: M (Marine)
AB: There were more than 500 delegates and participants from 40 countries present at the International Conference on Marine Coastal Eutrophication: The Response of Marine Transitional Systems to Human Impact; Problems and Perspectives for Restoration, Bologna, Italy, 21 to 24 March, 1990, promoted by the Department of Environment of the Regional Government of Emilia-Romagna, and co-sponsored by the Italian National Research Council, UNEP, UNESCO, and FAO. Man-made eutrophication of the marine transitional systems located between land and the open oceans, i.e., estuaries, lagoons, bays, and coastal marine areas of various geomorphological configurations, also that of enclosed inland seas, has increased rapidly worldwide over the last decades affecting the marine processes that alter the natural dynamic equilibria and the biotic composition of the respective ecosystems. Consequently, eutrophication has become a treat to the sound functioning of these systems, impairing also their rational use as a resource for recreation, tourism, fishery and aquaculture. Some 98 papers were presented at the conference.
AN: 2918723
827 of 1521
TI: Effects of aeration and mixing on nitrogen and organic matter transformations in simulated fish ponds.
AU: Avnimelech,-Y.; Mozes,-N.; Weber,-B.
AF: Fac. Agricult. Eng., Technion Israel Inst. Technol., Haifa 32000, Israel
SO: AQUACULT.-ENG. 1992. vol. 11, no. 3, pp. 157-169
LA: English
ER: F (Freshwater)
AB: Both aeration and mixing are important design parameters in intensive aquaculture systems. The present study deals with the examination of the effect of each of these variables and their combined effect on the microbial transformations of organic carbon and of nitrogen. The most efficient organic carbon metabolism was found when both aeration and mixing were provided. Intensive organic matter degradation occurred also under strict anaerobic conditions, but not in systems with limited aeration. Aeration was essential for the existence of the nitrification process, however, the process was more efficient and started earlier when mixing was provided. Moreover, a denitrification process followed in aerated, non-mixed tanks, where an anaerobic bottom layer provided the conditions required for this process. Mixing of the water in fish ponds minimises the existence of non-desirable anaerobic zones in the pond and minimises ammonium accumulation in the water.
AN: 2918567
828 of 1521
TI: Posidonia oceanica : Uptake and mobilization of mercury in the Mediterranean basin.
AU: Maserti,-B.; Ferrara,-R.; Morelli,-M.
AF: CNR, Ist. Biofis., Via S. Lorenzo 26, 56127 Pisa, Italy
CO: FAO/UNEP/IAEA Consult. Meet. on the Accumulation and Transformation of Chemical Contaminants by Biotic and Abiotic Processes in the Marine Environment, La Spezia (Italy), 24-28 Sep 1990
SO: PROCEEDINGS-OF-THE-FAO-UNEP-IAEA-CONSULTATION-ON-THE-ACCUMULATION-AND-TRANSFORMATION-OF-CHEMICAL-CONTAMINANTS-BY-BIOTIC-AND-ABIOTIC-PROCESSES-IN-THE-MARINE-ENVIRONMENT-LA-SPEZIA,-ITALY,-24-28-SEPTEMBER-1990. Gabrielides,-G.P.-ed. International-Atomic-Energy-Agency,-Vienna-Austria;UNEP-Mediterranean-Action-Plan,-Athens-Greece;Minnesota-Univ.,-St.-Paul-USA.-Sea-Grant-Program ATHENS-GREECE UNEP 1991. no. 59 pp. 243-249
ST: MAP-TECH.-REP.-SER. no. 59
LA: English
ER: M (Marine)
AB: In studying the biogeochemical cycle of mercury in the Mediterranean basin the capability of the marine phanerogam Posidonia oceanica and of its epiphytes to uptake and accumulate the metal was demonstrated. A Hg-roots/hg-sediment correlation was observed, which shows that the uptake of the metal occurs mainly through the root system, even if it is not possible to exclude that the metal can also be taken up from the water by the leaves. A Hg-epiphyte/Hg-leaf correlation was also observed probably due to a limited form of parasitism between the epiphytes and their substrate. Taking into account the high primary productivity (21 ton/ha/yr) and the large extension (50,000 sq. km) of Posidonia oceanica prairies in the Mediterranean basin, the total mercury amount (9.5 ton/yr) mobilized from the sediment to the aquatic environment was evaluated.
AN: 2918241
829 of 1521
TI: Survival of pathogenic microorganisms in seawater.
AU: Romero,-P.; Borrego,-J.J.
AF: Dep. Microbiol., Univ. Malaga, Malaga, Spain
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-FINAL-REPORT-ON-PROJECTON-SURVIVAL-OF-PATHOGENIC-ORGANISMS-IN-SEAWATER. UNEP-Mediterranean-Action-Plan,-Athens-Greece;United-Nations-Environment-Programme,-Nairobi-Kenya ATHENS-GREECE UNEP 1991. no. 55 pp. 1-85
ST: MAP-TECH.-REP.-SER. no. 55
LA: English
ER: M (Marine)
AB: Microorganisms contained in sewage are dispersed by the turbulence diffusion where they are discharged into the sea. The adaptable capacity of a microbial cell may be overcome on its contact with the hostile environment, producing physiological damage which may sublethal or so intensive that it causes the death of the cell. This physiological damage or stress exerted by the marine environment on the allochtonous bacteria can be studied by observing either the bacterial structural disorganization or their inability to carry out a determined metabolic function when grown in a selective medium. However, these stressed cells can be developed in cultural media which do not contain inhibitory substances. The importance of the study of the physiological damage to pathogenic cells is based on the non-detection of these cells in the performance of standard microbiological tests, which are based on the examination of selective cultural media. A large variety of environmental conditions of factors exist which can kill, damage or simply cause the disappearance of microorganisms for the environment. These include physical, chemical and biological processes.
AN: 2918211
830 of 1521
TI: Chemical and biochemical dynamics of the C-layer.
OT: Khimicheskaya i biokhimicheskaya dinamika S-sloya
AU: Selin,-P.Yu.; Ajzatulin,-T.A.
SO: ECOLOGY-OF-THE-BLACK-SEA-COASTAL-ZONE.. EHKOLOGIYA-PRIBREZHNOJ-ZOMY-CHERNOGO-MORYA. Sapozhnikov,-V.V.-ed. MOSKVA-RUSSIA VNIRO 1992. pp. 100-126
ST: SB.-NAUCHN.-TR.-VNIRO.
LA: Russian
ER: M (Marine)
AB: The authors demonstrate the computation procedure of the chemical and biochemical dynamics of the hydrogen sulfide-oxygen coexistence layer (the C-layer) using field observation data from the northwestern Black Sea shelf and the Gotland Deep of the Baltic Sea. Data are presented on the vertical distribution profiles of vertical exchange coefficients, HS-oxidation rates, nitrification, denitrification, oxygen consumption, sulfate reduction rates, and duration of periodically occurring hydrogen sulfide zones. The appearance-disappearance of the hydrogen sulfide zones is shown to be largely dependent on the exchange conditions.
AN: 2917513
831 of 1521
TI: Microbiological activity in the water and bottom sediments of the Black Sea.
OT: Mikrobiologicheskaya aktivnost' v vode i donnykh osadkakh Chernogo morya
AU: Mitskevich,-I.N.; Kuzhinovskij,-V.A.; Rusanov,-I.I.
SO: ECOLOGY-OF-THE-BLACK-SEA-COASTAL-ZONE.. EHKOLOGIYA-PRIBREZHNOJ-ZOMY-CHERNOGO-MORYA. Sapozhnikov,-V.V.-ed. MOSKVA-RUSSIA VNIRO 1992. pp. 174-197
ST: SB.-NAUCHN.-TR.-VNIRO.
LA: Russian
ER: M (Marine)
AB: The paper presents data on the abundance of microorganisms, numbers of saprophytic forms, rates of super(14)CO sub(2) dark fixation, heterotrophic potential and rates of sulfate reduction in the water and bottom sediments of the coastal Black Sea zone and at different depths in the central part of the sea. In many samples the dark CO sub(2) fixation values were found to be much higher than those obtained by earlier investigators. On the whole, the results suggest high rates of organic matter production and destruction processes in the Black Sea.
AN: 2917381
832 of 1521
TI: Study of the biogeochemical cycle of organophosphorus pesticides in Thermaikos Gulf, Greece.
AU: Fytianos,-K.; Samanidou,-V.
AF: Environ. Pollut. Contr. Lab., Univ. Thessaloniki, Greece
SO: FINAL-REPORTS-ON-RESEARCH-PROJECTS-DEALING-WITH-MERCURY,-TOXICITY-AND-ANALYTICAL-TECHNIQUES. RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-TRAITANT-DU-MERCURE,-DE-LA-TOXICITE-ET-DES-TECHNIQUES-ANALYTIQUES. UNEP-Mediterranean-Action-Plan,-Athens-Greece;FAO,-Rome-Italy ATHENS-GREECE UNEP 1991. no. 51 pp. 133-140
ST: MAP-TECH.-REP.-SER. no. 51
LA: English
ER: M (Marine)
AB: Malathion and parathion are the most extensively used organophosphorus pesticides. Their application for the control of pests is clearly an important source of these chemicals in the environment. The object of this project was to investigate the seasonal variations and the distribution of the organophosphorus compounds in the Thermaikos Gulf (N. Greece). For the determination of these compounds, water and sediment samples were taken every three months from four sampling stations in the gulf, for a total period of one year. From the obtained data the conclusion is that the levels of the examined organophosphorus compounds are relatively close to those found for slightly polluted areas. However, particularly high concentrations were observed at the estuaries of Axios River and at the area where untreated municipal and industrial sewage are respectively discharged.
AN: 2917320
833 of 1521
TI: Biological activity of suspended matter and regeneration of biogenic elements in the Black Sea shelf zone.
OT: Biologicheskaya aktivnost' vzvesi i regeneratsiya biogennykh ehlementov v zone shel'fa Chernogo morya
AU: Agatova,-A.I.; Torgunova,-N.I.
SO: ECOLOGY-OF-THE-BLACK-SEA-COASTAL-ZONE.. EHKOLOGIYA-PRIBREZHNOJ-ZOMY-CHERNOGO-MORYA. Sapozhnikov,-V.V.-ed. MOSKVA-RUSSIA VNIRO 1992. pp. 275-305
ST: SB.-NAUCHN.-TR.-VNIRO.
LA: Russian
ER: M (Marine)
AB: The rates of organic matter transformation and nutrient regeneration in the zones of the Caucasian-Crimean and Bulgarian shelves are estimated based on the rates of the alkaline phosphatase-catalyzed phosphorolysis reaction, glycolytic hydrocarbon decomposition and the rates of complete organic matter oxidation to CO sub(2) and H sub(2)O catalyzed by enzymes of the electron transport system. The rates of organic matter destruction and nutrient regeneration were found to vary and to depend on the biological activity of suspended matter. The highest activity is characteristic for the eutrophic coastal waters (red tide) and the depth fall waters of the Bacis Black Sea Current. In these areas the time of nutrient recycling is at a minimum. Throughout the water column over the Bulgarian shelf the processes of ecosystem self-purification are less intensive than over the Caucasian shelf as the average time of complete organic matter oxidation there is twice longer.
AN: 2917270
834 of 1521
TI: (The importance of gelatinous macroplankton in the storage and transfer of metal pollutants (cadmium, copper, lead and zinc) in the northwestern Mediterranean.).
OT: Importance du macroplancton gelatineux dans le stockage et le transfert des metaux polluants (cadmium, cuivre, plomb et zinc) en Mediterranee nord-occidentale
AU: Romeo,-M.; Gnassia-Barelli,-M.; Carre,-C.
AF: INSERM Unite 303, "Mer et Sante", La Darse, 06230 Villefranche-sur-Mer, France
SO: FINAL-REPORTS-ON-RESEARCH-PROJECTS-DEALING-WITH-BIOACCUMULATION-AND-TOXICITY-OF-CHEMICAL-POLLUTANTS. RAPPORTS-FINAUX-SUR-LES-PROJECTS-DE-RECHERCHE-TRAITANT-DE-LA-BIOACCUMULATION-ET-DE-LA-TOXICITE-DES-POLLUANTS-CHIMIQUES. UNEP-Mediterranean-Action-Plan,-Athens-Greece;FAO,-Rome-Italy ATHENS-GREECE UNEP 1991. no. 52 pp. 33-41
ST: MAP-TECH.-REP.-SER. no. 52
LA: French
ER: M (Marine)
AN: 2917059
835 of 1521
TI: Meridional fluxes of dissolved organic matter in the North Atlantic Ocean.
AU: Walsh,-J.J.; Carder,-K.L.; Mueller-Karger,-F.E.
AF: Dep. Mar. Sci., Univ. South Florida, St. Petersburg, FL 33701, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C10, pp. 15625-15637
LA: English
ER: M (Marine)
AB: Using bio-optical estimates of gelbstoff and a few platinum measurements of dissolved organic carbon (DOC sub(pt)), a budget of the meridional flux of DOC and dissolved organic nitrogen (DON) across 36 degree 25'N in the North Atlantic is constructed from previous inverse models of water and element transport. Distinct southward subsurface fluxes of dissolved organic matter (DOM) within subducted shelf water, cabelled slope water, and overturned basin water are inferred. Within two cases of a positive gradient of DOC sub(pt) between terrestrial/shelf and offshore stocks, the net equatorward exports of O sub(2) and DOC sub(pt) from the northern North Atlantic yield molar ratios of 2.1 to 9.1, compared to the expected Redfield O sub(2)/C ratio of 1.3. In the first case, 63% of the apparent oxygen utilization demands of the water column may be met by DOC, instead of only 14% in the second scenario, preserving a role for falling particles in the sea. With a DOC/DON ratio of 10, the larger net southward export of DON across 36 degree 25'N balances the postulated net northward input of 1.7 x 10 super(3) kg NO sub(3) s super(-1) of unutilized nitrate within the Gulf Stream. Without an enhanced supply of DOM from the shelves, a zero seaward gradient of DOM in the third case suggests that none of the poleward nitrate flux is returned southward as DON, but instead a net poleward flux of DON prevails as well. Our present estimates are confounded, however, by the seasonal and multiyear variability of sinking processes in the North Atlantic. Future active and passive remote sensors, field programs, and simulation models must now discriminate between particulate and dissolved components of surface color signals to verify the importance of both continental margins and DOM in global biogeochemical cycles.
AN: 2913762
836 of 1521
TI: The U.S.JGOFS Bermuda Atlantic time-series study: Towards an understanding of the temporal and spatial scales of ocean biogeochemistry.
AU: Michaels,-A.F.; Knap,-A.H.; Dacey,-J.W.H.
AF: Bermuda Biological Station for Research, Inc., 17 Biological Lane, Ferry Reach, GE01, Bermuda
CO: MTS '92: Global Ocean Partnership, Washington, DC (USA), 19-21 Oct 1992
SO: MTS-'-92:-GLOBAL-OCEAN-PARTNERSHIP.-PROCEEDINGS. Marine-Technology-Soc.,-Washington,-DC-USA WASHINGTON,-DC-USA MTS 1992. pp. 535-541
ST: PROC.-MAR.-TECHNOL.-SOC.-CONF.
LA: English
ER: M (Marine)
AB: Bermuda is the site of two long-term ocean time-series programs. At Hydrostation S, the ongoing biweekly profiles of temperature, salinity and oxygen now span 38 years. This is one of the longest open-ocean time-series datasets and provides a view of decadal scale variability in ocean processes. In 1988, the U.S.JGOFS Bermuda Atlantic Time-series Study began a wide range of measurements at a frequency of 14-18 cruises each year to understand temporal variability in ocean biogeochemistry. The adequate resolution of higher frequency temporal patterns and 3-D spatial processes will require the use of new sampling tools such as biogeochemical moorings and autonomous underwater vehicles. Plans exist to deploy both at the Bermuda site in the near future.
AN: 2913188
837 of 1521
TI: Molecular biology in studies of oceanic primary production.
AU: LaRoche,-J.; Falkowski,-P.G.; Geider,-R.
CA: Brookhaven Natl. Lab., Upton, NY (USA)
SO: 1992. 23 pp.
NT: NTIS Order No.: DE92016101/GAR.
RN: CONF-9204164-1 (CONF92041641)
LA: English
ER: M (Marine)
AB: Remote sensing and the use of moored in situ instrumentation has greatly improved our ability to measure phytoplankton chlorophyll and photosynthesis on global scales with high temporal resolution. However, the interpretation of these measurements and their significance with respect to the biogeochemical cycling of carbon relies on their relationship with physiological and biochemical processes in phytoplankton. For example, the use of satellite images of surface chlorophyll to estimate primary production is often based on the functional relationship between photosynthesis and irradiance. A variety of environmental factors such as light, temperature, nutrient availability affect the photosynthesis/irradiance (P vs I) relationship in phytoplankton. The authors present three examples showing how molecular biology can be used to provide basic insight into the factors controlling primary productivity at three different levels of complexity: 1. Studies of light intensity regulation in unicellular alga show how molecular biology can help understand the processing of environmental cues leading to the regulation of photosynthetic gene expression. 2. Probing of the photosynthetic apparatus using molecular techniques can be used to test existing mechanistic models derived from the interpretation of physiological and biophysical measurements. 3. Exploratory work on the expression of specific proteins during nutrient-limited growth of phytoplankton may lead to the identification and production of molecular probes for field studies.
AN: 2912700
838 of 1521
TI: Development of a dynamic model for the assessment of environmental radiation exposures through the stagnant water pathway.
OT: Erstellung eines dynamischen Modells zur Berechnung der Strahlenexposition ueber den Wasserpfad bei stehenden Gewaessern
AU: Saenger,-W.; Huebel,-K.
CA: Bundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (FRG)
SO: 1991. 48 pp
NT: NTIS Order No.: TIB/B92-02411/GAR.
RN: BMU-1991-320 (BMU1991320)
LA: German
ER: F (Freshwater)
AB: The model describes time-dependent changes in activity concentrations that 5 ecological variables (water, tripton, plankton, sediment, fishes) undergo in stagnant waters after brief exposure to high radioactive loads. The evaluation of Chernobyl data within the context of this model leads to meaningful results, if one describes the radionuclide migration as being faster than all subsequent activity changes - preferably as the so-called delta function. The model comprises a system of 5 coupled, analytically approachable rate balances in the form of 5 time-dependent first degree differential equations with constant coefficients. The latter are determined by adjusting the analytical solutions for the model system (model functions) to the values measured.
AN: 2912651
839 of 1521
TI: Potential role of sponge spicules in influencing the silicon biogeochemistry of Florida lakes.
AU: Conley,-D.J.; Schelske,-C.L.
AF: Horn Point Environ. Lab., Cent. Environ. and Estuar. Stud., Univ. Maryland, Box 775, Cambridge, MD 21613, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1993. vol. 50, no. 2, pp. 296-302
NT: Incl. bibliogr.: 38 ref.
LA: English
ER: F (Freshwater)
AB: Amorphous silica, e.g. biogenic silica (BSi), contained in diatoms and in sponge spicules was estimated by time course extraction from surficial sediment samples of 82 Florida, USA, lakes. Separation of diatom BSi from sponge BSi was based on the observation that diatoms completely dissolve within 2 h of digestion at 85 degree C in 1% Na sub(2)CO sub(3) whereas sponge spicules, which are generally larger than diatoms, take longer to dissolve. Because sponge spicules comprise a significant fraction of total amorphous silica extracted, we hypothesize that sponge spicules, which on average are larger than diatoms and require a longer time for complete dissolution, may constitute an important sink for BSi in Florida lakes.
AN: 2907154
840 of 1521
TI: Earth Observation System (EOS): Ecological priorities and observation planning: 1 - Priorities.
AU: Kondrat'-ev,-K.Ya.
AF: Ecol. Security Cent., Russian Acad. Sci., St. Petersburg, Russia
SO: SOV.-J.-REMOTE-SENS. 1993. vol. 10, no. 3, pp. 519-544
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The paper describes the scientific priorities which form the basis for the development of the American global ecological monitoring system (EOS). Key value is placed on studies of energy and water cycles and the biogeochemical cycles of carbon, nitrogen and sulphur together with the implementation of an ecosystem approach to observation planning. Global monitoring of bioproductivity on land and in the Pacific Ocean (the dynamics of forests, phytoplankton, etc.) is amongst the primary problems. Polar regions require particular attention (essentially in the context of the effect of the dynamics of the cryosphere on the climate). Corresponding requirements on the observational data are discussed in detail.
AN: 2906596
841 of 1521
TI: Biological nitrogen fixation (acetylene reduction) associated with decomposing Avicennia marina leaves in the Beachwood Mangrove Nature Reserve.
AU: Mann,-F.D.; Steinke,-T.D.
AF: Estuar. and Mar. Group, Dep. Bot., Univ. Durban-Westville, Priv. Bag X54001, Durban 4000, South Africa
SO: S.-AFR.-J.-BOT.-S.-AFR.-TYDSKR.-PLANTKD. 1992. vol. 58, no. 6, pp. 533-536
LA: English
AB: Nitrogen fixation of decomposing Avicennia marina (Forssk.) Vierh. leaves was studied over a period of 16 weeks under exposed and submerged conditions. Rates of acetylene reduction activity (ARA) were highest under exposed conditions and reached a maximum after three to four weeks. Percentage total nitrogen increased during decomposition, the increase being greatest under submerged conditions, but this was not directly related to nitrogen fixation. Bacteria were considered to be the main agents of nitrogen fixation. Rates of decomposition were highest under exposed conditions. The contribution of nitrogen fixation to the nitrogen budget is significant.
AN: 2905618
842 of 1521
TI: Distribution of organic carbon in sediments from the Arabian Sea.
AU: Paropkari,-A.L.; Mascarenhas,-A.; Prakashbabu,-C.
CA: National Inst. of Oceanography, Dona Paula (India)
SO: TECH.-REP.-NATL.-INST.-OCEANOGR.-INDIA. 1991. no. 18, 46 pp
RN: NIO/TR-18/91 (NIOTR1891)
LA: English
ER: M (Marine)
AB: Many earlier studies on the distribution of organic carbon in the Arabian Sea sediments have projected contradictory opinions on the factors favouring accumulation and preservation of organic carbon by these sediments. An attempt is made to reevaluate the role of various sedimentary parameters on the surface distribution of organic carbon in the Arabian Sea. The revaluation identifies 2 regional bands of organic-rich sediments -- one along the slope of the Arabian Peninsula and the other along the western slope of India. The organic carbon distribution mirrors the surface productivity -- high in the peripheral portions and low in the open ocean, suggesting that it derives mainly from marine origin. A perfect coincidence of organic enrichment on the slopes with the oxygen minimum zone (150-150 m) clearly demonstrates the influence of anoxic waters on organic enrichment. Bottom water anoxia (though a principal factor for organic enrichment on the slopes) and its interplay with other depositional parameters cumulatively determines the "degree of preservation" and fixes the location of organic enrichment along the slopes.
AN: 2905562
843 of 1521
TI: Initial burial and subsequent degradation of sedimented phytoplankton: Relative impact of macro- and meiobenthos.
AU: Webb,-D.G.; Montagna,-P.A.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, NS B3H 4J1, Canada
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1993. vol. 166, no. 2, pp. 151-163
LA: English
ER: M (Marine)
AB: The initial burial (transfer through the sediment-water interface) and subsequent degradation of sedimented phytoplankton was examined in the laboratory in sediments containing meiofauna, both with and without macrofauna, over a 10-day period. Burial and degradation were monitored by following changes in vertical profiles of Chl a and phaeopigments in sediment columns with and without an addition of senescent Skeletonema costatum Greville (Cleve) cells to the sediment surface. The macrofauna present in the cores consisted of a subsurface deposit-feeder assemblage typical of organically enriched habitats. Upon diatom addition, the visual redox potential discontinuity (RPD) rose to or near the sediment surface. Chl a and phaeopigment levels increased 6 and 3 days after diatom addition, respectively, with no difference in concentrations in the presence or absence of macrofauna. These increases appeared to be confined to the top 5 mm of sediment. Overall, phaeopigment concentrations were higher in cores containing macrofauna. A minimum of 83% of the added Chl a was transferred through the sediment-water interface in 10 days. In organically enriched habitats, the initial burial and subsequent degradation of sedimented phytoplankton appears to be a process dominated by the meiofaunal and microbial communities, and unaffected by subsurface deposit-feeding macrofauna.
AN: 2902683
844 of 1521
TI: The role of planktonic algae in the cycling of Zn and Cu in a productive soft-water lake.
AU: Reynolds,-G.L.; Hamilton-Taylor,-J.
AF: Inst. Environ. and Biol. Sci., Univ. Lancaster, Lancaster, LA1 4YQ, UK
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 8, pp. 1759-1769
LA: English
ER: F (Freshwater)
AB: Concentrations of dissolved Zn and Cu were measured alongside biomass (algal numbers, organic C, and Chl a) and dissolved micronutrients (P, Si) over an 8-week period, covering a pronounced bloom of the diatom, Asterionella . The distribution of dissolved Zn appears to be affected by algal cycling in two ways: in the period up to and including the diatom maximum, dissolved Zn correlates (P < 0.01) positively with phosphate and silicate, indicating atomic C:P:Zn ratios of 106:1:0.034, and negatively with Chl a; and following stratification, epilimnetic concentrations are significantly (P < 0.01) less than those in the hypolimnion. Dissolved Cu distributions are unaffected by the spring diatom bloom. The Zn and Cu contents of the diatom standing crop were also determined by elemental analysis of suspended particulate material in two consecutive years, providing independent estimate of metal stoichiometry. Mass budgets indicate a substantial removal and transfer to the sediments of Zn via phytoplankton, but a negligible effect on the cycling of Cu.
AN: 2902540
845 of 1521
TI: External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay.
AU: Magnien,-R.E.; Summers,-R.M.; Sellner,-K.G.
AF: Maryland Dep. Environ., Chesapeake Bay and Watershed Manage. Adm., 2500 Broening Highway, Baltimore, MD 21224, USA
CO: 5. Int. Congr. of Ecology (INTECOL), Yokahama (Japan), Aug 1990
SO: COUPLINGS-BETWEEN-WATERSHEDS-AND-COASTAL-WATERS.-FIFTH-INTERNATIONAL-CONGRESS-OF-ECOLOGY-INTECOL. 1991. vol. 15, no. 4 pp. 497-516
ST: ESTUARIES. vol. 15, no. 4
NT: Dedicated issue, organized by Valiela, I.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: External nutrient loadings, internal nutrient pools, and phytoplankton production were examined for three major subsystems of the Chesapeake Bay Estuary - the upper Mainstem, the Patuxent Estuary, and the Potomac Estuary - during 1985-1989. The atomic nitrogen to phosphorus ratios (TN:TP) of total loads to the Mainstem, Patuxent, and the Potomac were 51, 29 and 35, respectively. Most of these loads entered at the head of the estuaries from riverine sources and major wastewater treatment plants. Approximately 7-16% of the nitrogen load entered the head of each estuary as particulate matter in contrast to 48-69% for phosphorus. This difference is hypothesized to favor a greater loss of phosphorus than nitrogen through sedimentation and burial. This process could be important in driving estuarine nitrogen to phosphorus ratios above those of inputs. Water column TN:TP ratios in the tidal fresh, oligohaline, and mesohaline salinity zones of each estuary ranged from 56 to 82 in the Mainstem, 27 to 48 in the Patuxent, and 72 to 126 in the Potomac. A major storm event in the Potomac watershed was shown to greatly increase the particulate fraction of nitrogen and phosphorus and lower the TN:TP in the river-borne loads. The load during the month that contained this storm (November 1985) accounted for 11% of the nitrogen and 31% of the phosphorus that was delivered to the estuary by the Potomac River during the entire 60-month period examined here.
AN: 2902424
846 of 1521
TI: Nutrient flux in a landscape: Effects of coastal land use and terrestrial community mosaic on nutrient transport to coastal waters.
AU: Correll,-D.L.; Jordan,-T.E.; Weller,-D.E.
AF: Smithson. Environ. Res. Cent., P.O. Box 28, Edgewater, MD 21037, USA
CO: 5. Int. Congr. of Ecology (INTECOL), Yokahama (Japan), Aug 1990
SO: COUPLINGS-BETWEEN-WATERSHEDS-AND-COASTAL-WATERS.-FIFTH-INTERNATIONAL-CONGRESS-OF-ECOLOGY-INTECOL. 1991. vol. 15, no. 4 pp. 431-442
ST: ESTUARIES. vol. 15, no. 4
NT: Dedicated issue, organized by Valiela, I.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Long-term interdisciplinary studies of the Rhode River estuary and its watershed in the Mid-Atlantic Coastal Plain of North America have measured fluxes of nitrogen and phosphorus fractions through the hydrologically-linked ecosystems of this landscape. These ecosystems are upland forest, cropland, and pasture; streamside riparian forests; floodplain swamps; tidal brackish marshes and mudflats; and an estuarine embayment. Croplands discharged far more nitrogen per hectare in runoff than did forests and pastures. However, riparian deciduous hardwood forest bordering the cropland removed over 80 percent of the nitrate and total phosphorus in overland flows and about 85 percent of the nitrate in shallow groundwater drainage from cropland. Nevertheless, nutrient discharges from riparian forests downslope from croplands still exceeded discharges from pastures and other forests. The atomic ratio of nitrogen to phosphorus discharged from the watersheds into the estuary was about 9 for total nutrients and 6 for inorganic nutrient fractions. Such a low N:P ratio would promote nitrogen rather than phosphorus limitation of phytoplankton growth in the estuary. Estuarine tidal marshes trapped particulate nutrients and released dissolved nutrients. Subtidal mudflats in the upper estuary trapped particulate P, released dissolved phosphate, and consumed nitrate. This resulted in a decrease in the ratio of dissolved inorganic N:P in the estuary. However, the upper estuary was a major sink for total phosphorus due to sediment accretion in the subtidal area. The nitrogen and phosphorus discharges into the Rhode River, although a small fraction of total loadings to the watershed, were large enough to cause seriously overenriched conditions in the upper estuary.
AN: 2902313
847 of 1521
TI: A comparison of ecosystem dynamics in freshwater wetlands.
AU: Hopkinson,-C.S.,Jr.
AF: Ecosyst. Cent., Mar. Biol. Lab., Woods Hole, MA 02543, USA
CO: 5. Int. Congr. of Ecology (INTECOL), Yokahama (Japan), Aug 1990
SO: COUPLINGS-BETWEEN-WATERSHEDS-AND-COASTAL-WATERS.-FIFTH-INTERNATIONAL-CONGRESS-OF-ECOLOGY-INTECOL. 1991. vol. 15, no. 4 pp. 549-562
ST: ESTUARIES. vol. 15, no. 4
NT: Dedicated issue, organized by Valiela, I.
LA: English
ER: F (Freshwater)
AB: The effects of system closure on the dynamics of productivity and nutrient cycling are examined in four wetlands that differ in plant growth form and magnitudes and sources of water input and nutrient loading. Dynamics in relatively closed ombrotrophic Carex marsh and Taxodium swamp systems from Okefenokee Swamp are compared to those in open, rheotrophic riparian systems. The riparian systems examined include Zizaniopsis marshes along the tidal freshwater portion of the Altamaha River in Georgia and a mature Taxodium-Nyssa swamp along the Cache River in Illinois. Water budgets in the ombrotrophic systems are dominated by precipitation inputs while in the riparian wetlands they are dominated by overbank flooding. Nutrient loading to the open and closed systems differs by only two orders of magnitude, the former depending on atmospheric inputs and the latter depending on tidal and riverine inputs. Comparisons of nutrient import, export, and retention indicate that greater than 90% of inorganic nutrients are retained in the closed systems while less than 5% are retained in the open systems. Nutrient budgets for wetland vegetation, including aboveground uptake, root uptake, leaching, death, and translocation, are constructed. Strong differences in nutrient conservation within plant communities are found between marsh and forested closed systems and between open and closed systems as a whole. There is the indication that nutrients turn over more rapidly and nutrient cycles are less retentive and conservative as systems become more open and nutrient inputs increase.
AN: 2902170
848 of 1521
TI: Loss of nutrients from catchments and their ecological impacts in the Peel-Harvey estuarine system, Western Australia.
AU: McComb,-A.J.; Humphries,-R.
AF: Environ. Sci., Murdoch Univ., Murdoch, W.A. 6009, Australia
CO: 5. Int. Congr. of Ecology (INTECOL), Yokahama (Japan), Aug 1990
SO: COUPLINGS-BETWEEN-WATERSHEDS-AND-COASTAL-WATERS.-FIFTH-INTERNATIONAL-CONGRESS-OF-ECOLOGY-INTECOL. 1991. vol. 15, no. 4 pp. 529-537
ST: ESTUARIES. vol. 15, no. 4
NT: Dedicated issue, organized by Valiela, I.
LA: English
AB: Rivers draining coastal-plain soils with a low phosphorus-binding capacity load nutrients into the estuarine system in winter. Phosphorus is largely by diatom blooms and recycled via the sediments to support growth, during the warmer months, of blue-green algae in Harvey Estuary or macroalgae in Peel Inlet. The magnitude of blue-green algae (Nodularia ) blooms is related to the amount of river water entering in winter; blooms collapse as salinities rise toward that of the ocean. For macroalgae the relationship between light and nutrient availability is of critical importance. Control measures are concerned with reducing phosphorus loads from catchments and increasing water exchange with the ocean through the proposed construction of a new channel.
AN: 2902127
849 of 1521
TI: The role of humic substances in the mobilization of mercury from watersheds.
AU: Mierle,-G.; Ingram,-R.
AF: Ontario Minist. Environ., Dorset Res. Cent., P.O. Box 39, Dorset, ON P0A 1EO, Canada
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 349-357
LA: English
ER: F (Freshwater)
AB: The total Hg concentration was estimated in eight inflowing streams from two headwater lakes and catchments in Ontario over a 2-yr period. Marked seasonal patterns in all brown water streams were evident, with highest levels usually occurring in the early fall and early spring. The seasonal pattern and the estimated export of Hg was most closely related to color, a measure of humic matter in the water. The data suggest that humic matter controls the solubility and watershed export of Hg deposited in precipitation.
AN: 2901008
850 of 1521
TI: The coupling of mercury and organic matter in the biogeochemical cycle--towards a mechanistic model for the boreal forest zone.
AU: Meili,-M.
AF: Inst. Limnol., Uppsala Univ., Box 557, 75122 Uppsala, Sweden
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 333-347
LA: English
ER: F (Freshwater)
AB: In boreal forest lakes, high Hg concentrations in fish are common, even in remote areas. In this paper, the effects of atmospheric Hg pollution in Sweden are synthesized and related to a concept based on the strong interaction of Hg with biogenic matter (Hg/B). Based on this concept, a compartment model is developed to predict concentrations, pool sizes, flux rates and turnover times of Hg along the biogeochemical cycle, including atmosphere, forest soils, surface runoff, lake waters, and aquatic biota. The aim is to provide a conceptual framework, both for a comprehensive mechanistic model, and for predictions from readily available information, such as regional data on acid deposition, air temperature and surface runoff, and local data on the trophic status of lakes with respect to humus and nutrient concentrations. It suggests a strong influence of climate on the susceptibility of soil and lake ecosystems in the boreal region to Hg contamination.
AN: 2900982
851 of 1521
TI: Laboratory production of bromoform, methylene bromide, and methyl iodide by macroalgae and distribution in nearshore southern California waters.
AU: Manley,-S.L.; Goodwin,-K.; North,-W.J.
AF: Dep. Biol., California State Univ., Long Beach, CA 90840, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 8, pp. 1652-1650
LA: English
ER: M (Marine)
AB: Production rates of bromoform (CHBr sub(3)), methylene bromide (CH sub(2)Br sub(2)), and methyl iodide (CH sub(3)I) were measured in the laboratory for 11 species of marine macroalgae. Production rates of the volatile bromomethanes extrapolated to a global scale suggest that marine macroalgae produce 2 x 10 super(11) g Br/yr, 98% of which is bromoform. Laminarians (kelps) produce 61% of this organic Br. These calculations suggest that marine macroalgae are important in the biogeochemical cycling of Br. Seawater concentrations of CHBr sub(3), CH sub(2)Br sub(2), and CH sub(3)I were determined from various southern California coastal locales. High concentrations were measured in seawater from the canopy and the bottom of a dense bed of Macrocystis) as compared to other sites. Surface seawater concentrations of these halomethanes showed a strong cross-shore gradient with the highest concentration in the kelp canopy and the lowest at 5 km offshore. Seawater adjacent to decaying macroalgae on the bottom of a submarine canyon was not enriched in halomethanes relative to surface water. Water exiting a productive estuary was enriched only with CH sub(2)Br sub(2), although two algal species that are abundant there (Ulva) and Enteromorpha ) showed high laboratory production rates of both CHBr sub(3) and CH sub(2)Br sub(2).
AN: 2899845
852 of 1521
TI: Specific rates of net methylmercury production in lake sediments.
AU: Matilainen,-T.; Verta,-M.; Niemi,-M.; Uusi-Rauva,-A.
AF: Dep. Limnol., Univ. Helsinki, Viikki, E-house, SF-00710 Helsinki, Finland
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 595-605
LA: English
ER: F (Freshwater)
AB: Specific rates of Hg ( super(203)HgCl sub(2)) methylation and MeHg ( super(14)CH sub(3)HgI) demethylation in aerobic and anaerobic conditions were determined in samples of surface sediments (0 to 2 cm) taken from five small headwater lakes in Southern Finland. The highest rates of methylation were measured in anaerobic conditions. however, the importance of aerobic methylation increased with increasing Fe and Mn content in sediment. There was little difference between aerobic and anaerobic demethylation. The results demonstrate that the net MeHg production in lake sediments depends on the individual characteristics of the lake, particularly pH and sediment properties. These characteristics seem to affect demethylation in anaerobic conditions and methylation in aerobic conditions.
AN: 2897894
853 of 1521
TI: Mercury cycling in a northern Wisconsin seepage lake: The role of particulate matter in vertical transport.
AU: Hurley,-J.P.; Watras,-C.J.; Bloom,-N.S.
AF: Bur. Res., Wisconsin Dep. Natural Resour., 3911 Fish Hatchery Rd., Fitchburg, WI 53711, USA
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER,-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 543-551
LA: English
ER: F (Freshwater)
AB: During summer stratification, total mercury (Hg sub(T)) reached maximum concentrations in the O sub(2)-depleted, hypolimnion of Little Rock Lake, WI. Initially, the hypolimnetic increase was attributed solely to redox-controlled release of Hg from bottom sediments. However, subsequent depth profiles of Hg indicated that hypolimnetic Hg enrichment could also result from the downward transport and recycling of particulate Hg prior to incorporation in the sediments. Contrasts between Fe and Hg cycles in this lake reinforce this notion. Increases in hypolimnetic Fe were observed during both summer and winter O sub(2) decreases. In contrast, hypolimnetic Hg concentrations declined during winter. In the ice-free season, the distribution of particulate mercury (Hg sub(P)) correlated with the distribution of chlorophyllous particulates in this lake, re-emphasizing the importance of biotic processes in controlling Hg cycling in the hypolimnion.
AN: 2897861
854 of 1521
TI: Sources, cycling and fate of contaminants in Chesapeake Bay.
AU: Sanders,-J.G.; Riedel,-G.F.
AF: Acad. Nat. Sci., Benedict Estuarine Res. Lab., Benedict, MD 20612, USA
CO: 16. Bienn. Conf. of the Int. Assoc. on Water Pollution Research and Control, Washington, DC (USA), 24-30 May 1992
SO: WATER-QUALITY-INTERNATIONAL-'-92-WASHINGTON-DC,-1992. Suzuki,-M.;et-al.-eds.. 1992. vol. 26, no. 1-12 pp. 2645-2652
ST: WATER-SCI.-TECHNOL. vol. 26, no. 1-12
NT: Part 6.
LA: English
ER: B (Brackish)
AB: In order to predict and control the impacts of contaminants to coastal ecosystems like the Chesapeake Bay, we must first understand the geochemical, physical, and biological factors that control contaminant transport, transformation, uptake, and fate. Some processes exert control over broad groups of contaminants; the importance of others varies with specific contaminants. Many of these processes are well known and are amenable to predictive modeling, while others are less well understood and require further attention and research. Most important for the future protection of the Chesapeake Bay, and other coastal ecosystems, will be a coordinated approach (both in the research that must be conducted and in the management decision that must be made), linking scientists of many disciplines with those changed with ecosystem protection.
AN: 2896945
855 of 1521
TI: Modelling the Phanerozoic carbon cycle and climate: Constraints from the super(87)SR/ super(86)SR isotopic ratio of seawater.
AU: Francois,-L.M.; Walker,-J.C.G.
AF: Space Phys. Res. Lab., Dep. Atmos., Oceanic, and Space Sci., Dep. Geol. Sci., Univ. Michigan, Ann Arbor, MI 48109, USA
SO: AM.-J.-SCI. 1992. vol. 292, no. 2, pp. 81-135
LA: English
ER: M (Marine)
AB: A numerical model describing the coupled evolution of the biogeochemical cycles of carbon, sulfur, calcium, magnesium, phosphorus, and strontium has been developed to describe the longterm changes of atmospheric carbon dioxide and climate during the Phanerozoic. The emphasis is on the effects of coupling the cycles of carbon and strontium. Various interpretations of the observed Phanerozoic history of the seawater super(87)Sr/ super(86)Sr ratio are investigated with the model. More specifically, the abilities of continental weathering, volcanism, and surface lithology in generating that signal are tested and compared. It is suggested that the observed fluctuations are mostly due to a changing weatherability over time. It is shown that such a conclusion is very important for the modelling of the carbon cycle.
AN: 2895461
856 of 1521
TI: Rates of amino acid uptake and mineralization in Resurrection Bay (Alaska) sediments.
AU: Sugai,-S.F.; Henrichs,-S.M.
AF: Inst. Mar. Sci., Sch. Fish. and Ocean Sci., Univ. Alaska, Fairbanks, AK 99775-1080, USA
SO: MAR.-ECOL.-PROG.-SER. 1992. vol. 88, no. 2-3, pp. 129-141
NT: Bibliogr.: 25 ref.
LA: English
ER: M (Marine)
AB: The rates of uptake and mineralization of glutamic acid, alanine, lysine, serine and glycine were measured in sediments from Resurrection Bay, Alaska, USA, using super(14)C-labeled amino acids. Amino acid concentrations and specific activities were determined by high performance liquid chromatography. The fate of radiolabeled amino acids added to killed control sediments was also investigated. Free amino acids were lost from the dissolved pool by both bacterial uptake and adsorption to sediment particles. Adsorption was the dominant process for the basic amino acid lysine and was responsible for about half of the glutamic acid and alanine removal from solution. Rates of bacterial mineralization of porewater amino acids, calculated using a model which corrects for the effects of adsorption, were 8 (glutamic acid), 1 (alanine), 0.7 (lysine), 1 (serine) and 3 (glycine) nmol/cm super(3) sediment/d.
AN: 2892154
857 of 1521
TI: Decomposition and release of elements from zooplankton debris.
AU: Lee,-B.-G.; Fisher,-N.S.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
SO: MAR.-ECOL.-PROG.-SER. 1992. vol. 88, no. 2-3, pp. 117-128
NT: Bibliogr.: 55 ref.
LA: English
ER: M (Marine)
AB: In experiments examining the retention of trace elements in decomposing zooplankton debris, the rates of C degradation and metal release from radiolabeled copepod fecal pellets and carcasses were measured for up to 1 mo using radiotracers. Fecal pellets incubated at 18 and 2 degree C retained 35 to 40% and 80% of their super(14)C, respectively, after 30 d. Carcasses retained only 13 to 18% and 28 to 38% of their super(14)C after 18 d and 18 and 2 degree C, respectively. Leaching of super(14)C from fecal pellets and carcasses as DO super(14)C accounted for about half of the super(14)C loss, even in the absence of microbial activity. Proportionately more of the super(14)C from carcasses was microbially oxidized to super(14)CO sub(2) than super(14)C from fecal pellets. Release of the particle-reactive transuranic element super(241)Am from fecal pellets was unaffected by microbial activity while release of super(75)Se and super(65)Zn from both fecal pellets and carcasses increased with microbial activity and closely followed super(14)C loss. Release rates of all elements decreased exponentially over time, with the most pronounced decreases occurring within the first 6 d. Retention half-times (t sub(r is equivalent )'s) of super(241)Am were greater than or equal to 48 d in fecal pellets. By contrast, the t sub(r is equivalent )'s for super(65)Zn ranged from 2.1 to 13.5 d in fecal pellets and both super(65)Zn and super(75)Se had t sub(r is equivalent )'s of only about 1 d in carcasses.
AN: 2892122
858 of 1521
TI: Calcite precipitation and solution in Lake Laacher See.
AU: Friebertshaeuser,-D.; Moegling,-A.; Bahring,-B.
SO: LIMNOLOGY-OF-EIFEL-MAAR-LAKES. Scharf,-B.W.;Bjoerk,-S.-eds. STUTTGART-FRG SCHWEIZERBART'-SCHE-VERLAGSBUCHHANDLUNG 1992. no. 38 pp. 85-102
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 38
LA: English
ER: F (Freshwater)
AB: The annual development of carbonate precipitation and solution in the volcanic crater-lake Laacher See was studied by investigations of water chemistry, sediments collected in sediment traps, and the application of a thermodynamic model. The chemical data show a clear relation between calcite saturation and water temperature. During the summer temperature maximum a supersaturation of up to 10-fold develops as a result of CO sub(2)- diffusion and decreased calcite solubility. The precipitation of calcite is triggered by the growth of diatoms of the genera Cyclotella) and Synedra in spring and early summer. During the precipitation period (April-July) the diminution of the planktonic diatoms is balanced by a rising supersaturation. The preservation of the calcite crystals is strongly coupled to the saturation in the water column. The morphology and surface of the calcite crystals proves a partial solution of calcite in the undersaturated, deeper water. These effects explain the depth dependent zonation of the bottom sediments that were found in earlier investigations.
AN: 2891245
859 of 1521
TI: (Proteins, carbohydrates, and chlorophyll a of the particulate organic matter in three different oceanic environments: Sea of Portugal, California Gulf and NW Baja California Sur.).
OT: Proteinas, carbohidratos y clorofila a de la materia organica particulada, en tres diferentes ambientes oceanicos: Mar de Portugal, Golfo de California y NW de Baja California Sur
AU: Lechuga-Deveze,-C.H.; Ayala-Rocha,-B.; Garate-Lizarraga,-I.
AF: Cent. Invest. Biol. Baja California Sur, Apdo. Postal 128, 23000 La Paz, B.C.S., Mexico
SO: AN.-INST.-CIENC.-MAR-LIMNOL.-UNIV.-NAC.-AUTON.-MEX. 1989. vol. 16, no. 1, pp. 147-156
LA: Spanish
ER: M (Marine)
AB: A survey on the protein and carbohydrate content of the particulate organic matter in 3 different oceanic environments: the Atlantic Ocean off Portugal, the California Gulf and the Pacific Ocean off Baja California was conducted. The protein concentration of the detrital particulate matter was quite constant for the 3 areas (31.9 mg prot/m super(3)); the carbohydrate concentrations ranged between 5.4 and 117 mg carbohydrate/m super(3). It is presumed that proteins and carbohydrates of the bacteria/detritus fraction might be an important energy source for other members of the food chain, and this energy input is being modified by variations in the source and concentration of particulate carbohydrates.
AN: 2889081
860 of 1521
TI: Behavior and dynamic balance of manganese during spring bloom in Funka Bay, Japan.
AU: Kudo,-I.; Ohyama,-T.; Nakabayashi,-S.; Kuma,-K.; Matsunaga,-K.
AF: Dep. Chem., Fac. Fish., Hokkaido Univ., Hakodate 041, Japan
SO: MAR.-CHEM. 1992. vol. 40, no. 3-4, pp. 273-289
LA: English
ER: M (Marine)
AB: The distribution of manganese was investigated during a spring bloom in Funka Bay by chemically segregating dissolved, soluble and refractory Mn. The concentration of dissolved Mn changed slightly owing to assimilation by phytoplankton and dissolution of aerosol particles. A simple mass balance was adopted in this bloom period to clarify the dynamics of Mn in the euphotic zone. From this result, the assimilated Mn was estimated to be 10.6 mu mol/m super(2)/day. However, it was observed that the total Mn increased significantly despite the removal of Mn by settling. This Mn increase was attributable to atmospheric transport of fine particles from land close to this bay.
AN: 2884760
861 of 1521
TI: Seasonal iron cycling in the salt-marsh sedimentary environment: The importance of ligand complexes with Fe(II) and Fe(III) in the dissolution of Fe(III) minerals and pyrite, respectively.
AU: Luther,-G.W.,III; Kostka,-J.E.; Church,-T.M.; Sulzberger,-B.; Stumm,-W.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: MAR.-CHEM. Millero,-F.J.-ed. 1992. vol. 40, no. 1-2, pp. 81-103
NT: Spec. Iss.: Progress in Mar. Chem.
LA: English
ER: M (Marine)
AB: A biogeochemical cycle is proposed for the reactivity of iron in salt-marsh sediments. The main reactions of the iron cycle are: (1) solubilization of Fe(III) by organic ligands; (2) reduction of soluble Fe(III) to Fe(II) by these ligands, soluble reduced sulfur or solid phase reduced sulfur; (3) the oxidation of the resulting Fe(II) (complexed to organic chelates) by Fe(III) minerals; (4) the formation of iron sulfide minerals when dissolved sulfide is in excess. The cycle of iron solubilization will continue as long as bacteria and/or plants produce organic ligands. The cycle will stop when sulfate reduction rates are high and organic ligand production is low. At this point soluble hydrogen sulfide reacts with Fe(II) and Fe(III) to form sulfide minerals. Penetration of O sub(2) into the surface sediments will also oxidize Fe(II) to Fe(III) with subsequent formation of Fe(III) (oxy)hydroxide minerals. The reactions which represent the iron cycle indicate that the iron mineral system has substantial acid/base buffering capacity.
AN: 2884617
862 of 1521
TI: Sampling and experimental challenges for the next decade in marine organic chemistry - a prospectus.
AU: Wakeham,-S.G.
AF: Skidaway Inst. Oceanogr., P.O. Box 13687, Savannah, GA 31416, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 239-242
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Major advances in marine organic chemistry during the past decade have come on three fronts. The application of modern analytical tools has made possible measurements of many more and more complex organic compounds in seawater and sediments than was previously possible. New sampling techniques have provided new and important sample types for analysis of their organic composition. Manipulative experiments to study processes are becoming common. In order to keep progressing into the future, however, several areas must see continued advancement. Fundamental steps must be taken to better sample and characterize the large pool of dissolved and colloidal organic material. Improved in situ sensing systems for continuous and real-time measurements of dissolved components would greatly help in this characterization. Increased use of time-series sediment traps for organic geochemical investigations is needed to enhance our understanding of temporal variations in organic compound flux and cycling. Increased emphasis on in situ experimentation will be needed in order to understand mechanisms and rates for biogeochemical processes in which organic matter participates.
AN: 2883988
863 of 1521
TI: Importance of isotope measurements in marine organic geochemistry.
AU: Druffel,-E.R.M.; Williams,-P.M.
AF: Chem. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 209-215
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: We present here some specific areas of research, prefaced by brief and selected reviews, that address the cycling of organic matter in the marine environment. These are areas in which isotopic signatures will provide vital answers or clues.
AN: 2883963
864 of 1521
TI: Organic matter in the water column: Future research challenges.
AU: Lee,-C.; Wakeham,-S.G.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 95-118
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Recent research has greatly changed our knowledge of processes affecting organic matter in the water column. Here we review some of this recent research and suggest several areas which are particularly challenging for future studies. Major areas discussed are newly developed methods of dissolved organic carbon (DOC) analysis and the implications of the results, and the potential significance of organic colloids in seawater. Recent advances in techniques for the analysis of small, labile organic molecules and in radiotracer techniques used to follow rates and mechanisms of biological consumption are also discussed. Ocean-atmosphere transport and photochemical processes can act as both sources and sinks of organic matter in the sea. This is an area where significant progress has been made recently. Finally, we discuss current knowledge of river transport to the oceans and particle sedimentation in the sea as well as some of the limitations on this knowledge.
AN: 2883887
865 of 1521
TI: Global biogeochemical cycles: Progress and problems.
AU: Hedges,-J.I.
AF: Sch. Oceanogr., WB-10 Univ. Washington, Seattle, WA 98195, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 67-93
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Progress in understanding global biogeochemical cycles has been made on many fronts of organic geochemical study over the last decade. Key questions, however, remain to be answered. These include the following: (1) Is kerogen completely remineralized during the weathering of sedimentary rocks? (2) What types of refractory biochemicals are made by plants? (3) What factors control export of organic matter from the land to the ocean? (4) What are the components, sources and fates of organic materials dissolved in seawater? (5) What types of organic substances accumulate in deltaic and coastal marine sediments? (6) Is better understanding of global biogeochemical cycles possible through new conceptual approaches?
AN: 2883870
866 of 1521
TI: Biomarker and molecular paleontology working group report.
AU: Farrington,-J.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 51-65
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Organic matter in marine sediments originates from autochthonous primary production in the oceans and from allochthonous riverine and eolian contributions. Allochthonous inputs include organic matter of direct biological origin augmented by material from reworked geological sources such as weathered kerogens, petroleum seepages and hydrothermal vents. These diverse inputs of organic matter may survive unaltered, or may be modified and overprinted by contributions from secondary producers and by physicochemical transformation processes. Thus, the sedimentary organic matter is derived from organisms and geological sources either (a) selectively preserved, but otherwise unaltered, or (b) modified by biochemical activity and/or chemical alteration. A major goal of molecular paleontologists is to deconvolute these signals in the sedimentary record and to assess, interpret and distinguish them in terms of their response to paleoenvironmental and paleoecological factors and to variations in biogeochemical cycles. These objectives must be addressed at a range of spatial and temporal scales, with broad emphases on both regional and global issues and on both contemporary and ancient sediments.
AN: 2883851
867 of 1521
TI: Macromolecular organic matter working group report.
AU: Farrington,-J.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 39-50
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: In the following discussion, macromolecular organic matter (MOM) is defined as organic substances larger than biochemical monomers (e.g. simple amino acids and sugars) and ranging up to aqueous colloids. In the broadest sense, MOM may consist of loosely aggregated assemblages of smaller molecules as well as discrete covalently bonded structures. It is thought that MOM probably is composed of both biopolymers and humic substances, which are degradation products of biopolymers. Although MOM can occur either in dissolved or particulate form, the bulk of the following discussion deals with the MOM component of dissolved organic matter (DOM) in seawater, which by definition is not removed by less than 0.5 mu m filters. The study of MOM is crucial for understanding organic matter sources and sinks in the ocean as well as for delineating the vast number of transformation processes that organic substances undergo within the water column and sediments. Although largely uncharacterized as yet, MOM apparently accounts for the major portion of DOM, which is the largest reservoir of organic carbon in the sea and comparable in carbon content to atmospheric CO sub(2). MOM thus is important in global biogeochemical cycles including the partitioning of CO sub(2) among the various active reservoirs.
AN: 2883828
868 of 1521
TI: Water column working group report.
AU: Farrington,-J.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: DOC/DON Workshop, Honolulu, HI (USA), 15-19 Jul 1991
SO: MARINE-ORGANIC-GEOCHEMISTRY:-REVIEW-AND-CHALLENGES-FOR-THE-FUTURE. Farrington,-J.W.-ed. 1992. vol. 39, no. 1-3 pp. 15-25
ST: MAR.-CHEM. vol. 39, no. 1-3
LA: English
ER: M (Marine)
AB: Organic matter in the oceanic water column is one of the most interactive organic pools on the Earth's surface because of the interfaces between the ocean and the atmosphere, sediments, and biota. With this in mind, three general questions are of central importance to improving our understanding of the role that water column processes play in oceanic chemistry. (1) What is the nature of oceanic organic matter? (2) What processes control water column organic chemistry? (3) How does water column organic chemistry in turn influence other oceanographic processes and global biogeochemical cycles?
AN: 2883791
869 of 1521
TI: (Carbonate sediments of the continental shelves of Paraiba State.).
OT: Sedimentos carbonaticos da plataforma continental do Estado da Paraiba
AU: Barbosa,-C.M.B.M.
AF: Dep. Quim. Aplicada, Univ. Fed. Pernambuco, 5000 Recife, PE, Brazil
SO: TRAB.-OCEANOGR.-UNIV.-FED.-PERNAMBUCO. 1989. vol. 20, pp. 125-144
LA: Portuguese
ER: M (Marine)
AB: Carbonate sediments stemming from massive and ramified coralline algae, together with significant amount of Halimeda , lie on the narrow continental shelf of the engaged area. The terrigenous sediments which are the mostly composed of quartz sands with organic fragments strech along the shelf boundary to a depth of 15 meters. The calcium carbonate content is very high and increases towards the offshore area. The lack of an important terrigenous sedimentation together with the favorable climatic and oceanographic conditions are responsible for the concentration of this significant organic calcareous deposit.
AN: 2882541
870 of 1521
TI: Disturbance of the phosphorus cycle: A case of indirect effects of human activity.
AU: Caraco,-N.F.
AF: Inst. Ecosyst. Stud., The Mary Flagler Cary Arbor., Box AB, Millbrook, NY 12545, USA
SO: TRENDS-ECOL.-EVOL. 1993. vol. 8, no. 2, pp. 51-54
LA: English
ER: F (Freshwater)
AB: Phosphorus (P) often limits primary productivity of aquatic systems. Humans have altered the P cycle in aquatic systems, directly, by mining P-rich rock, and indirectly, through the manipulation of other element cycles and the alteration of aquatic food webs. Aquatic ecologists are becoming increasingly aware of the importance of these indirect alterations to biogeochemical cycles. Quantitative predictions of these indirect effects will be an important focus of future studies.
AN: 2881168
871 of 1521
TI: Nutrient transformations in sediments as influenced by oxygen supply.
AU: Moore,-P.A.,Jr.; Reddy,-K.R.; Graetz,-D.A.
AF: Southeast Res. and Ext. Cent., Univ. Arkansas, P.O. Box 3508, Monticello, AR 71655, USA
SO: J.-ENVIRON.-QUAL. 1992. vol. 21, no. 3, pp. 387-393
LA: English
ER: F (Freshwater)
AB: The oxidation status of sediments greatly affects biogeochemical processes. The objective of this study was to determine the influence of various levels of O sub(2) on nutrient transformations in lake sediments. Decomposition of sediment organic matter was evaluated under varying levels of O sub(2). Bulk sediment samples obtained from a hypereutrophic lake in central Florida were incubated in stirred microcosms at 25 degree C for 100 d at four O sub(2) levels. The O sub(2) levels were accomplished by bubbling N sub(2) containing 0, 0.2, 2.0, and 20.0% O sub(2) through the stirred suspensions.
AN: 2880922
872 of 1521
TI: Protecting tropical and subtropical coastal waters: A resource for future generations.
AU: Arrhenius,-E.
AF: Natl. Resour. Manage. Inst. Frescati Backe, Stockholm Univ., S-106 91 Stockholm, Sweden
CO: Royal Colloquium on Environment Development and Industry, Solna (Sweden), 12-14 Aug 1992
SO: AMBIO. 1992. vol. 21, no. 7, pp. 488-490
LA: English
AB: The scope of the colloquium was to cover the disruptive effects on marine-food-producing ecosystems caused by the use of water as a transport medium for organic waste as a transport medium for organic waste, living micro-organisms, and nutrient supporting growth of living organisms, emanating mainly from households in urban areas, and from agricultural activities.
AN: 2880386
873 of 1521
TI: Sulfur pool sizes and stable isotope ratios in Humex peat before and immediately after the onset of acidification.
AU: Morgan,-M.D.
AF: Dep. Biol., Rutgers Univ., Camden, NJ 08102, USA
SO: ENVIRON.-INT. Gjessing,-E.T.;Petersen,-R.C.,Jr.-eds. 1992. vol. 18, no. 6, pp. 545-553
NT: Spec. Iss.: Huemor Humex: Exp. acidification, catchment, humic lakes.
LA: English
ER: F (Freshwater)
AB: Total nonsulfate sulfur (TS), reduced inorganic sulfur (RIS), ester sulfate (ES) and carbon bonded sulfur (CBS) pool sizes, and TS and RIS stable sulfur isotopes were examined in peat cores from control and experimental sites within the Skjervatjern catchment before and 8.5 months after the onset of acidification. The total amount of excess sulfate added to the catchment up to this point was less than expected due to mechanical problems. There have been no observable effects on sulfur cycling within the peat soils. The results from this study, however, provide insight into the natural factors controlling sulfur cycling in this system and suggest that dissimilatory sulfate reduction plays a key role.
AN: 2878595
874 of 1521
TI: Cycle of halocarbons in the air-water phase.
AU: Yamasaki,-T.; Oki,-N.; Okuno,-T.
AF: Hyogo Prefectural Inst. Environ. Sci., 3-1-27 Yukihira-cho, Suma-ku, Kobe 654, Japan
CO: 1. IAWPRC Int. Symp., Otsu City (Japan), 25-28 Nov 1991
SO: HAZARD-ASSESSMENT-AND-CONTROL-OF-ENVIRONMENTAL-CONTAMINANTS-IN-WATER. Matsui,-S.-ed. 1992. vol. 25, no. 11 pp. 33-39
ST: WATER-SCI.-TECHNOL. vol. 25, no. 11
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Halocarbons are widely distributed in environment: atmosphere, hydrosphere, lithosphere and biosphere. This report presents the data on the cycle of halocarbons in air-water phase. Low-boiling-point halocarbons were monitored and about 10 kind of substances which include chlorofluorocarbon (CFC) were detected in the environment. The concentrations of halocarbons in air are influenced by weather conditions, especially by wind speed. Three CFCs, CFC-11, CFC-12 and CFC-113, were detected at the level of 0.18-1.70 ppb on the day (wind speed 0-1 m/sec), and 0.05-0.40 ppb (5-10 m/sec). Other halomethanes, chloroform and carbon tetrachloride, were detected at the level of 0.06-0.72 ppb and 0.03-0.06 ppb; a haloethane, 1,1,1-trichloroethane, was 0.50-5.3 ppb and 0.12-0.95 ppb; and haloethylenes, trichloroethylene and tetrachloroethylene were 0.02-4.1 ppb and 0.01-1.8 ppb on days of wind speed below 1 m/sec and 5-10 m/sec, respectively. Substances found in air were also detected in water phase. Concentrations of above-mentioned halocarbons in water were at the level of 0.001-0.0095 ppb in river water, 0.002-0.06 ppb in ground water, 0.001-0.036 ppb in seawater, and 0.001-0.53 ppb in rain water. In comparison with concentration of halocarbons of environmental measurement and estimation value by using the predictive fate model of chemical substances, haloethanes and haloethylenes in air exceeded the value of estimation. On the other hand, halomethanes in air almost agreed with its value, and in water phase were quite similar to the estimation.
AN: 2871242
875 of 1521
TI: The Ecology of Mangrove and Related Ecosystems.
AU: Jaccarini,-V.; Martens,-E.-(eds.)
CO: The Ecology of Mangrove and Related Ecosystems, Mombasa (Kenya), 24-30 Sep 1990
SO: HYDROBIOLOGIA. 1992. vol. 247, no. 1-3, 266 pp
LA: English
ER: M (Marine); B (Brackish)
AB: The international symposium on The Ecology of Mangrove and Related Ecosystems, Mombasa, Kenya, 24-30 September, 1990, was organized by the Department of Zoology, University of Nairobi, in collaboration with the Kenya Marine and Fisheries Research Institute, and the Regional Dispatch Centre of the Regional Cooperation in Scientific Information Exchange in the West Indian Ocean, Mombasa, Kenya. Scientific investigation of the mangrove ecosystems came from all the main tropical marine areas of the globe, representing twenty-three countries, in West and Eastern Africa, South and Southeast Asia, Central and South America, and Australia. The thirty papers published in this volume were selected from seventy presented at the symposium. It is recognized that the mangroves have intimate and complex linkages with other coastal systems, notably seagrass beds and coral reefs. So, starting from the mangrove forest and its users at the interface between the terrestrial, freshwater and marine environments, the papers presented proceed to the fully submerged seagrasses and further out to the corals. The nature of the coupling between the different systems was touched on at the symposium, but stands out as a serious gap in our knowledge. Next, chemical and physical processes which constitute the mechanisms of linkage received attention. Human uses and abuses of the ecosystems formed the last major topic of the symposium.
AN: 2870705
876 of 1521
TI: (Experimental study on the transfer of plasmid genes between enterobacteria in the marine environment.).
OT: Etude experimentale du transfert de genes plasmidiques entre les enterobacteries dans l'environnement marin
AU: Gauthier,-M.J.
AF: INSERM, Unite 303 "Mer et Sante," 1 Ave. Jean-Lorrain, 06300 Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-ON-RESEARCH-PROJECTS-1989-1991. CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K.-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-1989-1991. UNEP-Mediterranean-Action-Plan,-Athens-Greece;WHO,-Geneva-Switzerland ATHENS-GREECE UNEP 1992. pp. 61-76
ST: MAP-TECH.-REP.-SER.
LA: French
ER: M (Marine)
AN: 2868421
877 of 1521
TI: (Experimental study on the transfer of plasmid genes between enterobacteria in seawater, sediments and the digestive tracts of marine invertebrates.).
OT: Etude experimentale du transfert de genes plasmidiques entre enterobacteries dans l'eau de mer, les sediments et le tractus digestif des invertebres marins
AU: Gauthier,-M.J.; Martin,-Y.; Torregrossa,-V.
AF: INSERM Unite 303 "Mer et Sante," 1 Ave. Jean-Lorrain, 06300 Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-ON-RESEARCH-PROJECTS-1989-1991. CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K.-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-1989-1991. UNEP-Mediterranean-Action-Plan,-Athens-Greece;WHO,-Geneva-Switzerland ATHENS-GREECE UNEP 1992. no. 63 pp. 29-60
ST: MAP-TECH.-REP.-SER. no. 63
LA: French
ER: M (Marine)
AN: 2868390
878 of 1521
TI: (The influence of osmoregulation mechanisms on the survival and adaptation of enteric bacteria in the marine environment.).
OT: Influence des mecanismes d'osmoregulation sur la survie et l'adaptation des bacteries enteriques dans l'environnement marin
AU: Gauthier,-M.J.
AF: INSERM Unite 303 "Mer et Sante," 1 Ave. Jean-Lorrain, 06300 Nice, France
SO: BIOGEOCHEMICAL-CYCLES-OF-SPECIFIC-POLLUTANTS-ACTIVITY-K.-SURVIVAL-OF-PATHOGENS.-FINAL-REPORTS-ON-RESEARCH-PROJECTS-1989-1991. CYCLES-BIOGEOCHIMIQUES-DE-POLLUANTS-SPECIFIQUES-ACTIVITE-K.-SURVIE-DES-PATHOGENES.-RAPPORTS-FINAUX-SUR-LES-PROJETS-DE-RECHERCHE-1989-1991. UNEP-Mediterranean-Action-Plan,-Athens-Greece;WHO,-Geneva-Switzerland ATHENS-GREECE UNEP 1992. pp. 17-28
ST: MAP-TECH.-REP.-SER.
LA: French
ER: M (Marine)
AN: 2868349
879 of 1521
TI: Seasonal variability in primary production and particle flux in the northwestern Sargasso Sea: U.S. JGOFS Bermuda Atlantic Time-Series Study.
AU: Lohrenz,-S.E.; Knauer,-G.A.; Asper,-V.L.; Tuel,-M.; Michaels,-A.F.; Knap,-A.H.
AF: Univ. Southern Mississippi, Cent. Mar. Sci., Stennis Space Cent., MS 39529, USA
SO: DEEP-SEA-RES. 1992. vol. 39, no. 7-8A, pp. 1373-1391
LA: English
ER: M (Marine)
AB: The relationship between primary production and sediment trap-derived downward flux of particulate organic matter was characterized over a 2 year period at the U.S. JGOFS Bermuda Atlantic Time-series Study (BATS) site to evaluate the importance of temporal variations in upper ocean biogeochemical processes. Water column-integrated primary production ( integral of PP), determined once each cruise using super(14)C incubations (in situ dawn-to-dusk), peaked in late winter/early spring of both 1989 and 1990. Smaller increases in integral of PP also occurred in July 1989 and October-December 1990. Annual integral of PP was 9.2 mol C m super(-2)/y in 1989 and 12 mol C m super(-2)/y in 1990. This was higher than the 1959-1963 annual average (6.8 mol C m super(-2)/y) determined at Station "S" located approximately 50 km northwest of the BATS site.
AN: 2865866
880 of 1521
TI: Trace elements in lacustrine sediments.
OT: Elementi in traccia e sedimenti lacustri
AU: Baudo,-R.; Ferrari,-A.
SO: DIRECTOR'-S-REPORT-ON-THE-SCIENTIFIC-ACTIVITY-OF-THE-INSTITUTE-FOR-YEAR-1988. RELAZIONE-DEL-DIRETTORE-SULL'-ATTIVITA-SCIENTIFICA-DELL'-ISTITUTO-NELL'-ANNO-1988. Bernardi,-R.-de-ed. Istituto-Italiano-di-Idrobiologia,-Verbania-Pallanza-Italy no. 26 no. 1990, pp. 54-56
ST: DOC.-IST.-ITAL.-IDROBIOL. no. 26
LA: Italian
ER: F (Freshwater)
AB: Sediments from several Italian lakes have been sampled with the objective of relating their chemical composition to the geochemistry of the respective drainage basins and eventually spotting possible modifications of the biogeochemical cycles due to human activities. In 1988, the study was extended to Lake Garda and Lake Vegoritis, Greece. For each lake, several grab samples were collected to carefully depict the spatial distribution in recent sediments, and additional cores were taken for describing the temporal variations of element sedimentation. In total, almost 200 samples of sediments were obtained which after processing (drying, sieving, milling and dissolution), are to be analyzed for P, Zn, Ni, Mn, Fe, Cr, V, Cu, Ti, C, N, Pb, Cd, Hg, As, and possibly for other elements (Na, K, Ca, Mg, Co, Mo, Sb, Tl, and so on), by means of atomic absorption, X-ray fluorescence and nuclear activation analysis.
AN: 2862176
881 of 1521
TI: Suspended matter in Luoyuan Bay seawater, Fujian.
AU: Guo,-Laodong; Hong,-Huasheng
AF: Xiamen Univ., Xiamen 361005, People's Rep. China
SO: OCEANOL.-LIMNOL.-SIN.-HAIYANG-YU-HUZHAO. 1992. vol. 23, no. 1, pp. 83-89
LA: Chinese
ER: M (Marine)
AB: Distributions and features of total suspended matter (TSM) in Luoyuan Bay seawater were studied during six cruises from November 1986 to September 1987. It was found that resuspension of sediments takes an important role in controlling the distribution of TSM in winter. However, the distribution of TSM in summer depends on biological processes and river inputs. The chemical compositions of the particles also showed seasonal variations. The correlation between TSM and particulate organic carbon (POC) showed that the content of POC was related to biological activities when the primary production was enhanced from May to September, whereas the content of POC was controlled by the terrestrial input as the primary production was low from November to March. Increment of TSM caused by resuspension can result in the decline of transparency and further affects the level of primary production of the bay. But, it can also increase the availability of nutrients by releasing them from the resuspended particles. The ratio of POC flux to the primary production is about 67-85% in summer estimated from the sediment traps. POC from the primary producers settling to the sediments can play an important role in the detritus foodchain in Luoyuan Bay seawater.
AN: 2861458
882 of 1521
TI: Ecology of sea ice biota. 2. Global significance.
AU: Legendre,-L.; Ackley,-S.F.; Dieckmann,-G.S.; Gulliksen,-B.; Horner,-R.; Hoshiai,-T.; Melnikov,-I.A.; Reeburgh,-W.S.; Spindler,-M.; Sullivan,-C.W.
AF: Dep. Biol., Univ. Laval, Quebec, PQ G1K 7P4, Canada
SO: POLAR-BIOL. 1992. vol. 12, no. 3-4, pp. 429-444
NT: Bibliogr.: 175 ref.
LA: English
ER: M (Marine)
AB: In this paper, new estimates of Arctic and Antarctic production of biogenic carbon are derived, and differences as well as similarities between the two oceans are examined. In ice-covered seas, high algal concentrations (blooms) occur in association with several types of conditions. Blooms often lead to high sedimentation of intact cells and faecal pellets. In addition to ice-related blooms, there is progressive accumulation of organic matter in Arctic multi-year ice, whose fate may potentially be similar to that of blooms. A fraction of the carbon fixed by microalgae that grow in sea ice or in relation to it is exported out of the production zone. This includes particulate material sinking out of the euphotic zone, and also material passed on to the food web. Pathways through which ice algal production does reach various components of the pelagic and benthic food webs, and through them such top predators as marine mammals and birds, are discussed.
AN: 2859334
883 of 1521
TI: Protist abundance and carbon concentration during a Phaeocystis -dominated bloom at an Antarctic coastal site.
AU: Davidson,-A.T.; Marchant,-H.J.
AF: Australian Antarctic Div., Channel Highw., Kingston, Tas. 7050, Australia
SO: POLAR-BIOL. 1992. vol. 12, no. 3-4, pp. 387-395
NT: Bibliogr.: 60 ref.
LA: English
ER: M (Marine)
AB: Changes in the concentrations of bacteria, phytoplankton, protozoa, dissolved organic carbon (DOC) particulate organic carbon (POC), particulate carbohydrate (PCHO) and particulate organic nitrogen (PON) were followed throughout the summer at an Antarctic coastal site. The colonial prymnesiophyte Phaeocystis pouchetii was the first major phytoplankton species to bloom, reaching concentrations of 6 x 10 super(7) cells/l and remained numerically dominant for most of the summer. During the P. pouchetii) bloom the concentration of most other autotrophs did not increase. Microheterotroph abundance peaked during or immediately after the Phaeocystis bloom. Their peak coincided with very high concentrations of organic carbon, particularly DOC which exceeded 100 mg/l, and low bacterial abundance. Maximum bacterial abundance was reached after the decline in microheterotroph numbers.
AN: 2859254
884 of 1521
TI: Dynamics of nutrients and phytoplankton, and fluxes of carbon, nitrogen and silicon in the Antarctic Ocean.
AU: Treguer,-P.; Jacques,-G.
AF: Inst. Etudes Mar., URA CNRS 1513, 6 Ave. Le Gorgeu, F-29287 Brest-Cedex, France
SO: POLAR-BIOL. 1992. vol. 12, no. 2, pp. 149-162
NT: Bibliogr.: 124 ref.
LA: English
ER: M (Marine)
AB: Four major functional units have been identified in the Southern Ocean and the mechanisms that control the dynamics of nutrients and phytoplankton are detailed for the different sub-systems. The very productive Coastal and Continental Shelf Zone (CCSZ, 0.9 M km super(2)) can experience severe macronutrient depletion paralleling intense diatom-dominated phytoplankton blooming (maximum > 8 mg Chl a m super(-3)) at the ice edge. In the Seasonal Ice Zone (SIZ, 16 M km super(2)), dramatic variations in the hydrological structure occur in surface waters during the spring to summer retreat of the pack-ice, changing from a well-mixed system to a stratified one within the reaches of the ice edge. Grazing activity of euphausiids limits phytoplankton biomass to a moderate level (Chl a maximum around 4 mg m super(-3)).
AN: 2859201
885 of 1521
TI: Stable carbon isotope composition, depth distribution and fate of macroalgae from the Antarctic Peninsula region.
AU: Fischer,-G.; Wiencke,-C.
AF: Fachber. Geowiss., Univ. Bremen, Klagenfurter Str., D-W 2800 Bremen, FRG
SO: POLAR-BIOL. 1992. vol. 12, no. 3-4, pp. 341-348
NT: Bibliogr.: 47 ref.
LA: English
ER: M (Marine)
AB: Stable carbon isotope composition of macroalgae collected at King George Island (Antarctica) ranged from about -8 ppt to -34 ppt. We hypothesize that the delta super(13)C values are related to the depth distribution species inhabiting greater depth had much lower values (around -30 ppt) compared to species from shallower waters (around -17 ppt). Isotopic studies on sediment trap samples from the King George Basin (2,000 m deep) revealed that benthic macroalgae contributed strongly to the total organic carbon pool of the deeper basin waters during austral spring and summer. Fragments of brown macroalgae (Desmarestiales) were detected in microscopical analyses of semi-thin sections of sediment samples from the Bransfield Strait. Possible mechanisms regarding the erosion of benthic macroalgae and their transport to the deeper water and to the sediment are summarized.
AN: 2859169
886 of 1521
TI: Bacterial transfer of methane and detritus; implications for the pelagic carbon budget and gaseous release.
AU: Hessen,-D.; Nygaard,-K.
AF: Norwegian Inst. Water Res., P.O. Box 69, Korsvoll, N-0808 Oslo 8, Norway
CO: 5. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Environments, Helsingoer (Denmark), 18-23 Aug 1991
SO: MICROBIAL-ECOLOGY-OF-PELAGIC-ENVIRONMENTS. Bjoernsen,-P.K.;Riemann,-B.-eds. STUTTGART-FGR SCHWEIZERBART'-SCHE-VERLAGSBUCHHANDLUNG 1992. no. 37 pp. 139-148
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 37
LA: English
AB: Phytoplankton exudate release is generally considered the most important source of carbon for pelagic bacteria in aquatic communities, but in many localities allochthonous inputs may be the main source of carbon. In a well studied humic lake, detrital compounds fueled more than 80% of bacterial secondary production. The lake also supported a vigorous methane production. Methane was oxidized over the entire water column above the anaerobic layer, and preliminary data suggest that carbon fixed by methanotrophs may be in the same order of magnitude as bacterial secondary production. Thus the utilization of detritus and oxidation of methane may be important sources of carbon for bacteria and thus serve as "new" inputs of carbon to pelagic food webs. Such allochthonously influenced lakes may also be important gas conduits to the atmosphere due to oxidation of organic compounds and methane.
AN: 2858606
887 of 1521
TI: Large lakes and their sustainable development.
AU: Tilzer,-M.M.; Bossard,-P.
AF: Limnol. Inst., Univ. Konstanz, Mainaust. 212, D-7750 Konstanz, FRG
SO: AQUAT.-SCI. 1992. vol. 54, no. 2, pp. 91-103
LA: English
ER: F (Freshwater)
AB: This contribution has been edited from a working document, prepared by invited scientists attending a workshop in Konstanz, Germany, on the importance of external perturbations for short- and long-term changes in large lakes ecosystems, held from 21 to 26 October, 1991. It tries to assess our current understanding of the most important processes involved in the functioning of large lakes and to identify the currently most urgent research priorities in the fields of land-water interactions, physical processes, biogeochemistry and nutrient relations, remote sensing, biological interactions in food webs, and long-term monitoring programs.
AN: 2857149
888 of 1521
TI: Using parallel salinity and temperature profiles for calculations of estuarine fluxes with reference to the Baltic proper.
AU: Rahm,-L.; Wulff,-F.
AF: Dep. Water and Environ. Stud., Linkoeping Univ., S-581 83 Linkoeping, Sweden
SO: NETH.-J.-SEA-RES. 1992. vol. 29, no. 4, pp. 281-289
LA: English
ER: M (Marine)
AB: A diagnostic advection-diffusion equation system in a "natural coordinate" frame of reference is investigated in order to improve its robustness. The dependence of the leading-order solutions on higher-order features of the hydrographic data has been decreased and a differential equation with an analytical solution is obtained. The properties of the lowest-order equation are compared with previous studies where the undegenerated equations were used to estimate the distribution of both the diapycnal salt flux and the oxygen consumption within the Baltic proper. The agreement found is within the acceptable bounds. Finally a pilot study of a silicate budget of the Baltic proper has been performed.
AN: 2856920
889 of 1521
TI: Nitrogen dynamics at the VERTEX time-series site.
AU: Harrison,-W.G.; Harris,-L.R.; Karl,-D.M.; Knauer,-G.A.; Readlje,-D.G.
AF: Biol. Oceanogr. Div., Dep. Fish. and Oceans, Bedford Inst. Oceanogr., Box 1006, Dartmouth, NS B2Y 4A2, Canada
SO: DEEP-SEA-RES. 1992. vol. 39, no. 9A, pp. 1535-1552
LA: English
ER: M (Marine)
AB: Euphotic zone concentrations and fluxes of nitrate, ammonium, particulate and dissolved organic nitrogen were measured over an 18 month period at the VERTEX time-series site in the oligotrophic northeast Pacific (33 degree N, 139 degree W). Variations in all N-forms were significant but not clearly linked to the temporal hydrographic cycle. Inorganic-N-uptake (nitrate + ammonium) from super(15)N tracer experiments generally paralleled primary productivity variations, peaking in summer; ammonium accounted for most of the uptake ( similar to 90%) and temporal variability. Comparisons of super(15)N results with estimates of autotrophic N-uptake from super(14)C incorporation into protein suggest that as much as 40% of the annual inorganic-N uptake was due to microheterotrophs; peak heterotrophic N-uptake occurred in summer when heterotrophic biomass was at its maximum. Nitrate uptake (new production) was less variable than ammonium uptake and annually equivalent to particulate nitrogen export from sediment traps. Dissolved organic-N (DON) represented the largest and most variable N-pool, accounting for 80-90% of the total nitrogen in the euphotic zone.
AN: 2856628
890 of 1521
TI: The carbon balance during the 1989 spring bloom in the North Atlantic Ocean, 47 degree N, 20 degree W.
AU: Bender,-M.; Ducklow,-H.; Kiddon,-J.; Marra,-J.; Martin,-J.
AF: Grad. Sch. Oceanogr., Univ. Rhode Island, Kingston, RI 02881, USA
SO: DEEP-SEA-RES. 1992. vol. 39, no. 10A, pp. 1707-1725
LA: English
ER: M (Marine)
AB: The authors report on studies of the carbon balance of the upper water column, done as part of the JGOFS North Atlantic Bloom Experiment, over a 13-day period, at 47 degree N, 20 degree W, during the 1989 spring phytoplankton bloom. Gross carbon production was calculated from data on super(18)O gross O sub(2) production and from super(14)C production as well. Net carbon production was calculated from net O sub(2) production rates measured in vitro, as well as from changes in the inventories of nutrients and O sub(2) along with O sub(2) evasion rates by gas exchange. Gross carbon production during this period was measured to be 1.83 mol m super(-2), and net production was 0.68 mol m super(-2). Of this net carbon production, 0.30 mol m super(-2) was stored in the euphotic zone as particulate organic carbon, and 0.09 mol m super(-2) rained out to depths > 150 m. The remainder was remineralized to DIC in the 50-150 m depth interval, with perhaps some DOC storage in the upper 150 m.
AN: 2854524
891 of 1521
TI: Influence of carbon availability on denitrification in the central Baltic Sea.
AU: Brettar,-I.; Rheinheimer,-G.
AF: NIWAR, Water Qual. Cent., P.O. Box 11-115, Hamilton, New Zealand
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 6, pp. 1146-1163
LA: English
ER: M (Marine)
AB: Denitrification was investigated in the Baltic proper at two stations with different conditions in the deep water. The Gotland Deep was examined as an example of a basin with anoxic, H sub(2)S-containing deep water and station T was taken as an example of low-oxygen (< 0.2 ml/liter). sulfide-free deep water. Denitrification was measured by the acetylene blockage method; in addition, N sub(2)O reduction was followed in samples without acetylene. To shed light on the factors limiting denitrification, we compared in situ rates to denitrification after adding nitrate or electron donors. Denitrification was restricted to the layer of the oxic-anoxic interface in the Gotland Deep and to the water layer near the sediment of station T. For both stations it could be shown that denitrification was not limited by nitrate availability. A lack of available organic C seemed to limit denitrification rates and growth of denitrifiers. As a result of limitation in the water column, denitrification was restricted to energy-rich interfaces.
AN: 2854359
892 of 1521
TI: The phosphorus cycle in coastal marine sediments.
AU: Sundby,-B.; Gobeil,-C.; Silverberg,-N.; Mucci,-A.
AF: Univ. Quebec, INRS-Oceanol., Cent. Oceanogr. Rimouski, 310 Allee des Ursulines, Rimouski, PQ G5L 3A1, Canada
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 6, pp. 1129-1145
LA: English
ER: M (Marine); B (Brackish)
AB: Approximately half of the sedimentation flux of particulate phosphorus in the Laurentian Trough in The Gulf of St. Lawrence is mobilized within the sediment and returned to the water column. In the oxidizing surface sediment, a major portion of the sedimentation flux of organic phosphorus is mineralized, and the released phosphate is partitioned between the pore water and surface adsorption sites. Surface-adsorbed phosphate is released to the pore water as needed to replace dissolved phosphate that escapes to the overlying water. Most of the phosphate is released deeper in the sediment column from iron oxides undergoing reduction. The nonmobilized phosphorus, which is buried with the accumulating sediment, appears to consist mostly of stable minerals such as apatite. The concentration of dissolved phosphate in sediment pore waters increases sharply across the sediment-water interface from 2 mu mol PO sub(4) liter super(-1) in the bottom water to 6 plus or minus 3 mu mol PO sub(4) liter super(-1) in the top centimeter, remains almost constant at this value down to 5-15 depth, and then increases rapidly with further depth.
AN: 2854338
893 of 1521
TI: Role of benthos in the migration of microelements in Zaporozhye Reservoir.
AU: Varenko,-N.I.; Zagubizhenki,-N.I.; Gaydash,-Yu.K.
AF: Inst. Biol., Dnepropetrovsk Univ., Ukraine
SO: HYDROBIOL.-J. 1991. vol. 27, no. 3, pp. 90-95
LA: English
ER: F (Freshwater)
AB: Benthic organisms of Zaporozhye Reservoir, Ukraine, differ in their ability to accumulate microelements; the influencing factors are species, season of the year, and the concentrations of the microelements in the abiotic components of the ecosystem. The concentration of the metals by the benthos are, respectively, 200-7,000 for manganese, 900-11,000 for zinc, 300-5,000 for copper, 250-5,800 for lead, and 150-1,100 for cobalt. Organisms that concentrate particular elements are identified. The roles of certain species of benthos in the biological migration of metals in the abiotic components of the reservoir's ecosystem have been identified. The largest amounts are set into circulation by the mollusks.
AN: 2853462
894 of 1521
TI: Biogeochemical cycles of specific pollutants (activity K). Final report on project on survival of pathogenic organisms in seawater.
CA: UNEP Mediterranean Action Plan, Athens (Greece)
WHO, Geneva (Switzerland)
SO: MAP-TECH.-REP.-SER. ATHENS-GREECE UNEP 1991. no. 55, 96 pp
NT: Title also in Fr.
LA: English
ER: M (Marine)
AB: Microorganisms in sewage are dispersed by turbulent diffusion when discharged into the sea. Physiological damage may be sublethal or cause death of the cell. This damage or stress can be studied by observing either the bacterial structural disorganization or their inability to carry out a determined metabolic function in a selective medium. However, these stress cells can be developed in culture media which do not contain inhibitory substances. The importance of the study of the physiological damage to pathogenic cells is based on the non-detection of these cells in the performance of standard microbiological tests, which are based on the examination of selective culture media. A large variety of environmental conditions or factors exist which can kill, damage or simply cause the disappearance of microorganisms from the environment. These include physical, chemical and biological processes.
AN: 2853189
895 of 1521
TI: Factors controlling the concentration of particulate carbohydrates and amino acids in the Parana River.
AU: Kempe,-S.; Depetris,-P.J.
AF: Inst. Biogeochem. and Mar. Chem., Univ. Hamburg, Bundesstr. 55, D-2000 Hamburg, FRG
SO: HYDROBIOLOGIA. 1992. vol. 242, no. 3, pp. 175-183
LA: English
ER: F (Freshwater)
AB: Particulate carbohydrates and particulate amino acids were determined in a set of samples from the Parana River, Argentina, covering a stretch of over 1300 km. To gain an understanding of the factors which control the concentrations of these organic compounds, a multivariate statistical approach was used (R-mode varimax factor analysis). This technique separated the influence of various sources of organic matter. The floodplain of the middle reach (about 900 km long and 20-30 km wide) was the most significant source controlling the concentrations of particulate carbohydrates (PCH), providing angiosperm debris, phytoplankton and grasses. Particulate amino acids (PAA) concentrations were determined markedly both by contributions from the Paraguay basin, and the lotic and lentic environments of the floodplain. Sugars single out forested tributary basins as sources of bacteria while amino acids point toward the Paraguay River as a major source of biodegraded material; heterotrophic processes, however, appear more clearly depicted with PAA than with PCH. A downstream increase of the PCH/PAA ratio suggests a larger consumption of PAA in the lowermost reaches.
AN: 2850355
896 of 1521
TI: The degradation of arsenobetaine to inorganic arsenic by sedimentary microorganisms.
AU: Hanaoka,-K.; Tagawa,-S.; Kaise,-T.
AF: Dep. Food Sci. and Technol., Shimonoseki Univ. Fish., Yoshimi-cho, Shimonoseki 759-65, Japan
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: SEDIMENT-WATER-INTERACTIONS. Hart,-B.T.;Sly,-P.G.-eds. 1992. vol. 235-236 pp. 623-628
ST: HYDROBIOLOGIA. vol. 235-236
LA: English
ER: M (Marine)
AB: Two growth media containing arsenobetaine ((CH sub(3)) sub(3) As super(+)CH sub(2)COO super(-)) were mixed with coastal marine sediments, the latter providing a source of microorganisms. The mixtures were kept at 25 degree C in the dark and shaken for several weeks under an atmosphere of air. The disappearance of arsenobetaine and the appearance of two metabolites were followed by HPLC. The HPLC-retention time of the first metabolite agreed with that of trimethylarsine oxide ((CH sub(3)) sub(3)AsO). The second metabolite was identified as arsenate (As(V)) using hydride generation/cold trap/GC MS analysis and thin layer chromatography. This is the first scientific evidence showing that arsenobetaine is degraded by microorganisms to inorganic arsenic via trimethylarsine oxide. The degradation of arsenobetaine to inorganic arsenic completes the marine arsenic cycle that begins with the methylation of inorganic arsenic on the way to arsenobetaine.
AN: 2849629
897 of 1521
TI: Sulfate-reduction process in sediments of Lake Kinneret, Israel.
AU: Hadas,-O.; Pinkas,-R.
AF: Kinneret Limnol. Lab., Israel Oceanogr. and Limnol. Res., P.O. Box 345, Tiberias 14102, Israel
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: SEDIMENT-WATER-INTERACTIONS. Hart,-B.T.;Sly,-P.G.-eds. 1992. vol. 235-236 pp. 295-301
ST: HYDROBIOLOGIA. vol. 235-236
LA: English
ER: F (Freshwater)
AB: Monomictic Lake Kinneret is stratified during summer and autumn, resulting in a hypolimnion rich in H sub(2)S (3-7 mg/l). In winter and spring every year a bloom of dinoflagellate Peridinium gatunense) produces an average biomass of 150,000 ton wet weight. Part of this biomass sinks to the hypolimnion and sediments where it is decomposed and mineralized, with some of the mineralization due to the activity of sulfate-reducing bacteria (SRB). The sulfate-reduction potential of the upper sediment layer at the deepest part of the lake (42 m) was measured. The activity of the enzyme arylsulfatase was also monitored. Rates of sulfate-reduction ranged from a minimum of 12 nmoles SO sub(4)@) super(2)-r)educed cm super(-3)/day in December before lake overturn to a maximum of 1673 nmoles SO sub(4)@) super(2)-r)educed cm super(-3)/day in July during stratification. These rates are considerably higher than those recorded from other freshwater lakes in the world and are probably limited more by the availability of organic matter than by sulfate concentrations.
AN: 2848175
898 of 1521
TI: Chromium cycling in natural water systems.
AU: Johnson,-C.A.; Sigg,-L.
AF: Inst. Water Resour. and Water Pollut. Control (EAWAG), Swiss Fed. Inst. Technol. (ETH) Zuerich, CH-8600 Duebendorf, Switzerland
CO: 4. IAEAC Workshop on Toxic Metal Compounds (Interrelation between Chemistry and Biology), Les Diablerets (Switzerland), 4 Mar 1991
SO: METAL-COMPOUNDS-IN-ENVIRONMENT-AND-LIFE,-4.-INTERRELATION-BETWEEN-CHEMISTRY-AND-BIOLOGY.-IN-MEMORIUM-OF-HANS-WOLFGANG-NUERNBERG. Merian,-E.;Haerdi,-W.-eds. NORHTWOOD,-MIDDLESEX-UK SCIENCE-AND-TECHNOL.-LETTERS 1992. pp. 73-80
NT: Special Supplement to Chemical Speciation and Bioavailability.
LA: English
ER: F (Freshwater)
AB: The chromium cycle in natural waters has received much attention in recent years with an emphasis on the controlling chemical processes. The dynamics of the Cr cycle was investigated in a seasonally anoxic lake, the Greifensee in Switzerland. The results show that Cr(VI) is removed from the water column by reduction and/or adsorption. Reduced Cr(III) is present in colloidal form and is not oxidised to Cr(VI). In other systems Cr(III) oxidation can be observed.
AN: 2847675
899 of 1521
TI: Hydrodynamical singularities as controls of recycled versus export production in oceans.
AU: Legendre,-L.; Fevre,-J.-Le
AF: Dep. Biol., Univ. Laval, Laval, PQ G1K 7P4, Canada
CO: Dahlem Workshop on Productivity of the Ocean: Present and Past, Berlin (Germany), 24-29 Apr 1988
SO: PRODUCTIVITY-OF-THE-OCEAN:-PRESENT-AND-PAST.-REPORT-OF-THE-DAHLEM-WORKSHOP-ON-PRODUCTIVITY-OF-THE-OCEAN:-PRESENT-AND-PAST,-BERLIN-1988,-APRIL-24-29. Berger,-W.H.;Smetacek,-V.S.;Wefer,-G.-eds. CHICHESTER-UK WILEY-INTERSCIENCE-PUBL. 1989. no. 44 pp. 49-63
ST: LIFE-SCI.-RES.-PAP. no. 44
LA: English
ER: M (Marine)
AB: Phytoplankton production in oceans is either recycled in the euphotic zone or exported to the remainder of the ecosystem. The fate of marine primary production is discussed within the framework of a conceptual model, which specifies 5 major bifurcations where part of the production may be channeled into export pathways: production of large versus small cells; sinking or not of large cells; grazing versus accumulation (and microphagy) of large cells; recycling of small cells in the microbial food loop or aggregation; and sinking versus accumulation (and microphagy) of aggregates. It is shown that hydrodynamical singularities play a major role at each bifurcation in favoring production export over in situ recycling, which influences both present marine ecosystems and geological records.
AN: 2846036
900 of 1521
TI: Management of the riparian zone to maximize accumulation of large woody debris in streams.
AU: Rabon,-M.W.; Weyrick,-R.
AF: Univ. New Hampshire, Durham, NH, USA
CO: 2. Joint Meet. of the Maine Div. of New England Soc. of American Foresters, Maine Chapter of the Wildlife Soc., and the Atlantic Int. Chapter of the American Fisheries Soc., Portland, ME (USA), 15-17 Mar 1989
SO: FOREST-AND-WILDLIFE-MANAGEMENT-IN-NEW-ENGLAND-WHAT-CAN-WE-AFFORD?. PORTLAND,-ME-USA UNIV.-OF-MAINE-COLL.-OF-FOREST-RESOURCES 1989. no. 36 pp. 183-189
ST: MISC.-REP.-ME.-AGRIC.-EXP.-STN. no. 36
NT: Also as: Coll. For. Resour. CFRU Inf. Rep. No. 21. AIC 100.M28M.
RN: SAF 89-05 (8905)
LA: English
ER: F (Freshwater)
AB: In response to the U.S. Forest Service "Rise to the Future" program, the White Mountain (New Hampshire) and Green Mountain (Vermont) National Forests placed increased emphasis on fisheries management. As part of this initiative a cooperative agreement was developed with the Agricultural Experiment Station, University of New Hampshire to analyze alternative management prescriptions in appropriate riparian zones with the objective of increasing recruitment of large woody debris in streams to enhance fish habitat. The riparian zone and the role of large woody debris are discussed as well as the cooperative agreement goals and how the growth model, FIBER, will be used.
AN: 2841450
901 of 1521
TI: Modeling phosphorus cycling in a well-mixed coastal plain estuary.
AU: Lebo,-M.E.; Sharp,-J.H.
AF: Div. Environ. Stud., Univ. California, Davis, CA 95616, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1992. vol. 35, no. 3, pp. 235-252
LA: English
ER: M (Marine); B (Brackish)
AB: Phosphorus cycling in the Delaware Estuary was examined using numerical methods to calculate fluxes and estimate net regeneration. In the tidal river, the flux of total phosphorus (TP) increased threefold compared to Delaware River due to municipal inputs, with most of TP flux as dissolved inorganic phosphate (DIP, 56-59%). A mass balance for TP in the river indicated that a large fraction (44-67%) of TP inputs was retained mainly through geochemical processes. Phosphorus cycling in Delaware Bay, in contrast, was dominated by biological uptake and recycling. Within the bay, DIP input from the tidal river was transformed into phytoplankton biomass. The biological dominance of P cycling in the bay resulted in strong seasonal variations in TP flux. Throughout the year, except during the spring, regenerated DIP was sufficient to supply 102 plus or minus 19, 94 plus or minus 10, and 95 plus or minus 6% of phytoplankton P-demand in the upper, middle, and lower bay respectively. During the spring, there was an imbalance between uptake and regeneration resulting in DIP depletion. 71-97% of apparent regeneration occurred within the water column, with sediment DIP release contributing an additional 3-25%. On an annual basis, 84% of TP entering the salinity gradient of the estuary was exported to coastal waters.
AN: 2841131
902 of 1521
TI: Structural and behavioral characteristics of a commercial humic acid and natural dissolved aquatic organic matter.
AU: Grasso,-D.; Chin,-Y.-P.; Weber,-W.J.,Jr.
AF: Dep. Civil Eng., Univ. Connecticut, Storrs, CT 06269-3037, USA
SO: CHEMOSPHERE. 1990. vol. 21, no. 10-11, pp. 1181-1197
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Dissolved organic matter (DOM) from two natural surface water sources and a commercial humic acid were analyzed using gel-permeation chromatography, high pressure reverse phase liquid chromatography, and super(1)H-NMR spectroscopy. Results from the chromatographic studies show that the DOM of two natural waters consisted primarily of relatively low molecular weight, polar organic constituents, while large and relatively nonpolar macromolecules comprised a significant fraction of the commercial humic acid. Based upon these composite results of the several different types of analysis employed, it is evident that the humic acid examined, and possibly others prepared in the same way, contain molecular structures which exhibit physical and chemical properties that do not reflect the true nature of DOM in real aquatic systems.
AN: 2838869
903 of 1521
TI: US Joint Global Ocean Flux Study program.
SO: OCEANUS. 1992. vol. 35, no. 1, pp. 57-59
NT: Spec. iss.: Marine Chemistry.
LA: English
ER: M (Marine)
AB: The ocean's role in the global carbon cycle has attracted the interest of scientists from diverse disciplines for more than half a century, an interest sharpened in recent years by concerns about the effects of human activity upon atmospheric levels of carbon dioxide (CO sub(2)) and other greenhouse gases. The Joint Global Ocean Flux Study (JGOFS) builds on accumulated knowledge about the ocean's chemical, biological, and physical processes to increase understanding of the ocean carbon cycle. The program has two primary goals: to determine at a global level the processes that control the movement of carbon and other biologically active elements in the ocean and the way this cycling interacts with the atmosphere, the ocean margins, and the seafloor; and to improve our ability to make global-scale predictions of the likely response of ocean processes to changes in climate associated with human activities.
AN: 2837593
904 of 1521
TI: Biogeochemical processes on the seafloor.
AU: Sayles,-F.L.
SO: OCEANUS. 1992. vol. 35, no. 1, pp. 68-75
NT: Spec. Iss.: Marine Chemistry.
LA: English
ER: M (Marine)
AB: The deep-ocean seafloor is an integral part of the ocean-atmosphere system. Processes occurring at and near the sediment-water interface can strongly influence chemical concentrations in the surface ocean (especially nutrients essential to primary production), the composition of the atmosphere (particularly its carbon dioxide content), and the record of past climate that is preserved in the sediments themselves. The importance of seafloor processes to our understanding of the ocean and the way chemicals cycle through it, past and present, has fostered many studies of this region, accounting for some 70 percent of the solid earth's surface. These investigations have detailed the origin, nature, and rate of material delivery to many areas of the seafloor. In addition, we have learned much about the reactions occurring on the seafloor and the profound influence they have on the fate of all materials delivered to this critical interface.
AN: 2837580
905 of 1521
TI: Introduction: Marine chemistry.
AU: Farrington,-J.W.
SO: OCEANUS. 1992. vol. 35, no. 1, pp. 11-17
NT: Spec. Iss.: Marine Chemistry.
LA: English
ER: M (Marine)
AB: The oceans are a complex chemical soup. Marine chemists apply a variety of sophisticated instruments to defining the soup's chemical composition and the processes that control it, and to unravelling the biochemistry of the organisms that live in it. Their research advances general knowledge of the oceans and of chemistry, and frequently has immediate, profound implications for wise stewardship of local, regional, and global habitats.
AN: 2837549
906 of 1521
TI: Balancing the budget: Carbon dioxide sources and sinks, and the effects of industry.
AU: Takahashi,-T.; Tans,-P.P.; Fung,-I.
SO: OCEANUS. 1992. vol. 35, no. 1, pp. 18-28
NT: Spec. Iss.: Marine Chemistry.
LA: English
ER: M (Marine)
AB: Molecules of carbon dioxide (CO sub(2)) and other trace gases absorb infrared radiation or heat. An atmospheric increase in these infrared-absorbing gases, which include water vapor, methane, and chlorofluorocarbon (the Freons or CFCs) would permit less heat to escape from Earth's surface into space. The atmosphere would retain more heat, in the way a greenhouse holds heat, and this "greenhouse effect" may be accompanied by some dire consequences: Regional desertification, dramatic sea-level rise, and an increase in both the frequency and intensity of hurricanes have been predicted. Greenhouse gases are measured regularly (from hourly to monthly, depending upon the intended purpose) all over the world, and chemical analyses of air bubbles trapped in old glacial ice provide pre-industrial concentrations. These measurements show that the atmospheric carbon dioxide concentration has increased by 25 percent since the pre-industrial period (1750 to 1800), from about 280 parts per million then to 350 parts per million by volume today. The concentration of methane has nearly doubled, from about 800 to 1,700 parts per billion since the pre-industrial time. The CFCs have gone from zero, prior to 1950, to about 600 parts per trillion today. Many observations support the notion that greenhouse warming is already occurring.
AN: 2837541
907 of 1521
TI: Sulphate-reduction and sulpho-oxidation at Cadiz Bay (S.W. Spain).
AU: Blasco,-J.; Gomez-Parra,-A.; Forja,-J.; Establier,-R.
AF: Inst. Cienc. Mar. de Andalucia, Poligono Rio San Pedro s/n, 11510 Puerto Real, Cadiz, Spain
SO: REV.-INT.-OCEANOGR.-MED. 1992. vol. 105-106, pp. 4-18
LA: English
ER: M (Marine)
AB: Sulphate reduction and sulpho-oxidation have been enzymatically determined in water and sediment from Cadiz Bay. The study has been performed during 1983-1984 in 12 sampling stations. They were selected taking into account both granulometry of the sediment and the different degree of influence of urban and industrial wastes. A significant positive correlation between sulphate reduction and sulpho-oxidation rates in sediments has been established, whereas only a relative seasonal evolution of sulpho-oxidation in the water column was found.
AN: 2835348
908 of 1521
TI: (Chemistry of aquatic environments. Chemistry of natural waters and interfaces in the environment.).
OT: Chimie des milieux aquatiques. Chimie des eau naturelles et des interfaces dans l'environnement
AU: Sigg,-L.; Stumm,-W.; Behra,-P.
AF: Ec. Polytech. Fed. Zurich (ETH, EAWAG)
SO: PARIS-FRANCE MASSON 1992. 391 pp
LA: French
ER: F (Freshwater)
AB: Chemistry of natural waters is a main bond between the great geochemical cycles and life on the planet. This chemistry, which reflects the mineral composition of the globe and the biochemical needs of the forms of life, is a central interest for environmental sciences. This book has been written for students and scientists studying waters--water cycles, water processes, water pollution, and air-water interaction--and for a class for the teaching of environmental chemistry and water chemistry, technology, geochemistry, and hydrobiology.
AN: 2835164
909 of 1521
TI: Geochemistry and loading history of phosphate and silicate in the Hudson Estuary.
AU: Clark,-J.F.; Simpson,-H.J.; Bopp,-R.F.; Deck,-B.
AF: Lamont-Doherty Geol. Obs., Columbia Univ., Palisades, NY 10964, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1992. vol. 34, no. 3, pp. 213-233
LA: English
ER: B (Brackish)
AB: The loading history and geochemistry of soluble reactive phosphorus (SRP) and dissolved silica (DSi) are evaluated in the Hudson estuary using 16 years of axial transect data. SRP behaves atypically in the estuary. Profiles show conservative mixing between a large mid-salinity source and the freshwater and seaward end members. Order of magnitude calculations indicate that waste water treatment facilities (WWTFs) are the dominant mid-salinity SRP source. DSi profiles display behaviour more typical of other estuaries in the northeastern United States, showing conservative mixing during periods of high flow and a midsalinity source during periods of low flow. A single layered multi-box model is used to evaluate the loading history of SRP and DSi.
AN: 2834889
910 of 1521
TI: The dynamic changes of stable isotopic ratios of carbon and nitrogen in suspended and sedimented particulate organic matter during a phytoplankton bloom.
AU: Nakatsuka,-T.; Handa,-N.; Wada,-E.; Wong,-Chi-Shing
AF: Water Res. Inst., Nagoya Univ., Chikusa-ku, Nagoya 464-01, Japan
SO: J.-MAR.-RES. 1992. vol. 50, no. 2, pp. 267-296
LA: English
ER: M (Marine)
AB: The dynamic changes of carbon and nitrogen stable isotopic ratios in suspended and sedimented particulate matter were observed together with many other chemical and biological properties during a phytoplankton bloom induced by nutrient addition in a controlled ecosystem enclosure (CEE, about 70 m super(3)) in Saanich Inlet, British Columbia, Canada. Both of the stable isotopic ratios of carbon ( delta super(13)C) and nitrogen ( delta super(15)N) in suspended particulate organic matter showed characteristic patterns of variations in surface water during the bloom. The delta super(13)C of suspended particulate matter increased with the growth of phytoplankton population and decreased gradually after the depletion of NO sub(3) super(-) and NO sub(2) super(-). The delta super(15)N of suspended particulate matter was very low soon after the beginning of phytoplankton bloom, but the value increased rapidly with the decrease in NO sub(3) super(-) and NO sub(2) super(-), and reached maximal value following nutrient depletion, after which the delta super(15)N remained high until the end of the experiment.
AN: 2833217
911 of 1521
TI: (Fate and effects of trace elements in marine organisms.).
OT: Devenir et effets des elements traces dans les organismes marins
AU: Romeo,-M.; Amiard,-J.C.
AF: INSERM, 4303 "Mer et Sante", B.P. 3, 06230 Villefranche-sur-mer, France
SO: ANALUSIS. 1992. vol. 20, no. 6, pp. M42-M44
LA: French
ER: M (Marine)
AB: By their bioaccumulation capacity and their secretion marine organisms play an important part in the biogeochemical cycles of metals in marine environment. By the possible bioaccumulation at different levels of the food chain these trace elements can be dangerous for human health.
AN: 2832627
912 of 1521
TI: Modification of the N:P ratio in lakes by in situ processes.
AU: Levine,-S.N.; Schindler,-D.W.
AF: Sch. Nat. Resour., Univ. Vermont, Burlington, VT 05405, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 5, pp. 917-935
LA: English
ER: F (Freshwater)
AB: In situ mesocosms in two Canadian Shield lakes were used to evaluate the contributions of in-lake vs. external sources of nitrogen and phosphorus to nutrient budgets and N:P ratios. These mesocosms were designed to have variable exchange with sediments. Half were fertilized with N and P at a ratio great enough to ensure P limitation for most phytoplankton (atomic ratio, 33:1); the other half were fertilized at a ratio low enough to cause N limitation (4.4:1) in the absence of compensation mechanisms. For littoral mesocosms, sediments were a major source of N, but not of P. A comparison of mesocosms having sediments with one having a plastic floor indicated that sediment N return was derived largely from decomposing material at the sediment surface, rather than from deep sediments. Disproportionate returns of N from sediments, along with lower denitrification, reduced N limitation in the low N:P mesocosms. In pelagic mesocosms, which lacked sediment contact, N sub(2) fixation and thermocline entrainment late in the experiment were the principal internal N sources at low N:P.
AN: 2831166
913 of 1521
TI: Benthic boundary layer communities and carbon cycling at abyssal depths in the Central North Pacific.
AU: Smith,-K.L.,Jr.
AF: Mar. Biol. Res. Div., 0202, Scripps Inst. Oceanogr., UCSD, La Jolla, CA 92093-0202, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 5, pp. 1034-1056
LA: English
ER: M (Marine)
AB: Cycling of carbon through the benthic boundary layer (BBL) community in the deep sea is poorly understood. Until now, attempts to summarize the flow of organic C in these communities have relied primarily on data collected from various deep-sea areas. The one BBL community where the organic C pools and fluxes are best defined is in the central North Pacific, north of the Hawaiian Islands. This data base was combined with new estimates of standing stocks and organic C fluxes to construct an organic C budget for the bottom 600 m of the water column and the sediments, using net input from sinking particulate organic C (POC) and exchanges between 12 compartments. The largest standing stocks of C (dissolved organic C, suspended POC, and POC) were in the water and surface sediments (9.1 x 10 super(8) g C km super(-2)), exceeding that in the 10 consumer groups by almost four orders of magnitude. Of the consumer groups, the sediment nanobiota, meiofauna, and epibenthic megafauna had the most organic C and the macrofauna had the least. Fluxes into the consumer groups, as estimated from respiration rates, were highest in the sediment community, bacterioplankton, and epibenthic megafauna.
AN: 2830941
914 of 1521
TI: The nitrogen:phosphorus relationship in lakes.
AU: Downing,-J.A.; McCauley,-E.
AF: Dep. Sci. Biol., Univ. Montreal, C.P. 6128, Succursale A, Montreal, Que. H3C 3J7, Canada
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 5, pp. 936-945
LA: English
ER: F (Freshwater)
AB: Published data on mean annual epilimnetic total N (TN) and P (TP) were analyzed to find how TN:TP varies with lake trophic status. TN:TP is high in oligotrophic lakes and very low in eutrophic lakes, declining in a curvilinear fashion with increased TP. Comparison of this trend with published N:P in lake nutrient sources suggests that TN:TP reflects the source of nutrients: the ratio is high in oligotrophic lakes because they receive their N and P from natural, undisturbed watersheds which export much less P than N; mesotrophic and eutrophic lakes receive various mixtures of nutrient sources that have lower average N:P; and very eutrophic lakes have N:P that correspond very nearly to the N:P of sewage. Two inflection points were identified in the TN:TP relationship ( similar to 20 and similar to 100 mu g TP/liter) the first probably reflecting the large difference between TN:TP in nutrient export from undisturbed terrestrial ecosystems and that of meso- and eutrophic sources such as urban and pasture land runoff and sewage, and the second probably reflecting increased rates of denitrification in eutrophic lakes.
AN: 2830754
915 of 1521
TI: Epilithic extracellular enzyme activity in acid and calcareous headstreams.
AU: Chappell,-K.R.; Goulder,-R.
AF: Dep. Appl. Biol., Univ. Hull, Hull HU6 7RX, UK
SO: ARCH.-HYDROBIOL. 1992. vol. 125, no. 2, pp. 129-148
NT: Bibliogr.: 40 ref.
LA: English
ER: F (Freshwater)
AB: Extracellular enzyme activity of intact epilithon on small stones from headstreams was assayed using 4-methylumbelliferyl substrates. The stones were collected from seven calcareous streams and eight, sometimes acid, streams on millstone grit in N England. Epilithic glycosidase ( beta -D-glucosidase, beta -D-galactosidase, beta -D-xylosidase) and sulphatase activity was greater in the calcareous streams but phosphatase activity was greater in the millstone-grit streams. In most streams the activity of phosphatase > beta -D-glucosidase > beta -D-galactosidase, beta -D-xylosidase and sulphatase. Correlation coefficients and multiple-regression analysis suggested the epilithic enzyme activities were potentially controlled by water quality variables (pH, temperature, conductivity, A sub(320)) and epilithic microbial variables (bacterial activity, total bacteria, chlorophyll-a) but not by variables which described stone character and location (stone size, water velocity and depth).
AN: 2829872
916 of 1521
TI: Effects of increasing levels of CO sub(2) and O sub(2) derived compounds on biogeochemical cycles and shaping of the biosphere.
AU: Penuelas,-J.
AF: Inst. Rec. y Tecnol. Agroaliment., Cent. Cabrils, Crtra. de Cabrils, s/n. 08348 Barcelona, Spain
SO: HOMAGE-TO-RAMON-MARGALEF;-OR,-WHY-THERE-IS-SUCH-PLEASURE-IN-STUDYING-NATURE. Ros,-J.;Prat,-N.-eds. BARCELONA-SPAIN UNIV.-DE-BARCELONA 1992. no. 10 pp. 367-385
ST: OECOL.-AQUAT.-SPEC.-ISS.. no. 10
LA: English
ER: B (Brackish)
AB: Plants reduce CO sub(2) to molecular species of increasing energy content. These compounds are then moved by heterotrophic organisms through decreasing energy levels as the organic matter is returned to inorganic form by successive oxidations. Thus, CO sub(2) and O sub(2) are the major substrates of biospheric reactions. Oxygen is toxic for anaerobic and, in excess, for aerobic organisms. Its toxicity is overcome by aerobic organisms by using it as an electron terminal acceptor in respiration and by developing biochemical defenses. It still determines phenomena such as anaerobiosis, the depth limit of higher aquatic plants, or bioluminescence, and perhaps others like the diurnal vertical migration of zooplankton. Low photosynthetic efficiency in light use, shape and color of vegetation may result from the peculiar availability of light and CO sub(2).
AN: 2829838
917 of 1521
TI: Methane metabolism in Baltic lakes of different trophic state.
OT: Methanhaushalt in baltischen Seen unterschiedlicher Trophiestufe
AU: Casper,-P.
AF: Inst. Gewaesseroekol. und Binnenfisch. Berlin e.V., Abt. Limnol., Alte Fischerhuette 2, D-O 1431 Neuglobsow, FRG
SO: LIMNOLOGICA. 1992. vol. 22, no. 2, pp. 121-128
NT: Bibliogr.: 30 ref.
LA: German
ER: F (Freshwater)
AB: Methane concentrations in different depths of the pelagic water columns and of sediment cores were examined in five lakes of the Lake Stechlin are and the Feldberg Lakes area. Measurements were carried out at the beginning of summer stagnation and of fall turnover. The highest methane concentrations were found near the sediment surface at the beginning of the stagnation period. The concentrations ranged from 0.1-10 mu mol/l in the water columns of the investigated oligotrophic and acidotrophic lakes to 10-100 mu mol/l in both eutrophic lakes. Methane production occurs in Lake Stechlin and Lake Fuchskuhle mainly below 15-20 cm sediment. In the eutrophic lakes methane is produced in the upper zone of sediments (0-3 cm) and during circulation in deeper zones (below 5 cm). The concentration of methane in the interstitial water reached in all investigated lakes below 5-10 cm sediment saturation levels (more than 1000 mu mol/l).
AN: 2826769
918 of 1521
TI: A device for in situ determination of geochemical transport parameters. 2. Biochemical reactions.
AU: Gillham,-R.W.; Starr,-R.C.; Miller,-D.J.
AF: Waterloo Cent. Groundwater Res., Dep. Earth Sci., Univ. Waterloo, Waterloo, ON N2L 3G1, Canada
SO: GROUND-WATER. 1990. vol. 28, no. 6, pp. 858-862
LA: English
ER: F (Freshwater)
AB: Chemical and biological reaction rates are required in estimating migration rates of many reactive contaminants in ground water, and as input data for mathematical models. Reaction rates must be measured, and depend on environmental conditions that are often difficult to duplicate in the laboratory. In situ rate measurement minimizes the difficulties of controlling environmental variables such as temperature, pH, Eh, DO, solution and solid phase composition, and bacterial population. The instrument described in this paper isolates a 1.9 liter portion of an aquifer for in situ biochemical rate measurement. The device has been used successfully to measure the rate of reactions involving inorganic and organic contaminants in sandy aquifers. Two applications of the device, measurement of denitrification rates and rates of biodegradation of benzene, are presented.
AN: 2824590
919 of 1521
TI: An advection/diffusion model for super(222)Rn transport in near-shore sediments inhabited by sedentary polychaetes.
AU: Benoit,-J.M.; Torgersen,-T.; O'-Donnell,-J.
AF: Dep. Mar. Sci., Univ. Connecticut, Groton, CT 06340, USA
SO: EARTH-PLANET.-SCI.-LETT. 1991. vol. 105, no. 4, pp. 463-473
LA: English
ER: M (Marine)
AB: A porewater solute transport model is proposed to explain the dissolved radon distributions in four profiles from a near-shore, marine site. The macro-infauna at the site is dominated by Clymenella torquata , a sedentary deposit feeding polychaete that actively irrigates its burrow. The model includes both an advective component that takes into account the (e.g.) C. torquata mechanism of burrow irrigation as well as enhanced diffusion-like transport brought about by mobile infauna. Because it explains the existence of subsurface radon minima with a constant source function and is based on the known irrigation habits of C. torquata , the model provides good fit to observed radon profiles and may be applicable to other solutes that display depth dependent minima.
AN: 2824414
920 of 1521
TI: Comparison of selenomethionine and selenite cycling in freshwater experimental ponds.
AU: Graham,-R.V.; Blaylock,-B.G.; Hoffman,-F.O.; Frank,-M.L.
AF: Environ. Sci. Div., Oak Ridge Natl. Lab., Oak Ridge, TN 37831-6036, USA
SO: WATER-AIR-SOIL-POLLUT. 1992. vol. 62, no. 1-2, pp. 25-42
LA: English
ER: F (Freshwater)
AB: A comparison of the cycling and fate of super(75)Se in an aquatic ecosystem was investigated when selenite or selenomethionine was introduced as an acute release into two experimental ponds. Biotic and abiotic compartments were periodically sampled to measure super(75)Se concentrations throughout the 318-d experiment. The biotic compartments were periphyton, rooted pondweed (Elodea canadensis ), snails (Helisoma sp.), and mosquitofish (Gambusia affinis ). Results show that the uptake rates in the biotic compartments for super(75)Se-selenomethionine were at least an order of magnitude greater than for super(75)Se-selenite. However, elimination rates for respective biotic compartments were similar. Seasonal sediment super(75)Se concentrations in both ponds decreased simultaneously with increases in super(75)Se concentrations within biotic compartments. This suggests that sediment is a secondary source of super(75)Se rather than a sink in some shallow freshwater systems.
AN: 2823857
921 of 1521
TI: Detrital pathways in a coral reef lagoon. 2. Detritus deposition, benthic microbial biomass and production.
AU: Hansen,-J.A.; Klumpp,-D.W.; Alongi,-D.M.; Dayton,-P.K.; Riddle,-M.J.
AF: Australian Inst. Mar. Sci., P.M.B. No. 3, Townsville M.C., Qld. 4810, Australia
SO: MAR.-BIOL. 1992. vol. 113, no. 3, pp. 363-372
NT: Bibliogr.: 39 ref.
LA: English
ER: M (Marine)
AB: We report the results of seasonal measurements, taken in 1986, of bacterial numbers and production, protozoan numbers, community primary production and respiration in the sediments of Davies Reef lagoon. Deposition rates of organic matter in the lagoon were also measured. Deposition rates ( plus or minus 1 SE) of carbon ranged from 9.2 ( plus or minus 1.5) to 140.7 ( plus or minus 10.3) mgCm super(-2)/d. Deposition rates were highest in winter and spring, lowest in summer. Rates of bacterial production ranged from 4.7 ( plus or minus 0.2) pmol thymidine incorporated/g dry wt (DW)/h in winter to 23.5 ( plus or minus 1.0) pmol thymidine incorporated/g DW/h in spring. The number of ciliates ranged from 65 ( plus or minus 10) to 356 ( plus or minus 50) cm super(-3) through the year and the number of large ( greater than or equal to 20 mu m) flagellates from 38 ( plus or minus 7) to 108 ( plus or minus 16) cm super(-3). There were no clear relationships between the sediment organic content, detrital input or temperature and the rates of bacterial processes, community metabolism or the standing stocks of microbes in the lagoon.
AN: 2823831
922 of 1521
TI: Interaction between dissolved organic matter in seawater and copper.
AU: Midorikawa,-T.; Tanoue,-E.; Sugimura,-Y.
AF: Geochem. Lab., Meteorol. Res. Inst., Nagamine 1-1, Tsukuba, Ibaraki 305, Japan
CO: 5. Int. Meet. of the Humic Substances Soc., Nagoya (Japan), 6-10 Aug 1990
SO: SCI.-TOTAL-ENVIRON. 1992. vol. 117-118, pp. 499-507
LA: English
ER: M (Marine)
AB: Dissolved organic matter in coastal seawater was investigated in terms of the interaction with copper. Three classes of organic ligands were distinguished from each other by differences in their complexing abilities for copper. Two ligands were determined by copper titration, using an ion selective electrode. Another ligand was detected by the competitive reaction for copper with an excess amount of EDTA. It was found that the third ligand was stronger than two ligands characterized by the copper titration method. The occurrence of a ligand having a high affinity for copper suggests the possible importance of organic ligands on the geochemical cycle of copper in the ocean.
AN: 2821371
923 of 1521
TI: Impact of oceanic sources of biogenic sulphur on sulphate aerosol concentrations at Mawson, Antarctica.
AU: Prospero,-J.M.; Savoie,-D.L.; Saltzman,-E.S.; Larsen,-R.
AF: Univ. Miami, RSMAS/MAC, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
SO: NATURE. 1991. vol. 350, no. 6315, pp. 221-223
LA: English
ER: M (Marine)
AB: Sulphate is the dominant aerosol species in the Antarctic atmosphere and an important constituent in Antarctic snow and ice. Various sources have been suggested for Antarctic non-sea-salt sulphate (n.s.s. SO sub(4)@) super(2)-:) volcanic emissions, stratospheric injection, pollutants transported from the low latitudes and biogenic dimethylsulphide (DMS) from the ocean. Although the oceanic source is now believed to be especially important, there has been no strong chemical evidence directly linking oceanic DMS with the Antarctic n.s.s. SO sub(4)@) super(2)-c)oncentrations. Here we present extended measurements from the Antarctic for both n.s.s. SO sub(4)@) super(2)-a)nd methanesulphonate (MSA), an oxidation product of DMS. Both species have a very strong seasonal cycle with a maximum in the austral summer.
AN: 2821245
924 of 1521
TI: Effects of forest herbicide applications on streamwater chemistry in southwestern British Columbia.
AU: Feller,-M.C.
AF: Fac. For., Univ. British Columbia, Vancouver, B.C. V6T 1W5, Canada
SO: WATER-RESOUR.-BULL. 1989. vol. 25, no. 3, pp. 607-616
LA: English
ER: F (Freshwater)
AB: The herbicide glyphosate was applied to portions of two watersheds in southwestern British Columbia to kill vegetation that was competing with Pseudotsuga menziesii (Douglas-fir) plantations. This application had little significant effect on streamwater chemistry when vegetation cover in a watershed was reduced by 4%, but has significant effects, which lasted for at least five years, when cover was reduced by 43%. In this case, most parameters increased in value following the application. In watersheds similar to those of the study area, herbicide application is likely to have a greater impact on streamwater chemistry, in general, than would clearcutting or clearcutting followed by slashburning.
AN: 2820367
925 of 1521
TI: Impact of atmospheric deposition on particulate manganese and aluminium distribution in northwestern Mediterranean surface water.
AU: Davies,-J.E.; Buat-Menard,-P.
AF: Cent. Faibles Radioact., Lab. Mixte CNRS-CEA, Domaine CNRS, F-91198 Gif-sur Yvette Cedex, France
SO: PALAEOGEOGR.,-PALAEOCLIMATOL.,-PALAEOECOL. 1990. vol. 89, no. 1-2, pp. 35-45
LA: English
ER: M (Marine)
AB: Sediment-trap samples and upper-water-column profiles of suspended particulate matter were collected at 42 degree 44'N, 8 degree 31'E in the northwestern Mediterranean Sea during 1987 as part of the French DYFAMED programme. Particulate sediment-trap samples and suspended particulate matter were analysed for aluminium and manganese. In specified samples, fecal-pellet fluxes were also measured. Concurrent manganese and aluminium atmospheric-depositional fluxes measured at Capo Cavallo, Corsica, 20 km from our sampling site were available for the corresponding sampling period for data interpretation. The results show that on a yearly basis the atmospheric input (1.6 mg Al/m super(2)/day and 30.6 mu g Mn/m super(2)/day) is sufficient to be the major source of both particulate aluminium and particulate (LE(leachable) + RE(refractory)) manganese in the sediment-trap flux at a depth of 200 m (2.2 mg Al/m super(2)/day and 22.5 mu g Mn/m super(2)/day). Significant correlation between both particulate-aluminium and refractory-particulate-manganese fluxes and the fecal-pellet fluxes shown that the settling flux of atmosphere mineral matter is probably governed by zooplankton grazing.
AN: 2819134
926 of 1521
TI: Modelling the biogenic transport of atmospheric particles in the Mediterranean Sea.
AU: Ruiz-Pino,-D.P.; Lambert,-C.E.; Jeandel,-C.; Buat-Menard,-P.
AF: Lab. Phys. et Chim. Mar., Univ. Paris 6, UA CNRS, B.P. 8, F-06230 Villefranche-sur-mer, France
SO: PALAEOGEOGR.,-PALAEOCLIMATOL.,-PALAEOECOL. 1990. vol. 89, no. 1-2, pp. 47-64
LA: English
ER: M (Marine)
AB: To help the assessment of the geochemical impact of sporadic events such as Saharan dust storms on the biogeochemical cycles of trace elements in the Mediterranean Sea, a one-dimensional multilayered model of the transport of atmospheric particles in the water column was developed. The model used data of the DYFAMED programme. Particulate aluminium was taken as a tracer of mineral particles. The Al atmospheric-source function was based on time-series data obtained at a coastal station in the Ligurian Sea. The response time throughout the water column was modulated by zooplankton grazing and water stratification. Stratification varies during the course of the year and induces variations of the eddy diffusivity coefficients which were calculated for the surface and deep layers. Runs of the model over one year displayed strong seasonal variations in particulate aluminium concentration and flux which agree with experimental data. Temporal changes of the particulate flux out of the euphotic zone are also clearly affected by the intensity and duration of the dust storm. The highest values of particulate flux occur as a consequence of the removal of dust particles from the surface layer when biological activity is high.
AN: 2819003
927 of 1521
TI: Recent improvements of ammonium and total phosphorus analysis in sea water.
AU: Degobbis,-D.; Ivancic,-I.
AF: "Ruder Boskovic" Inst., Cent. Mar. Res., 52210 Rovinj, Yugoslavia
SO: OEBALIA. 1991. vol. 17,N.S., pp. 221-235
LA: English
ER: M (Marine)
AB: Recent efforts to improve the analytical methods for ammonium and total phosphorus determinations in seawater are briefly reviewed. Some notes on seawater sample storage and treatment are also given.
AN: 2815434
928 of 1521
TI: The importance of denitrification.
OT: Typenpoiston tarpeellisuudesta
AU: Seppaenen,-H.
SO: VESITALOUS. 1992. vol. 33, no. 1, pp. 6-11
LA: Finnish
AN: 2814459
929 of 1521
TI: Deposit feeding and sediment: 2. Decomposition of fecal pellets of Holothuria tubulosa (Holothurioida, Echinodermata).
AU: Amon,-R.M.W.; Herndl,-G.J.
AF: Univ. Texas at Austin, Mar. Sci. Inst., P.O. Box 1267, Port Aransas, TX 78373, USA
SO: P.S.Z.N.-I:-MAR.-ECOL. 1991. vol. 12, no. 2, pp. 175-184
LA: English
ER: M (Marine)
AB: The effect of defecation and decomposition of fecal pellets egested by the deposit feeding Holothuria tubulosa on the microbial productivity of sediments was investigated in microcosm experiments. H. tubulosa specimens were collected from a 5 m deep seagrass meadow in the nearshore waters of the Mediterranean Sea off Lacco Ameno (Island of Ischia, Gulf of Naples, Italy). Experiments were performed under different temperature regimes. Bacterial production in the incubation media and within fecal pellets increased with increasing temperature. Incubation experiments on the effect of feces on natural sediments indicated that fecal pellet production by H. tubulosa enhanced sediment bacterial production by about 30%. Two independent methods were used to estimate leaching of dissolved carbohydrates from fecal pellets. One method was based on the increase in total dissolved carbohydrates in the incubation medium, the other on the decrease in total particulate carbohydrates of the fecal matter.
AN: 2813482
930 of 1521
TI: Deposit feeding and sediment: 1. Interrelationship between Holothuria tubulosa (Holothurioida, Echinodermata) and the sediment microbial community.
AU: Amon,-R.M.W.; Herndl,-G.J.
AF: Univ. Texas at Austin, Mar. Sci. Inst., P.O. Box 1267, Port Aransas, TX 78373, USA
SO: P.S.Z.N.-I:-MAR.-ECOL. 1991. vol. 12, no. 2, pp. 163-174
LA: English
ER: M (Marine)
AB: The feeding of the epibenthic deposit-feeder Holothuria tubulosa and its influence on sediment metabolism was investigated from February 1988 to February 1989. Water samples, specimens of H. tubulosa , and samples of freshly egested feces were taken by SCUBA diving in a 5 m deep seagrass bed at the Island of Ischia in the Gulf of Naples (Italy). Particulate organic carbon (POC), particulate organic nitrogen (PON), total particulate carbohydrates (PCHO), and bacterial biomass exhibited higher values in the foregut than in the surrounding sediment. Even the freshly egested feces were richer in the organic components than the sediment. The percentage of growing bacterial cells increased from 4.1% in the sediment to 12.2% in the foregut and declined to 11.6% in the hindgut and 6.2% in freshly egested feces.
AN: 2813469
931 of 1521
TI: The detritic compartment in a Posidonia oceanica meadow: Litter features, decomposition rates, and mineral stocks.
AU: Romero,-J.; Pergent,-G.; Pergent-Martini,-C.; Mateo,-M.-A.; Regnier,-C.
AF: Dep. Ecol., Univ. Barcelona, Diagonal 645, E-08028 Barcelona, Spain
SO: P.S.Z.N.-I:-MAR.-ECOL. 1992. vol. 13, no. 1, pp. 69-83
LA: English
ER: M (Marine)
AB: The ecosystem associated to the Mediterranean seagrass Posidonia oceanica shows a clear distinction in two subcompartments regarding turnover time: aboveground and belowground. Aboveground parts (leaves) are highly dynamic, and most of the leaf material is decomposed or exported in less than one year, representing a net loss of nutrients. In contrast, belowground biomass (roots and rhizomes) has a turnover time of the order of centuries, with a consequent accumulation of organic matter in the sediment. The accumulation rates for the single elements rank in the order C > N > P. This ecosystem may be considered as a sink for biogenic elements.
AN: 2813318
932 of 1521
TI: Early diagenesis of organic matter in the water column and sediment in a eutropic lake: Lake of Aydat (Puy-de-Dome, France).
OT: Diagenese precoce de la matiere organique dans la colonne d'eau et le sediment d'un lac eutrophe: Le lac d'Aydat (Puy-de-Dome)
AU: Sarazin,-G.; Devaux,-J.
AF: Univ. Paris VII, Lab. Geochim. Eaux, 75251 Paris Cedex 05, France
CO: Les Lacs comme Modele d'Ocean, Paris (France), 23 Nov 1990
SO: LAKES-AS-OCEAN-MODELS,-23-NOVEMBER-1990. LES-LACS-COMME-MODELE-D'-OCEAN,-23-NOVEMBRE-1990. Pourriot,-R.-ed. 1991. vol. 17, no. 5 pp. 533-560
ST: OCEANIS-DOC.-OCEANOGR.. vol. 17, no. 5
LA: French
ER: M (Marine)
AB: The acquisition of a large number of data concerning the water column and the sediment pore water of a eutrophic lake (Lake of Aydat, Puy-de-Dome, France) enabled us to determine the main biogeochemical processes responsible for the mineralization of organic matter produced within the lacustrine ecosystem. In the oxygenated epilimnion, during the summer stratification period, direct oxidation with oxygen prevails. Within the anoxic hypolimnion the main oxidants are particulate and insoluble ferric and manganic compounds; at the same time the disproportionation of organic matter releases equivalent amounts of CO sub(2) and CH sub(4) via bacteria. With the exception of oxygen, the same electron acceptors are found in the pore water medium. Stoichiometric modeling provides us with a global formula for organic matter undergoing these reactions. The C:N ratio is nearly identical to that of Redfield, while the difference observed in the C:P ratio is explained by a close coupling of the chemistries of iron and phosphorus.
AN: 2813028
933 of 1521
TI: Sulfur: The plankton/climate connection.
AU: Malin,-G.; Turner,-S.M.; Liss,-P.S.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: J.-PHYCOL. 1992. vol. 28, no. 5, pp. 590-597
LA: English
ER: M (Marine)
AB: A key process in the global sulfur cycle is the transfer of volatile forms of the element from sea to land via the atmosphere. Early budgets calculated the amount of sulfur required to balance the cycle and generally assumed that this flux was achieved by formation of hydrogen sulfide (H sub(2)S) in coastal waters, mud flats, etc. However, Lovelock et al. (1972) made the first field measurements of dimethylsulfide (DMS) in seawater and suggested that it represented the missing link in the S cycle. In this review we consider processes leading to the formation of DMS in seawater, its emission to the atmosphere, and transformation therein, the possible role of DMS oxidation products in climate regulation as proposed by Charlson et al. (1987), and how global changes might affect DMS production.
AN: 2812490
934 of 1521
TI: Remote sensing of oceanic biology in relation to global climate change.
AU: Aiken,-J.; Moore,-G.F.; Holligan,-P.M.
AF: Nat. Environ. Res. Counc., Plymouth Mar. Lab., Prospect Pl., West Hoe, Plymouth PL1 3DH, UK
SO: J.-PHYCOL. 1992. vol. 28, no. 5, pp. 579-590
LA: English
ER: M (Marine)
AB: This review of the remote sensing of oceanic phytoplankton has indicated how the CZCS, despite instrumental limitations of spectral resolution and sensitivity, has produced a wealth of new information on biomass distributions and provided the basis for new approaches to the estimation of global marine primary productivity. Simulations of new ocean color sensors such as SeaWiFS, based on aircraft multispectral data, indicate a significant improvement in performance and accuracy compared to the CZCS, with only a modest change in specification in terms of the addition of sensor channels in the infrared for atmospheric corrections and visible bands for better pigment estimates.
AN: 2812477
935 of 1521
TI: Landscape properties of pocosins and associated wetlands.
AU: Brinson,-M.M.
AF: Dep. Biol., East Carolina Univ., Greenville, NC 27858, USA
SO: WETLANDS. 1991. vol. 11, no. Sp. Iss., pp. 441-466
NT: Spec. Iss.: Advanced identification in Pocosins.
LA: English
ER: F (Freshwater)
AB: Most pocosins occur on broad, relatively flat interfluves or near estuaries where rising sea level affects their hydrology. Traditionally accepted ecological functions are low when compared on a unit area basis with other wetland types. An understanding of the interaction of pocosins with the atmosphere is fundamental to revealing mechanisms for their formation and their importance in landscape-level biogeochemical processes such as producing and consuming greenhouse gases and receiving and processing acid deposition. At least four interactions between pocosins and estuaries are important at landscape scales: maintaining landscape elevation in the context of rising sea level, representing a platform upon which landward migrating brackish marshes can develop, exporting high concentrations of organic carbon, and influencing the quality of habitat in primary nursery areas for fish and shellfish. Since pocosins have lower rates of cycling for most elements, greater surface area of pocosin is required to provide the same function and life support as floodplain wetlands.
AN: 2812163
936 of 1521
TI: Chemical, isotopic, spectroscopic and geochemical aspects of natural and synthetic humic substances.
AU: Ikan,-R.; Ioselis,-P.; Rubinsztain,-Y.; Aizenshtat,-Z.; Miloslavsky,-I.; Yariv,-S.; Pugmire,-R.; Anderson,-L.L.; Woolfenden,-W.R.; et-al.
AF: Dep. Org. Chem., Hebrew Univ., Jerusalem, Israel
CO: 5. Int. Meet. of the Humic Substances Soc., Nagoya (Japan), 6-10 Aug 1990
SO: SCI.-TOTAL-ENVIRON. 1992. vol. 117-118, pp. 1-12
LA: English
ER: M (Marine)
AB: It has been suggested that marine humic and fulvic acids are formed by a condensation of sugars with amino acids or proteins via Maillard reaction. In order to investigate this hypothesis a series of melanoidins were synthesised under laboratory conditions and their structure compared with natural humic acids. An extensive collaborative research programme on the chemical and physical properties of natural and synthetic humic substances has been undertaken using spectroscopic, chromatographic, thermogravimetric, pyrolytic oxidative and isotopic methods. The results indicate that various heterocyclic moieties are the main building blocks of humic substances rather than aromatic benzenoid structures.
AN: 2811759
937 of 1521
TI: Pacific CaCO sub(3) preservation and delta super(18)O since 4 Ma: Paleoceanic and paleoclimatic implications.
AU: Farrell,-J.W.; Prell,-W.L.
AF: Dep. Geol. Sci., Brown Univ., Providence, RI, USA
SO: PALEOCEANOGRAPHY. 1991. vol. 6, no. 4, pp. 485-498
LA: English
ER: M (Marine)
AB: The Pliocene-Pleistocene history of CaCO sub(3) preservation in the central equatorial Pacific is reconstructed from a suite of deep-sea cores and is compared to fluctuations in global ice volume inferred from delta super(18)O records. The results are highlighted by: (1) strong covariation between CaCO sub(3) preservation and ice volume over 10 super(4) to 10 super(6) year time scales; (2) a long-term increase in ice volume and CaCO sub(3) preservation since 3.9 Ma demonstrated by a deepening of the lysocline and the carbonate critical depth; (3) a dramatic shift to greater CaCO sub(3) preservation at 2.9 Ma; (4) distinctive ice-volume growth and CaCO sub(3) preservation events at 2.4 Ma, which are associated with the significant intensification of northern hemisphere glaciation; (5) a mid-Pleistocene transition to 100-kyr cyclicity in both CaCO sub(3) preservation and ice volume; and (6) a 600-kyr Brunhes dissolution cycle superimposed on the late Pleistocene glacial/interglacial 100-kyr cycles. CaCO sub(3) preservation primarily reflects the carbonate chemistry of abyssal waters and is controlled by long-term (10 super(6) year) and short-term (10 super(4) to 10 super(5) year) biogeochemical cycling and by distinct paleoclimatic events.
AN: 2811192
938 of 1521
TI: In situ studies on transformation of organic matter by Mytilus galloprovincialis .
AU: Baudinet,-D.; Grenz,-C.; Masse,-H.
AF: Inst. Maurice Lamontagne, Mont-Joli, Canada
CO: Aquaculture '92, Orlando, FL (USA), 21-25 May 1992
SO: AQUACULTURE-'-92:-GROWING-TOWARD-THE-21st-CENTURY. 1992. p. 37
NT: Summary only.
LA: English
ER: M (Marine)
AB: In situ multiparameter studies were driven for three years in a Mediterranean shellfish farming ecosystem to observe direct and indirect transformations of organic matter by a benthic filter feeder, Mytilus galloprovincialis . Chemical parameters measured in the water column and at the sediment-water interface from a reference station (without mussels) and another one located in a mussel rope hanging structure (a mussel table), are compared. One mussel production unit modifies an equivalent volume of water by a significant transformation of particulate and dissolved matter: 40% of the available potential energy contained in particulate organic matter, 21% of the particulate carbon and particulate nitrogen, 70% of the dissolved free amino acids were removed; phaeopigments (40%), as well as ammonia (84%) and urea (25%) are increased. The ammonia released by excretion is 37 times higher than provided by biodeposit mineralisation. From these results, a nitrogen budget for a mussel production unit is proposed.
AN: 2810102
939 of 1521
TI: Bioturbation by Nereis sp. and its effects on the phosphate flux across the sediment-water interface in the Palmones River estuary.
AU: Clavero,-V.; Fernandez,-J.A.; Niell,-F.X.
AF: Dep. Ecol., Fac. Sci., Malaga Univ., 29071 Malaga, Spain
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: SEDIMENT-WATER-INTERACTIONS. Hart,-B.T.;Sly,-P.G.-eds. 1992. vol. 235-236 pp. 387-392
ST: HYDROBIOLOGIA. vol. 235-236
LA: English
ER: M (Marine); B (Brackish)
AB: The effects of Nereis sp. on the flux of dissolved phosphate across the sediment-water interface has been studied in Palmones River estuary using benthic flux-chambers and intact cores. Diffusive fluxes of phosphate were calculated from pore water gradient concentration and compared with those obtained from benthic chambers experiments. The high abundance of Nereis in the upper sediment layers appears to play an important part in the dissolved oxygen profiles in the overlying water, but had no effect on the redox potential. A negative relationship was found between the Nereis abundance and the phosphate gradient; this gradient ranged between 40 mu mol/l/cm with 340 Nereis individuals m super(-2) and 20 mu mol/l/cm with 900 Nereis individuals m super(-2). The ratio of the in situ flux to the flux gradient concentration for dissolved phosphate increased with the abundance of Nereis (from 1.7 at low abundance to 5.8 at high abundance).
AN: 2805873
940 of 1521
TI: Sediment/water interactions.
AU: Hart,-B.T.; Sly,-P.G.-(eds.)
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: HYDROBIOLOGIA. 1992. vol. 235-236, 743 pp
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The Fifth Symposium on Sediment/Water Interactions was held in Uppsala, Sweden, 6-9 August, 1990. As in previous proceedings, the preface has been used to highlight scientific advances and the significance of particular contributions. The papers appearing in this issue of Hydrobiologia reflect the current attention in sediment/water science to five main topics of investigation: Sediment dynamics in estuaries, coastal waters, lakes, reservoirs and rivers; Sediment-associated biological processes; Contaminant accumulation, distribution and geochemistry; Fluxes from sediments; and Element cycling.
AN: 2805371
941 of 1521
TI: Sulphur isotope ratios in sulphate and oxygen isotopes in water from a small watershed in central Sweden.
AU: Andersson,-P.; Torssander,-P.; Ingri,-J.
AF: Div. Geol. and Planet. Sci., California Inst. Technol., Pasadena, CA 91125, USA
CO: 5. Int. Symp. on Sediment/Water Interactions, Uppsala (Sweden), 6-9 Aug 1990
SO: SEDIMENT-WATER-INTERACTIONS. Hart,-B.T.;Sly,-P.G.-eds. 1992. vol. 235-236 pp. 205-217
ST: HYDROBIOLOGIA. vol. 235-236
LA: English
ER: F (Freshwater)
AB: During 1988-89 water samples for sulphur and oxygen isotope measurements were collected in the Lake Mjoesjoen watershed (7.3 km super(2)), central Sweden. Samples included: precipitation, throughfall, lakewater, shallow groundwater and inlet and outlet streams. The delta super(34)S of sulphate in precipitation ranged from + 6.41 ppt in winter to + 3.88 ppt in summer, the higher winter values attributed to seasonal differences in the kinetic and equilibrium isotope fractionation during oxidation of atmospheric sulphur dioxide to sulphate. The delta super(34)S in rain samples and in pine and spruce throughfall were similar, indicating no gain of sulphur from the trees. In the inflowing stream, the delta super(34)S value increased as discharge decreased, from + 5.57 ppt spring to + 26.21 ppt in summer, indicating bacterial sulphate reduction. The fluctuations in the inlet water were damped by the lake and in the outlet water, only a small decrease in the delta super(34)S value during spring discharge was observed.
AN: 2805125
942 of 1521
TI: Biotic feedbacks in lake phosphorus cycles.
AU: Carpenter,-S.R.; Cottingham,-K.L.; Schindler,-D.E.
AF: Cent. Limnol., 680 N. Park St., Univ. Wisconsin, Madison, WI 53706, USA
SO: TRENDS-ECOL.-EVOL. 1992. vol. 7, no. 10, pp. 332-336
LA: English
ER: F (Freshwater)
AB: Limnologists are now reconsidering the role of the biota in the phosphorus (P) cycles of lakes. Changes in the lake communities can have significant consequences for ecosystem P cycles. At seasonal timescales, the relative importance of nitrogen (N) and P as limiting factors for primary production depends in part on zooplankton species composition. Phosphorus storage and recycling by fish and zooplankton can be large components of P budgets, and mobile consumers can be important vectors in P transport. Stability, resilience and resistance of lake P cycles may depend heavily on fluxes to and from upper trophic levels.
AN: 2804892
943 of 1521
TI: Determination of phytoplankton chlorophyll concentrations in the Chesapeake Bay with aircraft remote sensing.
AU: Harding,-L.W.,Jr.; Itsweire,-E.C.; Esaias,-W.E.
AF: Univ. Maryland Sea Grant Coll., 1123 Taliaferro Hall, College Park, MD 20742, USA
SO: REMOTE-SENS.-ENVIRON. 1992. vol. 40, no. 2, pp. 79-100
LA: English
ER: M (Marine); B (Brackish)
AB: This article describes remote sensing measurements of the distribution of phytoplankton chlorophyll concentrations in the Chesapeake Bay during 1989. The goal of this study was to show that remote sensing from light aircraft can complement and extend measurements made from traditional platforms and provide data of improved temporal and spatial resolution, leading to a better understanding of phytoplankton dynamics in the estuary. We followed the developments of the winter-spring diatom bloom in the polyhaline to mesohaline regions of the estuary and of the late-spring and summer dinoflagellate blooms in oligohaline and mesohaline regions.
AN: 2799956
944 of 1521
TI: New and recycled primary production in an oligotrophic lake: Insights for summer phosphorus dynamics.
AU: Caraco,-N.F.; Cole,-J.J.; Likens,-G.E.
AF: Inst. Ecosyst. Stud., New York Bot. Gard., Box AB, Millbrook, NY 12545-0129, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 3, pp. 590-602
LA: English
ER: F (Freshwater)
AB: Primary production that is supported by new inputs of nutrients from outside the system is distinct from production that is supported by remineralization of nutrients within the system. We applied the concept of new production to Mirror Lake, New Hampshire, and our view of P dynamics in this lake was altered dramatically. New production during midsummer put a large demand on P in surface waters, removing 37 mu mol P m super(-2)/d. Without new inputs of P, the P content of surface waters would drop to zero in < 1 month. There is, however, a slight increase, not a decrease, in P content of surface waters during summer stratification. Inputs to surface waters during summer months must, therefore, be large. We now believe that higher than average P loading to the lake occurs in summer, despite low runoff inputs.
AN: 2799318
945 of 1521
TI: Detritus, macrophytes and nutrient cycling in lakes.
AU: Wetzel,-R.G.
AF: Dep. Biol., Univ. Alabama, Tuscaloosa, AL 35487, USA
SO: SCIENTIFIC-PERSPECTIVES-IN-THEORETICAL-AND-APPLIED-LIMNOLOGY. De-Bernardi,-R.;Giussani,-G.;Barbanti,-L.-eds. 1990. vol. 47 pp. 233-251
ST: MEM.-IST.-ITAL.-IDROBIOL. vol. 47
LA: English
ER: F (Freshwater)
AB: Detritus in aquatic ecosystems consists of much greater amounts of organic carbon than occur in the biota. Even though most detritus occurs as dissolved organic carbon and most of the organic carbon is relatively recalcitrant to rapid decomposition, the slow degradation of large amounts of organic matter results in ecosystem detrital metabolism usually far in excess of carbon fluxes by the trophic-dynamic grazing and predatory biota. Detritus and metabolism associated with particulate and especially dissolved detritus provides detrital energy essential for the operation and metabolic stability of the entire ecosystem.
AN: 2799317
946 of 1521
TI: The cycling of iron and manganese in the water column of Lake Sammamish, Washington.
AU: Balistrieri,-L.S.; Murray,-J.W.; Paul,-B.
AF: U.S. Geol. Surv., Sch. Oceanogr., WB-10, Univ. Washington, Seattle, WA 98195, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 3, pp. 510-528
LA: English
ER: F (Freshwater)
AB: Processes controlling the distribution and mobility of Fe and Mn in Lake Sammamish, Washington, a seasonally anoxic lake, are deduced from a year-long monthly study of physical, chemical, and biological parameters in the lake. Inventories of dissolved Mn and Fe in the bottom waters increase as the redox potential lowers with dissolved Mn inventories during stagnation being much larger than inventories of dissolved Fe. The shapes of the dissolved metal profiles indicate that dissolved Fe is supplied to the hypolimnion during stratification by diffusion of Fe(II) from the sediments into the overlying anoxic water as well as reduction of Fe oxide particles settling through the anoxic water column, while the dominant source of dissolved Mn to the anoxic bottom waters during most of the stratification period appears to be reduction of settling Mn-oxide particles. Inventories of particulate Fe in the hypolimnion during the latter stages of stratification are significantly larger than inventories of particulate Mn.
AN: 2798185
947 of 1521
TI: The biogeochemical cycling of trace metals in the water column of Lake Sammamish, Washington: Response to seasonally anoxic conditions.
AU: Balistrieri,-L.S.; Murray,-J.W.; Paul,-B.
AF: U.S. Geol. Surv., Sch. Oceanogr., WB-10, Univ. Washington, Seattle, WA 98195, USA
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 3, pp. 529-548
LA: English
ER: F (Freshwater)
AB: Total acid-soluble and dissolved Cd, Co, Cr, Cu, Ni, Pb, and Zn concentrations in the water column of a seasonally anoxic lake (Lake Sammamish, Washington) were measured on a monthly basis during the course of a year. These data, in conjunction with Fe, Mn, sulfide, and nutrient data, are used to assess the biochemical processes controlling the distribution of trace metals in the lake and how the importance of these processes varies with time. Thermodynamic calculations are used to examine changes in dissolved metal speciation in the bottom waters during the year and to assess the saturation state of metal-sulfide phases. Spatial and temporal changes in the redox conditions of the bottom waters result in increases in dissolved Co and Ni concentrations, peaks in particulate Co profiles, decreases in dissolved Cu and Cr concentrations, and significant changes in dissolved metal speciation during stagnation. The redox-driven cycling of Fe and Mn in the hypolimnion has a dramatic effect on Co distributions, a slight effect on Ni concentrations, and virtually no effect on Cd, Cu, Cr, and Zn concentrations. Biological uptake and regeneration processes result in a correlation between Zn and silicate concentrations throughout the water column, and it appears that biological cycling may also influence the distribution of Cd.
AN: 2797995
948 of 1521
TI: Changes in the balances of non-fossil carbon, nitrous oxide and dimethyl sulfide in the North Sea.
AU: Hoppema,-J.M.J.; De-Baar,-H.J.W.
CA: Nederlands Inst. voor Onderzoek der Zee, Texel (Netherlands)
SO: 1991. 92 pp
NT: NTIS Order No: PB92-104850/GAR.
LA: English
ER: M (Marine)
AB: The overview provides an assessment of the current knowledge of the anthropogenic impact on the possible emission or uptake of the radiatively-important gases CO2, CH4, N2O and DMS by the North Sea, with special emphasis on the continental shelf waters of the Netherlands. The final objective would be to describe the undisturbed biogeochemical cycles in which these gases are involved, but unfortunately in most cases anthropogenic influence has been exerted for many years and in the absence of historical records of measurements it is impossible to reconstruct the original situation (approx 1860). Therefore, one is restricted to a description of the present-day cycles along with an assessment of the changes that already took place. For understanding the changes in the cycling of radiatively-important gases caused by anthropogenic activity it is necessary to know the processes and mechanisms that determine biogeochemical transformations within these cycles. For this purpose the most important production and consumption processes and the transfers of the matter through the overall North Sea reservoir were treated as well.
AN: 2797132
949 of 1521
TI: Pyrosoma atlanticum (Tunicata, Thaliacea): Grazing impact on phytoplankton standing stock and role in organic carbon flux.
AU: Drits,-A.V.; Arashkevich,-E.G.; Semenova,-T.N.
AF: Inst. Oceanol., Acad. Sci., 117218, Krasikova 23, Moscow, Russia
SO: J.-PLANKTON-RES. 1992. vol. 14, no. 6, pp. 799-809
LA: English
ER: M (Marine)
AB: Pyrosomas are a large group of pelagic tunicates whose trophic role in pelagic communities has not yet been sufficiently studied. We ran across a local area of high concentration of the most widespread and commonest species of pyrosomas, Pyrosoma atlanticum , 450 miles off the Congo river mouth. The following was estimated: gut pigment content, defecation rate, organic carbon and pigment content of fecal pellets, and sinking rate. Based on these data and the measured number of pyrosomas colonies the grazing impact on phytoplankton and the fecal pellet flux were calculated. During the night swarms of 50-65 mm P. atlanticum removed 53% of phytoplankton standing stock in the 0-10 m layer; sparsely distributed pyrosomas consumed only 4%. The grazing impact in the 0-50 m layer was only 12.5 and < 1% respectively. We believe that given the sinking rate of 70 m/day the main part of fecal material does not leave the upper water column and is retained in the trophic web of the epipelagic layer.
AN: 2796436
950 of 1521
TI: Contribution of the different planktonic microbial assemblages to ETS activity in the Ligurian frontal area: North-West Mediterranean Sea.
AU: Savenkoff,-C.; Silva,-N.L.; Lefevre,-D.; Denis,-M.; Rassoulzadegan,-F.
AF: Cent. Oceanol. Marseille, CNRS URA 41, Parc Sci. et Technol. Luminy, Case 901, 13288 Marseille Cedex 9, France
SO: J.-PLANKTON-RES. 1992. vol. 14, no. 6, pp. 835-850
LA: English
ER: M (Marine)
AB: Spatial and size distribution of microorganisms and their ETS activity has been investigated in Ligurian Sea surface waters along the Nice-Calvi transect across frontal areas from 18 to 37 km offshore. Aplastidic and plastidic nanoflagellates and aplastidic picoflagellates were present in numbers close to 0.25 x 10 super(4) cells/ml, whereas plastidic picoflagellates accounted for about half this number. Correlations have been evidenced between plastidic and aplastidic micro-organisms within the same size group, suggesting that they belong to a well-defined ecosystem. The highest correlation between total ETS activity and abundance of the considered size groups was observed for nanoflagellates (r = 0.94, n = 22, and r = 0.90, n = 22 for aplastidic and plastidic cells respectively). The importance of the role of nanoflagelaltes in surface waters, with respect to the overall ETS activity, was supported by results from size fractionation which assigned to the 3-10 mu m size range a 73.3% contribution to overall ETS activity. Results emphasize analysing global ETS activity of natural samples in order to derive relationships between the different populations present in the sampled water. It is suggested that coupling flow cytometry to the ETS approach should be very helpful in that respect.
AN: 2796054
951 of 1521
TI: Multiparametric investigation of North Sea particulate matter. Preliminary results in the Skagerrak.
OT: Etude multiparametrique des particules en Mer du Nord: Resultats preliminaires dans le Skagerrak
AU: Boust,-D.; Dupont,-J.P.; Bienvenu,-P.; Ezat,-U.; Lafite,-R.; Leboulanger,-T.; Vinchon,-C.; Albarede,-F.
AF: Lab. Radioecol. Mar., Cent. La Hague, Comm. Energ. Atom., B.P. 508, 50105 Cherbourg Cedex, France
CO: Int. Symp. sur l'Environnement des Mers Epicontinentales, Lille (France), 20-22 Mar 1990
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-SYMPOSIUM-ON-ENVIRONMENT-OF-EPICONTINENTAL-SEAS,-LILLE,-20-22-MARCH-1990.. ACTES-DE-COLLOQUE-INTERNATIONAL-SUR-L'-ENVIRONNEMENT-DES-MERS-EPICONTINENTALES,-LILLE,-20-22-MARS-1990. Chamley,-H.-ed. 1991. vol. sp.iss., no. 11 pp. 233-246
ST: OCEANOL.-ACTA. vol. sp.iss., no. 11
LA: English
ER: M (Marine)
AB: During the Tramanor cruise, in July 1988, seawater and particle samples were collected along a vertical profile (530 m depth) located in the Skagerrak, a crossing-area for different water-masses and particle pools. A sampling strategy was developed to ensure the homogeneity of the different sets of subsamples subjected to analysis by closely-coupled complementary techniques: turbidimetry, granulometry, scanning electron microscope (SEM) observations, Tracor analyses, particulate organic carbon and nitrogen measurements, and neutron activation analysis (NAA). The Baltic outflow is found in the topmost 20 m water-column (salinity approximately equals 23.5; temperature approximately equals 18 degree C) overlying North Sea waters (salinity approximately equals 35; temperature approximately equals 6 degree C). Surface waters undergo a plankton bloom, dominated by Dinoflagellates and Coccolithophoridae. The former, characterized by high C/N ratios ( approximately equals 15; cellulosic thecae), play a significant role in the biological recycling of Zn. The latter accumulate over the halocline as typically observed in frontal structures. The detrital phase mainly consists of clay minerals. Manganese is highly enriched relative to shale-type material together with Fe, Co and Zn.
AN: 2792439
952 of 1521
TI: Numerical modelling of biological-physical interactions in coastal sites.
OT: Modelisation numerique d'un couplage physico-biologique en milieu cotier
AU: Marcer,-R.; Fraunie,-P.; Dekeyser,-I.; Andersen,-V.
AF: Inst. Mecan. Stat. Turbulence, 13003 Marseille, France
CO: Int. Symp. sur l'Environnement des Mers Epicontinentales, Lille (France), 20-22 Mar 1990
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-SYMPOSIUM-ON-ENVIRONMENT-OF-EPICONTINENTAL-SEAS,-LILLE,-20-22-MARCH-1990.. ACTES-DE-COLLOQUE-INTERNATIONAL-SUR-L'-ENVIRONNEMENT-DES-MERS-EPICONTINENTALES,-LILLE,-20-22-MARS-1990. Chamley,-H.-ed. 1991. vol. sp.iss., no. 11 pp. 71-79
ST: OCEANOL.-ACTA. vol. sp.iss., no. 11
LA: French
ER: M (Marine)
AB: This study concerns the numerical simulation of the behaviour of pelagic systems in marine environments by means of a coupled biological and physical model. The physical model is based on the resolution of the Navier-Stokes, temperature and salinity equations in the 3 dimensions of space with a turbulent closure model consisting of 2 supplementary equations ( Kappa - epsilon model). The tridimensional biological model distinguishes 5 areas: phytoplankton (alive and dead); dissolved inorganic nitrogen; herbivores (essentially copepods); and zooplanktonic wastes (dead bodies and fecal pellets). Other than biological relations (nutrition, excretion,...), the sedimentation of biogenic particles (alive and dead phytoplanktonic cells, dead herbivores) are also considered. The established tridimensional velocity and dissipation fields are used as forcing variables for this biological model. This model has been applied in the case of a real bay configuration: the "baie de Cannes-Mandelieu".
AN: 2792095
953 of 1521
TI: Decomposition activity and nutrient regeneration rates in the hypolimnion of the north basin of Lake Biwa.
AU: Miyajima,-T.
AF: Cent. Ecol. Res., Kyoto Univ., Shimosakamoto, Otsu 520-01, Japan
SO: JAP.-J.-LIMNOL.-RIKUSUIZATSU. 1992. vol. 53, no. 1, pp. 65-73
LA: English
ER: F (Freshwater)
AB: In the course of a recent survey on nutrient dynamics in the north basin of Lake Biwa (Japan), an abundant accumulation of nitrate was observed in the hypolimnion during the stagnation period, and the regeneration rate of nitrogen in the hypolimnion was estimated to be 40.5 mmol/m super(2)/mon. However, it was calculated on the basis of oxygen consumption that the C:N ratio of organic matter mineralized within the hypolimnion should have been 19-21, which suggested a low regeneration efficiency of nitrogen relative to carbon. Dissolved phosphate was found to be accumulated in small concentrations near the bottom, but the regeneration rate of phosphate was very low (0.22 mmol/m super(2)/mon), and the activity of hypolimnetic biota seemed to contributed hardly at all to phosphorus recycling in this basin.
AN: 2791188
954 of 1521
TI: Measurements of nitrogen productivity in the Equatorial Pacific.
AU: Wilkerson,-F.P.; Dugdale,-R.C.
AF: Hancock Inst. Mar. Stud., Dep. Biol. Sci., Univ. Southern California, Los Angeles, CA 90089-6371, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C1, pp. 669-679
LA: English
ER: M (Marine)
AB: During the R/V Wecoma WEC88 cruise that sampled a meridional transect along 150 degree W from 15 degree N to 15 degree S, uptake of nitrate and ammonium by phytoplankton was measured using super(15)N with simulated in situ bottle incubations and shipboard mass spectrometry. A set of 25 daily productivity stations showed the influence of equatorial upwelling on nitrate distribution and super(15)N uptake in a band from 6 degree N to 7.5 degree S compared with the oligotrophic waters to the north and south, with the highest values of nitrate uptake occurring at the equator. During a 5-day time series at the equator, there was an increase in nitrate accompanied by increased nitrate uptake. Nitrate uptake rates at the equator were lower than those predicted by previous investigators. Holdover experiments and uptake versus irradiance curves showed that the phytoplankton there were in an early stage of metabolic adaptation.
AN: 2790910
955 of 1521
TI: Nitrate utilization by plankton in the Equatorial Pacific March 1988 along 150 degree W.
AU: Eppley,-R.W.; Renger,-E.H.
AF: Mar. Life Res. Group, Scripps Inst. Oceanogr., Univ. California, San Diego, CA 92093, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C1, pp. 663-668
LA: English
ER: M (Marine)
AB: Rates of nitrate utilization were measured in March 1988, from 6 degree N to 8 degree S on longitude 150 degree W in the Pacific Ocean. Surface waters in the equatorial upwelling contained about 5- mu M nitrate. Samples of seawater incubated on deck, as in primary production experiments, lost about 150-nM nitrate during the day and an equal amount at night at the equator. These rates exceeded by several fold the rates of nitrate incorporation into particulate matter. The carbon equivalent of the 24-hour nitrate consumption also exceeded the rate of super(14)C primary production. The large nitrate consumption is not readily explained in terms of phytoplankton physiology but may serve to fuel speculation on the possible production of dissolved organic nitrogen and on the role of bacteria in processing nitrate in the equatorial Pacific upwelling region.
AN: 2790885
956 of 1521
TI: Photosynthetic characteristics and estimated growth rates indicate grazing is the proximate control of primary production in the Equatorial Pacific.
AU: Cullen,-J.J.; Lewis,-M.R.; Davis,-C.O.; Barber,-R.T.
AF: Dep. Oceanogr., Dalhousie Univ., Halifax, N.S. B3H 4J1, Canada
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C1, pp. 639-654
LA: English
ER: M (Marine)
AB: Macronutrients persist in the surface layer of the equatorial Pacific Ocean because the production of phytoplankton is limited. Measurements of photosynthesis as a function of irradiance (P-I) provide information on the control of primary productivity. P-I was measured in the equatorial Pacific along 150 degree W, during February-March 1988. Diel variability of P-I showed a pattern consistent with nocturnal vertical mixing in the upper 20 m followed by diurnal stratification, causing photoinhibition near the surface at midday. Otherwise, the distribution of photosynthetic parameters with depth and the stability of P-I during simulated in situ incubations over 2 days demonstrated that photoadaptation was nearly complete at the time of sampling: photoadaptation had not been effectively countered by upwelling or vertical mixing. Diel variability of beam attenuation also indicated high specific growth rates of phytoplankton and a strong coupling of production with grazing. It appears that grazing is the proximate control on the standing crop of phytoplankton. Nonetheless, the supply of a trace nutrient such as iron might ultimately regulate productivity by influencing species composition and food-web structure.
AN: 2790870
957 of 1521
TI: Zooplankton contribution to particulate phosphorus and nitrogen in lakes.
AU: Hessen,-D.; Andersen,-T.; Faafeng,-B.
AF: Norwegian Inst. Water Res., P.O. Box 69, Korsvoll, N-0808 Oslo 8, Norway
SO: J.-PLANKTON-RES. 1992. vol. 14, no. 7, pp. 937-947
LA: English
ER: F (Freshwater)
AB: Based on the recognition of rather constant species-specific element to dry weight ratios in freshwater zooplankton, pools of metazoan zooplankton P and N were calculated for 45 Norwegian lakes of varying trophy. On the average zooplankton constituted 20.4 plus or minus 12.3% and 4.6 plus or minus 4.3% of particulate P and N respectively. The fraction was considerably higher in many oligotrophic lakes, at most > 50 and 20% respectively, but declined to similar to 15% (P) and similar to 5% (N) in meso- to eutrophic lakes. In general, phytoplankton contribution to particulate P was < 50%, leaving a large share of particulate P to bacteria and microzooplankton. The zooplankton proportion of particulate P was only weakly influenced by the predation pressure in terms of fish community structure. Zooplankton P is important in the overall lake metabolism, and knowledge of this pool may be used to estimate zooplankton-mediated loss and regeneration of P and improve total nutrient element budgets in lakes.
AN: 2782133
958 of 1521
TI: Grain size effect on anthropogenic trace metal and organic matter distribution in marine sediments.
AU: Krumgalz,-B.S.; Fainshtein,-G.; Cohen,-A.
AF: Natl. Inst. Oceanogr., Israel Oceanogr. and Limnol. Res., Tel-Shikmona, P.O. Box 8030, Haifa 31080, Israel
SO: SCI.-TOTAL-ENVIRON. 1992. vol. 116, no. 1-2, pp. 15-30
LA: English
ER: M (Marine)
AB: The distribution of anthropogenic trace metals (cadmium, copper, iron, lead and zinc) and organic matter was studied in several fractions of marine sediments. Regression analysis of the data using the "dummy variables" approach proved the existence of anthropogenic trace metal and organic matter partitioning on different size fractions of the sediment particles. The sediment fractions 0.125-0.250 mm and 0.063-0.125 mm in most cases possessed similar "fingerprints" of pollutants' distribution.
AN: 2777875
959 of 1521
TI: Changes in plant community structure following liming of an acidified Adirondack lake.
AU: Bukaveckas,-P.A.; Weiher,-E.R.; Boylen,-C.W.
AF: Inst. Ecosyst. Stud., Millbrook, NY 12545, USA
CO: 32. Annu. Meet. of the Aquatic Plant Management Society and Int. Symp. on the Biology and Management of Aquatic Plants, Daytona Beach, FL (USA), 12-16 Jul 1992
SO: ABSTRACTS-OF-THE-AQUATIC-PLANT-MANAGEMENT-SOCIETY,-INC.-THIRTY-SECOND-ANNUAL-MEETING-AND-INTERNATIONAL-SYMPOSIUM-ON-THE-BIOLOGY-AND-MANAGEMENT-OF-AQUATIC-PLANTS. 1992. pp. 17-18
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Woods Lake has been studied since 1984 to investigate the effects of liming on lake trophic interactions and biogeochemical cycles. Aquatic plant communities were surveyed during 2 years prior to liming (1981 and 1984; lake pH < 5) and for 7 years after liming during which lake pH ranged from 5.5 to 6.5 (1985-1991). The most conspicuous effect associated with liming was the decline of the deep-water plants (depth range = 2-5 m). Utricularia purpurea was the dominant deep-water plant and accounted for 75% of total plant coverage in Woods Lake. Within 3 years following liming, Utricularia had declined severely and floating-leaved and canopy-forming species have increased in percent coverage. The most successful of these was Potamogeton epihydrus which was first observed in the lake 3 years after liming. The shift in plant growth forms from deepwater to canopy-forming species is attributed to the decrease in the transparency of the lake as a result of liming.
AN: 2777629
960 of 1521
TI: Measurements of diffusive sublayer thicknesses in the ocean by alabaster dissolution, and their implications for the measurements of benthic fluxes.
AU: Santschi,-P.H.; Anderson,-R.F.; Fleisher,-M.Q.; Bowles,-W.
AF: Dep. Mar. Sci., Texas A&M Univ., Galveston, TX 77843, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1991. vol. 96, no. C6, pp. 10,641-657
LA: English
ER: M (Marine)
AB: Fluxes of reactive chemical species across the sediment-water interface can profoundly influence the dominant biogeochemical cycles in the worlds ocean. However, reliable in-situ measurements of benthic fluxes of many reactive species cannot be carried out without adjustment of stirring rates inside benthic flux chambers to match boundary layer conditions prevailing outside. A simple method to compare flow levels consists of measurements of gypsum dissolution rates inside benthic chambers and on the seafloor. The measurement of the diffusion-controlled dissolution rate of gypsum allows the estimation of the diffusive sublayer thickness and the time-averaged bottom stress on the seafloor. This method had previously been intercalibrated with the stress sensor method in flumes and the inside benthic chambers. We describe here free-vehicle deployments of alabaster plates on the bottom of the ocean which gave results consistent with hydrodynamic theory.
AN: 2772864
961 of 1521
TI: The African rain forest vegetation and palaeoenvironments during Late Quaternary.
AU: Maley,-J.
AF: ORSTROM, UR A3 et CNRS, UA 327, Lab. Palynol., Univ. Sci. Tech. Languedoc, 34095 Montpellier Cedex 5, France
SO: CLIM.-CHANGE. 1991. vol. 19, no. 1-2, pp. 79-98
NT: Special issue: Tropical forests and climate.
LA: English
ER: F (Freshwater)
AB: This review paper presents first the main pollen results on the vegetation history of the rain forest during the late Quaternary. Other palaeoenvironmental data were obtained by diverse geological analyses of the lacustrine sediments. For Bosumtwi, the relatively precise reconstruction of take-level fluctuations permitted several palaeoclimatic interpretations for the main Holocene phases. By comparison with present-day mountain environments, TOC and TON increase in cool environments, but decrease when warmth and humidity increase, as during Holocene time, because the recycling processes speed up in the topsoil. For the same period the alteration of the soils in the catchment produced a strong increase of kaolinite. All these change intervened ca. 9500 yr BP, which is a key date in tropical Africa. In conclusion, climatic correlations between equatorial and dry north tropical Africa illustrate how changes in the forest block must have important effects on adjacent climatic zones.
AN: 2771594
962 of 1521
TI: Carbon sinks in mangroves and their implications to carbon budget of tropical coastal ecosystems.
AU: Twilley,-R.R.; Chen,-R.H.; Hargis,-T.
AF: Dep. Biol., Univ. Southwestern Louisiana, P.O. Box 42451, Lafayette, LA, USA
CO: Int. Workshop on Natural Sinks of CO sub(2), Palmas Del Mar (Puerto Rico), 24-27 Feb 1992
SO: WATER-AIR-SOIL-POLLUT. 1992. vol. 64, no. 1-2, pp. 265-288
NT: Special issue: Natural sinks of CO sub(2).
LA: English
ER: B (Brackish)
AB: Nearly 50% of terrigenous materials delivered to the world's oceans are delivered through just twenty-one major river systems. These river-dominated coastal margins (including estuarine and shelf ecosystems) are thus important both to the regional enhancement of productivity and to the global flux of C that is observed in land-margin ecosystems. The tropical regions of the biosphere are the most biogeochemically active coastal regions and represent potentially important sinks of C in the biosphere. Rates of net primary productivity and biomass accumulation depend on a combination of global factors such as latitude and local factors such as hydrology.
AN: 2766476
963 of 1521
TI: Inorganic nitrogen metabolism in Ulva rigida illuminated with blue light.
AU: Corzo,-A.; Niell,-F.X.
AF: Dep. Ecol., Fac. Sci., Univ. Malaga, Campus Teatinos, E-29071 Malaga, Spain
SO: MAR.-BIOL. 1992. vol. 112, no. 2, pp. 223-228
NT: Bibliogr.: 48 ref.
LA: English
ER: M (Marine)
AB: Inorganic nitrogen metabolism in blue light was studied for the green alga Ulva rigida collected in the south of Spain (Punta Carnero, Algeciras) in the winter of 1987. NH sub(4) super(+) has been reported to inhibit NO sub(3) super(-) uptake; however, U. rigida) showed a net NO sub(3) super(-) uptake even when the NH sub(4) super(+) concentration of the external medium was three or four times greater than the concentration of NO sub(3) super(-). NO sub(3) super(-) uptake rates were similar in both darkness and in blue light of various photon fluence rates (PFR) ranging from 17 to 160 mu mol m super(-2)/s. Since NO sub(3) super(-) uptake is an active mechanism involving the consumption of ATP, respiratory metabolism can provide enough ATP to maintain the energetic requirement of NO sub(3) super(-) transport even in darkness. In contrast, NO sub(3) super(-) reduction in U. rigida) was highly dependent on the net photosynthetic rate. After 7 h in blue light, intracellular NO sub(3) super(-) concentrations ((NO sub(3) super(-)) sub(i)) were higher in specimens exposed to intensities below the light compensation point (LCP) than in those incubated at a PFR above the LCP.
AN: 2764538
964 of 1521
TI: Baseline study on Cd, Cu and Pb concentrations in Atlantic neuston organisms.
AU: Schulz-Baldes,-M.
AF: Alfred-Wegener-Inst. Polar and Mar. Res., D-W 2850 Bremerhaven, FRG
SO: MAR.-BIOL. 1992. vol. 112, no. 2, pp. 211-222
NT: Bibliogr.: 33 ref.
LA: English
ER: M (Marine)
AB: Neuston organisms were caught during 2 Atlantic expeditions (1982 and 1987) between 48 degree N and 40 degree S. About 1200 individuals from 19 taxa were analysed for cadmium, copper and lead. The distribution of metal concentrations was log-normal and thus best described by the median and the percentiles. Fourteen taxa with sample numbers larger than 20 were subjected to a logarithmic regression of weight vs metal concentration. The metal concentrations from populations with significant correlations were then weight-corrected: eight populations for lead, five for cadmium and four for copper. When grouped into ecological categories the pleuston organisms displayed significantly higher cadmium concentrations than the euneuston, which in turn had higher values than the pseudo- and/or facultative neuston. The relative deviation from the median was used in an averaging operation to obtain a broader spatial resolution of the neuston-bound metals, based on 16 taxa which were encountered at 10 or more stations.
AN: 2764521
965 of 1521
TI: Heavy metals in stream sediments: Effects of human activities.
AU: Mantei,-E.J.; Foster,-M.V.
AF: Geosci. Dep., Southwest Missouri State Univ., Springfield, MO, USA
SO: ENVIRON.-GEOL.-WATER-SCI. 1991. vol. 18, no. 2, pp. 95-104
LA: English
ER: F (Freshwater)
AB: The content of 11 heavy metals in the sediments of a stream system was determined by atomic absorption analysis. Geochemical phases were investigated using a sequential extraction scheme, and bulk contents were assessed with a single HNO sub(3) extraction. Certain heavy metals were associated with different geochemical phases. Results from the geochemical phases indicated Cu, Pb, Zn, Cd and Ag were emitted by one landfill, while Cd, Ba, and Ag were emitted by a second landfill. A wastewater treatment facility appeared to emit Ni and Cu. A stream draining a reservoir and joining the study stream resulted in dilution of the heavy metals in the sediments. A populated area along the study stream appeared to emit Mn. The single HNO sub(3) extraction procedure is quicker to perform than the sequential extraction but does not indicate the phase associations.
AN: 2761367
966 of 1521
TI: Investigations into the chemical forms of super(239)Pu in a West Cumbrian saltmarsh soil radiolabelled by an environmental process.
AU: Bulman,-R.A.; Wedgwood,-A.J.; Szabo,-G.
AF: Natl. Radiol. Prot. Board, Chilton, Didcot OX11 0RD, UK
SO: SCI.-TOTAL-ENVIRON. 1992. vol. 114, pp. 215-226
LA: English
ER: M (Marine); B (Brackish)
AB: New procedures have been developed to demonstrate the nature of binding of super(239)Pu in a saltmarsh soil. Evidence is presented which shows that there is a small super(239)Pu component which is present in a form which can be extracted by chelating agents which are similar to naturally occurring chelating agents. By in-situ derivatization procedures it has been possible to isolate two forms of complexed Pu. The effectiveness of humates as sinks for Pu(IV) and Am(III) have been modelled by using some novel forms of humic and fulvic acids chemically immobilized upon silica.
AN: 2761098
967 of 1521
TI: Temporal variations of super(234)Th activity in the water column of Dabob Bay: Particle scavenging.
AU: Wei,-Ching-Ling; Murray,-J.W.
AF: Inst. Oceanol., Natl. Taiwan Univ., P.O. Box 23-13, Taipei, Taiwan
SO: LIMNOL.-OCEANOGR. 1992. vol. 37, no. 2, pp. 296-314
LA: English
ER: M (Marine)
AB: Monthly measurements of total, dissolved, and particulate super(234)Th, along with fluxes of total mass and particulate super(234)Th, were made throughout 1987 in Dabob Bay, Washington. Vertical distributions of total super(234)Th showed a large deficiency relative to super(238)U throughout the water column during all sampling periods. Total super(234)Th activities in surface waters were generally higher in winter and lower in summer, in response to seasonal biological activity. In spite of this variation, the steady state assumption seems valid for modeling super(234)Th of the bay because the magnitude of variation is insignificant in the mass balance calculation. The range of residence times of total, dissolved, and particulate super(234)Th estimated from an irreversible scavenging model are 4-70, <1-10, and 3-60 d, respectively. The residence time of super(234)Th is controlled by the suspended particles whose distribution is determined by biological production in the surface layer and resuspension of bottom sediments.
AN: 2759320
968 of 1521
TI: Importance of benthic productivity in controlling the flux of dissolved inorganic nitrogen through the sediment-water interface in a hypertrophic marine ecosystem.
AU: Krom,-M.D.
AF: Dep. Earth Sci., Leeds Univ., Leeds LS2 9JT, UK
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 78, no. 2, pp. 163-172
LA: English
ER: M (Marine)
AB: The rate of bacterial nitrate reduction measured directly in sediments from a hypertrophic marine ecosystem (6.0 plus or minus 1.5 mmol m super(-2) d super(-1)) was similar to the value calculated from a whole pond nutrient budget (7.7 plus or minus 0.3 mmol m super(-2) d super(-1)) during a phytoplankton crash period. Organic matter breakdown in the sediments represented the dominant source of ammonia-N to the system (16.09 mmol m super(-2) d super(-1) compared to 2.97 mmol m super(-2) d super(-1) directly from fish excretion and 0.28 mmol m super(-2) d super(-1) in the inflow). However most, if not all, of this ammonia-N did not reach the water column as shown by a total nutrient budget for the pond. It was intercepted by the benthic flora and used to support high levels of benthic productivity (246 mmol O m super(-2) d super(-1); 29.72 mmol N m super(-2) d super(-1)). The benthic productivity was calculated by correcting the total system gross production (determined by a total oxygen budget) for water column productivity measured by in situ incubated light/dark bottles.
AN: 2756283
969 of 1521
TI: Sulfate-reducing bacteria in temporarily oxic sediments with bivalves.
AU: Bussmann,-I.; Reichardt,-W.
AF: GEOMAR, Forschungszent. Mar. Geowiss., Wischofstr. 1-3, D-W 2300 Kiel 14, FRG
SO: MAR.-ECOL.-PROG.-SER. vol. 78, no. 1, pp. 97-102
LA: English
ER: M (Marine)
AB: Under seasonally fluctuating redox conditions in sediment of Kiel Bay (eastern Baltic Sea), viable counts (MPN) of sulfate-reducing bacteria (SRB) ranged between 4 x 10 super(2) and 7 x 10 super(4) cm super(-3). These MPN appeared fairly independent of ambient redox potentials and followed peaks of phytoplankton productivity in the water column with a time lag of 2 to 3 wk. The relative proportions of SRB using acetate, lactate or succinate as their electron donors fluctuated widely. Shells of the clam Arctica islandica , which can survive anoxia, were, even in oxic sediments, colonized by epizoic SRB. Significant differences between the abundance of epizoic SRB and SRB from ambient sediment were not detected. In terms of enrichment kinetics, however, epizoic SRB, and particularly those depending on succinate as electron donor, showed quicker responses.
AN: 2756134
970 of 1521
TI: Fluids in convergent margins: What do we know about their composition, origin, role in diagenesis and importance for oceanic chemical fluxes?.
AU: Kastner,-M.; Elderfield,-H.; Martin,-J.B.
AF: Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093-0212, USA
SO: THE-BEHAVIOUR-AND-INFLUENCE-OF-FLUIDS-IN-SUBDUCTION-ZONES:-A-DISCUSSION-HELD-8-9-NOV.-1990. Tarney,-J.;Pickering,-K.T.;Knipe,-R.J.;Dewey,-J.F.-eds. 1991. vol. 335, no. 1638 pp. 243-259
ST: PHILOS.-TRANS.-R.-SOC.-LOND.,-SER.-A. vol. 335, no. 1638
LA: English
ER: M (Marine)
AB: The nature and origin of fluids in convergent margins can be inferred from geochemical and isotopic studies of the venting and pore fluids, and is attempted here for the Barbados Ridge, Nankai Trough and the convergent margin off Peru. Venting and pore fluids with lower than seawater Cl super(-) concentrations characterize all these margins. Fluids have two types of source: internal and external. The three most important internal sources are: porosity reduction; diagenetic and metamorphic dehydration; and the breakdown of hydrous minerals. Gas hydrate formation and dissociation, authigenesis of hydrous minerals and the alteration of volcanic ash and/or the upper oceanic crust lead to a redistribution of the internal fluids and gases in vertical and lateral directions.
AN: 2755375
971 of 1521
TI: Cadmium in the North Sea -- a mass balance.
AU: Kuehn,-W.; Radach,-G.; Kersten,-M.
AF: Inst. Meeresknd., Univ. Hamburg, Troplowitzst. 7, D-2000 Hamburg 54, FRG
SO: J.-MAR.-SYST. 1992. vol. 3, no. 3, pp. 209-224
LA: English
ER: M (Marine)
AB: Based on recently published data on cadmium concentrations in the different compartments of the North Sea ecosystem, i.e. water, suspended particulate matter, biota and sediments, and based on 3D circulation simulations, a (preliminary) mass balance for cadmium in the North Sea was worked out by estimating the contents in the compartments as well as the advective and other fluxes into/out of and within the system. It terns out that the total cadmium content in the water of 810 plus or minus 320 t is in the same order of magnitude as the amount of cadmium in the sediment 1000 plus or minus 500 t. The net deposition flux of cadmium to the sediments (8 t/yr) amounts only to about 3% of the annual anthropogenic input. The amount of cadmium in the biota is about 63 plus or minus 12 t, but the annual turnover of cadmium due to primary production, herbivorous grazing and remineralisation is at least of the same order. The anthropogenic cadmium input from rivers, atmosphere and direct discharges of 310 plus or minus 185 t/yr would add again the total cadmium content in the water in about 2.6 yr. The flushing of the North Sea circulation is very effective: in about 0.7 yr the cadmium contained in the water of the North Sea would be washed out, if no new cadmium would be introduced. The net outflow of cadmium across the northern boundary (307 t/yr) is equal to the anthropogenic input.
AN: 2755365
972 of 1521
TI: Large lakes and their sustainable development.
AU: Tilzer,-M.M.; Bossard,-P.
AF: Limnol. Inst., Univ. Konstanz, Mainaustr. 212, D-7750 Konstanz, FRG
SO: AQUAT.-SCI. 1992. vol. 54, no. 2, pp. 91-103
LA: English
ER: F (Freshwater)
AB: This contribution has been edited from a working document, prepared by invited scientists attending a workshop in Konstanz, Germany, on the importance of external perturbations for short- and long-term changes in large lakes ecosystems, held from 21 to 26 October, 1991. It tries to assess our current understanding of the most important processes involved in the functioning of large lakes and to identify the currently most urgent research priorities in the fields of land-water interactions, physical processes, biogeochemistry and nutrient relations, remote sensing, biological interactions in food webs, and long-term monitoring programs.
AN: 2752969
973 of 1521
TI: Role of the marine biosphere in the global carbon cycle.
AU: Longhurst,-A.R.
AF: Biol. Oceanogr. Div., Bedford Inst. Oceanogr., Dep. Fish. and Oceans, P.O. Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
CO: American Society of Limnology and Oceanography Symp.: What Controls Phytoplankton Production in Nutrient-Rich Areas of the Open Sea?, San Marcos, CA (USA), 22-24 Feb 1991
SO: LIMNOL.-OCEANOGR. 1991. vol. 36, no. 8, pp. 1507-1526
LA: English
ER: M (Marine)
AB: The geochemical disequilibrium of our planet is due mainly to carbon sequestration by marine organisms over geological time. Changes in atmospheric CO sub(2) during interglacial-glacial transitions require biological sequestration of carbon in the oceans. Nutrient-limited export flux from new production in surface waters is the key process in this sequestration. The most common model for export flux ignores potentially important nutrient sources and export mechanisms. Export flux occurs as a result of biological processes whose complexity appears not to be accommodated by the principal classes of simulation models, this being especially true for food webs dominated by single-celled protists whose trophic function is more dispersed than among the multicelled metazoa. The fashionable question concerning a hypothetical "missing sink" for CO sub(2) emissions is unanswerable because of imprecision in our knowledge of critical flux rates. This question also diverts attention from more relevant studies of how the biological pump may be perturbed by climatic consequences of CO sub(2) emissions. Under available scenarios for climate change, such responses may seem more likely to reinforce, rather than mitigate, the rate of increase of atmospheric CO sub(2).
AN: 2752528
974 of 1521
TI: Are the trace metal cycles balanced in the Mediterranean Sea?.
AU: Ruiz-Pino,-D.P.; Jeandel,-C.; Bethoux,-J.-P.; Minster,-J.-F.
AF: LPCM, Quai Darse, 06230-Villefranche sur Mer, France
SO: GLOBAL-PLANET.-CHANGE. 1990. vol. 2, no. 3-4, pp. 369-388
NT: Special Issue: 25 years of physical climatology.
LA: English
ER: M (Marine)
AB: The budgets of Cr, V, Pb, Cd and P have been determined in the Mediterranean Sea. The water flows are described with a 4-box model which distinguishes surface (100 m depth) and deep layers in both western and eastern basins. Trace metal and phosphate concentrations are derived from vertical profiles, established during the PHYCEMED II cruise. The homogeneity of these profiles and the "non-nutrient-like" behavior of Mediterranean trace metal are explained by noticeable external inputs, strong vertical mixing characterizing its hydrology in addition to an unsufficient biological removal. Through the Gibraltar strait, the Mediterranean Sea exports roughly 470, 160 and 330 tons/yr of Cr, Cd and P towards the Atlantic Ocean respectively, whereas 6480 tons/yr of V and 470 tons/y of Pb are imported. The estimations of Total Dissolved Budgets and Deep Waters Budgets show that Mediterranean Cr budget is in deficit whereas V, Pb and Cd ones are in excess. Deep water scavenging/remobilization processes are invoked to equilibrate these budgets. Remobilization of 11-18.10 super(-5) g m super(-2) yr super(-1) of Cr--in agreement with previous results--may explain this element budget. On the other hand, disequilibrated lead Mediterraneran budget can be explained by a non-steady-state situation, which is tested through runs of the 4-box model.
AN: 2748649
975 of 1521
TI: Annual cycle of benthic nutrient fluxes in Tomales Bay, California, and contribution of the benthos to total ecosystem metabolism.
AU: Dollar,-S.J.; Smith,-S.V.; Vink,-S.M.; Obrebski,-S.; Hollibaugh,-J.T.
AF: Hawaii Inst. Mar. Biol., Univ. Hawaii, Honolulu, HI 96822, USA
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 79, no. 1-2, pp. 115-125
NT: Bibliogr.: 28 ref.
LA: English
ER: M (Marine)
AB: Benthic fluxes of dissolved nutrients, oxygen, dissolved inorganic carbon, and total alkalinity were measured over a 2 yr period in Tomales Bay, California, USA, using in situ incubation chambers. Release of dissolved nutrients from the sediment peaked in late summer and was lowest in winter. The difference between C:N:P flux ratios and composition of suspended particulates indicated the existence of a sink for regenerated N, relative to C and P. Total alkalinity flux revealed that carbon metabolism by net sulfate reduction represented ca one-third of total benthic metabolism. Partitioning net system fluxes into component fluxes suggested that the equivalent of ca 70 to 80% of the available particulate C, N and P was respired within the water column, while about 20 to 30% was respired by the benthos. During spring, increasing light resulted in higher water column productivity, followed closely by rising water column respiration. With low delivery of the new organic material to the benthos, and low residual organics in the sediment, benthic respiration remained low.
AN: 2747695
976 of 1521
TI: (Aquatic microbiology in the FRG.).
OT: Stand und Perspektiven der Gewaesser-mikrobiologie in der Bundesrepublik Deutschland
AU: Overbeck,-J.; Rheinheimer,-G.; Gunkel,-W.; Krumbein,-W.E.; Weyland,-H.
AF: Max-Planck-Inst. Limnol., W-2320 Ploen, FRG
SO: NATURWISSENSCHAFTEN. 1991. vol. 78, no. 12, pp. 543-556
LA: German
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Intensive studies on microbial communities in marine and freshwater ecosystems started in the Federal Republic of Germany in the 1960's. It became soon apparent that a real understanding of biogeochemical cycles without consideration of microorganisms is impossible. It was realized that the classical grazing and detritus food chains should be replaced by various microbial loops connecting all trophic levels responsible for the complex food web. Recent approaches apply increasing biochemical and molecular methods for studying the role of microorganisms in aquatic ecosystems.
AN: 2747379
977 of 1521
TI: Vertical profiles of some natural radionuclides over the Alpha Ridge, Arctic Ocean.
AU: Bacon,-M.P.; Huh,-C.-A.; Moore,-R.M.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: EARTH-PLANET.-SCI.-LETT. 1989. vol. 95, no. 1-2, pp. 15-22
LA: English
ER: M (Marine)
AB: Concentration profiles of super(228)Ra, super(234)Th, super(230)Th, super(232)Th, super(228)Th, and super(231)Pa were measured in the CESAR Ice Camp water column (85 degree 50'N, 108 degree 50'W). Thorium isotopes were determined in both dissolved and particulate forms. The results show that rates of scavenging of the reactive nuclides are unusually low, even in comparison with other oligotrophic oceans. Application of a reversible exchange model to the Th isotope data suggests that Th cycling is measurably faster in the surface water than it is at depth.
AN: 2744292
978 of 1521
TI: Nutrient control of phytoplankton photosynthesis in the western North Atlantic.
AU: Platt,-T.; Sathyendranath,-S.; Ulloa,-O.; Harrison,-W.G.; Hoepffner,-N.; Goes,-J.
AF: Biol. Oceanogr. Div., Bedford Inst. Oceanogr., Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
SO: NATURE. 1992. vol. 356, no. 6366, pp. 229-231
LA: English
ER: M (Marine)
AB: The authors report results from several years of oceanographic cruises, showing that the parameters of the photosynthesis-light curve for the flora of the North Sargasso Sea are remarkably constant in magnitude, except during the spring phytoplankton bloom when their magnitudes are noticeably higher. They interpret these results as providing direct evidence for nutrient control of photosynthesis in the open ocean. Our findings also reinforce the plausibility of using biogeochemical provinces to partition the ocean into manageable units for basin- or global-scale analysis, show that seasonal changes in critical parameters should not be overlooked if robust carbon budgets are to be constructed, and illustrate the value of attacking the parameters that control the key fluxes, rather than the fluxes themselves, when investigating the ocean carbon cycle.
AN: 2744136
979 of 1521
TI: Impact of Arenicola marina on bacteria in intertidal sediments.
AU: Grossmann,-S.; Reichardt,-W.
AF: Alfred-Wegener-Inst. Polar- und Meeresforsch., P.O. Box 120161, D-W 2850 Bremerhaven, FRG
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 77, no. 1, pp. 85-93
LA: English
ER: M (Marine)
AB: On intertidal flats of the North Frisian Wadden Sea, total abundance and biomass of bacteria were examined at 6 sites in the particle transport system of Arenicola marina burrows. Both bacterial abundance and biomass showed maxima on the input side, with distinctive peaks in the polychaete's foregut (oesophagus), and declined on the egestive side (hindgut and fecal casts) by 70%. Cell sizes did not differ significantly among sampling sites. In feeding experiments using fluorochrome-labelled (killed) bacteria and indigestible fluorescent particles as a reference standard, disappearance rates of total bacterial biomass were 80 to 90%. Gut extracts showed lysozyme activity. Peaks of bacterial densities in sediment samples from the foregut region that did not appear in the feeding experiments with killed bacteria suggest "gardening". Despite high variances, decreasing viable counts of bacteria on nutrient agar noted between paired foregut and hindgut samples indicated selective survival.
AN: 2744043
980 of 1521
TI: Hydrothermal vent systems.
AU: Tivey,-M.K.
AF: Chem. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: OCEANUS. 1991. vol. 34, no. 4, pp. 68-74
NT: Special issue: Mid-Ocean Ridges.
LA: English
ER: M (Marine)
AB: Hydrothermal systems transfer large amounts of heat and mass from Earth's interior to the oceans. Fluids exiting the chimneys are metal-rich, hot, and acidic, and vent at velocities on the order of meters per second. A striking feature of black smoker chimneys is how remarkably thin their walls are: they vary in thickness from about 5 inches to as little as .25 of an inch. Across this thin layer is a temperature difference of 300 degree C or greater, and similar steep elemental composition gradients also exist. Chimney structures are thus fascinating subjects for scientific study.
AN: 2743929
981 of 1521
TI: Cooperative studies of mid-ocean ridges.
AU: Blackman,-D.; Stroh,-T.
AF: Dep. Geol., Univ. Washington, WA 98105, USA
SO: OCEANUS. 1991. vol. 34, no. 4, pp. 21-23
NT: Special issue: Mid-Ocean Ridges.
LA: English
ER: M (Marine)
AB: The Ridge Inter-Disciplinary Global Experiments (RIDGE) Initiative is a cooperative effort to study the mid-ocean ridges as a dynamic global system of focused energy flow from Earth's interior outward. The National Science Foundation supports the RIDGE Initiative, part of the US Global Change Research Program, through both its Global Change and Ocean Sciences divisions. The program's key goals include: characterizing the global ridge structure; understanding crustal accretion and upper-mantle dynamics; charting the variability over time of volcanic and hydrothermal systems; mapping biological colonization and evolution at ridge crests; determining biological colonization and evolution at ridge crests; determining the properties of multiphase materials at ridge crests; and developing technology for ridge-crest experimentation.
AN: 2743817
982 of 1521
TI: Bacterial number, heterotrophy and extracellular enzyme activity in the Bransfield Strait, Antarctica.
AU: Kim,-S.-J.
AF: Mar. Microbiol. Lab., Korea Ocean Res. and Dev. Inst., Ansan P.O. Box 29, 425-600 Seoul, Rep. Korea
CO: 2. Int. Symp. on Antarctic Science, Seoul (Korea), 17-18 Sep 1990
SO: SECOND-INTERNATIONAL-SYMPOSIUM-ON-ANTARCTIC-SCIENCE. 1991. vol. 2, no. 1 pp. 9-16
ST: KOREAN-J.-POLAR-RES. vol. 2, no. 1
NT: Special Issue.
LA: English
ER: M (Marine)
AB: To study the structure and function of bacterial populations in the Bransfield Strait, Antarctica, which is located between 62 degree similar to 64 degree S and 56 degree similar to 62 degree W, twenty nine sampling stations were chosen. Samples were collected from sea water and sediment during austral summer (Dec. 1989 similar to Jan. 1990) and analyzed for total bacterial number, total saprophytic bacterial number, heterotrophic activity and extracellular enzyme activity. The number of total bacteria in sea water was between 1.0 x 10 super(4) cells/ml and 1.6 x 10 super(5) cells/ml, and total saprophytic bacteria were between 0.5 x 10 super(2) CFU/l and 8.0 x 10 super(4) CFU/l in their numbers. The population density of saprophytic bacteria was significantly low, giving less than 10 super(-4) of the total bacterial number, in this region. Turnover times of glucose and leucine in sea water were in the ranges of 41 and 2094 hrs, and 56 and 980 hrs, respectively. Turnover times of these organic matters were extremely variable depending on the sampling station and water depth.
AN: 2739612
983 of 1521
TI: A fluctuating water-level chamber for biogeochemical experiments in tidal marshes.
AU: Chambers,-R.M.
AF: Tiburon Cent., Box 855, Tiburon, CA 94920, USA
SO: ESTUARIES. 1992. vol. 15, no. 1, pp. 53-58
LA: English
ER: B (Brackish)
AB: An experimental chamber is described which is closed to the water column but encompasses a selected section of the marsh surface. The microcosm is connected to a subsurface collapsible reservoir which functions as a flood water source. Head differences due to tidal fluctuations force reservoir water into and out of the microcosm, so that over complete tidal cycles the net exchanges of materials can be quantified. For this study, seasonal patterns of ammonium and phosphate dynamics in a tidal freshwater marsh were determined using four experimental chambers. On average, phosphate was removed from the water column during the spring, and released to the water column during summer and early fall. Seasonal patterns of ammonium dynamics were less clear, but the marsh removed ammonium from the water column on two of three summer sampling dates. Ammonium and phosphate removal from replicated chambers in vegetated sections of the marsh complex was greater than from unvegetated sections, indicating spatial heterogeneity of nutrient processing. The use of chambers in tidal marshes creates the opportunity to run controlled experiments in situ without imposing artificial hydrologic regimes.
AN: 2737071
984 of 1521
TI: Stable carbon isotope ratios of plankton carbon and sinking organic matter from the Atlantic sector of the Southern Ocean.
AU: Fischer,-G.
AF: Fachber. Geowiss., Univ. Bremen, Klagenfurter Str., D-2800 Bremen 33, FRG
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 581-596
LA: English
ER: M (Marine)
AB: The stable carbon isotope composition of particulate organic carbon (POC) from plankton, sediment trap material and surface sediments from the Atlantic sector of the Southern Ocean were determined. Large variations in the delta super(13)C values of plankton were measured. super(13)C enrichments of up to 10 ppt coincided with a change in the diatom assemblage and a two-fold increase in primary production. This may result in diffusion limitation reducing the magnitude of the isotope fractionation. The delta super(13)C values of plankton from sea-ice cores display a relationship with the chlorophyll a content. In comparison with plankton, sinking krill faeces sampled by traps can be enriched by 2-5 ppt in super(13)C. The transport of particles in other faeces, diatom aggregates or chains results in minor isotope changes. super(13)C enrichments of up to 3-4 ppt may occur at the sediment-water boundary layer. These isotopic changes are attributed to high benthic respiration rates.
AN: 2736114
985 of 1521
TI: Factors controlling the development of phytoplankton blooms in the Antarctic Ocean -- a mathematical model.
AU: Sakshaug,-E.; Slagstad,-D.; Holm-Hansen,-O.
AF: Trondhjem Biol. Stn., Univ. Trondheim, Museum, Bynesveien 46, N-7018 Trondheim, Norway
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 259-271
LA: English
ER: M (Marine)
AB: A mathematical model describing the development of phytoplankton blooms as a function of the depth of the wind-mixed layer, spectral distribution of light, passage of atmospheric low-pressure systems, size of the initial phytoplankton stock and loss rates is presented. Model runs represent shade-adapted, large-celled, bloom-forming diatoms. Periodic deep mixing caused by strong winds may severely retard the development of blooms and frequently abort them before macronutrients are completely exhausted. Complete exhaustion of macronutrients in the upper waters is likely only if the wind-mixed layer is < 10 m deep. Phytoplankton biomass may be controlled by iron in ice-free, deep-sea parts of the Antarctic Ocean, but the implied enhancement of export production through addition of iron might be restricted because of limitation by light, i.e. vertical mixing.
AN: 2735809
986 of 1521
TI: Nutrient distributions and new production in polar regions: Parallels and contrasts between the Arctic and Antarctic.
AU: Smith,-W.O.,Jr.
AF: Bot. Dep. and Grad. Prog. Ecol., Univ. Tennessee, Knoxville, TN 37996, USA
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 245-257
LA: English
ER: M (Marine)
AB: This paper discusses the influences of nitrate and ammonium concentrations on nitrate uptake (and hence new production), particularly with regard to data collected within marginal ice zones in the Arctic and Antarctic. Subsurface ammonium maxima in waters over 150 m are frequently encountered in the Arctic and occasionally in the Antarctic. Such maxima result from the heterotrophic remineralization of organic matter, and because stratified environments occur more frequently in the Arctic, significant concentrations of ammonium accumulate as a result of lower diffusive losses. Bacteria vs. zooplankton may also be different in the Arctic. Elevated ammonium concentrations significantly reduce nitrate uptake, and it is suggested that this nutrient interaction may play a significant role in controlling new production, particularly in open water regions.
AN: 2735791
987 of 1521
TI: delta super(13)C and delta super(15)N Variations in Weddell Sea particulate organic matter.
AU: Rau,-G.H.; Sullivan,-C.W.; Gordon,-L.I.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 355-369
LA: English
ER: M (Marine)
AB: The delta super(13)C and delta super(15)N of particulate organic matter (POM) sampled from the Weddell Sea in 1986 and 1988 ranged from -30.4 to -16.7 ppt and from -5.4 to +41.3 ppt, respectively. These large variations in POM delta super(13)C and delta super(15)N may reflect spatial/temporal changes in the concentrations and isotope abundances of CO sub(2)(aq.) and NH super(+)@)d4, respectively. Elevated isotope values were found exclusively in POM in or closely associated with sea ice, which may be the source of the super(13)C- and super(15)N-enriched sediments observed in this region.
AN: 2735762
988 of 1521
TI: Scavenging and particle flux: Seasonal and regional variations in the Southern Ocean (Atlantic sector).
AU: Rutgers-van-der-Loeff,-M.M.; Berger,-G.W.
AF: Alfred Wegener Inst. Polar and Mar. Res., Columbusst., D-2850 Bremerhaven, FRG
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 553-567
LA: English
ER: M (Marine)
AB: Even with large variations in flux rates, the scavenging of Pb and Th remains closely coupled to particle flux. In the Bransfield Strait, > 95% of the scavenging of super(230)Th and super(210)Pb occurs in two productive months, followed by negligible fluxes in winter. In winter, total super(234)Th reaches equilibrium with its parent super(238)U. During the bloom period, it is rapidly adsorbed onto particles and removed from the surface water. Notwithstanding the short production period, the annual fluxes of super(230)Th and super(210)Pb exceed their respective production rates in the water column by 60%. super(210)Pb inventories in the sediment reflect the distribution of average present-day particle flux: high inventories occur in a zone just south of the Polar Front, including the Bransfield Strait and Drake Passage; low inventories are found north of the Polar Front and in the Weddell Sea, with minimum values in the central Weddell Gyre. A general relationship between radionuclide fluxes and particle rain rates as a tool for hindcasting palaeoproductivities cannot be given.
AN: 2735651
989 of 1521
TI: The production of biogenic silica in the Weddell and Scotia seas.
AU: Queguiner,-B.; Treguer,-P.; Nelson,-D.M.
AF: Lab. Chim. Ecosyst. Mar., Inst. Etud. Mar., Univ. Bretagne Occidentale, F-29287 Brest Cedex, France
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 449-459
LA: English
ER: M (Marine)
AB: During the EPOS leg 2 cruise, the production rate of biogenic silica in the euphotic zone was measured by the super(30)Si method at stations in the Scotia and Weddell Seas. The highest integrated production rates were observed in the Scotia Sea, the marginal ice zone of the Weddell Sea exhibiting somewhat lower values. Results demonstrate that as far as biogenic silica production is concerned the marginal ice zone of the Weddell Sea is considerably less productive than that of the Ross Sea. The results also indicate that the water of the Antarctic Circumpolar Current (ACC) could be more productive in late spring and early summer than at the beginning of spring. Possible reasons for the differences among the three subsystems (Ross Sea, Weddell Sea and ACC) are discussed.
AN: 2735257
990 of 1521
TI: Barite formation in the Southern Ocean water column.
AU: Stroobants,-N.; Dehairs,-F.; Goeyens,-L.; Vanderheijden,-N.; Grieken,-R.-van
AF: Vrije Univ. Brussel, Anal. Chem. (ANCH), Pleinlaan 2, B-1050 Brussels, Belgium
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 411-421
LA: English
ER: M (Marine)
AB: The intensity of past biological activity can be correlated with the occurrence of suspended and sedimented barite (BaSO sub(4)). Vertical profiles of particulate barium generally show a Ba maximum between 200 and 500 m. SEM-EMP investigations on Scotia-Weddell Sea Confluence profiles provide a possible explanation for the origin of this subsurface Ba maximum. In the surface waters (i.e. above 200 m) barite is mainly contained within large bioaggregates. In the first 10-20 m of the water column the barite particles in the bioaggregates appear as amorphous entities without a clear crystalline habit. Below this surface layer barite in bioaggregates is present as microparticles with a crystalline habit. Below the first few hundred meters, barite crystals occur as free discrete particles. This suggests that in the subsurface zone (below 200 m) the "aggregates" are dispersed, possibly as a result of bacterial activity on the organic matrix, thereby releasing the individual barite crystals. Data suggest active precipitation by the living phytoplankton cell (i.e intravacuolar barite formation), as already observed by others for cultures of marine algae (Pavlovales).
AN: 2735163
991 of 1521
TI: Suspended barite as a tracer of biological activity in the Southern Ocean.
AU: Dehairs,-F.; Stroobants,-N.; Goeyens,-L.
AF: Vrije Univ. Brussel, ANCH, Pleinlaan 2, B-1050 Brussels, Belgium
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 399-410
LA: English
ER: M (Marine)
AB: During two cruises in the Southern Ocean (INDIGO 3, Indian sector and EPOS 2, Scotia-Weddell Confluence) suspended matter samples were collected for analysis of several biogenic elements including Ba, Si and particulate organic carbon (POC). The good agreement between particulate barium in subsurface water with oxygen minimum concentrations as well as with nitrate depletions suggests that it reflects the intensity of new production over the past season. As a consequence of new production in the Southern Ocean being performed mainly by diatoms, the occurrences of barite and diatoms are related in the water column. In areas characterized by diatom-poor phytoplankton, barite does occur, but in lower concentrations.
AN: 2735138
992 of 1521
TI: The dynamics of CO sub(2) fixation in the Southern Ocean as indicated by carboxylase activities and organic carbon isotopic ratios.
AU: Fontugne,-M.; Descolas-Gros,-C.; Billy,-G.-de
AF: Cent. Faibles Radioactiv., Lab. Mixte CNRS/CEA, Domaine du CNRS, 91 198 Gif sur Yvette, France
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 371-380
LA: English
ER: M (Marine)
AB: The authors present results from three cruises in the Indian and Atlantic sectors of the Southern Ocean (between 40 and 66 degree S) in which biochemical and physiological factors associated with photosynthetic processes lead to carbon isotopic fractionation by phytoplankton which cannot be directly related to variations within the mineral carbon pool. Simultaneous measurements of the carboxylase activities and the super(13)C/ super(12)C ratio of particulate organic carbon show that there is a large variability in phytoplankton carbon metabolism, especially on a seasonal scale, in spite of a relative uniformity of the environmental conditions. Phytoplankton carbon metabolism is clearly a main factor governing variations in the stable isotopic composition of organic matter in the euphotic layer. Interrelationships between light, Rubisco activity and delta super(13)C are clearly shown. Heterotrophic processes also may influence the carbon isotope mass balance, especially during the break-up of the ice pack. The effect of the meridional temperature gradient is also verified.
AN: 2735095
993 of 1521
TI: Variations in phytoplanktonic nitrogen assimilation around South Georgia and in the Bransfield Strait (Southern Ocean).
AU: Owens,-N.J.P.; Priddle,-J.; Whitehouse,-M.J.
AF: Plymouth Mar. Lab., Prospect Pl., The Hoe, Plymouth PL1 3DH, UK
CO: Int. Symp. on Biochemistry and Circulation of Water Masses in the Southern Ocean, Brest (France), 2-6 Jul 1990
SO: MAR.-CHEM. 1991. vol. 35, no. 1-4, pp. 287-304
LA: English
ER: M (Marine)
AB: Nitrogen assimilation was measured in two austral summers in the Scotia Sea around the island of South Georgia and in the Bransfield Strait. Nitrate and ammonium assimilation was measured using super(15)N techniques and the population was divided into two size classes, less than and greater than 20 mu m. The highest assimilation rate was found at a station near South Georgia, where the chlorophyll standing stock was elevated. A high assimilation rate was observed at a station in the Bransfield Strait and was associated with a localised, shallow mixed-layer feature. The less than 20 mu m size fraction contributed to a variable but frequently significant proportion of the total assimilation (14-78%). f ratios were generally low, signifying a high dependence of the population on ammonium as a nitrogen source.
AN: 2735071
994 of 1521
TI: Reconciling aggregation theory with observed vertical fluxes following phytoplankton blooms.
AU: Hill,-P.S.
AF: Sch. Oceanogr. WB-10, Univ. Washington, Seattle, WA, 98195, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1992. vol. 97, no. C2, pp. 2295-2308
LA: English
ER: M (Marine)
AB: Sediment trap data show that rapidly sinking pulses of phytodetritus form after phytoplankton blooms, even when bloom intensity is low. A numerical model of physical aggregation and sedimentation in the surface ocean was used to gauge whether predicted aggregation rates were high enough to generate postbloom sediment pulses. Initial models behaved inaccurately without a full range of particle sizes, abundant nonphytoplankton particles, and explicit hydrodynamic retardation of particle contact. Provision for background particles while tracking phytoplankton required implementation of a novel bookkeeping scheme. To address the degree of retardation for contact between particles, an expression for contact efficiency for collision by turbulent shear was developed. The most realistic way to produce model results that mimicked field data was to include background particles, to invoke particle stickiness in the range 0.1-1.0, and to make modest upward adjustments to contact efficiencies calculated for impermeable spheres.
AN: 2735040
995 of 1521
TI: Evolution of Pb, Zn, Cu, Ni and As in Arcachon Lagoon (France). Influence of vegetal biomass on the geochemistry of lagoonal environment.
OT: Evolution du Pb, Zn, Cu, Ni et As dans le Bassin d'Arcachon (France). Impact de la biomasse vegetale sur la geochimie d'un environment lagunaire
AU: Lapaquellerie,-Y.; Latouche,-C.; Maillet,-N.; Dumon,-J.-C.; Carruesco,-C.
AF: Cent. Rech. Environ. Sed. Oceaniq., URA 197, Univ. Bordeaux 1, 351 Cours de la Liberation, 33405 Talence, France
SO: J.-MAR.-SYST. 1992. vol. 3, no. 1-2, pp. 19-30
LA: French
ER: M (Marine)
AB: The concentration of metals as Pb, Cu, Ni and As in suspended matters and sediments during 14 years shows for suspended matters and sediments that: Zn and Cu are increasing, Pb and As decreasing and Ni is stabilised. The evolution of the suspended matter can be explained by the quantitative evolution of algae and phanerogams during these last 14 years. The biomass evolution, which resulted in environmental nutrient contribution, intensifies the exchange factors of Pb and As in the lagoon. These remarks, beyond their local interests, provide notions of sedimentary environment model opposed to a polluting environment constituted by nautic tourism and a large area of monoculture (corn).
AN: 2733880
996 of 1521
TI: The relative importance of biotic and abiotic vectors in nutrient transport.
AU: Bildstein,-K.L.; Blood,-E.; Frederick,-P.
AF: Dep. Biol., Winthrop Coll., Rock Hill, SC 29733, USA
SO: ESTUARIES. 1992. vol. 15, no. 2, pp. 147-157
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The mass of nutrients (nitrogen, phosphorus, potassium, and calcium) imported during 1984 and 1985 to the North Inlet Estuary, Georgetown County, South Carolina, by precipitation and runoff was compared with that imported by a colonial-nesting wading bird, the white ibis (Eudocimus albus ). From late March through late June of both years, breeding ibises imported nutrients to the North Inlet Estuary study site from freshwater bottomland forest swamps, where they fed on crayfishes (Procambaridae). Although 1984 was a relatively wet year, in 1985 the ibis breeding season was preceded by a severe winter-spring drought. In 1984 ibises nested in higher numbers, had higher per-pair breeding success, and imported 11 times more nutrients than in 1985. Nutrient input from atmospheric sources was substantially lower in 1984 than in 1985. Our results show that nutrient inputs to estuaries from colonial-nesting wading birds can be substantial when compared with those from atmospheric sources and can vary considerably among years. They also suggest that nutrient regimes in estuaries with large assemblages of wading birds may differ significantly from those lacking such colonies.
AN: 2733555
997 of 1521
TI: Biochemical oxidation of organic matter in Bay of Bengal waters of Madras-Visakhapatnam.
AU: Loganathan,-B.; Venugopalan,-V.K.
AF: Cent. Adv. Stud. Mar. Biol., Annamalai Univ., Porto Novo 608 502, India
SO: INDIAN-J.-MAR.-SCI. 1984. vol. 13, no. 4, pp. 184-186
LA: English
ER: M (Marine)
AB: Water samples from 15 fixed stations in coastal and offshore regions in Bengal Bay were analysed for total non-specific organic matter through biochemical oxygen demand (BOD) analysis. BOD values varied between stations, depending on the nature and amount of organic matter decomposed by heterotrophic bacteria. The velocity rate (K) of destruction of organic matter and the ultimate BOD (L) of I stage were calculated using unimolecular equations. The computed rate constants help to predict the biochemical oxidation process involved and to asses the degree of population and self-purification capacity of polluted waters. K and L values of the station studied are quite comparable to the K and L values of other oceans reported earlier.
AN: 2733203
998 of 1521
TI: Nutrient cycling and fluxes associated with coastal regions adjacent to the Mississippi River.
AU: Twilley,-R.R.
AF: Univ. Southwestern Louisiana, Lafayette, LA 70501, USA
CO: 156. Natl. Meet. of the American Assoc. for the Advancement of Science, New Orleans, LA (USA), 15-20 Feb 1990
SO: 1990-AAAS-ANNUAL-MEETING-ABSTRACTS. Games,-M.D.-comp. 1989. p. 76
NT: Abstract only.
LA: English
ER: F (Freshwater)
AB: Nutrient regeneration will be compared between two distributaries of the Mississippi River that discharge sediment and nutrients to coastal region of Louisiana: the Atchafalaya River empties into shallow bays while Southwest Pass flows into continental shelf. Stations included water depths of 1-2 m in the upper and lower sections of the Bay to 20-80 m on the continental shelf, during periods of high and low river flow. Respiration rates during the spring were similar among all stations at about 1.9 mmols m super(-2) h super(-1). Sediment regeneration rates for ammonium and silicate in both estuaries were generally higher near river input or in regions of highest water column productivity. Nitrate uptake generally occurred during the spring near freshwater; whereas nitrate and nitrite regeneration occurred at rates up to 80 umols m h in more saline environments. Phosphorus regeneration was less than 25 umols at all stations; lower rates occurred with elevated sediment redox. Water column regeneration was highest in areas with high levels of chlorophyll.
AN: 2731798
999 of 1521
TI: Estuarine modulation of nutrient transport from land to sea: Retention, assimilation and export.
AU: Kemp,-W.M.; Malone,-T.C.; Boicourt,-W.C.; Boynton,-W.R.; et-al.
AF: Univ. Maryland, CEES, Cambridge, MD, USA
CO: 156. Natl. Meet. of the American Assoc. for the Advancement of Science, New Orleans, LA (USA), 15-20 Feb 1990
SO: 1990-AAAS-ANNUAL-MEETING-ABSTRACTS. Games,-M.D.-comp. 1989. p. 76
NT: Abstract only.
LA: English
ER: B (Brackish); F (Freshwater)
AB: A hypothesis is developed and supporting evidence is presented to explain how physical and ecological mechanisms can allow estuaries, such as Chesapeake Bay, to retain, utilize and recycle nutrient inputs from the watershed in the short run while eventually exporting them to the sea. Time-series data indicate that planktonic and benthic community processes exhibit clear responses to seasonal and interannual variations in nitrogen inputs (mostly as NO sub(3) super(-)). However, preliminary mass balance calculations and short-term flux calculations at the bay mouth suggest that a large fraction of this N loading is exported to the continental shelf, largely in relatively refractory forms of DON. Thus, while the estuary is non-retentive with respect to N in a quantitative sense, it may nonetheless act as an efficient filter for the qualitative aspects of these N resources.
AN: 2731774
1000 of 1521
TI: Cyanobacterial precipitation of gypsum, calcite, and magnesite from natural alkaline lake water.
AU: Thompson,-J.B.; Ferris,-F.G.
AF: Dep. Microbiol., Univ. Guelph, Guelph, Ont., Canada
SO: GEOLOGY. 1990. vol. 18, no. 10, pp. 995-998
LA: English
ER: F (Freshwater)
AB: Results from transmission electron microscopy provide direct evidence for cyanobacterial biomineralization of gypsum and calcite in aquatic environments. Laboratory simulations using filter-sterilized natural lake water inoculated with Synechococcus sp., isolated from Fayetteville Green Lake, New York, revealed epicellular biomineralization of gypsum, calcite, and magnesite. Experimental, electron microscopical, and sedimentological evidence indicates that Synechococcus is responsible for a major proportion of the marl sediment and carbonate bioherms in Green Lake.
AN: 2731233
1001 of 1521
TI: GEOSECS Pacific and Indian Ocean super(32)Si profiles.
AU: Somayajulu,-B.L.K.; Rengarajan,-R.; Lal,-D.; Craig,-H.
AF: Phys. Res. Lab., Ahmedabad 380 009, India
SO: EARTH-PLANET.-SCI.-LETT. 1991. vol. 107, no. 1, pp. 197-216
LA: English
ER: M (Marine)
AB: Results of measurements of twelve super(32)Si vertical profiles, nine from the Pacific Ocean at latitudes 45 degree N-58 degree S, and three from the Indian Ocean between the Equator and 38 degree S are presented. The amounts of in-situ extracted SiO sub(2) range from similar to 1 to 25 g. The volumes of water from which dissolved silicon was extracted range from 200 to 9 x 10 super(5) kg. The net super(32)P activities range from 0.7 to 3.8 cph. It is possible to measure accurately super(32)Si ( super(32)P) activities as low as 2 x 10 super(-2) dpm from 25 g SiO sub(2) with the present techniques. The super(32)Si concentrations in water range from 0.1 dpm/10 super(6) kg seawater to 178 dpm/10 super(6) kg seawater. The overall pattern of super(32)Si increase with depth in the oceans resembles that of Si but the two differ appreciably; the enrichment of the former is controlled by its relatively short half-life.
AN: 2730049
1002 of 1521
TI: Fluxes of super(226)Ra and barium in the Pacific Ocean: The importance of boundary processes.
AU: Moore,-W.S.; Dymond,-J.
AF: Dep. Geol. Sci., Univ. South Carolina, Columbia, SC 29208, USA
SO: EARTH-PLANET.-SCI.-LETT. 1991. vol. 107, no. 1, pp. 55-68
LA: English
ER: M (Marine)
AB: The super(226)Ra/Ba ratio in particles collected in sediment traps decreases with depth. Fluxes of Ba and Al increase with depth. These observations cannot be explained by simple vertical processes. Instead they require a component to the deep flux which originates at the ocean margins. We suggest that the deep traps are enriched in Ba through the advection of barite originally precipitated in biologically productive regions of the ocean margin. This source is less important for super(226)Ra because some is lost by radioactive decay between the precipitation of barite on the margin and outward transport. The boundary flux is an important source of material to the deep sea. From super(226)Ra fluxes in the upper 1000 m of the water column, we estimate that the residence time of super(226)Ra in the upper ocean is 400 years. The removal of super(226)Ra in the particle flux is approximately balanced by the upwelling of waters enriched in super(226)Ra.
AN: 2729170
1003 of 1521
TI: Evolutionary trends in the lipid biomarker approach for investigating the biogeochemistry of organic matter in the marine environment.
AU: Saliot,-A.; Laureillard,-J.; Scribe,-P.; Sicre,-M.A.; Branica,-M.
AF: Lab. Phys. et Chim. Mar., Univ. Pierre et Marie Curie, UA, CNRS No. 353, 4 place Jussieu, 75252 Paris Cedex 05, France
CO: 11. Int. Symp. on Chemistry of the Mediterranean, Primosten (Croatia), 9-16 May 1990
SO: REACTIVITY-OF-CHEMICAL-SPECIES-IN-AQUATIC-ENVIRONMENTS. Kniewald,-G.-ed. 1991. vol. 36, no. 1-4 pp. 233-248
ST: MAR.-CHEM. vol. 36, no. 1-4
LA: English
ER: M (Marine)
AB: The detailed investigation of organic carbon cycling in estuarine and marine environments has stimulated the development of multidisciplinary concepts, research and sampling strategies as well as analytical tools in the last 10 years. Although some limitations exist for the elucidation of their stereochemistry, sterols have been used extensively to study biochemical processes affecting the organic matter in the water column and at the ocean/sediment interface. Sterols also appear as promising tracers of terrestrial vs. marine inputs in complex estuarine systems. The specificity of individual fatty acids or groups of acids has also been used to assess the origins and transformation processes of organic matter in marine samples. New approaches are presented including the investigation of intact lipid classes and the elucidation of the position of double bonds of unsaturated fatty acids and alkenes. Finally, we discuss the use of chemometric techniques due to increasing chemical information and the interest of combining molecular-level and stable isotope approaches.
AN: 2726662
1004 of 1521
TI: Dissolved trace element cycles in the San Francisco Bay estuary.
AU: Flegal,-A.R.; Smith,-G.J.; Gill,-G.A.; Sanudo-Wilhelmy,-S.; Anderson,-L.C.D.; Branica,-M.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
CO: 11. Int. Symp. on Chemistry of the Mediterranean, Primosten (Croatia), 9-16 May 1990
SO: REACTIVITY-OF-CHEMICAL-SPECIES-IN-AQUATIC-ENVIRONMENTS. Kniewald,-G.-eds. 1991. vol. 36, no. 1-4 pp. 329-363
ST: MAR.-CHEM. vol. 36, no. 1-4
LA: English
ER: B (Brackish)
AB: Dissolved trace element (copper, nickel, cadmium, zinc, cobalt, and iron) concentrations were measured in surface water samples collected from 27 stations in the San Francisco Bay and Sacramento-San Joaquin Delta during Apr., Aug. and Dec. 1989. The trace element distributions were relatively similar for all three sampling periods, and evidenced two distinct biogeochemical regimes within the estuarine system. The two regimens were comprised of relatively typical trace element gradients in the northern reach and anthropogenically perturbed gradients in the southern reach of the estuary. These dichotomous trace element distributions were consistent with previous reports on the distributions of nutrients and some other constituents within the estuary.
AN: 2726611
1005 of 1521
TI: Evolution of dissolved and particulate matter during the ice-covered period in a deep, high-mountain lake.
AU: Catalan,-J.
AF: Dep. Ecol., Univ. Barcelona, Diagonal 645, 08028 Barcelona, Spain
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1992. vol. 49, no. 5, pp. 945-955
NT: Incl. bibliogr.: 60 ref.
LA: English
ER: F (Freshwater)
AB: Changes in inorganic and organic matter beneath the ice in a deep oligotrophic lake are used to establish temporal and spatial scales of physical and biological processes involved in the dynamics of the system during low energy flow.
AN: 2725795
1006 of 1521
TI: Atmospheric cycling and air-water exchange of mercury over mid-continental lacustrine regions.
AU: Fitzgerald,-W.F.; Mason,-R.P.; Vandal,-G.M.
AF: Dep. Mar. Sci., Univ. Connecticut, Groton, CT 06340, USA
CO: Int. Conf. on Mercury as an Environmental Pollutant, Gaevle (Sweden), 11-13 Jun 1990
SO: WATER-AIR-SOIL-POLLUT. 1991. vol. 56, pp. 745-767
LA: English
ER: F (Freshwater)
AB: Atmospheric mobilization and exchange at the air-water interface are significant features of biogeochemical cycling of Hg at the Earth's surface. Our marine studies of Hg have been extended to inland aquatic systems, where we are investigating the tropospheric cycling, deposition and air-water exchange of Hg in the mid-continental lacustrine environs of north central Wisconsin. This program is part of a multidisciplinary examination into the processes regulating the aquatic biogeochemistry of Hg in temperate regions. Trace-metal-free methodologies are employed to determine Hg and and alkylated Hg species at the picomolar level in air, water and precipitation.
AN: 2721576
1007 of 1521
TI: Copper complexes with the porphyrin system in sediments of the Baltic Sea.
AU: Kowalewska,-G.
AF: Inst. Oceanol., Polish Acad. Sci., ul. Powstancow Warszawy 55, 81-967 Sopot, Poland
SO: POL.-ARCH.-HYDROBIOL.-POL.-ARCH.-HYDROBIOL. 1990. vol. 37, no. 3, pp. 327-339
LA: English
ER: M (Marine)
AB: Extracts of bottom sediments from the Baltic Sea were studied for possible occurrence of copper complexes with the porphyrin system. A correlation between copper content and porphyrin-type compounds in HPLC chromatograms of the extracts has been found. Copper content was usually highest in extracts of the surface layer, which indicated contemporary formation and accumulation of the compounds. The observed correlation of the porphyrin compounds with carotenes let us suppose that copper is involved in a biogeochemical cycle, entering the porphyrin ring of chlorophyll and being released in sediments, especially under anoxic conditions.
AN: 2720372
1008 of 1521
TI: Interhemispheric transport of carbon dioxide by ocean circulation.
AU: Broecker,-W.S.; Peng,-Tsung-Hung
AF: Lamont-Doherty Geol. Obs., Columbia Univ., Palisades, NY 10964, USA
SO: NATURE. 1992. vol. 356, no. 6370, pp. 587-589
LA: English
AB: Before the Industrial Revolution, natural CO sub(2) sources and sinks acted to set up a south to north gradient which drove about one gigatonne of carbon each year through the atmosphere from the Southern to the Northern Hemisphere. At steady state, this flux must have been balanced by a counter flow of carbon from north to south through the ocean. Here we present a means to estimate this natural flux by a separation of oceanic carbon anomalies into those created by biogenic processes and those created by CO sub(2) exchange between the ocean and atmosphere. Deep water formed in the northern Atlantic Ocean carried about 0.6 gigatonnes of carbon annually to the Southern Hemisphere, providing support for Keeling and Heimann's proposal. The existence of this oceanic carbon pump also raises questions about the need for a large terrestrial carbon sink in the Northern Hemisphere to balance the present global carbon budget.
AN: 2718697
1009 of 1521
TI: Feeding and assimilation of mangrove leaves by the crab Sesarma meinerti de Man in relation to leaf-litter production in Mgazana, a warm-temperate southern African mangrove swamp.
AU: Emmerson,-W.D.; McGwynne,-L.E.
AF: Dep. Zool., Univ. Transkei, P Bay X1, Umtata, Transkei, South Africa
SO: J.-EXP.-MAR.-BIOL.-ECOL. 1992. vol. 157, no. 1, pp. 41-53
LA: English
ER: M (Marine)
AB: Consumption of Avicennia marina leaves by the large detritivorous mangrove grapsid Sesarma meinerti was measured in the laboratory. This was compared with abscission rates for this mangrove species in the field (Mgazana estuary, Transkei, southern Africa) to estimate how much leaf material was directly utilised by this ecologically dominant crab. Although a significant correlation was found between crab size and dry litter mass ingested per day, no correlation was found between crab size and assimilation efficiency, which was high (82.44%). A seasonal trend in leaf litter fall was discernable with a mean annual rate of 1.79 g m super(-2)/d (653.4 g m super(-2)/y). With a mean crab density of 4 m super(-2) and mean crab size of 40 g, leaf consumption was calculated at 0.78 g m super(-2)/d DM (284.7 g m super(-2)/y or 6462 kJ m super(-2)/y), accounting for 43.58% of the leaf fall. For the entire mangrove area (150 ha) a total of 75 t of frasse (955 kJ m super(-2)/y) enters the estuary per annum. This is a considerable contribution to the detrital pool of the estuary and increases leaf turnover an estimated four-fold.
AN: 2718026
1010 of 1521
TI: Oceanic biogeochemical processes: The importance of biology.
AU: Fowler,-S.
AF: Int. Lab. Mar. Radioact., Monaco, Monaco
CA: Union des Oceanographes de France (France)
CO: 16. Colloq. de l'UOF (Union des Oceanographes de France), Roscoff (France), 7-8 Jun 1990
SO: PROCEEDINGS-OF-THE-16th-SYMPOSIUM-OF-UOF-1st-PART,-ROSCOFF-7-8-JUNE-1990.. ACTES-DU-16e-COLLOQUE-DE-L'-UOF-1ere-PARTIE,-ROSCOFF-7-8-JUIN-1990. 1991. vol. 16, no. 1-2 pp. 5-9
ST: J.-RECH.-OCEANOGR. vol. 16, no. 1-2
LA: English
ER: M (Marine)
AB: Element scavenging and removal, organic compound transformations and biogenic particle regeneration of materials are closely coupled to biological activity particularly in the epipelagic and mesopelagic zones where the bulk of oceanic biomass resides. The dynamics of these processes are further controlled by a variety of intrinsic and environmental factors. Recent evidence indicates that biogenic particles are highly enriched in many elements and compounds and thereby serve as important vectors in effecting the downward vertical flux of elements and their distributions in the water column. Analogous to nutrient regeneration cycles, certain elements and radionuclides incorporated in biogenic aggregates are remineralized as the particles sink and undergo decomposition. In contrast, for many particle-reactive elements, sinking biogenic particles scavenge metals and radionuclides and remove them from the surface layers. Recent evidence from in situ sediment trap studies is presented.
AN: 2717958
1011 of 1521
TI: Characterization of surface-active substances during a semi-field experiment on a phytoplankton bloom.
AU: Plavsic,-M.; Vojvodic,-V.; Cosovic,-B.
AF: Rudjer Boskovic Inst., Cent. Mar. Res. Zagreb, Bijenicka c. 54, 41001 Zagreb, Yugoslavia
SO: ANAL.-CHIM.-ACTA. 1990. vol. 232, no. 1, pp. 131-140
NT: Special issue: Humic and fulvic compounds.
LA: English
ER: M (Marine)
AB: The determination of surface-active substances (SAS) during the evolution of a phytoplankton bloom in a model plankton ecosystem was done by electrochemical methods. The separation and characterization of the organic material present were also done on XAD-8 resin columns. It was found that large amounts of the SAS, predominantly of the humic (fulvic) type, were present from the beginning of the experiment and partly masked the effects of organic substances released by phytoplankton. Although the transformation of the organic matter (consumption and/or excretion) was obvious, no general trend in the amount or type of surface-active matter was observed during the experiment.
AN: 2717849
1012 of 1521
TI: Metal-organic interactions in sea water: An ecosystem experiment.
AU: Mackey,-D.J.; O'-Sullivan,-J.E.
AF: CSIRO Div. Oceanogr., GPO Box 1538, Hobart, Tas. 7001, Australia
SO: ANAL.-CHIM.-ACTA. 1990. vol. 232, no. 1, pp. 161-170
NT: Special issue: Humic and fulvic compounds.
LA: English
ER: M (Marine)
AB: A model plankton ecosystem was used to study the interactions of trace metals and organic compounds over a 10-day period during a phytoplankton bloom. Six bags of 1200-l capacity were filled with coastal sea water. Three bags were spiked with copper (78, 157 and 314 nM) and one with copper (4.57 mu M) plus nitrilotriacetic acid (10 mu M). Organically bound complexes of copper (18% of the total), zinc (7%), nickel (4%) and iron (2%) were isolated by adsorption on Sep-Pak cartridges. The metal-organic complexes, were analysed on a liquid chromatograph interfaced to a multichannel atomic fluorescence detector. Organic complexes of zinc, iron and nickel were formed even in the presence of a large excess of copper.
AN: 2717814
1013 of 1521
TI: Ultrafiltration as a technique for studying metal-humate interactions: Studies with iron and copper.
AU: Ephraim,-J.H.; Marinsky,-J.A.
AF: Dep. Water and Environ. Stud., Linkoeping Univ., S-581 83 Linkoeping, Sweden
SO: ANAL.-CHIM.-ACTA. 1990. vol. 232, no. 1, pp. 171-180
NT: Special issue: Humic and fulvic compounds.
LA: English
ER: F (Freshwater)
AB: An ultrafiltration method was employed to study Fe(II)/Fe(III) and Cu(II) binding by Armadale Horizon fulvic acid. The results of the Fe-fulvate studies indicate the formation of "aggregates" between Fe and the fulvic acid molecule. The reduction of Fe(III) to Fe(II) by fulvic acid is also observed. Results for Cu(II)-fulvate interaction obtained by the ultrafiltration method are consistent with those obtained by the direct in situ ion-selective electrode method. An algorithm developed previously for the prediction of metal ion binding by fulvic acid at different pH and salt concentration levels was tested further by comparing Cu super(2+) ion binding predictions with their measured values.
AN: 2717795
1014 of 1521
TI: Modelling of interrelationships between climate, biosphere, and hydrological cycles.
AU: Mauersberger,-P.
AF: Akad. Wiss. DDR, Inst. Geogr. und Geooekol., Bereich Hydrol., Mueggelseedamm 260, Berlin DDR-1162, FRG
SO: GERLANDS-BEITR.-GEOPHYS. 1990. vol. 99, no. 2, pp. 157-161
LA: English
AB: It is recommended to apply generalized hydrothermodynamics and synergetics in combination with the analysis of historical data and recent observations for the investigation and modelling of interrelationships between climate, biosphere and hydrological cycles.
AN: 2716558
1015 of 1521
TI: Iodine abundances in oceanic basalts: Implications for Earth dynamics.
AU: Deruelle,-B.; Dreibus,-G.; Jambon,-A.
AF: Lab. Magmatol. Geochim. Inorgan. Exp., Unit Pierre et Marie Curie, 4 Place Jussieu, F-75252 Paris Cedex 05, France
SO: EARTH-PLANET.-SCI.-LETT. 1992. vol. 108, no. 4, pp. 217-227
LA: English
ER: M (Marine)
AN: 2713812
1016 of 1521
TI: Chitin biomass and production in the marine environment.
AU: Jeuniaux,-C.; Voss-Foucart,-M.F.
AF: Lab. Morphol., Syst. and Anim. Ecol., Univ. Liege, 22 quai Van Beneden, B-4020 Liege, Belgium
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 347-356
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The total production of chitin has been tentatively calculated on the basis of original analytical data on chitin in zooplankton and in benthic communities growing on experimental substrates studied in the Mediterranean Sea, together with data in the literature dealing with total and exuviae production by krill and by some large crustacean species. It appears that crustaceans are the main chitin producers both in planktonic and benthic ecosystems, and that mean total production of chitin in the whole marine biocycle is at least of 2.3 million metric tons per year.
AN: 2712994
1017 of 1521
TI: Mineralization of chitin in an estuarine sediment: The importance of the chitosan pathway.
AU: Gooday,-G.W.; Prosser,-J.I.; Hillman,-K.; Cross,-M.G.
AF: Dep. Mol. and Cell Biol., Univ. Aberdeen, Marischal Coll., Aberdeen AB9 1AS, UK
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 395-400
LA: English
ER: B (Brackish)
AB: In order to study the mineralization of chitinous material, pieces of squid pen chitin-protein in litter bags were exposed to a range of aquatic environments. Scanning electron microscopy showed that they were rapidly colonized by a wide variety of microbes. Populations within microhabitats, however, had a low species diversity, suggesting that cells colonizing initially could rapidly establish colonies. The squid pen was digested in all environments studied, but at rates that varied with season and habitat. Analyses of estuarine sediments of the River Ythan, Aberdeenshire showed appreciable levels of chitin and chitosan, and appreciable activities of chitinase and chitin deacetylase. These results suggest that two pathways are important in the mineralization of chitin in these sediments; one involving chitinases and N-acetylglucosamine, and another involving chitin deacetylase and chitosanase.
AN: 2712993
1018 of 1521
TI: Chitin dynamics in the freshwater environment.
AU: Miyamoto,-S.; Yamamoto,-H.; Seki,-H.
AF: Inst. Biol. Sci., Univ. Tsukuba, Tsukuba, Ibaraki 305, Japan
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 371-377
LA: English
ER: F (Freshwater)
AB: The seasonal fluctuation of chitin dynamics in fresh water was studied in a mesotrophic bog and a hypereutrophic lake in Japan. The metabolic rates of chitin were higher in more eutrophic water. Thus, the chitin turnover rate during summer was one order of magnitude greater in the hypereutrophic lake than in the mesotrophic bog. However, the steady-state oscillation of basal chitin stock averaged approximately 200 mg C/m super(2) in both ecosystems. The production rate of detrital chitin was higher than the decomposition rate in the mesotrophic bog.
AN: 2712977
1019 of 1521
TI: Chitin primary production.
AU: Smucker,-R.A.
AF: EPAC, P.O. Box 1269, Solomons, MD 20688, USA
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 357-369
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Previous perspectives of chitin's role in the biosphere have been deficient because the role of chitin in primary production has been overlooked. Reasons for this oversight include confusion of chitins with the putative protein precipitates forming upon 5% trichloroacetic acid treatment. The cellular biology of known phytoplankton chitin-producers is presented within the context of documented biochemistry and ultrastructure. Several biochemical strategies were used in substantiating the presence of chitin in primary products in in situ experiments. Alkali and sodium dodecylbenzenesulfonate solubilized proteins differentiate protein and chitin. The high values of chitin disclosed for primary production will require rethinking of analytical strategies previously used for biogeochemistry and physiological ecology especially with respect to carbohydrates. Primary production of chitin and chitan must now be considered within the phytoplankton taxa.
AN: 2712975
1020 of 1521
TI: Chitin biodegradation in marine environments: An experimental approach.
AU: Poulicek,-M.; Jeuniaux,-C.
AF: Zool. Inst., Liege Univ., 22 Quai Ed. van Beneden, B-4020 Liege, Belgium
SO: BIOCHEM.-SYST.-ECOL. 1991. vol. 19, no. 5, pp. 385-394
LA: English
ER: M (Marine)
AB: Chitin biomasses and production in marine environments are quite high. Planktonic biocenoses are the main producers and one should expect that sediments, mainly organoclastic ones, will constitute some kind of reserve compartment for the biogeochemical cycle of this polymer. In fact, this is not the case. The low chitin biomass in most marine sediments can only be explained if chitin is weathered at the same rate as it is produced. In order to test this hypothesis, we developed an experimental approach to chitin biodegradation in marine environments. In open water conditions, zooplanktonic remains are first degraded by autolytic processes making most organic compounds readily susceptible for further hydrolysis by extrinsic decomposers. Different populations (with high densities and various hydrolytic potentials) follow each other. The sequence of hydrolytic activities optimizes the recycling of most detritic compounds including nearly 90% of the chitin produced.
AN: 2712952
1021 of 1521
TI: Geology and environmental change: A New Brunswick perspective.
AU: Pronk,-A.G.
AF: Geol. Surv. Branch, Min. Res. Div., Dep. Nat. Resour. Energy, P.O. Box 6000, Fredericton, N.B. E3B 5H1, Canada
SO: ATL.-GEOL. 1991. vol. 27, no. 2, pp. 97-106
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Studies of earth cycles are used in a variety of ways, from mineral exploration to recording and explaining past, and projecting future climate change. Geology helps us find the commodities we need to accommodate our lifestyles, to assess natural hazards, find drinking water and safe places to dispose of our waste. As mankind will search for a way to achieve a globally sustainable society, the limits of this planet will have to be acknowledged. Geology is one of the disciplines that can help us understand our planet and establish those limits. Further research in the earth sciences is required to clarify our present knowledge of the environment, quantify many processes, and define limits of prediction for future change.
AN: 2706084
1022 of 1521
TI: Crystal assembly and phologenetic evolution in heterococcoliths.
AU: Young,-J.R.; Didymus,-J.M.; Bown,-P.R.; Prins,-B.; Mann,-S.
AF: Palaeontol. Dep., Nat. Hist. Mus., Cromwell Rd., London SW7 5BD, UK
SO: NATURE. 1992. vol. 356, no. 6369, pp. 516-518
LA: English
ER: M (Marine)
AB: Coccoliths, the calcite plates formed by unicellular phytoplanktonic algae (coccolithophores, phylum Prymnesiophyta), are produced in enormous quantities and probably constitute the largest single carbonate sink in oceanic biogeochemical cycles. They are major sediment formers, are of great value to geologists as biostratigraphic indicators and have been extensively studied as models for biomineralization. We have applied the understanding of coccolith biomineralization to the fossil record and present evidence from electron and optical microscopy that there has been a conserved mechanism of crystal nucleation throughout the 230 million year history of coccolithophores. This fundamental feature of coccolith growth, which we term the V/R model, involves the assembly of a ring of single crystals with alternating orientations, radial (R) and vertical (V), and provides a powerful tool for tracing phylogenies, identifying homologous structures and rationalizing the higher taxonomy of the group. The living coccolithophorid, Emiliania huxleyi , seemed anomalous because only R crystals had been observed; transmission electron microscopy of proto-coccolith rings, however, evealed relict V crystals which are overgrown by preferential development of R units in complete coccoliths.
AN: 2704008
1023 of 1521
TI: Benthic organic carbon degradation and biogenic silica dissolution in the central Equatorial Pacific.
AU: Martin,-W.R.; Bender,-M.; Leinen,-M.; Orchardo,-J.
AF: Dep. Chem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1991. vol. 38, no. 12A, pp. 1481-1516
LA: English
ER: M (Marine)
AB: Shipboard whole-core squeezing was used to measure pore water concentration vs depth profiles of NO super(-)@)d3, O sub(2) and SiO sub(2) at 12 stations in the equatorial Pacific along a transect from 15 degree S to 11 degree N at 135 degree W. The NO super(-)@)d3 and SiO sub(2) profiles were combined with fine-scale resistivity and porosity measurements to calculate benthic fluxes. After using O sub(2) profiles, coupled with the NO super(-)@)d3 profiles, to constrain the C:N of the degrading organic matter, the NO super(-)@)d3 fluxes were converted to benthic organic carbon degradation rates. The range in benthic organic carbon degradation rates is 7-30 mu mol cm super(-2)/y, with maximum values at the equator and minimum values at the southern end of the transect. The zonal trend of benthic degradation rates, with its equatorial maximum and with elevated values skewed to the north of the equator, is similar to the pattern of primary production observed in the region. Benthic organic carbon degradation is 1-2% of primary production. The range of benthic biogenic silica dissolution rates is 6.9-20 mu mol cm super(-2)/y, representing 2.5-5% of silicon fixation in the surface ocean of the region.
AN: 2702725
1024 of 1521
TI: The contribution of deep-sea macroplankton to organic remineralization: Results from sediment trap and zooplankton studies over the Madeira Abyssal Plain.
AU: Lampitt,-R.S.
AF: Inst. Oceanogr. Sci., Deacon Lab., Wormley, Godalming, Surrey GU8 5UB, UK
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1992. vol. 39, no. 2A, pp. 221-233
LA: English
ER: M (Marine)
AB: At a subtropical deep-sea site of water depth 5440 m the flux of material entering and leaving a 900 m thick stratum 100 m above the seabed was measured using sediment traps. Differences between the organic carbon entering the stratum and that leaving was taken as a measure of the remineralization rate within it. At the same site the biomass of the net zooplankton was measured, and using published estimates of their respiratory requirements, their organic carbon demands were calculated. The results indicate that the zooplankton were responsible for about 9% of the remineralization occurring in that body of water but possibly much higher further up in the water column. The remainder is presumably carried out by those organisms too small, too fragile or too agile to be captured by the net. Although the zooplankton may not contribute greatly to organic carbon remineralization, they are likely to modify sinking and suspended particles in such a way as to have a significant effect on material flux.
AN: 2700982
1025 of 1521
TI: The distribution of dissolved vanadium in eastern Canadian coastal waters.
AU: Yeats,-P.A.
AF: Phys. and Chem. Sci., Dep. Fish. and Oceans, Bedford Inst. Oceanogr., P.O. Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
SO: ESTUAR.-COAST.-SHELF-SCI. 1992. vol. 34, no. 1, pp. 85-93
LA: English
AB: Dissolved vanadium measurements from the Gulf of St Lawrence and the Scotian shelf are reported. The Gulf of St Lawrence results reveal an average vanadium concentration of 24 nM in the deep water of the Gulf decreasing to 17 multiplied by 6 nM in the St Lawrence River. The Saguenay River had an even lower vanadium concentration of 5 multiplied by 1 nM. Linear increases in concentration with salinity were seen for both the St Lawrence estuary and the Saguenay fjord. In the Gulf of St Lawrence and on the Scotian shelf, depletion of vanadium in the surface waters and increasing concentrations with depth were observed. The vanadium-salinity relationships for these coastal waters both show increasing vanadium concentrations with increasing salinity and correlations that are indicative of extensive removal of dissolved vanadium from surface waters. In general, the distributions can be explained in terms of the strengths of the input functions, be they rivers, atmospheric precipitation or oceanic advection, and the removal by biogenic scavenging processes.
AN: 2699680
1026 of 1521
TI: Oceanic uptake of fossil fuel CO sub(2): Carbon-13 evidence.
AU: Quay,-P.D.; Tilbrook,-B.; Wong,-C.S.
AF: Sch. Oceanogr., Univ. Washington, Seattle, WA 98195, USA
SO: SCIENCE-WASH.. 1992. vol. 256, no. 5053, pp. 74-79
LA: English
ER: M (Marine)
AB: The delta super(13)C value of the dissolved inorganic carbon in the surface waters of the Pacific Ocean has decreased by about 0.4 per mil between 1970 and 1990. This decrease has resulted from the uptake of atmospheric CO sub(2) derived from fossil fuel combustion and deforestation. The net amounts of CO sub(2) taken up by the oceans and released from the biosphere between 1970 and 1990 have been determined from the changes in three measured values: the concentration of atmospheric CO sub(2), the delta super(13)C of atmospheric CO sub(2) and the delta super(13)C value of dissolved inorganic carbon in the ocean. The calculated average net oceanic CO sub(2) uptake is 2.1 gigatons of carbon per year. This amount implies that the ocean is the dominant net sink for anthropogenically produced CO sub(2) and that there has been no significant net CO sub(2) released from the biosphere during the last 20 years.
AN: 2698929
1027 of 1521
TI: Variations in the strontium isotopic composition of seawater during the Neogene.
AU: Hodell,-D.A.; Mueller,-P.A.; Garrido,-J.R.
AF: Dep. Geol., Univ. Florida, Gainesville, FL 32611, USA
SO: GEOLOGY. 1991. vol. 19, no. 1, pp. 24-27
LA: English
ER: M (Marine)
AB: The authors report 261 strontium isotopic analyses of well-preserved planktonic foraminifers from three Deep Sea Drilling Project Sites (519, 588, and 607). These samples cover the period from 24 Ma to present with an average of approximately one sample per 100 ka. The combination of high sample density and uniformity of analytical procedures has produced a well-defined record of changes in the super(87)Sr/ super(86)Sr of seawater during the Neogene. The record can be viewed as a series of essentially linear segments with slopes ranging from as high as 6 x 10 super(-5)/m.y. to as low as 0/m.y. The times associated with major inflections in the curve do not appear to correspond to simple geologic phenomena such as eustatic cycles, but are probably controlled by a combination of tectonic and climatic factors that influenced the abundance and isotopic composition of terrestrial strontium input to the oceans. The strontium isotopic data are consistent with a progressive increase in the chemical weathering rates of the continents during the Neogene, probably related to repeated glaciations, increased exposure of continents by lowered sea level, and increased continental relief resulting from high rates of tectonic uplift.
AN: 2698565
1028 of 1521
TI: Revised budget for the oceanic uptake of anthropogenic carbon dioxide.
AU: Sarmiento,-J.L.; Sundquist,-E.T.
AF: Atmos. and Oceanic Sci. Program, Princeton Univ., Princeton, NJ 08544-0710, USA
SO: NATURE. 1992. vol. 356, no. 6370, pp. 589-593
LA: English
ER: M (Marine)
AB: Tracer-calibrated models of the total uptake of anthropogenic CO sub(2) by the world's oceans give estimates of about 2 gigatonnes carbon per year, significantly larger than a recent estimate of 0.3-0.8 Gt C/yr for the synoptic air-to-sea CO sub(2) influx. Although both estimates require that the global CO sub(2) budget must be balanced by a large unknown terrestrial sink, the latter estimate implies a much larger terrestrial sink, and challenges the ocean model calculations on which previous CO sub(2) budgets were based. The discrepancy is due in part to the net flux of carbon to the ocean by rivers and rain, which must be added to the synoptic air-to-sea CO sub(2) flux to obtain the total oceanic uptake of anthropogenic CO sub(2). Here we estimate the magnitude of this correction and of several other recently proposed adjustments to the synoptic air-sea CO sub(2) exchange. These combined adjustments minimize the apparent inconsistency, and restore estimates of the terrestrial sink to values implied by the modelled oceanic uptake.
AN: 2698558
1029 of 1521
TI: Measurement of marine picoplankton cell size by using a cooled, charge-coupled device camera with image-analyzed fluorescence microscopy.
AU: Viles,-C.L.; Sieracki,-M.E.
AF: Bigelow Lab. Ocean Sci., McKown Point, West Boothbay Harbor, ME 04575, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1992. vol. 58, no. 2, pp. 584-592
LA: English
ER: M (Marine)
AB: Accurate measurement of the biomass and size distribution of picoplankton cells (0.2 to 2.0 mu m) is paramount in characterizing their contribution to the oceanic food web and global biogeochemical cycling. Image-analyzed fluorescence microscopy, usually based on video camera technology, allows detailed measurements of individual cells to be taken. The application of an imaging system employing a cooled, slow-scan charge-coupled device (CCD) camera to automated counting and sizing of individual picoplankton cells from natural marine samples is described. A slow-scan CCD-based camera was compared to a video camera and was superior for detecting and sizing very small, dim particles such as fluorochrome-stained bacteria. Several edge detection methods for accurately measuring picoplankton cells were evaluated. Standard fluorescent microspheres and a Sargasso Sea surface water picoplankton population were used in the evaluation.
AN: 2697721
1030 of 1521
TI: Degradation of plant litter by aquatic hyphomycetes.
AU: Hasija,-S.K.; Singhal,-P.K.
AF: Dep. Biol. Sci., Rani Durgavati Univ., Jabalpur, India
SO: HANDBOOK-OF-APPLIED-MYCOLOGY.-SOIL-AND-PLANTS. Arora,-D.K.;Rai,-B.;Mukerji,-K.G.;Knudsen,-G.R.-eds. 1991. vol. 1, pp. 481-505
LA: English
AB: The present review discusses the mode of fungal transformation of litter into an important energy source for the detritus food chain in freshwater environments.
AN: 2697540
1031 of 1521
TI: Naturally and anthropogenically produced bromoform in the Kattegatt, a semi-enclosed oceanic basin.
AU: Fogelqvist,-E.; Krysell,-M.
AF: Swed. Meteorol. Hydrol. Inst., Oceanogr. Lab., P.O. Box 2212, S-403 14 Goeteborg, Sweden
SO: J.-ATMOS.-CHEM. 1991. vol. 13, no. 4, pp. 315-324
LA: English
ER: M (Marine)
AB: The origin of bromoform in seawater and atmosphere, as well as possible sinks and breakdown mechanisms, is discussed. A bromoform budget is calculated for the Kattegatt area between Sweden and Denmark, where the input of bromoform from a power plant is significant. Both anthropogenically (250 x 10 super(6) g yr super(-1)) and biogenically (350 x 10 super(6) g yr super(-1), 0.016 g m super(-2) yr super(-1)) produced bromoform is likely to have a great impact locally on the inventory and the release to the atmosphere. Using measured surface concentrations of bromoform, the total annual release from the Kattegatt to the atmosphere is estimated to 550 x 10 super(6) g (0.025 g m super(-2) yr super(-1)).
AN: 2696732
1032 of 1521
TI: Elemental cycling and fluxes off Southern California.
AU: Muench,-R.D.
AF: SAIC, 13400B Northrup Way, Suite 36, Bellevue, WA 98005, USA
SO: EOS.-TRANS.-AM.-GEOPHYS.-UNION. 1989. vol. 70, no. 10, pp. 146-148
LA: English
ER: M (Marine)
AN: 2695849
1033 of 1521
TI: N sub(2)O concentrations in the water and gas phase of the tidal Elbe and the German Bight.
OT: N sub(2)O-Gehalte in Wasser- und Luftproben aus den Bereichen der Tideelbe und der Deutschen Bucht
AU: Hanke,-V.-R.; Knauth,-H.-D.
AF: GKSS-Forschungszentr. Geesthacht, Max-Planck-Str., D-W 2054 Geesthacht, FRG
SO: VOM-WASSER. 1990. vol. 75, pp. 357-374
NT: Bibliogr.: 22 ref. Received Feb 1992.
LA: German
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Measurements of the distribution of N sub(2)O and to a lesser degree NH sub(4)@)u+, NO sub(3)@)u- and NO sub(2)@)u- in the river Elbe and the German Bight were carried out by analysis of samples from the gas and water phases. The aim of this work was to acquire additional information on the biogeochemistry of the nitrogen cycle in the riverine system. For the determination of N sub(2)O, a suitable method of analysis had to be developed. The results obtained show that the Elbe sediments are an effective source of N sub(2)O. The supersaturation factors for N sub(2)O in the water phase and local concentration increases of the N sub(2)O in the gas phase, when compared to the mean atmospheric value of 330 nl/l, indicate that most of the N sub(2)O gas produced by nitrification and in particular denitrification processes in the Elbe estuarine system is released into the atmosphere.
AN: 2693211
1034 of 1521
TI: Decomposition of dissolved DMSP and DMS in estuarine waters: Dependence on temperature and substrate concentration.
AU: Kiene,-R.P.; Service,-S.K.
AF: Univ. Georgia Mar. Inst., Sapelo Island, GA 31327, USA
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 76, no. 1, pp. 1-11
NT: Bibliogr.: 42 ref.
LA: English
ER: M (Marine)
AB: Dimethylsulfide (DMS) is an important trace gas which is emitted from seawater to the atmosphere. DMS is believed to be derived primarily from the plant osmolyte 3-(dimethylsulfonium)-propionate (DMSP). This study examined the decomposition of dissolved DMSP (DMSP sub(diss)), the production of DMS from DMSP sub(diss), and the consumption of DMS in estuarine waters near Sapelo Island, Georgia, USA. Rate of DMSP sub(diss) disappearance from seawater was directly proportional to the concentration of DMSP sub(diss), over the range of concentrations tested (20 to 100 nM), and was a function of temperature; rates were very low at 4 degree C and increased progressively at 16, 23 and 30 degree C. At 49 degree C the rate of DMSP sub(diss) metabolism was substantially lower. The production of DMS from DMSP sub(diss) displayed similar concentration and temperature dependence. A mass balance of total DMSP during dark incubations indicated that < 30% of the DMSP consumed during the experiments was converted to DMS, even when chloroform (500 mu M) was included to prevent DMS consumption.
AN: 2692888
1035 of 1521
TI: Removal of total phosphorus and phosphate by peat soils of the Florida Everglades.
AU: Jones,-R.D.; Amador,-J.A.
AF: Dep. Biol. Sci., Florida International Univ., Miami, FL 33199, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1992. vol. 49, no. 3, pp. 577-583
LA: English
ER: F (Freshwater)
AB: Traditional estimates of soil and sediment phosphorus retention are based on orthophosphate (PO sub(4)) removal from water by soil or sediment columns under saturated water flow. These techniques may not reflect the P uptake of in situ soils accurately because the PO sub(4) concentration of through-flowing water is often below detection limits in nonpolluted wetlands during the growing season. We used peat soils from the Florida Everglades in saturated flow and equilibrium sorption experiments to show that the uptake of PO sub(4) reaches saturation quickly, potentially underestimating soil P binding capacity when compared with total phosphorus (TP) retention. Removal of TP by these soils appears to involve abiotic mechanisms that include both hydrophobic and ionic interactions.
AN: 2692405
1036 of 1521
TI: Cycling of some trace elements in Lake Constance.
OT: Stoffkreislaeufe ausgewaehlter Spurenelemente im Bodensee
AU: Stabel,-H.-H.; Kleiner,-J.; Merkel,-P.; Sinemus,-H.W.
AF: Betriebs-Forschungslab., ZV Bodenseewasserversorgung, D-W 7770 Ueberlingen-Suessenmuehle, FRG
SO: VOM-WASSER. 1991. vol. 76, pp. 73-91
NT: Bibliogr.: 34 ref.
LA: German
ER: F (Freshwater)
AB: The concentration of several trace elements was recorded weekly in 1986 and 1987 from 20 depths of lake Constance/Ueberlinger See, using atomic absorption spectrometry (AAS). Typical concentrations in mol/l were 4.4-5.3 multiplied by 10 super(-6) for strontium, 0.4-7.7 multiplied by 10 super(-7) for iron, 1.1-8 multiplied by 10 super(-8) for zinc, 3-6 multiplied by 10 super(-9) for chromium, and around 1 multiplied by 10 super(-11) for mercury. Contents of cobalt, lead, silver vanadium, and cadmium were below the detection limits of our methods. The cycling of trace elements in Lake Constance is controlled by the following mechanisms: Autochthonous precipitation of calcite decreases the epilimnetic concentration of strontium and barium, whereas variations in the concentrations of arsenic are due to biological uptake and adsorption to suspended clay. Aluminum, iron, and manganese occur mainly in particulate matter.
AN: 2692401
1037 of 1521
TI: Pathways and microbiology of thiosulfate transformations and sulfate reduction in a marine sediment (Kattegat, Denmark).
AU: Joergensen,-B.B.; Bak,-F.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C., Denmark
SO: APPL.-ENVIRON.-MICROBIOL. 1991. vol. 57, no. 3, pp. 847-856
LA: English
ER: M (Marine)
AB: Reductive and oxidative pathways of the sulfur cycle were studied in a marine sediment by parallel radiotracer experiments with super(35)SO sub(4) super(2-), H sub(2) super(35)S, and super(35)S sub(2)O sub(3) super(2-) injected into undisturbed sediment cores. The distributions of viable populations of sulfate- and thiosulfate-reducing bacteria and of thiosulfate-disproportionating bacteria were concurrently determined. Thiosulfate was concurrently oxidized to sulfate, reduced to sulfide, and disproportionated to sulfate and sulfide. There was a gradual shift from predominance of oxidation toward predominance of reduction with depth in the sediment. Disproportionation was the most important pathway overall. Thiosulfate disproportionation occurred only as cometabolism in the marine acetate-utilizing sulfate-reducing bacteria, which could not conserve energy for growth from this process alone. Oxidative and reductive cycling of sulfur thus occurred in all sediment layers with an intermediate "thiosulfate shunt" as an important mechanism regulating the electron flow.
AN: 2691391
1038 of 1521
TI: The influence of a changing bacterial community on trace metal scavenging in a deep-sea particle plume.
AU: Cowen,-J.P.; Li,-Yuan-Hui
AF: Dep. Oceanogr., Sch. Ocean and Earth Sci. and Technol., Univ. Hawaii at Manoa, Honolulu, HI 96822, USA
SO: J.-MAR.-RES. 1991. vol. 49, no. 3, pp. 517-542
LA: English
ER: M (Marine)
AB: An extensive set of particle samples was collected from the extended (nonbuoyant) hydrothermal plume, the distal remnant plume, and the adjacent waters in a transect across the Southern Juan de Fuca Ridge. Bacterial capsules comprised the primary species of particulate Mn. However, the data also showed significant shifts in the relative abundance of distinctive subpopulations of this bacterial community, as expressed by several consistently recurring capsule morphologies. The data are discussed with respect to distance from plume origins (relative plume age), total bacterial numbers, experimentally determined scavenging rate constants and total particulate and dissolved Mn. The geochemical cycle of Mn in an evolving hydrothermal vent plume is reflected in the distribution coefficients for Mn (K sub(D)), which increase with distance from vent origins. The potential influence that changing subpopulations of bacteria may exert on the overall scavenging behavior of Mn in this evolving natural particle population is emphasized.
AN: 2676998
1039 of 1521
TI: Protozoan plankton ecology.
AU: Laybourn-Parry,-J.
SO: NEW-YORK,-NY-USA-CHAPMAN-AND-HALL 1992. 231 pp
NT: Price: $99.00 (USA), $125.00 (Canada).
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: This text looks at the biology, temporal and spatial distribution patterns and the functional role of planktonic protozoa in fresh, brackish and marine waters. In recent years the importance of these organisms in ecological processes such as the flow of energy and the biogeochemical cycling of carbon, nitrogen and phosphorus in planktonic systems has become widely appreciated. While there are many books covering various planktonic biota, there is no text specifically on the planktonic protozoa. This book therefore provides aquatic biologists with a concise test on this group of organisms written by an acknowledged expert actively engaged in researching planktonic microbial processes. The chapters discuss the planktonic environment, planktonic protozoa and their ecology, important aspects of protozoan physiology, distribution and occurrence of lake protozooplankton, distribution and occurrence of marine and estuarine protozooplankton, and the functional role or protozooplankton.
AN: 2676528
1040 of 1521
TI: Influence of dissolved organic carbon, pH, and microbial respiration rates on mercury methylation and demethylation in lake water.
AU: Miskimmin,-B.M.; Rudd,-J.W.M.; Kelly,-C.A.
AF: Dep. Zool., Univ. Alberta, Edmonton, Alta. T6G 2E9, Canada
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1992. vol. 49, no. 1, pp. 17-22
NT: Incl. bibliogr.: 27 ref.
LA: English
ER: F (Freshwater)
AB: Effects of changes in DOC concentrations, pH, and microbial respiration rates on specific rates of mercury methylation and demethylation in lake water were studied using radioisotopic techniques. Increased concentrations of DOC resulted in decreased specific rates of net methylation, possibly as a result of complexation of inorganic mercury with DOC. A reduction in pH from 7.0 to 5.0 had the greatest effect, causing to moderate increases in net methylation rate at both low and high DOC concentrations (500-2600 mu M). Rates of respiration (indicative of general rates of microbial activity), which were insensitive to pH change over the range tested (5.0-7.0), had the smallest effect on net methyl mercury production rates.
AN: 2676253
1041 of 1521
TI: The changing global carbon cycle: Dust to dust.
AU: Moore,-B.,III
AF: Univ. New Hampshire, Durham, NH 03824, USA
SO: MAR.-TECHNOL.-SOC.-J. 1991. vol. 25, no. 3, pp. 19-24
NT: Spec. iss.: Global Environmental Change. Part 1.
LA: English
ER: M (Marine)
AB: This paper reviews briefly the global carbon cycle and presents on introductory discussion of the role of the ocean in this cycle including comparisons with the atmosphere and the land.
AN: 2676225
1042 of 1521
TI: Application of a generalized scavenging model to thorium isotope and particle data at equatorial and high-latitude sites in the Pacific Ocean.
AU: Clegg,-S.M.; Bacon,-M.P.; Whitfield,-M.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich, UK
SO: J.-GEOPHYS.-RES. 1991. vol. 96, no. C11, pp. 20,655-670
LA: English
ER: M (Marine)
AB: A generalized trace metal scavenging model has been applied to particle cycle and super(234)Th data at three equatorial Pacific sites, and to dissolved and particulate super(228)Th, super(230)Th, and super(234)Th profiles at a single high-latitude station. The one-dimensional (and here steady state) model consists of two particle classes, small (suspended) and large (sinking). It is driven by particle primary production and parameterized from particle and tracer concentration and flux data. The model has been used to determine, as functions of depth, rates of particle remineralization; aggregation and disaggregation of the small and large-particle classes, respectively, and adsorption and desorption rate constants of thorium. The results are insensitive to the assumed large particle sinking rate of 150 m/d. The profiles of all three tracers at Station P are described satisfactorily by a single set of model parameters. The adsorption rate constant, normalized for the effect of particle concentration, is enhanced in the upper 100 m of the water column by a factor of 2 or greater at all sites. Values of this and the other major model parameters are consistent with earlier results for a variety of oceanic environments.
AN: 2672543
1043 of 1521
TI: Oxic and anoxic decomposition of tubes from the burrowing sea anemone Ceriantheopsis americanus : Implications for bulk sediment carbon and nitrogen balance.
AU: Kristensen,-E.; Aller,-R.C.; Aller,-J.Y.
AF: Inst. Biol., Odense Univ., DK-5230 Odense M, Denmark
SO: J.-MAR.-RES. 1991. vol. 49, no. 3, pp. 589-617
LA: English
ER: M (Marine)
AB: Many marine infaunal animals form organic tube and burrow linings. The infaunal sea anemone, Ceriantheopsis americanus , forms a leathery, fibrous tube lining 2-3 mm thick, similar to 1 cm in diameter, and typically extending 20-30 cm into deposits. Tube fibers are composed of a silk-like protein copolymer, cerianthin. Tubes incubated under oxic and anoxic conditions over a period of 122 days demonstrate that initial rates of whole tube decay are 10-100 times slower than usually found for fresh planktonic debris and aquatic macrophytes despite a relatively low molar C:N ratio of similar to 5.1. First order decomposition rate constants in oxic water, anoxic water and anoxic sediment are similar to 0.76, similar to 0.41 and similar to 0.22/yr for particulate tube carbon and similar to 0.2, similar to 0.1 and similar to 0.1/yr for particulate nitrogen. Tube decomposition stimulates bacterial activity in sediments from below similar to 10 cm depth. In central Long Island Sound muds, tubes apparently account for a minimum of similar to 0.6-1.8% and 2.8-8.4% of the steady state C and N detrital pools in the upper 10-30 cm of the sediment. C. americanus tube production apparently accounts for similar to 9% of the average particulate carbon and similar to 12% of the nitrogen fluxes to the benthos.
AN: 2671523
1044 of 1521
TI: Nutrient cycling and the biogeochemistry of manganese, iron, and zinc in Jellyfish Lake, Palau.
AU: Landing,-W.M.; Burnett,-W.C.; Berry-Lyons,-W.; Orem,-W.H.
AF: Dep. Oceanogr., B-169, Florida State Univ., Tallahassee, FL 32306-3048, USA
SO: LIMNOL.-OCEANOGR. 1991. vol. 36, no. 3, pp. 515-525
LA: English
ER: M (Marine)
AB: The oxic waters in Jellyfish Lake, a stagnant marine lake in Palau, are depleted in NO sub(3) super(-), PO sub(4) super(3-), dissolved Si, Mn, Fe, and Zn, while the underlying anoxic waters are significantly enriched in these species and NH sub(3). NH sub(3) and PO sub(4) super(3-) regeneration and dissolved sulfide production in the anoxic zone yield a stoichiometry of C sub(138)N sub(13)P for organic matter undergoing recycling in the anoxic waters. A two-box model is used to calculate an eddy diffusion coefficient of 0.0015 cm super(2)/s across the chemocline. The upward diffusive loss of NH sub(3) added to the sedimentation rate of N and multiplied by the stoichiometric C:N ratio yields an organic carbon flux into the anoxic waters of 1,200 mu mol C/cm super(2)/yr, which is similar to 13% of the total primary productivity.
AN: 2671461
1045 of 1521
TI: Geochemistry of reef interstitial waters.
AU: Tribble,-G.W.
AF: Dep. Oceanogr., Univ. Hawaii, Honolulu, HI 96822, USA
CO: 12. Annu. Albert L. Tester Memorial Symp., Hawaii, HI (USA), 2-3 Apr 1987
SO: PAC.-SCI. 1988. vol. 42, no. 1-2, pp. 135-136
NT: Summary only.
LA: English
ER: M (Marine)
AB: Water was sampled from the internal framework of a coral reef in Kaneohe Bay, Oahu. Dissolved oxygen levels were low or undetectable in the interstitial water and concentrations of dissolved methane, sulfide, and inorganic carbon were elevated. The reef interstitial water also differed from surface water in having a lower pH and higher alkalinity. Dissolved organic nitrogen and phosphorus concentrations were similar in interstitial and overlying waters, but interstitial waters were enriched with inorganic nutrients. The differences in chemical composition between reef surface water and reef interstitial water appear to result from microbial oxidation of organic matter through both oxic and anoxic pathways. Hydrological investigations indicate that the reef interstitial waters are advectively driven and that exchange with the overlying seawater occurs on a time period of several hours to a few days. The flux of nutrient-enriched water out of the reef framework may thus represent a significant source of remineralized nutrients to reef primary producers.
AN: 2670849
1046 of 1521
TI: High production and highstand shedding from deeply submerged carbonate banks, northern Nicaragua Rise.
AU: Glaser,-K.S.; Droxler,-A.W.
AF: Dep. Geol. and Geophys., Rice Univ., Houston, TX 77251, USA
SO: J.-SEDIMENT.-PETROL. 1991. vol. 61, no. 1, pp. 128-142
LA: English
ER: M (Marine)
AB: Because the shallow isolated carbonate banks on the northern Nicaragua Rise, the Nicaragua/Honduras and southern Jamaica carbonate shelves, and many other modern carbonate banks worldwide, are covered by an average of 20 to 30 m of water and by a thin blanket of coarse carbonate sediments, other carbonate sedimentologists have considered these banks good examples of "incipiently drowned", or even "drowned" carbonate banks. However, based on recent research on the northern Nicaragua Rise, we can demonstrate that these banks currently are healthy producers of large volumes of periplatform sediments (fine aragonite and magnesian calcite), which are exported almost entirely to the deep surrounding slopes.
AN: 2669202
1047 of 1521
TI: Enhanced particle fluxes in Bay of Bengal induced by injection of fresh water.
AU: Ittekkot,-V.; Nair,-R.R.; Honjo,-S.; Ramaswamy,-V.; Bartsch,-M.; Manganini,-S.; Desai,-B.N.
AF: Inst. Biogeochem. and Mar. Chem., Univ. Hamburg, Bundesst. 55, 2000 Hamburg 13, FRG
SO: NATURE. 1991. vol. 351, no. 6325, pp. 385-387
LA: English
ER: M (Marine)
AB: The melting of ice sheets during deglaciation results in the injection of large amounts of fresh water into the oceans. To investigate how such injections might influence particle fluxes in the ocean, and hence the uptake of atmospheric CO sub(2), we deployed three sediment-trap moorings (two traps in each mooring) in the northern, central and southern parts of the Bay of Bengal, respectively. From north to south, the carbonate flux increases, whereas fluxes of opal, organic carbon and particulate matter decrease. The overall flux pattern seems to be controlled by the seasonally varying input from the rivers and the accompanying shift in marine biogenic production. We conclude that freshwater pulses during deglaciation may therefore have caused similar shifts in marine biogenic production, resulting in short-term episodes of increased oceanic uptake of atmospheric CO sub(2).
AN: 2669114
1048 of 1521
TI: The retention of cadmium and zinc in appendicularian houses.
OT: Retention du cadmium et du zinc dans les logettes abandonnees par les appendiculaires
AU: Fisher,-N.S.; Nolan,-C.V.; Gorsky,-G.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11794-5000, USA
SO: OCEANOL.-ACTA. 1991. vol. 14, no. 4, pp. 427-430
LA: English
ER: M (Marine)
AB: The discarded houses of appendicularians can be important components of marine snow and might therefore be instrumental in mediating the vertical flux of metals from surface waters in oceanic ecosystems. Their significance in this regard depends on the retention of metals in these organic debris. To assess this, an experiment was conducted in which the release of cadmium and zinc from discarded houses of the appendicularian Oikopleura longicauda was studied using gamma-emitting radiotracers. The retention curves of the two metals conformed with a single exponential decay loss model. The retention half-times were of the order of two days, suggesting that sinking appendicularian houses would not transport these metals to deep ocean waters but could contribute to their flux out of surface waters.
AN: 2665944
1049 of 1521
TI: Composition and fate of organic matter in submarine cave sediments; Implications for the biogeochemical cycle of organic carbon.
OT: Composition et devenir de la matiere organique sedimentaire dans une grotte sous-marine; consequences sur le cycle biogeochimique du carbone organique
AU: Fichez,-B.
AF: Cent. Oceanol. Marseille, Stn. Mar. Endoume, 13007 Marseille, France
SO: OCEANOL.-ACTA. 1991. vol. 14, no. 4, pp. 369-377
LA: English
ER: M (Marine)
AB: The biochemical composition of the sediments in a Mediteranean submarine cave (Marseille, France) was studied, and a budget for the biogeochemical cycle of organic carbon was calculated. Chloropigment and lipid levels were markedly lower in sediments from the dark inner section of the cave compared to the twilight outer section. These decreased levels were related to the decrease in the vertical inputs of particulate organic matter. Lower decreases were recorded in the sediment content of other organic constituents (organic carbon, organic nitrogen, carbohydrates, proteins). The anlaysis of carbohydrate and protein extracted from sediments (NaOH 1 N, 24 h, 4 degree C) yielded no significant information, demonstrating the ambiguous significance of such a chemical approach in sediments low in organic matter.
AN: 2664108
1050 of 1521
TI: Rare earth elements in the Mediterranean Sea and mixing in the Mediterranean outflow.
AU: Greaves,-M.J.; Rudnicki,-M.; Elderfield,-H.
AF: Dep. Earth Sci., Univ. Cambridge, Downing St., Cambridge CB2 3EQ, UK
SO: EARTH-PLANET.-SCI.-LETT. 1991. vol. 103, no. 1-4, pp. 169-181
LA: English
ER: M (Marine)
AB: Mediterranean surface waters contain elevated levels of the rare earth elements compared to similar nutrient-depleted open ocean waters. Application of a flux balance model shows that the Mediterranean is a net sink for Ce and a net source for the other REE. The abundance pattern of the excess REE required for mass balance is enriched in heavy REE and has a negative Ce anomaly. This supports a marine, possibly coastal, source for the REE. Although the magnitudes of the fluxes involved are consistent with aeolian input, an aeolian source would require large-scale removal of Ce and the light REE within the Mediterranean Sea. A mixing model to compute trace metal anomalies in the Mediterranean outflow predicts the observed REE concentrations well. This implies that Ce behaves conservatively in outflow waters over the calculated one-month period for Mediterranean water to reach the study site. Application to other trace metals gives good agreement for Al, Cd and Mn.
AN: 2661317
1051 of 1521
TI: Oceanic delta-13-carbon values as indicators of atmospheric oxygen depletion.
AU: Hoffman,-A.; Gruszczynski,-M.; Malkowski,-K.
AF: Inst. Paleobiol., Pol. Acad. Sci., Al. Zwirki Wigury 93, PL-02-089 Warszaw, Poland
SO: MOD.-GEOL. 1990. vol. 14, no. 3, pp. 211-221
LA: English
ER: M (Marine)
AB: Theoretical analysis of the environmental meaning and consequences of very large drops in the carbon isotopic composition of seawater demonstrates they indicate that the exosystem has developed a potential for becoming a substantial sink for oxygen. When a drop in the oceanic carbon-13-delta value is of a magnitude comparable to those recorded close to the Precambrian-Cambrian and Permian-Triassic transitions, it indicates a global-scale preponderance of organic carbon oxidation over its deposition in the ocean. Two alternative scenarios of such a process can be envisaged. The onset of deep-water circulation may bring oxygen down to the bottom of the previously stagnant and stratified ocean ("overfed-to-hungry-ocean switch" scenario). Atmospheric oxygen then sinks in the ocean, where it oxidizes the reduced chemical species that accumulated earlier at the seabottom. Alternatively, oxidation of organic carbon may occur via bacterial sulfate-to-sulfide reduction in the anoxic, lower box of stagnant and stratified ocean ("sulfate-reduction" scenario).
AN: 2658679
1052 of 1521
TI: The seasonal behaviour of carbon dioxide and oxygen in the coastal North Sea along the Netherlands.
AU: Hoppema,-J.M.J.
AF: Netherlands Inst. Sea Res., P.O. Box 59, 1790 AB Den Burg, Texel, Netherlands
SO: NETH.-J.-SEA-RES. 1991. vol. 28, no. 3, pp. 167-179
LA: English
ER: M (Marine)
AB: Total CO sub(2) (TCO sub(2)) distribution patterns in the coastal North Sea in different seasons showed decreasing values towards the open sea. The higher values near the coast were caused by TCO sub(2) outflow from the Rhine/Meuse. The highest values were observed in Nov, irrespective of the salinity. Mixing generally resulted in linear relationships between TCO sub(2) and salinity, but scattering was lowest in Nov. Both pH (measured) and pCO sub(2) (calculated) clearly demonstrated the influence of biological activity on the CO sub(2) system. In Nov, pCO sub(2) was very high near the coast (> 450 mu atm). This is attributed mainly to mixing, and only partly to mineralization. The oxygen distributions were consistent with those of the CO sub(2)-related parameters, the deviations being opposite. The data showed that, in accordance with theory, the equilibration of O sub(2) with the atmosphere was faster than for CO sub(2). TCO sub(2)- alkalinity diagrams were only of limited value, since normalization to constant salinity was hampered by freshwater variations of TCO sub(2) combined with the variability of the residence time of the water masses in the coastal area.
AN: 2658655
1053 of 1521
TI: New life discovered in Lake Baikal. A community based on bacterial chemosynthesis.
OT: Novoe v prirode-Bajkala, soobshchestvo, osnovannoe na bakterial'nom khemosinteze
AU: Kuznetsov,-A.P.; Strizhov,-V.P.; Kuzin,-V.S.; Fialkov,-V.A.; Yastrebov,-V.S.
AF: IOAN, Moscow, Russia
SO: IZV.-AN-S.S.S.R.-BIOL.. 1991. no. 5, pp. 766-772
LA: Russian
ER: F (Freshwater)
AB: The authors describe a bottom community hitherto unknown to science and first discovered in the summer of 1990. The community is an extraordinarily dense settlement of sponges, amphipods, planarians, fishes, other animals and vast mat-like bacterial bottom covers. In its structure and function the community is analogous to oceanic bottom communities found at cold or slightly heated sulfide-methane seeps and hydrated gas vents in plate subduction regions. There is evidence that the metabolism of the community is based on methane (CH sub(4)) of biogenic genesis intensively implicated in biochemosynthesis produced in the community by methanotrophic bacteria.
AN: 2657828
1054 of 1521
TI: Composition and bacterial utilization of photosynthetically produced organic matter in an eutrophic lake.
AU: Siuda,-W.; Wcislo,-R.; Chrost,-R.J.
AF: Dep. Environ. Microbiol., Inst. Microbiol., Univ. Warsaw, ul. Karowa 18, 00-325 Warsaw, Poland
SO: ARCH.-HYDROBIOL. 1991. vol. 121, no. 4, pp. 473-484
NT: Bibliogr.: 27 ref.
LA: English
ER: F (Freshwater)
AB: Photosynthetic production, composition and utilization of organic matter were studied in the pelagic zone of highly eutrophic Lake Mikolajskie (Mazurian Lake District, Poland). About 97% of total fixed super(14)C-CO sub(2) was photosynthetically incorporated into algal cells, and about 3% of super(14)C was fixed by microplankton in the darkness. Twelve percent of photosynthetically produced organic carbon (PhOC) was released by phytoplankton into the water, 8% of PhOC was respired, and about 80% of super(14)C-PhOC remained in algal cells. Chemical composition of PhOC strongly depended upon light conditions. super(14)C was predominantly incorporated into the two-molecular-weight compounds (LMWC) and polysaccharides. Proteins and lipids were produced in smaller quantities, however, their production significantly increased at low light intensity.
AN: 2655424
1055 of 1521
TI: Decomposition of Rhizophora mangle, Avicennia schaueriana and Laguncularia racemosa leaves in a mangrove of Paranagua Bay (southeastern Brazil).
AU: Sessegolo,-G.C.; Lana,-P.C.
AF: Cent. Biol. Mar., Univ. Fed. Parana, 83200 Pontal do Sul, Parana, Brazil
SO: BOT.-MAR. 1991. vol. 34, no. 4, pp. 285-289
LA: English
ER: M (Marine)
AB: The decomposition of senescent leaves of the mangrove species Rhizophora mangle L., Avicennia schaueriana Stapf et Leechman and Laguncularia racemosa Gaertn. was investigated at Baguacu tidal creek (Paranagua Bay, SE Brazil), under subtidal, intertidal and supratidal conditions. Overall decomposition rates were evaluated by weight loss over time in litter bags. Half-life for decomposition varied between 10.5 days for Avicennia leaves permanently immersed in the water column and 249 days for Rhizophora leaves under supratidal conditions. Instantaneous decomposition constants (k), that ranged from -0.003 (Rhizophora , supratidal) to -0.043 (Avecennia , immersed), were consistently higher with decreasing elevation of site location, indicating that submersion frequency is important in determining the rate of plant breakdown.
AN: 2654529
1056 of 1521
TI: Major role of the cyanobacterium Trichodesmium in nutrient cycling in the North Atlantic Ocean.
AU: Carpenter,-E.J.; Romans,-K.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11794-5000, USA
SO: SCIENCE-WASH.. 1991. vol. 254, no. 5036, pp. 1356-1358
LA: English
ER: M (Marine)
AB: The diazotrophic cyanobacterium Trichodesmium is a large similar to 0.5 by 3 millimeters) phytoplankter that is common in tropical open-ocean waters. Measurements of abundance, plus a review of earlier observations, indicate that it, rather than the picophytoplankton, is the most important primary producer (about 165 milligrams of carbon per square meter per day) in the tropical North Atlantic Ocean. Inclusion of this organism, plus the abundant diazotrophic endosymbiont Richelia intracellularis that is present in some large diatoms, in biogeochemical studies of carbon and nitrogen may help explain the disparity between various methods of measuring productivity in the oligotrophic ocean. Carbon and nitrogen fixation by these large phytoplankters also introduces a new paradigm in the biogeochemistry of these elements in the sea.
AN: 2653224
1057 of 1521
TI: Scientifically based strategies for marine environmental protection and management.
AU: Gray,-J.S.; Calamari,-D.; Duce,-R.; Portmann,-J.E.; Wells,-P.G.; Windom,-H.L.
AF: Dep. Mar. Zool., Univ. Oslo, P.O. Box 1064, 0316 Blindern, Oslo 3, Norway
SO: MAR.-POLLUT.-BULL. 1991. vol. 22, no. 9, pp. 432-440
LA: English
ER: M (Marine)
AB: During the last decades, mankind has faced a wide range of environmental degradations: changes in climatic conditions and biogeochemical cycles, a number of ecoaccidents, the appearance of xenobiotics in remote areas and a general world-wide deterioration in environmental quality. The results in the aquatic environment were dramatic with effects such as massive fish kills and large areas of sea bed devoid of oxygen. Measures taken to protect the aquatic environment from such effects thus far have been based on strategies such as the Water Quality Standards, Black and Grey Lists and the Precautionary Principle.
AN: 2652863
1058 of 1521
TI: Ocean's role in the global carbon cycle. Foreign trip report, June 1, 1990-December 20, 1990.
AU: Joos,-L.F.
CA: Oak Ridge Natl. Lab., TN (USA)
SO: 1990. 17 pp
NT: NTIS Order No.: DE91005985/GAR.
RN: ORNL/FTR-3847 (ORNLFTR3847)
LA: English
ER: M (Marine)
AB: The traveler collaborated with Dr. J.L. Sarmiento of the Program in Atmospheric Sciences, Princeton University, and Dr. U. Siegenthaler of the University of Bern in box-model studies of the potential enhancement of oceanic CO sub(2) uptake by fertilizing the southern ocean with iron. As a result of this collaboration, a letter describing the results was submitted to the journal Nature. Sensitivity studies were carried out to gain a better understanding of the processes involved for a hypothetical iron fertilization of the ocean. (Contract AC05-84OR21400. Sponsored by Department of Energy, Washington, DC.)
AN: 2652543
1059 of 1521
TI: Aerobic and anaerobic mineralization of organic material in marine sediment microcosms.
AU: Hansen,-L.S.; Blackburn,-T.H.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 75, no. 2-3, pp. 283-291
NT: Bibliogr.: 40 ref.
LA: English
ER: M (Marine)
AB: Fluxes of total CO sub(2), O sub(2), NO sub(3) super(-)+NO sub(2) super(-), DON (dissolved organic nitrogen) and HS super(-) were measured across the interface of a coastal bay sediment for 43 d. The seawater overlying the defaunated sediment cores was changed continuously. Two treatments were employed: oxygenated overlying water (OX-cores) and anoxic water (AN-cores). Fluxes were measured before and after addition of an organic substrate, and loss of POM (particulate organic matter) was measured at the end of the experiment. Loss of POC (particulate organic carbon) from the sediment was the same under aerobic and anaerobic conditions. However, the highest efflux of CO sub(2) was measured in the OX-cores, and the highest efflux of DOC occurred in the AN-cores before and after addition of fresh substrate. Similarly, loss of PON (particulate organic nitrogen) from the sediment was the same in the 2 treatments, but the highest fluxes of NH sub(4) super(+) and DON were measured in the AN-cores.
AN: 2651403
1060 of 1521
TI: Sediment phosphorus loading beneath dense canopies of aquatic macrophytes.
AU: Frodge,-J.D.; Thomas,-G.L.; Pauley,-G.B.
AF: Washington Coop. Fish. and Wildl. Res. Unit, WH-10, Univ. Washington, Seattle, WA 98195, USA
SO: LAKE-RESERVOIR-MANAGE. 1991. vol. 7, no. 1, pp. 61-71
LA: English
ER: F (Freshwater)
AB: Dense surface canopies of aquatic macrophytes were associated with significant changes in the physical and chemical water quality of two shallow Pacific Northwest lakes. Internal loading of phosphorus (P) was observed at the sediment-water interface beneath canopies of Ceratophyllum demersum L. and Myriophyllum exalbescens (Fern.) Jeps. and in deep open-water areas when dissolved oxygen (DO) concentrations were less than or equal to 0.4 mg/L. Aerobic release of P was observed at sites with surface covers of the green filamentous algae Pithophora sp. where concentrations of DO were > 20 mg/L and pH > 9. An increase in surface P concentrations was also observed in sites dominated by the floating leafed Brasenia schreberi Gmel., and appeared to be associated with leaf decay within the surface canopy. There was an apparent net loss of phosphorus to the sediments beneath both submergent and floating leafed canopies when DO concentrations were greater than or equal to 0.4 mg/L. The removal or reduction of the plant canopies could simultaneously reduce anoxic P release, while increasing aerobic P release. These P cycling mechanisms should be considered in the management of aquatic macrophytes.
AN: 2650918
1061 of 1521
TI: The processing of elements by mires in agricultural landscape: Mass balances based on sub-surface hydrology.
AU: Kruk,-M.
AF: Dep. Plant Ecol., Inst. Ecol., Pol. Acad. Sci., Dziekanow Lesny (near Warsaw), 05-092 Lomianki, Poland
SO: EKOL.-POL. 1990. vol. 38, no. 1, pp. 73-117
NT: Published 1991.
LA: English
ER: F (Freshwater)
AB: Small mires located in hollows with no surface outflows were subject to biogeochemical studies by input-output balance method based on measurements of groundwater flows. Estimates were made of water balance as well as balance of dissolved forms of: N (including N-NO sub(3), N-NH sub(4), N sub(org)), K, Na, Ca, Mg, S-SO sub(4) and Cl. The following undrained mires were examined: two with minerotrophic fen and one with ombrotrophic-transition bog. Also a drained minerotrophic mire was studied. It was observed that nitrogen outflow from undrained mires was considerably smaller. The mire with ombrotrophic-transition bog could retain a substantial part of a scanty inflow of the examined elements, while mires with minerotrophic fen - upmost a tiny part of a rich inflow mainly from catchment basin. Drained minerotrophic mire was no longer apt to retain a majority of elements, nitrogen in particular.
AN: 2650777
1062 of 1521
TI: A sea of change: Monitoring the oceans' carbon cycle.
AU: Karl,-D.M.; Winn,-C.D.
SO: ENVIRON.-SCI.-TECHNOL. 1991. vol. 25, no. 12, pp. 1976-1981
LA: English
ER: M (Marine)
AN: 2650736
1063 of 1521
TI: Dissimilatory Fe(III) and Mn(IV) reduction.
AU: Lovley,-D.R.
AF: Water Resour. Div., U.S. Geol. Surv., 430 Natl. Cent., Reston, VA 22092, USA
SO: MICROBIOL.-REV. 1991. vol. 55, no. 2, pp. 259-287
LA: English
ER: F (Freshwater)
AB: The oxidation of organic matter coupled to the reduction of Fe(III) or Mn(IV) is one of the most important biogeochemical reactions in aquatic sediments, soils, and groundwater. This process plays an important role in the oxidation of natural and contaminant organic compounds in a variety of environments and contributes to other phenomena of widespread significance such as the release of metals and nutrients into water supplies, the magnetization of sediments, and the corrosion of metal. Until recently, much of the Fe(III) and Mn(IV) reduction in sedimentary environments was considered to be the result of nonenzymatic processes. However, microorganisms which can effectively couple the oxidation of organic compounds to the reduction of Fe(III) or Mn(IV) have recently been discovered. With Fe(III) or Mn(IV) as the sole electron acceptor, these organisms can completely oxidize fatty acids, hydrogen, or a variety of monoaromatic compounds. The available evidence indicates that this enzymatic reduction of Fe(III) or Mn(IV) accounts for most of the oxidation of organic matter coupled to reduction of Fe(III) and Mn(IV) in sedimentary environments. Little is known about the diversity and ecology of the microorganisms responsible for Fe(III) and Mn(IV) reduction, and only preliminary studies have been conducted on the physiology and biochemistry of this process.
AN: 2650048
1064 of 1521
TI: Microbial activity in the sediments of a eutrophic lagoon.
OT: Il ruolo dell'attivita microbica dei sedimenti nelle distrofie degli ambienti acquatici
AU: Izzo,-G.
AF: ENEA-Casaccia, C.P. 2400, 00100 Rome, Italy
CA: Gruppo Biologia Marina S.S.S.P., Torino (Italy)
CO: 19. Congr. della Societa Italiana di Biologia Marina, Naples (Italy), 24-28 Sep 1987
SO: OEBALIA. pp. 441-451
NT: 15-1, N.S.
LA: Italian
ER: B (Brackish)
AB: Th sulfate-reducing activity of a eutrophic lagoon (Orbetello, Tuscany, Italy) was measured in the sediments at two-week intervals for a period of 7 months. The summer increase of this activity seems to be responsible for anoxic crises of the water column induced by the chemical oxidation of the produced sulphides. The daily cycle of the dissolved oxygen in the water column shows a strong night consumption. The redox profiles in sediments which are considered indicators of microbial activity seem to be influenced by internal water circulation. A water flow was induced artificially to prevent anoxic phenomena.
AN: 2649171
1065 of 1521
TI: A link between biologically imported particulate organic nutrients and the detritus food web in reef communities.
AU: Rothans,-T.C.; Miller,-A.C.
AF: Dep. Biol., California State Univ., Long Beach, CA 90840-3702, USA
SO: MAR.-BIOL. 1991. vol. 110, no. 1, pp. 145-150
NT: Bibliogr.: 30 ref.
LA: English
ER: M (Marine)
AB: Previous work with planktivorous fishes has shown that they import particulate organic and inorganic material to reefs in the form of fecal pellets, which, in part, are deposited in crevices on the reef where these fishes shelter during their inactive period. We examined the attractiveness of fish feces to potential reef detritivores by placing traps baited with planktivorous fish feces, along with unbaited control traps, in crevices on rocky reefs at Santa Catalina Island, California, USA, between June 1982 and November 1983, and on coral reefs at St. Croix, U.S. Virgin Islands, during June 1983. Significantly more animals (the majority being crustaceans) were trapped in the baited traps compared to the unbaited controls on both reefs. There was also a significant association between the presence of trapped animals and fish feces at Santa Catalina Island (p = 0.009).
AN: 2646163
1066 of 1521
TI: Oceanic phytoplankton communities: Our changing perception.
AU: Glover,-H.E.
AF: Box 165, Lakeside Dr., Boothbay, ME 04537, USA
SO: REV.-AQUAT.-SCI. 1991. vol. 5, no. 3-4, pp. 307-331
LA: English
ER: M (Marine)
AB: Ocean systems were traditionally thought to be static aqueous deserts of low productivity with a low "steady-state" diffusional supply of nitrate across the thermocline. Over the last decade, this view has been increasingly challenged due to several factors: the adoption of new methodologies, increased sampling frequency, and the discovery of a diverse picophytoplankton (< 2 mu m) that provides most of the primary production. Our current view of oceanic nutrient supply recognizes the importance of episodic events that increase the nitrate flux to surface waters and rapidly enhance photosynthetic rates. Recent estimates of oceanic primary production and that portion supported by nitrate have been revised upwards, which has a direct impact upon calculations of global carbon fluxes. We now believe that there is a rapid cycling of carbon and nitrogen in the open sea that is driven by synergistic picoplankton interactions between photoautotrophs, chemoautotrophs, methanotrophs, heterotrophic bacteria, and their protozooplankton grazers in the water column and on microaggregates.
AN: 2640934
1067 of 1521
TI: Production and consumption of dimethyl-sulfoniopropionate in marine microbial mats.
AU: Visscher,-P.T.; Gemerden,-H.-van
AF: Div. Mar. and Atmos. Chem., Rosenstiel Sch. Mar. and Atmos. Sci., 4600 Rickenbacker Causeway, Miami, FL 33149-1098, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1991. vol. 57, no. 11, pp. 3237-3242
LA: English
AB: The fate of dimethyl-sulfoniopropionate (DMSP), a major sulfonium compound in marine ecosystems, was examined in Microcoleus chthonoplastes -dominated microbial mats. Chemical decomposition of DMSP was observed under laboratory conditions at pH values higher than 10.0. pH profiles measured in situ showed that these highly alkaline conditions occurred in microbial mats. Axenic cultures of M. chthonoplastes contained 37.3 mu mol of DMSP g of protein super(-1), which was partially liberated when the cells were subjected to an osmotic shock. DMSP-amended mat slurries showed a rapid turnover of this compound. The addition of glutaraldehyde blocked DMSP decrease, indicating biological consumption. Populations of potential dimethyl sulfide consumers were found in the top 10 mm of the mat.
AN: 2640925
1068 of 1521
TI: A model system derived from marine diatoms for investigating the activity of particle-associated bacteria.
AU: Griffith,-P.C.; Fletcher,-M.
AF: Cent. Mar. Biotech., Univ. Maryland, 600 E. Lombard St., Baltimore, MD 21202, USA
SO: J.-MICROBIOL.-METHODS. 1990. vol. 12, no. 2, pp. 65-74
LA: English
ER: M (Marine)
AB: A model system for examining bacterial attachment to and degradation of marine particulate matter is described. The model particles consisted of a hydrophilic matrix derived from marine diatoms, contained primarily Si, Ca and Al oxides, and had high surface area relative to weight. A marine Pseudomonas sp. (NCMB 2021) attached readily to the particles. Biomass of free and particle-associated bacteria was quantified using direct counts, radiolabeling, and protein determination. Bacterial activity was assayed by measuring the hydrolysis of L-leucine-methylcumarinylamide, a fluorescently labeled substratum, that served as an analog to protein macromolecules. The cell-specific rate of substratum hydrolysis by attached bacteria was half that of free-living bacteria.
AN: 2636287
1069 of 1521
TI: Effect of growth and subsequent decomposition of blue-green algae on the transformation of iron and manganese in submerged soils.
AU: Das,-S.C.; Mandal,-B.; Mandal,-L.N.
AF: Micronutr. Res. Lab., Dep. Agric. Chem. and Soil Sci., Bidhan Chandra Krishi Viswavidyalaya, Kalyani 741235, West Bengal, India
SO: PLANT-SOIL. 1991. vol. 138, no. 1, pp. 75-84
LA: English
ER: F (Freshwater)
AB: N sub(2)-fixing blue-green algae (Cyanobacteria), besides enriching soils with N and organic carbon, may modify chemical and electro-chemical properties of the soils resulting in a change in availability of some micronutrient elements. An experiment was conducted to study the effects of growth and subsequent decomposition of blue-green algae on changes in the different forms of Fe and Mn in four soils under submerged condition. A mixed algal culture containing Anabaena, Nostoc, Cylindrospermum), and Tolypothrix was used as inoculum. It was allowed to grow for 2 months, after which the soils were extracted. Growth of blue-green algae in submerged rice soils caused a decrease in the NH sub(4) OAc-extractable forms of Fe and MN with concomitant increases in all the other four determined forms of the elements. Such decreases and/or increases in different forms of Fe and Mn in soils were explained as being due to release of O sub(2), addition of organic matter and liberation of extracellular organic compounds by the blue-green algae during their growth.
AN: 2636174
1070 of 1521
TI: On the interrelationship between temporal trends in delta super(13)C, delta super(18)O, and delta super(34)S in the World Ocean.
AU: Hoffman,-A.; Gruszczynski,-M.; Malkowski,-K.
AF: Inst. Paleobiol., Pol. Acad. Sci., Al. Zwirki i Wigury 93, PL-02-089 Warszawa, Poland
SO: J.-GEOL. 1991. vol. 99, no. 3, pp. 355-370
LA: English
ER: M (Marine)
AB: The phenomena of (i) inverse correlation between the oceanic carbon and sulfur isotopic curves, and (ii) covariation between the oceanic carbon and oxygen isotopic curves at all their major excursions appear as paradoxes in the current paradigm of global biogeochemical cycles. These phenomena, however, are fully explicable by our model proposing that the ocean alternates between two general modes: stagnant, stratified, and net autotrophic (overfed) ocean, and vigorously mixed and net heterotrophic (hungry) ocean. The model has far-reaching implications for (i) the causal explanation of both secular trends and major shifts in the oceanic isotopic curves, and (ii) for the application of oxygen isotopic data for paleotemperature and paleoenvironment determinations.
AN: 2633775
1071 of 1521
TI: The transport of CO sub(2) into Arctic and Antarctic Seas: Similarities and differences in the driving processes.
AU: Anderson,-L.G.; Jones,-E.P.
AF: Dep. Anal. and Mar. Chem., Univ. Goteborg, S-412 96 Goteborg, Sweden
SO: J.-MAR.-SYST. 1991. vol. 2, no. 1-2, pp. 81-95
LA: English
ER: M (Marine)
AB: In polar regions, the partial pressure of CO sub(2) in the ocean is decreased mainly by two processes, a decrease in temperature and biological productivity. In the Arctic, the vertical transport of cooled surface water by deep convection mainly takes place in the Greenland Sea and penetrates to a very large depth, while in the Antarctic the deep convection does not reach the same depths, at least not as frequently. Biological production is significant for the vertical transport of carbon in both the Arctic and Antarctic; however, in the Arctic the production is mainly over the large shelves, while in the Antarctic it takes place mostly over the deep ocean. Total alkalinity, total carbonate, calcium, oxygen, salinity and temperature data from several expeditions in the Arctic and the SWEDARP 88/89 expedition in the Antarctic are used in this discussion.
AN: 2633567
1072 of 1521
TI: Geochemistry and paleoceanographic setting of central Nevada bedded barites.
AU: Jewell,-P.W.; Stallard,-R.F.
AF: Dep. Geol. and Geophys. Sci., Princeton Univ., Princeton, NJ 08544, USA
SO: J.-GEOL. 1991. vol. 99, no. 2, pp. 151-170
LA: English
ER: M (Marine)
AB: The bedded barite deposits of central Nevada are hosted by rocks of the Roberts Mountains allochthon and constitute the largest barite reserves in North America. Detailed geochemical studies of three barite deposits in the Devonian Slaven Chert indicate that rocks surrounding the barite have elevated concentrations of carbon and phosphorus relative to nonbarite-bearing rocks. Rare earth element data suggest that the barites were deposited in oxygenated seawater far from a spreading center. The assembled data suggest a biogenic rather than a hydrothermal origin for the barite deposits. A model is proposed in which the barites were deposited at the O sub(2)-H sub(2)S transition of a coastal upwelling system in the Late Devonian ocean.
AN: 2633234
1073 of 1521
TI: Some aspects of the nitrogen cycle in a Californian strand ecosystem.
AU: Holton,-B.,Jr.; Barbour,-M.G.; Martens,-S.N.
AF: Dep. Bot., Univ. California, Davis, CA 95616-8537, USA
SO: MADRONO. 1991. vol. 38, no. 3, pp. 170-184
LA: English
ER: M (Marine)
AB: Nitrogen inputs and storage pools were quantified for 20 months on a perennial grass dominated beach-foredune area at Pt. Reyes National Seashore, CA. Atmospheric input of ammonium and nitrate by bulk precipitation (rain + dry fallout) was 1.6 kg N/ha/yr and by summer fog condensation was 4.2 kg N/ha/yr. Non-symbiotic nitrogen fixation was not detected and fixation by a nodulated legume species is negligible relative to atmospheric inputs. The total ecosystem nitrogen pool was only 390 kg/ha, 78% of which was soil organic nitrogen, 18% was in vegetation, and 4% was inorganic soil nitrogen. Living vascular plant tissue contained 1.7% nitrogen - a value typical of crop plants on fertile soil - despite soil nitrogen content < 0.006%.
AN: 2631604
1074 of 1521
TI: Phosphorus solubilizing yeasts in estuarine environment.
AU: Naik,-M.V.; D'-souza,-J.; Araujo,-A.
AF: Cent. Postgrad. Instruct. and Res., Univ. Bombay, Panaji, Goa 403 001, India
SO: INDIAN-J.-MAR.-SCI. 1982. vol. 11, no. 2, pp. 197-198
LA: English
ER: B (Brackish)
AB: Estuarine yeasts (42) were qualitatively screened for phosphorus solubilizing ability and 23 isolated were later quantitatively tested in Czapek-Dox medium containing tricalcium phosphate as phosphorus source. P-solubilizing activity was maximum in pH range 6-6.5 and an incubation period of 6 days was required for an appreciable quantity of phosphorus to be leached into the medium. The maximum amount of phosphorus was solubilized by Torulopsis glabrata (61.3%) followed by Kloeckera apiculata (46%) and Hansenula anomala (43%).
AN: 2631504
1075 of 1521
TI: Laboratory investigations into the effect of marine organic material on the sea-salt aerosol generated by bubble bursting.
AU: Cloke,-J.; McKay,-W.A.; Liss,-P.S.
AF: Sch. Environ. Sci., Univ. East Anglia, Norwich NR4 7TJ, UK
SO: MAR.-CHEM. 1991. vol. 34, no. 1-2, pp. 77-95
LA: English
ER: M (Marine)
AB: A simple aerosol generation rig has been used to investigate the effect of marine organic material on the flux and inorganic particulate enrichment of marine aerosol. Aerosol was generated in the laboratory from UK coastal seawater samples collected on the monthly basis for 1 year. Initial aerosol generation rates showed no significant seasonal trend, whereas the total amount of aerosol generated before the rate fell to the baseline reached a plateau at around 60 ml from March to October, a factor of six greater than earlier in the year. Dissolved organic carbon (DOC) and surfactant activity have been measured in seawater. The measurements show evidence of seasonal cycles for both determinants. Surfactant activity shows a broad peak in the late autumn. Peak DOC concentrations were seen in early summer. The surfactant-to-DOC ratio varies seasonally. Particulate organic carbon (POC) is highly variable, the ratio of POC to particulate loading being more useful. Peak values may indicate biological production.
AN: 2630706
1076 of 1521
TI: Leaf litter decomposition in three Louisiana freshwater forested wetland areas with different flooding regimes.
AU: Conner,-W.H.; Day,-J.W.,Jr.
AF: Baruch Forest Sci. Inst., Box 596, Georgetown, SC 29442, USA
SO: WETLANDS. 1991. vol. 11, no. 2, pp. 303-312
LA: English
ER: F (Freshwater)
AB: Litter decomposition was studied for one year in three Louisiana forested wetland sites with different flooding regimes. Decomposition was significantly higher in a crayfish pond where flooding was manipulated by pumping. Only 20% of the original dry mass remained after 46 weeks versus over 40% in the natural and impounded wetland forests. Nitrogen was immobilized in the natural and impounded areas but was mineralized during the spring and summer in the managed area. Phosphorus was not immobilized in the natural and impounded areas like nitrogen but was mineralized much more slowly in these areas than it was in the managed area. Because of the slower decomposition in the natural and impounded areas, falling leaf litter buries the old, partially decomposed material. Thus, there tends to be a net accumulation of organic matter, nitrogen, and phosphorus in stagnant, more flooded areas and mineralization and/or export from free-flowing areas.
AN: 2630652
1077 of 1521
TI: (Phosphorus in aquatic sediments: Geochemical forms and identification methods).
OT: Le phosphore dans les sediments aquatiques: Formes geochimiques et methodes d'identification
AU: Andrieux,-F.
AF: IFREMER, Cent. Brest, Dep. Environ. Littoral, B.P. 70, 29280 Plouzane, France
SO: PLOUZANE,-FRANCE-IFREMER,-CENTRE-DE-BREST 1991. no. 91.12, 71 pp
NT: IFREMER Brest DRO-EL/91.12.
LA: French
ER: M (Marine)
AB: The geochemical forms of phosphorus in particulate matter and sediments are described along with the global and specific methods used for their determination. Then, the concentrations found by several authors in different sediments are reviewed. Finally, works on the bioavailability of phosphorus from sediments are described and they indicate the difficulty of its evaluation for the different forms encountered.
AN: 2629723
1078 of 1521
TI: Our changing planet: The FY 1992 U.S. Global Change Research Program. A report by the Committee on Earth and Environmental Sciences. A supplement to the U.S. President's fiscal year 1992 budget.
CA: Federal Coord. Counc. for Science, Engineering and Technology, Washington, DC (USA)
SO: 1991. 102 pp
NT: NTIS Order No.: PB91-145805/GAR.
LA: English
AB: The USGCRP was developed in response to the evolving nature of Earth science research to a more multidisciplinary or Earth System Science approach. The foundation of Earth System Science is the belief that sound scientific information on global change must be derived from a comprehensive, integrated view of the interactions among key components of the Earth system, and the influence of human activities on them. The four FY 1992 Integrating Themes are: Climate Modeling and Prediction: Global Water and Energy Cycles; Global Carbon Cycle; and Ecological Systems and Population Dynamics.
AN: 2627088
1079 of 1521
TI: Modeling pCO sub(2) in the upper ocean. A review of relevant physical, chemical, and biological processes.
AU: Archer,-D.
CA: Washington Univ., Seattle (USA). Dep. of Oceanography
SO: REP.-U.S.-DEP.-ENERGY. 1990. 69 pp
NT: NTIS Order No.: DE91004696/GAR.
RN: DOE/RL/01830-H5T (DOERL01830H5T)
LA: English
ER: M (Marine)
AB: This report summarizes our current understanding of the physical, chemical, and biological processes that control the natural cycling of carbon dioxide (CO(sub 2)) in the surface ocean. Three families of mixed layer models have been developed. This paper explores behavioral distinctions between the three types of models, and summarizes previously published comparisons of the generality, accuracy, and computational requirements of the three models. The application of mixed layer models to treatment of sea ice is also reviewed. (Contract AC06-76RL01830. Sponsored by Department of Energy, Washington, DC.)
AN: 2625081
1080 of 1521
TI: Direct measurement of dissolved inorganic nitrogen exchange and denitrification in individual polychaete (Nereis virens ) burrows.
AU: Kristensen,-E.; Jensen,-M.H.; Aller,-R.C.
AF: Inst. Biol., Odense Univ., DK-5230 Odense M, Denmark
SO: J.-MAR.-RES. 1991. vol. 49, no. 2, pp. 355-377
LA: English
ER: M (Marine)
AB: The burrows of macroinfauna are significant sites of sediment-water nitrogen exchange and associated microbial activity. In this study, the exchange of dissolved inorganic nitrogen (DIN) and nitrogen cycle reaction rates were quantified in individual burrows of the estuarine polychaete Nereis virens . Burrow ventilation rate and DIN (NH sub(4) super(+), NO sub(2) super(-), NO sub(3) super(-) and N sub(2)O) exchange were determined. Indirect estimates of nitrification corresponded to the burrow release of NO sub(2) super(-) without C sub(2)H sub(2). Approximately half of the NO sub(2) super(-) + NO sub(3) super(-) uptake in burrows was due to denitrification. In microcosms with and without N. virens), denitrification was stimulated 3-fold by N. virens and the ratio denitrification/nitrification increased. The changes in DIN flux and denitrification caused by N. virens corresponded well to the rates extrapolated from individual burrows to the appropriate worm density. At the abundance used, N. virens burrows were responsible for 37% and 66% of the total sediment nitrification and denitrification, respectively.
AN: 2623582
1081 of 1521
TI: Fungi and their biomass in detritus of the seagrass Thalassia hemprichii (Ehrenberg) Ascherson.
AU: Sathe,-V.; Raghukumar,-S.
AF: Biol. Oceanogr. Div., Natl. Inst. Oceanogr., Dona Paula, Goa 403 004, India
SO: BOT.-MAR. 1991. vol. 34, no. 4, pp. 271-277
LA: English
ER: M (Marine)
AB: Four different stages of detritus from the seagrass Thalassia hemprichii from two coral islands in the Lakshadweep Archipelago, Arabian Sea were examined for the presence of fungi. Direct microscopic examination revealed different kinds of hyphae and unicellular thraustochytrid fungi, particularly in later stages of decomposition. Highest values of biomass estimated by direct observations were 31840 x 10 super(-6) g mycelial fungi per g dry wt. detritus in detrital fragments from the sediment and 2320 x 10 super(-6) g per g dry wt. of detritus for thraustochytrids in dark brown decaying leaves, corresponding to 3.2 and 0.23% per g dry wt. detritus respectively. The significance of these values which are higher than those reported for other submerged marine macrophyte detritus is discussed. Isolation of fungi in culture yielded thraustochytrids and terrestrial species of mycelial fungi from detritus.
AN: 2623405
1082 of 1521
TI: Time-dependent coupling of inorganic and organic nitrogen uptake and regeneration in the plume of the Chesapeake Bay estuary and its regulation by large heterotrophs.
AU: Glibert,-P.M.; Garside,-C.; Fuhrman,-J.A.; Roman,-M.R.
AF: Horn Point Environ. Lab., Univ. Maryland, P.O. Box 775, Cambridge, MD 21613, USA
SO: LIMNOL.-OCEANOGR. 1991. vol. 36, no. 3, pp. 895-909
LA: English
ER: B (Brackish)
AB: Nitrogen uptake and regeneration in the plume of the Chesapeake Bay estuary was studied during a series of four cruises (1985-1986). During each season we followed the short-term patterns in inorganic (NH sub(4) super(+), NO sub(3)-, NO sub(2) super(-)), and organic (urea and dissolved free amino acids--DFAA) nitrogen uptake and regeneration as plume water aged and became incorporated into ambient coastal water over 1-3 d. There was little influence of seasonally changing temperature on inorganic nitrogen uptake rates: the highest specific and absolute hourly rates of uptake occurred in April, when the availability of total N was at a seasonal high; rates were somewhat lower in early and late summer and were lowest in February. NH sub(4) super(+) regeneration rates, on the other hand, were highly correlated with temperature, with the highest rates occurring in late summer. Rates of DFAA uptake were highest in June. Urea contributed up to 70-80% of the total N utilized during winter and summer; in spring most nitrogen uptake was in the forms of NO sub(3) super(-) and NH sub(4) super(+). In winter most organic N release was not grazer mediated, but instead was more likely due to nutrient-deficient phytoplankton. In late summer, there seemed to be more dissolved organic N release by grazers.
AN: 2622244
1083 of 1521
TI: High turnover rates of dissolved organic carbon during a spring phytoplankton bloom.
AU: Kirchman,-D.L.; Suzuki,-Y.; Garside,-C.; Ducklow,-H.W.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: NATURE. 1991. vol. 352, no. 6336, pp. 612-614
LA: English
ER: M (Marine)
AB: The authors directly observed rapid dissolved organic carbon (DOC) turnover by bacterioplankton during the spring phytoplankton bloom in the North Atlantic ocean. Potential turnover rates, measured in 0.8- mu m filtered samples, ranged from 0.025 to 0.363 per day, and were consistent with bacterial biomass production and uptake of dissolved nitrogen (NH super(+)@)d4, NO super(-)@)d3 and urea). Our results indirectly suggest that cycling of dissolved organic nitrogen (DON) differs from that of DOC. The high estimates of DOC concentrations and turnover rates repeated here, if found to be general, would seem to demand changes in models of carbon cycling and of the ocean's role in buffering increases in atmospheric CO sub(2).
AN: 2622122
1084 of 1521
TI: The accumulation of barium by marine phytoplankton grown in culture.
AU: Fisher,-N.S.; Guillard,-R.R.L.; Bankston,-D.C.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11794-5000, USA
SO: J.-MAR.-RES. 1991. vol. 49, no. 2, pp. 339-354
LA: English
ER: M (Marine)
AB: Phytoplankton have been implicated as potentially important vectors for the vertical transport of barium in the oceans. To better assess the extent to which phytoplankton can affect the geochemical cycling of barium, its bioconcentration was studied in 21 clones of marine phytoplankters belonging to 9 algal classes. Dinoflagellates and several other algae not only concentrated Ba to relatively high levels, they also accumulated Si when grown in Si-enriched medium, although they grew at least as well without added Si as with it. Ba and Si accumulation were generally negatively correlated.
AN: 2621532
1085 of 1521
TI: Development and assessment of an analytical system for the accurate and continual measurement of total dissolved inorganic carbon.
AU: Robinson,-C.; Williams,-P.J.-leB.
AF: University Coll. North Wales, Sch. Ocean Sci., Menai Bridge LL59 5EY, UK
SO: MAR.-CHEM. 1991. vol. 34, no. 3-4, pp. 157-175
LA: English
ER: M (Marine)
AB: An automated coulometric titration system based on that described by Johnson, Sieburth, Williams and Brandstrom (1987, Mar. Chem., 21: 117-133) has been evolved for the accurate and continual measurement of total dissolved inorganic carbon (TCO sub(2)). The instrument achieves an analytical precision (1 SD) of plus or minus 0.5-1.0 mu mol/kg (0.025-0.05%). The accuracy of the system has been examined by a limited comparison with other coulometric-based titrators and with a manometric-based system; agreement was to 1 mu mol/kg. The capability for automatic continual analysis allows surface mapping of TCO sub(2); a sample rate of 10 analyses/h gives a mapping resolution of 102 km. Provision for frequent standardization with a liquid substandard has been included in the development. The ability to achieve high-density analyses while maintaining interlaboratory consistency and standardization constitutes a vital contribution to surveys of ocean carbon chemistry (e.g. Joint Global Ocean Flux Study (JGOFS), World Ocean Circulation Experiment (WOCE)).
AN: 2620475
1086 of 1521
TI: Atmospheric deposition and nitrogen inputs to coastal waters.
AU: Hinga,-K.R.; Keller,-A.A.; Oviatt,-C.A.
AF: Mar. Ecosyst. Res. Lab., Grad. Sch. Oceanogr., Univ. Rhode Island, Narragansett, RI 02882, USA
SO: AMBIO. 1991. vol. 20, no. 6, pp. 256-260
LA: English
ER: M (Marine); B (Brackish)
AB: Recent reports have suggested that the fixed nitrogen which deposits from the atmosphere onto the watershed is a significant fraction of total anthropogenic loading of nitrogen to the Chesapeake Bay. A different approach was used here to estimate the atmospheric contribution of nitrogen to Narragansett Bay, the New York Bight, Ochlockonee Bay, Laholm Bay, and Chesapeake Bay. There is probably at least a factor of four uncertainty in loading estimates. The best estimates of the contribution of nitrogen reaching these ecosystems via emissions and deposition, relative to the total anthropogenic inputs of nitrogen, ranged from 11% to essentially 100%.
AN: 2618019
1087 of 1521
TI: Keystone species and mangrove forest dynamics: The influence of burrowing by crabs on soil nutrient status and forest productivity.
AU: Smith,-T.J.,III; Boto,-K.G.; Frusher,-S.D.; Giddins,-R.L.
AF: Rookery Bay Natl. Estuar. Res. Reserve, Florida Dep. Nat. Resour., 10 Shell Island Rd., Naples, FL 33962, USA
SO: ESTUAR.-COAST.-SHELF.-SCI. 1991. vol. 33, no. 5, pp. 419-432
LA: English
ER: M (Marine); B (Brackish)
AB: The density of the burrowing crab fauna in a mangrove forest was reduced, using pitfall traps, to test the hypothesis that decreased burrowing would lead to: increased soil sulphide concentrations; altered nutrient concentrations; and decreased forest productivity and growth. Experiments were conducted in Rhizophora -dominated forests in north Queensland, Australia, over a 12-month period. Crabs were trapped and removed from the experimental plots during 1 week each month for a year. Soil chemical and forest growth parameters were measured at monthly intervals in the experimental and appropriate control plots. Over the course of the experiment, soil sulphide and ammonium concentrations increased to levels which were significantly higher in plots from which crabs were being removed in comparison to controls.
AN: 2616466
1088 of 1521
TI: MASAS -- modelling of anthropogenic substances in aquatic systems on personal computers -- application to lakes.
AU: Ulrich,-M.; Schwarzenbach,-R.P.; Imboden,-D.M.
AF: Swiss Fed. Inst. Water Resour. and Water Pollut. Control (EAWAG), HC-8600 Duebendorf, Switzerland
SO: ENVIRON.-SOFTWARE. 1991. vol. 6, no. 1, pp. 34-38
LA: English
ER: F (Freshwater)
AB: MASAS is a computer simulation program for the evaluation of the dynamic behavior of anthropogenic organic micropollutants in aquatic systems, currently implemented for lakes. It allows a user to construct models of successively increasing complexity, and to build libraries with information for compounds and for lakes. Empirical and theoretical functions are included to approximate unknown parameters. The program is being implemented in Modula-2 as a user friendly tool for the Apple Macintosh personal computer. Availability: The program will be made available to interested persons/institutions (Diskette and User Manual) in fall 1990.
AN: 2615870
1089 of 1521
TI: Microbial processes affecting alanine and glutamic acid in anoxic marine sediments.
AU: Burdige,-D.
AF: Dep. Oceanogr., Old Dominion Univ., Norfolk, VA 23529-0276, USA
SO: FEMS-MICROBIOL.-ECOL. 1991. vol. 85, no. 3, pp. 211-232
LA: English
ER: M (Marine); B (Brackish)
AB: The utilization of glutamic acid and alanine in anoxic marine sediments was studied using sediments collected from a tidal flat on the Atlantic Ocean side of Virginia's Eastern Shore (Bordenstake Bay) and a site in the mid-Chesapeake Bay. The observations suggest that the general pathway of amino acid utilization in anoxic sediments involves their oxidation by fermentative bacteria to produce compounds such as volatile fatty acids or H sub(2) which are then themselves used as substrates by either sulfate reducing or methanogenic bacteria.
AN: 2615107
1090 of 1521
TI: Microbial degradation of methanesulphonic acid: A missing link in the biogeochemical sulphur cycle.
AU: Baker,-S.C.; Kelly,-D.P.; Murrell,-J.C.
AF: Dep. Biol. Sci., Univ. Warwick, Coventry CV4 7AL, UK
SO: NATURE. 1991. vol. 350, no. 6319, pp. 627-628
LA: English
AB: Atmospheric dimethyl sulphide, arising from marine algae, cyanobacteria and salt marsh plants such as Spartina , is the principal sulphur compound entering the atmosphere from terrestrial and aquatic environments. Methanesulphonic acid (CH sub(3)SO sub(3)H; MSA) has been identified as a major product of the photochemical oxidation in the atmosphere of dimethyl sulphide. Here we describe terrestrial bacteria that grow on MSA. Their activities in the natural environment would result in the mineralization of MSA to carbon dioxide and sulphate, thus completing our understanding of this part of the sulphur cycle.
AN: 2615059
1091 of 1521
TI: Contaminated marine sediments: Assessment and remediation.
AU: Swartz,-R.C.
CA: Environmental Protection Agency, Narragansett, RI (USA). Environmental Research Lab.
SO: ECOL.-RES.-SER.-U.S.-ENVIRON.-PROT.-AGENCY. 1990. 18 pp
NT: NTIS Order No.: PB91-132811/GAR. ERLN-N068.
RN: EPA/600/D-90/188 (EPA600D90188)
LA: English
ER: M (Marine)
AB: Sediment toxicity tests are part of several comprehensive methods for generating sediment quality criteria. Major research needs include test methods for chronic exposures, field validation of acute toxicity tests and the geochemical integrity of test materials, the relation between toxicity and the bioavailability/partitioning of contaminants in different sediment phases, models of toxicological interactions between sediment contaminants, and sediment wasteload allocation models. (Also publ. as Environmental Research Lab., Narragansett, RI., rept. no. CONTRIB-N068. Prepared in cooperation with National Research Council, Washington, DC. Marine Board.)
AN: 2613634
1092 of 1521
TI: Marine processes, their relationship to pollution, and a framework for waste management (chapter 1).
AU: Baumgartner,-D.J.; Duedall,-I.W.
CA: Environmental Protection Agency, Narragansett, RI (USA). Environmental Research Lab.
SO: ECOL.-RES.-SER.-U.S.-ENVIRON.-PROT.-AGENCY. 1990. 10 pp
NT: NTIS Order No.: PB91-132829/GAR. ERLN-N067.
RN: EPA/600/D-90/187 (EPA600D90187)
LA: English
ER: M (Marine)
AB: The transport and transformation processes which influence the way in which waste materials are dispersed and incorporated into the marine environment are reviewed and summarized as a preface for appreciation of the technical papers which follow in the volume. In a similar vein the papers are discussed in relation to an outline of a risk assessment framework which may be useful in guiding both regulatory action and future research. It is concluded that marine environmental process research has a role to play, but not an exclusive role in regulation. (Also pub. as Florida Inst. of Tech., Melbourne. rept. no. CONTRIB-139 and Environmental Research Lab., Narragansett, Newport, OR., Mark O. Hatfield Marine Science Center, rept. no. CONTRIB-N067. Pub. in Oceanic Processes in Marine Pollution Transformation, v6 Chapter 1, p3-11, 1990. Prepared in cooperation with Office of Technology Assessment, Washington, DC. Sponsored by Florida Inst. of Tech.)
AN: 2613628
1093 of 1521
TI: Flux and recycling of bioactive substances in the surface sediments of the deep basins off southern California: Progress report.
AU: Jahnke,-R.A.
CA: Scripps Inst. of Oceanography, San Diego, CA (USA)
SO: REP.-U.S.-DEP.-ENERGY. 1988. 10 pp
NT: NTIS Order No.: DE88007999/GAR.
RN: DOE/ER/60334-T1 (DOEER60334T1)
LA: English
AB: Goals of this project are to develop an understanding of the processes that recycling biogenic debris reaching the seafloor and to quantitatively determine the role of seafloor recycling in oceanic biogenic cycles. This includes evaluating the rate at which biogenic elements are released from the sediments due to organic matter decomposition as well as the rate at which certain biogenic elements are consumed in the sediments such as the consumption of O sub 2 by oxic respiration and NO sub 3/sup/minus/by dentrification. Benthic fluxes were estimated via the Bottom Lander. Results were combined with results from other West-coast researchers and a preliminary organic carbon budget for Santa Monica Basin was estimated. During the past year, benthic fluxes have been measured by a new in situ benthic chamber instrument and a shipboard incubation method. (Contract FG05-85ER60334. Portions illegible in microfiche.)
AN: 2613069
1094 of 1521
TI: Program of mineralization and cycling in marine systems: Organic geochemistry of particulates and sediments (CaBS): Progress report, November 15, 1987-November 14, 1988.
AU: Venkatesan,-M.I.; Kaplan,-I.R.
CA: California Univ., Los Angeles (USA)
SO: REP.-U.S.-DEP.-ENERGY. 1988. 14 pp
NT: NTIS Order No.: DE89005045/GAR.
RN: DOE/ER/60338-5 (DOEER603385)
LA: English
ER: M (Marine)
AB: The sources of organic carbon in southern California Bight derive from both terrestrial and marine regimes. The varied organic carbon sources can be reasonably delineated within limits by the organic geochemical approach of determining various characteristic biomarkers, as well as a variety of pollution indicators. The distributions of organic biomarker compounds are characteristic of marine algae, terrestrial vascular plants, bacteria, etc. Presence of specific biomarkers also indicate the occurrence of specific species (e.g., dinosterol specific of dinoflagellates). There are some pollution indicators which one can look for in the marine environment to trace their origin to terrestrial inputs, i.e., polycyclic aromatic hydrocarbons from petroleum and combustion coprostanol from sewage etc. (Contract FG05-85ER60338. Portions illegible in microfiche.)
AN: 2613036
1095 of 1521
TI: Scavenging retention of metals by zooplankton fecal pellets and marine snow.
AU: Fisher,-N.S.; Nolan,-C.V.; Fowler,-S.W.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11794-5000, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1991. vol. 38, no. 10A, pp. 1261-1275
LA: English
ER: M (Marine)
AB: The scavenging and retention of nine metals in different batches of zooplankton fecal pellets and marine snow were studied in the laboratory using radiotracer techniques. Dissolved super(60)Co, super(65)Zn, super(106)Ru, super(2109)Cd, super(110m)Ag, super(141)Ce, super(154)Eu, super(237)Pu and super(241)Am were scavenged from seawater onto euphausiid fecal pellets, marine snow and copepod fecal pellets recovered from sediment traps and onto copepod fecal pellets freshly produced in the laboratory. K sub(d) values for the different radioisotopes ranged from 8.4 x 10 super(2) to 1.9 x 10 super(5). The radiolabeled fecal pellets and marine snow, resuspended into unlabeled seawater at 2 and 15 degree C, displayed metal depuration curves generally conforming to a two-compartment model, with overall retention half-times (t sub(r1/2)s) varying with each metal and type of debris. Our results provide direct evidence that fecal pellets and marine snow can effectively scavenge metals from seawater; of the metals examined, zinc and cadmium are likely to be remineralized most rapidly in surface waters, while the others are likely to be vertically transported hundreds to thousands of meters.
AN: 2612499
1096 of 1521
TI: Sedimentation of pteropods in the Norwegian Sea in autumn.
AU: Bathmann,-U.V.; Noji,-T.T.; von-Bodungen,-B.
AF: Alfred-Wegener-Inst. Polar- und Meeresforsch., 2850 Bremerhaven, FRG
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1991. vol. 38, no. 10A, pp. 1341-1360
LA: English
ER: M (Marine)
AB: Pteropod vertical distribution on the Voering Plateau (Norwegian Sea) was recorded during a 3 week drifting experiment during August 1988. Parallel to sampling of hydrographical, chemical and biological properties of the water column, sediment traps recorded vertical pelagic flux at five depth strata. Pteropods (Limacina retroversa ) dominated the zooplankton and reached maximum values (> 13,600 individuals/m super(3)) in the upper 25 m of the water column; the size spectrum shifted from small (< 1 mm) towards large (> 3 mm) specimens during the study. Vertical flux at 100 m depth increased from 600 mg dry weight/m super(2)/day to 1000 mg dry weight/m super(2)/day at the end of the experiment. Trap material during the first sampling intervals consisted primarily of phytoplankton and protozoans aggregated within pteropod feeding nets. Through their feeding, reproduction and subsequent mortality pteropods were the main contributors to vertical particle flux in the eastern Norwegian Sea during 1988.
AN: 2612451
1097 of 1521
TI: Benthic organic carbon degradation and biogenic silica dissolution in the central equatorial Pacific.
AU: Martin,-W.R.; Bender,-M.; Leinen,-M.; Orchardo,-J.
AF: Dep. Chem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1991. vol. 38, no. 12A, pp. 1481-1516
LA: English
ER: M (Marine)
AB: Shipboard whole-core squeezing was used to measure pore water concentration vs depth profiles of NO sub(3)@)u-, O sub(2) and SiO sub(2) at 12 stations in the equatorial Pacific along a transect from 15 degree S to 11 degree N at 135 degree W. The NO sub(3)@)u- and SiO sub(2) profiles were combined with fine-scale resistivity and porosity measurements to calculate benthic fluxes. After using O sub(2) profiles, coupled with the NO sub(3)@)u- profiles, to constrain the C:N of the degrading organic matter, the NO sub(3)@)u- fluxes were converted to benthic organic carbon degradation rates. The range in benthic organic carbon degradation rates is 7-30 mu mol/cm super(2)/y, with maximum values at the equator and minimum values at the southern end of the transect. The zonal trend of benthic degradation rates, with its equatorial maximum and with elevated values skewed to the north of the equator, is similar to the pattern of primary production observed in the region. Benthic organic carbon degradation is 1-2% of primary production. The range of benthic biogenic silica dissolution rates is 6.9-20 mu mol/cm super(2)/y, representing 2.5-5% of silicon fixation in the surface ocean of the region. Its zonal pattern is distinctly different from that of organic carbon degradation.
AN: 2612410
1098 of 1521
TI: Seasonal uptake and regeneration of inorganic nitrogen and phosphorus in a large oligotrophic lake: Size-fractionation and antibiotic treatment.
AU: Dodds,-W.K.; Priscu,-J.C.; Ellis,-B.K.
AF: Div. Biol., Ackert Hall, Kansas State Univ., Manhattan, KS 66506, USA
SO: J.-PLANKTON-RES. 1991. vol. 13, no. 6, pp. 1339-1358
LA: English
ER: F (Freshwater)
AB: Uptake and regeneration of inorganic N and P in oligotrophic Flathead Lake (Montana, USA) were measured with super(15)N and super(32)P incorporation and dilution experiments, six times over a seasonal cycle. These results suggests that both N and P dynamics should be considered when examining nutrient regulation of primary productivity of oligotrophic lakes, bacteria probably compete with phytoplankton for both ammonium and phosphate, biotic regeneration is the main source of nutrients to the epilimnion during stratification, and crustacean zooplankton were relatively unimportant sources of regenerated ammonium and phosphate.
AN: 2612353
1099 of 1521
TI: Estimating organic P utilization by freshwater plankton using ( super(32)P)ATP.
AU: Bentzen,-E.; Taylor,-W.D.
AF: Dep. Biol., Univ. Waterloo, Waterloo, Ont. N2L 3G1, Canada
SO: J.-PLANKTON-RES. 1991. vol. 13, no. 6, pp. 1223-1238
LA: English
ER: F (Freshwater)
AB: The authors examined the use of ( super(32)P)ATP for the determination of dissolved organic phosphorus (DOP) utilization by freshwater plankton. Uptake of tracer amounts of super(32)P from ATP into different size classes of plankton demonstrated that the bacterial size fraction (0.2-1 mu m) dominates uptake, but this domination diminishes when DOP concentrations are elevated. ( super(32)P)ATP is an effective and convenient substrate for tracing DOP dynamics in a manner comparable to using super(32)PO sub(4) super(3-) to study PO sub(4) super(3-) dynamics.
AN: 2612271
1100 of 1521
TI: Accumulation and biological cycle of N and P elements in the Bruguiera sexangula mangrove forest in Hainan, China.
AU: Lin,-Peng; Wu,-Xinhua
AF: Dep. Biol., Xiamen Univ., Xiamen, People's Rep. China
SO: J.-XIAMEN-UNIV.-NAT.-SCI.-XIAMEN-DAXUE-XUEBAO. 1990. vol. 29, no. 4, pp. 463-467
LA: Chinese
ER: M (Marine)
AB: This paper deals mainly with the accumulation and biological cycle of N and P elements of 55-year-old Bruguiera sexangula community of Hainan Island, China. The amounts of N and P in the standing crop of this community were 1427.4 kg/ha and 165.7 kg/ha. In the biological cycle of N and P of this stand, the annual values of the vegetation mineral uptake were (kg/ha multiplied by yr) 190.0 for N and 24.1 for P. The turnover periods of N and P were 13 and 12 years respectively.
AN: 2611909
1101 of 1521
TI: Seasonal and depth-related changes in the source of sinking particles in the North Atlantic.
AU: Altabet,-M.A.; Deuser,-W.G.; Honjo,-S.; Stienen,-C.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: NATURE. 1991. vol. 354, no. 6349, pp. 136-139
LA: English
ER: M (Marine)
AB: Large, fast-sinking particles are important in the downward transport and redistribution of biogeochemical species in the deep ocean. Using nitrogen isotope ratio, super(15)N/ super(14)N, as an in situ tracer, we investigate the source and transformation of these particles in the North Atlantic ocean. We observe seasonal variations in delta super(15)N associated with seasonal changes in near-surface nitrate concentration and particle flux; the nitrogen isotope variations are consistent with, but much larger than, previously observed variability. Our results show that the signal from these near-surface changes propagates rapidly into the deep ocean, but is modified depending on the phase of the seasonal production cycle. Surprisingly, we find that delta super(15)N values of sinking particles decrease with depth during low-flux periods--behaviour that may occur generally in the open ocean. The sinking particles must therefore be either gaining light nitrogen or losing heavy nitrogen, an effect that we believe requires there to be another source of sinking particles, apart from recent surface production.
AN: 2611636
1102 of 1521
TI: An input/output flux for lead in a coastal bay off Alexandria region.
AU: Abdel-Moati,-A.R.
AF: Oceanogr. Dep., Fac. Sci., Alexandria Univ., Moharam Bay, Alexandria, Egypt
SO: WATER-AIR-SOIL-POLLUT. 1991. vol. 59, no. 3-4, pp. 261-269
LA: English
ER: M (Marine)
AB: During 1987, seawater, rain, dust and drainage water samples were collected from Abu-kir bay (360 km super(2)) east of Alexandria city to set up and evaluate the relative importance of different sources to the biogeochemical cycle of Pb in the bay. The mean total concentration of Pb in the bay water was 455 plus or minus 180 and 785 plus or minus 287 ng/kg during low and high flow periods, respectively. About 75 plus or minus 12% are in the particulate form. The bay receives annually about 8.12 plus or minus 2.18 and 6.13 plus or minus 1.06 t of Pb through agricultural and industrial discharge. In addition, 0.48 plus or minus 0.11 t/yr and 0.23 plus or minus 0.04 t/yr of Pb reaches the bay through wet and dry depositions, respectively. The outflowing surface water from the bay carries 15.4 plus or minus 3.6 t Pb/yr to the southeastern Mediterranean waters. Data from sedimentation traps indicated that the bulk sedimentation rate in the bay was 95 plus or minus 18 kg/yr elevating the concentrations of Pb in sediments to more than 64 mu g/g. The imbalance in the Pb flux (excess + 0.6 + 0.08 t) indicates Pb accumulation in the water column.
AN: 2606461
1103 of 1521
TI: Trace metal distribution in the coastal waters of Visakhapatnam.
AU: Prabhakaramurty,-P.V.S.; Satyanarayana,-D.
AF: Sch. Chem., Andhra Univ., Waltair, Visakhapatnam 530 003, India
SO: INDIAN-J.-ENVIRON.-PROT. 1990. vol. 10, no. 12, pp. 919-925
LA: English
ER: M (Marine)
AB: The concentration levels of dissolved and particulate trace metals (Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb) were determined in the coastal waters of Visakhapatnam, Andhra Pradesh, India, along 3 transects (Gangavaram, Harbour and Rushi Hill) at monthly intervals over a period of one year (September 1986 to August 1987). The results indicated distinct spatial and temporal variations in the study region. Dissolved and particulate fractions of Mn, Fe, Cu, Zn, Cd showed surface depletion and bottom enrichment due to their involvement in the biogeochemical cycle leading to their removal in surface and release at bottom waters. On the other hand, dissolved and particulate Pb recorded surface enrichment and bottom depletion due to anthropogenic atmospheric input. Comparison of concentration levels of trace metals obtained in the present study with earlier reports demonstrates the extent of pollution in the harbour and its impact on the coastal environment of Visakhapatnam.
AN: 2605976
1104 of 1521
TI: Phosphorus cycling by mussels (Unionidae: Bivalvia) in Lake St. Clair.
AU: Nalepa,-T.F.; Gardner,-W.S.; Malczyk,-J.M.
AF: Great Lakes Environ. Res. Lab., 2205 Commonwealth Blvd., Ann Arbor, MI 48105, USA
CO: Symp. on Environmental Assessment and Habitat Evaluation in the Upper Great Lakes Connecting Channels (at) 31. Conf. on Great Lakes Research, Hamilton, Ont. (Canada), 1988
SO: ENVIRONMENTAL-ASSESSMENT-AND-HABITAT-EVALUATION-OF-THE-UPPER-GREAT-LAKES-CONNECTING-CHANNELS. Munawar,-M.;Edsall,-T.-eds. 1991. vol. 219 pp. 229-250
ST: HYDROBIOLOGIA. vol. 219
LA: English
ER: F (Freshwater)
AB: The role of mussels in cycling phosphorus in Lake St. Clair, North America, during the May-Oct. period was examined by measuring concentrations in the water column and in mussel tissue, and by measuring rates of biodeposition and excretion. Mean rates of biodeposition and excretion for Lampsilis radiata siliquoidea , the most abundant species, were 6.3 mu g/P (g shell-free dry wt)/h and 1.3 mu g/P (g shell-free dry wt)/h, respectively; body tissue phosphorus content was 2.7 percent of dry wt. Seasonal changes in excretion rates appeared to be related to the gametogenic cycle of the organism, but seasonal changes in biodeposition rates were not apparent. Phosphorus assimilation efficiency for this species was about 40 percent. Overall, the mussel population in Lake St. Clair filtered about 21 MT of phosphorus, or about 13.5 percent of the total phosphorus load for the May-Oct. study period. Of this amount, about 134 MT was sedimented to the bottom via biodeposition. Mussel biodeposition may be an important source of nutrients to other biotic components in the lake such as macrophytes and invertebrate deposit-feeders.
AN: 2603326
1105 of 1521
TI: Chloride cycling in two forested lake watersheds in the west-central Adirondack Mountains, New York, U.S.A.
AU: Peters,-N.E.
AF: U.S. Geol. Surv., 6481-B Peachtree Industrial Blvd., WRD, Doraville, GA 30360, USA
SO: WATER-AIR-SOIL-POLLUT. 1991. vol. 59, no. 3-4, pp. 201-215
LA: English
ER: F (Freshwater)
AB: The chemistry of precipitation, throughfall, soil water, ground water, and surface water was evaluated in two forested lake-watersheds over a 4-yr period to assess factors controlling Cl super(-) cycling. Results indicate that Cl super(-) cycling in these watersheds is more complex than the generally held view of the rapid transport of atmospherically derived Cl super(-) through the excosystem. The annual throughfall Cl super(-) flux for individual species in the northern hardwood forest was 2 to 5 times that of precipitation (56 eq/ha), whereas the Na super(+) throughfall flux, in general, was similar to the precipitation flux. Concentrations of soil-water Cl super(-) sampled from ceramic tension lysimeters at 20 cm below land surface generally exceeded the Na super(+) concentrations and averaged 31 mu eq/L, the highest of any waters sampled in the watersheds, except throughfall under red spruce which averaged 34 mu eq/L. Chloride was concentrated prior to storms and mobilized rapidly during storms as suggested by increases in streamwater Cl super(-) concentrations with increasing flow.
AN: 2603287
1106 of 1521
TI: Empirical methods in the design of groundwater quality monitoring strategies.
AU: Rajagopal,-R.
AF: Dep. Geogr., 302 Jessup Hall, Univ. Iowa, Iowa City, IA 52242, USA
CO: Natl. Conf. on Hydraulic Engineering, New Orleans, LA (USA), 14-18 Aug 1989
SO: HYDRAULIC-ENGINEERING.-PROCEEDINGS-OF-THE-1989-NATIONAL-CONFERENCE-ON-HYDRAULIC-ENGINEERING. Ports,-M.A.-ed. 1989. pp. 416-421
LA: English
ER: F (Freshwater)
AB: Ground-water quality monitoring strategies are designed for environments ranging from the most complex to the very simple. Complexity is characterized by socio-economic, public health, and biogeochemical interactions in space and time. Arguments are offered to show that empirical methods are cost-effective for the more complex, while process-based methods are appropriate for the relatively simpler environments.
AN: 2603251
1107 of 1521
TI: Lipids of cultured Phaeocystis pouchetii : Signatures for food-web, biogeochemical and environmental studies in Antarctica and the Southern Ocean.
AU: Nichols,-P.D.; Skerratt,-J.H.; Davidson,-A.; Burton,-H.; McMeekin,-T.A.
AF: CSIRO Div. Oceanogr., G.P.O. Box 1538, Hobart, Tas. 7001, Australia
SO: PHYTOCHEMISTRY. 1991. vol. 30, no. 10, pp. 3209-3214
LA: English
ER: M (Marine)
AB: The lipid, fatty acid, sterol and pigment composition of cultured Phaeocystis pouchetii were analysed by capillary GC, GC-MS, TLC-FID and HPLC. Polar lipids were the dominant class. Significant variation occurred between strains in the amount of lipid per cell; lipid content varied from 3.5 pg/cell for the axenic spherical colony forming strain A1-3, to 8.2 pg/cell for the largely flagellate strain DE10 and 7.7 pg/cell for the benthic strain. The dominant sterol was 24-methylcholesta-5,22E-dien-3 beta -ol irrespective of culture age or life stage composition. The major fatty acids for strain A1-3 were: 16:0, 18:1 omega 9c, 14:0 and 18:0, while profiles for strains DE10 and A1-4 contained 14:0, 16:0, 18:1 omega 9c and 18:0. The essential fatty acids 20:5 omega 3 and 22:6 omega 3 were only minor or trace components, demonstrating the poor nutritional quality (with respect to fatty acids) of Phaeocystis to Antarctic grazers. However, the lipid and fatty acid content of the strains indicate that the flagellate stage is of greater nutritional value than the free floating colonies, and that the flagellate and benthic colonial stages are most biochemically alike. The major pigments in all strains were chlorophylls a and c and 19'-hexanoyloxyfucoxanthin. Minor carotenoids detected were 19'-butanoyloxyfucoxanthin, fucoxanthin, diadinoxanthin and diatoxanthin.
AN: 2601006
1108 of 1521
TI: The distribution of dissolved DNA in an oligotrophic and a eutrophic river of Southwest Florida.
AU: Paul,-J.H.; Cazares,-L.H.; David,-A.W.; DeFlaun,-M.F.; Jeffrey,-W.H.
AF: Dep. Mar. Sci., Univ. South Florida, 140 7th Ave. S., St. Petersburg, FL 33701, USA
SO: HYDROBIOLOGIA. 1991. vol. 218, no. 1, pp. 53-63
LA: English
ER: F (Freshwater)
AB: The distribution of dissolved DNA concentrations and some microbial variables were compared in an oligo-mesotrophic river (the Crystal River) and a phosphate-rich eutrophic river (the Alafia River) in Southwest Florida over a 15-mo. period. The greatest concentrations of dissolved DNA in the Alafia River were found in areas that contained the largest populations of phytoplankton and bacteria. Differences in dissolved DNA concentrations between these environments and more pristine environments were of the same order of magnitude (1.8 to 2.2-fold) as the differences in bacterial abundance and activity, but considerably less than differences in phytoplankton abundance and activity between such environments. Results suggest that: 1) in situ planktonic activity is a greater source of dissolved DNA than allochthonous or terrestrial sources of DOC; 2) factors that control the magnitude of heterotrophic bacterial populations are more likely to control dissolved DNA levels than factors regulating autotrophic population activity and abundance; 3) differences in dissolved DNA between eutrophic and oligo-mesotrophic environments are often much smaller than the differences in nutrient concentration between such environments.
AN: 2600452
1109 of 1521
TI: Circulation and exchange processes on the South Atlantic Bight continental shelf: Progress report, July 1, 1988 to June 30, 1989.
AU: Lee,-T.N.
CA: Miami Univ., FL (USA). Rosenstiel Sch. of Marine and Atmospheric Sciences
SO: REP.-U.S.-DEP.-ENERGY. 1989. 51 pp
NT: NTIS Order No.: DE89010065/GAR. Contract FG05-85ER60355.
RN: DOE/ER/60355-4 (DOEER603554)
LA: English
ER: M (Marine)
AB: The work Department of Energy sponsored Southeast US Continental Shelf program is a coordinated, multi-university, interdisciplinary investigation aimed at understanding the physical, chemical and biological processes in the South Atlantic Bight (SAB: east coast continental shelf region from Cape hatteras to Cape Canaveral). The activities of the other Program Investigators are discussed. The University of Miami component of the program involves an investigation of the physical processes regulating the transport and exchange of materials in the shelf waters. The guiding scientific objective of this work is to improve the capability for prediction of the physical environment. The principal scientific task is to determine the relative importance of the forces driving shelf circulation and exchange and to measure the shelf waters' response over variable time and space scales. The influence of physical processes on chemical and biological distributions and their interactions is studied through interdisciplinary investigations, joint analysis and interpretation of data and joint publications.
AN: 2600361
1110 of 1521
TI: Relationships between seepage chemistry and flow path through the near-shore sediments of an acidic lake.
AU: Schafran,-G.C.; Driscoll,-C.T.
AF: Dep. Civil Eng., Old Dominion Univ., Norfolk, VA 23529, USA
CO: 23. Congress in New Zealand, (Hamilton (New Zealand)), 8 Feb 1987
SO: CONGRESS-IN-NEW-ZEALAND-1987.-PROCEEDINGS. Sladecek,-V.-ed. 1988. vol. 23, no. 4 pp. 2262-2266
ST: VERH.-INT.-VER.-THEOR.-ANGEW.-LIMNOL.-PROC.-INT.-ASSOC.-THEOR.-APPL.-LIMNOL.-TRAV.-ASSOC.-INT.-LIMNOL.-THEOR.-APPL. vol. 23, no. 4
LA: English
ER: F (Freshwater)
AB: It was the focus of this study to investigate the variation of ground water inputs in the near-shore region of an acid lake and to assess the biogeochemical processes occurring within the near-shore sediments that influence seepage chemistry. Dart's Lake in the Adirondack Mountain region of New York State, U.S.A., was the site of this investigation. These results indicate that seepage chemistry is highly dependent on the flow path and is consistent with earlier studies that reported the importance of the hydrologic pathway in controlling groundwater chemistry.
AN: 2595876
1111 of 1521
TI: Radium accumulation from water by foliage of the water lily, Nymphaea violacea .
AU: Twining,-J.R.
AF: Environ. Sci. Div., Aust. Nucl. Sci. and Technol. Organ, Lucas Heights Res. Lab., Lock Mail Bag No. 1, Menai, N.S.W. 2234, Australia
CO: (23.) Congress in New Zealand, (Hamilton (New Zealand)), 8 Feb 1987
SO: CONGRESS-IN-NEW-ZEALAND-1987.-PROCEEDINGS. Sladecek,-V.-ed. 1988. vol. 23, no. 4 pp. 1954-1962
ST: VERH.-INT.-VER.-THEOR.-ANGEW.-LIMNOL.-PROC.-INT.-ASSOC.-THEOR.-APPL.-LIMNOL.-TRAV.-ASSOC.-INT.-LIMNOL.-THEOR.-APPL. vol. 23, no. 4
LA: English
ER: F (Freshwater)
AB: Radium-226 is a possible contaminant from the Ranger Uranium Mine at Jabiru, 240 km east of Darwin, in the Northern Territory of Australia. The Magela Creek floodplain, 10 km downstream supports large populations of Nymphaea violacea during the period of inundation from Dec to Jun. The plant is important because it is a traditional food of aboriginal people has a possible role in the biogeochemical cycling of radium. This work set out to assess the rates and extent of uptake and loss of radium by the foliage of N. violacea under laboratory conditions and to identify parameters likely to influence accumulation.
AN: 2595431
1112 of 1521
TI: The global beryllium 10 cycle.
AU: McHargue,-L.R.; Damon,-P.E.
AF: NSF-Arizona Facil. Radioisot. Anal., Dep. Geosci., Univ. Arizona, Tucson, AZ 85721, USA
SO: REV.-GEOPHYS. 1991. vol. 29, no. 2, pp. 141-158
LA: English
AB: The cosmogenic radionuclide super(10)Be has generated much interest because of its potential as a tracer in the environment and applications to geology, archaeology, glaciology, and oceanography. Nevertheless, for super(10)Be to be useful as a tool in the Earth sciences its geochemical cycle as outlined below needs to be understood more fully. Beryllium 10 (t sub(1/2) = 1.5 x 10 super(6) years) is mainly produced in the atmosphere by spallation of oxygen and nitrogen induced by secondary neutrons formed by cosmic ray interactions with the atmosphere, but some is produced in situ on the surface of the Earth. Deposition of super(10)Be onto the surface of the Earth depends primarily on precipitation. Deposited super(10)Be is made up of several components, primarily super(10)Be produced in the stratosphere and in the troposphere and super(10)Be recycled from dust and soil particles, and secondarily super(10)Be recycled from the ocean as hygroscopic nuclei and from cosmic dust.
AN: 2594273
1113 of 1521
TI: Molecular biology in studies of ocean processes.
AU: Falkowski,-P.G.; LaRoche,-J.
AF: Oceanogr. and Atmos. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: INT.-REV.-CYTOL. 1991. vol. 128, pp. 261-304
LA: English
ER: M (Marine)
AB: The authors describe potential applications of molecular biological techniques to study specific biological oceanographic processes. Molecular techniques are particularly useful and undoubtedly will continue to be used to understand the evolution of organisms, gene flow, and population genetics, and to construct phylogenetic trees. They also suggest the potential application of molecular techniques to understanding molecular mechanisms of key biogeochemical processes, such as nitrification, carbon fixation, silica incorporation, and iron limitation. While an understanding of mechanisms may not provide quantitative rate information, which is often desired by oceanographers, it provides a basis for understanding how physical and chemical ocean environments are related to complex biological phenomena.
AN: 2594223
1114 of 1521
TI: An integrated watershed/plot-scale study of element cycling in spruce ecosystems of the Black Forest.
AU: Feger,-K.-H.; Grahmer,-G.; Zoettl,-H.W.
AF: Inst. Soil Sci. and Forest Nutr., Albert-Ludwigs-Univ., Bertoldstr. 17, D-7800 Freiburg i.Br., FRG
CO: Int. Symp. on Management of Nutrition in Forests Under Stress, Freiburg (FRG), 18-21 Sep 1989
SO: WATER-AIR-SOIL-POLLUT. 1990. vol. 54, no. special, pp. 545-560
LA: English
ER: F (Freshwater)
AB: The research project ARINUS is the study of the effects of restabilization measures (fertilization with rapidly soluble Mg salts) and atmospheric deposition on the element cycling of typical spruce ecosystems in the Black Forest. The objective is to quantify the natural and anthropogenic components of element cycling at these sites which will provide a better estimation of the effects induced by external perturbations, e.g. increasing atmospheric deposition, fertilization, or biomass export. Interrelations between the terrestrial and aquatic system are assessed using an integrated approach which combines flux measurements in representative plots with balances of small experimental watersheds. This paper describes the approach, treatments, field installations, methods, and site conditions of one of the two research areas.
AN: 2591051
1115 of 1521
TI: Estimation of new production in the ocean by compound remote sensing.
AU: Sathyendranath,-S.; Platt,-T.; Horne,-E.P.W.; Harrison,-W.C.; Ulloa,-O.; Outerbridge,-R.; Hoepffner,-N.
AF: Biol. Oceanogr. Div., Bedford Inst. Oceanogr., Box 1006, Darmouth, N.S. B2Y 4A2, Canada
SO: NATURE. 1991. vol. 353, no. 6340, pp. 129-133
LA: English
ER: M (Marine)
AB: Oceanic new production can be estimated from remotely sensed data on ocean colour and temperature. This approach, which depends on parameterizations developed from ship observations, as well as on satellite data, yields more representative estimates of the large-scale average new production than those calculated from ship data alone.
AN: 2581899
1116 of 1521
TI: Do upper-ocean sediment traps provide an accurate record of particle flux?.
AU: Buesseler,-K.O.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: NATURE. 1991. vol. 353, no. 6343, pp. 420-423
LA: English
ER: M (Marine)
AB: Sediment traps are widely used to measure the vertical flux of particulate matter in the oceans. In the upper ocean, sediment traps have been used to determine the extent to which CO sub(2) fixed by primary producers is exported as particulate organic carbon. In addition, the observed decrease of particle flux with depth has been use to predict regeneration rates of organic matter and associated elements. Over seasonal or annual timescales, the import of limiting nutrients into the upper ocean (new production) should be balanced by particle export. Given the importance of accurately determining the sinking particle flux, it has been suggested that super(234)Th might be used to "calibrate" shallow-trap fluxes. The author presents a re-evaluation of existing super(234)Th data which indicates that trap-derived and model-derived super(234)Th particle fluxes can differ by a factor of plus or minus 3-10, suggesting that shallow traps may not provide an accurate measure of particle fluxes.
AN: 2580752
1117 of 1521
TI: Some aspects of deep-sea microbiology with emphasis on the environment of the Southern Ocean.
AU: Helmke,-E.; Weyland,-H.
AF: Alfred-Wegener-Inst. Polar and Mar. Res., Bremerhaven, FRG
CO: 2. Int. Marine Biotechnology Conf. (IMBC '91), Baltimore, MD (USA), 13-16 Oct 1991
SO: PROGRAM-AND-ABSTRACTS.-SECOND-INTERNATIONAL-MARINE-BIOTECHNOLOGY-CONFERENCE-IMBC-'-91. 1991. p. 73
NT: Abstract only.
LA: English
ER: M (Marine)
AB: Although our knowledge about deep-sea and especially about deep-sea adapted barophilic bacteria has increased significantly in the last ten years, the role and importance of these organisms in the food web and biogeochemical cycles as well as the linkage of psychrophilism and barophilism is not yet clear. The Southern Ocean with low temperatures throughout the entire water column proved to be an ideal area for studying these questions. Using a variety of methodological approaches employing both water and sediment samples considerable information was collected to support the idea that cold adapted barophilic bacteria are functionally dominant, at least in the abyssal zone. On the other hand cold adapted bacteria from the surface area were found to be extremely pressure sensitive.
AN: 2579804
1118 of 1521
TI: Aragonite and magnesian calcite fluxes to the deep Sargasso Sea.
AU: Fabry,-V.J.; Deuser,-W.G.
AF: Int. Lab. Mar. Radioact., 19 Ave. des Castellans, MC-98000, Monaco
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1991. vol. 38, no. 6A, pp. 713-728
LA: English
ER: M (Marine)
AB: Aragonite and magnesian calcite fluxes were estimated from a 14-month series of sediment trap samples from depths of 500, 1500 and 3200 m in the Sargasso Sea. No significant difference with depth was observed in fluxes of either carbonate phase. At 3200 m, the mean aragonite flux was 2.8 mg/m super(2)/day, or 13% of the total CaCO sub(3) flux. At all depths pteropods were the major source of aragonite, contributing more carbonate than heteropods by a factor of 3-24. Most of the pteropod aragonite occurred in the size fraction > 0.5 mm. At 3200 m, more than half of the pteropod mass flux in the size fraction > 0.5 mm comprised four species: Styliola subula, Clio pyramidata, Limacina inflata) and Cuvierina columnella . The mean magnesian calcite flux at 3200 m was 1.7 mg/m super(2)/day, or 8% of the total CaCO sub(3) flux. The majority of the magnesian calcite (9-12 mole % MgCO sub(3)) occurred in the finest size fraction, < 37 mu m. Evidence suggests that bryozoans attached to floating Sargassum) are the source of this magnesian calcite. The combined fluxes of aragonite and magnesian calcite accounted for 21-25% of the mean annual CaCO sub(3) flux to 1500 and 3200 m.
AN: 2579704
1119 of 1521
TI: Heterotrophic bacterial activity and growth rates in sediments of the continental margin of eastern Australia.
AU: Moriarty,-D.J.W.; Skyring,-G.W.; O'-Brien,-G.W.; Heggie,-D.T.
AF: CSIRO, Div. Fish., P.O. Box 120, Cleveland, Qld. 4163, Australia
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1991. vol. 38, no. 6A, pp. 693-712
LA: English
ER: M (Marine)
AB: The numbers, growth rates and productivity of heterotrophic bacteria were determined in sediment cores collected on the East Australian continental margin (28 and 32 degree S) at water depths ranging from 150 to 1000 m. The study was centered on a zone of modern phosphate nodule formation (350-460 m water depth), as bacteria had previously been implicated in the genesis of the modern phosphorites in this area. About 80% of bacterial productivity occurred in the upper 2 cm of sediment, although bacteria found at depths up to 70 cm in the sediment were capable of metabolic activity. Rates of phospholipid and protein synthesis were also determined and, when converted to productivity, the values in the upper 2 cm of sediment were mostly within a factor of 2 or 3 of values determined from DNA synthesis. Similar values were obtained for the flux of the organic carbon into the sediments, required to support metabolic activity, whether calculated from values for bacterial productivity or from a geochemical model of oxygen diffusion and consumption, using profiles of oxygen concentration in the sediments.
AN: 2579667
1120 of 1521
TI: Three-dimensional modeling of the global atmospheric sulfur cycle: A first step.
AU: Erickson,-D.J.,III; Walton,-J.J.; Ghan,-S.J.; Penner,-J.E.
AF: Scripps Inst. Oceanogr., A-024, La Jolla, CA 92093, USA
CO: Symp. on Global Climatic Effects of Aerosols, Reno, NV (USA), 11-13 Oct 1989
SO: ATMOS.-ENVIRON.,-PART-A. 1991. vol. 25A, no. 11, pp. 2513-2520
LA: English
ER: M (Marine)
AB: Atmospheric sulfur is known to be a major source of condensation nuclei (CN). Over continents the major source of sulfur is believed to be SO sub(2) emitted from industrial regions. Over remote marine regions, emission of biogenic dimethylsulfide (DMS) from the ocean surface is thought to be the major source of non-sea-salt sulfate and of CN. Here researchers apply a global three-dimensional model with a simplified treatment of the atmospheric sulfur cycle to address the question of whether anthropogenic sulfur transported from continents might impact marine CN concentrations over a significant fraction of the world's oceans. Processes treated in the model include transport, convective and eddy mixing, a simplified treatment of the conversion of SO sub(2) and DMS to form the condensate SO sub(4)@) super(2)- )removal of SO sub(2) and SO sub(4)@) super(2)-b)y dry deposition and wet deposition of SO sub(4)@) super(2)- )
AN: 2578904
1121 of 1521
TI: Geophysiology of natural marine sulfate aerosols.
AU: Anderson,-T.L.; Charlson,-R.J.
AF: Dep. Atmos. Sci., Univ. Washington, Seattle, WA 98195, USA
CO: Symp. on Global Climatic Effects of Aerosols, Reno, NV (USA), 11-13 Oct 1989
SO: ATMOS.-ENVIRON.,-PART-A. 1991. vol. 25A, no. 11, pp. 2445-2447
LA: English
ER: M (Marine)
AB: The hypothesis suggesting dimethyl sulfide (DMS) from oceanic phytoplankton as the dominant natural worldwide source of cloud condensation nuclei (CCN) is being tested in several ways. Studies ranging from the perturbation of cloud albedo by ship plumes to the sulfur content of Antarctic ice cores have revealed much about the working of the natural marine sulfur cycle and the mass flux of DMS-derived sulfur compounds. However, quantifying the relationship between DMS mass flux, or sulfate mass concentration, and CCN number remains as a major challenge.
AN: 2578834
1122 of 1521
TI: Aerosol formation during photooxidation of organosulfur species.
AU: Kreidenweis,-S.M.; Yin,-F.-D.; Wang,-S.-C.; Grosjean,-D.; Flagan,-R.C.; Seinfeld,-J.H.
AF: Dep. Chem. Eng., San Jose State Univ., San Jose, CA 95192, USA
CO: Symp. on Global Climatic Effects of Aerosols, Reno, NV (USA), 11-13 Oct 1989
SO: ATMOS.-ENVIRON.,-PART-A. 1991. vol. 25A, no. 11, pp. 2491-2500
LA: English
ER: M (Marine)
AB: The most abundant marine organosulfur species is dimethylsulfide (DMS), with an estimated overall flux from the world oceans of 40 plus or minus 20 Tg S/yr. This flux is a significant fraction of the global biogenic S emissions, and an understanding of the atmospheric chemistry of reduced sulfur compounds, including DMS and dimethyldisulfide (DMDS), is needed to evaluate their role in the global S budget. Measurements of aerosol formation during the photooxidation of DMS and DMDS in an outdoor smog chamber are compared with predictions from a model of aerosol nucleation and growth in the chemically reacting system. The aerosol is assumed to consist of methanesulfonic acid (MSA), sulfuric acid, and water. Source rates of the two acid species are obtained from a detailed chemical mechanism for the organosulfur precursor oxidation and are used to drive the aerosol model. Good agreement between experiment and predictions was observed for DMDS and DMS oxidation in the presence of NO sub(x), but maximum total number concentrations achieved during DMDS oxidation in the absence of NO sub(x) were somewhat underpredicted. The effect upon model predictions of variations in model input parameters is evaluated.
AN: 2578774
1123 of 1521
TI: Derivation and analysis of flow networks for open ocean plankton systems.
AU: Ducklow,-H.W.; Fasham,-M.J.R.; Vezina,-A.F.
AF: Horn Point Environ. Lab., Box 775, Cambridge, MD 21601, USA
SO: NETWORK-ANALYSIS-IN-MARINE-ECOLOGY.-METHODS-AND-APPLICATIONS. Wulff,-F.;Field,-J.G.;Mann,-K.H.-eds. 1989. vol. 32 pp. 159-205
ST: COAST.-ESTUAR.-STUD. vol. 32
LA: English
AB: Details are given of the production of an open ocean flow network, which could include a realistic depiction of a foodweb. Two complementary approaches were used to derive models of flow networks: an a priori steady state input-output flow analysis and an inverse approach. The results of analyses of network structure, Lindeman Trophic Aggregations and biogeochemical cycles are discussed.
AN: 2577862
1124 of 1521
TI: Separation of runoff components in a small mountainous watershed using stream solute data.
AU: Hirata,-T.; Muraoka,-K.
AF: Natl. Inst. Environ. Stud., Onogawa 16-2, Tsukuba, Ibaraki 305, Japan
CO: (23.) Congress in New Zealand, (Hamilton (New Zealand)), 8 Feb 1987
SO: CONGRESS-IN-NEW-ZEALAND-1987.-PROCEEDINGS. Sladecek,-V.-ed. 1988. vol. 23, no. 3 pp. 1354-1361
ST: VERH.-INT.-VER.-THEOR.-ANGEW.-LIMNOL.-PROC.-INT.-ASSOC.-THEOR.-APPL.-LIMNOL.-TRAV.-ASSOC.-INT.-LIMNOL.-THEOR.-APPL. vol. 23, no. 3
LA: English
ER: F (Freshwater)
AB: This study presented streamwater chemistry results obtained in the Tsukuba experimental forested basin, a basin designed to provide a basic understanding of nutrient dynamics in forest ecosystems. Rainfall, groundwater and streamwater were investigated since September 1984. On the basis of the observed data, the responses of the dissolved materials in the streamwater chemistry to the rainfall were used to examine runoff sources. Further contributors to the streamwater during rainfall events are examined by the use of runoff separation with an environmental tracer.
AN: 2575837
1125 of 1521
TI: Riparian zone as a source of phosphorus for a groundwater-dominated lake.
AU: Vanek,-V.
AF: Dep. Ecol.-Limnol., Univ. Lund, P.O. Box 65, S-221 00 Lund, Sweden
SO: WATER-RES. 1991. vol. 25, no. 4, pp. 409-418
LA: English
ER: F (Freshwater)
AB: Groundwater entering Lake Bysjoen in southern Sweden is somewhat higher in specific conductance and up to 20 times higher in phosphate than the mean for the lake. This leads to elevated values of both specific conductance and phosphate in lake water within a 500 m long and several meter wide strip along the shore. In areas not influenced by groundwater inflow, specific conductance and phosphorus content near the shore are close to that of open lake water. High concentrations of phosphate (up to 9 mg/l PO sub(4)-P) in the inflowing groundwater originate from the riparian zone surrounding the lake. It is suggested that, over a long time, this ecotone has accumulated phosphorus and other nutrients that were transported from the adjacent developed areas and arable land. This phosphorus is now entering the lake, probably as a result of increased decomposition of organic matter.
AN: 2574769
1126 of 1521
TI: Production and major nutrient composition of three grass species on the Magela floodplain, Northern Territory, Australia.
AU: Finlayson,-C.M.
AF: Alligator Rivers Reg. Res. Inst., Off. Superv. Sci., Post Off., Jabiru, N.T. 0886, Australia
SO: AQUAT.-BOT. 1991. vol. 41, no. 4, pp. 263-280
LA: English
ER: F (Freshwater)
AB: Seasonal changes in dry weights and nutrient concentrations in three aquatic grasses on the seasonally inundated Magela floodplain in northern Australia were investigated over an 18 month period. The dry weight of the aquatic grass species Pseudoraphis spinescens, Hymenachne acutigluma and Oryza meridionalis varied with water depth on the floodplain. Maximum dry weights occurred at the end of the wet season when water depth was decreasing. The perennial species P. spinescens and H. acutigluma had two growth periods and an annual productivity of 1.91 plus or minus 0.26 kg m super(-2) and 2.09 plus or minus 0.36 kg m super(-2), respectively, compared with 0.51 plus or minus 0.10 kg m super(-2) for the annual O. meridionalis . Relative to other aquatic and wetland plant species, the former two grasses have high production rates. The major nutrients nitrogen, phosphorus, sulphur, chloride, magnesium, calcium, sodium and potassium were generally present in low concentrations compared with concentrations in other plant species.
AN: 2573255
1127 of 1521
TI: Role of mangrove in mercury cycling and removal in the Jiulong Estuary.
AU: Lin,-Peng; Chen,-Ronghua
AF: Biol. Dep., Xiamen Univ., Xiamen 361005, People's Rep. China
SO: ACTA-OCEANOL.-SIN.-HAIYANG-XUEBAO. 1990. vol. 9, no. 4, pp. 622-624
LA: English
ER: M (Marine); B (Brackish)
AN: 2573005
1128 of 1521
TI: Methylation of inorganic selenium compounds by freshwater green algae, Ankistrodesums sp., Chlorella vulgaris and Selenastrum sp.
AU: Oyamada,-N.; Takahashi,-G.; Ishizaki,-M.
AF: Ibaraki Hyg. Lab., 4-1 Atago-cho, Mito 310, Japan
SO: EISEI-KAGAKU. 1991. vol. 37, no. 2, pp. 83-88
LA: English
ER: F (Freshwater)
AB: Biomethylation of selenium (Se) by freshwater green algae, Ankistrodesmus sp., Chlorella vulgaris and Selenastrum sp., which had been isolated from the Tone River and Lake Kasumigaura in Japan, were investigated. All of the three algae produced methylated Se compounds from the corresponding inorganic compounds. The formation of trimethylselenonium ion (TMSe) by algae reached a plateau 2-4 d after culturing and the amount of Se and TMSe was less than about 0.001% of the added Se. TMSe was also found in the algae and was in the range from 0.04 to 0.3% of total-Se accumulated in the algae. Green algae in the freshwater ecosystems might be related to methylation of Se, and biomethylation of Se by green algae is thought to be one of detoxification processes.
AN: 2572955
1129 of 1521
TI: Program of mineralization and cycling in marine systems: Organic geochemistry of particulates and sediments (CaBS): Technical progress report, November 15, 1988-May 14, 1989.
AU: Venkatesan,-M.I.; Kaplan,-I.R.
CA: California Univ., Los Angeles (USA)
SO: REP.-U.S.-DEP.-ENERGY. 1989. 3 pp
NT: NTIS Order No.: DE89015809/GAR. Contract FG05-85ER60338.
RN: DOE/ER/60338-7 (DOEER603387)
LA: English
ER: M (Marine)
AB: The principal objective of the current on-going project is to understand the processes involved in the cycling of organic carbon in the southern California Bight. This involves the evaluation of the relative flux of planktonic carbon to the seafloor versus the import of terrestrial carbon components and the determination of the rate of decomposition of sedimenting organic matter in the water column. These goals were achieved by the chemical characterization of sedimenting particles (from traps) as well as in the near surface sediments. The organic matter in the marine regime comprises contribution from land plants, marine productivity (plankton and bacteria) as well as anthropogenic sources. At UCLA, researchers have been focusing on the chemical characterization of selected classes of organic carbon compounds derived from these various sources to understand the vertical flux and the chemical composition of the particulate organic matter which are controlled by complex transport, transformation, degradation and remineralization processes.
AN: 2570874
1130 of 1521
TI: The mineralization of chitin in the sediments of the Ythan Estuary, Aberdeenshire, Scotland.
AU: Hillman,-K.; Gooday,-G.W.; Prosser,-J.I.
AF: Rowett Res. Inst., Greenburn Rd., Bucksburn, Aberdeen AB2 9SB, UK
SO: ESTUAR.-COAST.-SHELF-SCI. 1989. vol. 29, no. 6, pp. 601-612
LA: English
ER: M (Marine)
AB: Reliable methods have been developed for the quantitative estimation of chitin, chitosan and chitin deacetylase in sediment samples, as well as two methods for the estimation of chitinase in these samples. The differing substrates used in the latter two methods have produced distinct "depth profiles" for chitinase activity which suggest the presence of more than one chitinolytic system in the sediments of the Ythan estuary. Studies on the mineralization of chitin in these sediments have revealed a complex system with a number of unexpected features. The rate of chitin degradation was reduced in late summer, possibly due to the heavy seaweed growth which covers the mud flats at this time, although the potential degradative activities of the enzymes chitinase and chitin deacetylase were higher in summer than in winter.
AN: 2567946
1131 of 1521
TI: (Bio)geochemical reactions in aquifer material from a thermal energy storage site.
AU: Brons,-H.J.; Griffioen,-J.; Appelo,-C.A.J.; Zehnder,-A.J.B.
AF: Dep. Microbiol., Wageningen Agric. Univ., Hesselink van Suchtelenweg 4, 6703 CT Wageningen, Netherlands
SO: WATER-RES. 1991. vol. 25, no. 6, pp. 729-736
LA: English
AB: The mobilization of organic compounds and the release of CO sub(2) was studied in aquifer material from a site chosen for thermal energy storage (ETS). These processes have been measured aerobically and anaerobically within a temperature range of 4-95 degree C in sediment samples consisting of either quartz-rich coarse sand or peaty clay. At temperatures above 45 degree C organic carbon compounds, including fulvic acids, were mobilized from both sediments resulting in an increased chemical oxygen demand of the water phase. Complexation of calcium and magnesium by fulvic acids resulted in the supersaturation of the water phase with regard to calcite and dolomite and thus prevented the precipitation of these carbonates. The highest rates of CO sub(2) release were observed during the first 4 days. Aerobically, the maximum velocity for CO sub(2) formation varied between 35 and 800 (sand) or 15 and 150 (peaty clay) mu mol CO sub(2) per gram volatile solids per day. Anaerobically, similar rates were observed, namely 25-500 (sand) and 10-110 (peaty clay) mu mol CO sub(2) per gram volatile solids. At temperatures above 55 degree C, CO sub(2) was produced purely chemically.
AN: 2564129
1132 of 1521
TI: Measurement of benthic nutrient fluxes in Mediterranean shellfish farms: A methodological approach.
AU: Grenz,-C.; Plante-Cuny,-M.-R.; Plante,-R.; Alliot,-E.; Baudinet,-D.; Berland,-B.
AF: Cent. Oceanol. Marseille, Stn. Mar. Endoume, rue de la Batterie des Lions, 13007 Marseille Cedex, France
SO: OCEANOL.-ACTA. 1991. vol. 14, no. 2, pp. 195-201
LA: French
ER: M (Marine)
AB: Benthic chambers were used to investigate fluctuations in nutrient fluxes and oxygen changes when comparing 2 benthic biota. Muddy sediments located under mussel-cultivation ropes were compared with a station outside the mussels' influence. Biodeposition from the mussels results in a drastic increase in the nutrient fluxes. A standard procedure is established in order to give reliable comparisons between stations and seasons: as a rule it should include six-hour periods of incubation with sampling intervals of two hours and at least 4 benthic chambers - preferably six - at each station.
AN: 2559440
1133 of 1521
TI: Sediment interactions with submersed macrophyte growth and community dynamics.
AU: Barko,-J.W.; Gunnison,-D.; Carpenter,-S.R.
AF: Environ. Lab., Waterw. Exp. Stn., Vicksburg, MS 39180-6199, USA
SO: AQUAT.-BOT. 1991. vol. 41, no. 1-3, pp. 41-65
NT: Special issue: Ecology of submersed aquatic macrophytes.
LA: English
ER: F (Freshwater)
AB: The authors review and synthesize information available in the literature on sediment interactions with submersed macrophyte growth and community dynamics. Sources of particular nutrients for uptake by submersed macrophytes are critically evaluated. Sediment physical and chemical properties are considered as a product of macrophyte growth as well as potential delimiters of growth. Aspects of macrophyte nutrition that influence littoral nutrient dynamics and macrophyte community composition are highlighted, with attention to factors affecting sediment nutrient availability. Interactive effects of sediment nutrient depletion, sedimentation, bioturbation, and microbial activity on macrophyte growth are emphasized. Major linkages and feedbacks between aquatic macrophytes and sediment properties are considered in terms of elemental exchanges and responses at the ecosystem level. Changes in macrophyte community composition during lake aging, or over relatively shorter time periods, are suggested to occur partially in response to altered sediment properties.
AN: 2559269
1134 of 1521
TI: Galerucella nymphaeae (Col., Chrysomelidae) grazing increases Nuphar leaf production and affects carbon and nitrogen dynamics in ponds.
AU: Setaelae,-H.; Maekelae,-I.
AF: Univ. Jyvaeskylae, Dep. Biol., SF-40100, Jyvaeskylae, Finland
SO: OECOLOGIA. 1991. vol. 86, no. 2, pp. 170-176
LA: English
ER: F (Freshwater)
AB: The grazing effects of the waterlily beetle Galerucella nymphaeae on Nuphar lutea stands were studied in 3 ponds in central Finland. Production of floating leaves of N. lutea and growth in the G. nymphaeae population were investigated in the ponds and bioenergetics of the beetle larvae in the laboratory. Combination of field and laboratory data enabled estimation of the effect of the beetle on the production of floating leaves of N. lutea and the consequences of grazing for the input of detritus from Nuphar into the ponds. Adults and larvae of G. nymphaeae consumed 3.0-6.1% of the net annual floating leaf production during the growing period. In addition to consumption losses, feeding accelerated the degradation rate of the leaves. This was associated with an increased flow of detrital material of Nuphar origin, and also with increased production of floating leaves in the ponds.
AN: 2553483
1135 of 1521
TI: Annual material processing by a salt marsh-estuarine basin in South Carolina, USA.
AU: Dame,-R.F.; Spurrier,-J.D.; Williiams,-T.M.; Kjerfve,-B.; Zingmark,-R.G.; Wolaver,-T.G.; Chrzanowski,-T.H.; McKellar,-H.N.; Vernberg,-F.J.
AF: Dep. Mar. Sci., Coast. Carolina Coll., Conway, SC 29526, USA
SO: MAR.-ECOL.-PROG.-SER. 1991. vol. 72, no. 1-2, pp. 153-166
NT: Bibliogr.: 71 ref.
LA: English
ER: M (Marine)
AB: A synthesis of a comprehensive annual study of material processing in the Bly Creek marsh-estuarine basin is described. The project design provides statistical estimates of material fluxes for the water column, salt marsh, and oyster reef subsystems. Material processing by the Bly Creek marsh-estuarine basin is constituent- and subsystem-specific. Inflows of material via rain, streamwater, and groundwater are small and relatively unimportant compared to tidal fluxes. The salt marsh dominates the basin in aerial extent and in terms of net material fluxes. Most constituents exhibit significant net annual import to the salt marsh. Only DON is exported from the marsh and from the basin at significant levels. The salt marsh appears to recycle most of the nitrogen and phosphorus needed for marsh grass primary production. Sufficient inorganic particulate material is imported to allow the salt marsh to maintain its elevation with respect to ongoing sea-level rise.
AN: 2551723
1136 of 1521
TI: Nutrients and chlorophyll at the interface of a watershed and an estuary.
AU: Jordan,-T.E.; Correll,-D.L.; Miklas,-J.; Weller,-D.E.
AF: Smithsonian Environ. Res. Cent., P.O. Box 28, Edgewater, MD 21037-0028, USA
SO: LIMNOL.-OCEANOGR. 1991. vol. 36, no. 2, pp. 251-267
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The authors investigated the fates of nutrients entering the Rhode River estuary from its watershed and from atmospheric deposition. Production or consumption of materials in the upper estuary was calculated from a mixing model with chloride as a conservative tracer. The upper estuary produced chlorophyll and dissolved PO sub(4) super(3) super(-) (DPO sub(4) super(3) super(-)) but consumed particulate PO sub(4) super(3) super(-) (PPO sub(4) super(3) super(-)), total inorganic N, dissolved organic N, and particulate organic C. These net fluxes were influenced more by shallow, open-water areas than by the tidal marshes which cover two-thirds of the area of the upper estuary. Ratios of chlorophyll to organic C, N, and P suggest that most of the suspended particulate organic matter in the upper estuary was produced by phytoplankton rather than derived from watershed inputs. The consumption of nitrate due to phytoplankton production and the production of DPO sub(4) super(3) super(-) due to release from particulate P after deposition in sediments resulted in low inorganic N:P ratios, contrasting sharply with the lower estuary and adjacent Chesapeake Bay.
AN: 2551032
1137 of 1521
TI: Study of carbon dioxide (CO sub(2)) problems through marine science.
AU: Honda,-M.
AF: Mar. Res. and Dev. Dep., JAMSTEC, 2-15 Natsushima-cho, Yokosuka 237, Japan
SO: REP.-JAPAN-MAR.-SCI.-TECHNOL.-CENT. 1990. no. 24, pp. 189-222
LA: Japanese
ER: M (Marine)
AB: In order to grasp the trend of carbon dioxide (CO sub(2)) increase, which causes worldwide climatic changes, and to predict the global environment in the future, it is important to understand the carbon budget and carbon cycle on the earth exactly. As the ocean is 300 times in mass and 1100 times in thermal capacity bigger than the atmosphere, it is necessary to understand the process of the carbon cycle in the ocean and to know how the ocean reacts to the CO sub(2) increase in the atmosphere. For this purpose, the study of CO sub(2) exchange through the sea surface and interaction between atmosphere, ocean, and biomass must be done accurately. Especially it is needed to carry out the observations under special conditions, when it is very difficult to do with using ordinary research vessels, in the characteristic area (arctic zone, equatorial zone, or coastal zone etc.). Coral reef is one of these characteristic areas, because the production is so high and CO sub(2) is removed through the calcification process by coral. This reviews papers discussing the carbon cycle in the ocean and considers the ability of fixing CO sub(2) by coral reef.
AN: 2546404
1138 of 1521
TI: Burrowing beetles of the genus Bledius (Staphylinidae) as agents of bioturbation in the emergent areas and shores of an athalassic inland lake (Fuente de Piedra, south of Spain).
AU: Garcia,-C.M.; Niell,-F.X.
AF: Dep. Ecol., Fac. Cienc., Campus Univ. Teatinos, 29071-Malaga, Spain
SO: HYDROBIOLOGIA. 1991. vol. 215, no. 2, pp. 163-173
LA: English
ER: B (Brackish)
AB: Bledius (Elbidus) bicornis and B. (Eucerotobledius) furcatus (Coleoptera: Staphylinidae) are the most important burrowing species in the emergent areas and shores in the athalassic lake of Fuente de Piedra (Malaga, S. of Spain). A first estimate of the importance of these organisms in this system is presented. These insects kick out sediment during their burrowing activity, which accumulates on the surface near the burrows as tumuli which can be easily eroded. The lake perimeter (17 km) is densely colonized (usual densities from 1700 to 2500 ind/m super(2)). The amount of granulated material that can be potentially kicked out was 46.22 g dry wt/m super(2)/day. At the same time, the material that constitutes the tumuli shows different characteristics from the compact ground below the surface. Thus, it is relatively enriched with organic matter (6.15 g per square meter), soluble phosphate (406.5 mu g/m super(2)) and ammonium (4856 mu g/m super(2)), whereas it lacks nitrate.
AN: 2546105
1139 of 1521
TI: Algal control of elemental sedimentary fluxes in Lake Constance.
AU: Stabel,-H.-H.
AF: Limnol. Inst., Univ. Konstanz, Mainaustr. 212, D-7750 Konstanz, FRG
CO: 23. Congress in New Zealand, (Hamilton (New Zealand)), 8 Feb 1987
SO: CONGRESS-IN-NEW-ZEALAND-1987.-PROCEEDINGS. Sladecek,-V.-ed. 1988. vol. 23, no. 2 pp. 700-706
ST: VERH.-INT.-VER.-THEOR.-ANGEW.-LIMNOL.-PROC.-INT.-ASSOC.-THEOR.-APPL.-LIMNOL.-TRAV.-ASSOC.-INT.-LIMNOL.-THEOR.-APPL. vol. 23, no. 2
LA: English
ER: F (Freshwater)
AB: It was the aim of this investigation to relate the main settling phases of predominant elements to the seasonality in the development of specific phytoplankton species. In Lake Constance the settling material is dominated by calcium carbonate, followed in order of significance by diatomaceous silica and organic matter (i.e. algae and organic debris). The seasonal fluctuations in the sedimentation rates of organic carbon were not related to seasonal changes in the phytoplankton primary productivity.
AN: 2546054
1140 of 1521
TI: Chemical characterization of polysaccharide from the slime layer of the cyanobacterium Microcystis flos-aquae C3-40.
AU: Plude,-J.L.; Parker,-D.L.; Schommer,-O.J.; Timmerman,-R.J.; Hagstrom,-S.A.; Joers,-J.M.; Hnasko,-R.
AF: Dep. Biol., Univ. Wisconsin, Oshkosh, WI 54901, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1991. vol. 57, no. 6, pp. 1696-1700
LA: English
ER: F (Freshwater)
AB: Macromolecular material from the slime layer of the cyanobacterium Microcystis flos-aquae C3-40 was defined as material that adhered to cells during centrifugation in growth medium but was dislodged by washing with deionized water and retained within dialysis tubing with a molecular-weight cutoff of 3,500. At each step of this isolation procedure, the slime was observed microscopically. Cells in the centrifugal pellet were surrounded by large amounts of slime that excluded negative stain, whereas cells that had been washed with water lacked visible slime. Two independently isolated lots of slime contained no detectable protein (< 1%, wt/wt) and consisted predominantly of anthrone-reacting polysaccharide. Sugars in a hydrolysate of slime polysaccharide were derivatized with trimethylsilylimidazole and examined by gas chromatography-mass spectrometry. The composition of the slime polysaccharide was 1.5% (wt/wt) galactose, 2.0% glucose, 3.0% xylose, 5.0% mannose, 5.5% rhamnose, and 83% galacturonic acid.
AN: 2546013
1141 of 1521
TI: Size-fractionated uptake and regeneration of ammonium and phosphate in a tropical lake.
AU: Fisher,-T.R.; Doyle,-R.D.; Peele,-E.R.
AF: Horn Point Lab., Univ. Maryland, CEES, Cambridge, MD 21613, USA
CO: 23. Congress in New Zealand, (Hamilton (New Zealand)), 8 Feb 1987
SO: CONGRESS-IN-NEW-ZEALAND-1987.-PROCEEDINGS. Sladecek,-V.-ed. 1988. vol. 23, no. 2 pp. 637-641
ST: VERH.-INT.-VER.-THEOR.-ANGEW.-LIMNOL.-PROC.-INT.-ASSOC.-THEOR.-APPL.-LIMNOL.-TRAV.-ASSOC.-INT.-LIMNOL.-THEOR.-APPL. vol. 23, no. 2
LA: English
ER: F (Freshwater)
AB: The activity of planktonic size fractions in a tropical lake near the Amazon River were examined as part of a general investigation of the biogeochemistry of floodplains. Size fractioning of the plankton was used to attempt to separate different groups of organisms and to measure the rates of N and P cycling within each size fraction. Particularly in focus was the role of bacterioplankton in the uptake and regeneration of N and P. The data indicated that a large fraction of N and P cycling in Lake Calado occurs in the < 3 mu m, largely heterotrophic, size fraction of the plankton. Greater than 1/2 of the P uptake and 10-50% of the ammonium uptake appears to be due to heterotrophic bacteria-sized organisms, and approximately equals 1/2 of the ammonium regeneration appears to occur in the same fraction, probably by different organisms of approximately the same size.
AN: 2545894
1142 of 1521
TI: How plankton change the climate (JGOFS).
AU: Williamson,-P.; Gribbin,-J.
AF: Plymouth Mar. Lab., Citadel Hill, Plymouth PL1 2PB, UK
SO: NEW-SCI. 1991. vol. 129, no. 1760, pp. 48-52
LA: English
ER: M (Marine)
AB: The oceans store about 50 times more carbon than the air, and, each year, oceans and atmosphere exchange around 15 times as much carbon dioxide as human activities produce. To predict how carbon dioxide will build up in future, and, in turn, understand changes in the climate, we need to understand how the ocean carbon cycle works. This is the aim of the Joint Global Ocean Flux Study (JGOFS), a 10-year programme that forms the main project in the International Geosphere Biosphere Programme, which investigates environmental change on a world scale. JGOFS oceanographers, biologists and chemists investigated the North Atlantic in 1989 to find out more about how and why plankton grow, what then happens to the carbon that they fix in their tissue, and what effect these organisms have on the exchange of carbon dioxide between air and sea. One target was to find out exactly what happens in the spring, when vast numbers of phytoplankton "bloom" across the oceans over a few weeks. Researchers were particularly interested in measuring the partial pressure of carbon dioxide at the surface of the sea.
AN: 2544964
1143 of 1521
TI: Role of bacteria in the North Sea ecosystem.
AU: Billen,-G.; Joiris,-C.; Meyer-Reil,-L.; Lindeboom,-H.
AF: Univ. Brussels, Campus La Plaine, CP 221, 1050 Brussels, Belgium
CO: Int. Symp. on the Ecology of the North Sea, (Netherlands), 18-22 May 1988
SO: NETH.-J.-SEA-RES. 1990. vol. 26, no. 2-4, pp. 265-293
LA: English
ER: M (Marine)
AB: For about 15 years methods available to assess the role of bacteria in organic matter cycling of aquatic ecosystems have been considerably improved. Their application to the North Sea deeply modified the vision of the ecological structure of this ecosystem which prevailed in the early seventies, as summarized e.g. by Steele (1974). A critical examination of the methodology utilized for measuring standing stock and activities of bacteria in the water column and the sediments of the North Sea is presented and the results of these measurements summarized.
AN: 2542454
1144 of 1521
TI: Biogeochemical processes governing exposure and uptake of organic pollutant compounds in aquatic organisms.
AU: Farrington,-J.W.
AF: Environ. Sci. Program, Univ. Massachusetts, Harbor Campus, Boston, MA 02125, USA
CO: Symp. on Chemically Contaminated Aquatic Food Resources and Human Cancer Risk, Research Triangle Park, NC (USA), 29-30 Sep 1988
SO: ENVIRON.-HEALTH-PERSPECT. 1991. vol. 90, pp. 75-84
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: This paper reviews current knowledge of biogeochemical cycles of pollutant organic chemicals in aquatic ecosystems with a focus on coastal ecosystems. There is a bias toward discussing chemical and geochemical aspects of biogeochemical cycles and an emphasis on hydrophobic organic compounds such as polynuclear aromatic hydrocarbons, polychlorinated biphenyls, and chlorinated organic compounds used as pesticides. The complexity of mixtures of pollutant organic compounds, their various modes of entering ecosystems, and their physical chemical forms are discussed. Important factors that influence bioavailability and disposition (e.g., organism-water partitioning, uptake via food, food web transfer) are reviewed. These factors include solubilities of chemicals; partitioning of chemicals between solid surfaces, colloids, and soluble phases; variables rates of sorption, desorption; and physiological status of organism. It appears that more emphasis on considering food as a source of uptake and bioaccumulation is important in benthic and epibenthic ecosystems when sediment-associated pollutants are a significant source of input to an aquatic ecosystem. Progress with mathematical models for exposure and uptake of contaminant chemicals is discussed briefly.
AN: 2542415
1145 of 1521
TI: Selectivity in metal uptake by stationary phase microbial populations.
AU: Premuzic,-E.T.; Lin,-Mow; Zhu,-Hong-Li; Gremme,-A.M.
AF: Dep. Appl. Sci., Brookhaven Natl. Lab., Upton, NY 11973, USA
SO: ARCH.-ENVIRON.-CONTAM.-TOXICOL. 1991. vol. 20, no. 2, pp. 234-240
LA: English
ER: F (Freshwater)
AB: In the interaction of metals with the cellular biomass of microorganisms in aqueous solutions, cell wall constituents have been implicated as being responsible for metal binding. Chemical and structural characteristics of cell membranes vary with species and should therefore influence the selective capacity for uptake of different metals by different microorganisms, and thus also influence the behavior of metallic species in the environment. While the rates of uptake of metals by microorganisms have been studied extensively, the comparative capacity for selective uptake of metals by different species of microorganisms under identical experimental conditions has not been studied systematically. To test for this property, cellular biomass derived from eight representative microorganisms has been allowed to interact under similar experimental conditions with acidic solutions of seven heavy metals. The results of these studies show that, in addition to metal selectivity, there is also a species dependent differentiation in the uptake capacity.
AN: 2541985
1146 of 1521
TI: Top predators in the Southern Ocean: A major leak in the biological carbon pump.
AU: Huntley,-M.E.; Lopez,-M.D.G.; Karl,-D.M.
AF: Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093, USA
SO: SCIENCE-WASH.. 1991. vol. 253, no. 5015, pp. 64-66
LA: English
ER: M (Marine)
AB: Primary productivity in the Southern Ocean is approximately 3.5 gigatons of carbon per year, which accounts for nearly 15 percent of the global total. The presence of high concentrations of nitrate in Antarctic waters suggests that it might be possible to increase primary production significantly and thereby alleviate the net accumulation of atmospheric carbon dioxide. An analysis of the food web for these waters implies that the Southern Ocean may be remarkably inefficient as a carbon sink. This inefficiency is caused by the large flux of carbon respired to the atmosphere by air-breathing birds and mammals, dominant predators in the unusually simple food web of Antarctic waters. These top predators may transfer into the atmosphere as much as 20 to 25 percent of photosynthetically fixed carbon.
AN: 2541843
1147 of 1521
TI: Distribution of dissolved iron in sediment pore waters at submillimetre resolution.
AU: Davison,-W.; Grime,-G.W.; Morgan,-J.A.W.; Clarke,-K.
AF: Inst. Environ. and Biol. Sci., Univ. Lancaster, Lancaster LA1 4YQ, UK
SO: NATURE. 1991. vol. 352, no. 6333, pp. 323-325
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Much effort has been directed at measuring concentration gradients at the sediment/water interface of aquatic systems, where the biogeochemical cycling of natural and pollutant species is particularly active. Precise measurements of oxygen gradients using microelectrodes and estimates from independently determined fluxes suggest that concentration gradients in this region often extend only to depths of similar to 1 mm, much less than the resolution ( similar to 1 centimetre) of conventional techniques. We have developed a new method for measuring pore-water composition in which diffusive equilibrium is established rapidly (within minutes) in a thin film of gel inserted in the sediment. On removal, the dissolved components are fixed, allowing chemical measurements to be made at high spatial resolution (<1 mm) on a stable solid phase. Using MeV-proton-induced X-ray emission (PIXE) to analyse the dried gel, we have measured iron concentrations in lacustrine pore waters at submillimeter resolution, revealing steep concentration gradients and sub-surface maxima consistent with a hypothesis of localized, reductive dissolution of fresh material.
AN: 2540026
1148 of 1521
TI: Methylated sulfur compounds in microbial mats: In situ concentrations and metabolism by a colorless sulfur bacterium.
AU: Visscher,-P.T.; Quist,-P.; van-Gemerden,-H.
AF: Dep. Microbiol., Univ. Groningen, Kerklaan 30, 9751 NN Haren, Netherlands
SO: APPL.-ENVIRON.-MICROBIOL. 1991. vol. 57, no. 6, pp. 1758-1763
LA: English
ER: M (Marine)
AB: The concentrations of the volatile organic sulfur compounds methanethiol, dimethyl disulfide, and dimethyl sulfide (DMS) and the viable population capable of DMS utilization in laminated microbial ecosystems were evaluated. Significant levels of DMS and dimethyl disulfide (maximum concentrations of 220 and 24 nmol cm super(3)/sediment, respectively) could be detected only at the top 20 mm of the microbial mat, whereas methanethiol was found only at depth horizons from 20 to 50 mm (maximum concentration of 42 nmol cm super(3)/sediment). DMS concentrations in the surface layer doubled after cold hydrolysis of its precursor, dimethyl-sulfoniopropionate. Most-probable-number counts revealed 2.2 x 10 super(5) cells cm super(3)/sediment, in the 0- to 5-mm depth horizon, capable of growth on DMS as the sole source of energy. An obligately chemolithoautotrophic bacillus designated strain T5 was isolated from the top layer of the marine sediment. Continuous culture studies in which DMS was the growth-limiting substrate revealed a maximum specific growth rate of 0.10/h and a saturation constant of 90 mu mol/l for aerobic growth on this substrate.
AN: 2537720
1149 of 1521
TI: Lead removal from contaminated water by a mixed microbial ecosystem.
AU: Bender,-J.A.; Archibold,-E.R.; Ibeanusi,-V.; Gould,-J.P.
AF: Dep. Biol., Morehouse Coll., Atlanta, GA 30314, USA
CA: International Assoc. on Water Pollution Research and Control, London (UK)
CO: 14. Bienn. Conf. of the IAWPRC: Water Pollution Research and Control, Brighton (UK), 18-21 Jul 1988
SO: WATER-POLLUTION-RESEARCH-AND-CONTROL,-BRIGHTON,-PART-5. Lijklema,-L.;et-al.-eds. 1989. vol. 21, no. 12 pp. 1661-1664
ST: WATER-SCI.-TECHNOL. vol. 21, no. 12
LA: English
ER: F (Freshwater)
AB: This study explored the advantages of using an integrated ecosystem for the uptake of lead and examined some of the possible mechanisms for the transfer of the metal through the system with eventual binding in the microbial biomass. Strategies were applied to (1) stimulate enhanced production of biomass and consequent lead recovery by simple enrichments of the microbial environment, and (2) increase the microbial tolerance and lead uptake capacity by adaptation of the component species. The microbial ecosystem employed was one which arose spontaneously after pond enrichment with silaged grass clippings and moved through a predictable microbial succession. Ecosystem processes and microbial relationships resulted in the mobilization of metal in the soil bed and water column with ultimate deposition in the surface biomass. The stable silage-microbe biomass, floating at the top of the pond, bound the metal for extended periods of time.
AN: 2535280
1150 of 1521
TI: Depletion of barium and radium-226 in Black Sea surface waters over the past thirty years.
AU: Falkner,-K.K.; O'-Neill,-D.J.; Todd,-J.F.; Moore,-W.S.; Edmond,-J.M.
AF: Groupe Rech. Geod. Spat., Cent. Natl. Etud. Spat., 18 Ave. Edouard Belin, 31055 Toulouse Cedex, France
SO: NATURE. 1991. vol. 350, no. 6318, pp. 491-494
LA: English
ER: M (Marine)
AB: The nearly landlocked waters of the Black Sea support a valuable fishery, but are also particularly vulnerable to anthropogenic disturbance. Here we use dissolved barium and radium-226 as tracers, to investigate the biogeochemical health of the sea. Both elements are brought to surface waters by vertical mixing of deeper, enriched waters, and by rivers; these inputs should ordinarily be balanced by outflow of surface waters at the Bosphorus, and by biologically mediated removal of super(226)Ra-bearing barite. We show, however, that surface-water inventories have been substantially depleted over the past few decades. Observations suggest that steady-state cycling of these elements has been perturbed by increased primary productivity, presumably fuelled by nutrients from industry and agricultural runoff, and to a lesser extent by decreased fluvial sediment loads owing to extensive impoundment of rivers in the region.
AN: 2535226
1151 of 1521
TI: The mechanism controlling plant nutrient concentrations in the northern Adriatic Sea.
AU: Gilmartin,-M.; Degobbis,-D.; Revelante,-N.; Smodlaka,-N.
AF: Dep. Zool., Univ. Maine, Orono, ME 04469, USA
SO: INT.-REV.-GESAMT.-HYDROBIOL. 1990. vol. 75, no. 4, pp. 425-445
NT: Bibliogr.: 77 ref.
LA: English
ER: M (Marine)
AB: A 20 year data set for the northern Adriatic was analyzed and the factors establishing the nutrient environment identified. Concentrations ranged widely (TIN 0.0-78, PO sub(2) 0.01-1.1, and SiO sub(4) 0.0-59 mmol/m super(3)). In early winter remineralization increased concentrations. Characteristic winter, late spring and fall phytoplankton blooms alternately decreased and increased concentrations, as modified by river input. In summer nutrients were minimal under a semi-closed circulation pattern and high vertical stability, due to closely coupled nitrogen and phosphorus assimilation-regeneration processes and biogenic silica sedimentation. "New" primary production supported mainly by river input of "new" nutrients approximated "regenerated" primary production supported by regenerated nutrients, making the ecosystem especially sensitive to eutrophication pressure from anthropogenic increases in the Po River nutrient load.
AN: 2534558
1152 of 1521
TI: Anaerobic microbial biogeochemistry in sediments from two basins in the Gulf of Maine: Evidence for iron and manganese reduction.
AU: Hines,-M.E.; Bazylinski,-D.A.; Tugel,-J.B.; Lyons,-W.B.
AF: Inst. Stud. Earth, Oceans and Space, Univ. New Hampshire, Durham, NH 03824, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1991. vol. 32, no. 4, pp. 313-324
LA: English
ER: M (Marine)
AB: Rates of sulphate reduction, denitrification and glucose turnover were determined in surface sediments collected from Jeffreys and Wilkinson Basins in the Gulf of Maine. These data were compared to porewater profiles of iron and manganese. Three distinct anaerobic biogeochemical situations were evident: sulphate reduction was dominant and active near the sediment-water interface (deeper portions of Jeffreys Basin); denitrification was active in the upper few centimetres and was underlain by rapid sulphate reduction (slope of Jeffreys Basin); denitrification was dominant (Wilkinson Basin). An apparent iron and manganese reduction region was evident in all cores. Since glucose turnover was active and both denitrification and sulphate reduction were low within this metal reduction zone it is possible that microbial metal reduction is a significant process within the basin sediments.
AN: 2532355
1153 of 1521
TI: Pressure tolerance of oceanic flagellates: Implications for remineralization of organic matter.
AU: Turley,-C.M.; Carstens,-M.
AF: Plymouth Mar. Lab., Citadel Hill, Plymouth PL1 2PB, UK
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1991. vol. 38, no. 4A, pp. 403-413
LA: English
ER: M (Marine)
AB: Active growth of the total mixed flagellate population, comprising three species isolated from the euphotic zone in the northeast Atlantic, occurred up to pressures of 200 atm. (equivalent to 2000 m water depth). At pressures greater than 200 atm. there was a steady decrease in total flagellate numbers. These results could be misinterpreted to conclude that pressures greater than 200 atm. have a deleterious effect on flagellates. When the effects of pressure were investigated at the species level a different picture emerges. One species, Paraphysomonas butcheri , was weakly barotolerant reproducing at up to 100 atm. Another, Bodo curvifilus , had a wide barotolerance dividing at up to pressures of 300 atm., while the third, a Cercomonas -like species, only grew at pressures of 300 atm. and over. Such results indicate the importance of investigations at the species level as well as population level.
AN: 2531044
1154 of 1521
TI: Ice-core record of oceanic emissions of dimethylsulphide during the last climate cycle.
AU: Legrand,-M.; Feniet-Saigne,-C.; Saltzman,-E.S.; Germain,-C.; Barkov,-N.I.; Petrov,-V.N.
AF: Lab. Glaciol. et Geophys. Environ., B.P. 96, 38402 St. Martin d'Heres, Cedex, France
SO: NATURE. 1991. vol. 350, no. 6314, pp. 144-146
LA: English
ER: M (Marine)
AB: The Vostok ice core in Antarctica has provided one of the longest climate records, enabling the stable-isotope, major-ion and gas composition of the atmosphere to be reconstructed over many thousands of years. Depth profiles along this core of methanesulphonate and non-seasalt sulphate (produced by the atmospheric oxidation of dimethylsulphide), provide the first historical record of biogenic sulphur emissions from the Southern Hemisphere oceans over a complete glacial-interglacial cycle (160 kyr), and indicate increased oceanic emissions of dimethylsulphide during the later stages of the glacial period, compared with the present day. The observed glacial-interglacial variations in methanesulphonate and non-seasalt sulphate confirm that the ocean-atmosphere sulphur cycle is extremely sensitive to climate change.
AN: 2528220
1155 of 1521
TI: Particle (plankton) size structure across the Azores Front (Joint Global Ocean Flux Study North Atlantic bloom experiment).
AU: Kahru,-M.; Nommann,-S.; Zeitzschel,-B.
AF: Inst. Ecol. and Mar. Res., Tallinn, Estonia
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1991. vol. 96, no. C4, pp. 7083-7088
LA: English
ER: M (Marine)
AB: The horizontal distributions of particle size spectrum and chlorophyll a concentration across the northern edge of the North Atlantic Subtropical Gyre along 21 degree W were studied as part of the Joint Global Ocean Flux Study North Atlantic Bloom Experiment in March-April, 1989. An abrupt change in the particle size spectrum at 32 degree 40'N was located within the broad thermohaline front between the central gyre water in the south and the Azores Current in the north. Whereas the small particulate fraction (1-10 mu m) and chlorophyll a concentration were similar (within a factor of 2), the abundance of the "diatom" size fraction (28-72 mu m) showed a drastic increase by more than an order of magnitude in the Azores Current. The diatom fraction seemed to contribute little to the chlorophyll pool, indicating a postbloom condition.
AN: 2528121
1156 of 1521
TI: Sulfate reduction in marine sediments from the Baltic Sea-North Sea transition.
AU: Joergensen,-B.B.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark
SO: OPHELIA. 1989. vol. 31, no. 1, pp. 1-15
LA: English
ER: M (Marine)
AB: The spatial distribution and intensity of sulfate reduction was studied in the upper 0-15 cm of coastal sediments by radiotracer technique. The study area extended from the eastern North Sea through Skagerrak and Kattegat into the Belt Sea at the entrance to the Baltic Sea. The 27 sampling stations ranged from pure sand to clayey mud with organic contents from 0.2 to 13% dry weight. Water depths ranged from 7 to 200 m. Depth-integrated sulfate reduction rates were mostly 1-5 mmol/m super(2)/d in the Skagerrak-Kattegat-Belt Sea area. Lowest rates, 0.08-1.0 mmol/m super(2)/d, were encountered in low-organic sands from exposed parts of the North Sea. Extremely high rates, 17-30 mmol/m super(2)/d, were found in the Helgoland Bight, SE North Sea, near the mouth of the Elbe River. Intensive sulfate reduction was associated with areas of fine-grained sediment and with high deposition rates of organic detritus. The degree of pyritization correlated positively to sulfate reduction rates (r = 0.63) and to FeS concentrations (r = 0.70). In deeper stations of northern Kattegat and Skagerrak, < 5% of the iron occurred as pyrite.
AN: 2527794
1157 of 1521
TI: Oxygen uptake, bacterial distribution, and carbon-nitrogen-sulfur cycling in sediments from the Baltic Sea-North Sea transition.
AU: Joergensen,-B.B.; Revsbech,-N.P.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark
SO: OPHELIA. 1989. vol. 31, no. 1, pp. 29-49
LA: English
ER: M (Marine)
AB: Chemical zonations and bacterial distribution and metabolism were studied at fourteen sediment stations in the Belt Sea, the Kattegat, and the Skagerrak. Water depths were 14-200 m and sediment types ranged from clay and silt to fine sand. The oxic zone as determined by microelectrodes was only 1.3-5.6 mm deep while the oxidized zone (Eh > + 100 mV) was one to several cm. Roughly 90% of the oxidized layer was thus anoxic. A pH minimum occurred just below the oxic-anoxic interface. Subsurface nitrate maxima extended to depths of 1.5-5 cm. Total bacterial densities at the sediment surface were 0.25-10.0 x 10 super(8)/cm super(3). Bacterial distributions showed no correlation with the measured rates of aerobic or anaerobic metabolism. Acetate turnover rates highly exceeded sulfate reduction, probably due to problems of identifying the bacterially available acetate pool and its specific radioactivity. A rough carbon budget for the Belt Sea and Kattegat areas showed that 44% of the total primary production in the water column reached the sea floor by sedimentation.
AN: 2527386
1158 of 1521
TI: Formation of methylmercaptan and dimethylsulfide from methoxylated aromatic compounds in anoxic marine and fresh water sediments.
AU: Finster,-K.; King,-G.M.; Bak,-F.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark
SO: FEMS-MICROBIOL.-ECOL. 1990. vol. 74, no. 4, pp. 295-302
LA: English
ER: M (Marine); F (Freshwater)
AB: Anaerobic formation of dimethylsulfide (DMS) and methylmercaptan (MSH) in anoxic sulfide-containing slurries from marine and fresh water sediments was stimulated by addition of syringate (4-hydroxy,3,5,-dimethoxybenzoate) and 3,4,5-trimethoxybenzoate. The release of DMS and MSH occurred during the consumption of the aromatic monomers and ceased after their depletion. This study demonstrates a previously unknown microbial process by which DMS and MSH are formed during anaerobic decomposition of methoxylated aromatic compounds in marine and freshwater sediments.
AN: 2520708
1159 of 1521
TI: A rate for the scavenging of fine particles by macroaggregates in a deep estuary.
AU: Lavelle,-J.W.; Cudaback,-C.N.; Paulson,-A.J.; Murray,-J.W.
AF: NOAA/Pac. Mar. Environ. Lab., Seattle, WA 98195, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1991. vol. 96, no. C1, pp. 783-790
LA: English
ER: M (Marine)
AB: super(234)Th activity profiles in Puget Sound have been studied using a model that incorporates reversible exchanges between dissolved, fine particulate, and macroaggregate Th reservoirs. Macroaggregate settling is made responsible for the downward flux of Th and the vertical gradients of activity in measured profiles. Least squares fits of model to data yield rates/time scales for the exchange processes involved. Rates of sorption and remobilization characterizing the exchange between dissolved and fine-particulate forms of the isotope cannot be individually identified from these data, but acceptable model values include those measured in the laboratory. Rates of sorption that depend on particulate concentrations which increase to the seafloor result in profiles of dissolved Th having above-bottom maxima. Based on inferred exchange rates, the residence time for fine particles introduced at the surface of this deep ( similar to 200 m) estuary is estimated to be 11-16 days when w sub(s) = 100 m/d.
AN: 2519150
1160 of 1521
TI: Iron availability, nitrate uptake, and exportable new production in the Subarctic Pacific.
AU: Banse,-K.
AF: Sch. Oceanogr., Univ. Washington, Seattle, WA 98195, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1991. vol. 96, no. C1, pp. 741-748
LA: English
ER: M (Marine)
AB: Iron-limitation of phytoplankton was recently postulated as the reason for the high nutrient (N, P) but low phytoplankton concentrations offshore in the subarctic and equatorial Pacific, as well as the circumpolar southern ocean. This hypothesis led to the suggestion that small additions of iron to those large areas might be a way of removing significant amounts of anthropogenic CO sub(2) from the atmosphere. Rates of nitrate uptake in bioassays from the open Gulf of Alaska by Martin et al. (1989) are reinterpreted. During the exponential phase of phytoplankton growth, iron addition affected the rate of nitrate uptake significantly at only one of the 3 stations. It is suggested that in the field, grazing normally seems to prevent the phytoplankton from reaching concentrations that reduce the iron (and nitrate) to levels that depress division rates drastically. Although nitrate uptake may be equated with new production, the export to depth of new organic material (and hence of CO sub(2)) is not predictable from assays in small (liter) containers, especially so because the role of the large grazers on the size composition of the phytoplankton and the production of large sinking particle is not evaluated.
AN: 2518477
1161 of 1521
TI: Ammonium recycling versus denitrification in Chesapeake Bay sediments.
AU: Kemp,-W.M.; Sampou,-P.; Caffrey,-J.; Mayer,-M.; Henriksen,-K.; Boynton,-W.R.
AF: Horn Point Environ. Lab., Univ. Maryland, P.O. Box 775, Cambridge, MD 21613, USA
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 7, pp. 1545-1563
LA: English
ER: M (Marine); B (Brackish)
AB: Contemporaneous measurements are reported for nitrification, denitrification, and net sediment-water fluxes of NH sub(4) super(+) and NO sub(3) super(-) in the mesohaline region of Chesapeake Bay. Seasonal cycles over a 2-yr period were characterized by a midsummer maximum in NH sub(4) super(+) efflux to the overlying water and a May peak in NO sub(3) super(-) removal from water by sediments. Coherent temporal patterns for nitrification and denitrification were observed, with relatively high values in spring and fall and virtual elimination of both processes in summer. Indirect measurements indicate that nitrification was limited by the shallow O sub(2) penetration (<1 mm) here compared to reports for other marine sediments (2-6 mm). In addition, a strong positive correlation between the two processes suggested that denitrification was generally controlled by nitrification. Comparisons of NO sub(3) super(-) fluxes and net nitrification rates (nitrification minus NO sub(3) super(-) reduction to NH sub(4) super(+)) revealed that measurements of denitrification with the acetylene block method systematically underestimated actual rates.
AN: 2510639
1162 of 1521
TI: Impact of eutrophication on the silicate cycle of man-made basins in the Rhine Delta.
AU: Admiraal,-W.; van-der-Vlugt,-J.C.
AF: Natl. Inst. Public Health and Environ. Prot., P.O. Box 1, 3720 BA Bilthoven, Netherlands
SO: HYDROBIOL.-BULL. 1990. vol. 24, no. 1, pp. 23-36
NT: Special issue: Research on perturbed aquatic ecosystems.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The impact of eutrophication on the biogeochemical cycle of silicate in the Rhine Delta was analysed by 1) comparing the seasonal variation in river water, stagnant fresh water and coastal seawater and 2) observations in well-controlled experimental reservoirs subjected to different regimes of phosphate precipitation. The high input of dissolved silicate from Rhine water was rapidly depleted in receiving water systems through vigorous phytoplankton (diatom) growth. In reservoirs ca. 50% of the silicate input was retained over a seven years' observation period. Regeneration of silicate immobilized by diatoms was accelerated by very dense blooms of phytoplankton in reservoirs and in Lake IJssel that increased the pH value over 9.
AN: 2510601
1163 of 1521
TI: Stable carbon isotopes and the C:N ratio in the estuaries of the Pamlico and Neuse Rivers, North Carolina.
AU: Matson,-E.A.; Brinson,-M.M.
AF: Mar. Lab., Univ. Guam, UOG Stn., Mangilao 96923, Guam
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 6, pp. 1290-1300
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The C:N and stable C isotope ratios ( delta super(13)C) of sedimentary and seston organic C (OC) were used to identify OC sources and sites of deposition in two large estuaries in North Carolina. In the upper 10 km of the oligohaline zones, C:N ratios of sediment are characteristic of particulate terrestrial plant material (> 15). The delta super(13)C values increase linearly with distance from freshwater tributaries to the mouths of the estuaries ( similar to 20 ppt salinity), > 40 km from the ocean. Observed gradients in isotopic and C:N ratios imply that conservative mixing of freshwater and marine OC occurs. Phytoplankton in the estuaries produce at least 10 times more particulate OC than is delivered in runoff, however, and its biomass is recycled at rates much faster than those of water exchange. The observed gradients are therefore largely attributed to recycling of a resident pool of estuarine C, atmospheric CO sub(2), and an increasing marine bicarbonate fraction from the salt wedge downriver. Essentially lentic conditions in these estuaries ensure the dominance of in situ biological processes.
AN: 2510398
1164 of 1521
TI: The sulfur cycle of freshwater sediments: Role of thiosulfate.
AU: Joergensen,-B.B.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, DK-8000 Aarhus C, Denmark
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 6, pp. 1329-1342
LA: English
ER: F (Freshwater)
AB: The formation and pathways of thiosulfate (S sub(2)O sub(3) super(2-)) in anoxic sediment were studied in the Odder River and Brabrand Lake, Denmark. Time-course experiments were done in slurries with four super(35)S tracers: SO sub(4) super(2-), H sub(2)S, and S sub(2)O sub(3) super(2-) with either the inner (oxidized) or the outer (reduced) S atom labeled. The two sediments gave similar results. Of all the S sub(2)O sub(3) super(2-) consumed in Brabrand Lake sediment, 6% was oxidized, 50% was reduced, and 44% was disproportionated. S sub(2)O sub(3) super(2-) disproportionation is an inorganic fermentation in certain SO sub(4) super(2-)-reducing bacteria by which the inner and outer S atoms are simultaneously transformed into SO sub(4) super(2-) and sulfide, respectively. Altogether, 28% of the S sub(2)O sub(3) super(2-)-S was converted into SO sub(4) super(2-) and 72% was converted into sulfide. S sub(2)O sub(3) super(2-) inhibited SO sub(4) super(2-) reduction by 75%. The immediate products of anoxic sulfide oxidation were 34% SO sub(4) super(2-) and 66% S sub(2)O sub(3) super(2-). Half of the oxidized sulfide was ultimately converted into SO sub(4) super(2-) and half was recycled back to sulfide via S sub(2)O sub(3) super(2-). Two-thirds of the S in the sulfide-thiosulfate "minicycle" remained at an oxidation state of -2. S sub(2)O sub(3) super(2-) is thus a key intermediate in the S cycle, both as a main product of anoxic sulfide oxidation and as a shunt between oxidative and reductive pathways.
AN: 2510378
1165 of 1521
TI: Distribution of dissolved trace metals in western Bay of Bengal.
AU: Satyanarayana,-D.; Murty,-P.V.S.P.
AF: Andhra Univ., Sch. Chem., Visakhapatnam 503 003, India
SO: INDIAN-J.-MAR.-SCI. 1990. vol. 19, no. 3, pp. 206-211
LA: English
ER: M (Marine)
AB: Concentrations of Ni, Zn, Cd, Cu, Mn, Pb and Fe were determined in 93 water samples (17 inshore and 7 offshore stations) collected at different depths from the western Bay of Bengal in March 1988. Surface distribution showed that relatively high concentrations of trace metals and nutrients are associated with low salinities in inshore and vice versa in the offshore waters. The depth profiles on Ni, Zn and Cd with surface depletion and bottom enrichment resembled those of nutrients, indicating their involvement in biogeochemical cycles. While the profiles of Cu were indicative of its involvement in the scavenging process at intermediate depth, those of Mn and Pb with surface enrichment and bottom depletion, appeared to be controlled by river inputs and anthropogenic atmospheric flux. However, surface enrichment and bottom depletion observed in the case of Fe profiles, contrary to its normal oceanic distribution, are attributed to the precipitation and/or adsorption on suspended particles leading to its transport to the sediments. The atomic ratios of Ni, Zn and Cd with nutrients were evaluated through their regression equations and compared with those reported earlier for Pacific, Atlantic and Indian Oceans.
AN: 2509850
1166 of 1521
TI: Analytical phosphorus fractionation of sediment trap material.
AU: Liebezeit,-G.
AF: Nationalparkverwalt., Oekosystemforsch. Niedersaechs. Wattenmeer, Virchowstr. 1, W-2940 Wilhelmshaven, FRG
SO: MAR.-CHEM. 1991. vol. 33, no. 1-2, pp. 61-69
LA: English
ER: M (Marine)
AB: Sediment trap samples from the Sea of Marmara, the North Sea, the South China Sea and the Voering Plateau were analysed for water- and acid-extractable inorganic and total organic phosphorus. Whereas water-extractable P accounts for < 3.6% of total P, acid-extractable P represents up to 62%. Inorganic phosphorus may originate from biogenic carbonate and silica, detrital clay minerals, fish debris and atmospheric fallout. The relative contributions from these sources are reviewed.
AN: 2508176
1167 of 1521
TI: Trace elements in lacustrine sediments.
OT: Elementi in traccia e sedimenti lacustri
AU: Baudo,-R.; Ferrari,-A.; Pranzo,-A.
CA: Istituto Italiano di Idrobiologia, Verbania Pallanza (Italy)
SO: DIRECTOR'-S-REPORT-ON-THE-SCIENTIFIC-ACTIVITY-OF-THE-INSTITUTE-FOR-THE-YEAR-1987. RELAZIONE-DEL-DIRETTORE-SULL'-ATTIVITA-SCIENTIFICA-DELL'-INSTITUTO-NELL'-ANNO-1987. Bernardi,-R.-de-ed. 1989. no. 19 pp. 22-26
ST: DOC.-IST.-ITAL.-IDROBIOL. no. 19
LA: Italian
ER: F (Freshwater)
AB: Since 1986 sediments from several Italian lakes have been sampled with the objective of relating their chemical composition to the geochemistry of the respective drainage basins and eventually spotting possible modifications of the biogeochemical cycles due to human activities.
AN: 2505481
1168 of 1521
TI: Remobilization of Cu from marine particulate organic matter and from sewage.
AU: Paulson,-A.J.; Curl,-H.C.,Jr.; Cokelet,-E.D.
AF: Pacific Mar. Environ. Lab., NOAA, 7600 Sand Point Way NE, Seattle, WA 98115-0070, USA
SO: MAR.-CHEM. 1991. vol. 33, no. 1-2, pp. 41-60
LA: English
ER: M (Marine)
AB: The possible causes of enrichments of dissolved Cu in the bottom waters of Puget Sound were examined in a series of experiments designed to measure the release of Cu from surface marine organic suspended matter and from sewage-derived particles under ambient conditions. Decomposition of organic matter and ion-exchange controlled the release of about one-third of the Cu bound to large particles (> 53 mu m). In contrast, no Cu was released from smaller particles (< 53 mu m) suspended in natural seawater and only 5% of the Cu on small particles was released into artificial seawater with a low dissolved Cu concentration. Within 15 min of mixing primary primary effluent with natural seawater, 40% of the dissolved Cu was lost from solution by flocculation. Between 15 min and 4 days, 25% of the total effluent Cu was released back into solution. This release could have originated either from particulate Cu on the original sewage particles or from the flocculated Cu that was formed from dissolved Cu within the first 15 min.
AN: 2501133
1169 of 1521
TI: Zinc budget in the Mediterranean Sea: A hypothesis for non-steady-state behavior.
AU: Ruiz-Pino,-D.P.; Nicolas,-E.; Bethoux,-J.P.; Lambert,-C.E.
AF: Lab. Phys. et Chim. Mar., Univ. Paris 6, UA CNRS, B.P. 8, F06230 Villefranche-sur-Mer, France
SO: MAR.-CHEM. 1991. vol. 33, no. 1-2, pp. 145-169
LA: English
ER: M (Marine)
AB: The concentrations of Zn were determined in surface and deep-water samples at 11 sites in the Mediterranean Sea during the PHYCEMED 2 (Oct 1983) cruise. The Zn vertical profile is marked by a surface concentration (typically 3.0 nmol/kg in the Western Basin) higher than in the open ocean where the surface layer is Zn depleted. The subsurface layer (between 30 and 80 m) shows Zn and salinity minimun values along the path of the Atlantic inflow throughout the Western Basin. A weak intermediate maximum is present between 200- and 400-m depth, whereas Zn values are homogeneous in the deep waters from similar to 300-m depth, as are T and S values. In deep water, the Zn/P ratios are similar to those of plankton; this is a good argument for a biological Zn cycle, which may explain the intermediate maximum caused by remineralization of organic matter settling from the euphotic layer. The deep layer is expected to be homogeneous as a result of the basin dynamics, whereas the biological cycle will induce a Zn depletion in the surface layer.
AN: 2501026
1170 of 1521
TI: The role of microorganisms in sedimentation in the ocean.
OT: Rol' mikroorganismov v sedimentatsionnykh protsessakh v okeane
AU: Stupakova,-T.P.; Dubinina,-G.A.; Demina,-L.L.
AF: IOAN SSSR, Moscow, USSR
SO: MIKROBIOLOGIYA-MICROBIOLOGY. 1991. vol. 60, no. 1, pp. 148-156
LA: Russian
ER: M (Marine)
AB: A study was made of the ability of Moraxella sp. D-431 and fraction from individual cells of bacterioplankton taken from various depths in the Southwest Pacific to accumulate Cu, Ni, Co, Fe and Mn at the initial concentrations of 0.1-100 mu g/l. The accumulation rates of the metals were as follows: Cu = Co = Fe > Ni > Mn and they varied from 0.5 to 0.7 multiplied by 10 super(6) and from 2 to 3 multiplied by 10 super(7) in Moraxella) sp. and bacterioplankton respectively, which was by 2 or 3 orders higher than the respective values known for other hydrobionts. The results have shown that bacterioplankton contributes greatly towards heavy metal accumulation in suspended matter and sea water.
AN: 2499291
1171 of 1521
TI: (Accumulation of radionuclides by fish at the initial period of radioactive contamination of a river ecosystem.).
OT: Nakoplenie radionuklidov ryboj v nachal'nyj period radioaktivnogo zagryazneniya rechnoj ehkosistemy
AU: Vintsukevich,-N.V.; Tomilin,-Yu.A.
AF: Obl. Sanit. Ehpidemiol. Stn. Nikolaev, USSR
SO: EHKOLOGIYA. 1990. no. 5, pp. 35-40
LA: Russian
ER: F (Freshwater)
AB: The content of radionuclides in water components of the Dnieper River after the Chernobyl accident contamination was studied. Radionuclide composition of water, plants, bottom sediments and fish is considered. Concentration of radionuclides in various parts of body of bream, perch, pike-perch, roach, silver bream, white-eyed bream and sabrefish is tabled by individual elements. The least amount of super(90)Sr was accumulated in muscular tissue. The paper compares estimated human consumption of contaminated fish with the standards of sanitation rules for nuclear power plants in the USSR.
AN: 2499105
1172 of 1521
TI: Stable isotopic and carbonate cyclicity in Lower Cretaceous deep-sea sediments: Dominance of diagenetic effects.
AU: Thierstein,-H.R.; Roth,-P.H.
AF: Geol. Inst., ETH Cent., CH-8092 Zurich, Switzerland
SO: MAR.-GEOL. 1991. vol. 97, no. 1-2, pp. 1-34
LA: English
ER: M (Marine)
AB: Oxygen and carbon isotopic variability of dominant (< 38 mu m) carbonate fraction within bedded, organic-carbon rich Lower Cretaceous sediment intervals from various DSDP sites are closely correlated with preservational changes in the carbonates. Isotopic fluctuations are absent where carbonate contents vary little and where the carbonate fraction is dominated by biogenic phytoplankton remains. Within each of the studied intervals oxygen and carbon isotopic ratios become increasingly more negative in samples with carbonate higher than about 60% in which the proportion of diagenetic microcarbonate increases rapidly. Carbon isotopic ratios show a trend towards positive values in samples with carbonate contents of less than 40% and strong signs of dissolution. The taxonomic composition of nannofossil assemblages varies little within single intervals, despite significant differential diagenesis among individual beds; this points towards ecological stability of oceanic surface waters during the deposition of alternating beds. Bedding is, however, closely related to changing bioturbation intensity, indicating repeated fluctuations of the deep-water renewal rates and oxygen supply.
AN: 2498518
1173 of 1521
TI: RRS Discovery Cruise 191, 11 May-05 Jun 1990. Biogeochemical Ocean Flux Studies (BOFS Cruise A2).
AU: Angel,-M.V.; et-al.
AF: Inst. Oceanogr. Sci., Deacon Lab., Wormley, Godalming, Surrey GU8 5UB, UK
SO: CRUISE-REP.-INST.-OCEANOGR.-SCI.-DEACON-LAB. 1991. no. 222, 78 pp
LA: English
ER: M (Marine)
AB: This report describes the scientific activities carried out on Discovery Cruise 191, the second in a series of three cruises on Discovery run under the aegis of the Biogeochemical Ocean Flux Study (BOFS). The aim of these three cruises and two simultaneous cruises on Charles Darwin was to conduct the Lagrangian experiment during the 1990 spring bloom, and to follow the fate of carbon fixed by photosynthesis.
AN: 2494743
1174 of 1521
TI: A statistical analysis of the contribution of structural groups of plankton to inorganic carbon fixation.
OT: Funktsional'naya rol' strukturnykh grupp planktona v fiksatsii neorganicheskogo ugleroda. Statisticheskij podkhod
AU: Smirnov,-N.A.; Demchev,-V.V.; Fedorov,-V.D.
AF: Gos. Univ., Moscow, USSR
SO: BIOL.-NAUKI. 1991. no. 3, pp. 141-159
LA: Russian
ER: M (Marine)
AB: Individual contribution was estimated of nannomicro-picophyto- and bacterioplankton to the total fixation of C in CO sub(2) at the expense of photosynthesis and dark assimilation (nannomicro- and picoplankton) and chemosynthesis and heterotrophic assimilation (bacterioplankton). Factorial experiment was made using a combination of methods of fractional filtration and selective biochemical inhibition. A general model of selective inhibition is presented. A statistical approach was developed to estimate the model parameters which imply intensive super(14)C fixation by functional groups. The method was successfully applied to estimates of phyto- and bacterioplankton production in the White Sea estuaries.
AN: 2491286
1175 of 1521
TI: The organosulphur cycle: Aerobic and anaerobic processes leading to turnover of C sub(1)-sulphur compounds.
AU: Kelly,-D.P.; Baker,-S.C.
AF: Higher Educ. Aff., Nat. Environ. Res. Counc., Polaris House, North Star Ave., Swindon SN2 1EU, UK
CO: 6. Int. Symp. on Microbial Growth on C sub(1)-Compounds, Goettingen (FRG), 20-25 Aug 1989
SO: MICROBIAL-GROWTH-ON-C-sub1-COMPOUNDS. Andreesen,-J.R.;Bowien,-B.-eds. 1990. vol. 87, no. 3-4 pp. 241-246
ST: FEMS-MICROBIOL.-REV. vol. 87, no. 3-4
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: The processes generating and transforming those C sub(1)-organosulphur compounds which are major intermediates in the biogeochemical cycling of sulphur are summarised. The biological and chemical interconversions of the methylated sulphides, methane sulphonate, carbon disulphide and carbonyl sulphide are significantly influenced by diverse microorganisms, including autotrophic thiobacilli, methylotrophs, methanogens and sulphate-reducing bacteria. The major biogenic sulphur gas is dimethyl sulphide. A major atmospheric photochemical oxidation product from this is methane sulphonate, which can contribute to the acidity of rain. New data and ideas on the microbiological fate of methane sulphonate and of natural and anthropogenic carbon disulphide are presented.
AN: 2481631
1176 of 1521
TI: (PCB in the marine environment: Biogeochemistry and ecotoxicology.).
OT: Les polychlorobiphenyles (PCB) en milieu marin: Biogeochimie et ecotoxicologie
AU: Marchand,-M.; Abarnou,-A.; Marcaillou-Lebaut,-C.
AF: IFREMER Cent. Brest, DRO/EL, B.P. 70, 29280 Plouzane, France
SO: RAPP.-SCI.-TECH.-IFREMER. PLOUZANE-FRANCE-IFREMER-CENTRE-BREST,-SERVICE-DOCUMENTATION-PUBLICATIONS 1990. no. 18, 162 pp
LA: French
ER: M (Marine)
AB: This report synthesizes the knowledge on the behaviour, bioconcentration processes and ecotoxicity of PCB in the marine environment. Contamination levels of the French coasts are examined. Concentration levels, mechanisms and fluxes between geochemical reservoirs are assessed. Emphasis is given on sublethal effects and toxicity mechanisms. Quality standards used in European Community countries are listed. Conclusions and recommendations for environmental management and research are given.
AN: 2473465
1177 of 1521
TI: Dynamics of nutrient cycling of the Valdes Bay-Punta Cero pond system (Peninsula Valdes, Patagonia) Argentina.
AU: Esteves,-J.L.; Varela,-D.E.
AF: Cent. Nac. Patagonico, Blvd. Maritimo Alte. Brown s/n, 9120, Puerto Madryn, Argentina
SO: OCEANOL.-ACTA. 1991. vol. 14, no. 1, pp. 51-58
LA: English
ER: M (Marine)
AB: Valdes Bay constitutes a very interesting land-sea interface (LSI) at Peninsula Valdes. A gravel bank separates the bay from the open sea. The general characteristics (physical, chemical and biological) of this ecosystem and the chemical composition of the seawater coming in and out were analyzed. Nutrient cycling (nitrogen and phosphate) was very intense and involved a high primary productivity. These nutrients were principally produced at the gravel bank, where oxygen was consumed by heterotrophic activity and nitrification processes. The latter process consumed 1 to 7% of the oxygen. Extrapolating to the 35-km bank, a value of 6.8 metric tons of nitrogen would be produced daily.
AN: 2473049
1178 of 1521
TI: (Anaerobic biodegradation of calcified skeletons in the marine environment: 2. Chemical approach.).
OT: Biodegradation anaerobique des structures squelettiques en milieu marin: 2. Approche chimique
AU: Simon,-A.; Poulicek,-M.; Machiroux,-R.; Thorez,-J.
AF: Lab. Morphol., Syst. Ecol. Anim., Univ. Liege, Inst. Zool., quai Van Beneden 22, 4020 Liege, Belgium
SO: CAH.-BIOL.-MAR. 1990. vol. 31, no. 3, pp. 365-384
LA: French
ER: M (Marine)
AB: The experimental approach of anaerobic biodegradation processes was undertaken in the Calvi Bay (Corsica) and in an aquarium. Three types of calcified skeletons were considered: isolated prismatic layer of Pinna nobilis (bivalvia) shell, nacreous layer of Nautilus pompilius (cephalopod) shell and stereom of Sphaerechinus granularis (echinoid) skeletal plates. The experimental material was embedded into organoclastic sand-filled closed jars retrieved periodically (1, 3, 6 or 9 months). I.C.P. and X-ray diffraction analysis, protein, chitin and enzymatic activity estimation showed that calcified skeleton biodegradation occurred very fast in anaerobiosis. Anoxic weathering was almost as fast as the aerobic one. Biodegradation patterns were very different from one type of calcified skeleton to another, caused by differences of organic matter distribution. In opposition to "classical" views, it is shown that anoxic biodegradation processes occur in very similar ways as oxic ones.
AN: 2473033
1179 of 1521
TI: (Influence of biodeposition by filter-feeding bivalves on the evolution of salt-marsh meiobenthic communities.).
OT: Influence de la biodeposition de bivalves filtreurs sur les peuplements meiobenthiques d'un marais maritime
AU: Dinet,-A.; Sornin,-J.-M.; Sabliere,-A.; Delmas,-D.; Feuillet-Girard,-M.
AF: Lab. Arago, 66650 Banyuls-sur-Mer, France
SO: CAH.-BIOL.-MAR. 1990. vol. 31, no. 3, pp. 307-322
LA: French
ER: B (Brackish)
AB: The influence of biodeposition by filter-feeding bivalves (Crassostrea gigas and Mytilus edulis ) on the evolution of salt-marsh meiobenthic communities of the French Atlantic coast was studied over a 15-month period. Quantitative variations of meiofauna were analyzed monthly and, during some phases of the year cycle, at two or three-days intervals. The reasons for the recorded faunal variations were searched by principal component analysis among the main physico-chemical factors of the environment and more especially those related to the particulate organic matter of sediments. Over the concerned period, it seemed difficult to point out the subtle effects of biodeposition on meiofauna as the seasonal factor, basically thermal, was found responsible for the largest quantitative variations observed in the communities. Nematodes and harpacticoid copepods inversely reacted to the massive input of biodeposits. Finally, the most striking effect of these was a lowering of populations very likely due to the strong reduction of the substrate (negative Eh) and a rather high content of ammonium in interstitial waters.
AN: 2472387
1180 of 1521
TI: Effects of solar ultraviolet radiation on biogeochemical dynamics in aquatic environments: Report of a workshop held in Woods Hole, Massachusetts on 23-26 October 1989.
AU: Blough,-N.V.; Zepp,-R.G.
CA: Woods Hole Oceanographic Inst., MA (USA)
SO: TECH.-REP.-WOODS-HOLE-OCEANOGR.-INST. 1990. 201 pp
NT: NTIS Order No.: AD-A221 119/1/GAR. Contract N00014-90-J-1154.
RN: WHOI-90-09 (WHOI9009)
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: To better assess the possible ramifications of changing UV levels on biogeochemical dynamics, this workshop assembled a diverse group of experts, including atmospheric chemists and physicists and aquatic chemists, biochemists and biologists. Participants were asked to help identify and more clearly define: i) the potential effects of climate change on ground level solar UV (and visible) radiation, ii) the impacts of solar UV radiation on geochemical processes in aquatic systems, iii) the effects of solar UV radiation on biological processes, with emphasis on the possible effects of enhanced UV-B (280-320 nm) radiation. Participants were asked to discuss experimental and theoretical approaches to better characterize and model these processes on both regional and global scales. Questions that were addressed at the workshop included.
AN: 2465656
1181 of 1521
TI: Savannah River Ecology Laboratory annual report for the period ending July 31, 1989. Volume 2. Appendices.
CA: Savannah River Ecology Lab., Aiken, SC (USA). Div. of Stress and Wildlife Ecology
SO: 1990. 67 pp
NT: NTIS Order No.: DE90012110/GAR.
RN: SRO-819-20-Vol.2 (SRO81920Vol2)
LA: English
ER: F (Freshwater)
AB: Opportunities to study and understand the importance of both man-induced and natural environmental stresses are available to researchers on the Savannah River Site (SRS). Energy technologies have an impact on natural habitats and the associated plant and animal communities in a variety of ways. The transport, fate, and ecological effects of a variety of chemicals such as radionuclides, organic contaminants, and trace metals must be understood. In addition, construction, forestry programs, thermal releases, and other activities that affect terrestrial and aquatic environments are recognized nationally as having major impacts. These concerns have led to a variety of questions about the consequences of SRS activities on environmental systems and form a basis for research by scientists at Savannah River Ecology Laboratory (SREL). (Contract AC09-76SR00819. Sponsored by Department of Energy, Washington, DC. Portions of this document are illegible in microfiche products.)
AN: 2465620
1182 of 1521
TI: Annual report of ecological research for the period ending July 31, 1989. Volume 1. Main report.
CA: Savannah River Ecology Lab., Aiken, SC (USA). Div. of Stress and Wildlife Ecology
SO: 1990. 25 pp
NT: NTIS Order No.: DE90012109/GAR.
RN: SRO-819-20-Vol. 1 (1)
LA: English
ER: F (Freshwater)
AB: Opportunities to study and understand the importance of both man-induced and natural environmental stresses are available to researchers on the Savannah River Site (SRS). These concerns have led to a variety of questions about the consequences of SRS activities on environmental systems and form a basis for research by scientists at Savannah River Ecology Laboratory (SREL). Research at SREL can involve a variety of approaches, including field research, research in controlled environments such as greenhouses, and laboratory studies that require the use of sophisticated instrumentation. Highlights of research activities during FY89 at SREL over the past year are presented. Complete abstracts of specific projects are appended. (Contract AC09-76SR00819. Sponsored by Department of Energy, Washington, DC. Portions of this document are illegible in microfiche products.)
AN: 2465586
1183 of 1521
TI: Eutrophication in Hiroshima Bay.
AU: Seiki,-T.; Date,-E.; Izawa,-H.
AF: Hiroshima Prefect. Res. Cent. Environ. Sci., 1-6-29, Minami-machi, Minami-ku, Hiroshima 734, Japan
CO: Int. Conf. on the Environmental Management of Enclosed Coastal Seas '90: EMECS '90, Kobe, Hyogo Prefect. (Japan), 3-6 Aug 1990
SO: ENVIRONMENTAL-MANAGEMENT-AND-APPROPRIATE-USE-OF-ENCLOSED-COASTAL-SEAS-EMECS-'-90. Goda,-T.;et-al.-eds. 1991. vol. 23 pp. 95-99
ST: MAR.-POLLUT.-BULL. vol. 23
LA: English
ER: M (Marine)
AB: Several researches for eutrophication in the northern Hiroshima Bay were carried out to investigate nutrient budgets in aquatic circulation processes, i.e. primary production, settling flux of particulate organic matter (POM) and the benthic remineralization. It became apparent from these investigations that primary production contributed to the organic pollution in the northern bay than land based organic loadings by a factor of 10, that approx. 70-80% of the POM originating in phytoplankton were easily remineralized into inorganic nutrients during the settling process in water, and that approx. 60% of nitrogen and 70% of phosphorus in POM settled on the sediments might be returned to the water column by the release from benthic sediment.
AN: 2463112
1184 of 1521
TI: Creation of a new nonfeeding aquaculture system in enclosed coastal seas.
AU: Inui,-M.; Itsubo,-M.; Iso,-S.
AF: Tech. Cent., Tokyo Kyuei Co., Ltd., Saitama Prefect., Kawaguchi City, Shiba-tsurugamaru 6906-10, Japan
CO: Int. Conf. on the Environmental Management of Enclosed Coastal Seas '90: EMECS '90, Kobe, Hyogo Prefect. (Japan), 3-6 Aug 1990
SO: ENVIRONMENTAL-MANAGEMENT-AND-APPROPRIATE-USE-OF-ENCLOSED-COASTAL-SEAS-EMECS-'-90. Goda,-T.;et-al.-ed.. 1991. vol. 23 pp. 321-325
ST: MAR.-POLLUT.-BULL. vol. 23
LA: English
ER: M (Marine)
AB: Eutrophication has occurred in the enclosed coastal seas, presenting a serious environmental problem. To prevent such a situation, we propose to create a new biogeochemical, recycle system whereby nutrients flowing into the seas would be returned to land by means of a combined system of aquacultures of non-feeding type. The system consists of culture of seaweeds, culture of filter feeding animals, and culture of mud feeding animals. However, the development of culture in the enclose coastal seas inevitably leads to overproduction. To promote and sustain the system, it is important not only to develop the industrial utilization of each of the cultured products, but also set up an organization of cooperations between the fishery cooperatives, local citizens and local governments.
AN: 2462117
1185 of 1521
TI: Scavenging processes of marine particles in Osaka Bay.
AU: Montani,-S.; Mishima,-Y.; Okaichi,-T.
AF: Dep. Bioresour. Sci., Fac. Agric., Kagawa Univ., Miki, Kagawa 761-07, Japan
CO: Int. Conf. on the Environmental Management of Enclosed Coastal Seas '90: EMECS '90, Kobe, Hyogo Prefect. (Japan), 3-6 Aug 1990
SO: ENVIRONMENTAL-MANAGEMENT-AND-APPROPRIATE-USE-OF-ENCLOSED-COASTAL-SEAS-EMECS-'-90. Goda,-T.;et-al.-eds. 1991. vol. 23 pp. 107-111
ST: MAR.-POLLUT.-BULL. vol. 23
LA: English
ER: M (Marine)
AB: The scavenging processes of marine particles in Osaka Bay was investigated using bioelement (C,N,P) distribution as an indicator. Nutrient concentrations in the water and bioelement contents in suspended particles, sinking particles and surface sediment were monitored for three years (1985 to 1987). Large variations appeared to depend on environmental conditions. Bioelement concentrations in suspended particles and sinking particles decrease remarkably going from the inner part of the bay to the offshore water area. Our results suggested that the position of the tidal front in Osaka Bay agrees very closely with 20-30 m water depth; the chemical character of suspended particles and sinking particles was considerably different from across the tidal frontal area. According to the chemical character of sinking particles at the offshore water area station, these particles are mainly made up of "old particles" of which the labile organic matter fraction was already decomposed. Sedimentation of nitrogen in the inner part of the bay accounts for approximately 6% of all nitrogen inputs to Osaka Bay.
AN: 2461904
1186 of 1521
TI: Impact of nutrient enrichment and their relation to the algal bloom in the Adriatic Sea.
AU: Vukadin,-I.
AF: Inst. Oceanogr. and Fish., 58000 Split, Yugoslavia
CO: Int. Conf. on the Environmental Management of Enclosed Coastal Seas '90: EMECS '90, Kobe, Hyogo Prefect. (Japan), 3-6 Aug 1990
SO: ENVIRONMENTAL-MANAGEMENT-AND-APPROPRIATE-USE-OF-ENCLOSED-COASTAL-SEAS-EMECS-'-90. Goda,-T.;et-al.-eds. 1991. vol. 23 pp. 145-148
ST: MAR.-POLLUT.-BULL. vol. 23
LA: English
ER: M (Marine)
AB: Extraordinary manifestations of eutrophication in the Adriatic Sea during the last few years have been due to the combined effects of different physico-chemical and meteorological factors. Permanent inputs of nutrients, particularly in the northern Adriatic via river runoffs and municipal sewage during calm summers, cause marked stratification of the water column and reduction of horizontal advection. These two effects provide the ideal conditions for single a species bloom. An attempt has been made to calculate the nutrient balance which allows a better interpretation of algal blooms in the Adriatic.
AN: 2461673
1187 of 1521
TI: Nitrogen forms in the South Atlantic.
OT: Formy azota v Yuzhnoj Atlantike
AU: Arzhanova,-N.V.; Zubarevich,-V.L.; Naletova,-I.A.
AF: VNIRO, Moscow, USSR
SO: OKEANOLOGIYA-OCEANOLOGY. 1990. vol. 30, no. 6, pp. 936-944
LA: Russian
ER: M (Marine)
AB: Spatial distribution of mineral and organic forms of N and relations between the 2 forms in the water column is considered for various latitudinal zones of the South Atlantic. It is stated that a considerable decrease in the total content of mineral forms of N from Antarctica to the equator (from 15-30 down to 1 mu g-at/l in the photic layer) the N sub(org) level was maintained at 15-20 and 10-20 mu g-at/l at the surface and in deeper layers respectively. High concentrations of N (> 30 and > 20 mu g-at/l at the surface and in deeper layers respectively were typical of the Antarctic Convergence and subtropical anticyclonic zones). The contribution of urea N and aminoacids to the total N sub(org) was found to vary from 5 to 30 and 20% respectively.
AN: 2459303
1188 of 1521
TI: (Basic provisions of the theory of functioning of aquatic ecosystems.).
OT: Osnovnye polozheniya teorii funktsionirovaniya vodnykh ehkosistem
AU: Alimov,-A.F.
AF: ZIN AN SSSR, Leningrad, USSR
SO: GIDROBIOL.-ZH.-HYDROBIOL.-J. 1990. vol. 26, no. 6, pp. 3-12
LA: Russian
AB: The paper reviews the major points of the theory of functioning of water ecosystems which is regarded as a variable interaction of fluxes of energy, matter and information which ensure stability of these systems under specific conditions. Stability is a relatively constant value of the average structural and functional characteristics in specific conditions for a sufficiently long period of time. The author considers the potential ways of studying the structure, formation and interaction of energy, matter and information fluxes from the angle of the theories of biological production, of information and thermodynamics.
AN: 2459020
1189 of 1521
TI: Ocean-atmosphere interactions in the global biogeochemical sulfur cycle.
AU: Andreae,-M.O.
AF: Biogeochem. Dep., Max Planck Inst. Chem., P.O. Box 3060, D-6500 Mainz, FRG
CO: 32. IUPAC Congr. in the Section on Atmospheric and Marine Chemistry, Stockholm (Sweden), 2-7 Aug 1989
SO: MAR.-CHEM. 1990. vol. 30, no. 1-3, pp. 1-29
NT: Special issue.
LA: English
ER: M (Marine)
AB: Marine algae produce dimethylsulfonium propionate, which may be enzymatically cleaved to yield the volatile dimethylsulfide (DMS). There are no simple relationships with algal biomass or primary productivity, but the concentration of DMS in the ocean is regulated by a complicated interplay of algal speciation and trophic interactions. Part of the biogenically produced DMS diffuses into the atmosphere, where it is oxidized, mostly to aerosol sulfate. The ability of these aerosol particles to nucleate cloud droplets, and thereby influence the reflectivity and stability of clouds, forms the basis of a proposed geophysiological feedback loop involving phytoplankton, atmospheric sulfur, and climate. Carbonylsulfide (COS) is produced photochemically from dissolved organic matter in seawater. Diffusion of COS from the ocean to the atmosphere is a globally significant source of this gas, which participates in the stratospheric ozone cycle. Hydrogen sulfide and carbon disulfide are produced in the surface ocean, but the oceans are a minor source to the troposphere.
AN: 2453079
1190 of 1521
TI: Chemical processes at the sediment-water interface.
AU: Santschi,-P.; Hoehener,-P.; Benoit,-G.; Buchholtz-ten-Brink,-M.
AF: Texas A&M Univ., Galveston, TX 77553-1675, USA
CO: 32. IUPAC Congr. in the Section on Atmospheric and Marine Chemistry, Stockholm (Sweden), 2-7 Aug 1989
SO: MAR.-CHEM. 1990. vol. 30, no. 1-3, pp. 269-315
NT: Special issue.
LA: English
ER: M (Marine)
AB: Discusses chemical transformations that take place during early diagenesis in sediments, and which are fueled by supply rates of organic carbon and electron acceptors. Current knowledge of the cycling of the electron acceptors O, N, Mn, Fe and S is assessed, and the important role of transport reactions described. Elemental fluxes across the sediment-water interface can be described from first principles only if the coupling of physical, chemical and biological processes is better understood. Chemical reactions within this region must be considered an integral part of a three-dimensional network of interactions. Hence, the apparent coexistence of chemical species considered "incompatible" by thermodynamic models can be a consequence of the three-dimensional nature of redox gradients. The microbiological, chemical and physical interactions of dissolved, colloidal and particulate organic carbon, and iron and manganese oxides play a crucial role in the early diagenetic reactions at the sediment-water interface. Their effects on diagenetic reactions, and on trace elements in solution and adsorbed to particles, are discussed. Furthermore, we emphasize the way in which hydrodynamics can control elemental fluxes in environments with high carbon rain rates.
AN: 2452902
1191 of 1521
TI: Importance of continental margins in the marine biogeochemical cycling of carbon and nitrogen.
AU: Walsh,-J.J.
AF: Dep. Mar. Sci., Univ. South Florida, 140 7th Ave. S., St. Petersburg, FL 33701, USA
SO: NATURE. 1991. vol. 350, no. 6313, pp. 53-55
LA: English
ER: M (Marine)
AB: The continental margins occupy less than 20% of the surface area of the world ocean, and it is widely assumed that they do not play a significant part in the oceanic biogeochemical cycles of carbon and nitrogen. Data from 32 sediment-trap moorings, 16 in the deep sea and 16 on the continental slope, suggest that at an average depth of 2,650 m on the slope, the combined rain of surviving shelf and slope particles yields a mean carbon flux of 6.9 g C/m super(2)/yr - about ten times that at the same average depth in the deep sea (0.8 g C/m super(2)/yr). Because the area of the deep sea is about ten times greater than that of the continental slopes, using the sediment-trap data and assuming a carbon/nitrogen ratio of 5:1, the equivalent total particulate offshore nitrogen loss is 0.5 x 10 super(14) g N/yr at 2,650 m. If these trap observations are generally representative of the oceans and continental margins, then the supply of dissolved nitrate to the overlying euphotic zones should also be similar. Here I provide an independent estimate of the annual supply of onwelling nitrate from the deep sea to the shelves and find that it may balance the offshore flux of carbon, suggesting that the continental margins and deep sea are equally important in the carbon and nitrogen biogeochemical cycles.
AN: 2449252
1192 of 1521
TI: Nitrogen, phosphorus, and biogenic silicon budgets for the northern Adriatic Sea.
AU: Degobbis,-D.; Gilmartin,-M.
AF: Rudjer Boskovie Inst., Cent. Mar. Res., 52210 Rovinj, Yugoslavia
SO: OCEANOL.-ACTA. 1990. vol. 13, no. 1, pp. 31-45
LA: English
ER: M (Marine)
AB: Proximate nitrogen, phosphorus and biogenic silicon budgets were calculated for the northern Adriatic, one of the most productive subregions of the Mediterranean Sea, and the main processes driving the biogeochemical cycle of these biogenic elements were ranked as to their relative importance. The results support the assumed importance of the nutrient contribution by the Po River (at least 50% of the inputs) whose waters thereby influence a large part of the northern Adriatic.
AN: 2448473
1193 of 1521
TI: Dynamics and controls of methane oxidation in a Danish wetland sediment.
AU: King,-G.M.
AF: Darling Mar. Cent., Univ. Maine, Walpole, ME 04573, USA
SO: FEMS-MICROBIOL.-ECOL. 1990. vol. 74, no. 4, pp. 309-324
LA: English
ER: F (Freshwater)
AB: The patterns and controls of methane oxidation in a Danish wetland sediment have been determined using a combination of slurry and intact core techniques. Results from slurries indicated that methane oxidation was effectively inhibited by low concentrations of nitrapyrin (9 mu M) and acetylene (0.5 mu M) but that oxidation was relatively insensitive to pH between 6 and 8; in addition, high concentrations of ammonia (1 mM) decreased oxidation, especially at alkaline pH. Kinetic analyses of methane oxidation in slurries indicated that V sub(max) was high relative to values reported for other sediments, that V sub(max) changed seasonally, that K sub(m) was consistently low (2-4 mu M) and that threshold values were low (3-5 nM) but insufficient to allow consumption of atmospheric methane. Analyses based on intact cores indicated that the extent of methane oxidation was highly dependent on oxygen availability, particularly as affected by benthic photosynthesis or the presence of algal mats.
AN: 2447638
1194 of 1521
TI: Biological removal of dimethyl sulphide from sea water.
AU: Kiene,-R.P.; Bates,-T.S.
AF: Univ. Georgia Mar. Inst., Sapelo Island, GA 31327, USA
SO: NATURE. 1990. vol. 345, no. 6277, pp. 702-705
LA: English
ER: M (Marine)
AB: Dimethyl sulphide (DMS) is an important sulphur-containing trace gas in the atmosphere. Relatively little is known about the biogeochemical and physical processes that control the concentration of DMS in sea water. Here we present data from incubation experiments, carried out at sea, which show that DMS is removed by microbial activity. In the eastern, tropical Pacific Ocean, DMS turnover is dominated by biological processes, with turnover times for biological DMS removal generally more than ten (3-430) times faster than turnover by ventilation to the atmosphere. The results have significant implications for climate feedback models involving DMS emissions, and highlight the importance of the microbial food web in oceanic DMS cycling.
AN: 2447583
1195 of 1521
TI: Sequentially extracted metals in Adirondack lake sediment cores.
AU: White,-J.R.; Gubala,-C.P.
AF: Sch. Pub. and Environ. Aff., Indiana Univ., Bloomington, IN 47405, USA
SO: J.-PALEOLIMNOL. 1990. vol. 3, no. 3, pp. 243-252
LA: English
ER: F (Freshwater)
AB: Metal deposition patterns have been examined in sediment cores from 3 lakes in the Adirondack region of New York (USA). Sequential chemical extraction of Al, Fe, Mn, Pb, and Zn has yielded information on their chemical nature and potential mechanisms involved in their deposition. Results indicate historical changes in watershed chemistry may have influenced metal chemistry in these lakes. In two systems known to have been acidified in recent time by acidic deposition (Big Moose L. & Deep L.), concentrations of labile Al (in Cl-C4 fraction) increase after 1940-1950, corresponding with lake acidification as inferred from diatom assemblages. Chemical stratigraphies of Fe and Mn are most likely dominated by internal biogeochemical cycling within sediments.
AN: 2447343
1196 of 1521
TI: TOXIWASP.
AU: Schramm,-K.-W.
AF: Dep. Ecol. Chem. and Geochem., Univ. Bayreuth, Bayreuth, FRG
SO: TOXICOL.-ENVIRON.-CHEM. 1990. vol. 26, no. 1-4, pp. 55-60
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: TOXIWASP combines most of the kinetic structure of EXAMS 2 with the transport capabilities of WASP (Water Analysis Simulation Program). TOXIWASP uses variable chemical degradation rates from chemical properties and the environmental conditions of the aquatic ecosystem. These rates are reduced from pseudo first-order rates to first-order rates including the processes hydrolysis, biotransformation, phototransformation, oxidation, and volatilisation. Assuming ultimate local equilibrium, and using a chemical dependent partition coefficient as well as spatially varying environmental carbon fractions, sorption onto sediments and biomass is calculated. Environmental alternations could be specified in any time scale by providing monitoring data. TOXIWASP generates total sediment and chemical concentrations every time step in every segment, including surface water, subsurface water, surface bed and subsurface bed. Advection, dispersion, mass loading, sedimentation, and scour affect sediment concentration in the water column and in the bed sediment concentrations depend on burial and erosion. In addition chemical concentrations are influenced by degradation, sediment-water dispersion, and percolation. Lateral transport of chemical within the bed is neglected and transport data are not calculated in the program.
AN: 2444591
1197 of 1521
TI: A nitrogen-based model of plankton dynamics in the oceanic mixed layer.
AU: Fasham,-M.J.R.; Ducklow,-H.W.; McKelvie,-S.M.
AF: Inst. Oceanogr. Sci., Deacon Lab., Nat. Environ. Res. Counc., Brook Rd., Wormley, Godalming GU8 5UB, UK
SO: J.-MAR.-RES. 1990. vol. 48, no. 3, pp. 591-639
LA: English
ER: M (Marine)
AB: As a first step toward the development of coupled, basin scale models of ocean circulation and biogeochemical cycling, the authors present a model of the annual cycles of plankton dynamics and nitrogen cycling in the oceanic mixed layer. The model is easily modified and runs in FORTRAN on a personal computer. In our initial development and exploration of the model's behavior we have concentrated on modeling the annual cycle at Station "S" near Bermuda using seven compartments (Phytoplankton, Zooplankton, Bacteria, Nitrate, Ammonium, Dissolved organic nitrogen and Detritus). This choice of compartments and the attendant flows permits a functional distinction between new and regenerated production. We have examined over 200 different runs and carried out sensitivity analyses. These model runs reproduce the annual cycles of areal NPP, an average annual NPP, new production, and particulate N flux values reported in the literature. The model demonstrates that currently accepted values for these annual fluxes can be reconciled only if the f-ratio has a high annual average. At present, the annual average f-ratio is poorly quantified due to undersampling in fall and winter.
AN: 2443163
1198 of 1521
TI: On the biochemical degradation of urea in aqueous solution--review.
OT: Zum biochemischen Harnstoffabbau in waessriger Loesung--Uebersicht
AU: Gunkel,-K.; Kuemmel,-R.; Tuempling,-W.V.
AF: Berirkshygieneinsp. und -Inst. Max von Pettenkofer, Juri-Gagarin-Ring 124, Erfurt, 5020, FRG
SO: ACTA-HYDROCHIM.-HYDROBIOL. 1990. vol. 18, no. 1, pp. 3-20
LA: German
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Urea from natural and anthropogenic sources is one of the most interesting nitrogen compounds in an aquatic environment. Results of experimental investigations are presented for the successive biochemical urea transformation into nitrates via ammonium and nitrite species. Kinetic models based on a combination of Michaelis-Menten and Monod equations have been derived which describe reasonably well the course of the enzymatic reactions and the concentration-time profiles of different N oxidation states. Main factors affecting the rates of nitrogen metabolization are the initial concentration of ureolytic bacteria, the physical state of the nitrifying microorganisms, and the concentration of toxic organics added to the system under study.
AN: 2441473
1199 of 1521
TI: EXAMS 2. EXposure Analysis Modeling System.
AU: Schramm,-K.-W.
AF: Dep. Ecol. Chem. and Geochem., Univ. Bayreuth, Bayreuth, FRG
SO: TOXICOL.-ENVIRON.-CHEM. 1990. vol. 26, no. 1-4, pp. 73-82
LA: English
AB: EXAMS 2 was developed by Burns et al. for rapid evaluation of the behavior of organic chemicals in aquatic ecosystems. EXAMS 2 computes from the chemistry and the relevant transport and physicochemical properties of the compounds and the ecosystem: Expected environmental concentrations. The fate of chemicals due to transport and transformation processes. The persistence of chemicals in the systems once chemical loadings terminate. The program is interactive and allows the user to define and store the properties of the chemicals and environments. Loadings, transport, and transformations are combined into a set of differential equations assuming conservation of mass. Entering and leaving chemical mass into and from the environment is treated as the algebraic sum of external loadings, transport processes that export chemicals from the system, and transformation processes that convert chemicals to their transformation products. Water bodies can be combined via a set of several compartments or distinct zones of the environment as benthic, epilimnic, hypolimnic, and littoral subzones. EXAMS 2 accepts standard water-quality and limnological parameters.
AN: 2441428
1200 of 1521
TI: MESEP: Modelling environmental scenarios in ponds.
AU: Schramm,-K.-W.; Goss,-K.-U.
AF: Dep. Ecol. Chem. and Geochem., Univ. Bayreuth, Bayreuth, FRG
SO: TOXICOL.-ENVIRON.-CHEM. 1990. vol. 26, no. 1-4, pp. 123-128
LA: English
ER: F (Freshwater)
AB: MESIP is fugacity model which can predict the fate of organic hydrophobic chemicals in aquatic ecosystems. In this paper a short introduction to the mathematical model is presented together with a more detailed listing of the required input data. Comparison of the calculated and measured fate of a fluorescent whitening compounds in an artificial outdoor pond is shown.
AN: 2441243
1201 of 1521
TI: (Mercury in the marine environment: Biogeochemistry and ecotoxicology.).
OT: Le mercure en milieu marin: Biogeochimie et ecotoxicologie
AU: Cossa,-D.; Thibaud,-Y.; Romeo,-M.; Gnassia-Barelli,-M.
AF: IFREMER Cent. Nantes, B.P. 1049, 44037 Nantes Cedex, France
SO: RAPP.-SCI.-TECH.-IFREMER. 1990. no. 19, 130 pp
LA: French
ER: M (Marine)
AB: This report synthesizes the knowledge on the biogeochemical cycle, bioconcentration processes and ecotoxicity of mercury in the marine environment. Man induced changes on the mercury cycle, especially along the French coasts, are reviewed. Concentration levels, mechanisms and fluxes between geochemical reservoirs are assessed. Emphasis is given on sublethal effects and toxicity mechanisms. Quality standards used in European Community countries are listed. Conclusions and recommendations for environmental management and research are given.
AN: 2440884
1202 of 1521
TI: Bacterial regeneration of ammonium and phosphate as affected by the carbon:nitrogen:phosphorus ratio of organic substrates.
AU: Tezuka,-Y.
AF: Otsu Hydrobiol. Stn., Kyoto Univ., Shimosakamoto, Otsu 520-01, Japan
SO: MICROB.-ECOL. 1990. vol. 19, no. 3, pp. 227-238
LA: English
ER: F (Freshwater)
AB: The effect of carbon: nitrogen: phosphorus (C:N:P) ratio of organic substrates on the regeneration of ammonium and phosphate was investigated by growing natural assemblages of freshwater bacteria in mineral media supplemented with the simple organic C, N, and P sources (glucose, asparagine, and sodium glycerophosphate, respectively) to give 25 different substrate C:N:P ratios. Both ammonium and phosphate were regenerated when C:N and N:P atomic ratios of organic substrates were less than or equal to 10:1 and less than or equal to 16:1, respectively. Only ammonium was regenerated when C:N and N:P ratios were less than or equal to 10:1 and greater than or equal to 10-20:1, respectively. On the other hand, neither ammonium nor phosphate was regenerated when C:N and N:P ratios were greater than or equal to 15:1 and greater than or equal to 5:1, respectively. In no case was phosphate alone regenerated. As bacteria were able to alter widely the C:N:P ratio of their biomass, the growth yield of bacteria appeared primarily dependent on the substrate carbon concentration, irrespective of a wide variation in the substrate C:N:P ratio.
AN: 2439238
1203 of 1521
TI: (Antarctic ice record: Climate and atmosphere evolution over the last climatic cycle.).
OT: Archives glaciaires de l'Antarctique: Climat et environnement atmospherique au cours du dernier cycle climatique
AU: Raynaud,-D.
AF: Lab. Glaciol. et Geophys. Environ., CNRS, B.P. 96, 38402 St Martin d'Heres Cedex, France
SO: OCEANOLOGY:-EVENTS,-FUTURE-AND-PREDICTION.. OCEANOLOGIE:-ACTUALITE-ET-PROSPECTIVE. Denis,-M.-ed. 1989. pp. 155-167
LA: French
ER: M (Marine)
AB: The advantages and limitations of the ice record are discussed and compared with the oceanic record. Three main aspects of the Antarctic ice record over the last climatic cycle are presented: the evolution of atmospheric temperature in Antarctica, the evolution of two important greenhouse gases (CO sub(2) and CH sub(4)) and evolution of various aerosols of different origins. The results indicate the close interactions between biogeochemical cycles, atmospheric composition and climate.
AN: 2437344
1204 of 1521
TI: The coral reef: An owner-built, high-density, fully-serviced, self-sufficient housing estate in the desert - or is it?.
AU: Kinsey,-D.W.
AF: Great Barrier Reef Mar. Park Auth., Townsville, Qld. 4810, Australia
CO: Joint Israel-U.S. Workshop on Marine Symbiosis: From Molecular Biology to Ecosystem Function, Eilat (Israel), 11-16 Mar 1990
SO: SYMBIOSIS. 1991. vol. 10, no. 1-3, pp. 1-22
LA: English
ER: M (Marine)
AB: Coral reefs usually are portrayed as the ultimate example of exosystem symbiosis and organisation. It has been suggested that this extreme of integration, and perhaps predictability, is the result of necessity in the "desert" of the oceanic world. Actually, reefs do not need to live in oceanic deserts. In fact, it is doubtful whether the oligotrophic oceans are as desert-like as once supposed. Reefs develop in a wide range of nutrient environments, and the resulting configuration is extremely variable on all scales from gross reef morphology down to detailed community structure. Nevertheless, the majority of reefs have very predictable zonation, zonal width, sources and sink areas, and community metabolic rates. The paper examines the development of the author's "philosophy" of reef biogeochemical performance over 30 years and also draws heavily on ideas developed by S.V. Smith.
AN: 2431798
1205 of 1521
TI: Impacts of forests on water chemistry.
AU: Mahendrappa,-M.K.
AF: For. Canada, Marit. Reg., P.O. Box 4000, Fredericton, N.B. E3B 5P7, Canada
CO: Symp. on the Acidification of Organic Waters in Kejimkujik National Park, Nova Scotia, Canada, Wolfville, N.S. (Canada), 25-27 Oct 1988
SO: WATER-AIR-SOIL-POLLUT. 1989. vol. 46, no. 1-4, pp. 61-72
LA: English
ER: F (Freshwater)
AB: Forest canopies and soil organic horizons have been identified as 2 major components of forest ecosystems interacting with and altering the chemistry of rainwater. Data, collected over a 13-yr period from different softwood and hardwood stands located in central New Brunswick, are presented to demonstrate differences among stands in their ability to alter the chemistry of rainwater. In both the canopies and the soil organic horizons, retention and exchange processes are affective in altering the chemistry of rainwater. Significant species effects are recognized in the partitioning of rainwater into throughfall, stemflow, and interception, and in altering of its chemistry. Stemflow components generally contribute to acidity, while throughfall reduces acidity of rainwater. Some of the chemical characteristics of rainwater reaching the forest floor are shown to be similar to those of streams associated with the forest stands.
AN: 2429129
1206 of 1521
TI: Carbon and nitrogen budgets of the Arabian Sea.
AU: Somasundar,-K.; Rajendran,-A.; Kumar,-M.D.; Gupta,-R.S.
AF: Natl. Inst. Oceanogr., Dona Paula, Goa 403 004, India
SO: MAR.-CHEM. 1990. vol. 31, no. 4, pp. 363-377
LA: English
ER: M (Marine)
AB: From the available data, carbon and nitrogen budgets have been estimated for the Arabian Sea (0-25 degree N, 50-80 degree E), taking into consideration the possible sources of fluxes. By our model calculations the annual fluxes into and out of the Arabian Sea were estimated to be 446 and 530 trillion grams (Tg) for carbon, and 8.06 and 3.60 Tg for nitrogen, respectively. The carbon budget was found to be negatively balanced by 84 Tg/year. A possible source to compensate for this deficit could be from the northward movement of Antarctic Bottom Water in the bottom layers, which are probably enriched with anthropogenic carbon dioxide. Annually, similar to 74 Tg of carbon in the form of carbon dioxide escaped into the atmosphere from the Arabian Sea; this is higher than the global average fluxes from the tropical oceans. The percentage loss of carbon (14.0%) to the atmosphere was much lower than that of nitrogen (56.9%). Out of the total amount of denitrified nitrogen (29.5 Tg) only similar to 7% was lost to the atmosphere. This model suggests that similar to 6 Tg N/year of denitrified nitrogen of the world's oceans could be liberated to the atmosphere through the surface layer of denitrified areas.
AN: 2428239
1207 of 1521
TI: Nd isotopes as tracers in water column particles: The western Mediterranean Sea.
AU: Grousset,-F.E.; Henry,-F.; Minster,-J.F.; Monaco,-A.
AF: UA CNRS 197, Dep. Geol.-Oceanogr., Univ. Bordeaux I, Ave. Facultes, 33405 Talence Cedex, France
SO: MAR.-CHEM. 1990. vol. 31, no. 4, pp. 389-407
LA: English
ER: M (Marine)
AB: Measurements of Nd isotopic ratios in sediment trap materials are reported on samples obtained from the western Mediterranean Sea margin (Gulf of Lions). Trap samples from two different seasons were examined. For the summer-autumn series (Oct), the fluvial inputs are relatively weak, and the Saharan aerosol influence is clearly identified in the particles trapped in the surface water (0-100 m). Isotopic ratios can be explained by a mixture of low values, corresponding to Saharan detrital aerosol particles, with higher radiogenic ratios similar to values reported earlier for the Mediterranean watermass, which are carried by biogenic particulate components. On the other hand, bottom layers are more probably invaded by particles coming from the shelf and the neighbouring rivers. For the winter-spring series (Mar), high particle fluxes coming from the distant Rhone river and advected along the shelf and margin by ocean currents, are the dominant component in the surface and intermediate trap-samples. However, the near-bottom particulate flux and the sediments reflect the more local river signature.
AN: 2425029
1208 of 1521
TI: Phycological reviews 2: The role of dissolved organic nitrogen in phytoplankton nutrition, cell biology and ecology.
AU: Antia,-N.J.; Harrison,-P.J.; Oliveira,-L.
AF: Dep. Bot., Univ. British Columbia, Vancouver, B.C. V6T 2B1, Canada
SO: PHYCOLOGIA. 1991. vol. 30, no. 1, pp. 1-89
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: This review aims to cover all conceivable aspects of both marine and freshwater dissolved organic nitrogen (DON) from the moment of its inception (through release by various aquatic organisms) to its assimilation (and utilization as nutrient) by phytoplankton, to its metabolism and consequent impact on cell biology, and its ultimate turnover within the framework of ecological interactions. Attention is focused on DON vis-a-vis phytoplankton while dealing with the above mentioned aspects, although DON is also known to play various roles in the biology of heterotrophic bacteria and protozoa.
AN: 2423373
1209 of 1521
TI: Bioturbation and manganese cycling in hemipelagic sediments.
AU: Aller,-R.C.
AF: Mar. Sci. Res. Cent., SUNY, Stony Brook, NY 11794-5000, USA
CO: The Deep Sea Bed: Its Physics, Chemistry and Biology. A Discussion, London (UK), 5-6 Apr 1989
SO: THE-DEEP-SEA-BED:-ITS-PHYSICS,-CHEMISTRY-AND-BIOLOGY. Charnock,-H.;Edmond,-J.M.;McCave,-I.N.;Rice,-A.L.;Wilson,-T.R.S.-eds. 1990. vol. 331 pp. 51-68
ST: PHILOS.-TRANS.-R.-SOC.-LOND.,-A. vol. 331
LA: English
ER: M (Marine)
AB: The activities of infaunal macrobenthos have major influences on the types, rates and distributions of diagenetic reactions involving manganese in relatively carbon-rich deep-sea and nearshore sediments. In some non-sulphidic hemipelagic deposits of the eastern equatorial Pacific (Panama Basin) biogenic reworking drives internal cycles of manganese, which can apparently account for up to ca. 100% of organic carbon oxidation and reduction of O sub(2) supplied (diffusively) to the sea floor. The occurrence and geometry of manganese oxide encrusted biogenic structures imply specific adaptations of infauna to manganese based microbial activity in hemipelagic sediments like the Panama Basin.
AN: 2423145
1210 of 1521
TI: Bacterial biomass and activity in deep sediment layers from the Peru margin.
AU: Parkes,-R.J.; Cragg,-B.A.; Fry,-J.C.; Herbert,-R.A.; Wimpenny,-J.W.T.
AF: Dep. Geol., Univ. Bristol, Wills Memorial Build., Queen's Rd., Bristol BS8 1RJ, UK
CO: The Deep Sea Bed: Its Physics, Chemistry and Biology. A Discussion, London (UK), 5-6 Apr 1989
SO: THE-DEEP-SEA-BED:-ITS-PHYSICS,-CHEMISTRY-AND-BIOLOGY. Charnock,-H.;Edmond,-J.M.;McCave,-I.N.;Rice,-A.L.;Wilson,-T.R.S.-eds. 1990. vol. 331 pp. 139-153
ST: PHILOS.-TRANS.-R.-SOC.-LOND.,-A. vol. 331
LA: English
ER: M (Marine)
AB: The distribution of bacterial biomass and activity down to 80 m below the sea floor was investigated in sediments from the Peru margin, collected as part of the Ocean Drilling Programme, leg 112. Bacteria were present in all sediment depths sampled. Although direct bacterial counts decreased with depth there was no indication of a more rapid decline in the deeper layers and thus it is likely that bacteria should be present to much greater depths than those examined in this study. A significant number of the bacteria within the sediment were dividing and hence the bacteria were active and not just surviving. Bacteria were able to be cultured in laboratory media, from all depths, further confirming the viability of these organisms in situ. Bacterial sulphate reduction and methanogenesis were measured even in the deepest samples, although there were marked changes in rates with depth. There were also significant changes in the dominant populations of different types of viable bacteria and their associated activity with sediment depth.
AN: 2423104
1211 of 1521
TI: The role of lesser snow geese as nitrogen processors in a sub-arctic salt marsh.
AU: Ruess,-R.W.; Hik,-D.S.; Jefferies,-R.L.
AF: Biol. Res. Lab., 130 College Place, Syracuse Univ., Syracuse, NY 13244, USA
SO: OECOLOGIA. 1989. vol. 79, no. 1, pp. 23-29
LA: English
ER: M (Marine)
AB: Ammonia volatilization losses from faeces of lesser snow geese (Chen caerulescens caerulescens ) were measured during the summer of 1987 on the salt-marsh flats at La Perouse Bay. Amounts of ammonia volatilized increased with increasing ambient temperature, and ranged from 1.0 to 15.1 mg N/100 mg of nitrogen present as soluble ammonium ions at the start of the 8-h experiment. Using estimates of faecal deposition reported previously, the annual loss via volatilization was estimated at 0.08 g N/m super(2), or 7.9% of the nitrogen present in goose faeces. Percent change in soluble ammonium ions in fresh faeces after 8 h ranged from -51.1% to +41.1%, indicating that net mineralization of organic nitrogen occurred in some of the faeces. Microbial respiration of fresh goose faeces increased exponentially with temperature. However, variable rates of net mineralization per unit rate of respiration indicated that the substrate quality affected microbial immobilization and thus net nitrogen mineralization.
AN: 2423103
1212 of 1521
TI: Heterotrophic bacterial populations and primary production in fish ponds under different management practices.
AU: Ayyappan,-S.; Purushothaman,-C.S.; Saha,-P.K.; Pani,-K.C.
AF: Cent. Inst. Freshwater Aquacult., Kausalyagang, Bhubaneswar-751 002, Orissa, India
SO: J.-AQUACULT.-BHUBANESWAR. 1991. vol. 1, pp. 11-29
LA: English
ER: F (Freshwater)
AB: Aerobic heterotrophic bacterial populations in water and sediment and primary production of carp polyculture ponds under different management practices, viz., fortnightly application of cowdung in heaps, spray-application of cowdung on alternate days, gradual leaching of inorganic fertilizers, manual raking of pond bottom and bioturbation by common carp, (Cyprinus carpio ), were studied along with growth of bacterial populations under simulated conditions. Bacterial counts were maximal in ponds with agitated bottom, in spite of absence of allochthonous organic enrichment. Generation time and generation number of the population in the water and sediment media were in the ranges of 0.9-24.8 h, 0.7-21.2 h and 0.2-5.3, 0.2-6.4 resp., indicating intense bacterial activities. Primary production levels in the ponds were moderate (1.13-6.77 g C/m super(3)/d), comprising high (31.27-139.82%) respiration values. Results emphasize the significance of the heterotrophic food chain in fish pond ecosystems and demonstrate the positive effects of simple measures like bottom raking on sediment-water interactions.
AN: 2423077
1213 of 1521
TI: Role of microorganisms in the association of trace elements with particles.
AU: Sunda,-W.G.
AF: Beaufort Lab., Southeast Fish. Cent., NMFS, NOAA, Beaufort, NC 28516, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 82
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: Recent experiments in metal ion buffer systems indicate that the ratio of intracellular to adsorbed extracellular Mn and Zn in photoplankton cells increases dramatically as their free ion concentrations are decreased toward levels thought to exist in seawater. This means that the relative proportion of adsorbed vs intracellular trace metals may change considerably between trace-metal-rich upwelled seawater and depleted oceanic seawater. Trace metal uptake by cells has been shown to be controlled by free ion concentrations of the metal in question as well as those of competing metal ions.
AN: 2420887
1214 of 1521
TI: A need to study interactive effects.
AU: Santschi,-P.H.
AF: EAWAG Swiss Fed. Inst. Technol., 8600 Dubendorf, Zurich, Switzerland
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 81
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: The development of surface chemical models has largely centered on interfacial reactions in well-defined systems. However, the extension of such models to problems of trace element and pollutant cycling has some problematical aspects arising from phYsical and biological "interactive" effects which are, as yet, non-deterministic. Better information on thermodynamic constants is necessary, but not sufficient to reach this goal. This means that surface chemistry has to deal more with interactive effects, such as those arising from trace metal-colloids-large particle interactions, or bacteria-phytoplankton-zooplankton-benthos foodchains, or organic C-trace metal interactions at particle surfaces under the influence of light.
AN: 2420871
1215 of 1521
TI: Important future research for environmental organic chemistry.
AU: Prahl,-F.G.
AF: Sch. Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 117
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: A major proportion of the organic matter synthesized by terrestrial and marine organisms does not survive long after the death of the biological source. Only a few percent is preserved in soils and aquatic sediments as a part of the geological record. On a molecular scale, however, the organic matter synthesized by organisms is not recycled uniformly. Careful study of residual organic molecular fossils preserved in sedimentary records has provided, and will continue to provide, valuable clues, refining our understanding of specific aspects of the C cycle.
AN: 2420028
1216 of 1521
TI: The influence of the sediment community on chemical transformations.
AU: Johnson,-K.S.
AF: Mar. Sci. Inst., Univ. California, Santa Barbara, CA 93106, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 115
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: Geochemical studies of chemical transformations near the sediment-water interface are often characterized by a lack of appreciation for the importance of biological processes. Many of the interesting processes that occur in this region are oxidation- reduction reactions driven by the microbial community. Yet, it is customary for geochemists to ignore the impact of this community on processes occurring within the sediments. The transport of chemicals often occurs due to irrigation of the sediments by macro-organisms. I believe that it is essential for our field to explicitly consider biological processes if we are to obtain accurate models of early diagenesis.
AN: 2420000
1217 of 1521
TI: Chemical and physical characterization of chromophoric organic material.
AU: Zika,-R.G.
AF: Univ. Miami, Rosenstiel Sch. Mar. and Atmos. Sci., Div. Mar. and Atmos. Chem., 4600 Richenbacker Causeway, Miami, FL 33149-1098, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 pp. P. 69
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: Our current understanding of the nature of photochemistry in the ocean indicates that a major portion of the reactions are initiated by the uncharacterized organic chromophores. This material has collectively been given names such as humic substance, Gelbstoffe, heteropolycondensate, or unknown chromophores (UCs). There are believed to be two primary origins for the UCs. One suggests that the material is mostly of riverine origin and exhibits quasi-conservative behavior in the ocean. The other view is that the UCs are formed in situ by autooxidative reactions of plankton-derived organic compounds.
AN: 2419999
1218 of 1521
TI: Coming to grips with the variability of surface water chemistry.
AU: Watson,-A.J.
AF: Mar. Biol. Assoc., Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 105
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: The chemistry of the ocean, particularly the surface layer, is continually changing. The most interesting substances are those which (like nutrients, CO sub(2) and O sub(2)) interact with marine life, and it is precisely those which are most variable. Satellite pictures show that productivity is often highly patchy, with phytoplankton blooms intricately convoluted by mesoscale eddies. Changes are so rapid that there seems little chance of getting a detailed global view of ocean chemistry if we are to be forever limited to taking data from occasional research cruises. One possible way that we might increase the amount of information available, especially about seasonal variations, would be to design chemical instrumentation for mounting on autonomous "data buoys" which could operate untended for months at a time.
AN: 2419993
1219 of 1521
TI: Questions for the modelling group.
AU: Whitfield,-M.; Turner,-D.
AF: Lab., Citadel Hill, Plymouth PL1 2PB, UK
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 pp. 95-96
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AN: 2419986
1220 of 1521
TI: Panel 2: The nature of reactions on marine particle surfaces.
AU: Honeyman,-B.O.; Adamson,-A.W.; Murray,-J.W.
AF: EAWAG, CH-8600, Dubendorf-Zurich, Switzerland
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 pp. 19-26
ST: APPL.-GEOCHEM. vol. 3, no. 1
LA: English
ER: M (Marine)
AB: The subject of this paper--the nature of the reactions at particle surfaces in seawater--was approached in four foci: (1) the distribution of U-Th series isotopes in the oceans and the evidence for scavenging; (2) the problem of organic coatings on surfaces and organic complexation of metals in seawater; (3) the role of metal uptake by marine organisms; and (4) the approaches and problems for modelling marine scavenging.
AN: 2419984
1221 of 1521
TI: Modelling the dynamics of ocean systems.
AU: Whitfield,-M.
AF: Lab., Citadel Hill, Plymouth PL1 2PB, UK
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 94
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: Substantial progress has been made in the development of baseline models for seawater using thermodynamic equilibrium concepts. The application of equilibrium models to marine systems has highlighted many important examples of chemical processes maintained far from equilibrium. The main challenges to the modeller now lie in assessing the dynamics of the system by providing (a) a proper assessment of kinetic controls on chemical processes and (b) an accurate representation of the interaction between biological processes and the chemistry of the oceans.
AN: 2419977
1222 of 1521
TI: Solute-particle and particle-particle reaction in seawater.
AU: Morel,-F.M.M.
AF: Dep. Civ. Eng., Build. 48-423, MIT, Cambridge, MA 02139, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 pp. P. 80
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: Further understanding of marine chemistry of trace elements depends on the elucidation of: (1) the nature of the chemical binding of elements and compounds to the surface of "dead" particles, the thermodynamics and kinetics of that binding, and the factors that control it, (2) the nature of biological surface reactions and uptake mechanisms, their specificity, reversibility and biological finality. (3) the relative role of physical, chemical (aggregation, disaggregation, settling) and biological processes in controlling the fate of marine particles, (4) the potential role of microparticles (say < 0.1 mu m) which are typically analyzed with the soluble phase but have physical-chemical properties of solids and participate in particle-interaction dynamics.
AN: 2419975
1223 of 1521
TI: Key problems in the organic chemistry of marine waters and sediments.
AU: Hedges,-J.I.
AF: Sch. Oceanogr., WB-10, Univ. Washington, Seattle, WA 98195, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 113
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: A variety of fundamental problems remain to be solved concerning processes that affect the origin and fates of organic substances in seawater and marine sediments. The processes themselves range from trace metal scavenging to photochemistry and C cycling. Although the myriad of organic substances involved in these processes can be daunting, this complexity represents a correspondingly large potential source of information that remains almost untapped.
AN: 2419971
1224 of 1521
TI: The nature and reactions of marine surfaces: Unresolved problems.
AU: Hunter,-K.A.
AF: Chem. Dep., Univ. Otago, P.O. Box 56, Dunedin, New Zealand
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 pp. P. 78
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: We have, as yet, very little information on the binding mechanisms responsible for reactive element scavenging by marine particles. We need techniques to study ion-binding by real surfaces under natural conditions in order to resolve this dilemma. The dynamics of the scavenging process are still poorly understood. The physical and electrical properties of small riverine particles are profoundly altered when they enter the sea, with demonstrable effects on particle size and colloidal state, e.g. Fe. What are the factors which determine the rate of particle interaction, and the size and morphology of aggregates? Surface organic films on particles look like being great solvents for organic pollutants. What is the importance of organic scavenging by particles?
AN: 2419952
1225 of 1521
TI: Origin, composition and fate of dissolved organic carbon.
AU: Repeta,-D.J.
AF: Dep. Chem., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 102
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: One of the most important outstanding problems in marine chemistry in which significant advances in our understanding can be achieved through the application of modern chemistry and chemical technology is the origin, composition, and fate of dissolved organic C. Organic C dissolved in seawater constitutes one of the largest potentially "reactive" reservoirs of C on the planet (10 super(18) g C). At present there are no known sinks for dissolved organic C, although photochemical oxidation has been suggested.
AN: 2419951
1226 of 1521
TI: Problems in chemical oceanography and marine chemistry.
AU: Dyrssen,-D.
AF: Dep. Anal. and Mar. Chem., Univ. Goteborg, Goteborg S-412 96, Sweden
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 101
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AN: 2419944
1227 of 1521
TI: The nature of reactions on particle surfaces in seawater.
AU: Fisher,-N.S.
AF: Oceanogr. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 pp. P. 76
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: One area regarding metal-particle interactions which has received comparatively little study is the degree to which metals, once associated with biogenic particulates, are retained by these particles as they sink through the water column. To what extent can we consider the association of different metals with biogenic debris irreversible? What are the rates of release of different metals from particulate matter, and how are these rates influenced by environmental factors? It is really self-evident that this information would have direct bearing on our understanding of the particle-mediated flux of metals in marine systems.
AN: 2419924
1228 of 1521
TI: What do we need to know about kinetics in marine chemistry?.
AU: Dickson,-A.G.
AF: Mar. Phys. Lab., S-002, Scripps Inst. Oceanogr., La Jolla, CA 92093-0902, USA
CO: CHEMRAWN IV. Modern Chem. and Chem. Technol. Appl. to the Ocean and Its Resources, Keystone, CO (USA), 4-9 Oct 1987
SO: CHEMRAWN-IV.-MODERN-CHEMISTRY-AND-CHEMICAL-TECHNOLOGY-APPLIED-TO-THE-OCEAN-AND-ITS-RESOURCES.-PROCEEDINGS-OF-AN-INTERNATIONAL-CONFERENCE-AND-WORKSHOP-SPONSORED-BY-THE-INTERNATIONAL-UNION-OF-PURE-AND-APPLIED-CHEMISTRY,-HELD-AT-KEYSTONE,-COLORADO,-U.S.A.,-4-9-OCTOBER-1987. Goldberg,-E.D.-ed. 1988. vol. 3, no. 1 p. 88
ST: APPL.-GEOCHEM. vol. 3, no. 1
NT: Summary only.
LA: English
ER: M (Marine)
AB: The oceans comprise a multifaceted chemical environment. A wide variety of chemical, physical, and biological processes occur, each with its own characteristic scales of time and space. It is the interaction between these various processes that fascinates the marine chemist. How should one study such a varied and dynamic system? The identification and measurement of the parameters which control the kinetics of such processes will be a goal of marine chemists for some time.
AN: 2419922
1229 of 1521
TI: CHEMRAWN IV. Modern Chemistry and Chemical Technology Applied to the Ocean and Its Resources. Proceedings of an International Conference and Workshop Sponsored by the International Union of Pure and Applied Chemistry, held at Keystone, Colorado, U.S.A., 4-9 October 1987 (CHEMRAWN IV: An overview).
AU: Goldberg,-E.D.-(ed.); Hitchon,-B.
AF: Appl. Geochem.
CO: CHEMRAWN IV: Modern Chemistry and Chemical Technology Applied to the Ocean and its Resources. Int. Conf. and Workshop, Keystone, CO (USA), 4-9 Oct 1987
SO: APPL.-GEOCHEM. 1988. vol. 3, no. 1, 140 pp
LA: English
ER: M (Marine)
AB: The International Union of Pure and Applied Chemistry (IUPAC), of which the International Association of Geochemistry and Cosmochemistry (IAGC) is an Associated Organization, sponsors a series of conferences with the general title CHEMRAWN, which stands for CHEMical Research Applied to World Needs. Each conference is important, in its own right, to the future well being of mankind. None, however, has the potential global impact on the very existence of the human race as does CHEMRAWN IV, the subject of this issue of Applied Geochemistry. Global change has been the subject of much research in the past decade. It was the recognition of the need to link experts in ocean geochemistry and chemistry that led to CHEMRAWN IV. The conference was structured in a series of five problem areas, each comprising short statements by geochemists and chemists summarizing their perceived needs for research and posing questions for deliberation by panels set up to address the problem areas.
AN: 2419920
1230 of 1521
TI: Nutrient release rates from the sediments of Saginaw Bay, Lake Huron.
AU: Ullman,-W.J.; Aller,-R.C.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: HYDROBIOLOGIA. 1989. vol. 171, no. 2, pp. 127-140
LA: English
ER: F (Freshwater)
AB: Direct measurements of net production rates and pore water profiles of solutes in the fine-grained sediments of Saginaw Bay, imply corresponding steady-state fluxes to the overlying water of 1.1-1.3 (I), 450-1010 (NH sub(4) super(+)), 1250-2650 (Si(OH) sub(4)), 3000-3400 (Ca super(2+)), 440-1330 (Mg super(2+)), 1.5-728 (Fe super(2+)), and 179-281 (Mn super(2+)) mu moles/m super(2)/day and 11.0-11.8 (alkalinity) meq/m super(2)/day at 17.5 degree C. Silica production rates in sediments apparently follow first order kinetics with a rate coefficient of similar to 0.09/day and a steady-state silica concentration of 1.2 mM at 23.5 degree C. The remaining solutes follow kinetics approximately independent of solute concentration over the range of concentrations observed. Solute production rates are consistent with observed solute profiles only if lateral diffusion gradients are maintained in the sediments by the burrowing and irrigation activity of benthic organisms such as Chironomous). Extrapolated silica fluxes from Lake Huron sediments balance the estimated biogenic silica flux to the sediments.
AN: 2410786
1231 of 1521
TI: New production at the VERTEX time-series site.
AU: Knauer,-G.A.; Redalje,-D.G.; Harrison,-W.G.; Karl,-D.M.
AF: Univ. South. Mississippi Cent. Mar. Sci., John C. Stennis Space Cent., SSC, MS 39529, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1990. vol. 37, no. 7A, pp. 1121-1134
LA: English
ER: M (Marine)
AB: Particulate organic carbon and nitrogen fluxes measured with free-floating sediment traps deployed six times over an 18-month period were combined with super(14)C primary production and super(15)N uptake measurements in order to obtain annual estimates of new production (NP) and associated f-ratios at the VERTEX time-series site. The site, located in the northeast Pacific Ocean at 33 degree N, 139 degree W, was occupied at trimonthly intervals to conduct water column studies and to recover/redeploy the sediment traps. The upper 250 m of the VERTEX site exhibited considerable variability in some biological properties over seasonal time scales. The f-ratio appeared to be inversely related to primary production, with lowest estimates obtained during the period of highest productivity. Values of annual NP derived from various estimates were remarkably similar ranging from 13-17 g C/m super(2)/y. The average annual f-ratio ranged from 0.11 to 0.14.
AN: 2408861
1232 of 1521
TI: Anomalous nutrient distribution in the equatorial Pacific in April 1988: Evidence for rapid biological uptake.
AU: Bender,-M.L.; McPhaden,-M.J.
AF: Grad. Sch. Oceanogr., Univ. Rhode Island, Kingston, RI 02881, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1990. vol. 37, no. 7A, pp. 1075-1084
LA: English
ER: M (Marine)
AB: Nutrients in the central equatorial Pacific are normally enriched at the Equator, with concentrations gradually falling to the north and south. This pattern reflects input by equatorial upwelling, with slow removal as waters flow poleward. In April 1988, we observed minima in SiO sub(2) and NO sub(3-) + NO sub(2-) concentrations near the Equator. (SiO sub(2)) in particular dropped to minima at 2.5 degree N and 1-2.5 degree S, rose to maxima at 3 degree N and 3-6 degree S, then fell off in the normal pattern. Such minima are unusual features not clearly evident in data from other equatorial Pacific transects. A period of anomalous hydrographic conditions preceded the time of our chemical observations. Between February 1988 and April 1988, the anomalously warm conditions which characterized the equatorial Pacific during the 1986-1987 El Nino/Southern Oscillation event ended, and the thermocline shoaled sharply. The authors speculate that the anomalous nutrient distributions we observed in April are related to the regional hydrography of the preceding months. Physical forcing may have triggered rapid biological SiO sub(2) and NO sub(3-) removal, producing the anomalous nutrient distribution we observed.
AN: 2408851
1233 of 1521
TI: Phosphorus metabolism in coral reef communities: Dynamics in the water column.
AU: Sorokin,-Yu.I.
AF: Oceanol. Dep., Gelendzhik-7, Krasnodar District 353470, USSR
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1990. vol. 41, no. 6, pp. 775-783
LA: English
ER: M (Marine)
AB: Phosphorus dynamics were studied in the coral reef waters of Heron and Wistari Reefs in the Capricornia group, Great Barrier Reef, Australia. All studies were made during August-October 1986. Labelled phosphate (PO sub(4)- super(33)P) was used to measure total uptake as well as uptake by bacterioplankton. Rates of total PO sub(4)-P uptake by microplankton varied between 20 and 120 ng P/L/h at water temperatures of 20-24 degree C. The daily (24 h) uptake rate of PO sub(4)-P was 0 multiplied by 5-3 multiplied by 0 mu g/L. The ambient PO sub(4)-P content of water over the reefs was low (0 multiplied by 03-0 multiplied by 3 mu mol/L, or 1-10 mu g P/L). Turnover time of PO sub(4)-P in the water column of these reef areas is therefore very short, being in the range of 2-8 days, even when its possible net consumption by bottom biota is ignored. Bacterioplankton, not phytoplankton, was found to be the major consumer of inorganic phosphorus in the waters. The results of these estimations are discussed in terms of the importance of active phosphorus dynamics in the water column to the nutrient budget of the coral reef ecosystem.
AN: 2407357
1234 of 1521
TI: Fate of added super(15)N labelled nitrogen in a Sagittaria lancifolia L. Gulf Coast marsh.
AU: DeLaune,-R.D.; Lindau,-C.W.
AF: Lab. Wetland Soils and Sediments, Louisiana State Univ., Baton Rouge, LA 70803-7511, USA
SO: J.-FRESHWAT.-ECOL. 1990. vol. 5, no. 3, pp. 265-268
LA: English
ER: F (Freshwater)
AB: Response of Sagittaria lancifolia L. to added super(15)N labelled nitrogen was studied in a Louisiana Gulf Coast freshwater marsh. The amount of the added labelled NH sub(4) super(+)-N remaining in the soil or plant tissue was determined several times during the growing season. Above-ground biomass increased by approximately 100 percent following the addition of 10 g NH sub(4) super(+)-N/m super(2). There was no significant nitrogen loss from the soil during the growing season after the labelled inorganic nitrogen was apparently immobilized into the soil organic nitrogen pool.
AN: 2406029
1235 of 1521
TI: A comparison of detritus processing between permanent and intermittent headwater streams.
AU: Richardson,-W.B.
AF: Savannah River Ecol. Lab., Drawer E, Aiken, SC 29801, USA
SO: J.-FRESHWAT.-ECOL. 1990. vol. 5, no. 3, pp. 341-357
LA: English
ER: F (Freshwater)
AB: The pattern of leaf pack decomposition and density and biomass of the associated invertebrate detritivore community of an intermittent and a perennially flowing headwater stream were compared in autumn and spring. Leaf packs of high (Alnus rugosa ) and low (Fraxinus americana ) nitrogen content were used. The intermittent stream had a depauparate shredder fauna and was numerically dominated by collectors. Lack of shredding detritivores, combined with decreased duration of submersion, resulted in reduced potential for processing of particulate carbon relative to the permanently flowing stream.
AN: 2405741
1236 of 1521
TI: Aragonite production by pteropod molluscs in the subarctic Pacific.
AU: Fabry,-V.J.
AF: Chem. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1989. vol. 36, no. 11A, pp. 1735-1751
LA: English
ER: M (Marine)
AB: Daily aragonite production of thecosomatous pteropods in the subarctic Pacific was estimated using the instantaneous growth rate and size-frequency methods. At Ocean Sta. PAPA during July 1985, samples for production estimates of two pteropod species, Clio pyramidata and Limacina helicina , were collected in plankton tows using nets of different mesh sizes (303, 150 and 73 mu m) to include all size classes of pteropods. Estimates of calcium carbonate biomass of C. pyramidata and L. helicina were 67 and 155 mg CaCO sub(3)/m super(2), respectively. Based on a model of annual production, pteropod aragonite accounts for 4-13% of the estimated total CaCO sub(3) production of 12-20 g CaCO sub(3)/m super(2)/y. Results of the model suggest that coccolithophorids are the major producers of CaCO sub(3) at Sta. PAPA, contributing 59-77% of the estimated total CaCO sub(3) production.
AN: 2397812
1237 of 1521
TI: Flux of transuranium nuclides and chlorinated hydrocarbons in the northwestern Mediterranean.
AU: Fowler,-S.W.; Ballestra,-S.; Villeneuve,-J.-P.
AF: IAEA, Int. Lab. Mar. Radioact., 19 Ave. Castellans, MC 98000, Monaco
SO: CONT.-SHELF-RES. 1990. vol. 10, no. 9-11 Sep, pp. 1005-1023
LA: English
ER: M (Marine)
AB: The transuranium nuclides, plutonium and americium, and selected chlorinated hydrocarbon compounds have been measured in sediment trap samples, bottom sediments and waters. These measurements have been used to quantify vertical fluxes and elucidate particulate biogeochemical cycles, of these man-made contaminants in the northwestern Mediterranean. Sediment trap experiments in the Gulf of Lions (Lacaze-Duthiers Canyon) have shown that transuranic fluxes are considerably higher in the Gulf of Lions, than those which have been reported for the northeast Pacific; principally this is due to the relatively high mass fluxes in this region of the Mediterranean. Water, surface sediment and sediment trap data indicate that super(241)Am is being transported downward (via particle settling) more rapidly than super(239-240)Pu. From direct flux measurement, residence times for super(239-240)Pu and super(241)Am in the upper 300 m were computed to be 2.5 and 0.14 years, respectively. Comparison of super(239-240)Pu concentrations in the water column in 1986, with similar measurements made 5-11 years earlier suggests that fallout input to the Mediterranean has decreased by nearly a factor of 2 during the period 1975-1986.
AN: 2397465
1238 of 1521
TI: super(210)Po, super(210)Pb in sediment trap particles on a Mediterranean continental margin.
AU: Heussner,-S.; Cherry,-R.D.; Heyraud,-M.
AF: Lab. Sedimentol. Geochim. Mar., CNRS URA 715, Univ. Perignan, 66025 Perpignan, France
SO: CONT.-SHELF-RES. 1990. vol. 10, no. 9-11, pp. 989-1004
LA: English
ER: M (Marine)
AB: Concentrations of the natural radionuclides super(210)Po and super(210)Pb were measured in particulate matter collected in sediment traps, deployed in the Gulf of Lions during the first phase of the ECOMARGE programme (between July 1985 and April 1986). The data obtained are unexceptional in terms of the absolute concentrations measured, but show interesting features in the super(210)Po/ super(210)Pb activity ratios. These are high (about 6) in samples collected in summer at 50 m depth, they are above unity in all except one of the 50 and 100 m depth samples, and are less than unity in most of the deeper (300 and 600 m) samples. There is a clear tendency for super(210)Po to covary with organic matter and biogenic silica; likewise, for super(210)Pb to covary with carbonates and refractory silicates. Particulate matter fluxes and nuclide fluxes into the deep traps were very high in winter. The utility of the super(210)Po/ super(210)Pb activity ratios, as indicators of the origin of these fluxes, is highlighted.
AN: 2397390
1239 of 1521
TI: Seasonality and composition of particulate fluxes during ECOMARGE-I, western Gulf of Lions.
AU: Monaco,-A.; Courp,-T.; Heussner,-S.; Carbonne,-J.; Fowler,-S.W.; Deniaux,-B.
AF: Lab. Sedimentol. Geochim. Mar., Univ. Perpignan, Ave. Villeneuve, 66025 Perpignan Cedex, France
SO: CONT.-SHELF-RES. 1990. vol. 10, no. 9-11, pp. 959-987
LA: English
ER: M (Marine)
AB: As part of the ECOMARGE program (ECOsystemes de MARGE continentale), sequential sediment traps were deployed on the continental margin of the Gulf of Lions, in the northwestern Mediterranean Sea. Two sites located in the southwestern part of this region were selected for the first phase of the experiment: inner shelf (bottom depth: 27 m) and continental slope (Lacaze-Duthiers Canyon, bottom depth: 650 m). Total mass, organic matter, opal, carbonate and siliciclastic residue fluxes were measured biweekly at 50, 100, 300 and 600 m in the upper part of the Lacaze-Duthiers Canyon (from July 1985 to April 1986) and for longer periods (2 weeks to 2 months) at 10 and 25 m on the shelf (from May 1985 to June 1986). Mass fluxes increased generally with depth, reaching values as high as 20,000 mg m super(-2)/d in the 600 m slope (canyon) trap; this indicated lateral transport of biogenic and abiogenic particulate matter, from local (adjacent shelf and upper slope waters) and distant origin (Rhone River).
AN: 2397344
1240 of 1521
TI: Particle fluxes and ecosystem response on a continental margin: The 1985-1988 Mediterranean ECOMARGE experiment.
AU: Monaco,-A.; Biscaye,-P.; Soyer,-J.; Pocklington,-R.; Heussner,-S.
AF: Lab. Sedimentol. Geochim. Mar., Univ. Perpignan, Ave. Villeneuve, 66025 Perpignan, France
SO: CONT.-SHELF-RES. 1990. vol. 10, no. 9-11, pp. 809-839
LA: English
ER: M (Marine)
AB: The first experiment of the ECOMARGE programme (ECOsystemes de MARGE continentale) was initiated in 1983-1984, in the Gulf of Lions (northwestern Mediterranean Sea). The objectives of the ECOMARGE--I experiment were: to quantify the transfer of particulate matter, in general, and of organic carbon, in particular, from its introduction to and formation in the waters of the continental shelf--to its consumption or sedimentation on the shelf or its transfer to the slope and deep sea; and to understand the processes involved in that transfer, consumption and sedimentation together with their variability in space and time. The results of that experiment, from 1983 to 1988, are presented in this Special Issue. The highlights of the results are summarised in this paper.
AN: 2396907
1241 of 1521
TI: Dissolved titanium in the open ocean.
AU: Orians,-K.J.; Boyle,-E.A.; Bruland,-K.W.
AF: Dep. Oceanogr., Univ. British Columbia, Vancouver, B.C. V6T 1W5, Canada
SO: NATURE. 1990. vol. 348, no. 6299, pp. 322-325
LA: English
ER: M (Marine)
AB: Here we present measurements of titanium profiles in the open ocean. Dissolved titanium is found to be a reactive short-residence-time element, with a unique and highly non-uniform spatial distribution. Dissolved titanium is depleted in surface waters and enriched in deep waters, with a range of more than two orders of magnitude, and there are several indications that it is scavenged (removed by biotic or abiotic processes). This unusual oceanic distribution makes titanium potentially useful as a new tracer of chemical transport processes in deep waters.
AN: 2396826
1242 of 1521
TI: Fluxes and budget of organic matter in the benthic boundary layer over the northwestern Mediterranean margin.
AU: Buscail,-R.; Pocklington,-R.; Daumas,-R.; Guidi,-L.
AF: Lab. Sedimentol. Geochim. Mar., CNRS UA 715, Univ. Perpignan, Ave. de Villeneuve, 66025 Perpignan Cedex, France
SO: CONT.-SHELF-RES. 1990. vol. 10, no. 9-11, pp. 1089-1122
LA: English
ER: M (Marine)
AB: Sediment traps were deployed at depths of 26 and 645 m at 2 stations on the continental margin of the Gulf of Lions (northwestern Mediterranean). During the same period, surficial sediments were sampled by box corer. The material collected by bottom sediment traps and in corresponding surface sediments was analysed for total organic carbon, hydrolysable organic carbon, nitrogen, sugars, amino acids and lignin-derived compounds. Seasonal variations in organic inputs and the difference between particles from bottom layers and sediment were compared.
AN: 2396733
1243 of 1521
TI: Tracers and constituents indicating the nature of organic fluxes, their origin and the effect of environmental conditions.
AU: Gadel,-F.; Puigbo,-A.; Alcaniz,-J.M.; Charriere,-B.; Serve,-L.
AF: Lab. Sedimentol. Geochim, Mar., Ave. Villenueve, Univ. Perpignan, France
SO: CONT.-SHELF-RES. 1990. vol. 10, no. 9-11, pp. 1039-1062
LA: English
ER: M (Marine); B (Brackish)
AB: The nature of particulate organic matter was studied in suspended material sampled by bottles, particles collected by sediment traps and deposits from deltaic and open sea ecosystems of the northwestern Mediterranean. Elemental analyses were combined with pyrolysis-gas chromatography-mass spectrometry and with analysis of individual compounds such as phenols separated by high-performance liquid chromatography. Two marine prodeltas were compared: organic matter was more degraded in suspended material and sediments collected in the submarine delta of the Rhone River. Organic material originating from the river was transported further offshore, as indicated by a higher content of aromatic hydrocarbons and phenols. In the southwestern part of the Gulf of Lions, the prodelta reflected the influence of local rivers, with lower discharges.
AN: 2396685
1244 of 1521
TI: Contribution of the Rhone River to organic carbon inputs to the northwestern Mediterranean Sea.
AU: Cauwet,-G.; Gadel,-F.; Souza-Sierra,-M.M.-de; Donard,-O.; Ewald,-M.
AF: Lab. Sedimentol. Geochim. Mar., URA CNRS 715, Univ. Perpignan, France
SO: CONT.-SHELF-RES. 1990. vol. 10, no. 911, pp. 1025-1037
LA: English
ER: M (Marine)
AB: Particulate and dissolved organic carbon were determined in coastal waters of the Gulf of Lions, during several cruises from 1986. The input by the Rhone River and its seasonal variability are studied and new data are given concerning the contribution to the Mediterranean Sea. Fluorescence measurements show the limited influences on the open sea of surface particulate matter, but suggest a bottom transport during which diagenetic evolution can occur. The remobilization of dissolved organic matter is also stressed.
AN: 2396684
1245 of 1521
TI: Release of extracellular organic carbon from phytoplankton: An experimental approach.
AU: Riemann,-B.
AF: Int. Agency 14C Determination, Water Qual. Inst., Agern Alle 11, DK-2970 Hoersholm, Denmark
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Straskrabova,-V.-ed. 1990. no. 34 p. 35
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Traditionally, measurements of extracellular release of organic carbon (EOC) from phytoplankton is measured by means of 14C-technique. It is proposed to utilize growth of aquatic bacteria as markers of exudation from phytoplankton in laboratory experiments in which phytoplankton is the only carbon source for the bacteria. Batch cultures of natural populations of freshwater bacteria were diluted in a mixture of inorganic medium + EOC from cultures of exponentially growing freshwater phytoplankton. The algae were grown in inorganic medium. The bacteria were mixed with various concentrations of algae, and bacterial production and increase in cell number were measured during periods of 72 h and compared with algal biomass, cell, surface and cell volume. Bacterial production always covaried with algal biomass suggesting a close coupling between algal biomass and release of EOC. Moreover, in most experiments, algal photosynthesis was positively correlated to bacterial production.
AN: 2387559
1246 of 1521
TI: Phytoplankton exudation: Income tax or property tax?.
AU: Bjoernsen,-P.K.
AF: Mar. Biol. Lab., Univ. Copenhagen, Strandpromenaden 5, DK-3000 Helsingoer, Denmark
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Straskrabova,-V.-ed. 1990. no. 34 p 33
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: A considerable proportion of phytoplankton primary production is exudated as dissolved organic matter and rapidly utilised by bacterioplankton. The exudation is traditionally interpreted as an active release of photosynthesis in periods of nutrient stress when carbon fixation is faster than biomass build-up. This "overflow" hypothesis is criticized in an ecological and physiological context. An alternative hypothesis is presented, that a major part of the exudation can be explained as a passive diffusion of low molecular weight organic compounds through the algal cell membrane. This "leakage" hypothesis is supported by a theoretical calculation from data on lipid bilayer membrane permeability to organic molecules and by literature data from field observations and laboratory experiments. The ecological and methodological implications of the two hypotheses are discussed.
AN: 2387533
1247 of 1521
TI: Microbial interactions during decomposition of Phragmites litter.
AU: Gunatilaka,-A.; Mendez,-M.C.; Herndl,-G.
AF: Inst. Zool., Univ. Vienna, Althanstr. 14, A-1090 Vienna, Austria
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Straskrabova,-V.-ed. 1990. no. 34 p. 127
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: P. australis is the most important emergent macrophyte in the littoral zone of Neusiedlersee, contributing to > 99% of the vegetation cover (178 km super(2)), serving as the major source of organic detritus input into the lake ecosystem. Information available on the role of microbes in the decomposition of Phragmites litter is scarce. The initial phase of the microbial succession was followed in laboratory incubation experiments. Free-living bacterial biomass (as determined by AODC) increased about by one order of magnitude within the first day. Thereafter, nanoflagellates entered exponential growth resulting in a decline in the free-living bacterial population. While the free-living microbial (heterotrophic bacteria + nanoflagellates) community exhibited typical prey-predator oscillations in abundance, the attached microbial community showed a more complex colonization pattern. The initial colonizers of Phragmites litter were coccoid bacteria with a mean volume similar to that of the free-living counterpart.
AN: 2387024
1248 of 1521
TI: Assimilation of free monosaccharides and amino acids relative to bacterial production in eutrophic lake water.
AU: Joergensen,-N.O.G.
AF: Inst. Microbiol., R. Vet. and Agric. Univ., Rolighedsvej 21, DK-1958 Frederiksberg C, Denmark
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Straskrabova,-V.-ed. 1990. no. 34 pp. 99-110
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
LA: English
ER: F (Freshwater)
AB: Bacterial assimilation of dissolved free glucose, fructose and amino acids was studied in two eutrophic lakes and in a laboratory experiment. Assimilation rates were related to the actual bacterial production. Natural concentrations of free fructose in the lakes were measured combining separation by HPLC with a post-column colour reaction of the saccharides. Free amino acids were quantified as fluorescent derivatives. Concentrations of free glucose, fructose and amino acids in the lakes were 33-95 nM, 7-55 nM and 6-34 nM, respectively. Assimilation (respiration + incorporation) of the organic compounds on the average sustained 6.7, 11 and 61% of the bacterial carbon requirement. Glucose was the predominant compound assimilated, followed by either fructose or amino acids. A large production of both monosaccharides and amino acids occurred during the experiments. Generally the bacterial production varied independently of concentrations and assimilation rates of the tested organic compounds.
AN: 2386946
1249 of 1521
TI: Measurement of exoenzymatic activity in streambed sediments using methylumbelliferyl-substrates.
AU: Marxsen,-J.
AF: Limnol. Flussstn., Max-Planck-Inst. Limnol., Postfach 260, D-6407 Schlitz, FRG
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Witzel,-K.-P.;Straskrabova,-V.-ed. 1990. no. 34 pp. 21-28
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
LA: English
ER: F (Freshwater)
AB: 4-Methylumbelliferyl-substrates were used to measure the activity of extracellular beta -D-glucosidase and phosphatase in small central European streams. The substrates could be used for stream water, sandy sediments, and coarser artificial substrata. Although beta -D-glucosidase activity per unit surface area was about ten times higher in coarse particulate sediments than in sandy sediments, maximum activity per unit volume was observed in sandy sediments. This means that for the stream as a whole, the greater proportion of the exoenzymatic cleavage activity occurs in the sandy streambed deposits.
AN: 2386935
1250 of 1521
TI: Microorganisms in marine sediments: Considerations concerning activity measurements.
AU: Meyer-Reil,-L.-A.
AF: Inst. Oceanol., Univ. Kiel, Duesternbrooker Weg 20, D-2300 Kiel, FRG
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Straskrabova,-V.-ed. 1990. no. 34 pp. 1-6
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
LA: English
ER: M (Marine)
AB: The measurement of microbial activities in marine sediments suffers from both an insufficient consideration and knowledge of benthic microbial life characteristics and an uncritical application of methods to the sediment environment. This paper illustrates that sediments are highly complex environments, the activity of which is based on the extracellular enzymatic decomposition of particulate organic material. The information available calls for the use of undisturbed sediments in activity measurements and a critical application of methods. Furthermore, new approaches are needed to follow microbial activity responses in the sediment environment.
AN: 2386931
1251 of 1521
TI: Production and utilization of organic matter by microplankton in an eutrophic lake.
AU: Siuda,-W.; Wcislo,-R.
AF: Dep. Environ. Microbiol., Univ. Warsaw, Karowa 18, 00-325 Warsaw, Poland
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Straskrabova,-V.-ed. 1990. no. 34 pp. 67-73
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
LA: English
ER: F (Freshwater)
AB: Production and utilization of photosynthetic organic matter were studied in the pelagic zone of highly eutrophicated Lake Mikolajskie, Mazurian Lake District, Poland. similar to 97% of the total fixed super(14)CO sub(3) (TFC) was incorporated photosynthetically by algal cells, and 3% was fixed by microplankton in darkness. In the course of photosynthesis similar to 20% of TFC was released into the water, similar to 10% and 70% of TFC was respired and remained in microplankton particulate fraction (POC), respectively. The chemical composition of POC produced was strongly dependent upon light conditions during photosynthesis. Radiocarbon was mainly incorporated into water soluble low molecular weight compounds (LMWC) and polysaccharide fractions. The increased contribution of proteins and lipids to POC was found when algal photosynthesis was light limited. Released organic carbon and the LMWC fraction of POC were preferentially utilized by aquatic bacteria. Supplementation of water samples with LMWC stimulated the bacterial growth rates and production.
AN: 2386871
1252 of 1521
TI: A numerical model of phosphorus exchange between the sediments and the near-bottom water in a lake.
AU: Mitraszewski,-P.; Uchmanski,-J.
AF: Lab. Med. Phys., Inst. Exp. Phys., Warsaw Univ., Hoza 69, 00-681 Warsaw, Poland
SO: EKOL.-POL. 1989. vol. 36, no. 3-4, pp. 317-346
LA: English
ER: F (Freshwater)
AB: A model describing phosphorus exchange between the sediments and the near-bottom water in a lake has been presented. The effect has been considered of bottom animals (Chironomidae and Tubificidae), through their respiratory activity, on this process. It has been found that: (a) under anaerobic conditions the model is more sensitive to parameter variation, (b) estimated by sensitivity analysis of the model, the proportion of phosphorus released by benthonic organisms comes up to 30%, (c) the role of Chironomidae larvae in phosphorus release from sediments is greater than that of Tubificidae.
AN: 2386867
1253 of 1521
TI: Production and respiration of free-living bacterioplankton in a eutrophic lake.
AU: Bell,-R.T.
AF: Inst. Limnol., Uppsala Univ., S-75122 Uppsala, Sweden
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Straskrabova,-V.-ed. 1990. no. 34 p. 171
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Although measurements of heterotrophic bacterial production have proliferated during the past decade, estimates of the total carbon flux (i.e. - including respiration) through the bacterioplankton are fewer. Bacterioplankton production (thymidine method), total plankton respiration and bacterioplankton (< 1- mu m size fraction) respiration (ETS method calibrated against the Winkler oxygen method; R:ETS = 0.9 for bacteria and 0.26 for total plankton) were measured from May to September, 1987 in hyper-eutrophic Lake Vallentunasjoen, Sweden. Bacterial production ranged from 1-6 mu g C/l/h, and bacterial respiration from ca 1.5 to 11 mu g C/l/h. The bacterial carbon conversion efficiency ranged from 10-50%, averaging 32% and was significantly correlated with the bacterial growth rate. Respiration by the < 1- mu m size fraction was from 20-70% of total plankton respiration.
AN: 2386753
1254 of 1521
TI: Group report. How do organic acids interact with solutes, surfaces, and organisms?.
CO: Dahlem Workshop on Organic Acids in Aquatic Ecosystems, Berlin (FRG), 7-12 May 1989
SO: ORGANIC-ACIDS-IN-AQUATIC-ECOSYSTEMS.-REPORT-OF-THE-DAHLEM-WORKSHOP-ON-ORGANIC-ACIDS-IN-AQUATIC-ECOSYSTEMS.-BERLIN-1989,-MAY-7-12. Perdue,-E.M.;Gjessing,-E.T.-eds. 1990. pp. 223-243
ST: LIFE-SCI.-RES.-REP.
LA: English
AB: An examination is made of interactions that influence the temporal and spatial variability of organic acids in aquatic ecosystems. Organic acids can interact with different species of organisms, with other solutes such as cations and metals and with particulate surfaces. Those interactions relevant to water quality, such as eutrophication, acidification and drinking water treatment are discussed in particular.
AN: 2386721
1255 of 1521
TI: Compositional indicators of organic acid sources and reactions in natural environments.
AU: Hedges,-J.
AF: Sch. Oceanogr., WB-10, Univ. Washington, Seattle, WA 98195, USA
CO: Dahlem Workshop on Organic Acids in Aquatic Ecosystems, Berlin (FRG), 7-12 May 1989
SO: ORGANIC-ACIDS-IN-AQUATIC-ECOSYSTEMS.-REPORT-OF-THE-DAHLEM-WORKSHOP-ON-ORGANIC-ACIDS-IN-AQUATIC-ECOSYSTEMS.-BERLIN-1989,-MAY-7-12. Perdue,-E.M.;Gjessing,-E.T.-eds. 1990. pp. 43-63
ST: LIFE-SCI.-RES.-REP.
LA: English
AB: Both bulk chemical measurements (e.g., elemental, isotopic, and spectral analyses) and molecular tracers (biomarkers) can be used to determine the sources and reaction histories of organic acids in natural environments. This paper reviews selected characterization methods of these 2 types and critically evaluates their strengths and weaknesses. Finally, research directions are suggested that might lead to more accurate and sensitive procedures for determining the sources and pathways of organic acids in natural environments.
AN: 2386675
1256 of 1521
TI: Marine amorphous aggregates (marine snow) as a model system of the "microbial loop".
AU: Herndl,-G.J.
AF: Inst. Zool., Univ. Vienna, Althanstr. 14, A-1090 Vienna, Austria
CO: 4. Int. Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Ceske Budejovice (Czechoslovakia), 1988
SO: PROCEEDINGS-OF-THE-FOURTH-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Straskrabova,-V.-ed. 1990. no. 34 p. 265
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 34
NT: Summary only.
LA: English
ER: M (Marine)
AB: In the Northern Adriatic Sea, marine snow dry mass varied between 3.4-9.1 mg/l; mean total carbohydrate (TCHO) content of marine snow ranges from 200-800 mu g TCHO/ml (marine snow). TCHO in marine snow was found to be enriched by a factor (EF) of 304 as compared to the surrounding water (x@u- = 0.82 mu g TCHO/ml). The microhererotrophic community in marine snow was dominated by bacteria, choanoflagellates and monads. (EF: 1.3-290). O sub(2)-flux measurements revealed that 90% of the pelagic gross primary production and similar to 70% of the mineralization activity is bound to marine snow during summer. Batch cultures with marine snow were designed to investigate the influence of marine snow on the free-living microbial community. The degree of the development of the microheterotrophic food chain was quantified using the ratio (nanoflagellate biomass/bacterial biomass) x 100. Ratios of > 100 were maintained most of the time, suggesting that additional food sources other than free-living bacteria were exploited by the nanoflagellates population.
AN: 2386600
1257 of 1521
TI: Simulation model of phosphorus cycling in the epilimnion of a eutrophic lake.
AU: Uchmanski,-J.
AF: Inst. Paleobiol., Pol. Acad. Sci., Al. Zwirki i Wigury 93, 02-089 Warsaw, Poland
SO: EKOL.-POL. 1989. vol. 36, no. 3-4, pp. 347-386
LA: English
ER: F (Freshwater)
AB: The model describes time-related changes in six variables: concentration of dissolved orthophosphate phosphorus P-PO sub(4), phytoplankton, bacteria, detritus, non-predatory zooplankton, and predatory zooplankton in the epilimnion of Lake Glebokie, Poland. The stability of the model was analysed, and it has been found that the variables show damped oscillations around equilibrium points. Results of numerical experiments are presented, simulating a cessation of fish farming in the lake, changes in the level and timing of phosphorus inflow to the epilimnion from deeper layers of the lake, and changes in temperature and light conditions. The results show that the inflow of phosphorus from deeper layers largely influences the values of the model variables.
AN: 2383085
1258 of 1521
TI: Methods for improving the efficiency of calibration of a model of phosphorus cycling in a lake ecosystem.
AU: Loga,-M.
AF: Inst. Environ. Eng., Warsaw Tech. Univ., Nowowiejska 20, 00-653 Warsaw, Poland
SO: EKOL.-POL. 1989. vol. 36, no. 3-4, pp. 387-406
LA: English
ER: F (Freshwater)
AB: The author describes methods for improving the efficiency of calibration of a model of phosphorus cycling in a lake ecosystem. The traditional trial and error method is not an efficient tool for estimating the parameters of ecological models. The degree of complication of a typical ecological model also makes it impossible to use available formal algorithms. Two techniques can, however, be suggested which considerably improve the process of parameter estimation. One of them is the method of step by step merging subsequent state equations, and the other that of aiding the estimation process with sensitivity analysis.
AN: 2382864
1259 of 1521
TI: Alkylmercury species in the Equatorial Pacific.
AU: Mason,-R.P.; Fitzgerald,-W.F.
AF: Dep. Mar. Sci., Univ. Connecticut, Avery Point, Groton, CT 06340, USA
SO: NATURE. 1990. vol. 347, no. 6292, pp. 457-459
LA: English
ER: M (Marine)
AB: We now report evidence of monomethyl and dimethyl mercury in the low-oxygen waters of the Equatorial Pacific. The presence of these species has important implications for our understanding of the biogeochemical cycling of mercury in the marine environment. Although the source of monomethyl mercury in open-ocean fish is still unknown, our data show that a pathway exists for the accumulation of methylated mercury in marine pelagic fish.
AN: 2382786
1260 of 1521
TI: Estimation of forms of phosphorus in the Venoge River during storm events.
OT: Estimation des formes du phosphore dans la riviere Venoge en crue
AU: Zhang,-L.; Gregor,-D.J.; Vernet,-J.P.
AF: Inst. F.A. Forel, Univ. Geneva, 10 Route de Suisse, CH-1290 Versoix, Switzerland
CO: 2. Conf. Int. des Limnologues d'Expression Francaise, Aussois (France), 24-28 May 1988
SO: REV.-SCI.-EAU. 1989. vol. 2, no. 4, pp. 709-720
LA: French
ER: F (Freshwater)
AB: To gain a better understanding of phosphorus transport in a storm-dependent river system, water samples were collected near the mouth of the River Venoge, Switzerland, during 5 storm events. A multivariate progressive analysis of the measured P data set shows that total particulate P (TPP) can be estimated as a function of two parameters, the % of a suspended sediment (SS) fraction coarser than 63 mu m and the soluble reactive phosphorus (SRP) concentration measured in filtered water. On the other hand, general statistical relationships exist between the various forms of phosphorus. Total soluble phosphorus (TSP) is dependent upon SRP. Organic phosphorus (OP) and non-apatite inorganic phosphorus (NAIP) can be approximately assessed from TPP, measured or calculated. Then, apatite phosphorus (AP), inorganic phosphorus (IP) and total phosphorus in raw water can be calculated by means of summation/substraction operations.
AN: 2379637
1261 of 1521
TI: Responses in bacterial activity to changing conditions in plankton -- probable controlling mechanisms.
AU: Simek,-K.; Fuksa,-J.K.
CO: Int. Conf. on Reservoir Limnology and Water Quality, Ceske Budejovice (Czechoslovakia), 15 Jun 1987
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-CONFERENCE-ON-RESERVOIR-LIMNOLOGY-AND-WATER-QUALITY.-1.-PHYSICAL-LIMNOLOGY,-MATHEMATICAL-MODELS-AND-MICROBIAL-DECOMPOSITION. Henderson-Sellers,-B.;Straskrabova,-V.-eds. 1989. no. 33 pp. 239-248
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 33
LA: English
ER: F (Freshwater)
AB: Parameters of total activity of bacterioplankton were determined by means of super(14)C-glucose uptake (V sub(max)) and the incorporation of tritiated amino acids (AA). Parameters of individual activity were determined by the autoradiographic method using AA (% of metabolizing cells) and super(3)H-thymidine (% of "probably dividing" cells) during both seasonal and diel cycles. A close relationship was found between microbial activity and the diel cycle of photosynthesis. On a seasonal time-scale, significant relationships were found between counts of metabolizing bacteria and phytoplankton biomass. The relationship between the former and the biomass of Cladocera) was even more significant.
AN: 2379309
1262 of 1521
TI: Vertical distribution of planktonic bacteria and its seasonal changes in a shallow reservoir.
AU: Markosova,-R.; Benediktova,-M.; Volkova,-A.
CO: Int. Conf. on Reservoir Limnology and Water Quality, Ceske Budejovice (Czechoslovakia), 15 Jun 1987
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-CONFERENCE-ON-RESERVOIR-LIMNOLOGY-AND-WATER-QUALITY.-1.-PHYSICAL-LIMNOLOGY,-MATHEMATICAL-MODELS-AND-MICROBIAL-DECOMPOSITION. Henderson-Sellers,-B.;Straskrabova,-V.-eds. 1989. no. 33 p. 257
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 33
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: The authors tried to find a correlation between seasonal changes of vertical distribution of planktonic bacteria and the fluctuations of the organic material in the water column. In the Hostivar reservoir (up to 130 mu g/l chlorophyll-a) the phytoplankton should be considered as a main source of organic bacterial nutrients. Seasonal changes in heterotrophic mesophilic bacteria, coliform bacteria, faecal streptococci and direct counts of bacteria were studied during two following seasons. The results were compared with fluctuations of temperature, oxygen and ammonium content, chlorophyll-a concentration, BOD sub(1) and BOD sub(5). The vertical distribution revealed maximum counts at a maximal depth 7 metres: 8.8 x 10 super(6) cells/ml. The epilimnial bacterial counts correlated with those of the phytoplankton, whereas bacterial counts in the hypolimnion were in a correlation with ammonium nitrogen. Phytoplankton was identified as a main source of organic nutrients in the reservoir. The contribution to the total nutrient pool was calculated to be 44 and 57% in 1982 and 1983, respectively.
AN: 2379241
1263 of 1521
TI: Bacterial utilization of photosynthetically produced dissolved and particulate organic matter and the role in C-flux of Lake Stechlin.
AU: Babenzien,-C.; Babenzien,-H.-D.
CO: Int. Conf. on Reservoir Limnology and Water Quality, Ceske Budejovice (Czechoslovakia), 15 Jun 1987
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-CONFERENCE-ON-RESERVOIR-LIMNOLOGY-AND-WATER-QUALITY.-1.-PHYSICAL-LIMNOLOGY,-MATHEMATICAL-MODELS-AND-MICROBIAL-DECOMPOSITION. Henderson-Sellers,-B.;Straskrabova,-V.-eds. 1989. no. 33 pp. 225-235
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 33
LA: English
ER: F (Freshwater)
AB: The aim of this study was to quantify the microbial capacity in relation to primary production in C-flux of oligotrophic Lake Stechlin. Primary production, exudation, and bacterial assimilation of exudates were measured with the super(14)C-method and a particle size fractionation technique. Production of super(14)CO sub(2) was employed as an estimate of the mineralization rate. With natural phytoplankton populations average exudation rates of 50% in the oligotrophic Lake Stechlin and 20% in the eutrophic Lake Dagow were obtained. On average 20% and 8% of the primary production respectively was assimilated by the bacterial population in the two lakes. 40 to 90% of the bacterial production was based on the utilization of exudates.
AN: 2378113
1264 of 1521
TI: Oxygen and nitrate new production and remineralization in the North Atlantic subtropical gyre.
AU: Sarmiento,-J.L.; Thiele,-G.; Key,-R.M.; Moore,-W.S.
AF: Atmos. and Oceanic Sci. Program, Princeton Univ., Princeton, NJ 08540, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1990. vol. 95, no. C10, pp. 18303-8315
LA: English
ER: M (Marine)
AB: New estimates are obtained of oxygen utilization rates on isopycnal surfaces in the North Atlantic subtropical gyre thermocline based on tritium inventories (2.4-3.5 mol m super(-2)/yr) and super(228)Ra measurements (8.5 plus or minus 0.8 mol m super(-2)/yr). Arguments are given for why the tritium inventory oxygen utilization rate estimate may be too low. The super(228)Ra results are combined with recent estimates of oxygen utilization within the thermocline as well as estimates of oxygen production in the mixed layer, to suggest a tentative overall oxygen balance for the whole water column.
AN: 2375509
1265 of 1521
TI: Abiotic transformations of iron and phosphate in humic lake water revealed by double-isotope labeling and gel filtration.
AU: Jones,-R.I.; Salonen,-K.; de-Haan,-H.
AF: Div. Biol. Sci., Inst. Environ. and Biol. Sci., Univ. Lancaster, Lancaster LA1 4YQ, UK
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 2, pp. 491-497
LA: English
ER: F (Freshwater)
AB: Abiotic transformations of Fe and PO sub(4) super(3-) in humic water from Finnish forest lakes were studied by Sephadex G-100 gel filtration following incubation of filtered (0.2 mu m) epilimnetic water samples to which both super(55)FeCl sub(3) multiplied by 6H sub(2)O and super(32)PO sub(4) super(3-) had been added. The simultaneous movement of super(55)Fe and super(32)P to higher molecular-weight fractions (10,000-20,000 MW) depended on the presence of dissolved humic substances (DHS). In the absence of DHS almost all super(55)Fe, probably as inorganic hydrolyzed iron particles, sorbed to the Sephadex. In the absence of quasi-equilibrium between free and DHS-bound super(32)PO sub(4) super(3-), the DHS-Fe-PO sub(4) super(3-) complex readily released super(32)PO sub(4) super(3-)-P. Compared to the super(32)P binding, super(55)Fe binding was rapid. More than 20% of the Fe had been bound after only 1 min, whereas for labeled PO sub(4) super(3-) this percentage was reached only after 24 h.
AN: 2368760
1266 of 1521
TI: Algal use of sedimentary phosphorus from an Amazon floodplain lake: Implications for total phosphorus analysis in turbid waters.
AU: Engle,-D.L.; Sarnelle,-O.
AF: Dep. Biol. Sci., Univ. California, Santa Barbara, CA 93106, USA
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 2, pp. 483-490
LA: English
ER: F (Freshwater)
AB: Chemical forms of P and and their availabilities to Selenastrum capricornutum were measured in sediments collected from Lago Calado, an Amazon floodplain lake. Postbioassay analysis confirmed that Selenastrum used similar to 60-70% of the P in the NaOH-extracted fraction during a 9-d incubation. No evidence for algal use of Ca-bound P or organic P was found. Methodological comparisons revealed that persulfate digestion may not adequately recover algal-available particulate P in waters high in inorganic turbidity. An average of 26% of the algal-available P in Amazon River water was in particulate form.
AN: 2368606
1267 of 1521
TI: Biogeochemistry of carbon in the Amazon River.
AU: Richey,-J.E.; Hedges,-J.I.; Devol,-A.H.; Quay,-P.D.; Victoria,-R.; Martinelli,-L.; Forsberg,-B.R.
AF: Sch. Oceanogr. and Quaternary Res. Cent., Univ. Washington, Seattle, WA 98195, USA
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 2, pp. 352-371
LA: English
ER: F (Freshwater)
AB: Depth-integrated, discharge-weighted water samples were collected over 1,800 km of the Amazon River on 8 cruises at different stages of the hydrograph, 1982-1984. Fine (FPOC, < 63 mu m) and coarse (CPOC, > 63 mu m) particulate organic carbon as weight percentage of suspended sediment varied between 0.9-1.5% for FPOC and 0.5-3.4% for CPOC. Concentrations of FPOC ranged from 5 mg/liter upriver to 2 mg/liter downriver in the mainstem and from 6 mg/liter in the Rio Madeira to < 1 in the Rio Negro. CPOC had similar distribution patterns, but with concentrations 15-30% those of FPOC. Dissolved organic carbon (DOC) average 4-6 mg/liter in the mainstem and up to 12 mg/liter in the Rio Negro. Upriver dissolved inorganic carbon (DIC) concentrations of about 1,200 mu M were diluted by tributaries and floodplain drainage to 600 mu M at the most downriver site.
AN: 2367693
1268 of 1521
TI: Diel cycles in microbial manganese oxidation and manganese redox speciation in coastal waters of the Bahama Islands.
AU: Sunda,-W.G.; Huntsman,-S.A.
AF: NMFS, NOAA, Southeast Fish. Cent., Beaufort Lab., Beaufort, NC 28516-9722, USA
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 2, pp. 325-338
LA: English
ER: M (Marine)
AB: We observed pronounced diel cycles in formation rates of particulate Mn in coastal waters of the Bahama Islands. Specific rates during the day were 1/20th-1/70th of maximum nighttime rates and there was an associated 3-5-fold decrease in the ratio of particulate to dissolved Mn during the day. The strong suppression of rates after sunrise probably results from photoinhibition of microbially catalyzed Mn(II) oxidation. The decrease in Mn(II) oxidation during the day along with photodissolution of Mn oxides observed in previous investigations appear to contribute to the increased ratio of dissolved Mn to particulate Mn oxides during daylight.
AN: 2367630
1269 of 1521
TI: Microbial biomass in the coastal plume of Chesapeake Bay: Phytoplankton-bacterioplankton relationships.
AU: Malone,-T.C.; Ducklow,-H.W.
AF: Horn Point Environ. Lab., Univ. Maryland Syst., Cent. Environ. and Estuarine Stud., P.O. Box 775, Cambridge, MD 21613, USA
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 2, pp. 296-312
LA: English
ER: M (Marine); B (Brackish)
AB: Turnover rate of suspended organic matter (POC) increased seasonally with temperature as the proportions of POC accounted for by bacterioplankton increased relative to phytoplankton. The proportion of phytoplankton productivity that cycled through bacterioplankton averaged 13% and showed little seasonal variability. These results imply changes in the pathways and rates by which phytoplankton and bacterioplankton production were consumed or exported from the plume. Time series of 1-3 d next to surface drifters within the plume provided some insight into the nature of these changes. In February when the turnover rate of POC was low, phytoplankton biomass declined relative to bacterioplankton due to sedimentation of large diatoms. Low bacterioplankton biomass was associated with high rates of predation by heterotrophic microflagellates. In August when POC was turning over rapidly, phytoplankton biomass declined relative to bacterioplankton due to selective grazing by copepods.
AN: 2367576
1270 of 1521
TI: Estimation of ammonification and ammonium assimilation in surficial coastal and estuarine sediments.
AU: Sumi,-T.; Koike,-I.
AF: Chikushigaoka High Sch., 2-13-1 Noma Minami-ku Fukuoka, 815, Japan
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 2, pp. 270-286
LA: English
ER: M (Marine); B (Brackish)
AB: Ammonification and NH sub(4) super(+) assimilation is slurries of surface sediments from Japanese coastal and estuarine areas were studied with super(15)NH sub(4) super(+) tracers. In completely aerobic sediments, where NO sub(3) super(-) reduction is negligible, the Blackburn super(15)NH sub(4) super(+) dilution model can be applied to estimate the ammonification rate after a correction for nitrification is made. In semiaerobic sediments, where significant NO sub(3) super(-) reduction occurs, a mathematical model based on the change of super(15)NH sub(4) super(+) and super(15)NO sub(3) super(-) with time was successfully applied to estimate the ammonification rate. The rate of NH sub(4) super(+) assimilation can be obtained directly from the incorporation of super(15)NH sub(4) super(+) into particles in the sediments after correcting for super(15)NH sub(4) super(+) dilution during incubation. The rate of ammonification ranged from 5.8 to 220 ng-atoms N (g sediment) super(-1)/h and that of NH sub(4) super(+) assimilation ranged from 6.2 to 114, indicating both large seasonal and local variations. Both NH sub(4) super(+) assimilation and ammonification were significantly correlated with ATP biomass, NH sub(4) super(+), and organic N contents in sediments.
AN: 2367263
1271 of 1521
TI: Rapid ammonium cycling and concentration-dependent partitioning of ammonium and phosphate: Implications for carbon transfer in planktonic communities.
AU: Suttle,-C.A.; Fuhrman,-J.A.; Capone,-D.G.
AF: Mar. Sci. Inst., Univ. Texas at Austin, P.O. Box 1267, Port Aransas, TX 78373-1267, USA
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 2, pp. 424-433
LA: English
ER: M (Marine)
AB: A short-lived radioactive isotope of nitrogen ( super(13)N, half-life = 10 min) of very high specific activity (> 100 mCi/ mu mol) was used to study NH sub(4) super(+) uptake at near-ambient concentrations in natural planktonic communities. The turnover times of the dissolved NH sub(4) super(+) pool in Long Island Sound ranged from tens of hours between April and early June to a fraction of an hour between mid-June and late July. Up to 50% of the ambient NH sub(4) super(+) flux into particulate material from Long Island Sound was attributable to organisms passing 1.0- mu m polycarbonate filters. Partitioning of NH sub(4) super(+) uptake among size classes was, however, very concentration-dependent. A 0.5 mu M addition resulted in an increase in NH sub(4) super(+) uptake by the > 3- mu m size class of from 33% to > 80% of the total. Because slight increases in NH sub(4) super(+) and PO sub(4) super(3-) concentration result in greater uptake by larger organisms with higher C:N and C:P ratios, distributing these nutrients in "patches" of elevated concentration results in more C being transferred to higher level consumers.
AN: 2367244
1272 of 1521
TI: Variations in sedimentary carbon remineralization rates in the White Oak River estuary, North Carolina.
AU: Kelley,-C.A.; Martens,-C.S.; Chanton,-J.P.
AF: Curric. Mar. Sci., 12-5 Venable Hall CB 3300, Univ. North Carolina, Chapel Hill, NC 27599-3300, USA
SO: LIMNOL.-OCEANOGR. 1990. vol. 35, no. 2, pp. 372-383
LA: English
ER: B (Brackish)
AB: Rates of microbially mediated sedimentary organic carbon remineralization vary along the salinity gradient of the White Oak Estuary. A direct comparison of two sites, one upriver dominated by methanogenesis and one downriver dominated by sulfate reduction, indicates a more rapid rate of remineralization upriver. The uncertainties in the yearly fluxes are calculated from observed in duplicate flux measurements. About 43% of the incoming organic C is remineralized at both sites. The greater remineralization upriver, of which 47% can be attributed to methanogenesis, appears to be supported by rapid decomposition of detritus derived from freshwater, emergent and submersed macrophytes. The high organic C content of these upriver sediments may, however, result from the long-term storage of slower degrading plants.
AN: 2367188
1273 of 1521
TI: Controls on surface water chemistry in the southern Blue Ridge and Piedmont Provinces.
AU: Stauffer,-R.E.
AF: 3633 Humphrey Lane, Lexington, KY 40502, USA
SO: WATER-AIR-SOIL-POLLUT. 1990. vol. 52, no. 1-2, pp. 79-96
LA: English
ER: F (Freshwater)
AB: Using lake and stream data collected during the National Surface Water Survey (NSWS), and corrected for regional wet deposition and local cultural contamination, the role of weathering in supplying base cations C sub(B), silica, and alkalinity is evaluated for the southern Blue Ridge (SBR) and southern Piedmont (SPM) Provinces of the United States. Silicate weathering can account for virtually all of the non-cultural (Na+K) leaving the catchments, consistent with the weathering of feldspars to kaolinite, and in some dilute montane catchments, gibbsite. The net export of divalent C sub(B) (Ca+Mg) represents 62 to 66% (median values) of total C sub(B) export for the regional NSWS index sample populations; the alkalis account for the remainder. The median percentage (Ca+Mg) is significantly lower (53%) for SBR special sites, consistent with their unusual vulnerability to acid deposition. Exchange-leaching currently accounts for < 17% of the divalent C sub(B) mobilized in these SBR and SPM catchments, possibly because of the high regional retention rates for both nitrate and sulfate.
AN: 2366986
1274 of 1521
TI: Relationship of reservoir biogeochemical processes to the structural integrity of the world's first totally roller compacted concrete dam.
AU: Larson,-D.W.
AF: Hydraul. and Hydrol., Water Qual., U.S. Army Corps Eng., Portland Dist., P.O. Box 2946, Portland, OR 97208, USA
CO: Int. Conf. on Reservoir Limnology and Water Quality, Ceske Budejovice (Czechoslovakia), 15-20 Jun 1987
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-CONFERENCE-ON-RESERVOIR-LIMNOLOGY-AND-WATER-QUALITY.-3.-KEY-FACTORS-OF-RESERVOIR-LIMNOLOGY,-EUTROPHICATION,-WATER-QUALITY-AND-ITS-PREDICTION. Lind,-O.T.;Sladecek,-V.;Straskrabova,-V.-eds. 1990. no. 33 pp. 949-964
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 33
LA: English
ER: F (Freshwater)
AB: Willow Creek Dam is a U.S. Army Corps of Engineers flood-control project located on a tributary of the Columbia River (Willow Creek) in north-central Oregon, U.S.A. Willow Creek Reservoir is extremely eutrophic and is well stratified thermally during summer. By August, the reservoir's hypolimnion is anoxic and contains high concentrations of hydrogen sulfide (up to 11 mg/l) and other chemically reduced substances. Apparent defects in the dam's concrete matrix have provided avenues for substantial leakage of hypolimnetic waters. Seepage entering the dam's tunnels and gallery is highly enriched with hydrogen sulfide and dissolved lime. There is concern that oxidation of hydrogen sulfide by chemosynthetic bacteria, producing sulfuric acid, is corroding the dam's concrete.
AN: 2366143
1275 of 1521
TI: Radiocarbon evidence of fossil-carbon cycling in sediments of a nearshore hydrocarbon seep.
AU: Bauer,-J.E.; Spies,-R.B.; Vogel,-J.S.; Nelson,-D.E.; Southon,-J.R.
AF: Mar. Res. Div., Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093, USA
SO: NATURE. 1990. vol. 348, no. 6298, pp. 230-232
LA: English
ER: M (Marine)
AB: Widespread seepage of petroleum and natural gas in the southern California continental borderland provides an opportunity to study the long-term fate and biogeochemical effects of hydrocarbons in nearshore sedimentary environments. The hydrocarbons that enrich seep sediments have been hypothesized to serve as a carbon and energy source for sediment metabolism and infaunal populations. Here we present super(14)C natural abundances in sediment total organic carbon (TOC), pore-water dissolved inorganic carbon (DIC) and infauna from in and around a hydrocarbon seep off southern California which were measured to help test this hypothesis. Concentrations of super(14)C in each pool reflect the admixture of fossil ( super(14)C-depleted) seep-derived carbon with carbon from the euphotic zone. The super(14)C depletion in TOC and DIC increased with proximity to the seepage zone and with sediment depth; super(14)C abundances differed between meiofauna and macrofauna, suggesting that the two groups incorporate fossil carbon in different ways. The results indicate that fossil carbon can indeed comprise a major component of these carbon pools in nearshore seep sediments.
AN: 2363484
1276 of 1521
TI: Global change expedition: Nutrient, chlorophyll-a and primary productivity data, NOAA ship MT. Mitchell , 14 July-6 September 1988.
AU: Frazel,-D.W.; Berberian,-G.A.; Hitchcock,-G.L.
CA: National Oceanic and Atmospheric Adm., Miami, FL (USA). Atlantic Oceanographic and Meteorological Labs.
SO: NOAA-DATA-REP. 1989. 66 pp
NT: NTIS Order No.: PB90-220336/GAR.
RN: NOAA-DR-ERL-AOML-15 (NOAADRERLAOML15)
LA: English
AB: During the period of 14 July-6 September 1988, a multifaceted oceanographic research cruise called the Global Change Expedition was made on the NOAA Ship MT. Mitchell in the North Atlantic Ocean. The objective of the cruise was to study the atmospheric and oceanic processes affecting the biogeochemical cycles of carbon, nitrogen, sulfur, and trace metals. Emphasis was made on compounds of these elements that would influence the radiation balance of the earth and hence, of global climate. Measurements from hydrocasts for nutrients, phytoplankton biomass, and productivity were made on a daily basis during the period. The report represents the biological and chemical (nutrient) data from the cruise. (Prepared in cooperation with Nova Univ. Oceanographic Center, Dania, FL (USA).)
AN: 2362437
1277 of 1521
TI: Distribution of glycosylglycerols and oligosaccharides in the marine environment and their ecological significance in the deep sea.
AU: Sakugawa,-H.; Handa,-N.; Yagi,-K.
AF: Water Res. Inst., Nagoya Univ., Chikusa-ku, Nagoya 464, Japan
SO: MAR.-BIOL. 1990. vol. 106, no. 2, pp. 309-313
NT: Bibliogr.: 36 ref.
LA: English
ER: M (Marine)
AB: Determination of low molecular weight carbohydrates in marine environments indicated that 1-O- beta -D-galactosylglycerol, 6-O- alpha -D-galactosyl-1-O- beta -D-galactosylglycerol, sucrose, laminaribiose and laminaritriose are widely distributed in seawaters, suspended and sinking particles, and sediments in coastal as well as in deep-sea waters (e.g. Mikawa Bay and Sagami Bay, Kumano Nada (offshore Japan), and northwest North Pacific Ocean, Bering Sea and Antarctic Ocean: collections during 1978-1984). Identification of these glycosylglycerols and oligosaccharides in algal cells such as a flagellate (Olisthodisus luteus ), blue-green algae (e.g. Trichodesmium sp.) and a diatom (Reptocylindrus denicus ) strongly suggests that these sugars are photosynthetically produced by algae in the euphotic zone and are then rapidly transported to the deep sea as sinking particles which can be collected by sediment-trap experiments.
AN: 2362355
1278 of 1521
TI: Hydrothermal and microbial processes at Loihi Seamount, a mid-plate hot-spot volcano.
AU: Karl,-D.M.; Brittain,-A.M.; Tilbrook,-B.D.
AF: Dep. Oceanogr., Univ. Hawaii at Manoa, Honolulu, HI 96822, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1989. vol. 36, no. 11A, pp. 1655-1673
LA: English
ER: M (Marine)
AB: Active hydrothermal vents have been discovered at the summit of Loihi Seamount, Hawaii, in an area referred to as Pele's Vents. The active vent field is characterized by iron-rich nontronite deposits, warm (30 degree C) hydrothermal fluids, extensive bacterial mats and by the conspicuous absence of large benthic animals. Chemical analyses of collected water samples has revealed the presence of elevated concentrations of Si, NH super(+)@)d4, PO sub(4)@)u- super(3), dissolved inorganic carbon (DIC), methane (CH sub(4)) and bacterial cells in the discharged vent fluids, relative to ambient bottom seawater. Bacterial mats collected from the vent field are comprised of long filaments coated with Fe precipitates. It is hypothesized that these tubular structures are formed by the growth and metabolism of Fe-oxidizing bacteria.
AN: 2358170
1279 of 1521
TI: The wind-driven "biological pump" and carbon removal in the ocean.
OT: Die Wind-getriebene "biologische Pumpe" und der Kohlenstoffentzug im Ozean
AU: Haake,-B.; Ittekkot,-V.
AF: Geol. Palaeontol. Inst. und Mus., Univ. Hamburg, D-2000 Hamburg, FRG
SO: NATURWISSENSCHAFTEN. 1990. vol. 77, no. 2, pp. 75-79
LA: German
ER: M (Marine)
AB: Fixation of carbon dioxide into organic tissues in the ocean and its subsequent sinking act as a "biological pump" removing CO sub(2) from the atmosphere and surface waters to the deep sea. Most of this sinking occurs in large, biologically formed aggregates made up of organic matter, organism frustules and mineral matter. Strong winds bring nutrient-rich subsurface water to the euphotic zone and increase biological productivity, i.e., CO sub(2) fixation. More importantly, dust particles introduced simultaneously to the sea surface become incorporated into large aggregates thereby increasing densities of settling particles and, as a consequence, effecting the rapid removal of newly fixed organic matter to the deep ocean. These recent findings have important implications for the carbon cycling in the sea.
AN: 2356651
1280 of 1521
TI: Natural abundance of super(15)N in particulate nitrogen and zooplankton in the Chesapeake Bay.
AU: Montoya,-J.P.; Horrigan,-S.G.; McCarthy,-J.J.
AF: Mus. Comp. Zool., Harvard Univ., Cambridge, MA 12138, USA
SO: MAR.-ECOL.-PROG.-SER.. 1990. vol. 65, no. 1, pp. 35-61
NT: Bibliogr.: 36 ref.
LA: English
ER: M (Marine)
AB: Samples of dissolved inorganic nitrogen (DIN), particulate nitrogen (PN), and several species of zooplankton were collected at a series of stations in the main channel of the Chesapeake Bay, USA, during cruises in spring and fall 1984. The overall gradient of DIN concentrations along the axis of the Bay appears to be less important than local processes in determining the distribution of super(15)N in PN. The delta super(15)N of the zooplankton species sampled generally increased with trophic level. The delta super(15)N of the copepod Acartia tonsa was higher than that of PN by 4.2 plus or minus 2.3 ppt (x@u- plus or minus SD) in spring and 3.3. plus or minus 1.0 ppt (x@u- plus or minus SD) in fall. Similarly, delta super(15)N of the ctenophore Mnemiopsis leidyi was higher than that of A. tonsa by 2.0 plus or minus 2.6 ppt (x@u- plus or minus SD) in spring and 3.3 plus or minus 1.0 ppt (x@u- plus or minus SD) in fall. A reversal of the usual relationship between A. tonsa and M. leidyi occurred near the southern end of the Bay during spring, where delta super(15)N of the copepod was greater than that of the ctenophore by as much as 4.9 ppt.
AN: 2354709
1281 of 1521
TI: Chromium biogeochemical cycle in Abu Kir Bay, East of Alexandria, Egypt.
AU: Aboul-Dahab,-O.
AF: Oceanogr. Dep., Fac. Sci., Univ. Alexandria, Alexandria, Egypt
SO: ESTUAR.-COAST.-SHELF-SCI. 1989. vol. 29, no. 4, pp. 327-340
LA: English
ER: M (Marine); B (Brackish)
AB: Abu Kir Bay, east of Alexandria, is affected by two main point sources of pollution, namely Tabia Pumping Station and Lake Edku Outlet. Chromium was measured in the Bay effluents, sea water, marine organisms of different trophic levels, and sediments. The surface distribution of Cr in the coastal waters showed the impact of Tabia Pumping Station on the Bay. Algae and crabs play a critical role in the biological transport of Cr and can be considered the best accumulators of the element.
AN: 2354691
1282 of 1521
TI: NFLUX: A test of vertical nitrogen flux by diel migrant biota.
AU: Longhurst,-A.R.; Bedo,-A.; Harrison,-W.G.; Head,-E.J.H.; Horne,-E.P.; Irwin,-B.; Morales,-C.
AF: Biol. Oceanogr. Div., Bedford Inst. Oceanogr., Dep. Fish. and Oceans, P.O. Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1989. vol. 36, no. 11A, pp. 1705-1719
LA: English
ER: M (Marine)
AB: At a station (NFLUX), occupied for 10 days in the northern Sargasso Sea, we assembled data to test the hypothesis that diel migrant biota in the open ocean induce a downward flux of dissolved inorganic nitrogen that is significant in relation to the passive flux under gravity of particulate organic nitrogen at the base of the photic zone. We found that NH super(+)@)d4 excretion rates by day at depths below the photic zone were approximately 8% of particulate nitrogen flux obtained by a sediment trap array at the same depth. This figure is in the lower part of the range of values calculated previously for 10 published station data sets; we attribute this to the quite high rate of passive flux relative to primary production at the NFLUX station.
AN: 2354663
1283 of 1521
TI: Mass balance of biogeochemically active materials (C, N, P,) in a hypersaline gulf.
AU: Smith,-S.V.; Veeh,-H.H.
AF: Hawaii Inst. Mar. Biol., Univ. Hawaii at Manoa, 1000 Pope Rd., Honolulu, HI 96822, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1989. vol. 29, no. 3, pp. 195-215
LA: English
ER: M (Marine); B (Brackish)
AB: We have examined the mass balance of water, salt, C, N, and P in Spencer Gulf, a large inverse estuary in South Australia. The fluxes of C, N, and P are biologically mediated, and we look for a plausible interaction among these fluxes. The CO sub(2) system appears remarkably "balanced" by its fluxes - to relatively constant pH, PCO sub(2), and calcite saturation state. We conclude that supply of PO sub(4) super(3-) largely controls characteristics of C and N flux. The controls postulated for P include CaCO sub(3) precipitation, CO sub(2) gas flux, organic C production, and N fixation.
AN: 2353244
1284 of 1521
TI: Bacterial cycling of minerals that affect plant growth in waterlogged soils: A review.
AU: Laanbroek,-H.J.
AF: Inst. Ecol. Res., R. Neth. Acad. Sci., P.O. Box 40, 6666 ZG Heteren, Netherlands
CO: Symp. in Adaptation of Plants to Flooding, Wageningen (Netherlands), Dec 1988
SO: ADAPTATION-OF-PLANTS-TO-FLOODING. Blom,-C.W.P.M.-ed. 1990. vol. 38, no. 1 pp. 109-125
ST: AQUAT.-BOT. vol. 38, no. 1
NT: Special issue.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Plant growth in waterlogged soils may be greatly affected by reduced minerals such as ammonium, manganous and ferrous ions, and sulphide. A more detailed description is given of the microbial and chemical processes that lead to reduced minerals, as well as of the micro-organisms involved. Reduction processes do not occur simultaneously, but consecutively according to a fixed sequence: oxygen, nitrate, manganese (IV) oxide, ferric oxide, sulphate and carbon dioxide. Special attention is paid to the microbial mechanisms of mutual exclusion of reduction processes. Re-oxidation of reduced minerals occurs at the oxic-anoxic interfaces in the flooded soil, i.e. at the oxidized upper layers of the soil and in the oxidized rhizosphere of waterlogged plants with aerenchyma. The micro-organisms involved in the oxidation processes with oxygen are mentioned in relation to their ecological niches.
AN: 2352450
1285 of 1521
TI: The evolution of saline lake waters: Gradual and rapid biogeochemical pathways in the Basotu Lake District, Tanzania.
AU: Kilham,-P.; Cloke,-P.L.
AF: Dep. Biol., Univ. Michigan, Ann Arbor, MI 48109-1048, USA
CO: 4. Int. Symp. on Athalassic (Inland) Saline Lakes, Banyoles (Spain), 2-8 May 1988
SO: SALINE-LAKES. Comin,-F.A.;Northcote,-T.G.-eds. 1990. vol. 197 pp. 35-50
ST: HYDROBIOLOGIA. vol. 197
LA: English
ER: B (Brackish)
AB: The biogeochemical evolution of solutes markedly alters the chemistry in the closed-basin maar lakes that comprise the Basotu Lake District (Tanzania, East Africa). Examination of 11 (out of 13) lakes in the Basotu Lake District identified two distinct evolutionary pathways: a gradual path and a rapid path. During the course of biogeochemical evolution these waters follow either the gradual path alone or a combination of the gradual and rapid paths. Solute evolution along the gradual path is determined by all the biogeochemical processes that for these waters appear to be tightly coupled to evaporative concentration (e.g. mineral precipitation, sorption and ion exchange, CO sub(2) degassing, and sulfate reduction).
AN: 2351357
1286 of 1521
TI: Role of zooplankton in the nitrogen cycle off the west coast of the South Island, New Zealand, winter 1987.
AU: James,-M.R.
AF: Taupo Res. Lab., Div. Water Sci., Dep. Sci. and Ind. Res., P.O. Box 415, Taupo, New Zealand
SO: N.Z.-J.-MAR.-FRESHWAT.-RES. 1989. vol. 23, no. 4, pp. 507-518
LA: English
ER: M (Marine)
AB: Zooplankton abundance, feeding, and ammonia regeneration rates were measured along three transects off the west coast of the South Island, New Zealand, in winter (July) 1987. Crustacean nauplii and copepodites dominated the 55-200 mu m fraction of the microzooplankton. Tintinnid population dynamics were related to the degree of freshwater influence. Tintinnid species with silica-encrusted bowls were common close inshore and species with no encrustations were common offshore. The most abundant macrozooplankton were the small copepod Acartia ensifera, Paracalanus indicus, Oithona similis, Centropages aucklandicus , and Clausocalanus jobei. A. ensifera dominated at the inshore stations, whereas the outer stations had a mixture of neritic/outer shelf and oceanic species.
AN: 2350574
1287 of 1521
TI: Nitrogen assimilation by three size fractions of the winter phytoplankton off Westland, New Zealand.
AU: Chang,-F.H.; Vincent,-W.F.; Woods,-P.H.
AF: New Zealand Oceanogr. Inst., Div. Water Sci., Dep. Sci. and Ind. Res., Priv. Bag, Kilbirnie, Wellington, New Zealand
SO: N.Z.-J.-MAR.-FRESHWAT.-RES. 1989. vol. 23, no. 4, pp. 491-505
LA: English
ER: M (Marine)
AB: The assimilation of ammonium, nitrate, and urea by the phytoplankton community off the Westland coast was measured in a detailed series of super(15)N-assays in mid winter, 1987. The average nitrogen (N) uptake rates for the three substrates for three size classes of phytoplankton (< 2, < 20, < 200, mu m) followed the distribution of biomass as measured by chlorophyll a, with higher values inshore. Nitrate accounted for 56% of the total N utilised by the entire community (< 200 mu m), whereas ammonium and urea made up c. 19 and 25%, respectively. These data imply that new N provided a greater nutritional source than regenerated N for the growth of the dominant size components (< 2, 2-20 mu m) of the midwinter phytoplankton community.
AN: 2350559
1288 of 1521
TI: Distribution of arsenite and total dissolved arsenic in major French estuaries: Dependence on biogeochemical processes and anthropogenic inputs.
AU: Seyler,-P.; Martin,-J.M.
AF: Inst. Biogeochim. Mar., UA 386 CNRS, Ec. Norm. Super. 1, Rue Maurice Arnoux, F-92120 Montrouge, France
SO: MAR.-CHEM. 1990. vol. 29, no. 2-3, pp. 277-294
LA: English
ER: B (Brackish)
AB: The distribution of arsenite (As (III)), total dissolved arsenic and particulate arsenic was studied in major French rivers/estuaries which are representative of polluted, unpolluted, macrotidal and stratified systems. In the Rhone Estuary (with flushing time of the order of 1 day) the maximum of dissolved arsenic (25-50 nM) occurring in the low-salinity zone is related to the variability of the river input. In the Gironde Estuary (flushing time 20-86 days) arsenite and total dissolved As concentrations vs. chlorinity plots show a maximum (45 nm for dissolved arsenic) located in the low-salinity zone within the turbidity maximum. In the Loire fluvio-estuarine system the maxima of arsenite (15 nM) and total dissolved arsenic (25 nM) are attributed to the anthropogenic inputs from land-based industries, and especially from the coal-power plant. The dissolved arsenic discharge has been estimated at 40 tons/yr.
AN: 2336702
1289 of 1521
TI: Downward flux of particulate fatty acids in the Central Arabian Sea.
AU: Reemtsma,-T.; Haake,-B.; Ittekkot,-V.; Nair,-R.R.; Brockmann,-U.H.
AF: Geol.-Palaeontol. Inst. und Mus., Univ. Hamburg, Bundesstr. 55, 2000 Hamburg 13, FRG
SO: MAR.-CHEM. 1990. vol. 29, no. 2-3, pp. 183-202
LA: English
ER: M (Marine)
AB: Particulate matter collected at 732 and 2914 m during a time-series sediment trap experiment (sampling interval 13 days) in the Central Arabian Sea (14 degree 29'N, 64 degree 46'E; water depth 4016 m) was analysed for its fatty acid and organic carbon contents. The sampling period covered the summer monsoon of 1986. Contents of organic carbon and fatty acid decrease with increasing particle fluxes. At 732 m fatty acids account for 0.6-4% of organic carbon. Particulate organic matter collected during high productivity and high-flux periods exhibits signs of less intense degradation within the surface layers. Selective degradation of fatty acids diminishes their contribution to organic carbon in the deeper trap (0.3-0.7%). Despite this, the seasonality in fatty acid flux is maintained down to the deep ocean.
AN: 2336638
1290 of 1521
TI: Element budgets of two contrasting catchments in the Black Forest (Federal Republic of Germany).
AU: Feger,-K.H.; Brahmer,-G.; Zoettl,-H.W.
AF: Inst. Soil Sci. and Forest Nutr., Albert-Ludwig-Univ., D-7800 Freiburg im Breisgau, FRG
SO: J.-HYDROL.-AMST.. 1990. vol. 116, no. 1-4, pp. 85-99
LA: English
AB: Rainfall and throughfall inputs of all major cations and anions, via open-field bulk precipitation and canopy throughfall, are compared with streamwater outputs in two forested catchments at higher altitudes of the Black Forest. The sites differ considerably in terms of bedrock geology, soil type soilwater characteristics, topography, and forest management history. Deposition at both sites is almost equal and, in contrast to other forest areas in Central Europe, of a low-to-moderate level. Dry deposition does not seem to play an important role. Distinct differences in the elemental output emerge owing to the differing site conditions. At Villingen, deposited nitrogen is almost totally retained, whereas at Schluchsee, nitrogen output and input are of the same order of magnitude. This is consistent with the different nitrogen nutrition level of the stands, microbial turnover in the soil, and former management practices (change of tree species, excessive nutrient export). Sulphur is not retained in either of the catchments.
AN: 2334089
1291 of 1521
TI: Longitudinal patterns of concentration-discharge relationships in stream water draining the Hubbard Brook Experimental Forest, New Hampshire.
AU: Lawrence,-G.B.; Driscoll,-C.T.
AF: Dep. Plant and Soil Sci., Deering Hall, Univ. Maine, Orono, ME 04469, USA
SO: J.-HYDROL.-AMST.. 1990. vol. 116, no. 1-4, pp. 147-165
LA: English
ER: F (Freshwater)
AB: Longitudinal variations of concentration-discharge relationships and chemical fluxes were evaluated in two headwater streams at the Hubbard Brook Experimental Forest, New Hampshire. At high elevations changes in subsurface flow paths explained variations in H super(+), inorganic Al and Si concentrations, whereas variations of DOC concentration were inconsistent with this mechanism. Flow responses of middle and low elevation subcatchments were influenced by variable contributions of hydrologic source areas and the elevational concentration gradient which exists in these catchments, but in most cases were not consistent with responses predicted by changes in flow paths. Spatial patterns of chemical fluxes indicate that catchment neutralization processes increased in effectiveness in the downslope direction. However, this pattern can be interrupted by secondary tributaries, which originate in variable source areas that contribute acidic surface runoff during high flow conditions.
AN: 2334067
1292 of 1521
TI: Hydrogeochemical variations in Hafren forest stream waters, Mid-Wales.
AU: Neal,-C.; Smith,-C.J.; Walls,-J.; Billingham,-P.; Hill,-S.; Neal,-M.
AF: Inst. Hydrol., Maclean Build., Crowmarsh Gifford, Wallingford OX10 8BB, UK
SO: J.-HYDROL.-AMST.. 1990. vol. 116, no. 1-4, pp. 185-200
LA: English
ER: F (Freshwater)
AB: Results are presented to assess the effects of conifer planting/harvesting and acidic oxide deposition on streamwater quality in a 25 to 45-year-old sitka spruce plantation on acid moorland. Hafren forest streamwater chemistry varies for different components: nitrate, bromide, total iodine and total organic carbon show seasonal oscillations varying in phase and amplitude; aluminium and hydrogen ion concentrations vary as a function of flow; manganese and cobalt remain approximately constant except under very dry conditions when concentrations reduce by up to 10 fold. No direct link exists between rain and streamwater chemistry: streamwater chemistry variations are determined primarily by hydrological and chemical reactions in the surface organic-rich soils and the underlying inorganic soils/bedrock. Reactions in the organic-rich horizons involve the generation of acidic conditions and the mobilization/transport of transition metals that can be easily hydrolysed. Biologically mediated breakdown processes determine, in part, the hydrochemical behaviour of dissolved organic carbon, the nutrients, bromine and iodine.
AN: 2334043
1293 of 1521
TI: Biogeochemical cycling of manganese at hydrothermal vents.
AU: Tebo,-B.M.
CA: Scripps Inst. of Oceanography, La Jolla, CA (USA). Marine Biological Research Div.
SO: 1990. 4 pp
NT: NTIS Order No.: AD-A219 360/5/GAR. Contract N00014-87-K-0532.
LA: English
ER: M (Marine)
AB: The interactions between bacteria and metals in the ocean are profoundly important both in environments with high levels of metals, such as hydrothermal vents. Metals affect primary productivity by both metal limitation of phytoplankton growth and by serving as a potential energy source for bacterial (autotrophic) growth. In addition, the highly charged surfaces of metal oxide particles, which, to a large extent, are microbially produced, govern much trace metal and organic geochemistry. The role these oxides surfaces play is evident both in hydrothermal vent plumes (which, because they are dispersed hundreds of kilometers away from venting sources, have a profound influence on the chemistry and ecology of the deep sea) as well as in the photic zone.
AN: 2333795
1294 of 1521
TI: Precipitation, throughfall, soil solution and stream-water chemistry in a holm-oak (Quercus ilex ) forest.
AU: Roda,-F.; Avila,-A.; Bonilla,-D.
AF: Cent. Rec. Ecol. i Apl. For., Univ. Auton. Barcelona, 08193 Bellaterra, Spain
SO: J.-HYDROL.-AMST.. 1990. vol. 116, no. 1-4, pp. 167-183
LA: English
ER: F (Freshwater)
AB: Bulk precipitation, throughfall, soil solution at 20 and 40 cm depths, and stream water were monitored for 2-4 years in a holm-oak forest on schists in the Montseny Mountains (NE Spain). Bulk precipitation was mildly acidic, with Ca super(2+) and SO sub(4)@) super(2)-a)s dominant ions. Canopy interactions produced a throughfall less acidic than bulk precipitation and enriched in all other ions. Large amounts of K super(+) were leached from the canopy. Magnesium in net throughfall behaved similarly to K super(+), and it is concluded that leaching makes a major contribution to Mg super(2+) enrichment beneath the canopy. Judging from the moderate increase of Na super(+) and Ca super(2+) in throughfall, dry deposition rates for both marine and continental aerosols were low in the studied stand, probably because of its sheltered topographic position within a well-vegetated massif, coupled with moderate tree height and low canopy roughness. It is concluded that: (1) this forest does not currently receive acidic atmospheric deposition; (2) the neutralization capacity of the soil-bedrock system is quite high; (3) biotic regulation and silicate weathering are the major processes shaping the solution biogeochemistry in this Mediterranean forest ecosystem.
AN: 2333631
1295 of 1521
TI: Effects of vegetation type on the biogeochemistry of small catchments (Mont Lozere, France).
AU: Lelong,-F.; Dupraz,-C.; Durand,-P.; Didon-Lescot,-J.F.
AF: Lab. Hydrogeol. et UA 724, CNRS, Univ. Orleans, B.P. 6759, 45067 Orleans, Cedex 2, France
SO: J.-HYDROL.-AMST.. 1990. vol. 116, no. 1-4, pp. 125-145
LA: English
ER: F (Freshwater)
AB: Input-output budgets are presented for 3 granitic catchments, with contrasting vegetation types (Spruce, Beech and grassland), for the Mont Lozere region of France. Budget results are compared with information for analogous catchments with varying atmospheric pollution loading. Comparisons show relatively small losses of cations and marked sulphate retention in the soils (particularly for the beech and grassland sites) of the Mont Lozere catchments. Retention of sulphate may be underestimated, particularly for the spruce site, owing to occult and dry deposition inputs which have not been measured. Specific effects of the vegetation type upon the soil dynamics and the biological functioning of the ecosystem are described. Losses of the base cations are least significant for the beech forest, and this is linked to low bicarbonate production coupled with high sulphate retention in the soil.
AN: 2333607
1296 of 1521
TI: Hydrological and hydrochemical fluxes through vegetation and soil in the Allt a'Mharcaidh, western Cairngorms, Scotland: Their effect on streamwater quality.
AU: Ferrier,-R.C.; Walker,-T.A.B.; Harriman,-R.; Miller,-J.D.; Anderson,-H.A.
AF: Macaulay Land Use Res. Inst., Craigiebuckler AB9 2QJ, UK
SO: J.-HYDROL.-AMST.. 1990. vol. 116, no. 1-4, pp. 251-266
LA: English
ER: F (Freshwater)
AB: A detailed investigation of the hydrochemical alteration of input water by vegetation and soils was undertaken in an upland catchment in the Cairngorm Mountain region of Scotland. The composition of catchment outflow water reflects the hydrological routing of water through different soil horizons and the importance of long residence time water. There is uptake of nitrogen and neutralization of incoming anthropogenic acidity by the vegetation, and sulphate adsorption in the mineral soils. Streamwater quality is dominated by the contribution of long residence time water, especially during base flow. Sulphate retention and cation release are the major neutralization mechanisms buffering outflow chemistry at this site.
AN: 2333567
1297 of 1521
TI: A thiosulfate shunt in the sulfur cycle of marine sediments.
AU: Joergensen,-B.B.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, 8000 Aarhus C, Denmark
SO: SCIENCE-WASH.. 1990. vol. 249, no. 4965, pp. 152-154
LA: English
ER: M (Marine)
AB: The oxidation of sulfide, generated by bacterial sulfate reduction, is a key process in the biogeochemistry of marine sediments, yet the pathways and oxidants are poorly known. By the use of super(35)S-tracer studies of the S cycle in marine and freshwater sediments, a novel shunt function of thiosulfate (S sub(2)O sub(3) super(2-)) was identified. The S sub(2)O sub(3) super(2-) constituted 68 to 78 percent of the immediate HS super(-)-oxidation products and was concurrently (i) reduced back to HS super(-), (ii) oxidized to SO sub(4) super(2-), and (iii) disproportionated to HS super(-) + SO sub(4) super(2-). The small thiosulfate pool is thus involved in a dynamic HS super(-)-S sub(2)O sub(3) super(2-) cycle in anoxic sediments. The disproportionation of thiosulfate may help account for the large difference in isotopic composition ( super(34)S/ super(32)S) of sulfate and sulfides in sediments and sedimentary rocks.
AN: 2331411
1298 of 1521
TI: Two-isotope characterization of N sub(2)O in the Pacific Ocean and constraints on its origin in deep water.
AU: Kim,-Kyung-Ryul; Craig,-H.
AF: Dep. Oceanogr., Seoul Natl. Univ., Seoul 151-742, Rep. Korea
SO: NATURE. 1990. vol. 347, no. 6288, pp. 58-61
LA: English
ER: M (Marine)
AB: Three decades after the first study of nitrous oxide (N sub(2)O) in the ocean, the marine geochemistry of this compound is of exceptional interest for two reasons: first, the need to understand the role of N sub(2)O in both nitrification and denitrification in the sea, and second, the importance of N sub(2)O in the stratospheric ozone cycle and as a greenhouse trace gas that, molecule for molecule, is 200 times more effective than carbon dioxide. Related questions concern the role of the ocean as a source or sink of tropospheric N sub(2)O and the processes responsible for its production and consumption in the sea. Our approach to these problems is one that has been successful in studies of H sub(2)O geochemistry and sources of atmospheric CO (ref. 9): the simultaneous study of two isotopic components of a molecule, here the super(15)N/ super(14)N and super(18)O/ super(16)O ratios.
AN: 2324362
1299 of 1521
TI: Role of sub-micrometre particles in the ocean.
AU: Isao,-K.; Hara,-S.; Terauchi,-K.; Kogure,-K.
AF: Ocean Res. Inst., Univ. Tokyo, Nakano, Tokyo 164, Japan
SO: NATURE. 1990. vol. 345, no. 6272, pp. 242-244
LA: English
ER: M (Marine)
AB: Particulate matter plays an important part in biogeochemical cycles in the ocean; as particles settle out of the water column, they carry with them carbon and other adsorbed chemicals. Here the authors present results from epifluorescence microscopy and from particle counting which have allowed us to determine the vertical distribution of submicrometre particles (size range 0.38-1 mu m). We find that > 95% of these particles are non-living and occur in the upper layers of the ocean (50 m) in concentrations of the order of 10 million per millilitre. Many of the non-living particles seem to be fragile and flexible, and seem to have a high water content and to be composed largely of organic material. The size distribution of these submicrometre particles leads the authors to conclude that a significant portion (at least 10%) of "dissolved" organic material may in fact be in the form of these small particles, as suggested by Sharp.
AN: 2313377
1300 of 1521
TI: Limnology of four groundwater-fed saline lakes in south-western Australia.
AU: Burke,-C.M.; Knott,-B.
AF: Dep. Zool., Univ. Western Australia, Nedlands, W.A. 6009, Australia
SO: AUST.-J.-MAR.-FRESHWAT.-RES. 1989. vol. 40, no. 1, pp. 55-68
LA: English
ER: B (Brackish)
AB: Salinity, temperature, dissolved oxygen (DO), pH and total alkalinity (TA) were measured in four saline lakes of Yalgorup National Park, Western Australia, primarily over an 18-month period, July 1985 to January 1987, but also during 1987 and in 1988. These are shallow (<3 m) ground-water sinks with no surface drainage. Rainfall and hence ground-water inflow to the lakes was highly seasonal and occurred mainly between May and October. Lakes Hayward, North Newnham and South Newnham were consistently hypersaline (e.g. Hayward 61-214 g/L) and Hayward and North Newnham were stratified from autumn to early summer. The bottom layer of water in Hayward was usually supersaturated (to 430%) with respect to DO, because of the photosynthetic activity of the benthic microbial communities (BMC). During spring, extensive growth of the charophyte Lamprothamnium papulosum across the sediments in Lake Pollard increased DO (from c. 140% saturation) and pH (from c. 8 multiplied by 5 to c. 10), but lowered specific TA (from 0 multiplied by 26 to 0 multiplied by 07 meq/L per unit salinity); later removal of the L. papulosum by swans reduced DO to 50% saturation and pH to 7 multiplied by 5, and increased specific TA to 0 multiplied by 15 meq/L per unit salinity.
AN: 2313202
1301 of 1521
TI: Transfer and biogeochemistry of organic matter at the water-sediment interface in a north-western Mediterranean canyon.
AU: Buscail,-R.; Gadel,-F.
AF: Lab. Sedimentol. Geochim. Mar., UA 715 CNRS, Univ. Perpignan, 66025 Perpignan, France
CO: 8. Int. Symp. on Environmental Biogeochemistry, Nancy (France), 14 Sep 1987
SO: RECL.-TRAV.-LAB.-SEDIMENTOL.-GEOCHIM.-MAR.-UNIV.-PERPIGNAN. 1987. vol. 4, 1 p
NT: Summary only.
LA: English
ER: M (Marine)
AB: With reference to the biogeochemical cycles of organic carbon in the marine environment, we study the transfer of organic matter and its deposits from the coastal zone near a river mouth to the base of the northwestern margin of the Gulf of Lion. Five bathymorphologic sites were sampled in the Locaze-Luthiers canyon with a Reineck box-corer. The importance of continental or marine sources is stressed by physico-chemical characteristics of suspended matter collected near the bottom by sediment traps.
AN: 2309157
1302 of 1521
TI: Role of heterotrophic bacteria in regulating ammonium utilization, new production and CO sub(2) cycling.
AU: Keil,-R.G.; Kirchman,-D.L.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
CA: Marine Technology Soc., Washington, DC (USA)
IEEE Ocean Engineering Soc., New York, NY (USA)
CO: Oceans '89, Seattle, WA (USA), 18-21 Sep 1989
SO: OCEANS-'-89:-THE-GLOBAL-OCEAN.-VOLUME-1:-FISHERIES,-GLOBAL-OCEAN-STUDIES,-MARINE-POLICY-AND-EDUCATION,-OCEANOGRAPHIC-STUDIES. 1989. p. 292
ST: OCEANS-'-89.
NT: Summary only.
RN: IEEE-89CH2780-5 (IEEE89CH27805)
LA: English
ER: M (Marine)
AB: Ammonium cycling partly determines nitrate utilization by phytoplankton, new production, and indirectly the exchange of CO sub(2) between the atmosphere and the oceans. The role heterotrophic bacteria play in ammonium cycling is unclear. Investigations in the subarctic Pacific and the midcontinental Atlantic shelf indicate that heterotrophic bacteria consume or regenerate ammonium in response to the supply of dissolved free amino acids. Results of whole water incubations with super(15)NH sub(4) super(+) indicate that bacteria can consume similar to 30% of the ammonium taken up in subarctic Pacific waters. Additional experiments using super(15)NH sub(4) super(+) tracers show that amino acid additions (0.3-1.0 mu M) inhibit uptake of ammonium by bacteria. In 0.8 mu m size fractions dominated by heterotrophic bacteria, bacteria regenerated ammonium only when amino acid supply met or exceeded bacterial nitrogen demand. In coastal mid-Atlantic waters, amino acid additions (1.0 mu M) have been shown to inhibit uptake of super(15)N-nitrate by phytoplankton.
AN: 2308642
1303 of 1521
TI: Erosion and sediment yield research -- some recent perspectives.
AU: Walling,-D.E.
AF: Dep. Geogr., Univ. Exeter, Exeter EX4 4RJ, UK
SO: J.-HYDROL.-AMST.. 1988. vol. 100, no. 1-3, pp. 113-141
LA: English
AB: Recent assessments of both the on-farm and off-farm costs of soils loss and sedimentation have emphasized the relevance of research in the field of erosion and sedimentation and this has been further underscored by an increasing awareness of the importance of sediment-associated transport in the movement of contaminants through terrestrial and aquatic ecosystems. In response to these challenges, research has expanded and several new foci of interest can be identified. This review considers three which are seen to be of particular significance.
AN: 2308465
1304 of 1521
TI: Phosphorus budget in an atoll lagoon.
AU: Charpy,-L.; Charpy-Roubaud,-C.J.
AF: ORSTOM Tahiti, P.O. Box 529, Papeete, French Polynesia
CO: 6. Int. Coral Reef Symp., Townsville, Qld. (Australia), 8-12 Aug 1988
SO: PROCEEDINGS-OF-THE-SIXTH-INTERNATIONAL-CORAL-REEF-SYMPOSIUM,-TOWNSVILLE,-AUSTRALIA,-8th-12th-AUGUST-1988.-VOLUME-2:-CONTRIBUTED-PAPERS-MINI-SYMPOSIUM-1-TO-10-14. Choat,-J.H.;Barnes,-D.;Borowitzka,-M.A.;Coll,-J.C.;Davies,-P.J.;Flood,-P.;Hatcher,-B.G.;et-al.-eds.. 1988. pp. 547-550
LA: English
ER: M (Marine)
AB: The different states of phosphorus (mineral, organic, dissolved and particulate) were studied between 1982 and 1987 in the oceanic and lagoon waters and sediment pore waters of the atoll of Tikehau. Fluxes associated with the different forms of phosphorus were measured or estimated. The percentages of phosphorus forms in the lagoon are 58% for the dissolved organic (DOP), 23% for the phosphates (PO sub(4)) and 18% for the particulate organic (POP). Living POP is composed by 28% of phytoplankton, 20% of heterotrophs < 5 mu m, 26% of heterotrophs 5 mu m-35 mu m and 26% of zooplankton (35 mu m - 2000 mu m). Phosphate flux from sediment give all the phosphorus required by phytobenthic production. Detritus probably come from reef production. POP exportation from the lagoon represents only 2.5% of phytoplankton production.
AN: 2304638
1305 of 1521
TI: Nitrogen fixation by epilithic periphyton in small arctic lakes in response to experimental nitrogen and phosphorus fertilization.
AU: Bergmann,-M.A.; Welch,-H.E.
AF: Dep. Fish. Oceans, 501 University Crescent, Winnipeg, Man. R3T 2N6, Canada
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1990. vol. 47, no. 8, pp. 1545-1550
NT: Incl. bibliogr.: 22 ref.
LA: English
ER: F (Freshwater)
AB: Epilithic periphyton played a moderate role in the nitrogen budget small arctic lakes located at Saqvaqjuac, N.W.T. The acetylene reduction technique used to estimate nitrogen fixation indicated that periphyton in 0-2 m water depth were capable of fixing up to 0.86 mg N m super(-2) h during the period of active nitrogen fixation from July to September 1981. Far Lake was fertilized with phosphorus for 3 yr and had a higher rate of fixation than did a P- and N-fertilized lake or a control lake, in agreement with similar studies on temperate and subarctic lakes. A numerical model based on incoming light was used to predict the amount of nitrogen fixed in each study lake throughout the season.
AN: 2304390
1306 of 1521
TI: Some characteristic features and regularities of sedimentogenesis in the northwestern part of the Black Sea (composition and distribution of suspended matter).
OT: Nekotorye osobennosti i zakonomernosti sedimentogeneza v severo-zapadnoj chasti Chernogo morya (veshchestvennyj sostav i raspredelenie vzvesi)
AU: Khrustalev,-Yu.P.; Chernousov,-S.Ya.; Denisov,-V.I.
AF: Gos. Univ. Rostov, USSR
SO: OKEANOLOGIYA-OCEANOLOGY. 1990. vol. 30, no. 2, pp. 288-294
LA: Russian
ER: M (Marine)
AB: Based on the results of expeditional studies conducted in 1979-1985 regularities of influx, distribution and accumulation of particulate suspended matter are analysed. Major types of suspensions are distinguished and patterns of their distribution by seasons are revealed. Solid river discharge, water dynamics and plankton abundance are identified as decisive factors governing seasonality in the distribution of suspended matter concentrations.
AN: 2303624
1307 of 1521
TI: Detritus in coral reef ecosystems: Fluxes and fates.
AU: Alongi,-D.M.
AF: Australian Inst. Mar. Sci., P.M.B. No. 3, Townsville, M.C., Qld. 4810, Australia
CO: 6. Int. Coral Reef Symp., Townsville (Australia), 8-12 Aug 1988
SO: PROCEEDINGS-OF-THE-SIXTH-INTERNATIONAL-CORAL-REEF-SYMPOSIUM,-TOWNSVILLE,-AUSTRALIA,-8th-12th-AUGUST-1988.-VOLUME-1:-PLENARY-ADDRESSES-AND-STATUS-REVIEWS. Choat,-J.H.;Barnes,-D.;Borowitzka,-M.A.;Coll,-J.C.;Davies,-P.J.;Flood,-P.;Hatcher,-B.G.;Hopley,-D.;et-al.-eds.. 1988. pp. 29-36
NT: Incl. bibliogr.: 74 ref.
LA: English
ER: M (Marine)
AB: Present models of detritus fluxes on coral reefs are too simplistic in ignoring or underestimating the role of microbes, the influence of water-column hydrography on the distribution and abundances of organisms and particulate and dissolved nutrients, and rates of detritus consumption by reef organisms. Biochemical changes in aging reef detritus and the magnitude of biogeochemical cycles on coral reefs are largely unknown, despite their acknowledged importance in detrital recycling in other marine systems. A review of the reef literature indicates that most of the above-cited aspects continue to be ignored. It is plausible that microbes, particularly in subsurface anaerobic sediments, are a sink for carbon in coral reef ecosystems.
AN: 2301962
1308 of 1521
TI: The trophic roles of bacteria in marine ecosystems are complicated by synergistic-consortia and mixotrophic-cometabolism.
AU: McN.-Sieburth,-J.
AF: Grad. Sch. Oceanogr., Univ. Rhode Island, Bay Campus, S. Ferry Rd., Narragansett, RI 02822-1197, USA
CO: 1. Int. Symp. on the Microbial Ecology of the Mediterranean Sea (MEM I), Sorrento (Italy), Jun 1987
SO: ASPECTS-OF-MARINE-MICROBIOLOGY. Jones,-E.B.G.;Miller,-J.D.-eds. 1988. vol. 21, no. 2 pp. 117-128
ST: PROG.-OCEANOGR. vol. 21, no. 2
LA: English
ER: M (Marine)
AB: This paper deals with the following topics. 1. Stable, Stratified Ecosystems: Ideal Habitats for Trophic Studies on Marine Bacteria; 2. Synergistic Consortia; 3. Upper Ocean Processes may be Dependent upon the Consortia in Oxic-Anoxic Microparticulates; 4. Mixotrophic Cometabolism; 5. "Bacterial Growth Rates" and "Trophic Rates", the appropriate use of radioisotopes.
AN: 2301365
1309 of 1521
TI: Mineralization of organic material in coastal eutrophic ecosystems according to available terminal electron acceptors.
AU: Marty,-D.; Bertrand,-J.C.; Caumette,-P.; Bianchi,-A.
AF: Microbiol. Mar., CNRS, ER 223, Campus Luminy, Case 907, 70 Route Leon Lachamp, F-13288 Marseille, Cedex 9, France
CO: 1. Int. Symp. on the Microbial Ecology of the Mediterranean Sea (MEM I), Sorrento (Italy), Jun 1987
SO: ASPECTS-OF-MARINE-MICROBIOLOGY. Jones,-E.B.G.;Miller,-J.D.-eds. 1988. vol. 21, no. 2 pp. 167-176
ST: PROG.-OCEANOGR. vol. 21, no. 2
LA: English
ER: M (Marine)
AB: In aquatic ecosystems, the flux of organic matter to bottom sediments depends on primary productivity at the ocean surface and on water depth. In most coastal and intertidal areas, detrital input to the bottom sediments is appreciable, consequently, the neritic sediments are important sites of mineralization and nutrient regeneration of deposited organic matter. This organic matter can be oxidized via oxidative and/or fermentative processes by transfer of electrons to terminal acceptors. The distribution of sedimentary microbial communities involved in carbon flow depends on the availability of diverse electron acceptors and on the efficiency of the different bacteria employing specific electron acceptors.
AN: 2301151
1310 of 1521
TI: The significance of microalgal blooms for fisheries and for the export of particulate organic carbon in oceans.
AU: Legendre,-L.
AF: Dep. Biol., Univ. Laval, Ste-Foy, Que. G1K 7P4, Canada
SO: J.-PLANKTON-RES. 1990. vol. 12, no. 4, pp. 681-699
LA: English
ER: M (Marine)
AB: Microalgal blooms are rapid increases in biomass, caused by locally enhanced primary production and resulting in abnormally high cell concentrations. Hydrodynamical processes may control blooms through the agency of irradiance and/or nutrients. In the oceans, phytoplankton blooms primarily governed by irradiance include the spring outburst, as well as the ice-edge, under-ice, winter, upwelling and estuarine blooms. Those primarily governed by nutrients comprise the tidal, summer, episodic and exceptional blooms. In addition, there are blooms of ice-microalgae. Blooms reflect low recycling, and a large degree of uncoupling between increased primary production and grazing by zooplankton. As a consequence, they often result in high sedimentation of intact cells and faecal pellets. Microalgal blooms provide unique information on the potential fate (and not on the rate) of primary production in marine ecosystems.
AN: 2296767
1311 of 1521
TI: Assessment of inorganic nitrogen fluxes across the sediment-water interface in a tropical lagoon.
AU: Corredor,-J.E.; Morell,-J.M.
AF: Univ. Puerto Rico, Dep. Mar. Sci., Mayaguez 00709, Puerto Rico
SO: ESTUAR.-COAST.-SHELF-SCI. 1989. vol. 28, no. 6, pp. 339-345
LA: English
ER: M (Marine); B (Brackish)
AB: Fluxes of ammonium and nitrate plus nitrite between the sediment and the water column in a shallow tropical lagoon were computed using experimental incubations and theoretical calculations based on observed gradients. Rates computed by the 2 methods compared favourably in the case of ammonium but differed significantly in the case of nitrate plus nitrite. Whereas calculations based on observed gradients predict a net flux of the latter species from the sediment to the water column, experimental incubations show active uptake of nitrate and nitrite by the sediment. It was demonstrated that this uptake is biologically mediated.
AN: 2292684
1312 of 1521
TI: Heavy metals in Narragansett Bay sediments.
AU: Bender,-M.
AF: Off. Mar. Programs, Mar. Resour. Build., URI Narragansett Bay Campus, Narragansett, RI 02882-1197, USA
SO: MARITIMES. 1989. vol. 33, no. 4, pp. 5-7
LA: English
ER: M (Marine)
AB: Anthropogenic additions of heavy metals to Narragansett Bay from domestic and industrial activities have come to exceed the natural sources of heavy metals. This can be seen clearly by the abundance of trace metals in the water, sediments, and animals near population centers, industrial sites, and sewage discharges. The abiological behavior of metals in estuaries is largely governed by their solubility in the presence of oxygen and sulfide. When oxygen is present, as it is in estuarine waters, manganese and iron tend to form precipitates which will cause those metals to be incorporated onto particles and transferred to the sediment. When sulfide is present, as it is in estuarine sediments rich in organic debris, it will combine with metals such as copper, cadmium, zinc, and lead. The metal sulfides that form are highly insoluble and will tend to be sequestered in the sediments. Pollutant trace metals added to the Bay can, in principal, be assimilated into natural cycles. However, trace metals in the Bay have been raised to such high concentrations by pollution that their abundance far exceeds biological requirements.
AN: 2291934
1313 of 1521
TI: Ascending and descending fluxes of lipid compounds in North Atlantic and North Pacific abyssal waters.
AU: Grimalt,-J.O.; Simoneit,-B.R.T.; Gomez-Belinchon,-J.I.; Fischer,-K.; Dymond,-J.
AF: Dep. Environ. Chem. (CID-CSIC), Jordi Girona 18, 08034-Barcelona, Spain
SO: NATURE. 1990. vol. 345, no. 6271, pp. 147-150
LA: English
ER: M (Marine)
AB: Based on the sediment-trap experiments, the authors show that upward fluxes determine the biogeochemical cycling of some lipids in abyssal waters. Up-to-down flux ratios ranging between 0.19-190% and 15-13,000% have been found for sterols and fatty acids, respectively. The ascending organic material corresponds essentially to zooplankton and crustacean debris, whereas algal patterns dominate in the settling particles. Results indicate that formation of buoyant matter in abyssal waters may act as a selection mechanism by which some lipid components are recycled back to the upper water levels whereas others keep descending towards the bottom. This previously unreported process has implications for the interpretation of the lipid record in oceanic sediments, especially when molecular stratigraphy is used for palaeoenvironmental assessment.
AN: 2290405
1314 of 1521
TI: The behaviour of super(59)Fe in marine microhabitat.
AU: Cai,-Fulong; Chen,-Ying; Xu,-Pi'-an; Qiu,-Manhua
AF: 3rd Inst. Oceanogr., SOA, Xiamen, People's Rep. China
SO: ACTA-OCEANOL.-SIN.-HAIYANG-XUEBAO. 1989. vol. 8, no. 3, pp. 423-429
LA: English
ER: M (Marine)
AB: Under artificial conditions the super(59)Fe morphology in sea water, its concentration in sediment and phytoplankton, its distribution and metabolism in tissue organs of marine animals were studied. The results showed that the morphology of super(59)Fe was in a particulate state in sea water. The adsorption rule of super(59)Fe by three kinds of sediments was similar, and the concentration ability of super(59)Fe by phytoplankton was very strong. Critical concentration organs of super(59)Fe by marine animals were viscera, and gross radioactivity of super(59)Fe was mainly concentrated in protein. The concentration factor of super(59)Fe by DNA was the highest one. After excretion experiment, super(59)Fe of all the tissue organs was not detected. A small part of super(59)Fe remained in the organic acid and protein state. There was a redistribution process in sediment for super(59)Fe.
AN: 2289650
1315 of 1521
TI: Water pollution: Pesticides in aquatic environments. January 1978-December 1989 (a bibliography from Pollution abstracts).
CA: National Technical Information Serv., Springfield, VA (USA)
SO: SPRINGFIELD,-VA-USA-NTIS 1990. 71 pp
NT: NTIS Order No.: PB90-864620/GAR. 135 refs.
LA: English
AB: This bibliography contains citations concerning the physicochemical and biochemical dynamics of pesticides in aquatic environments. The effects of organophosphorus, organochlorine, and arsenical pesticides on marine, surface, and groundwater ecosystems are discussed. Topics include biological fate and transformation of pesticides in waters, sources of release and transport of pesticides, bioaccumulation and metabolism of pesticides by aquatic organisms, ecological concentration and degradability of pesticides in model ecosystems, marine ecology, and guidelines for pesticide registration and pesticide effluents. (This updated bibliography contains 135 citations, 15 of which are new entries to the previous edition). (Supersedes PB89-853733. Prepared in cooperation with Cambridge Scientific Abstracts, Washington, DC.)
AN: 2287315
1316 of 1521
TI: Evidence from carbon isotope measurements for diverse origins of sedimentary hydrocarbons.
AU: Freeman,-K.H.; Hayes,-J.M.; Trendel,-J.-M.; Albrecht,-P.
AF: Biogeochem. Lab., Dep. Chem. and Geol., Geol. Build., Indiana Univ., Bloomington, IN 47405-5101, USA
SO: NATURE. 1990. vol. 343, no. 6255, pp. 254-256
LA: English
AB: The organic matter found in sedimentary rocks must derive from many sources; not only from ancient primary producers but also from consumers and secondary producers. In all of these organisms, isotope effects can affect the abundance and distribution of super(13)C in metabolites. Here, by using an improved form of a previously described technique in which the effluent of a gas chromatograph is continuously analysed isotopically, we report evidence of the diverse origins of sedimentary organic matter. The record of super(13)C abundances in sedimentary carbonate and total organic carbon can be interpreted in terms of variations in the global carbon cycle. Our results demonstrate, however, that isotope variations within sedimentary organic mixtures substantially exceed those observed between samples of total organic carbon. Resolution of isotope variations at the molecular level offers a new and convenient means of refining views both of localized palaeoenvironments and of control mechanisms within the global carbon cycle.
AN: 2286364
1317 of 1521
TI: Peatland ice/water quality.
AU: Kadlec,-R.H.; Li,-Xiang-Ming
AF: Dep. Chem. Eng., Univ. Michigan, Ann Arbor, MI 48109-2136, USA
SO: WETLANDS. 1990. vol. 10, no. 1, pp. 93-106
LA: English
ER: F (Freshwater)
AB: Freezing of the shallow water in a northern peatland caused downward movement of solutes. Nutrients and tracers were rejected from overlying water, with lesser effects in a wetland receiving treated municipal wastewater. Concentration profiles within the ice are controlled by starting concentrations and rate of freezing. High concentrations near the ice top are caused by initial fast freezing, but solute accumulations near the soil surface can cause high concentrations at the lower ice surface also. Chloride partitions most strongly; nutrients or biologically active species partition less strongly. Complex mass and energy balance calculations can provide reasonable estimates of chloride concentrations, but sufficient field data would rarely be available to execute detailed predictions for other ions. Processes involving ice are important in the reallocation of dissolved species within peatlands. Ice formation can cleanse a closed-basin wetland once each year.
AN: 2285855
1318 of 1521
TI: Methods of studies of aquatic microorganisms.
OT: Metody izucheniya vodnykh mikroorganizmov
AU: Kuznetsov,-S.I.; Dubinina,-G.A.
SO: MOSKVA-USSR-NAUKA 1989. 288 pp
NT: Incl. bibliogr.: 426 ref.
LA: Russian
AB: The book falls into 3 parts dealing with: 1) traditional and new methods of the "in vivo" and "in vitro" studies of aquatic microorganisms; 2) cultivation and counting of major groups of microorganisms participating in C, N, S, Fe and Mn cycles in water bodies and 3) estimation of intensity of microbiological processes.
AN: 2285680
1319 of 1521
TI: Coagulation on bubbles allows microbial respiration of oceanic dissolved organic carbon.
AU: Kepkay,-P.E.; Johnson,-B.D.
AF: Biol. Oceanogr. Div., Dep. Fish. and Oceans, Bedford Inst. Oceanogr., Dartmouth, N.S. B2Y 4A2, Canada
SO: NATURE. 1989. vol. 338, no. 6210, pp. 63-65
LA: English
ER: M (Marine)
AB: Dissolved organic carbon in sea water (DOC) is one of the chief reservoirs of reactive organic carbon on the planet. To determine the rate at which this carbon breaks down, a long standing paradox must be solved. DOC appears to be remarkably unreactive, yet it must be reactive to maintain the mass balance between organic carbon in the ocean and CO sub(2) in the atmosphere. It is shown that the coagulation of colloidal DOC on bubble surfaces initiates the rapid microbial respiration of carbon which would otherwise be less accessible to the biota. This coupling of respiration to surface coagulation as a physical means of regenerating a substantial fraction (5-15%) of oceanic DOC could be a key factor in the mechanism required to recycle a recalcitrant reservoir of carbon back to CO sub(2).
AN: 2284651
1320 of 1521
TI: Water filtration by dissipative beaches.
AU: McLachlan,-A.
AF: Oregon Inst. Mar. Biol., Univ. Oregon, Charleston, SC 97420, USA
SO: LIMNOL.-OCEANOGR. 1989. vol. 34, no. 4, pp. 774-780
LA: English
ER: M (Marine)
AB: Dissipative or low-gradient beaches are expected to filter low volumes of seawater. This idea was tested on the Oregon coast on two high-energy dissipative beaches with medium and fine sand and found to be correct, filtered volumes being 0.1-7 m super(3)/m/d. Input was mainly due to tidal effects as most wave energy was dissipated in the surf zone. During a very high-energy event on a high tide, however, filtered volume increased by an order of magnitude as a consequence of increased wave input.
AN: 2283494
1321 of 1521
TI: Kinetics of dissolution of Antarctic diatom frustules and the biogeochemical cycle of silicon in the Southern Ocean.
AU: Treguer,-P.; Kamatani,-A.; Gueneley,-S.; Queguiner,-B.
AF: Lab. Chim. Ecosyst. Mar., Inst. Etud. Mar., Univ. Bretagne Occidentale, F-29287 Brest-Cedex, France
SO: POLAR-BIOL. 1989. vol. 9, no. 6, pp. 397-403
NT: 47 ref.
LA: English
ER: M (Marine)
AB: The objectives of this work are: 1) measuring the dissolution rates of biogenic silica for specific and natural assemblages of Antarctic diatoms, at conditions prevailing in Antarctic surface waters during summer; 2) simulating the fate of the biogenic silica particles settling down through the cold and turbulent waters of the Circumpolar Current.
AN: 2279767
1322 of 1521
TI: Annual cycles and budget of nutrients in Berre Lagoon (Mediterranean Sea, France).
AU: Arfri,-R.
AF: Cent. Oceanol. Marseille, (UA 41), Fac. Sci. Luminy, Marseille, France
SO: INT.-REV.-GESAMT.-HYDROBIOL. 1989. vol. 74, no. 1, pp. 29-49
LA: English
ER: B (Brackish)
AB: The annual cycles of nutrients in the Etang de Berre were studied in 1985. An estimation is proposed for a nutrient budget. Seasonal variability is important, and a biological control of nutrient availability (locally remineralized products) results in a hydrologically controlled system (nutrients carried by continental waters) which produces the very high microalgal biomass in the lagoon. The seasonal halocline brings the euphotic layer very close to the remineralization site. Nutrients are then constantly available to the phytoplankton.
AN: 2274966
1323 of 1521
TI: Microbial utilization of naturally occurring hydrocarbons at the Guaymas Basin hydrothermal vent site.
AU: Bazylinski,-D.A.; Wirsen,-C.O.; Jannasch,-H.W.
AF: Biol. Dep., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1989. vol. 55, no. 11, pp. 2832-2836
LA: English
ER: M (Marine)
AB: The Guaymas Basin (Gulf of California; depth, 2,000 m) is a site of hydrothermal activity in which petroliferous material is formed by thermal alteration of deposited planktonic and terrestrial organic matter. The authors investigated certain components of these naturally occurring hydrocarbons as potential carbon sources for a specific microflora at these deep-sea vent sites. Respiratory conversion of (1- super(14)C)hexadecane and (1(4,5,8)- super(14)C)naphthalene to super(14)CO sub(2) was observed at 4 degree C and 25 degree C, and some was observed at 55 degree C, but none was observed at 80 degree C. Bacterial isolates were capable of growing on both substrates as the sole carbon source. All isolates were aerobic and mesophilic with respect to growth on hydrocarbons but also grew at low temperatures (4 to 5 degree C). These results correlate well with previous geochemical analyses, indicating microbial hydrocarbon degradation, and show that at least some of the thermally produced hydrocarbons at Guaymas Basin are significant carbon sources to vent microbiota.
AN: 2271250
1324 of 1521
TI: Sulfur-containing amino acids as precursors of thiols in anoxic coastal sediments.
AU: Kiene,-R.P.; Malloy,-K.D.; Taylor,-B.F.
AF: Rosenstiel Sch. Mar. and Atmos. Sci., Univ. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149-1098, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1990. vol. 56, no. 1, pp. 156-161
LA: English
ER: M (Marine)
AB: Sulfur-containing amino acids were examined as precursors for thiols in anoxic coastal sediments. Substrates (10 to 100 mu M) were anaerobically incubated with sediment slurries; thiols were assayed as isoindole derivatives by high-performance liquid chromatography; and microbial transformations of thiols, in contrast to their chemical binding by sediment particles, were identified by inhibition with a mixture of chloramphenicol and tetracycline. Methionine and homocysteine were transformed to methanethiol and 3-mercaptopropionate (3-MPA); methionine stimulated mainly methanethiol production, whereas homocysteine generated more 3-MPA than methanethiol. 2-Keto-4-methiolbutyrate yielded results similar to those with methionine, indicating that demethiolation yields methanethiol at the keto-acid level. Glutathione gave rise to cysteine, which was further transformed to 3-mercaptopyruvate and thence to mercaptoacetate and mercaptoethanol. Mercaptoethanol was oxidized to mercaptoacetate, which was biologically consumed.
AN: 2271162
1325 of 1521
TI: Marine microbiology: A need for deep-sea diving?.
AU: Jannasch,-H.W.
AF: Woods Hole Oceanogr. Inst., Woods Hole, MA 02543, USA
SO: MAR.-TECHNOL.-SOC.-J. 1990. vol. 24, no. 2, pp. 38-41
NT: Special issue: A deepest ocean presence.
LA: English
ER: M (Marine)
AB: Studies in deep-sea microbiology are an essential part of global biogeochemistry and of biological oceanography in particular. Discovering the heterogeneity of microbial populations and their activities on the deep-sea floor was not possible without the capability of visual surveying and sample collecting during manned diving operations. This lack of uniformity not only refers to hydrothermal vents and cold seeps but also to the discontinuous accumulations of organic deposits in seafloor depressions at a large range of scales and the resulting formation of nutrient enriched anoxic pockets. Free-vehicles have aided in this work. The rapid developments of ROV capabilities promise wide geographical spread of microbial deep-sea studies. In planning to extend our diving operations to the oceans' maximum depths, the simultaneous development and use of all of these approaches will be essential, and it is greatly hoped that economic consideration will not force us into making premature choices.
AN: 2270920
1326 of 1521
TI: Biological research needs for submersible access to the greatest ocean depths.
AU: Robison,-B.H.; Wishner,-K.
AF: Monterey Bay Aquar. Res. Inst., Pacific Grove, CA, USA
SO: MAR.-TECHNOL.-SOC.-J. 1990. vol. 24, no. 2, pp. 34-37
NT: Special issue: A deepest ocean presence.
LA: English
ER: M (Marine)
AB: Despite the availability of DSV Alvin to the oceanographic community, the great majority of the living space in the deep sea is not accessible to researchers. Based on what we have learned from submersible work within Alvin's 4 km depth range, conventional sampling methods such as trawls and dredges give a restricted and biased view of both pelagic and benthic ecology. This paper presents a preliminary outline of biological research topics to be conducted by submersibles in deep water. In the deep water column we need to assess the identities, abundances, and small-scale distribution patterns of the constituent midwater fauna. At the benthic boundary layer we need to study biogeochemical cycling and the energetic coupling between pelagic and benthic communities. On the deep seafloor we need to investigate the variability of faunal distributions and abundances, in steady state and in response to a variety of perturbations. In all of these deep habitats we need to study the dynamic, functional aspects of ecology that can only be examined through direct observations and sampling.
AN: 2268895
1327 of 1521
TI: Dynamics of mineral phosphate in water column in the East Pacific.
OT: Dinamika mineral'nogo fosfata v tolshche vody vostochnoj chasti Tikhogo okeana
AU: Sorokin,-Yu.I.
AF: Yuzhn. Otd. IOAN SSSR, Gelendzhik, USSR
SO: OKEANOLOGIYA-OCEANOLOGY-MOSC.. 1990. vol. 30, no. 1, pp. 70-77
LA: Russian
ER: M (Marine)
AB: The total intensity of PO sub(4)-P consumption by microplankton (A sub(t)) is shown to reach maximum values (150-280 ng/l/h) in upwelling zone and in the zone of phytoplankton bloom caused by this upwelling at the Peruvian section. In other areas of this section in surface water layers it constituted 40-80 ng/l. In waters of lower productivity of Central American and Californian sections it decreased to 20-40 ng/l. At the vertical profile A sub(t) maxima were recorded at upper boundary of thermocline. In the zones of phytoplankton bloom 60-80% of total PO sub(4)-P consumption is accounted for phytoplankton. In the zones of enhanced bacteria number phytoplankton share in PO sub(4)-P total consumption decreased to 20-40%. Data are presented to show absence of correlation between PO sub(4)-P concentration in water and productivity level. It is emphasized that the above parameters of PO sub(4)-P dynamics can be used to obtain characteristics of functional state and succession phase of development of marine plankton communities.
AN: 2267823
1328 of 1521
TI: Particulate organic carbon of the south-eastern portion of the South China Sea.
AU: Ichikawa,-T.; Law,-A.T.
AF: Dep. Biol., Fac. Sci., Kagoshima Univ., Korimoto, Kagoshima 890, Japan
SO: EKSPEDISI-MATAHARI-'-87:-A-STUDY-ON-THE-OFFSHORE-WATERS-OF-THE-MALAYSIAN-EEZ. Mohsin,-A.K.M.;Mohamed,-M.I.H.-eds. 1988. no. 8 pp. 37-42
ST: OCCAS.-PUBL.-FAC.-FISH.-MAR.-SCI.-UNIV.-PERTANIAN-MALAYS. no. 8
LA: English
ER: M (Marine)
AB: Particulate organic carbon in sea water was measured in samples collected in the waters off West Malaysia (Borneo) during the cruise of R.V. Kagoshima-Maru (Matahari Expedition '87). The carbon concentrations at 16 stations changed from 54 to 142 mu gC/l. The integrated amount of particulate organic carbon in the water column (0-50 m) at each station was in the range 3.7 to 6.0 gC/m super(2).
AN: 2266559
1329 of 1521
TI: The effect of iron nutrition on photosynthesis and nitrogen fixation in cultures of Trichodesmium (Cyanophyceae).
AU: Rueter,-J.G.; Ohki,-K.; Fujita,-Y.
AF: Dep. Biol., Portland State Univ., Portland, OR 97207-0751, USA
SO: J.-PHYCOL. 1990. vol. 26, no. 1, pp. 30-35
LA: English
ER: M (Marine)
AB: Cultures of Trichodesmium NIBB 1067 were grown in the synthetic medium AQUIL with a range of iron added from none to 5 x 10 super(-7) M Fe for 15 days. Chlorophyll-a cell counts, and total cell volume were two or three times higher in medium with 10 super(-7) M Fe than with no added Fe. Oxygen production rate per chlorophyll-a was over 60% higher with higher iron. Increased iron stimulated photosynthesis at all irradiances from about 12-250 mu E/m super(2)/s. Nitrogen fixation rate, estimated from acetylene reduction, for 10 super(-7) and 10 super(-8) M Fe cultures was approximately twice that of the cultures with no added Fe. The range of rates of O sub(2) production and N sub(2) fixation in cultures at the iron concentrations used were similar to the rates from natural samples of Trichodesmium) from both the Atlantic and the Pacific oceans. This similarity may allow this clone to be used, with some caution, for future physiological ecology studies. This study demonstrates the importance of iron to photosynthesis and nitrogen fixation and suggests that Trichodesmium plays a central role in the biogeochemical cycles of iron, carbon and nitrogen.
AN: 2261352
1330 of 1521
TI: Dimethylsulfide and the alga Phaeocystis pouchetii in Antarctic coastal waters.
AU: Gibson,-J.A.E.; Garrick,-R.C.; Burton,-H.R.; McTaggart,-A.R.
AF: Australian Antarctic Div., Channel Highw., Kingston, Tas. 7050, Australia
SO: MAR.-BIOL. 1990. vol. 104, no. 2, pp. 339-346
NT: 43 ref.
LA: English
ER: M (Marine)
AB: The concentrations of dimethylsulfide (DMS), dimethyl-sulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) were measured in water collected from the Southern Ocean 10 km offshore from Davis Station, Antarctica, during the period May 1987 to Jan 1988, inclusive. During winter and spring, when the sea-ice was up to 1.9 m thick, DMS, DMSP and DMSO concentrations were low (0.2 to 1.5 nM), as were phytoplankton numbers. The maximum concentration of the sulfur compounds generally occurred in top 10 m of the water column. DMS levels rose dramatically from early Dec onwards, reaching a peak of 290 nM at a depth of 15 m in Jan. This concentration is higher than reported elsewhere in the ocean. These high concentrations occurred at the same time as a bloom of the alga Phaeocystis pouchetii . A significant correlation occurred between DMS concentration and cell numbers of the alga.
AN: 2260449
1331 of 1521
TI: What happens to zooplankton faecal pellets? Implications for material flux.
AU: Lampitt,-R.S.; Noji,-T.; Bodungen,-B.-von
AF: Inst. Oceanogr. Sci., Deacon Lab., Wormley, Godalming, Surrey GU8 5UB, UK
SO: MAR.-BIOL. 1990. vol. 104, no. 1, pp. 15-23
NT: 51 ref.
LA: English
ER: M (Marine)
AB: In 1987/1988 we carried out experiments using adult copepods of mixed species but dominated by Centropages hamatus collected in Kiel Bight (FRG). We have demonstrated that copepods can be highly adept at breaking up their own pellets while ingesting only a small proportion, a behaviour we define as "coprorhexy". The microbiota is probably unable to cause significant modification to faecal pellets before they are fragmented within a few hours of their production. Thereafter, microbial remineralisation will become important. Many of the "difficult" field data can be readily explained if the process of coprorhexy is taken into account and, indeed, breakage of large particles by crustacean zooplankton may be an important process in modifying material transport in the ocean. Copepods appear to perform coprorhexy by removing the peritrophic membrane with its attached bacterial flora and this may then be ingested.
AN: 2260301
1332 of 1521
TI: Extracellular organic carbon (EOC) in the genus Carpophyllum (Phaeophyceae): Diel release patterns and EOC lability.
AU: Soendergaard,-M.
AF: Inst. Life Sci. and Chem., Roskilde Univ., P.O. Box 260, DK-4000 Roskilde, Denmark
SO: MAR.-BIOL. 1990. vol. 104, no. 1, pp. 143-151
NT: 37 ref.
LA: English
ER: M (Marine)
AB: Release of extracellular organic carbon (EOC) by the four species of the brown algal genus Carpophyllum was investigated in light:dark incubations of 30 to 40 h duration using a super(14)C-method. Plants were collected during 1986 in the Hauraki Gulf area, Auckland, New Zealand. In C. maschalocarpum and C. plumosum rather low release rates in light (2 to 5% of the photosynthetic rates) were followed by high release rates after 4 to 5 h in darkness (10 to 15% of previous photosynthetic rates). The opposite pattern, with high release in light and low in darkness, was found in experiments with C. angustifolium and C. flexuosum . The pattern with substantially higher release in dark than in light is observed for the first time. EOC products were dominated by small molecules (< 1000 daltons) in all four species and both in light and darkness.
AN: 2260142
1333 of 1521
TI: Interaction between supply of nutrients, primary production, sedimentation and oxygen consumption in SE Kattegat.
AU: Rydberg,-L.; Edler,-L.; Floderus,-S.; Graneli,-W.
AF: Inst. Oceanogr., Box 4038, S-400 40 Goeteborg, Sweden
SO: AMBIO. 1990. vol. 19, no. 3, pp. 134-141
NT: Special issue: Marine eutrophication.
LA: English
ER: M (Marine)
AB: Intensive measurements of nutrient fluxes, carbon and nitrogen assimilation, sedimentation and oxygen consumption within the SE Kattegat are used in an effort to follow the coupling between increasing nutrient supply and decreasing deep-water oxygen concentrations. The investigated area is a part of the strongly stratified Baltic estuary, with a hampered deep-water exchange and a large supply of nitrogen from nearby anthropogenic sources. Measurements were undertaken during 1981-1988. The results are discussed, mainly in terms of annual or seasonal mean values. The average primary production, 11.4 mol C/m super(2) was surprisingly well correlated with the uptake of inorganic nitrogen, which averaged 1.68 mol N/m super(2) (11.1 mol C/m super(2), using the Redfield ratio). The oxygen consumption (deep water and benthic) which averaged 20 mol O sub(2)/m super(2)/d, was well correlated both with the measured nitrate uptake and with the external supply of nitrate to the surface water.
AN: 2257934
1334 of 1521
TI: Nutrient dynamics of the Baltic Sea.
AU: Wulff,-F.; Stigebrandt,-A.; Rahm,-L.
AF: Askoe Lab., Univ. Stockholm, S-106 91 Stockholm, Sweden
SO: AMBIO. 1990. vol. 19, no. 3, pp. 126-133
NT: Special issue: Marine eutrophication.
LA: English
ER: M (Marine)
AB: A prerequisite for understanding the large-scale eutrophication of the Baltic Sea is an understanding of the factors responsible for regional and long-term variations of nutrients. This article summarizes recent studies on the changes in overall total amounts and the distribution pattern of nutrients. The total amounts of phosphorus and nitrogen have increased over the last few decades. On the other hand, silicate levels have been decreasing, indicating a higher net primary production and sedimentation of diatoms. A series of models has been used to test our present understanding of the critical processes controlling nutrient and oxygen conditions. It is shown that a few morphometric factors are essential, like shallow sill depth at the entrance of the estuarine-like sea and shallow mean depth. It is also shown that phosphorus, nitrogen and silicate differ in terms of residence times and their response to external loading.
AN: 2257815
1335 of 1521
TI: (Transformation of organic and biogenic matters under anthropogenic eutrophication of lakes.).
OT: Transformatsiya organicheskogo i biogennykh veshchestv pri antropogennom ehvtrofirovanii ozer
AU: Drabkova,-V.G.; Stravinskaya,-E.A.-(eds.)
SO: LENINGRAD-USSR-NAUKA 1989. 270 pp
NT: Incl. bibliogr.: 254 ref.
LA: Russian
ER: F (Freshwater)
AB: The intensity of productional and destructional processes as dependent on arrival and transformation of biogenic matters is estimated with reference to the lakes of Latgal upland (eastern Latvia) subjected to man-induced effects. The arrival of P and N from bottom sediments is shown to be an important factor responsible for the content of these substances in water. The relationship between inner and outer biogenic load on the lakes is presented. The intensity of P consumption and regeneration by biological communities of different trophic levels in water and lake bottom sediments is considered.
AN: 2255241
1336 of 1521
TI: Optical modeling of the upper ocean in relation to its biogenous matter content (case 1 water).
AU: Morel,-A.
AF: Lab. Phys. et Chim. Mar., Univ. Pierre et Marie Curie, Villefranche-Sur-Mer, France
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1988. vol. 93, no. C9, pp. 10749-768
LA: English
ER: M (Marine)
AB: The aim of the present study is to review and tentatively to interpret the optical behavior of oceanic case 1 waters, those waters for which phytoplankton and their derivative play a predominant role in determining their optical properties. Chlorophyll-like pigment concentration is used as the index to quantify the algal material (living and detrital), and statistical relationships between this index and the depth of the euphotic layer, the spectral values of the attenuation coefficient for downwelling irradiance, or the scattering coefficient are investigated. On the basis of these statistical relationships a pigment-dependent optical model is developed. Other geophysical or geochemical applications are derived which concern the heating rate due to penetrating visible radiations or the rate of energy storage due to photosynthesis.
AN: 2239550
1337 of 1521
TI: (Tin and organotins in the marine environment: Biogeochemistry and ecotoxicology.).
OT: L'etain et les organoetains en milieu marin: Biogeochimie et ecotoxicologie
AU: Alzieu,-C.
AF: IFREMER, Cent. Nantes, BP 1049, 44037 Nantes Cedex, France
SO: RAPP.-SCI.-TECH.-IFREMER. PLOUZANE-FRANCE-IFREMER,-CENT.-BREST,-SERVICE-DOCUMENTATION-and-PUBLICATION 1989. no. 17, 93 pp
LA: French
ER: M (Marine)
AB: This report synthesizes the knowledge on the biogeochemical cycle, bioconcentration processes and ecotoxicity of tin and organotins in the marine environment. Concentrations levels, biomethylation mechanisms and exchanges between sediments and water are assessed. Emphasis is given on tributyltin sublethal effects, toxicity mechanisms and no effect levels for the most sensitive organisms. Regulations on the use of organotins as antifoulants in paints are examined. Conclusions and recommendations for environmental management and research are given.
AN: 2232000
1338 of 1521
TI: (Cadmium in marine environment.).
OT: Le cadmium en milieu marin
AU: Cossa,-D.; Lassus,-P.
AF: IFREMER, Cent. Nantes, Rue de l'Ile d'Yeu, BP 1049, 44037 Nantes Cedex 01, France
SO: RAPP.-SCI.-TECH.-IFREMER. PLOUZANE-FRANCE-IFREMER,-CENT.-BREST,-SERVICE-DOCUMENTATION-and-PUBLICATION 1989. no. 16, 112 pp
LA: French
ER: M (Marine)
AB: This report synthesizes the knowledge on the biogeochemical cycle, bioconcentration processes and ecotoxicity of cadmium in the marine environment. Man induced changes on the cadmium cycle, especially along the French coasts are reviewed. Concentration levels, mechanisms and fluxes between geochemical reservoirs are assessed. Emphasis is given on sublethal effects and toxicity mechanisms. Quality standards used in European Community countries are listed. Conclusions and recommendations for environmental management and research are given.
AN: 2231970
1339 of 1521
TI: Organic matter degradation and nutrient regeneration in Australian freshwaters: 1. Methods for exoenzyme assays in turbid aquatic environments.
AU: Boon,-P.I.
AF: Murray-Darling Freshwater Res. Cent., P.O. Box 921, Albury, N.S.W. 2640, Australia
SO: ARCH.-HYDROBIOL. 1989. vol. 115, no. 3, pp. 339-359
NT: Bibliogr.: 44 ref.
LA: English
ER: F (Freshwater)
AB: A method was developed using p-nitrophenol and p-nitroaniline derivatives to measure exoenzyme activity in turbid waters. Maximum activity occurred at temperatures of 40 degree C or above. The response to variations in pH was complex, with some systems showing no clear optimum but others showing an optimum at either pH of 7.5 or pH 9.0-10.0. Only 25% of the enzyme system-site combinations generated linear Lineweaver-Burke plots, indicating that many exoenzyme systems were active simultaneously in the degradation of organic detritus. The maximum rate of activity occurred with aminopeptidase (up to 107 mu mol/l/d), followed by alkaline phosphatase (up to 42 mu mol/l/d). There was little lipase or alpha -D glucosidase activity in the any water body, except in a highly-eutrophied lagoon. Rates were consistently higher in billabongs than in rivers, and most activity was associated with particles rather than being free in the water column.
AN: 2225377
1340 of 1521
TI: New production and export of organic matter to the deep ocean: Consequences of some recent discoveries.
AU: Legendre,-L.; Gosselin,-M.
AF: Dep. Biol., Univ. Laval, Ste-Foy, Que. G1K 7P4, Canada
SO: LIMNOL.-OCEANOGR. 1989. vol. 34, no. 7, pp. 1374-1380
LA: English
ER: M (Marine)
AB: It is generally accepted that planktonic new production is equivalent to the export of particulate organic matter (POM) to the deep ocean. The difference between new (P sub(N)) and total (P sub(T)) primary production is regenerated production (P sub(R)), which is fueled by nutrients regenerated in surface waters by the heterotrophic food web. New and regenerated production in the euphotic zone can be estimated from the uptake of super(15)N-labeled nitrate (P sub(N)) and that of ammonia and urea (P sub(R)). The ratio of new to total production (P sub(N):P sub(T)), when estimated independently can be used to computer P sub(N) from P sub(T) in cases where the latter has been measured directly (e.g. from photosynthetic assimilation of super(14)C-labeled CO sub(2)).
AN: 2221552
1341 of 1521
TI: Influence of coupling of sorption and photosynthetic processes on trace element cycles in natural waters.
AU: Fuller,-C.C.; Davis,-J.A.
AF: Water Resour. Div., U.S. Geol. Surv., Menlo Park, CA 94025, USA
SO: NATURE. 1989. vol. 340, no. 6228, pp. 52-54
LA: English
ER: F (Freshwater)
AB: We have studied the effect of diurnal cycling of pH on dissolved arsenate in a perennial stream contaminated with arsenic. As expected, a diurnal cycle in arsenate concentration was observed, but surprisingly, the arsenate cycle lags several hours behind the pH cycle. Laboratory experiments show that the lag results from a slow approach to sorption equilibrium. Our observations demonstrate that the coupling of photosynthesis and sorption processes may have an important influence on the cycling of many trace elements and emphasize the importance of understanding sorption kinetics in modelling these processes.
AN: 2220988
1342 of 1521
TI: Upon the role of vegetation in sulfur storage in mangrove soils (Senegal). Preliminary results.
OT: Sur le role de la vegetation dans le stockage du soufre dans les sols de mangrove (Senegal). Resultats preliminaires
AU: Feller,-C.; Trichet,-J.; Fontes,-J.C.; Marius,-C.
AF: ORSTOM, c/o CPB-CNRS, LP 6831, Assoc. Univ. Nancy I, BP 5, 54501 Vandoeuvreles-Nancy Cedex, France
SO: SOIL-BIOL.-BIOCHEM. 1989. vol. 21, no. 7, pp. 947-952
LA: English
ER: B (Brackish)
AB: Plant organs, plant residues at different degrees of decomposition, and the surface soil (0-5 cm) of a Rhizophora mangrove in Saloum Island (Senegal) were analyzed for total C, N, S and amino acid content and for sulfur isotopical composition ( delta super(34)S). These preliminary results emphasize the possible role of vegetation (roots and leaves) on S storage in mangrove soils.
AN: 2220692
1343 of 1521
TI: Aspects of the phosphorus cycle in Hartbeespoort Dam (South Africa). Phosphorus kinetics.
AU: Thornton,-J.A.
AF: City Planner's Dep., Cape Town City Counc., P.O. Box 1694, Cape Town 8000, South Africa
SO: HYDROBIOLOGIA. 1989. vol. 183, no. 2, pp. 87-95
LA: English
ER: F (Freshwater)
AB: The role of biotic processes in a warm, monomictic, hypertrophic African impoundment (Hartbeespoort Dam) is examined using super(32)P radiobioassays. Phosphorus demand is assessed by phosphorus turnover times, alkaline phosphatase activity, cellular phosphorus status and the phosphorus deficiency index. Long turnover times indicative of an enriched system were recorded, ranging from 9 h to 1992 h, with no evidence of phosphorus stress being present. These turnover times support the hypothesis that the phosphorus cycle in Hartbeespoort Dam is dominated by the algal community which is shown to play an important role in phosphorus cycling within the water column. However, hydrological processes remain the driving force in phosphorus seasonality in the lake.
AN: 2216536
1344 of 1521
TI: A model of biogeochemical cycling of phosphorus, nitrogen, oxygen, and sulphur in the ocean: One step toward a global climate model.
AU: Shaffer,-G.
AF: Oceanogr. Inst., Univ. Gothenburg, Gothenburg, Sweden
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1989. vol. 94, no. C2, pp. 1979-2004
LA: English
ER: M (Marine)
AB: A ocean model is developed which, for prescribed physics, deals with interrelationships between chemical distributions, biogeochemical sinks and sources, chemical reactions at redox fronts, and transport across the air-sea and sediment-water interfaces. The model focuses on biogeochemical cycling of phosphorus, nitrogen, oxygen, and sulphur in an ocean forced by river input of nutrients. This is a natural starting point for a global climate model since ocean circulation and biology determine atmospheric CO sub(2) concentrations for a given inventory of inorganic C and oceanic production is controlled mainly by the availability to inorganic P and/or N. A general approach is taken to look at oxic versus anoxic conditions, P versus N limitation of primary production, with or without inorganic removal of phosphate to the sediments. Chemical species considered are PO sub(4) super(3-)-P, NO sub(3) super(-)-N, O sub(2), NH sub(4) super(+)-N and H sub(2)S-S. Results indicate that a change from oxic to weakly anoxic conditions at middepths in a P-limited ocean would lead to strong local denitrification and low nitrate concentrations throughout the water column.
AN: 2215036
1345 of 1521
TI: Vertical fluxes of nitrate associated with salt fingers in the world's oceans.
AU: Hamilton,-J.M.; Lewis,-M.R.; Ruddick,-B.R.
AF: Phys. Chem. Sci., Bedford Inst. Oceanogr., Dartmouth, N.S., Canada
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1989. vol. 94, no. C2, pp. 2137-2145
LA: English
ER: M (Marine)
AB: The primary means by which the oceans serve as a sink for atmospheric carbon dioxide is through the vertical flux of sinking organic carbon derived from primary photosynthetic production in the upper ocean. Its rate of loss to the deep sea, the "new production", is rigorously constrained by the upward flux of the limiting nutrient, nitrate. New production estimates have been made by using velocity microstructure measurements to infer nitrate fluxes, where it is assumed that turbulent production (mixing) balances viscous energy dissipation. However, estimates based on a salt finger convection model lead to nitrate fluxes which are as much as an order of magnitude larger than a turbulent mixing model predicts and agree much better with fluxes inferred from biological uptake measurements and tracer studies. Heat flux estimates are higher by less than a factor of 3. Observations of the "scaled dissipation ratio" Gamma , based on velocity and temperature microstructure, may provide a means of distinguishing between the 2 mixing hypotheses. Where both turbulent production and salt fingering contribute to the mixing this distinction is more difficult, but by using measurements of Gamma the potential error in the vertical flux estimate due to an improper choice of mixing models is greatly reduced.
AN: 2214051
1346 of 1521
TI: Geochemical considerations on trace element distributions in suspended matter and sediments at the river-sea interface, Adige River mouth, northern Adriatic Sea.
AU: Boldrin,-A.; Juracic,-M.; Menegazzo-Vitturi,-L.; Rabitti,-S.; Rampazzo,-G.
AF: Mar. Biol. Inst., CNR, 30122, Venezia, Italy
SO: APPL.-GEOCHEM. 1989. vol. 4, no. 4, pp. 409-421
LA: English
ER: B (Brackish)
AB: The particulate matter at the Adige River mouth has been investigated in order to determine the natural geochemical processes in the estuarine environment, and the anthropogenic influence on the biogeochemical cycling of heavy metals. The determination of suspended matter and sediment physicochemical characteristics (grain size, mineralogy, organic matter content, specific surface area), and of concentrations of major and trace elements in the Adige River mouth in different hydrological conditions, has shown that this mouth acts as a trap for most heavy metals. Moderate anthropogenic influence on Cu, Pb, Cd, and Cr concentrations has been recognised in the Adige River. The environmental fate of these elements is determined by the same natural processes, and therefore accumulation in front of the river mouth occurs.
AN: 2213983
1347 of 1521
TI: Parametrization of nutrient sources and discharge in the ocean.
OT: Parametrizatsiya istochnikov i stokov biogenov v okeane
AU: Ryabchenko,-V.A.
AF: Otd. IOAN AN SSSR, Leningrad, USSR
SO: METEOROL.-GIDROL. 1990. no. 2, pp. 78-87
LA: Russian
ER: M (Marine)
AB: A simple seasonal model of an ecosystem of the upper quasihomogeneous layer of the ocean is constructed and verified with reference to the results of observations available. The sensitivity of the model to representation of poorly-known parameters is investigated and their optimum values are determined. The model is shown to reflect satisfactory the seasonal variability in biological sources and discharge of nutrients and it can be employed in global models describing nutrient distribution in the ocean.
AN: 2209496
1348 of 1521
TI: Comparison of detritus dynamics in two tidal freshwater wetlands.
AU: Findlay,-S.; Howe,-K.; Austin,-H.K.
AF: Inst. Ecosyst. Stud., New York Bot. Gard., Mary Flagler Cary Arbor., Millbrook, NY 12545, USA
SO: ECOLOGY. 1990. vol. 71, no. 1, pp. 288-295
LA: English
ER: F (Freshwater)
AB: The authors have examined the generation and persistence of detritus in two contrasting tidal freshwater wetlands on the Hudson River. These wetlands offer a difference in vegetation, with Tivoli South Bay dominated by a floating-leafed macrophyte (water-chestnut, Trapa natans ) and North Bay a typical Typha marsh. In South Bay, there was a large amount of water-chestnut dry biomass (400 g/m super(2)) available to enter the detritus pool, but there was no increase in the standing stock of benthic organic matter following senescence of water-chestnut. Estimates show that mineralization plus leaching of dissolved material are sufficient to remove much of the detritus. In the Typha) marsh, there is a large amount of detritus generated ( approximately equals 25% of annual primary production) and this material persists as a thick litter layer.
AN: 2207208
1349 of 1521
TI: The influence of different litter bag designs on the breakdown of leaf material in a small mountain stream.
AU: Stewart,-B.A.; Davies,-B.R.
AF: Freshwater Res. Unit, Zool. Dep., Univ. Cape Town, Rondebosch, South Africa
SO: HYDROBIOLOGIA. 1989. vol. 183, no. 2, pp. 173-177
LA: English
ER: F (Freshwater)
AB: Leaf breakdown of two riparian tree species, Cunonia capensis L. and Ilex mitis (L.) Radlk. was investigated in vitro at Window Stream, Table Mountain, using three different designs of litter bag. Breakdown of Cunonia and Ilex in coarse-mesh (5 mm) litter bags was very rapid (respectively 14.79 and 13.93% loss d super(-1)), and was significantly greater than the loss of leaf material of 1% d super(-1) for both species from fine-mesh bags (180 mu m). Differences recorded between fine-mesh and composite-mesh bags (180 mu m mesh with 5 mm mesh top) represented macro-invertebrate ingestion, and at t = 28 d, amounted to 67.57% material loss in Cunonia and 62.58% in Ilex . The losses due to microbial activity and leaching, 31.28% in Cunonia and 29.17% in Ilex were not significantly different. Future leaf breakdown experiments in mountain streams must take cognisance of differential fragmentation losses before inferences can be made as to both invertebrate feeding preferences and biological decomposition of leaves.
AN: 2207157
1350 of 1521
TI: Storage and dynamics of subsurface detritus in a sand-bottomed stream.
AU: Metzler,-G.M.; Smock,-L.A.
AF: Dep. Biol., Virginia Commonwealth Univ., Richmond, VA 23284, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1990. vol. 47, no. 3, pp. 588-594
NT: Incl. bibliogr.: 28 ref.
LA: English
ER: F (Freshwater)
AB: Annual mean storage of buried detritus (0-20 cm depth) in a first-order, sand-bottomed stream was 4.8 kg AFDM/m super(2), approximately one order of magnitude greater than surface storage. Forty percent of the buried detritus was wood > 8 mm; much of the remainder was 1-8 mm particles. Exchange of detritus between surface and shallow sediments occurred throughout the year; exchange between surface and deep sediments occurred only during spates. About 21% of estimated autumnal leaf input to the stream became buried. Given the large quantity of detritus stored in the subsurface, its slow processing rate and the episodic nature of its release from deep storage, the hyporheic area of this stream has an important effect on the stream's carbon spiralling length, energetics, and trophic dynamics.
AN: 2207130
1351 of 1521
TI: Low molecular weight carboxylic acids in the sea. Photooxidative production and biological cycling.
AU: Mopper,-K.
CA: Miami Univ., FL (USA). Rosenstiel Sch. of Marine and Atmospheric Sciences
SO: 1987. 5 pp
NT: NTIS Order No.: AD-A189 748/7/GAR. Contract N00014-85-C-0020.
LA: English
ER: M (Marine)
AB: A large fraction of dissolved organic matter (DOM) in seawater is composed of biologically refractory substances. The authors propose to examine organic acid photo-production in seawater as a tool to evaluate the importance of photofragmentation of biologically refractory organic matter in the sea. Laboratory studies will be integrated with a sea-going program, SOLARS, to establish a broad data base for the spatial and temporal distribution of organic acids in coastal and oceanic waters.
AN: 2203631
1352 of 1521
TI: Biogeochemical cycling of organic matter in acidic environments: Are microbial degradative processes adapted to low pH?.
AU: Benner,-R.; Lewis,-D.L.; Hodson,-R.E.
CA: Environmental Protection Agency, Athens, GA (USA). Environmental Research Lab.
SO: ECOL.-RES.-SER.-U.S.-ENVIRON.-PROT.-AGENCY. 1987. 25 pp
NT: NTIS Order No.: PB87-195392/GAR. Prepared with Georgia Univ., Athens.
RN: EPA/600/D-87/176 (EPA600D87176)
LA: English
ER: F (Freshwater)
AB: The rates of microbial degradation of a variety of dissolved and particulate substrates in water and sediment from the Okefenokee Swamp, Georgia, and Corkscrew Swamp, Florida, are compared. The relationship between pH and rates of biodegradation or organic substrates was determined for natural microbial assemblages and for several bacterial isolates from these environments. Results suggest that microbial degradative processes that rely on extracellular enzymes are depressed at low pHs, whereas the microbial utilization of low-molecular-weight compounds that can be directly transported into cells is not substantially affected by variations in pH from 4 to 8.
AN: 2203310
1353 of 1521
TI: VERTEX: Phytoplankton/iron studies in the Gulf of Alaska.
AU: Martin,-J.H.; Gordon,-R.M.; Fitzwater,-S.; Broenkow,-W.W.
AF: Moss Landing Mar. Lab., Moss Landing, CA 95039, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1989. vol. 36, no. 5A, pp. 649-680
LA: English
ER: M (Marine)
AB: VERTEX studies were performed in the Gulf of Alaska in order to test the hypothesis that iron deficiency was responsible for the phytoplankton's failure to remove major plant nutrients from these waters. In view of the observed Fe distributions and the results of phytoplankton Fe enrichment experiments, it was concluded that Gulf of Alaska atmospheric Fe input rates are sufficient to support moderately high rates of primary productivity; however, not enough Fe is available to support the high growth rates that would lead to normal major nutrient depletion. Enhanced Fe input does occur along the Alaska continental margin, where normal NO sub(3) surface depletion is observed. Coccolithophorids appear to be best able to cope with low Fe conditions; however, they cannot compete with diatoms when Fe is readily available.
AN: 2190336
1354 of 1521
TI: Seasonal oxygen cycles and biological new production in surface waters of the subarctic Pacific Ocean.
AU: Emerson,-S.
AF: Sch. Oceanogr., Univ. Washington, Seattle, WA 98195, USA
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1987. vol. 92, no. C6, pp. 6535-6544
LA: English
ER: M (Marine)
AB: Seasonal cycles of oxygen, temperature and salinity at Ocean Weather Station P in the subarctic Pacific Ocean reveal a regular 4-6% supersaturation of oxygen in the surface waters during the summers of the 10-year period 1969-1978. The main processes causing supersaturation are surface water heating and the net effect of primary production and community respiration. The biological and heating signals are separated using a mixed layer model and estimates for the air-water gas exchange rate speed. Biological new production during the summer (mid-May to mid-August) is estimated to be 100-300 mg C m super(-2)/d.
AN: 2190168
1355 of 1521
TI: Detrital processing in seagrass systems: A review of factors affecting decay rates, remineralization and detritivory.
AU: Harrison,-P.G.
AF: Dep. Bot., Univ. British Columbia, Vancouver, B.C. V6T 2B1, Canada
SO: AQUAT.-BOT. 1989. vol. 35, no. 3-4, pp. 263-288
LA: English
ER: M (Marine)
AB: The literature on three related aspects of the ecological role of seagrass detritus was analysed for clues to the factors that determine the rates of decomposition, the amount of remineralization vs. immobilization of nitrogen and the nutritional value of the detritus to animals. Rates of decomposition (usually < 1% of dry wt./day) are generally low compared with other vascular macrophyte sources of detritus, but are influenced by many variables, e.g., chemical composition and growth state of the plant when decay begins, pre-treatments given the plant material (drying, grinding), methods of incubating (litterbags, enclosed microcosms), and the physical and chemical environment in which decay occurs. Standard techniques are lacking, making comparisons difficult.
AN: 2190166
1356 of 1521
TI: Nitrogen isotope fractionation by oceanic zooplankton.
AU: Checkley,-D.M.,Jr.; Miller,-C.A.
AF: Dep. Mar., Earth, and Atmos. Sci., Box 8208, North Carolina State Univ., Raleigh, NC 27695-8208, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1989. vol. 36, no. 10, pp. 1449-1456
LA: English
ER: M (Marine)
AB: The ratio of super(15)N: super(14)N for particulate matter suspended in oceanic, surface waters is high after recent nitrate depletion and low in the stable, oligotrophic ocean. We hypothesize that zooplankters and other pelagic heterotrophs produce super(15)N-depleted ammonium and super(15)N-enriched particulate matter that are, respectively, recycled in and exported from the euphotic zone and thus cause the low values of super(15)N: super(14)N in oligotrophic seas. Heretofore, this pattern was attributed to nitrogen-fixation by the phytoplankton. We measured the ratio of super(15)N: super(14)N in the bodies and excreted ammonium of zooplankters from the northwest Pacific Ocean and compared these values to the ratio of super(15)N: super(14)N for subeuphotic, dissolved nitrate.
AN: 2190147
1357 of 1521
TI: Phytoplankton, nutrients, and turbidity in the Chesapeake, Delaware, and Hudson estuaries.
AU: Fisher,-T.R.; Harding,-L.W.,Jr.; Stanley,-D.W.; Ward,-L.G.
AF: Univ. Maryland-CEES, Horn Point Environ. Lab., Cambridge, MD 21613, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1988. vol. 27, no. 1, pp. 61-93
LA: English
ER: M (Marine)
AB: Estuaries receive continuous inputs of nutrients from their freshwater sources; but the fate of the inputs is poorly known. Chesapeake and Delaware Bays frequently show a turbidity maximum in the oligohaline region, a chlorophyll maximum in clearer waters seaward of the turbidity maximum, and a nutrient-depleted zone at the highest salinities. In the Hudson River estuary, mixing diagrams were dominated by lateral waste inputs from New York City, and nutrient removal could not be estimated. In Chesapeake Bay, there was consistent removal of total N, nitrate, phosphate, and silicate from the water column, whereas in Delaware Bay, total N, ammonium, total P, and phosphate were removed. Phytoplankton accumulation was associated with inorganic nutrient removal, suggesting that phytoplankton uptake was a major process responsible for nutrient removal.
AN: 2190068
1358 of 1521
TI: Production of biologically refractory dissolved organic carbon by natural seawater microbial populations.
AU: Brophy,-J.E.; Carlson,-D.J.
AF: Coll. Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1989. vol. 36, no. 4A, pp. 497-507
LA: English
ER: M (Marine)
AB: Carbon from glucose and leucine added at natural concentrations to seawater was biologically transformed to higher molecular weight (mol. wt) dissolved materials that persisted through 6 months of incubation. At the end of incubation, the amount of carbon in high mol. wt dissolved fractions was approximately equal to the amount of carbon incorporated into particulate fractions. In tests of their resistance to biological utilization, only 1-17% of the high mol. wt materials were respirated when re-incubated with seawater microbial populations, whereas 40-75% of the monomers were respired over the same time span. In situ transformations of biologically available carbon may be an important source of refractory dissolved organic carbon in the oceans.
AN: 2189884
1359 of 1521
TI: Nutrient fluxes during extended blooms of Arctic ice algae.
AU: Cota,-G.F.; Prinsenberg,-S.J.; Bennett,-E.B.; Loder,-J.W.; Lewis,-M.R.; Anning,-J.L.; Watson,-N.H.F.; Harris,-L.R.
AF: Dep. Fish. and Oceans, Mar. Ecol. Lab., Bedford Inst. Oceanogr., Dartmouth, N.S., Canada
SO: J.-GEOPHYS.-RES.-C-OCEANS. 1987. vol. 92, no. C2, pp. 1951-1962
LA: English
ER: M (Marine)
AB: Estimates of nutrient demand by dense mats of ice algae in the high Arctic indicate that substantial nutrient fluxes are necessary to satisfy the observed growth over the 2-month bloom. In our study area, Barrow Strait, the quantity of nutrients in the surface-mixed layer is about 3-10 times greater than estimates of total demand during the bloom, and nutrient fluxes in the water column are estimated to be of the same order of magnitude as algal demand. In the latter half of the bloom, when biomass levels are high, it appears that established populations of ice algae may experience cyclic conditions of nutrient limitation during neap tides when nutrient fluxes are minimal.
AN: 2187122
1360 of 1521
TI: Biological nitrogen fixation (acetylene reduction) associated with green algal (cyanobacterial) communities in the Beachwood Mangrove Nature Reserve. 1. The effect of environmental factors on acetylene reduction activity.
AU: Mann,-F.D.; Steinke,-T.D.
AF: Dep. Bot., Univ. Durban-Westville, Priv. Bag X54001, Durban 400, South Africa
SO: S.-AFR.-J.-BOT.-S.-AFR.-TYDSKR.-PLANTKD. 1989. vol. 55, no. 4, pp. 438-446
LA: English
AB: Nitrogen fixation of blue-green algae (cyanobacteria) associated with Avicennia marina (Forssk.) Vierh. pneumatophores and wet and dry surface sediments was investigated in the Beachwood Mangrove Nature Reserve by means of the acetylene reduction technique. Studies revealed percentage moisture and temperature to be the prime factors influencing ARA (acetylene reduction activity) in these habitats and rates were highest under submerged conditions and at 22 degree C. High concentrations of inorganic nitrogen (between 1 and 5 mg/l) significantly depressed ARA in all habitats. Increases in ARA occurred with increase in light intensity up to 40 mu E m super(-2)/s, with negligible dark rates being recorded in association with the wet and dry surface sediments. Significant dark rates of ARA and stimulation of ARA by sucrose in association with the pneumatophores indicated that bacteria may also be contributing to ARA in this habitat. No organic carbon stimulation was noted in the other sites. Salinity had little effect on ARA over the range generally experienced in each habitat.
AN: 2183566
1361 of 1521
TI: Preliminary studies of fungi communities on Rhizophora mangle .
AU: Barreto,-M.B.; Bastardo,-H.; Bonilla,-A.
AF: Inst. Zool. Trop., Univ. Cent. Venezuela, PBO 47058 Caracas 1041-A, Venezuela
CA: Japanese Soc. for Marine Biotechnology, Tokyo (Japan)
Foundation for Advancement of International Science
ICSU Int. Scientific Comm. for Biotechnology
CO: 1. Int. Marine Biotechnology Conf. (IMBC '89), Tokyo (Japan), 4-6 Sep 1989
SO: PROGRAM-OF-THE-FIRST-INTERNATIONAL-MARINE-BIOTECHNOLOGY-CONFERENCE-IMBC-'-89. 1989. p. 79
NT: Summary only.
LA: English
ER: M (Marine)
AB: An important coastal zone in tropical and sub-tropical zones is dominated by mangrove forest. Its plays an important role in the productivity of detritus biomass of estuarine ecosystems. Recently there has been a great interest for the activity of fungi in the decomposition processes of mangrove roots from the point of view of the importance of these functional groups during the dynamics of mineralization of plant material from mangrove forest. Rhizophora mangle and water samples were taken from Tacarigua Lagoon and cultivated in Petri dishes by spread method. Among the most abundant were Aspergillus sp. and Penicillum which represent 44% of the total population. The biochemical tests performed on the fungal community showed that the major percentage of fungi are able to degrade lignocellulose compounds and mineralize organic phosphorous and nitrogen.
AN: 2183477
1362 of 1521
TI: Cadmium movement and accumulation in a sediment-water-plant system.
AU: Peverly,-J.H.
AF: Dep. Agron., Cornell Univ., Ithaca, NY 14853, USA
CO: University of Missouri's 22. Annu. Conf. on Trace Substances in Environmental Health, St. Louis, MO (USA), 23-26 May 1988
SO: TRACE-SUBSTANCES-IN-ENVIRONMENTAL-HEALTH-22. Hemphill,-D.D.-ed. 1988. pp. 399-409
LA: English
ER: F (Freshwater)
AB: Studies in 1986 of cadmium (Cd) mobilization from dosed pond sediments after inputs stopped in 1983 indicated that Cd may be absorbed by rooted aquatic plants and thus returned to the aquatic food chain. The limits of this process were studied in 1987. Cd in plants, water, and sediments was determined and characterized in replicated, outdoor aquaria after single acute dosages. The aquaria were representative of the hardwater, non-flowing impoundments 1.1m deep used in 1986. Over 60 mgCd m super(-2) was absorbed from sediments by plants in the higher Cd treatments and accumulated in root and leaf tissues. Electron microscopy and x-ray analysis confirmed its presence in cell walls. This represented a considerable return of sediment Cd to the aquatic food chain.
AN: 2179692
1363 of 1521
TI: Cycling of methane, carbon monoxide, nitrous oxide, and hydroxylamine in a meromictic, coastal lagoon.
AU: Butler,-J.H.; Pequegnat,-J.E.; Gordon,-L.I.; Jones,-R.D.
AF: Coop. Inst. Res. Environ. Sci., Univ. Colorado/NOAA, Boulder, CO 80309, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1988. vol. 27, no. 2, pp. 181-203
LA: English
ER: B (Brackish)
AB: The vertical distributions of methane, carbon monoxide, nitrous oxide, and hydroxylamine were measured in a seasonally stratified, coastal lagoon in northern California. The production of gases was estimated from mass-balance calculations where possible, including considerations of diffusion and microbial oxidation. From late spring through most of the summer the lagoon remained oligotrophic, with biological activity concentrated near the pycnocline and the sediments.
AN: 2179189
1364 of 1521
TI: Spatial and temporal variability in south San Francisco Bay (USA). 2. Temporal changes in salinity, suspended sediments, and phytoplankton biomass and productivity over tidal time scales.
AU: Cloern,-J.E.; Powell,-T.M.; Huzzey,-L.M.
AF: U.S. Geol. Surv., MS 496, 345 Middlefield Rd., Menlo Park, CA 94025, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1989. vol. 28, no. 6, pp. 599-613
LA: English
ER: M (Marine); B (Brackish)
AB: Short-term variability of a conservative quantity (salinity) and two nonconservative quantities (chlorophyll a, suspended particulate matter) was measured across a sampling grid in the South San Francisco Bay estuary. Both chlorophyll a and SPM varied periodically with tidal stage (increasing on ebbing currents). For surface salinity, most (70-80%) of the observed intratidal variability was correlated with the tidal flux, both in the deep channel and over the lateral shoals. The short-term variability of SPM concentration was only weakly correlated with the advective flux, indicating that local sources of SPM (resuspension) are important. Hence, the magnitude and mechanisms of intratidal variability differ among constituents and among bathymetric regimes in this estuary.
AN: 2175002
1365 of 1521
TI: Periplatform carbonate flux in the northern Bahamas.
AU: Pilskaln,-C.H.; Neumann,-A.C.; Bane,-J.M.
AF: Monterey Bay Aquarium Res. Inst., Pacific Grove, CA 93950, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1989. vol. 36, no. 9A, pp. 1391-1406
LA: English
ER: M (Marine)
AB: In a preliminary effort to quantify the off-bank transport and vertical flux of shallow-water carbonates, a sediment trap was moored at 500 m in Northwest Providence Channel, northern Bahamas. Two months of particulate flux data collected during a fair-weather, storm-free period revealed that the flux components differed significantly from that of the underlying sediments. The results suggest that the flux and deposition of bank-derived carbonates in the periplatform environment are variable on a temporal scale, where a relatively minor proportion of bank-derived components is deposited during calm, storm-free periods, with the balance delivered during the passage of frequent, low-amplitude seasonal storms and occasional hurricanes.
AN: 2174291
1366 of 1521
TI: Amelioration of storm-water quality by a freshwater estuary.
AU: Klarer,-D.M.; Millie,-D.F.
AF: Ohio Dep. Nat. Resour., Old Woman Creek State Nat. Preserve and Natl. Estuar. Res. Reserve, 2514 Cleveland Rd., East, Huron, OH 44839, USA
SO: ARCH.-HYDROBIOL. 1989. vol. 116, no. 3, pp. 375-389
NT: Incl. 38 ref.
LA: English
ER: F (Freshwater)
AB: The role of Old Woman Creek estuary, Lake Erie (U.S.A.) in ameliorating the quality of storm-water flow was investigated. Chemical parameters in water samples collected immediately following three distinct storm events displayed one of three patterns: 1) decreasing concentrations due to dilution by storm-water runoff, 2) increasing concentrations due to sediment input and/or surface runoff, and 3) increasing concentrations attributed to storm interflow. Outflow/inflow ratios of chemical concentrations indicated that up to 60% of the metals and up to 80% of the biologically-important nutrients were retained within the estuary. Amelioration of storm-water quality was attributed to sedimentation, biological uptake, and geochemical processes.
AN: 2169204
1367 of 1521
TI: In situ holographic imaging of settling particles: Applications for individual particle dynamics and oceanic flux measurements.
AU: Costello,-D.K.; Carder,-K.L.; Betzer,-P.R.; Young,-R.W.
AF: Dep. Mar. Sci., Univ. South Florida, 140 Seventh Ave. South, St. Petersburg, FL 33701, USA
SO: DEEP-SEA-RES.-A-OCEANOGR.-RES.-PAP.. 1989. vol. 36, no. 10, pp. 1595-1605
LA: English
ER: M (Marine)
AB: A new dual-axis holographic imaging system provides a means for estimating in situ the sizes, shapes, settling rates and densities of both individual particles and aggregates. The optical system utilizes two independent imaging systems with HeNe laser illumination to record holographically the particles moving through the collection cup from two orthogonal perspectives. Four free-drifting, holographically equipped sediment traps have been utilized on three cruises to the North Pacific Ocean. The holographically determined dynamic densities for individual particles include high-density material of eolian origin and also lower density organic material. Such optically enhanced sediment traps provide a means of directly recording particle settling dynamics and may also provide insight into biological activity within sediment traps.
AN: 2164315
1368 of 1521
TI: Geochemical characteristics of transformation of inorganic sulfur in the Black Sea water column.
OT: Geokhimicheskie osobennosti transformatsii neorganicheskikh form sery v tolshche vod Chernogo morya
AU: Sovga,-E.E.; Eremeev,-L.V.; Solov'-eva,-L.V.
AF: Mor. Gidrofiz. Inst. AN Ukrainian SSR, Sevastopol', Ukrainian SSR, USSR
SO: GEOKHIMIYA. 1989. no. 11, pp. 1648-1655
LA: Russian
ER: M (Marine)
AB: Based on the results of surveys made during the 44th cruise of the R/V Mikhail Lomonosov a scheme was constructed showing S transformations as a result of chemical and microbiological processes. Areas are revealed of active S reduction and intense oxidation of H sub(2)S in the zone of coexistence of O sub(2) and H sub(2)S and in the off-bottom layer. Microbiological mechanism of molecular S occurrence in the water column in considered in detail.
AN: 2163720
1369 of 1521
TI: Microbiological and biogeochemical processes in the oceanic water column as indicators of hydrothermal activity.
OT: Mikrobiologicheskie i biogeokhimicheskie protsessy v vodnoj tolshche okeana kak pokazateli aktivnosti podvodnykh gidroterm
AU: Gal'-chenko,-V.F.; Ivanov,-M.V.; Lein,-A.Yu.
AF: Inst. Mikrobiol. AN SSSR, Moscow, USSR
SO: GEOKHIMIYA. 1989. no. 8, pp. 1075-1088
LA: Russian
ER: M (Marine)
AB: An approximate method is described aimed at detecting hydrothermal spring from board the vessel based on dark fixation of 14CO sub(2) and CH sub(4) oxidation using 14C isotope and bacterial counts. The abundance of bacteria was by 1-2 orders higher in near-bottom waters above hydrothermal fields and the microbial activity was by 2-4 orders higher than in the rest of the water column. Anomalous abundance of specific groups of bacteria was in good agreement with anomalous physicochemical parameters (Eh, optical density) and anomalously high content of dissolved Mn. An operating model is considered of a hydrothermal plume which is differentiated by CH sub(4) oxidation and CO sub(2) fixation.
AN: 2163697
1370 of 1521
TI: Strategic marine research -- new Sea Grant initiative.
AU: Attaway,-D.H.
AF: Natl. Sea Grant Coll. Program, NOAA, Rockville, MD 20852, USA
SO: SEA-TECHNOL. 1989. vol. 30, no. 7, pp. 33-34
LA: English
ER: M (Marine)
AB: The term "global change" is used increasingly to describe the basis of a unified scientific effort. Cooperative efforts among several agencies led to two interagency reports, the U.S. Global Ocean Science Program (USGOSP) and Our Changing Planet: A U.S. Strategy for Global Change Research. These reports represent the first stage of coordinated efforts in strategic planning by federal agencies. The National Sea Grant College Program has an essential role to play in these programs. This role corresponds with its meeting needs in strategic research called for recently in Public Law 100-220, particularly in three major areas identified. These are: 1) Biogeochemical dynamics; 2) Global ecosystems and productivity processes; and 3) Coastal margins and polar ocean processes.
AN: 2158432
1371 of 1521
TI: Temporal changes in interstitial water chemistry and calcite recrystallization in marine sediments.
AU: Delaney,-M.L.
AF: Inst. Mar. Sci., Univ. California, Santa Cruz, CA 95064, USA
SO: EARTH-PLANET.-SCI.-LETT. 1989. vol. 95, no. 1-2, pp. 23-37
LA: English
ER: M (Marine)
AB: Recrystallization processes in marine sediments can alter the extent to which biogenic calcite composition serves as a proxy of oceanic chemical and isotopic history. Realistic, albeit simplified, models of the temporal evolution of interstitial water profiles of Ca, Mg, and Sr were used with several patterns of recrystallization rate variation to predict the composition of recrystallized inorganic calcite. Comparison of predictions with measured Mg/Ca and Sr/Ca ratios in severely altered calcite samples from several Deep Sea Drilling Project sites demonstrates that models incorporating temporal variation in interstitial water composition more successfully predict observed calcite compositions than do models which rely solely on present-day interstitial water chemistry.
AN: 2154287
1372 of 1521
TI: The dynamic greenhouse: Feedback processes that may influence future concentrations of atmospheric trace gases and climatic change.
AU: Lashof,-D.A.
AF: U.S. Environ. Prot. Agency, Washington, DC 20460, USA
SO: CLIM.-CHANGE. 1989. vol. 14, no. 3, pp. 213-242
LA: English
ER: M (Marine)
AB: The sensitivity of the climate system to anthropogenic perturbations over the next century will be determined by a combination of feedbacks that amplify or damp the direct radiative effects of increasing concentrations of greenhouse gases. A number of important geophysical climate feedbacks, such as changes in water vapor, clouds, and sea ice albedo, are included in current climate models, but biogeochemical feedbacks such as changes in methane emissions, ocean CO sub(2) uptake, and vegetation albedo are generally neglected. The relative importance of a wide range of feedbacks is assessed here by estimating the gain associated with each individual process. While each of these feedbacks is modest compared to the water vapor feedback, the biogeochemical feedbacks in combination have the potential to substantially increase the climate change associated with any given initial forcing.
AN: 2143944
1373 of 1521
TI: Anaerobic degradation of betaine by marine Desulfobacterium strains.
AU: Heijthuijsen,-J.H.F.G.; Hansen,-T.A.
AF: Dep. Microbiol., Univ. Groningen, Kerklaan 30, NL-9751 NN Haren, Netherlands
SO: ARCH.-MICROBIOL. 1989. vol. 152, no. 4, pp. 393-396
LA: English
ER: M (Marine)
AB: From enrichment cultures with betaine (20 mM) and sulfate (20 mM) as the substrates and intertidal mud as an inoculum, a betaine-oxidizing, sulfate-reducing bacterium (strain PM4) was isolated. Strain PM4 was an oval to rod-shaped, Gram-negative, motile bacterium, which was able to oxidize lactate completely to CO sub(2) and contained, during growth on betaine and sulfate, high activities of key enzymes of the acetyl CoA/CO dehydrogenase pathway (carbon monoxide dehydrogenase and formate dehydrogenase), but not of 2-oxo-glutarate dehydrogenase, a key enzyme of the citric acid cycle. On the basis of its morphological and physiological characteristics, strain PM4 was identified as a Desulfobacterium) strain. Desulfobacterium PM4 grew on betaine with a doubling time of approximately 20 h at 30 degree C and produced N, N-dimethylglycine (in a 1:1 ratio) and sulfide as products. In this type of betaine metabolism one of the methyl groups of betaine is oxidized to CO sub(2) and the reducing equivalents general are used for the reduction of sulfate.
AN: 2143299
1374 of 1521
TI: Sterols in ocean sediments: Novel tracers to examine habitats of cetaceans, pinnipeds, penguins and humans.
AU: Venkatesan,-M.I.; Santiago,-C.A.
AF: Inst. Geophys. and Planet. Phys., Univ. California, Los Angeles, CA 90024, USA
SO: MAR.-BIOL. 1989. vol. 102, no. 4, pp. 431-437
NT: 34 ref.
LA: English
ER: M (Marine)
AB: The role of marine mammals in the biogeochemical flux of oceanic carbon is largely unknown. Capillary gas chromatography and gas chromatography/mass spectrometry after organic solvent extraction and compound class separation of feces from cetaceans (toothed and baleen whales), pinnipeds and penguins (collected in 1987 from Monterey Bay, off the coast of California or from Sea World, San Diego, California, USA) indicate that the unusual sterol profile in the Antarctic sediments, with epicoprostanol predominating over its isomer, coprostanol, originates from baleen whales (blue and fin whales). The sterol distribution in feces from baleen whales is different from that of other animals studied here and also from anthropogenic sewage (collected in 1987 from wastewater outfalls off the coast of southern California, USA).
AN: 2141232
1375 of 1521
TI: Seasonal changes in the silicon cycle within a Gulf Stream warm-core ring.
AU: Brzezinski,-M.A.; Nelson,-D.M.
AF: Dep. Biol. Sci., Univ. California, Santa Barbara, CA 93106, USA
SO: DEEP-SEA-RES. 1989. vol. 36, no. 7A, pp. 1009-1030
LA: English
ER: M (Marine)
AB: The silicon cycle within Gulf Stream warm-core ring 82-B was examined before and after spring stratification using silicon isotope tracers. In April, prior to stratification, the ring was isothermal and isohaline to 400 m. Ambient silici acid concentrations were ca 3 mu mol/l and biogenic silica concentrations ranged from 80 to 100 nmol/l throughout this depth range. By June, a seasonal pycnocline had developed and silicic acid concentrations were depleted to less than or equal to 0.2 mu mol/l in the upper 20-30 m. Vertically integrated particulate silica concentrations in the upper 80 m had increased four-fold compared to those for the upper 110 m in April/May. Siliceous biomass was concentrated in the upper 40 m, with a subsurface maximum of ca 1000 nmol Si/l within the seasonal pycnocline. The upper 80 m remained a zone of net silica production, but net dissolution was occurring at all depths > 100 m.
AN: 2139364
1376 of 1521
TI: A peat fire in the Okavango Delta, Botswana, and its importance as an ecosystem process.
AU: Ellery,-W.N.; Ellery,-K.; McCarthy,-T.S.; Cairncross,-B.; Oelofse,-R.
AF: Dep. Bot., Univ. Witwatersrand, PO Wits, Johannesburg 2050, South Africa
SO: AFR.-J.-ECOL. 1989. vol. 27, no. 1, pp. 7-21
LA: English
ER: F (Freshwater)
AB: The progressive abandonment and desiccation of the lower Nqoga River system and its associated vegetation-covered peat deposits, has resulted in the development of subsurface peat fires. These appear to have been burning within the study area for decades and consist of a mosaic of burning fronts, the first of which burns to a depth of up to 15 cm. This relatively shallow fire destroys the bases of stems and plant rhizomes, thereby preventing re-establishment of the former plant community by vegetative growth. The depths to which these burn are limited by peat moisture content or by the presence of an incombustible inorganic substrate. The initial collapse is some 30-40 vol.%. Further compaction is brought about by rainfall and animal trampling which may cause volume reductions of as much as 98%.
AN: 2139353
1377 of 1521
TI: Litter production and turnover of the mangrove Kandelia candel (L.) Druce in a Hong Kong tidal shrimp pond.
AU: Lee,-S.Y.
AF: Dep. Zool., Univ. Hong Kong, Pokfulam Rd., Hong Kong
SO: ESTUAR.-COAST.-SHELF-SCI. 1989. vol. 29, no. 1, pp. 75-87
LA: English
ER: M (Marine)
AB: Production and turnover of Kandelia candel litter were studied for 2 years in a tidal shrimp pond (10 ha) at the Mai Po Marshes, northwest Hong Kong. Stand characteristics of average tree height and dbh were good predictors of litter production while climatic variables, especially rainfall, could be used to predict the production of various litter components. Residence times were related to both inundation frequency and crab (Chiromanthes spp.) consumption. As the Kandelia candel stands were located largely above mean water level, there was little export of litter. The litter produced was predominantly decomposed or consumed by macrofauna in situ, creating a large energy sink which was not coupled to pelagic secondary production. The significance of these findings are discussed in relation to the fishery production and wildlife conservation value of the marshes.
AN: 2139313
1378 of 1521
TI: Palaeoclimate analysis of super(2)H/ super(1)H ratios in peat sequences with variable plant composition.
AU: Dupont,-L.M.; Mook,-W.G.
AF: Inst. Palynol. und Quartaerwiss., Univ. Goettingen, Wilhelm-Weber-Str. 2, D-3400 Goettingen, FRG
SO: CHEM.-GEOL.-ISOT.-GEOSCI.-SECT. 1987. vol. 7, no. 3-4, pp. 323-333
LA: English
ER: F (Freshwater)
AB: Under equal climatic conditions the deuterium content of plants varies with species. The deuterium content of peat cellulose, therefore, is related to the plant composition. This dependence is calculated for each taxon in specific peat sequences by means of multiple linear regression, and subtracted from the deuterium content of the cellulose fraction of each sample. The residual variation should contain a climatic effect such as the climatic temperature dependence of super(2)H/ super(1)H in precipitation, which is to be correlated with other palaeotemperature records.
AN: 2138763
1379 of 1521
TI: Early incorporation of polysulphides in sedimentary organic matter.
AU: Kohnen,-M.E.L.; Sinninghe-Damste,-J.S.; ten-Haven,-H.L.; de-Leeuw,-J.W.
AF: Org. Geochem. Unit, Fac. Chem. Technol. and Mater. Sci., Delft Univ. Technol., de Vries van Heystplantsoen 2, NL-2628 RZ Delft, Netherlands
SO: NATURE. 1989. vol. 341, no. 6243, pp. 640-641
LA: English
ER: M (Marine)
AB: The increase in sulphur content of organic matter with depth in Recent sediments has been attributed to incorporation of either H sub(2)S or polysulphides or to a combination of both. Here the authors report the identification of homologous series of cyclic disulphides with a linear carbon skeleton and of a cyclic di- and trisulphide with a C sub(20) isoprenoid carbon skeleton in sediments of Quaternary to Pliocene age. Although incorporation of H sub(2)S can still explain the presence of cyclic disulphides, the cyclic trisulphide implies incorporation of inorganic polysulphides in sedimentary organic matter at the earliest stages of diagenesis.
AN: 2138325
1380 of 1521
TI: Sedimentary sulfides in the nearshore Georgia Bight.
AU: Fallon,-R.D.
AF: E.I. Du Pont Co., Haskell Lab. Toxicol. and Ind. Med., Elkton Rd., Newark, DE 19711, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1987. vol. 25, no. 6, pp. 607-619
LA: English
ER: M (Marine)
AB: Sedimentary sulfide, iron, and organic matter were measured in neritic sediments from the Georgia Bight. The two measured depth integrated sulfur pools, FeS + HS super(-) and FeS sub(2), tended to decrease with increasing distance from shore out to 33 km. Total iron and organic matter were strongly correlated and both tended to decrease with increasing distance from shore. Sediment depth profiles of organic matter/reduced sulfur suggest relatively constant rates of sulfate reduction over the top 40 cm of sediment. Differences in within-station variance indicated regions of lower and higher spatial/temporal heterogeneity, that may be related to tidally driven circulation patterns. No seasonal cycles were evident in sedimentary sulfides.
AN: 2135623
1381 of 1521
TI: Decomposition and the annual flux of detritus from fallen timber in tropical mangrove forests.
AU: Robertson,-A.I.; Daniel,-P.A.
AF: Australian Inst. Mar. Sci., PMB No. 3, Townsville MC, Qld. 4810, Australia
SO: LIMNOL.-OCEANOGR. 1989. vol. 34, no. 3, pp. 640-646
LA: English
ER: M (Marine)
AB: Single exponential decay models fitted to dry mass and carbon decomposition data for tree trunks in mixed Rhizophora mangrove forests in tropical Australia had decay constants of 0.083 and 0.108/yr respectively. Decay of twigs and small branches was more rapid with decay constants of 0.276 (dry mass) and 0.310/yr (carbon). Aboveground standing stocks of dead wood components in young and mature forests were (g C m super(-2)): trunks, 15.3 and 221.9; prop roots, 5.7 and 86.8; branches, 3.5 and 32.2; twigs, 3.2 and 3.1.
AN: 2134628
1382 of 1521
TI: Microbiological processes in bottom sediments of the Kraternaya Bay.
OT: Mikrobiologicheskie protsessy v donnykh osadkakh bukhty Kraternoj
AU: Namsaraev,-B.B.; Karnachuk,-O.V.; Borzenkov,-I.A.; Starynin,-D.A.
AF: Inst. Mikrobiol. AN SSSR, Moscow, USSR
SO: BIOL.-MORYA-MAR.-BIOL.,-VLADIVOST. 1989. no. 3, pp. 52-58
LA: Russian
ER: M (Marine)
AB: A study was made of microbiological processes of synthesis and destruction of the organic matter in bottom sediments of the Kraternaya Bay (the Kuril Islands). High concentrations of bacteria and algae (algobacterial mats) were observed in the areas of gas and hydrothermal vents. The rate of organic matter synthesis in algobacterial mats varied from 2,343 to 5,940 mgC/l of wet sediment per day. Photosynthesis yielded only 112-740 mgC/l/day. In silt sediments of the Bay the rate of organic matter synthesis was by 2-3 orders of magnitude lower. High rates of microbic destruction of albumen and cellulose especially in algobacterial mats were recorded. Estimation of rates of organic matter destruction at terminal stages revealed that the bulk of organic matter is expended during sulphate reduction with the leading role of methanogenesis.
AN: 2132089
1383 of 1521
TI: Scientific research and management of coastal environments. The critical path approach to the notion of assimilation capacity.
OT: Recherche scientifique et gestion de l'environnement marin. Critique de la notion de capacite d'assimilation
AU: Marin,-J.-M.
AF: Inst. Biogeochim. Mar., Ec. Norm. Super., 1 Rue Maurice-Arnoux, 92120 Montrouge, France
CA: Ministere de l'Environnement, Paris (France). Com. Scientifique Milieu Marin
CO: Devenir des Polluants Chimiques en Milieu Marin, Brest (France), 26-27 Jan 1988
SO: FATE-OF-CHEMICAL-POLLUTANTS-IN-THE-MARINE-ENVIRONMENT:-SEMINAR-OF-THE-SCIENTIFIC-COMMITTEE-"MARINE-ENVIRONMENT"-OF-THE-ENVIRONMENT-MINISTRY,-BREST,-26-27-JAN-1988. DEVENIR-DES-POLLUANTS-CHIMIQUES-EN-MILIEU-MARIN:-SEMINAIRE-DU-COMITE-SCIENTIFIQUE-"MILIEU-MARIN",-MINISTERE-L'-ENVIRONNEMENT,-BREST,-26-27-JAN-1988. 1988. vol. 14, no. 6 pp. 751-762
ST: OCEANIS-DOC.-OCEANOGR.. vol. 14, no. 6
LA: French
ER: M (Marine)
AB: A "Critical Path Approach" (C.P.A.) to the notion of "Assimilation Capacity" (A.C.) is presented. Apart from the terminological problems involved and the political and socio-economic difficulties encountered when defining the assimilation capacity, other practical problems are discussed. This is an interesting procedure from the scientific point of view, although difficult to apply to a coastal environment, for the biogeochemical cycle and the long-term fate of numerous pollutants are still insufficiently known.
AN: 2126672
1384 of 1521
TI: Chemical cycling in Washington's coastal zone.
AU: Carpenter,-R.; Peterson,-M.L.
AF: Sch. Oceanogr., Univ. Washington, Seattle, WA 98195, USA
SO: COASTAL-OCEANOGRAPHY-OF-WASHINGTON-AND-OREGON. Landry,-M.R.;Hickey,-B.M.-eds. 1989. vol. 47 pp. 367-510
ST: ELSEVIER-OCEANOGR.-SER. vol. 47
LA: English
ER: M (Marine)
AB: Studies since the early 1970s have focused on chemicals which are of concern due to their persistence and relatively toxic natures, such as the Pu isotopes, super(210)Po, super(210)Pb, As, Hg and polynuclear aromatic hydrocarbons. Major improvements in sample collection, preparation and analytical chemistry capabilities have been made for determinations of trace organic compounds, stable metals and their speciation and radionuclides in environmental samples. Most of these improvements have been exploited in studies of chemical cycling off the Washington coast and are described in greater detail throughout this chapter. This chapter will review developments in our understanding of the biogeochemical cycling of primarily these toxic and persistent compounds.
AN: 2119135
1385 of 1521
TI: Flux and recycling of bioactive substances in the surface sediments of the deep basins off southern California: Progress report, November 1987-July 1988.
AU: Jahnke,-R.A.
CA: Skidaway Inst. of Oceanography, Savannah, GA (USA)
SO: REP.-U.S.-DEP.-ENERGY. 1989. 4 pp
NT: NTIS Order No.: DE88014251/GAR.
RN: DOE/ER/60627-1 (DOEER606271)
LA: English
ER: M (Marine)
AB: Goals of this project are to develop an understanding of the processes responsible for the recycling of biogenic debris in the surface sediments of Santa Monica Basin and to quantitatively determine the rate at which dissolved chemicals exchange across the sediment-bottom water boundary. This information will provide fundamental information about organic matter decomposition and oxidation at the seafloor as well as provide a quantitative minimum estimate of the lateral input of organic matter to the deep basin from the adjacent continental shelf. We developed a preliminary organic carbon budget for the seafloor based on pore water and in situ benthic chamber flux measurements. The latter were performed with the MANOP Bottom Lander free-vehicle which was developed during the NSF sponsored Manganese Nodule Program. (Contract FG09-88ER60627. Portions of this document are illegible in microfiche products.)
AN: 2117664
1386 of 1521
TI: A geochemical perspective on the causes and periodicity of mass extinctions.
AU: Moses,-C.O.
AF: Dep. Geol. Sci., Lehigh Univ., Bethlehem, PA 18015, USA
SO: ECOLOGY. 1989. vol. 70, no. 4, pp. 812-823
LA: English
ER: M (Marine)
AB: Environmental change, including changes in biogeochemical cycles, climate, and sea level, is the primary cause of extinctions that result from mechanisms external to evolutionary dynamics. Evidence that extraordinary tectonism, including volcanism, seafloor spreading, and eustatic sea level changes, took place prior to and at the Cretaceous-Tertiary boundary (K-TB) is sufficient to account for the environmental changes that led to mass extinctions. A coincident impact of an extraterrestrial object cannot be conclusively ruled out. Some mineralogic evidence suggests a scenario that includes impacts, but this does not rule out tectonism. The K-TB is certainly the best studied and most often discussed extinction boundary, but study of other extinction episodes and other potential extinction causes will now shed more light on mechanisms than continued study of the K-TB.
AN: 2106433
1387 of 1521
TI: (Radioecology of freshwater biosystems.).
OT: Radioehkologiya presnovodnykh biosystem
AU: Kulikov,-N.V.; Chebotina,-M.Ya.
SO: SVERDLOVSK-USSR-URO-AN-S.S.S.R. 1988. 129 pp
NT: Incl. bibliogr.: 194 ref.
LA: Russian
ER: F (Freshwater)
AB: The monograph summarizes the results of long-term studies on behaviour of various radionuclides in water-hydrobionts and water-ground model systems as dependent on concentration of isotopic and non-isotopic carriers, pH, light, temperature and season of the year. Effect of ionizing radiation on freshwater organisms and communities is discussed with reference to external sources and ambient radioactive contamination.
AN: 2098760
1388 of 1521
TI: Non-steady-state biological removal of atmospheric particles from Mediterranean surface waters.
AU: Buat-Menard,-P.; Davies,-J.; Remoudaki,-E.; Miquel,-J.C.; Bergametti,-G.; Lambert,-C.E.; Ezat,-U.; Quetel,-C.; La-Rosa,-J.; Fowler,-S.W.
AF: Cent. Faibles Radioact., Lab. Mixte CNRS-CEA, Domaine CNRS, F-91198 Gif sur Yvette Cedex, France
SO: NATURE. 1989. vol. 340, no. 6229, pp. 131-134
LA: English
ER: M (Marine)
AB: Here the authors report data from time-series measurements of both atmospheric inputs and water-column particulate fluxes at 200 m depth obtained from sediment traps, which show that such a biological control also prevails in northwestern Mediterranean waters. On short time-scales, concentrations and fluxes in the upper water column can increase significantly following dust transport and deposition events, with a response time of the order of one week. Such non-steady-state behaviour must be taken into account when assessing the impact of pulsed atmospheric inputs on particulate trace element concentrations and fluxes in the water column.
AN: 2089209
1389 of 1521
TI: Numerical models for predicting watershed acidification.
AU: Eary,-L.E.; Jenne,-E.A.; Vail,-L.W.; Girvin,-D.C.
AF: Battelle, Pac. Northwest Lab., Environ. Sci. Dep., P.O. Box 999, Richland, WA 99352, USA
SO: ARCH.-ENVIRON.-CONTAM.-TOXICOL. 1989. vol. 18, no. 1-2, pp. 29-53
NT: Special issue: Acid rain.
LA: English
ER: F (Freshwater)
AB: Three numerical models of watershed acidification, including the MAGIC II, ETD, and ILWAS models, are reviewed, and a comparative study is made of the specific process formulations that are incorporated in the models to represent hydrological, geochemical, and biogeochemical processes which affect the responses of watersheds to acidic deposition. The models have been used to simulate the short-term dynamics of water quality at a number of different watersheds currently receiving acidic deposition.
AN: 2081027
1390 of 1521
TI: Oxygen consumption and nutrient regeneration ratios along isopycnal horizons in the Pacific Ocean.
AU: Boulahdid,-M.; Minster,-J.F.
AF: GRGS/UM 39, 18 Ave. Edouard Belin, 31055 Toulouse Cedex, France
SO: MAR.-CHEM. 1989. vol. 26, no. 2, pp. 133-153
LA: English
ER: M (Marine)
AB: The P/N/-O sub(2) Redfield ratios were re-estimated from variations of the dissolved concentrations along five isopycnal surfaces of the Pacific Ocean, using the Geosecs data. Nutrients in the South Pacific shallow waters can be explained by mixing of two end-members and regeneration. Very high Redfield ratios are found (P/N/-O sub(2) = 1/20.1/195). In the tropical areas, a similar model would give more classical values of P/N/-O sub(2) = 1/15.4/165. This difference can either be owing to diapycnal mixing or to the fact that phosphates are not limiting production in this area.
AN: 2078096
1391 of 1521
TI: Some organic components in the sediments of Hooghly Estuary.
AU: Ghosh,-P.B.; Choudhury,-A.
AF: Dep. Mar. Sci., Univ. Calcutta, Calcutta 700019, India
SO: ENVIRON.-ECOL. 1989. vol. 7, no. 2, pp. 395-397
LA: English
ER: M (Marine); B (Brackish)
AB: Organic carbon, hydrocarbon, fatty acid, sterol and terpene content in the sediments of Hooghly Estuary covering three stations were studied. All the components showed some seasonal variation in concentration. Organic carbon, fatty acid and hydrocarbon were high in monsoon season at station 2 whereas sterol and terpene were comparatively high in postmonsoon season at all stations. The variations of organic carbon and fatty acid were directly correlation with the texture of the sediments while hydrocarbon, sterol and terpene were not.
AN: 2076899
1392 of 1521
TI: Aerosol transport of polynuclear aromatic hydrocarbons over the Mediterranean Sea.
AU: Grimalt,-J.; Albaiges,-J.; Sicre,-M.A.; Marty,-J.C.; Saliot,-A.
AF: Dep. Environ. Chem., CID-CSIC, E-08034 Barcelona, Spain
SO: NATURWISSENSCHAFTEN. 1988. vol. 75, no. 1, pp. 39-42
LA: English
ER: M (Marine)
AB: The occurrence of polynuclear aromatic hydrocarbons (PAH) in open marine areas is usually attributed to atmospheric inputs. However, at present, almost no data exist on the PAH composition in marine aerosols, representing an important lack of knowledge for the understanding of the biogeochemical cycle of these hydrocarbons. The authors present a study on the composition of PAH in particle-size aerosols collected over the open sea (Western Mediterranean) showing for first time the importance of their atmospheric deposition fluxes. The results are also discussed in terms of air mass trajectories, organic sources, and particle size association.
AN: 2073689
1393 of 1521
TI: Investigating the fate of dyes in the environment.
AU: Baughman,-G.L.; Perenich,-T.A.
CA: Environmental Protection Agency, Athens, GA (USA). Environmental Research Lab.
SO: ECOL.-RES.-SER.-U.S.-ENVIRON.-PROT.-AGENCY. 1988. 11 pp
NT: NTIS Order No.: PB88-184619/GAR.
RN: EPA/600/D-88/050 (EPA600D88050)
LA: English
AB: The rationale and approach that underlie the use of mathematical models to forecast the environmental behavior of organic chemicals are examined. The general concepts are then used to show how knowledge of environmental and dye chemistry can be used to suggest pathways that are likely or unlikely to be determinants of dye fate in aquatic systems. The uncharged dyes are considered in regard to possible volatilization, sorption, and bioconcentration. Suitable kinetic and equilibrium constants are not currently available for quantitative prediction using mathematical models.
AN: 2064547
1394 of 1521
TI: Microbial and animal processing of detritus in a woodland stream.
AU: Petersen,-R.C.,Jr.; Cummins,-K.W.; Ward,-G.M.
AF: Stream and Benthic Ecol. Group, Dep. Ecol. and Limnol., Univ. Lund, Box 65, 22100 Lund, Sweden
SO: ECOL.-MONOGR. 1989. vol. 59, no. 1, pp. 21-39
LA: English
ER: F (Freshwater)
AB: The detritus standing crop, microbial respiration, and macroinvertebrate biomass were examined in monthly samples from the riffle sections of a first-order woodland stream. Total detritus was remarkably constant. Decreases in standing crop were attributable to microbial respiration, macroinvertebrate assimilation, and downstream export. Microbial respiration annually removed 150% of the average standing crop, with the major effect on the smallest particle size category. Macroinvertebrate assimilation, defined as the sum of respiration and growth, removed 11.6% of the detritus standing crop annually. Shredders accounted for 20% of total animal assimilation, with the remaining 80% attributable to collectors and grazers.
AN: 2062009
1395 of 1521
TI: Indicative parameters of denitrification in river sediments.
AU: Muela,-A.; Gorostiza,-I.; Iriberri,-J.; Egea,-L.
AF: Dep. Microbiol., Fac. Cienc., Univ. Pais Vasco, Apdo. 644, E-48080 Bilbao, Spain
SO: ACTA-HYDROCHIM.-HYDROBIOL. 1988. vol. 16, no. 2, pp. 157-163
LA: English
ER: F (Freshwater)
AB: Denitrification is studied in sediments from two areas of the River Butron, Spain, which represent different situations with respect to their degree of pollution. In all the samples analysed denitrification follows a kinetic type Michaelis-Menten with respect to nitrate. V sub(max), K sub(m) and number of denitrifiers are clearly superior in the polluted are when compared to the cleaner area, indicating an advantage given that denitrification suggests an alternative pathway for breaking down organic matter with low levels of dissolved oxygen. By comparison between K sub(m) and natural nitrate concentration values we find that v follows a first order kinetic depending directly on the nitrate concentration. v also presents higher values in the area of the river where the entry of sewage is taking place than in the cleaner area.
AN: 2061943
1396 of 1521
TI: Nitrogen biogeochemistry in an unpolluted estuary: The importance of benthic denitrification.
AU: Seitzinger,-S.P.
AF: Patrick Cent. Environ. Res., Acad. Nat. Sci., Philadelphia, PA 19103, USA
SO: MAR.-ECOL.-PROG.-SER.. 1987. vol. 41, no. 2, pp. 177-186
NT: Incl. 45 ref.
LA: English
ER: B (Brackish)
AB: Denitrification rates (N sub(2) production), and benthic ammonium, nitrate and oxygen fluxes were measured along a salinity gradient in Ochlockonee Bay (Florida, USA) over an annual cycle. The major source of NO sub(3)@)u- or NO sub(2)@)u- for denitrification is from nitrification in the sediments not diffusion of NO sub(3)@)u- or NO sub(2)@)u- from the overlying water. Denitrification is a major removal mechanism for nitrogen in Ochlockonee Bay, and removes, on an annual basis, an amount of nitrogen equivalent to 54% of the river input of dissolved inorganic nitrogen. N sub(2)O fluxes were small compared to N sub(2) fluxes; N sub(2)O/N sub(2) ratios in March were less than 0.01.
AN: 2060966
1397 of 1521
TI: Regional distribution and geobiochemical significance of concentration patterns of non-volatile organochlorine compounds in dabs (Limanda limanda ) of the southern and central North Sea.
OT: Regionale Verteilung und geobiochemische Bedeutung der Konzentrationsmuster schwerfluechtiger Organochlorverbindungen in Klieschen (Limanda limanda ) der suedlichen und zentralen Nordsee
AU: Buether,-H.
AF: Bundesforschungsanst. Fisch., Inst. Kuesten- und Binnenfisch., Aussenstelle Cuxhaven, Niedersachsenstr., D-2190 Cuxhaven, FRG
CA: Bremen Univ. (FRG). Fachber. Biologie/Chemie
SO: VEROEFF.-INST.-KUEST.-BINNENFISCH. 1988. no. 99, 237 pp
NT: Bibliogr.: 282 ref. Diss. (Dr. rer. nat.).
LA: German
ER: M (Marine)
AB: Regional distribution and geobiochemical significance of concentration patterns of non-volatile organochlorine compounds in dabs (Limanda limanda ) of the southern and central North Sea. In December 1984, January and May 1985 and January 1986 at a total of 109 stations in the German Bight and the southern and central North Sea dabs Limanda limanda were caught for an investigation of the regional distribution of chlorinated organic compounds such as PCBs, Sigma DDT, HCB, alpha -HCH and lindane. For comparison the contamination of cod (Gadus morhua ), plaice (Pleuronectes platessa ), flounder (Platichthys flesus ) and blue mussels (Mytilus edulis ) was determined.
AN: 2054119
1398 of 1521
TI: RRS Discovery Cruise 175, 18 June-15 July 1988. Investigations of the flux of biogeochemical material and its transformation by the midwater biota at the BIOTRANS (c. 47 degree N, 20 degree W).
AU: Pugh,-P.R.
AF: Inst. Oceanogr. Sci., Deacon Lab., Wormley, Godalming, Surrey GU8 5UB, UK
SO: CRUISE-REP.-INST.-OCEANOGR.-SCI.,-DEACON-LAB. 1988. no. 204, 72 pp
LA: English
ER: M (Marine)
AB: Discovery cruise 175 can be considered as a prelude to and test run for parts of the BOFS (Biogeochemical Ocean Flux Studies) sampling programme. It encompassed a multidisciplinary approach to investigation of the flux of biogeochemical material and its transformation by the midwater biota. The BIOTRANS site (ca. 47 degree N, 20 degree W) was chosen as it will be one of the primary sampling site during the BOFS experiment. Attempts were made to assess a) the sedimentation rates of particles using sediment traps; b) the vertical distribution of particles (8-256 mu m), using the in situ particle counting system FIDO; c) the vertical distribution and diel migrations of plankton and micronekton; d) the vertical distribution (0-300 m) of bacteria, phytoplankton and their pigments, and nutrients in conjunction with measurements of the physical structure of the water column; e) flagellate grazing potential.
AN: 2054076
1399 of 1521
TI: Biogeochemical cycling of organic carbon in the sediments of the Grote Rug reservoir.
AU: Adams,-D.D.; Eck,-G.T.M.-Van
AF: Cent. Earth and Environ. Sci., State Univ. New York, Plattsburgh, NY 12901, USA
CO: 3. International Workshop on the Measurement of Microbial Activities in the Carbon Cycle in Aquatic Ecosystems, Utrecht (Netherlands), 18 Aug 1986
SO: PROCEEDINGS-OF-THE-THIRD-INTERNATIONAL-WORKSHOP-ON-THE-MEASUREMENT-OF-MICROBIAL-ACTIVITIES-IN-THE-CARBON-CYCLE-IN-AQUATIC-ECOSYSTEMS. Cappenberg,-T.E.;Steenbergen,-C.L.M.-eds. 1988. no. 31 pp. 319-330
ST: ERGEB.-LIMNOL.-ADV.-LIMNOL. no. 31
LA: English
ER: F (Freshwater)
AB: In situ measurements of electron acceptors were utilized to construct an organic carbon decomposition budget for the upper 30 cm of sediments in the "Grote Rug", an oligotrophic freshwater reservoir near Dordrecht, the Netherlands. From the 80 g/m super(2)/y total organic carbon deposited to the sediments, 60% was decomposed aerobically with the remainder fueling anaerobic metabolism (15%) or being permanently buried (25%). The major anaerobic processes accounting for carbon mineralization were sulfate reduction and methanogenesis, in approximate equal proportions. Denitrification was not important to carbon recycling.
AN: 2051160
1400 of 1521
TI: The biogeochemistry of molecular hydrogen in sulfate-reducing sediments.
AU: Novelli,-P.C.
CA: State Univ. of New York, Stony Brook (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1988. vol. 49, no. 6, 253 pp
NT: Diss. Ph.D.: Order No.: DA8812798.
LA: English
AB: Concentrations of molecular hydrogen (H sub(2)) have been measured using an equilibration-vacuum transfer method coupled to mercuric oxide reduction. In hemipelagic sediments (Eastern Tropical North Pacific) and bioturbated sediments (Princess Louisa Inlet, BC, and Buzzards Bay, MA) hydrogen levels were lowest in surface sediments and increased with depth. Experiments using sulfate-reducing sediments have shown that hydrogen oxidation can be coupled to nitrate reduction. Apparent hydrogen production rates were determined in laboratory incubations of sediments amended with inhibitors of sulfate reduction and methanogenesis. The results show that hydrogen production is, in part, a function of the type of organic matter being degraded.
AN: 2050685
1401 of 1521
TI: The early diagenesis of transition metals in nearshore sediments.
AU: Shaw,-T.J.
CA: California Univ., San Diego (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1988. vol. 49, no. 6, 180 pp
NT: Diss. Ph.D.: Order No.: DA8811867.
LA: English
ER: M (Marine)
AB: Transition metal concentrations in sediments can be used to predict the environment of deposition at the time of burial. In order to understand the relationship between environmental conditions and metal burial this study identifies factors important in the transport and burial of metals during the sediment early diagenesis. Sediment cores from five different depositional environments in the Southern California Borderland were studied. Evidence is presented which suggests that at least some detrital nickel, copper, chromium, molybdenum, and vanadium is associated with biogenic material. A model which predicts oxygen consumption as a function of organic carbon input was applied to the most oxic cores.
AN: 2050682
1402 of 1521
TI: Metabolism of methylated sulfur compounds in anoxic salt marsh sediments.
AU: Kiene,-R.P.
CA: State Univ. of New York, Stony Brook (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1987. vol. 48, no. 2, 269 pp
NT: Diss. Ph.D.: Order No.: FAD DA8710926.
LA: English
ER: B (Brackish)
AB: The microbial metabolism of methylated reduced sulfur compounds was examined in anoxic salt marsh sediments. Methionine and dimethyl-sulfoniopropionate (DMSP) were identified as potential precursors of volatile organic sulfur compounds. Microbial hydrolysis of sulfur-carbon linkages resulted in the liberation of methane thiol (MSH) and dimethyl sulfide (DMS) from methionine and DMSP respectively. Ultimately, methylated sulfur compounds were consumed by biological processes and converted to mineralized end products such as CO sub(2), CH sub(4) and H sub(2)S. The metabolism of methylated sulfur compounds in sediments may reduce the emissions of these volatile compounds to the water column and the atmosphere.
AN: 2047034
1403 of 1521
TI: Mechanisms controlling silica flux from sediments and implications for the biogeochemical cycling of silica in Lake Michigan.
AU: Conley,-D.J.
CA: Michigan Univ., Ann Arbor (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1987. vol. 48, no. 2, 113 pp
NT: Diss. Ph.D.: Order No.: FAD DA8712089.
LA: English
ER: F (Freshwater)
AB: Mechanisms governing the benthic regeneration of biogenic silica (BSi) in Lake Michigan were investigated. The impact of sediment fluxes of dissolved silica (Si) and soluble reactive phosphorus (SRP) on the biogeochemical cycling of Si and phosphorus were examined. Si fluxes measured directly by incubation of intact sediment cores were 1 to 10 times greater than Si fluxes calculated from pore water Si concentration gradients. Manipulation experiments confirmed the importance of a surface flocculent layer to measured Si fluxes. Differences in turnover rates of Si and P calculated for Lake Michigan provide the mechanism for the rapid Si depletion previously documented in the Great Lakes.
AN: 2046044
1404 of 1521
TI: Biogeochemical processes of incorporation and transformation of super(14)C labelled fulvic acid, humic acid and simple organic molecules at the sediment-water interface (submarine canyon of the NW Mediterranean).
AU: Buscail,-R.; Gadel,-F.
AF: Lab. Sedimentol. et Geochim. Mar., Univ. Perpignan, France
CO: 3. Int. Meet. of the International Humic Substances Society, Oslo (Norway), 4-8 Aug 1986
SO: ADVANCES-IN-HUMIC-SUBSTANCES-RESEARCH. Becher,-G.-ed. 1987. vol. 62 pp. 409-412
ST: SCI.-TOTAL-ENVIRON. vol. 62
LA: English
ER: M (Marine)
AB: The input of organic compounds at the marine water-sediment interface was simulated by the injection of 14C labelled raygrass fulvic and humic acids and glutamic acid in the overlying water of three identically preserved interfaces. After incubations of 6 days under in situ conditions (13 degree C, oxidizing conditions), separation of the resulting products are carried out by successive chemical extractions. They correspond to the relative importance of biological (respiration, assimilation) and geochemical (condensation in geopolymers and adsorption) processes. Two experiments have showed predominance of biological processes (with super(14)C fulvic and glutamic acids), while in the case of super(14)C humic acid, incorporation in sediment and geochemical processes are more important.
AN: 2043142
1405 of 1521
TI: Inorganic and organic ligand binding of lead and cadmium and resultant implications for bioavailability.
AU: Campbell,-J.H.; Evans,-R.D.
CO: 3. Int. Meet. of the International Humic Substances Society, Oslo (Norway), 4-8 Aug 1986
SO: ADVANCES-IN-HUMIC-SUBSTANCES-RESEARCH. Becher,-G.-ed. 1987. vol. 62 pp. 219-226
ST: SCI.-TOTAL-ENVIRON. vol. 62
LA: English
ER: F (Freshwater)
AN: 2043077
1406 of 1521
TI: Biogeochemistry of organic matter deposition and diagenesis in Bering-Chukchi and Gulf of Mexico sediments.
AU: Caughey,-M.E.
CA: Texas Univ., Austin (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1988. vol. 49, no. 6, 162 pp
NT: Diss.: Ph.D. Order No.: DA8816418.
LA: English
ER: M (Marine)
AB: The research described focused on two biogeochemical processes: (1) the formation of super(13)C-depleted carbonates in sediments influenced by natural, submarine hydrocarbon seepage, and (2) the distribution, deposition and early diagenesis of marine and terrigenous organic matter in continental shelf sediments from a sub-arctic and a sub-tropical environment. Analyses of suites of sediment grab samples from the continental shelves of the eastern Bering and Chukchi Seas and the northwestern Gulf of Mexico provide insights into patterns of organic matter distribution in shallow marine environments.
AN: 2040317
1407 of 1521
TI: The distribution and molecular characterization of dissolved DNA in aquatic environments.
AU: DeFlaun,-M.F.
CA: South Florida Univ., Tampa (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1988. vol. 49, no. 6, 144 pp
NT: Diss. Ph.D.: Order No.: DA8806187.
LA: English
AB: The distribution of dissolved DNA in oceanic, estuarine and freshwater environments in southwest Florida and the Gulf of Mexico was determined. Oceanic concentrations of extracellular DNA ranged from 0.2 to 19 mu g/l. Estuarine concentrations, followed the seasonal trend in water temperature. Diel studies indicated little variation in dissolved DNA concentrations in offshore environments, while variations in the estuary were significant, with maximum concentrations in nighttime samples. These results indicated that dissolved DNA is in a size range sufficient to contain gene sequences, which may be important in natural transformation of microbial populations.
AN: 2040263
1408 of 1521
TI: Carbon flow in an agricultural stream ecosystem.
AU: Robertson,-T.E.
CA: Iowa State Univ., Ames (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1988. vol. 49, no. 2, 165 pp
NT: Diss. Ph.D.: Order No.: DA8805133.
LA: English
ER: F (Freshwater)
AB: The ecological structure and functioning of agriculturally impacted streams, as relates to carbon dynamics, as well as the functional relationships of the invertebrate community to their food source, is unknown. The purpose of this study at Big Creek, Iowa, was to quantify the annual flow of carbon through its various compartments and to relate these carbon sources to the structuring of the invertebrate community in this second order, agriculturally impacted stream. Dissolved organic matter (fraction < 0.45 u) is the dominant fraction, by weight, in the study section. Of the daily terrestrial production of 48,528 kg C day super(-1), 4% or 1851 kg C day super(-1) is allochthonous inputs to upper Big Creek of which 99% is transported out of the upper section.
AN: 2034267
1409 of 1521
TI: Recent biogenic sedimentation on the Antarctic continental margin.
AU: Leventer,-A.R.
CA: Rice Univ., Houston, TX (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1989. vol. 49, no. 10, 249 pp
NT: Diss. Ph.D.: Order No.: DA8900255.
LA: English
ER: M (Marine)
AB: Floral and geochemical analyses were conducted on sinking and suspended particulate matter, and on sea ice and recent sediment samples from the northwestern Weddell Sea--northern Antarctic Peninsula area, and McMurdo Sound, in the southwestern Ross Sea. Data from McMurdo Sound reveal that although large numbers of diatom frustules dissolve within the upper water column the decrease in silica mass flux is much smaller. At mid-water depths, increases in the absolute flux of Nitzschia curta and Thalassiosira spp. indicate the influence of lateral advection. Within a near-bottom nepheloid layer additional dissolution occurs. Dilution and preferential dissolution is responsible for production of a surface sediment assemblage dominated by Thalassiosira spp. and Nitzschia curta .
AN: 2034219
1410 of 1521
TI: Fluxes of particulate protein amino acids in Funka Bay in autumn.
AU: Yanada,-M.; Maita,-Y.
AF: Lab. Mar. Chem., Fac. Fish., Hokkaido Univ., Hakodate, Japan
SO: BULL.-FAC.-FISH.-HOKKAIDO-UNIV. 1986. vol. 37, no. 2, pp. 134-143
LA: Japanese
ER: M (Marine)
AB: The fluxes of particulate protein amino acids were examined in three size fractions (> 690 mu m, 350 similar to 690 mu m, and < 350 mu m) of sinking particles in a sediment trap deployed at a depth of 74 m in Funka Bay from August to October. The total flux of amino acids for this period was 135 mg/m super(-2)/day. The fluxes of the amino acids in the three size fractions accounted for 50, 30 and 20% of the total flux, respectively. In the coastal area, the organic materials excreted by zooplankton (e.g. fecal materials and larvacea houses) transported more than 80% of the protein amino acids into the trap at the depth of 74 m. The amino acid content in the three size fractions increased with larger sinking particles.
AN: 2033917
1411 of 1521
TI: Cadmium-113m as a biogeochemical tracer for cadmium in Lake Michigan.
AU: Dunn,-D.L.
CA: Clemson Univ., SC (USA)
SO: DISS.-ABST.-INT.-PT.-B-SCI.-and-ENG. 1988. vol. 49, no. 5, 133 pp
NT: Diss. Ph.D.: Order No.: DA8816265.
LA: English
ER: F (Freshwater)
AB: Cadmium is a toxic trace metal responsible for several debilitating pathological conditions. Antropogenic activity has greatly enhanced environmental cadmium mobility. There has been concern about the fate of cadmium in potable water supplies. The Great Lakes are major sources of freshwater for much of the populated United States and Canada. The Lake Michigan watershed has been sampled for super(113m)Cd. This long-lived metastable isotope of cadmium allowed independent evaluation of cadmium distribution in this dynamic ecosystem. super(113m)Cd analysis was not hampered by contamination or loss. The super(113m)Cd activities confirm the expected semiconservative behavior for cadmium.
AN: 2033703
1412 of 1521
TI: Trace metal studies on the starfish Asterias rubens L. from the Western Baltic Sea.
AU: Bruegmann,-L.; Lange,-D.
AF: Acad. Sci. GDR, Inst. Mar. Res., Rostock-Warnemuende, GDR
SO: CHEM.-ECOL. 1988. vol. 3, no. 4, pp. 295-311
LA: English
ER: M (Marine)
AB: In 1984, 115 samples of the starfish Asterias rubens L. collected in the south-eastern part of Cadet Trench (Mecklenburg Bay/Western Baltic Sea) were analyzed for their contents of a few major (calcium, magnesium) and trace elements (cadmium, copper, iron, mercury, manganese, nickel, lead, selenium and zinc). Distinct differences were found between starfish from different stations, and these are attributed to the composition of the sediments acting as a substrate for their prey (mussels, snails). Except for cadmium, the concentrations of the elements studied all correlated negatively with the diameter and weight of the starfish.
AN: 2030490
1413 of 1521
TI: Mobilization of radiocaesium in pore water of lake sediments.
AU: Comans,-R.N.J.; Middelburg,-J.J.; Zonderhuis,-J.; Woittiez,-J.R.W.; De-Lange,-G.J.; Das,-H.A.; Van-Der-Weijden,-C.H.
AF: Dep. Chem. and Mater. Sci., Netherlands Energy Res. Found. (ECN), P.O. Box 1, 1755 ZG Petten, Netherlands
SO: NATURE. 1989. vol. 339, no. 6223, pp. 367-369
LA: English
ER: F (Freshwater)
AB: The deposition of large amounts of radiocaesium from nuclear weapons testing and from accidents such as Chernobyl has necessitated study of the fate of these long-lived radioisotopes in the natural environment. Radiocaesium can be removed from the water column in lake systems by setting particles and surface sediments. This process reduces its mobility and the risk of assimilation by biota. Nevertheless, there are indications that radiocaesium may be mobilized from lacustrine anoxic sediments. The pore-water data indicate that radiocaesium is returned to the water column and thus becomes available for uptake by aquatic organisms.
AN: 2027012
1414 of 1521
TI: Particulate matter and nutrient distributions in the ice-edge zone of the Weddell Sea: Relationship to hydrography during late summer.
AU: Nelson,-D.M.; Smith,-W.O.,Jr.; Muench,-R.D.; Gordon,-L.I.; Sullivan,-C.W.; Husby,-D.W.
AF: Coll. Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA
SO: DEEP-SEA-RES. 1989. vol. 36, no. 2A, pp. 191-209
LA: English
ER: M (Marine)
AB: Previous estimates of the marginal ice zone's quantitative contribution to biogeochemical cycles and annual productivity in the Southern Ocean may be conservative because of assumptions that phytoplankton blooms are associated only with actively retreating ice edges. Observations during March 1986, near an almost stationary ice edge in the northwestern Weddell Sea, revealed very low geostrophic currents, no appreciable horizontal gradients in temperature or salinity and no significant net melting or freezing in the ice-edge region. In contrast with previous observations in marginal ice zones, the distribution of phytoplankton biomass showed little correlation with the meltwater field; here, significant horizontal biomass gradients occurred in an area where vertical stability was almost uniform laterally and both elevated biomass and diminished nutrient levels extended well below the pycnocline.
AN: 2020833
1415 of 1521
TI: The effect of biological and physical disturbances on the transport of arsenic from contaminated estuarine sediments.
AU: Riedel,-G.F.; Sanders,-J.G.; Osman,-R.W.
AF: Acad. Nat. Sci., Benedict Estuarine Res. Lab., Benedict, MD 20612, USA
SO: ESTUAR.-COAST.-SHELF-SCI. 1987. vol. 25, no. 6, pp. 693-706
LA: English
ER: M (Marine); B (Brackish)
AB: From the distribution of dissolved and solid arsenic species in a contaminated estuarine sediment (Chesapeake Bay) and measured rates of flux of the various arsenic species the authors propose an empirical model for the cycling of arsenic between sediments and water column. The chemical form of arsenic in the sediment was largely determined by the redox state of the sediment. Arsenite was the dominant dissolved and solid species in the deeper reduced sediment, and arsenate was dominant in the oxidized surface layer. Nereis succinea , a burrowing polychaete, affected distribution and flux of arsenic from the sediments by its production of irrigated burrows. Although physical resuspension can produce large pulses of materials from contaminated sediments, continuous biological activity is likely to be more important in the mobilization of contaminants from sediments in many estuarine environments.
AN: 2010770
1416 of 1521
TI: On the biogeochemical characteristics of surface sediments in Chinhae Bay in September 1983.
AU: Yang,-D.B.; Hong,-J.S.
AF: Korea Ocean Res. Dev. Inst., Ansan, P.O. Box 29, Seoul 425-600, Korea
SO: BULL.-KOREAN-FISH.-SOC. 1988. vol. 21, no. 4, pp. 195-205
LA: English
ER: M (Marine)
AB: Distribution of organic materials in the surface sediments was investigated in September 1983 in Chinhae Bay system. Bottom waters containing less than lml/l of dissolved oxygen were found in Masan Bay, and in part of Kohyonsong Bay and Wonmunpo Bay. Organic carbon content in the surface sediments of Masan Bay was about 25 mg/g and it decreased with increasing distance from the inner Masan Bay. Mean organic carbon contents in Wonmumpo Bay and Kohyonsong Bay were 26.48 and 31.39 mg/g, respectively, which are higher values than those in Masan Bay where large amount of domestic and industrial wastewaters are discharged into the surface water and extensive phytoplankton bloom occurs almost year round. Mean organic nitrogen and pheophytin contents were also the highest in Kohyonsong Bay.
AN: 1993555
1417 of 1521
TI: Comparison of torbanites of various origins and evolutionary stages. Bacterial contribution to their formation. Cause of the lack of botryococcane in bitumens.
AU: Derenne,-S.; Largeau,-C.; Casadevall,-E.; Connan,-J.
AF: Lab. Chim. Bioorg. et Org. Phys., UA CNRS 456, E.N.S.C.P., 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France
SO: ORG.-GEOCHEM. 1988. vol. 12, no. 1, pp. 43-59
LA: English
ER: M (Marine)
AB: Torbanites are kerogen-rich deposits chiefly composed of the remains of a colonial alga with a morphology similar to the one of extant Botryococcus braunii . The structure of a torbanite within the oil window (BJ 248) was examined by FTIR and solid state super(13)C NMR on bitumen-free, unheated material and pyrolysis residues, with identification of the hydrocarbons and fatty acids released on 400 degree C pyrolysis. Maturation entails a partial oxygen elimination, an extensive aromatization, a relative increase in tertiary aliphatic carbons and an important release of hydrocarbon chains. The absence of botryococcane in the bitumen of the twelve torbanites examined may reflect, either a complete removal of botryococcane precursors under partly oxic conditions of sedimentation, or, in some bitumens, a primary property linked to torbanite formation from the A race. Non-occurrence of botryococcane in crude oils cannot be used as a definite proof of the lack of Botryococcus contribution in source rocks.
AN: 1992509
1418 of 1521
TI: Cadmium and mercury in coastal waters: Biogeochemistry and the use of Mytilus as a quantitative indicator.
OT: Le cadmium et le mercure en milieu cotier: Biogeochimie et utilisation du genre Mytilus comme indicateur quantitatif
AU: Cossa,-D.
CA: Univ. Paris-6 (France)
SO: PARIS-FRANCE-UNIVERSITE-PIERRE-ET-MARIE-CURIE 1987. 383 pp
NT: Thesis (Sciences).
LA: French
ER: M (Marine)
AB: Calcium and mercury are two elements whose biogeochemical behaviour is still poorly understood. The present work is intended to contribute to the knowledge of the behavior and the fluxes of these two metals in a coastal area -- the Estuary and Gulf of St. Lawrence. Contamination monitoring by optimizing the use of Mytilus spp. as a tool is suggested. The work is therefore divided into two parts. The first is concerned with the biogeochemical aspect, the second considers the use of the genus Mytilus as a quantitative biological indicator.
AN: 1991037
1419 of 1521
TI: Analytical models of lake phosphorus dynamics.
AU: Havis,-R.N.
AF: USDA-Agric. Res. Serv., Univ. Missouri, Columbia, MO 65201, USA
CA: North American Lake Management Soc., Arlington, VA (USA)
CO: 8. Annual International Symposium on Lake and Watershed Management, St. Louis, MO (USA), 15-18 Nov 1988
SO: 8.-ANNUAL-INTERNATIONAL-SYMPOSIUM-ON-LAKE-AND-WATERSHED-MANAGEMENT. 1988. p. 48
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Lake trophic state can often be related to lake water phosphorus concentration. Accordingly, steady state models such as Vollenweider's P loading versus mean depth criterion axes are useful for prediction of steady trophic state conditions. This paper presents analytical mathematical models that consider lake bottom P cycling to predict the dynamic response of lake water P concentration in completely mixed systems to changes in external P loading. An exact solution to the lake model used annual average variables to simulate the recovery of a small lake in western Massachusetts. Simplified solutions were found using approximation techniques. Simulations from the approximate and exact models corresponded well, using variable values typical for the case study lake. Further model testing showed differences in predictions that were explained by the assumptions used to derive the approximate models.
AN: 1985698
1420 of 1521
TI: (Aquatic biology. Methods and techniques.).
OT: Biologie des eaux. Methodes et techniques
AU: Champiat,-D.; Larpent,-J.-P.
AF: Cent. Natl. Mach. Agric., Genie Rural Eaux For., 69000 Lyon, France
SO: PARIS-FRANCE-MASSON 1988. 374 pp
LA: French
ER: F (Freshwater)
AB: This book consists of two parts: one theoretical and the other practical. The first part deals with brackishwater organisms and biogeochemical cycling of major elements (C, N, Fe, Mn, P, S), pollution by sewage effluents, aerobic and anaerobic water purification (activated sludge or methanization). The authors study indicator bacteria, parasitology and disinfection problems. The second part is a technical data set for teaching and laboratory purposes.
AN: 1985306
1421 of 1521
TI: Anoxygenic phototrophic bacteria and sulfate-reducing bacteria in coastal lagoons.
OT: Role des bacteries phototrophes et des bacteries sulfato-reductrices dans les milieux lagunaires
AU: Caumette,-P.
CA: Aix-Marseille 3 Univ. (France)
SO: ETUD.-THESES-INST.-FR.-RECH.-SCI.-DEV.-COOP. PARIS-FRANCE-ORSTOM 1988. 304 pp
NT: Thesis (Sciences Naturelles).
LA: French
ER: B (Brackish)
AB: The occurrence and development of phototrophic bacteria and sulfate reducing bacteria, their role in the sulfur cycle and their biomass production is discussed. The study area is located in shallow and stratified lagoons in temperate regions (Mediterranean and Atlantic French coast) and Tropical regions "Atlantic coast of Ivory Coast in West Africa). Systematics of phototrophic bacteria, methods of physical, chemical and bacteriological analysis, and trophic relations between phototrophic bacteria and copepods are also described.
AN: 1985023
1422 of 1521
TI: The significance of malathion on the phosphorus dynamics of an acid bog lake.
AU: Jones,-K.L.
AF: Dep. Biol. Sci., Kent State Univ., Kent, OH 44242, USA
CO: 97. Annu. Meet. Ohio Acad. of Sci., Newark, OH (USA), 29 Apr 1988
SO: 97th-ANNUAL-MEETING:-THE-OHIO-ACADEMY-OF-SCIENCE.-APRIL-29-30,-MAY-1,-1988. Meserve,-L.-ed. 1988. vol. 88, no. 2 pp. 46-47
ST: OHIO-J.-SCI. vol. 88, no. 2
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: Phosphorus availability limits growth of zooplankton and phytoplankton in Triangle Lake, an acid bog located in Portage County, Ohio. This study examined the effects of malathion, an organophosphorus insecticide, on phosphate uptake by native microorganisms, and release rate of phosphate from dissolved organic phosphorus compounds (DOP), in surface waters of this lake. The results indicate that low concentrations of malathion, such as that which can be found in natural systems, may adversely affect phosphorus-limited aquatic communities.
AN: 1984049
1423 of 1521
TI: The dissolved organic phosphorus (DOP) composition of an acid bog lake in Portage County, OH.
AU: Edinger,-A.C.; Heath,-R.T.
AF: Dep. Biol. Sci., Kent State Univ., Kent, OH 44243, USA
CO: 97. Annu. Meet. Ohio Acad. of Sci., Newark, OH (USA), 29 Apr 1988
SO: 97th-ANNUAL-MEETING:-THE-OHIO-ACADEMY-OF-SCIENCE.-APRIL-29-30,-MAY-1,-1988. Meserve,-L.-ed. 1988. vol. 88, no. 2 p. 45
ST: OHIO-J.-SCI. vol. 88, no. 2
NT: Summary only.
LA: English
ER: F (Freshwater)
AB: The composition of the dissolved organic phosphorus (DOP) pool in surface water from Triangle Bog Lake, a glacial acid bog, was examined seasonally. The purpose of this work was to determine the composition of rapidly labelled DOP using radiometric procedures. Freshly collected 5 ml water samples, radiolabelled with carrier-free 32P orthophosphate and fractionated by Sephadex G-25, chromatographed as did orthophosphate in a control experiment. Radiolabelled water, both centrifuged (27,000 g for 15 minutes) and uncentrifuged, incubated for 24 hours at ambient temperature and run through the Sephadex column, indicated that the 32P orthophosphate was associated with high molecular weight compounds.
AN: 1983542
1424 of 1521
TI: Organic matter dynamics in four seasonally flooded forest communities of the Dismal Swamp.
AU: Megonigal,-J.P.; Day,-F.P.,Jr.
AF: Div. Wetlands Ecol., Savannah River Ecol. Lab., Drawer E, Aiken, SC 29801, USA
SO: AM.-J.-BOT. 1988. vol. 75, no. 9, pp. 1334-1343
LA: English
ER: F (Freshwater)
AB: Budgets of organic matter dynamics for plant communities of the Great Dismal Swamp were developed to summarize an extensive data base, determine patterns of biomass allocation, transfer and accumulation, and make comparisons with other forested wetlands. Aboveground net primary production on the flooded sites (1,050-1,176 g m super(-2)/yr) was significantly greater than on a rarely flooded site (831 g m super(-2)/yr). Estimates of belowground net primary production were comparable to aboveground production on flooded sites (824-1,221 gm super(-2)/yr). However, productivity was nearly three times greater belowground than aboveground on the rarely flooded site (2,256 g m super(-2)/yr). Aboveground productivity in Dismal Swamp forests is relatively high compared to other forested wetlands.
AN: 1980856
1425 of 1521
TI: A numerical scheme for solving a stream nutrient model.
AU: Hearne,-J.W.; Wake,-G.C.
AF: Dep. Math. and Stat., Massey Univ., Palmerston North, New Zealand
SO: APPL.-MATH.-MODEL. 1989. vol. 13, no. 3, pp. 155-159
LA: English
ER: F (Freshwater)
AB: Water quality models have often neglected to incorporate the feedback effects of nutrient uptake and release by riparian vegetation. When this increasingly important effect is incorporated, the numerical solution methods used for standard models are no longer applicable. Such a model comprises a coupled system of first-order nonlinear partial differential equations, the characteristics of which are different and (in one case) depend on the state variables. This paper provides a method of numerical solution which can be used by practitioners in this and other applications. An illustrative example is given.
AN: 1972345
1426 of 1521
TI: Biogeochemical cycling in the ocean. Part 1. Introduction to the effects of upwelling along the west coast of North America.
AU: Howe,-J.T.
CA: NASA, Moffett Field, CA (USA). Ames Research Cent
SO: NASA-TECH.-MEMO. 1986. 39 pp
NT: NTIS Order No.: N88-15349/9/GAR. NAS 1.15:88230, A-86181.
RN: NASA-TM-88230 (NASATM88230)
LA: English
ER: M (Marine)
AB: Coastal upwelling is examined as it relates to the cycling of chemical species in coastal waters along the west coast of North America. The temporal and spatial features of upwelling phenomena in a Eastern boundary regions of the North Pacific Ocean are presented and discussed in terms of upwelling episodes. Climate conditions affecting upwelling include: thermal effects, wind-induced shear stress which moves surface layers, and the curl of the wind stress vector which is thought to affect the extent and nature of upwelling and the formation of offshore convergent downwelling fronts. These effects and the interaction of sunlight and upwelled nutrients which result in a biological bloom in surface waters is modeled analytically. The roles of biological and chemical species, including the effects of predation, are discussed in that context, and relevant remote sensing and in situ observations are presented. Climatological, oceanographic, biological, physical, chemical events, and processes that pertain to biogeochemical cycling are presented and described.
AN: 1958918
1427 of 1521
TI: The excretion of phosphate and ammonia from microcrustaceans and its vertical and seasonal distribution at an offshore station in Lake Michigan.
AU: Busch,-J.L.; Brooks,-A.S.
AF: Cent. Great Lakes Stud., Univ. Wisconsin, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA
CO: (23.) Congress in New Zealand, (Hamilton (New Zealand)), 8 Feb 1987
SO: CONGRESS-IN-NEW-ZEALAND-1987.-PROCEEDINGS. Sladecek,-V.-ed. 1988. vol. 23, no. 1 pp. 366-375
ST: VERH.-INT.-VER.-THEOR.-ANGEW.-LIMNOL.-PROC.-INT.-ASSOC.-THEOR.-APPL.-LIMNOL.-TRAV.-ASSOC.-INT.-LIMNOL.-THEOR.-APPL. vol. 23, no. 1
NT: Incl. 31 ref.
LA: English
ER: F (Freshwater)
AB: The zooplankton contribution of phosphate and ammonia in a Lake Michigan water column was estimated, vertical and temporal variation in this input was observed and the percentage contribution of this nutrient source was quantified. For discrete depths throughout the water column, the estimated contribution of zooplankton to the daily nutrient budget was less than 1 to 100% for PO sub(4) and 1 to 51% for NH sub(3). The results showed that throughout the season, the release of nutrients below the thermocline was insignificant. The highest percentages of nutrient excretion that were computed were for metalimnetic waters (10-15 m). There is evidence which indicates that zooplankton not only enhance nutrient availability at certain times of the year but that they also play a major role in determining the succession of algal species.
AN: 1957035
1428 of 1521
TI: Factors controlling the biogeochemical cycles of trace elements in fresh and coastal marine waters as revealed by artificial radioisotopes.
AU: Santschi,-P.H.
AF: Dep. Mar. Sci., Texas A&M Univ., Galveston, TX 77553-1675, USA
SO: LIMNOL.-OCEANOGR. 1988. vol. 33, no. 4, pt. 2, pp. 848-866
NT: Special issue: Comparative ecology of freshwater and marine ecosystems.
LA: English
ER: M (Marine); F (Freshwater)
AB: Radionuclides in aquatic ecosystems can provide important insights into the way physical, chemical, biological, and sedimentological processes are coupled into networks to control the transfer of major and trace elements within the waterbody itself and across its boundaries. Examples from artificial radionuclide studies in freshwater (Experimental Lakes Area in Northern Ontario, ELA) and coastal marine ecosystem enclosures (MERL tanks at Narragansett Bay, Rhode Island) show the cycling of selected trace elements across the sediment-water interface as these are influenced by various biogeochemical factors.
AN: 1951906
1429 of 1521
TI: Experimental studies of chemical stressors on whole lake ecosystems.
AU: Schindler,-D.W.
AF: Dep. Fish. and Oceans, Freshwater Inst., 501 University Crescent, Winnipeg, Man. R3T 2N6, Canada
CO: (23.) Congress in New Zealand, (Hamilton (New Zealand)), 8 Feb 1987
SO: CONGRESS-IN-NEW-ZEALAND-1987.-PROCEEDINGS. Sladecek,-V.-ed. 1988. vol. 23, no. 1 pp. 11-41
ST: VERH.-INT.-VER.-THEOR.-ANGEW.-LIMNOL.-PROC.-INT.-ASSOC.-THEOR.-APPL.-LIMNOL.-TRAV.-ASSOC.-INT.-LIMNOL.-THEOR.-APPL. vol. 23, no. 1
NT: Incl. 118 ref.
LA: English
ER: F (Freshwater)
AB: The earliest work at the Experiental Lakes Area (ELA) in Ontario, Canada in 1969, was a logical extension of earlier studies, focusing primarily the algal production associated with eutrophication. Over the years, the studies have broadened to include community changes, whole ecosystem processes and interactions of lakes with their watersheds and airsheds. Simple monitoring methods were used in the early experimental additions of nutrients and other chemicals to lakes. Lake 227, fertilized with N:P at 14:1 by weight, had produced algal blooms consisting primarily of chlorophytes, while Lake 226, with low rates of fertilization but an N:P ratio of 5:1, consistently produced blooms of nitrogen-fixing cyanophytes. In the mid-1970's the effect of acidification on the metabolism and nutrient cycles of Lake 223 was examined. Experiments on the changes in the biotic community, eutrophication, paleolimnological calibrations, biogeochemical cycles and some small scale and mesocosm experiments followed.
AN: 1948112
1430 of 1521
TI: Composition and bacterial utilization of free amino acids in tropical mangrove sediments.
AU: Stanley,-S.O.; Boto,-K.G.; Alongi,-D.M.; Gillan,-F.T.
AF: Dep. Sea Fish., 23 Old Wharf, Hobart, Tas. 7000, Australia
SO: MAR.-CHEM. 1987. vol. 22, no. 1, pp. 13-30
LA: English
ER: M (Marine)
AB: The composition and bacterial utilization of dissolved free amino acids in tropical mangrove sediments was examined. Amino acid concentrations and composition were similar to that of other organic-rich, anaerobic sediments with lowest and highest concentrations in the low and mid intertidal zones, respectively. The non-protein amino acid, beta -glutamic acid, rarely reported in previous studies, was found as a major component of the interstitial pool. Intracellular amino acids from some cultured strains of sulphate-reducing bacteria showed the presence of beta -glutamic acid as a major cellular constituent suggesting that these bacteria may be a source of this amino acid in mangrove pore waters. In high intertidal sediments, bacterial growth rates ( mu ) correlated significantly with total DFAA concentrations with depth. These experiments suggest that bacterial population in surface sediments are capable of utilizing all of the amino acid flux to the sediment-water interface in tropical mangroves.
AN: 1943979
1431 of 1521
TI: Dimethyl sulfide production during natural phytoplanktonic blooms.
AU: Nguyen,-B.C.; Belviso,-S.; Mihalopoulos,-N.; Gostan,-J.; Nival,-P.
AF: Cent. Faibles Radioact., Lab. Mixte CNRS-CEA, 91190 Gif-sur-Yvette, France
SO: MAR.-CHEM. 1988. vol. 24, no. 2, pp. 133-141
LA: English
ER: M (Marine)
AB: Dimethyl sulfide (DMS), produced by biological activity in seawater, is the principal gaseous form of sulfur released to the atmosphere by the ocean and plays an important part in the biogeochemical sulfur cycle. The production of DMS in seawater tanks has been quantified during phytoplankton bloom simulations for the growth and senescence phases of biomass. This gas production during the senescence phase is 7-26 times higher than during the growth phase. Thus, DMS production by the senescence process could be one of the major mechanisms for the generation of DMS in seawater.
AN: 1943174
1432 of 1521
TI: Preliminary estimations of the flow of certain trace metals in the oyster Crassostrea gigas (Thunberg).
OT: Premieres estimations des flux de quelques elements metalliques chez l'huitre Crassostrea gigas (Thunberg)
AU: Amiard,-J.C.
AF: Cent. Dosage Elem. Traces, Univ. Nantes, 1, rue Gaston Veil, 44035 Nantes Cedex, France
SO: J.-RECH.-OCEANOGR. 1987. vol. 12, no. 3-4, pp. 81-84
LA: French
ER: M (Marine)
AB: Most studies on biogeochemical cycles concentrate on the water, sediment and suspended matter compartments and do not mention the biological compartment. This is the case when the zinc content in oysters is higher than in the surrounding water or the seston and is equal to that of the oxygenated sediment. This paper discusses the results of an assessment of the metal contents found in the oyster Crassostrea gigas .
AN: 1937161
1433 of 1521
TI: Sensitivity of climate and atmospheric CO sub(2) to deep-ocean and shallow-ocean carbonate burial.
AU: Volk,-T.
AF: Earth Syst. Group, Dep. Appl. Sci., New York Univ., 26 Stuyvesant St., New York, NY 10003, USA
SO: NATURE. 1989. vol. 337, no. 6208, pp. 637-640
LA: English
ER: M (Marine)
AB: Previous models of physical and biogeochemical controls of the evolution of atmospheric CO sub(2) and climate over hundreds of millions of years have neglected the effect of variations in the balance between shallow-ocean and deep-ocean carbonate deposition. A model of the carbonate-silicate geochemical cycle that distinguishes carbonate masses produced by the two types of burial shows that reasonable increases in deep-ocean burial could produce substantial warmings over a few hundred million years. Without the habitation of the open ocean by plankton such as forminifera and coccolithophores, today's climate would be substantially colder.
AN: 1931843
1434 of 1521
TI: Rate of production, dissolution and accumulation of biogenic solids in the ocean.
AU: Arrhenius,-G.
AF: Scripps Inst. Oceanogr., Univ. California at San Diego, La Jolla, CA 92093-0220, USA
CO: 2. Hans Pettersson Series of Symposia in Oceanography: Southern Ocean -- The Antarctic: Present and Past, (Sweden), 21-25 Apr 1987
SO: THE-SOUTHERN-OCEAN-THE-ANTARCTIC:-PRESENT-AND-PAST. Olausson,-E.-ed. 1988. vol. 67, no. 1-2 pp. 119-146
ST: PALAEOGEOGR.,-PALAEOCLIMATOL.,-PALAEOECOL. vol. 67, no. 1-2
NT: Special issue.
LA: English
ER: M (Marine)
AB: A permanant record of the changes in rate of upwelling and organic production is generated in the equatorial deep sea sediments, particularly by such biogenic components which are unaffected by secondary dissolution. In order to determine the rates of accumulation of various sedimentary components, a reliable differential measurement of age of the strata must be obtained. Various approaches to this problem are reviewed. Secondary dissolution of calcium carbonate introduces a substantial and variable difference between the dissolution-modified, and hence a priori unknown, rate of deposition on one hand and the rate of accumulation, derivable from the observed concentration, on the other. As a most likely cause of the enhanced state of dissolution of the interglacial carbonate sediments is proposed the lowered rates of biogenic production and deposition, which cause longer exposure of the carbonate microfossils to corrosion in the bioturbated surface layer of the sediment.
AN: 1931028
1435 of 1521
TI: Suspended manganese-rich particles in Kau Bay, Halmahera (eastern Indonesia).
AU: Sloot,-H.A.-Van-Der; Hoede,-D.; Hamburg,-G.; Lange,-G.J.-De; Middelburg,-J.J.; Sophiah,-S.
AF: Netherlands Energy Res. Found., P.O. Box 1, 1755 ZG Petten, Netherlands
SO: MAR.-GEOL. 1988. vol. 82, no. 3-4, pp. 251-259
LA: English
ER: M (Marine)
AB: Suspended particulate matter from Kau Bay, Halmahera has been collected by continuous-flow centrifugation of water samples. On examination by scanning electron microscopy a variety of Mn-rich particles has been found. The most abundant particles are spherical and fairly uniform in size. These particles feature a remarkably uniform cavity on one side and are intimately involved in the geochemical cycling of Mn in Kau Bay. Particles of this form have not been observed before but are likely to occur in comparable open-ocean suboxic water. It is suggested that the formation of microbially mediated Mn particulates is enhanced by the high water temperature, whereas inorganic Mn precipitates are more likely to be found in low-temperature waters.
AN: 1928312
1436 of 1521
TI: Temporal dynamics of an estuary: San Francisco Bay.
AU: Cloern,-J.E.; Nichols,-F.H.-(eds.)
SO: DEV.-HYDROBIOL. 1985. no. 30, 237 pp
LA: English
ER: M (Marine); B (Brackish)
AB: The fourteen papers cover topics from the general physical characteristics of the estuary through a review of many of its chemical and biological communities. The papers address the changes within the various systems over time; time scales usually being seasonal and/or multiyear. After a brief discussion of the estuary's geology and physical oceanography, the papers progress through the biogeochemical basics (nutrients, chemicals, gases), exchanges with the bottom sediments and atmosphere, the benthos, and then up the chain of macroalgae, phytoplankton, zooplankton, shrimp, and fishes, finishing with a wrap-up paper by the editors.
AN: 1923864
1437 of 1521
TI: In situ deep water particle sampler and real-time sensor package with data from the Madeira Abyssal Plain.
AU: Simpson,-W.R.; Gwilliam,-T.J.P.; Lawford,-V.A.; Fasham,-M.J.R.; Lewis,-A.R.
AF: Inst. Oceanogr. Sci., Brook Rd., Wormley, Godalming, Surrey GU8 5UB, UK
SO: DEEP-SEA-RES. 1987. vol. 34, no. 8A, pp. 1477-1497
LA: English
ER: M (Marine)
AB: A deep water particle sampler was designed to measure physical variables in real time and collect particulate and water samples in situ with the view to furthering our understanding of biogeochemical cycles. Profiles of particulate concentration, particle size distribution (10-200 mu m) and temperature against depth are taken on the outward and return casts to a maximum depth of 6000 m. Particle samples are collected by large volume filtration at four depths preselected on the basis of outward cast data. For metal analyses, 1 mu m polycarbonate membranes are used, and glass fibre filters for organic analysis; larger particles may be collected by prefilters of any chosen mesh size. Data presented from the Madeira Abyssal Plain illustrate the function of the instrument and the results are compared to those reported previously.
AN: 1922658
1438 of 1521
TI: Dissolved arsenic in waters of the Cape Basin.
AU: Statham,-P.J.; Burton,-J.D.; Maher,-W.A.
AF: Dep. Oceanogr., Univ. Southampton, Southampton SO9 5NH, UK
SO: DEEP-SEA-RES. 1987. vol. 34, no. 8A, pp. 1353-1359
LA: English
ER: M (Marine)
AB: Measurements of dissolved arsenic have been made on water samples from various depths at six stations in the Cape Basin, using hydride generation and graphite furnace atomic absorption spectrophotometry. Methylated forms of arsenic were not determined under the conditions used. Concentrations in samples from depths shallower than 110 m averaged 19.9 nmol/l (range 17.6-22.8 nmol/l) for all stations. Five stations had water depths greater than about 4000 m, and for these the mean concentration in waters below 110 m was 21.1 nmol/l (range 17.6-23.8 nmol/l super(-1)). The difference in concentration between the upper (< 110 m) and deeper waters was statistically significant. Somewhat higher concentrations of 22.0-27.5 nmol/l were found for water below 110 m at the station nearest shore, whose water depth was about 2200 m. The findings are consistent with the view that the major consequence of the uptake of arsenic by microorganisms is cycling between chemical forms within the euphotic zone and that the flux of arsenic into the deep ocean by transport with particles is minor, relative to the concentration of the element in the oceanic reservoir.
AN: 1922522
1439 of 1521
TI: Iodine speciation in Chesapeake Bay waters.
AU: Luther,-G.W.,III; Cole,-H.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: MAR.-CHEM. 1988. vol. 24, no. 3-4, pp. 315-325
LA: English
ER: B (Brackish)
AB: The authors report on the speciation of iodine in Chesapeake Bay during July 1986. Surface and bottom water samples were taken along the estuary at every 1-2 ppt salinity division. At three locations in the upper bay, samples were taken above, at and below the pycnocline. All samples were analyzed by differential pulse polarography. Iodate was determined directly. Total iodine (including organic forms) was determined by hypochlorite oxidation to iodate. Iodide is defined as the difference between these two analyses. Total iodine appears to be conservative in the estuary. In all samples from the upper bay only reduced forms of iodine were present. Iodine is maintained in its reduced state by biological processes in the surface waters and by a combination of biological and chemical processes in the anoxic bottom waters.
AN: 1918487
1440 of 1521
TI: Dissolved iodine behavior in estuaries along the East Coast of the United States.
AU: Ullman,-W.J.; Luther,-G.W.,III; Aller,-R.C.; Mackin,-J.E.
AF: Coll. Mar. Stud., Univ. Delaware, Lewes, DE 19958, USA
SO: MAR.-CHEM. 1988. vol. 25, no. 2, pp. 95-106
LA: English
ER: B (Brackish)
AB: Previous studies of dissolved iodine behavior in estuaries have shown no evidence of iodine's participation in biogeochemical processes. Three estuaries along the United States' Atlantic coast clearly show the results of iodine reactivity in biological and/or particle processes. Major factors involved in controlling the iodine speciation and distribution in estuaries include: (i) remineralization of iodine-containing organic matter in sediment or anoxic bottom water; (ii) anthropogenic inputs; (iii) resuspension of fine-grained sediments and their associated interstitial water; and (iv) estuarine flow regime and residence time.
AN: 1918362
1441 of 1521
TI: Influences of river flow on the dynamics of phytoplankton production in a partially stratified estuary.
AU: Malone,-T.C.; Crocker,-L.H.; Pike,-S.E.; Wendler,-B.W.
AF: Horn Point Environ. Lab., Univ. Maryland Cent. Environ. and Estuar. Stud., P.O. Box 775, Cambridge, MD 21613, USA
SO: MAR.-ECOL.-PROG.-SER.. 1988. vol. 48, no. 3, pp. 235-249
NT: Incl. 43 ref.
LA: English
ER: B (Brackish)
AB: Seasonal variations in biomass of the phytoplankton of the Chesapeake Bay are correlated with riverine nitrate input while seasonal variations in productivity are correlated with light and temperature. Evidence is presented which suggests that the spring flux of nitrogen from the watershed and the summer productivity maximum are coupled via the accumulation and sedimentation of phytoplankton biomass during spring and subsequent recycling of regenerated nitrogen into the euphotic zone during summer.
AN: 1907754
1442 of 1521
TI: Remote sensing of ocean colour for studies of biological productivity and biochemical cycles.
AU: Holligan,-P.M.; Morel,-A.
CA: Marine Biological Assoc. Plymouth, (UK)
CO: Ocean Color Workshop, Villefranche-sur-Mer (France), 5-6 Nov 1986
SO: OCEAN-COLOR-WORKSHOP. Guyenne,-T.D.-ed. 1987. pp. 19-22
NT: NTIS Order No.: N88-16296/1/GAR. Rec'd 1988.
RN: ESA-SP-1083 (ESASP1083)
LA: English
ER: M (Marine)
AB: The use of ocean color to assess marine biological resources, to study photosynthetic processes (biomass primary production), and to follow biogeochemical cycles (such as CO2 exchange between atmosphere and ocean, and phytoplankton effects on the carbon cycle) is discussed. Aerosol and sediment studies using narrow band visible scanners such as the Coastal Zone Color Scanner to examine materials exchange are mentioned. Steps which must be taken to exploit ocean color imagery in prediction of global environmental change are listed.
AN: 1903774
1443 of 1521
TI: Biogeochemical cycle of mercury species in the marine environment. Final report for the period 1 May 1986-30 March 1987.
AU: Branica,-M.
CA: International Atomic Energy Agency, Vienna (Austria)
SO: 1987. 14 pp
NT: NTIS Order No.: DE88700798/GAR. Rec'd 1988.
RN: IAEA-R-3295-F (IAEAR3295F)
LA: English
ER: M (Marine)
AB: Mercury contamination of the coastal marine environment is an important concern as toxic methylmercury may be formed biogenically in sediments rich in organic matter. The present study was conducted using a sensitive adaptation of Cold Vapour Atomic Absorption Spectrophotometry in which mercury was re-mineralised from a variety of marine matrices, separated and concentrated by ion-exchange chromatography, trapped as an amalgam in gold wool and subsequently re-released by heating to 900 deg. C. Total and organomercury forms were detected respectively by measuring, in the case of seawater, sample extracts treated and untreated with uv light and, in the case of solid matrices, by "total digestion: and HCl extractions.
AN: 1903695
1444 of 1521
TI: The geochemistry of interstitial water for a sediment core from the Indian River Lagoon, Florida.
AU: Gu,-D.; Iricanin,-N.; Trefry,-J.H.
AF: Dep. Oceanogr. and Ocean Eng., Florida Inst. Technol., Melbourne, FL 32901, USA
SO: FLA.-SCI. 1987. vol. 50, no. 2, pp. 99-110
LA: English
ER: B (Brackish)
AB: Chemical results for interstitial water from organic-rich sediments in the Indian River Lagoon, Florida, show a classic picture of biogeochemical reactions in anoxic environments. Interstitial nitrate was depleted throughout the sediment column and complete sulfate reduction was observed at a depth of > 9 cm below the seawater-sediment interface. Interstitial water chlorinity decreased sharply with depth suggesting subsurface occurrence or intrusion of groundwater. Ammonia, phosphate and silica concentrations were high showing significant nutrient regeneration. Dissolved sulfide levels were also high and play a primary role in controlling interstitial water metal concentrations.
AN: 1902990
1445 of 1521
TI: Acid deposition and nutrient leaching from deciduous vegetation and podzolic soils at the Turkey Lakes Watershed.
AU: Foster,-N.W.; Nicolson,-J.A.
AF: Canadian For. Serv., P.O. Box 490, Sault Ste. Marie, Ont. P6A 5M7, Canada
SO: TURKEY-LAKES-WATERSHED-STUDY. 1988. vol. 45, no. suppl. 1 pp. 96-100
ST: CAN.-J.-FISH.-AQUAT.-SCI. vol. 45, no. suppl. 1
LA: English
ER: F (Freshwater)
AB: Mean annual ion concentrations and ion fluxes in precipitation induced by contact with a maple-birch forest and soil were determined for 1981-85 at the Turkey Lakes Watershed (47 degree 03'N, 84 degree 15'W). Neutralization of atmospherically deposited H super(+) was effected by the canopy and mineral soil. Sulphate was an important counterion for K super(+) leached from the vegetation. Acid deposition had a minor impact on the quality of stemflow and forest floor percolate, which were enriched in K super(+) and Ca super(2+) mobilized in association with organic anions. Calcium and Mg super(2+) were leached from the mineral soil in association with SO sub(4) super(2) super(-) and NO sub(3) super(-). Sulphate was derived largely from acid deposition, and NO sub(3) super(-) from both precipitation and nitrification of native soil N.
AN: 1901508
1446 of 1521
TI: Water and chemical budgets for terrestrial basins at the Turkey Lakes Watershed.
AU: Nicolson,-J.A.
AF: Canadian For. Serv., P.O. Box 490, Sault Ste. Marie, Ont. P6A 5M7, Canada
SO: TURKEY-LAKES-WATERSHED-STUDY. 1988. vol. 45, no. suppl. 1 pp. 88-95
ST: CAN.-J.-FISH.-AQUAT.-SCI. vol. 45, no. suppl. 1
LA: English
ER: F (Freshwater)
AB: Twenty terrestrial basins ranging in area from 2.3 to 62.7 ha were monitored in the 1050-ha Turkey Lakes Watershed (TLW) to measure discharge and ion loss from the terrestrial ecosystem and to estimate terrestrial contributions to the main aquatic system. These basins span 400 m of elevation, beginning at 60 m above Lake Superior (183 m a.s.l.). Annual streamflow represented 28-63% of precipitation; 30-60% of the total occurred during springmelt. Precipitation quantity and SO sub(4) super(2) super(-) and NO sub(3) super(-) input were measured at the Atmospheric Environment Service APN station southeast of the TLW; other chemical parameters were measured on samples collected near the main outlet on the west side of the TLW.
AN: 1901501
1447 of 1521
TI: (The role of biosedimentation in the formation of bottom deposits.).
OT: Kvoprosu o roli biosedimentatsii v obrazovanii donnykh otlozhenij
AU: Savenko,-V.S.
AF: Gos. Univ., Moscow, USSR
SO: VODN.-RESUR. 1988. no. 4, pp. 120-129
LA: Russian
AB: Recent data on the granulometric composition of deposits and intensity of actual sedimentation collected at various points of the World Ocean are analysed. Suspended particles of 200-300 mu m are found to settle on bottom according to Stokes law. Physical sedimentation as such does not provide for similarity in the granulometric composition of particulate suspended matter and bottom sediments. The daily filtering potential of zooplankton is 3-6 x 10 super(6) km super(3) of ocean water which results in the separation of about 220-440 billon tons of suspended matter annually, and points to the repeated processing of suspension by zooplankton.
AN: 1880609
1448 of 1521
TI: Binding of manganese by Antarctic Phaeocystis pouchetii and the role of bacteria in its release.
AU: Davidson,-A.T.; Marchant,-H.J.
AF: Antarctic Div., Dep. Sci., Channel Highway, Kingston, Tas. 7150, Australia
SO: MAR.-BIOL. 1987. vol. 95, no. 3, pp. 481-487
NT: Incl. 46 ref.
LA: English
ER: M (Marine)
AB: The growth of Antarctic Phaeocystis pouchetii and associated bacteria in culture, and the binding and release of manganese were investigated using cultures derived from three clonal isolates collected from Prydz Bay, Antarctica, in Nov and Dec 1982. The cultured strains accumulated manganese from the culture medium. The concentration of Mn super(2+) in the alga up to 58 times that of the medium. The Mn super(2+) apparently binds to the mucilage secreted by the cells and gives the alga its characteristic brown colour. Once the growth of P. pouchetii and production of acrylic acid slow, bacterial numbers increase, leading to the solubilization of the mucilage and the release of Mn super(2+).
AN: 1874938
1449 of 1521
TI: Glycolate turnover in the water column of the New York Bight apex.
AU: Edenborn,-H.M.; Litchfield,-C.D.
AF: Oak Ridge Res. Inst., 113 Union Valley Rd., Oak Ridge, TN 37830, USA
SO: MAR.-BIOL. 1987. vol. 95, no. 3, pp. 459-467
NT: Incl. 53 ref.
LA: English
ER: M (Marine)
AB: Heterotrophic bacterial uptake and turnover of glycolate were measured in the water column of the New York Bight apex during four seasonal cruises over almost a one-year period between May 1977 and Mar 1978. Glycolate turnover was most rapid in May and Jul, when primary productivity and estuarine runoff were high. Glycolate flux calculations indicate that the measured rates of glycolate consumption by bacteria always exceeded estimated glycolate production by phytoplankton, except in Mar. This excess may reflect an under-estimation of phytoplankton production or the input of glycolate from other sources, such as estuarine runoff. Glycolate utilization appears to be seasonally important to bacteria in the New York Bight apex, coinciding with fluctuations in phytoplankton primary productivity.
AN: 1874329
1450 of 1521
TI: Acidic deposition impacts mediated by sulfur cycling in a coastal plain forest ecosystem.
AU: Morgan,-M.D.; Good,-R.E.; Spratt,-H.G.,Jr.
AF: Rutgers Univ., Dep. Biol. and Div. Pinelands Res., Camden, NJ 08102, USA
CO: 14. International Botanical Congress, Berlin (FRG), 1987
SO: GEOJOURNAL. 1988. vol. 17, no. 2, pp. 183-187
LA: English
ER: F (Freshwater)
AB: Deposition in the New Jersey Pinelands was very acidic (pH = 4.17) and contained high levels of SO sub(4) super(-) super(2) based on bulk deposition measurements from July 1984-July 1986. Streamwater over the same interval in undisturbed watersheds was less acidic (pH = 4.52) and had proportionately less SO sub(4) super(-) super(2). A preliminary alkalinity budget for undisturbed watersheds suggested that SO sub(4) super(-) super(2) retention within Pinelands watersheds accounted for a large portion of the total alkalinity generated and thereby lessened the impact of acidic deposition on surface waters. The only process capable of explaining the retention of SO sub(4) super(-2) was microbial sulfate reduction in the extensive wetlands surrounding Pinelands streams which occurred at high rates.
AN: 1868105
1451 of 1521
TI: Selenate reduction by bacteria from a selenium-rich environment.
AU: Maiers,-D.T.; Wichlacz,-P.L.; Thompson,-D.L.; Bruhn,-D.F.
AF: Idaho Natl. Eng. Lab., Idaho Falls, ID 83415-2203, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1988. vol. 54, no. 10, pp. 2591-2593
LA: English
ER: F (Freshwater)
AB: Samples collected from Kesterson Reservoir were screened for bacterial presence and selenate reduction capability. Selenate concentrations of 100 mg/liter were not toxic to indigenous bacteria. Of the 44 samples collected, 20 possessed microbial populations capable of reducing selenate. Reduction was observed in 4% of the water samples, 92% of the sediment samples, and 100% of the soil samples. Microbial reduction of 100 mg of selenate per liter was complete within 1 week of incubation. Up to 75 mg of selenate per liter was reduced beyond selenite to an insoluble red precipitate. Data collected indicate that indigenous bacteria have a significant role in the biogeochemical cycling of selenium.
AN: 1867116
1452 of 1521
TI: (Metal and phosphorus recycling by Scirpus americanus and Spartina alterniflora in the middle Saint Lawrence Estuary (Quebec).).
OT: Recyclage des metaux et du phosphore par Scirpus americanus et Spartina alterniflora dans l'estuaire moyen du Saint-Laurent (Quebec)
AU: Deschenes,-J.; Serodes,-J.-B.
AF: Dep. Genie Civil, Univ. Laval, Que. G1K 7P4, Canada
SO: NAT.-CAN. 1986. vol. 113, no. 2, pp. 143-151
LA: French
ER: B (Brackish)
AB: This study attempting to evaluate the contribution of Scirpus americanus and Spartina alterniflora to the recycling of heavy metals and nutrients shows that the concentrations of Cu, Zn, K and P in the aboveground portion of these plants decrease during the growing season and degenerescence of the plants. The amounts of heavy metals and nutrients absorbed by these plants show a progression similar to that of the biomass, but they remain considerably less than those present in the sediments.
AN: 1865846
1453 of 1521
TI: Biogeochemical cycling of the elements in some fresh water algae from gold and uranium mining districts.
AU: Mann,-H.; Fyfe,-W.S.
AF: Geol. Dep., Univ. Western Ontario, London, Ont. N6A 5B7, Canada
SO: BIORECOVERY. 1988. vol. 1, no. 1, pp. 3-26
LA: English
ER: F (Freshwater)
AB: The contribution of fresh water algae to the retardation of heavy metal dispersion from mine tailing environments at Elliot Lake and Timmins, Canada has been examined. Algae samples from acid tailing drainage at Elliot Lake typically contained approximately equals 20 ppm U, and up to a maximum of 0.13% U by weight. Other metals which include Al, Ti, Pb, Zn, Ba, Cu, Ni, Mo, Th, Be and Zr, were also concentrated by algae. The water-sediment system from the Stanrock tailings sites revealed crystallized gamma -lepidocrocite in Euglena sp. Filamentous algae from Pearl Lake, near Timmins, also contain significant quantities of metals with concentrations 10 super(4) to 10 super(6) times that of the mine discharge water, and gold at up to 10 super(6) times the aqueous input concentration of mine process waters.
AN: 1853175
1454 of 1521
TI: Zinc, chromium, vanadium and iron in the Mediterranean Sea.
AU: Sherrell,-R.M.; Boyle,-E.A.
AF: Dep. Earth, Atmos., and Planet. Sci., Massachusetts Ins. Tech., Rm. E34-200, Cambridge, MA 02139, USA
SO: DEEP-SEA-RES. 1988. vol. 35, no. 8A, pp. 1319-1334
LA: English
ER: M (Marine)
AB: Mediterranean surface waters contain elevated levels of Zn and Cr and slightly lower levels of V compared to similar nutrient-depleted open ocean waters. A detailed mapping of surface concentrations in the Alboran Sea (immediately E of the Strait of Gibraltar) reveals that maximum total dissolvable concentrations of Zn (9.4 nmol/kg), Cr (3.9 nmol/kg), V (35 nmol/kg) and total Fe (53 nmol/kg) occur in the core of the Atlantic inflow jet. These distributions imply that a portion of Mediterranean trace metal enrichment occurs during passage of surface water through the coastal region and into the Strait, as observed previously for Cu and Cd. Cr and V levels in Mediterranean deep water are similar to surface water concentrations near deep-water formation regions, but Zn is enriched in deep water, implying some vertical transport by biological cycling. A simple steady-state box model indicates that about 30% of the Zn transport is particulate and that the Zn : nutrient ratio in sinking particulate matter is similar to that in open ocean particulates.
AN: 1852525
1455 of 1521
TI: Ammonium and phosphate uptake rates, N:P supply ratios, and evidence for N and P limitation is some oligotrophic lakes.
AU: Suttle,-C.A.; Harrison,-P.J.
AF: Dep. Bot. and Oceanogr., Univ. British Columbia, 6270 University Blvd., Vancouver, B.C. V6T 1W5, Canada
SO: LIMNOL.-OCEANOGR. 1988. vol. 33, no. 2, pp. 186-202
LA: English
ER: F (Freshwater)
AB: Natural assemblages of freshwater phytoplankton were grown in daily-dilution culture (0.50/d) at six N:P supply ratios (5:1, 10:1, 15:1, 25:1, 35:1, and 45:1; by atoms), to create a range of N- and P-limited conditions. After a minimum of 30 d in culture, subsamples were removed for determination of saturated phosphate (PO sub(4)@)u3 super(-)) and ammonium (NH sub(4)@)u+) uptake rates. A relationship (y = 0.0148e exp(0.1496x)) was found between the ratio of PO sub(4)@)u3 super(-) to NH sub(4)@)u+ uptake rates (y) and N:P supply ratio (x), indicating that this index was sensitive to the N:P supply ratio under which phytoplankton are grown. Cultures grown at the highest ratio were dominated by a chroococcoid cyanobacterium (probably Synechococcus) sp.), while those grown at the two lower ratios were dominated by the diatoms Nitzschia and Synedra and the chlorophyte Scenedesmus . Additional experiments were conducted on two oligotrophic lakes in an effort to determine if N and P co-occurred as limiting resources. Nutrient bioassay studies on water from one of these lakes indicated that N was in short supply among members of the phytoplankton community.
AN: 1849754
1456 of 1521
TI: The dissolution kinetics of diatom ooze from the Antarctic area.
AU: Kamatani,-A.; Ejiri,-N.; Treguer,-P.
AF: Lab. Marine Chem., Tokyo Univ. Fisheries, Minato-ku, Tokyo 108, Japan
SO: DEEP-SEA-RES. 1988. vol. 35, no. 7A, pp. 1195-1203
LA: English
ER: M (Marine)
AB: The dissolution kinetics of Antarctic diatom ooze was investigated in seawater at various pH's and temperatures. The slow dissolution rate of the ooze was mostly due to the presence of inhibitors postfixed on the surface layer of silica skeletons, which partly were removed by the acid treatment; inhibitors reformed gradually around the surface of acid-cleaned skeletons. The dissolution process was quite different from that of silica skeletons prepared from living diatoms, and could be described by parabolic kinetics; the concentration of dissolved silica from the diatom ooze is proportional to square root of time.
AN: 1840414
1457 of 1521
TI: Chlorinated hydrocarbons in the open Mediterranean ecosystem and implications for mass balance calculations.
AU: Burns,-K.A.; Villeneuve,-J.P.
AF: Int. Lab. Mar. Radioact., Musee Oceanogr., MC-98000, Monaco
SO: MAR.-CHEM. 1987. vol. 20, no. 4, pp. 337-359
LA: English
ER: M (Marine)
AB: Studies on the biogeochemical cycling of organic contaminants in the Mediterranean have demonstrated the importance of polychlorinated biphenyls (PCBs) as relatively stable markers of recent anthropogenic influence in ocean systems. This paper presents results of hydrocarbon analyses of deep water profiles, sediments and their associated surface flocculent layers, and zooplankton samples collected in the western basin. Analytical results are placed in the context of other distribution data for PCBs and long-term flux studies to construct a partial mass balance budget for this semi-enclosed sea. The computed coastal inventory showed that 35% remains suspended in the water column while the majority of residues are deposited in coastal sediments. However in the open sea, the deep water column may contain up to 70% of the total inventory and may be a continually increasing reservoir of stable organic contaminants.
AN: 1831438
1458 of 1521
TI: Stoichiometry of C, N, P, and Si fluxes in a temperate-climate embayment.
AU: Smith,-S.V.; Wiebe,-W.J.; Hollibaugh,-J.T.; Dollar,-S.J.; Hager,-S.W.; Cole,-B.E.; Tribble,-G.W.; Wheeler,-P.A.
AF: Hawaii Inst. Mar. Biol., Univ. Hawaii, Honolulu, HI 96822, USA
SO: J.-MAR.-RES. 1987. vol. 45, no. 2, pp. 427-460
LA: English
ER: M (Marine)
AB: Dissolved C, N, P, and Si budgets for Tomales Bay, California, have been used to solve simultaneous stoichiometric equations which describe a plausible material balance for net organic matter reactions in the bay. Dissolved Si and P were both exported hydrographically. Dissolved C and fixed N were imported hydrographically. If one assumes that C, N, P, ans Si were supplied to the bay as organic detritus and remineralized at a rate required to balance dissolved Si and P exports, one can calculate reasonable rates of denitrification and CO sub(2) gas evasion across the air-water interface. The system is thus interpreted to have been net heterotrophic at the time of the investigation.
AN: 1827611
1459 of 1521
TI: Manganese oxidation in pH and O sub(2) microenvironments produced by phytoplankton.
AU: Richardson,-L.L.; Aguilar,-C.; Nealson,-K.H.
AF: NASA Ames Res. Cent., Mail Stop 242-4, Moffett Field, CA 94035, USA
SO: LIMNOL.-OCEANOGR. 1988. vol. 33, no. 3, pp. 352-363
LA: English
ER: F (Freshwater)
AB: Pure cultures of Chlorella sp. catalyzed the oxidation of soluble Mn(II) to particulate, extracellular, manganic oxides. Manganese oxidation was dependent on photosynthetic activity: no oxidation was observed in the dark when cells were grown heterotrophically on glucose, or in the light when photosystem II was inhibited by the addition of DCMU. Manganates were not formed when media were buffered below pH 8.0, suggesting that an important driving force for manganese oxidation was the high pH resulting from photosynthesis. Field studies with minielectrodes in Oneida Lake, New York, demonstrated steep gradients of O sub(2) and pH and the presence of particulate manganic oxides associated with pelagic aggregates of the cyanobacterium Microcystis) sp.
AN: 1825702
1460 of 1521
TI: Biogeochemical studies on the transport of organic matter along the Otsuchi River watershed, Japan.
AU: Wada,-E.; Minagawa,-M.; Mizutani,-H.; Tsuji,-T.; Imaizumi,-R.; Karasawa,-K.
AF: Lab. Biogeochem. and Sociogeochem., Mitsubishi-Kasei Inst. Life Sci., Minamiooya 11, Machida, Tokyo 194, Japan
SO: ESTUAR.-COAST.-SHELF-SCI. 1987. vol. 25, no. 3, pp. 321-336
LA: English
ER: M (Marine); B (Brackish)
AB: The distributions and stable isotope ratios of biogenic nitrogen and carbon were investigated in detail along a small watershed in order to establish a biogeochemical framework for assessing the fate of organic matter. The number of suspended particles and the concentrations of delta super(15)N and delta super(13)C in the river sediments increased along the watershed, indicating a change from river to marine ecosystems. Dramatic variations of delta super(15)N and delta super(13)C were observed in the intertidal sediments, where the progress of denitrification, discharge of domestic sewage, and the accumulation and the decomposition of macroalgae and seagrasses took place. Possible factors that influence the variation of stable isotope ratios along the watershed are discussed. The relationship between the sizes of particles and isotope ratios clearly demonstrated that organo-silty-clay minerals with diameter smaller than 64 mu m were the major source of land-derived refractory organics.
AN: 1819034
1461 of 1521
TI: An experiment on the relative importance of denitrification, nitrate reduction and ammonification in coastal marine sediment.
AU: Goeyens,-L.; Vries,-R.T.P.-De; Bakker,-J.F.; Helder,-W.
AF: Netherlands Inst. Sea Res., P.O. Box 59, 1790 Den Burg, Texel, Netherlands
SO: NETH.-J.-SEA-RES. 1987. vol. 21, no. 3, pp. 171-175
LA: English
ER: M (Marine)
AB: Simultaneous determinations of super(15)N-nitrogen gas production, super(15)N-ammonia formation by nitrate reduction and ammonia production from organic nitrogen were carried out after addition of super(15)N-nitrate to anaerobically incubated sediment slurries from a location in the Dutch Wadden Sea. The rate of nitrogen gas production was 1.57 mu mol N multiplied by cm super(-3) wet sediment multiplied by d super(-1), nitrate reduction to ammonia occurred at a rate of 0.79 mu mol N multiplied by cm super(-3) multiplied by d super(-1) and ammonification at 1.17 mu mol N multiplied by cm super(-3) multiplied by d super(-1). At the end of the incubation experiment (after 30 h) 63% of the originally added super(15)N-nitrate was present as nitrogen gas, 32% ended up as ammonia and similar to 4% as particulate organic nitrogen. Ammonia production by degradation of organic nitrogen compounds was the most important process in building up the ammonia pool in the anaerobic sediment incubation.
AN: 1806393
1462 of 1521
TI: Primary and bacterial production in the Bering Sea.
OT: Pervichnaya i bakterial'naya produktsiya v Beringovom more
AU: Tsyban'-,-A.V.; Korsak,-M.N.
AF: Goskomgidromet AN S.S.S.R., Moscow, USSR
SO: BIOL.-MORYA-MAR.-BIOL.,-VLADIVOST. 1987. no. 6, pp. 15-21
LA: Russian
ER: M (Marine)
AB: The results of the 1981 summer multipurpose cruise of the R/V Akademik Shirshov are described, and tabled. Of the 4 major pilot areas surveyed, the maximum phytoplankton production (1.0-3.8 g C/m super(2)/day) and P/B coefficients were found off St. Lawrence Island. Vertical distribution of phytoplankton biomass and production varied among stations, and as a rule, the maximum of biomass was deeper than that of primary production. Bacterial production was about the same at all the stations with the maximum either within the 0-0.5 m layer or at 10-15 m. The share of bacterial production constituted from 0.5 to 150% of organic matter produced by photosynthesis. The average level of phytoplankton production in the sea for the entire vegetation period was estimated at 0.63 g C/m super(2)/day which gave the total yearly production of 2 multiplied by 10 super(8)t C sub(org).
AN: 1797465
1463 of 1521
TI: Studies on the mangrove ecosystem of Jiulong River estuary in China 2. Accumulation and biological cycle of potassium and sodium elements in Kandelia candel community.
OT: Jiulong Jiangkou hongshulin yanjiu 2. Qiuqie qunluo de Jia, Na jilei he xunhuan
AU: Lin,-Peng; Su,-Lin; Lin,-Qingyang
AF: Dep. Biol., Xiamen Univ., Xiamen, People's Rep. China
SO: ACTA-ECOL.-SIN.-SHENGTAI-XUEBAO. 1987. vol. 7, no. 2, pp. 102-110
LA: Chinese
ER: B (Brackish)
AB: The accumulation and biological cycle of potassium and sodium elements in an artificial 20-year-old Kandelia candel community in Jiulong River estuary of Fujian Province, China, were studied. The results are given.
AN: 1796161
1464 of 1521
TI: Accumulation of Fe, Mn, Cu and V in body and shells of the Black Sea mussel.
OT: Osobennosti nakopleniya zheleza, margantsa, medi, vanadiya v telakh i rakovinakh chernomorskoj midii
AU: Khrustalev,-Yu.P.; Morozov,-V.M.; Chernousov,-S.Ya.
AF: Gos. Univ., Rostov, USSR
SO: OKEANOLOGIYA-OCEANOLOGY. 1987. vol. 27, no. 6, pp. 934-938
LA: Russian
AB: The rate of assimilation and spatial distribution of the chemical elements in Mytilus galloprovincialis was found to be dependent on the mussel age and size and on the lithological type of bottom sediments. Maximum concentrations in shells and body were recorded in mussels 35-60 and 10-35 mm long, respectively, inhabiting muddy and carbonate muddy silts whereas the minimum levels were found in those occurring on sandy bottom. The metal concentrations were found to decrease seaward, which can be explained by a corresponding decrease in the levels of river-brought pollutants. It is concluded that the mollusk can be successfully used as an indicator species for pollution control.
AN: 1788854
1465 of 1521
TI: Sources and Biogeochemistry of organic matter in the Delaware Estuary.
AU: Cifuentes,-L.A.
CA: Delaware Univ., Newark (USA)
SO: DISS.-ABST.-INT.-PT.-B--SCI.-and-ENG. 1988. vol. 48, no. 8, 243 pp
NT: Diss. Ph.D.: Order No.: DA8719522.
LA: English
AB: The biogeochemistry of organic matter in Delaware Estuary sediments was studied emphasizing seasonality. Suspended particulate matter and bottom sediments were characterized by determining elemental, molecular (pyrolysis GC-MS), isotopic ( delta super(13)C and delta super(15)N), and lignin composition. Carbon and nitrogen fixed by phytoplankton was the major source of organic matter to the estuary. Seasonal differences were not found in the relative inputs of marine and terrestrial organic matter. Organic content in suspended particulate matter was greatest in the lower estuary and varied seasonally. Bottom sediments had much lower organic content. The C:N in suspended particulate matter indicated marine organic matter. Bottom sediments had higher C:N.
AN: 1782197
1466 of 1521
TI: Distribution of heavy metals in some components of coastal environment of northeastern Baltic Sea.
OT: Raspredelenie tyazhelykh metallov v nekotorykh komponentakh morskoj sredy pribrezhnoj zony Severo-Vostochnoj Baltiki
AU: Pal'-m,-T.; Sergieva,-Z.
AF: Otd. BaltNIRKh, Tallin, USSR
SO: IZV.-AN-EHST.S.S.R.-BIOL.-PROC.-ESTON.S.S.R.-ACAD.-SCI.-BIOL.. 1987. no. 1, pp. 29-36
LA: Russian
ER: M (Marine)
AB: Data are provided on the content of Zn, Cu, Pb, Cd and Fe in water, suspended matter and zooplankton. Correlation coefficients between salinity, pH, depth and suspended and dissolved forms of heavy metals were obtained. It is concluded that physico-chemical properties of suspended matter as a whole can affect significantly heavy metal accumulation in aquatic environment. Seston is supposed to accumulate heavy metals readily and influence their dynamics in water.
AN: 1782063
1467 of 1521
TI: Chlorinated hydrocarbons in individual elements of the North Atlantic ecosystem.
OT: Khlorirovannye uglevodorody v otodel'nykh ehlementakh ehkosistemy Severnoj Atlantiki
AU: Orlova,-I.G.
AF: Otd. GOIN, Odessa, USSR
SO: OKEANOLOGIYA-OCEANOLOGY-MOSC.. 1987. vol. 27, no. 6, pp. 927-933
LA: Russian
ER: M (Marine)
AB: Results are presented of the analysis of distribution of chlorinated hydrocarbons (ChH) in water, hydrobionts and bottom sediments. The levels of ChH are tabulated for 1980-1984 and the patterns of distribution as dependent on physico-geographical characteristics, species composition of zooplankton and mineral composition of bottom sediments are considered. Coefficients of accumulation of ChH in individual hydrobionts and in bottom sediments were determined. The maximum values of distribution coefficients were typical of integral plankton samples.
AN: 1781582
1468 of 1521
TI: Silica and phosphorus flux from sediments: Importance of internal recycling in Lake Michigan.
AU: Conley,-D.J.; Quigley,-M.A.; Schelske,-C.L.
AF: Dep. Fish. and Aquacult., 7922 NW 71st St., Univ. Florida, Gainesville, FL 32606, USA
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1988. vol. 45, no. 6, pp. 1030-1035
LA: English
ER: F (Freshwater)
AB: Estimated lake-wide sediment fluxes of silica and phosphorus (P) were determined and then compared with other components in the biogeochemical cycle to investigate the importance of sediment regeneration in Lake Michigan. Dissolved silica (Si) and soluble reactive phosphorus (SRP) fluxes from sediment were measured by the incubation of intact sediment cores. Differences in the supply rates and in the biogeochemical recycling rates of Si and P can lead to seasonal Si depletion in the water mass and influence the outcome of seasonal phytoplankton species succession by limiting Si availability necessary for diatom production.
AN: 1778277
1469 of 1521
TI: Accumulation and biological cycle of chloride in Bruguiera sexangula community.
OT: Hainan Dongzhai Gang hailian qunluo lu yuansu de leiji yu shengwu xunhuan
AU: Lian,-Yuwu; Lin,-Peng
AF: Dep. Biol., Xiamen Univ., Xiamen, People's Rep. China
SO: J.-XIAMEN-UNIV.-NAT.-SCI.-XIAMEN-DAXUE-XUEBAO. 1987. vol. 26, no. 3, pp. 359-365
LA: Chinese
ER: B (Brackish)
AB: The accumulation and recycling of chloride in a Bruguiera sexangula community in Dongzhai Harbour, Hainan Island (China) is discussed. The amount of chloride in the standing crop of this community was 7.05 x 10 super(3) kg/ha. Biomass of the aerial parts and underground parts were found to be 2.19 x 10 super(3) kg/ha and 4.86 x 10 super(3) kg/ha respectively. In this community, the yearly Cl super(-) return and retention were estimated to be 385 kg/ha and 266 kg/ha, hence its yearly uptake could be induced to a value of 651 kg/ha. The chloride recycling period was estimated to be 18 years.
AN: 1776513
1470 of 1521
TI: Carbon and nitrogen budgets in manured fish ponds on Israel's coastal plain.
AU: Schroeder,-G.L.
AF: Agric. Res. Organ., Fish and Aquacult. Res. Stn., Dor, Hof HaCarmel 30820, Israel
SO: AQUACULTURE. 1987. vol. 62, no. 3-4, pp. 259-279
LA: English
ER: F (Freshwater)
AB: delta C data from manure-loaded, polyculture, freshwater ponds located on Israel's coastal plain, in conjuction with information obtained from gut contents of target fish grown in these ponds, show that 50-80% of the fish yield originated from algal-based food webs harvested primarily after the algae had been processed within the detritus of the pond bottom. The remaining yield originated from manure-based food webs. In manured ponds at Dor, net primary productivity (PP) fixed an average of 5 g carbon/m super(2)/day super(1) in algal growth. Manuring added an average of 3 g organic carbon and 0.3 g inorganic nitrogen/m super(2)/day super(1). Losses of organic matter inherent in the microbial processing of the detritus prior to consumption by target animals require that, to sustain the measured fish yields, more than half of the natural food production was harvested by the target animals. The nitrogen required to sustain the measured PP in Dor ponds depended upon rapid recycling of algal nitrogen via fish and seston community metabolism, and microbial processing of algae precipitated to the detritus.
AN: 1775805
1471 of 1521
TI: Nitrate reduction in marine sediment: Pathways and interactions with iron and sulfur cycling.
AU: Soerensen,-J.
AF: Dep. Ecol. and Genet., Univ. Aarhus, Ny Munkegade, 8000 Aarhus C, Denmark
SO: GEOMICROBIOL.-J. 1987. vol. 5, no. 3-4, pp. 401-422
NT: Special issue: Anaerobic mineralization.
LA: English
ER: M (Marine)
AB: In coastal marine sediments, the interactions between NO sub(3) super(-) reduction and transformations of Fe and S compounds often occur in a strong gradient of electron activity ("redoxcline"). Denitrification activity is observed throughout the NO sub(3) super(-)-containing surface zone, although the reduction step from N sub(2)O to N sub(2) can be inhibited by H sub(2)S in the "redoxcline." Survival of denitrifiers is generally poor in NO sub(3) super(-)-free, reduced sediment; such populations are likely to employ Fe super(3+) reduction in their energy metabolism. At depth, the sediments often contain a larger capacity for "nitrate ammonification" (dissimilatory NO sub(3) super(-) reduction to NH sub(4) super(+)) than for denitrification. The "nitrate ammonification" is found commonly among fermenting bacteria, although SO sub(4) super(2) super(-) reducers may also be involved.
AN: 1774791
1472 of 1521
TI: On the content of some chemical elements in plankton of subantarctic zone of the Pacific Ocean.
OT: O soderzhanii ryada khimicheskikh ehlementov v planktone subantarkticheskoj zony Tikhogo okeana
AU: Lukashin,-V.N.; Shiganova,-T.A.
AF: Inst. Okeanol. AN SSSR, Moscow, USSR
SO: GEOKHIMIYA. 1987. no. 11, pp. 1630-1655
LA: Russian
ER: M (Marine)
AB: From data collected between 56 and 63 degree S during the 30th cruise of the R/V Dmitrij Mendeleev in December 1982-February 1983 concentrations of chemical elements in sea water and coefficients of their accumulation in plankton are presented. The maximum accumulation in plankton was accounted for by Co and Zr, whereas concentrations of Cr, Mn and Zn, Ni, Fe and Cu, Al, Ti and V, Si and Ca were lower. An inverse relationship was established between concentrations of chemicals in sea water and in plankton.
AN: 1774706
1473 of 1521
TI: (Biogeochemical role of bivalve filter feeders in the Sea of Okhotsk.).
OT: O biogeokhimicheskoj roli dvustvorchatykh mollyuskov-fil'tratorov Okhotskogo morya
AU: Kuznetsov,-A.P.; Sagajdachnyj,-A.Yu.
AF: Inst. Okeanol. AN SSSR, Moscow, USSR
SO: DOKL.-AN-S.S.S.R. 1987. vol. 297, no. 3, pp. 751-754
LA: Russian
ER: M (Marine)
AB: The paper attempts to evaluate filtration activity of the sestonophagous Bivalvia, i.e. the volume of water swept, and the amount of organic matter consumed and transformed to sediments. Data on quantitative distribution of the filtrators at depths down to 1000 m from 3 cruises of the R/V Vityaz were examined to reveal that at stations made at depths down to 100-150 m, the total filtration rate was between 1 and 101 multiplied by m super(-2) multiplied by h super(-1) whereas at offshore stations it was usually less than 1 1 multiplied by m super(-2) multiplied by h super(-1). Through a series of assumptions the authors evaluate the total yearly volume of water swept by the Okhotsk Sea mollusks on the level of 3,380 km super(3). The mollusk-produced biological production in the 0-1000 m layer is assessed as 134 th. t C per year.
AN: 1774687
1474 of 1521
TI: Biological cycling of cadmium in marine environment.
AU: Ray,-S.; McLeese,-D.W.
AF: Fish. and Environ. Sci., Fish. Res. Branch, Dep. Fish. and Oceans, Biol. Stn., St. Andrews, N.B., Canada
SO: CADMIUM-IN-THE-AQUATIC-ENVIRONMENT. Nriagu,-J.O.;Sprague,-J.B.-eds. 1987. vol. 19 pp. 199-221
ST: ADV.-ENVIRON.-SCI.-TECHNOL. 1987. vol. 19
LA: English
ER: M (Marine)
AB: The vertical distribution of cadmium is controlled by biogeochemical cycles and normally parallels the distribution of nutrients like phosphates, silicates, and nitrates in the water column. The detailed mechanism is not known, but this behavior indicates that cadmium is bioaccumulated by aquatic organisms at the surface and regenerated from the sinking biological debris in deeper waters. Marine organisms bioaccumulate cadmium not only from the aqueous media but also from bottom and suspended sediments and from food. The process may be controlled by physicochemical factors like salinity and temperature. The chemical form of cadmium in the environment is of prime importance in bioaccumulation by marine organisms. The ultimate level of cadmium in the organism is controlled not only by biotic and abiotic processes but also by metabolism of the metal by the organisms.
AN: 1772520
1475 of 1521
TI: Studies on the mangrove ecosystem of the Jiulongjiang River estuary in China. 3. Accumulation and biological cycle of calcium and magnesium in Kandelia candel community.
AU: Lin,-Peng; Chen,-Ronghua
AF: Dep. Biol., Xiamen Univ., Xiamen, Peoples Rep. China
SO: ACTA-OCEANOL.-SIN.-EN.-ED.. 1986. vol. 5, no. 3, pp. 447-455
LA: English
ER: B (Brackish)
AB: This is a paper dealing mainly with the accumulation and biological cycle of calcium and magnesium elements of the artificial 20-years old Kandelia candel community in the Jiulongjiang River estuary of Fujian Province, China. The result of measurements is that the quantities of the two elements in the standing crop are (kg/ha) 772.91 for Ca and 526.57 for Mg. In the biological cycle of the two elements, the annual uptakes are 174.86 for Ca and 89.30 for Mg (kg/ha); the amounts of Ca and Mg returned via litter fall are estimated to be (kg/ha/a) 103.28 for Ca and 40.42 for Mg; the annual retention are (kg/ha/a) 71.58 for Ca and 48.88 for Mg, respectively. The turnover periods of Ca and Mg are 8 and 13 years, respectively.
AN: 1761530
1476 of 1521
TI: Measurement of hydrolytic activity and incorporation of dissolved organic substrates by microorganisms in marine sediments.
AU: Meyer-Reil,-L.-A.
AF: Univ., Inst. Meereskd., Abt. Mar. Mikrobiol., Duesternbrooker Weg 20, D-2300 Kiel 1, FRG
SO: MAR.-ECOL.-PROG.-SER.. 1986. vol. 31, no. 2, pp. 143-149
LA: English
ER: M (Marine)
AB: A core-injection technique is described which enables the assessment of microbial activities (extracellular enzymatic cleavage of carbohydrates and proteins, incorporation of dissolved organic substrates into microbial biomass) in natural sediment cores. Microliter portions of substrates were injected at 0.5 cm intervals into natural sediment cores, which were incubated, quick frozen, dissected and analysed. For a proper application of the core-injection technique different parameters were investigated such as volume of substrate injected, significance of diffusion of substrate, concentration of substrate and incubation time, and treatment of samples to account for the non-biological "turnover" of substrates. In depth profiles of sediments from the Kiel Bight (Baltic Sea; FRG), microbial extracellular enzymatic activities were highest in the surface horizons and decreased steadily with sediment depth. Incorporation rates of dissolved organic substrates, however, revealed a more complex depth-dependent variation pattern indicating a pronounced stratification of microbial metabolism in the sediment cores.
AN: 1755861
1477 of 1521
TI: Deposition and decomposition of turtlegrass leaves.
AU: Newell,-S.Y.; Fell,-J.W.; Miller,-C.
AF: Univ. Georgia, Mar. Inst., Sapelo Island, GA 31327, USA
SO: INT.-REV.-GESAMT.-HYDROBIOL. 1986. vol. 71, no. 3, pp. 363-369
NT: Incl. 25 ref.
LA: English
ER: M (Marine)
AB: In coastal zones where prevailing winds are onshore, seagrasses are regularly deposited at the shoreline, often forming large accumulations. The authors compared the rates of output of dry matter, organic carbon, and nitrogen for turtlegrass (Thalassia testudinum ) when it decays at the shoreline or continuously submerged nearby. Output rates were either delayed (by 30 days or more) or were significantly slower for decay under submerged conditions.
AN: 1755623
1478 of 1521
TI: Decomposition in aquatic ecosystems: Summary.
AU: Day,-J.A.
AF: Dep. Zool., Univ. Cape Town, Rondebosch 7700, South Africa
CO: Limnological Society of Southern Africa Congr. on Nutrients and Decomposition: Pathways and Problems in Aquatic Ecosystems, Capetown (South Africa), Jul 1985
SO: J.-LIMNOL.-SOC.-SOUTH.-AFR. 1986. vol. 12, no. 1-2, pp. 123-126
NT: Incl. 15 ref.
LA: English
ER: M (Marine); B (Brackish); F (Freshwater)
AB: Decomposition in aquatic systems in examined, comparing processes in marine, estuarine and freshwater ecosystems. The discussion also highlights aspects that are as yet not fully understood and thus require further investigation.
AN: 1753401
1479 of 1521
TI: Decomposition in pelagic marine ecosystems.
AU: Lucas,-M.I.
AF: Mar. Biol. Res. Inst., Zool. Dep., U.C.T., Rondebosch 7700, South Africa
CO: Limnological Society of Southern Africa Congr. on Nutrients and Decomposition: Pathways and Problems in Aquatic Ecosystems, Capetown (South Africa), Jul 1985
SO: J.-LIMNOL.-SOC.-SOUTH.-AFR. 1986. vol. 12, no. 1-2, pp. 99-122
NT: Incl. bibliogr.: 160 ref.
LA: English
ER: M (Marine)
AB: During the decomposition of plant detritus, complex microbial successions develop which are dominated in the early stages by a number of distinct bacterial morphotypes. The microheterotrophic community rapidly becomes heterogenous and may include cyanobacteria, fungi, yeasts and bactivorous protozoans. Soluble low molecular weight substrates (dissolved organic matter, or DOM) are for the most part rapidly turned over and readily taken up with a high growth efficiency by bacteria although detrital particulate organic material (POM) is turned over slowly and utilized with a low growth efficiency, owing to the structural complexity of the detritus. The presence of appropriate substrate-specific strains of bacteria is important in the decomposition of both DOM and POM. Recent attempts to model decomposition processes and C and N fluxes in pelagic marine ecosystems are described. This review examines the most sensitive components and predictions of the models with particular reference to estimates of bacterial production, net growth yield and predictions of N cycling determined by super(15)N methodology.
AN: 1753379
1480 of 1521
TI: Decomposition in estuarine ecosystems.
AU: Schleyer,-M.H.
AF: Oceanogr. Res. Inst., P.O. Box 10712, Marine Parade 4056, Durban, South Africa
CO: Limnological Society of Southern Africa Congr. on Nutrients and Decomposition: Pathways and Problems in Aquatic Ecosystems, Capetown (South Africa), Jul 1985
SO: J.-LIMNOL.-SOC.-SOUTH.-AFR. 1986. vol. 12, no. 1-2, pp. 90-98
NT: Incl. bibliogr.: 95 ref.
LA: English
ER: B (Brackish)
AB: The varied sources of estuarine plant detritus and the processes and organisms involved in its decomposition are discussed. In the case of emergent and peripheral vegetation, microbial decomposition commences in the phylloplane, with fairly rapid leaching of DOM occurring soon after immersion. Residual POM, largely cellulose, is decomposed more slowly by cellulolytic micro-organisms. Phytoplankton start contributing to the DOM pool before senescence by excreting soluble substances during normal metabolism and interesting regulatory mechanisms are involved in the bacterial utilization of this material. Bacteria play a more important role than fungi in decomposition and the latter appear to be prominent only in the breakdown of mangrove litter. Predaceous microflagellates and other protists occur in association with the bacteria and feed on them, enhancing decomposition by maintaining optimal bacterial growth rates.
AN: 1753360
1481 of 1521
TI: Decomposition in freshwater ecosystems.
AU: Robarts,-R.D.
AF: Natl. Inst. Water Res., CSIR, P.O. Box 395, Pretoria 0001, South Africa
CO: Limnological Society of Southern Africa Congr. on Nutrients and Decomposition: Pathways and Problems in Aquatic Ecosystems, Capetown (South Africa), Jul 1985
SO: J.-LIMNOL.-SOC.-SOUTH.-AFR. 1986. vol. 12, no. 1-2, pp. 72-89
NT: Incl. bibliogr.: 166 ref.
LA: English
ER: F (Freshwater)
AB: This review examines the sources and composition of organic matter and the decomposition of particulate and dissolved organic matter (POM and DOM) in freshwater ecosystems. Major findings are presented. The data demonstrate that our understanding of decomposition in freshwater ecosystems is deficient. This can be mainly attributed to lack of suitable methodology. Continuing developments in the use of radioisotope technology, exoenzymatic assays and aquatic chemistry permit an optimistic outlook for a better understanding of decomposition processes in fresh waters.
AN: 1753338
1482 of 1521
TI: Urea metabolism and its significance in the nitrogen cycle in the euphotic layer of Lake Biwa. 4: Regeneration of urea and ammonia.
AU: Mitamura,-O.; Saijo,-Y.
AF: Kyoiku Univ., Lab. Environ. Sci. And Educ., Tennoji-ku, Osaka 543, Japan
SO: ARCH.-HYDROBIOL. 1986. vol. 107, no. 4, pp. 425-440
NT: Incl. 45 refs.
LA: English
ER: F (Freshwater)
AB: The regeneration rate of urea and ammonia from zooplankton excretion and microbial mineralization (microbial degradation in the case of urea) was measured in the in situ condition in the euphotic layer at two stations of Lake Biwa. The daily regeneration rate (sum of excretion and mineralization rate) for urea and ammonia was 0.88 and 5.60 mu g-at. N/1/day in a eutrophic area, and 0.14 to 0.46 and 1.10 to 1.27 mu g-at. N/1/day in a mesotrophic area. The contribution of the excretion rate in the regeneration rate ranged from 38 to 64% for urea and 56 to 76% for ammonia. Urea excretion in the total excretion rate was 3 to 30% and the urea mineralization in the total mineralization rate was 10 to 45%. The average ratio of the daily regeneration rate to the daily assimilation rate by phytoplankton was 0.82 for urea and 1.18 for ammonia. Nitrogen supply from the excretion and mineralization through these processes is in a state of dynamic balance with the nitrogen consumption by phytoplankton assimilation, and the urea and ammonia is rapidly recycling in the euphotic layer of Lake Biwa.
AN: 1751324
1483 of 1521
TI: The amino acids uptake of Oscillatoria rubescens D.C. (blue green algae).
OT: Assimilation des acids amines par Oscillatoria rubescens D.C. (Cyanophycee)
AU: Feuillade,-M.; Krupka,-H.
AF: INRA, Inst. Limnol., 75, Ave. de Corzent, 74203 Thonon-les-Bains, France
SO: ARCH.-HYDROBIOL. 1986. vol. 107, no. 4, pp. 441-463
NT: Incl. 71 ref.
LA: French
ER: F (Freshwater)
AB: This study was conducted to determine if the blue-green alga from eutrophic lakes: Oscillatoria rubescens is able to take up amino acids as nitrogen source. A mixture of super(14)C amino acids was supplied to axenic strain of O. rubescens , incorporation into algal cells were followed by liquid scintillation counting and disappearance of each acid from the medium by thin-layer autoradiochromatography. A.A. were taken up in the light as in the dark at natural low concentration and rapidly metabolized into proteins, assimilation rate increased lightly when the nitrogen cell quota decreased. Uptake occurs also in presence of ammonium salts. Assimilation rate encountered at A.A. natural low concentrations may support low growth rate (generation time: 14 days). Uptake systems of O. rubescens have high affinities for A.A. (Ks = 0.6 mu M), specially for glycine and serine, suggesting efficient competition capabilities in natural water, for O. rubescens facing bacteria in presence of dissolved amino acids. The ecological contribution of A.A. may be important as a nitrogen source in conditions where nitrogen is low.
AN: 1750127
1484 of 1521
TI: A model for the dynamics of nutrients and oxygen in the Baltic proper.
AU: Stigebrandt,-A.; Wulff,-F.
AF: Dep. Oceanogr., Univ. Gothenburg, Box 4038, S-400 40 Gothenburg, Sweden
SO: J.-MAR.-RES. 1987. vol. 45, no. 3, pp. 729-759
LA: English
ER: M (Marine)
AB: A horizontally integrated, time-dependent physical-biogeochemical model of high vertical resolution has been developed for the Baltic Sea proper. A seasonal pycnocline model computes the physical state of the mixed surface layer. Below this is an advective-diffusive model. The vertical advection is caused by a time-dependent, entraining bottom current which transports dense seawater into the system. The vertical distributions of volumes and sediment areas are accounted for by the use of the hypsographic function of the system. The chemical/biological processes controlling the distributions of nitrogen and oxygen are modelled. The model has been run for a 20 year period. When compared to the field data the computed dynamics of the mixed layer and the patterns of primary production, nutrients and oxygen appear quite realistic.
AN: 1748326
1485 of 1521
TI: The methodological approaches and some results of the study of the biogeochemical cycle of carbon in the ocean.
AU: Lyutsarev,-S.V.; Romankevich,-E.A.
AF: Inst. Oceanol., USSR Acad. Sci., 21 Krasikova St., Moscow 117218, USSR
CO: 1. Int. Symp. on Integrated Global Ocean Monitoring, Tallinn (USSR), Oct 2-10 1983
SO: INTEGRATED-GLOBAL-OCEAN-MONITORING.-PROCEEDINGS-OF-THE-1ST-INTERNATIONAL-SYMPOSIUM,-TALLINN,-USSR,-OCTOBER-2-10,-1983.-VOLUME-2. USSR-State-Comm.-for-Hydrometeorol.-and-Control-Natural-Environment-USSR 1986. pp. 357-363
LA: English
ER: M (Marine)
AB: The results are presented of investigations conducted regarding the biogeochemical carbon cycle in the ocean, describing also methods used in chemical-analytical investigation of seawater, suspensions and bottom sediments.
AN: 1736603
1486 of 1521
TI: Oceanic branch of the global biogeochemical sulfur cycle.
AU: Ivanov,-M.V.; Lein,-A.Y.
AF: Lab. Biogeochem., USSR Acad. Sci., SCOPE and UNEP Sulfur Unit, USSR
CO: 1. Int. Symp. on Integrated Global Ocean Monitoring, Tallinn (USSR), Oct 2-10 1983
SO: INTEGRATED-GLOBAL-OCEAN-MONITORING.-PROCEEDINGS-OF-THE-1ST-INTERNATIONAL-SYMPOSIUM,-TALLINN,-USSR,-OCTOBER-2-10,-1983.-VOLUME-2. USSR-State-Comm.-for-Hydrometeorol.-and-Control-Natural-Environment-USSR 1986. pp. 325-335
NT: Incl. bibliogr.: 25 ref.
LA: English
ER: M (Marine)
AB: Details are given of investigations conducted in the framework of the SCOPE project "Global Biogeochemical Sulphur Cycle". Two major groups of sulphur fluxes are dealt with: those which contribute sulphur into the ocean reservoir and those which take sulphur from the ocean reservoir to the atmosphere and lithosphere. The sulphur cycle is closely interrelated with the cycles of other elements such as carbon, oxygen and iron.
AN: 1736572
1487 of 1521
TI: Biogeochemical cycle and annual balance of oxygen, phosphorus, silicon and fixed nitrogen in the World Ocean.
AU: Ivanenkov,-V.N.; Konnova,-Y.V.; Konnov,-V.A.
AF: Inst. Oceanol., USSR Acad. Sci., 21 Krasikova St., Moscow 117218, USSR
CO: 1. Int. Symp. on Integrated Global Ocean Monitoring, Tallinn (USSR), 2-10 Oct 1983
SO: INTEGRATED-GLOBAL-OCEAN-MONITORING.-PROCEEDINGS-OF-THE-1ST-INTERNATIONAL-SYMPOSIUM,-TALLINN,-USSR,-OCTOBER-2-10,-1983.-VOLUME-3. USSR-State-Comm.-for-Hydrometeorol.-and-Control-Natural-Environment-USSR 1986. pp. 266-267
LA: English
ER: M (Marine)
AB: Nutrient cycles are ruled by the biochemical processes of photosynthesis and regeneration of organic matter. Details are given of the biogeochemical cycles and annual balances of oxygen, silicon, phosphorus and fixed nitrogen.
AN: 1736203
1488 of 1521
TI: Prospects for global ocean pollution monitoring.
AU: Bennet,-B.G.; Davies,-D.J.A.
AF: Reg. Seas Programme Act. Cent., UNEP, Nairobi, Kenya
CO: 1. Int. Symp. on Integrated Global Ocean Monitoring, Tallinn (USSR), 2-10 Oct 1983
SO: INTEGRATED-GLOBAL-OCEAN-MONITORING.-PROCEEDINGS-OF-THE-1st-INTERNATIONAL-SYMPOSIUM,-TALLINN,-USSR,-OCTOBER-2-10,-1983.-VOLUME-1. USSR-State-Comm.-for-Hydrometeorol.-and-Control-Natural-Environment-USSR 1986. pp. 201-215
NT: Incl. 19 ref.
LA: English
ER: M (Marine)
AB: Factors to be taken into account when conducting monitoring research regarding ocean pollution are examined. Regional and global ocean monitoring programmes are detailed. Requirements and feasibility of open ocean monitoring are examined, considering the air-sea interface, biogeochemical cycles, biological monitoring, background monitoring, monitoring of fisheries resources and remote sensing.
AN: 1734956
1489 of 1521
TI: Ecological investigations in the Bering Sea.
AU: Tsyban,-A.V.; Korsak,-M.N.; Volodkovich,-Yu.L.; McLaughlin,-D.
AF: Nat. Environ. Climate Monit. Lab., USSR Acad. Sci., Moscow, USSR
CO: 1. Int. Symp. on Integrated Global Ocean Monitoring, Tallinn (USSR), 2-10 Oct 1983
SO: INTEGRATED-GLOBAL-OCEAN-MONITORING.-PROCEEDINGS-OF-THE-1st-INTERNATIONAL-SYMPOSIUM,-TALLINN,-USSR,-OCTOBER-2-10,-1983.-VOLUME-1. USSR-State-Comm.-for-Hydrometeorol.-and-Control-Natural-Environment-USSR 1986. pp. 134-157
LA: English
ER: M (Marine)
AB: Long-term observations of the levels of physical, geochemical and hydrobiological processes as well as investigations of ecological and physiological properties of marine organisms in impact and background ocean regions are of importance in assessing the ecological consequences of marine pollution. Studies carried out in the Bering Sea ecosystem are detailed. Hydrological and hydrochemical processes and the biogeochemical cycle of benz(a)pyrene are described and the state of plankton communities, microbiological regime, and the benthos are examined. Elements of the Bering Sea biotic balance are also considered.
AN: 1734898
1490 of 1521
TI: The health of the oceans and the need for its monitoring.
AU: Kullenberg,-G.
AF: Inst. Phys. Oceanogr., Univ. Copenhagen, Haraldsgade 6, 2200, Copenhagen, N. Denmark
CO: 1. Int. Symp. on Integrated Global Ocean Monitoring, Tallinn (USSR), 2-10 Oct 1983
SO: INTEGRATED-GLOBAL-OCEAN-MONITORING.-PROCEEDINGS-OF-THE-1st-INTERNATIONAL-SYMPOSIUM,-TALLINN,-USSR,-OCTOBER-2-10,-1983.-VOLUME-1. USSR-State-Comm.-for-Hydrometeorol.-and-Control-Natural-Environment-USSR 1986. pp. 83-93
LA: English
ER: M (Marine)
AB: An examination is made of the health of the World's Oceans and the importance of an integrated monitoring approach. The conceptual interface-flux model is described, detailing biogeochemical cycles involved. The following contaminants are considered: sewage, PCBs and DDT, petroleum, metals and radionuclides; the problems arising when mixtures of these contaminants occur is also examined.
AN: 1734790
1491 of 1521
TI: Behaviour and ecological importance of a mud snail (Ilyanassa obsoleta ) population in a temperate macrotidal estuary.
AU: Cranford,-P.J.
AF: Dep. Fish. and Oceans, Biol. Sci. Branch, Bedford Inst. Oceanogr., Dartmouth, N.S. B2Y 4A2, Canada
SO: CAN.-J.-ZOOL.-J.-CAN.-ZOOL. 1988. vol. 66, no. 2, pp. 459-466
LA: English
ER: B (Brackish)
AB: A population of Ilyanassa obsoleta was sampled during the 8-mo. period when they are present in the intertidal zone in the Southern Bight of Minas Basin, Bay of Fundy. During November the population returned to the subtidal zone, where energy reserves are partially utilized during winter. Clustering and differential habitat selection (salt marsh or mud flat) within size classes resulted in large spatial variations in density, standing stock, and production. Production by I. obsoleta averaged 1.1 g C/m super(-2) during their study in the intertidal zone. The supply of carbon from epibenthic microalgae is insufficient to meet the requirements of this population. Detritus derived from Spartina is believed to be an important additional source of carbon. Ilyanassa obsoleta is not a major prey item of any of the better known predators in this region. Their importance to the intertidal community results from the direct (predation) and indirect (competition, disturbance, nutrient regeneration, and bioturbation) influence of their presence on sedimentary microbial processes and the resident benthic flora and fauna.
AN: 1734137
1492 of 1521
TI: Alteration of carbon cycling by beaver: Methane evasion rates from boreal forest streams and rivers.
AU: Ford,-R.J.; Naiman,-R.J.
AF: Div. Appl. Sci., Lab. Microbial Ecol., Harvard Univ., 40 Oxford St., Cambridge, MA 02138, USA
SO: CAN.-J.-ZOOL.-J.-CAN.-ZOOL. 1988. vol. 66, no. 2, pp. 529-533
LA: English
ER: F (Freshwater)
AB: In boreal forest drainage networks, beaver (Castor canadensis ) apparently influence the biogeochemical cycling of carbon by creating conditions for sediment accumulation in streams, providing anoxic conditions suitable for significant methanogenesis. To test this assumption the authors measured methane evasion rates in streams, ranging in size from first to sixth order, in the Matamek River drainage network, Quebec, Canada. Evasion rates varied between 0.04 and 4.41 g C (CH sub(4)) multiplied by m super(-2) multiplied by year super(-1). There was no correlation between stream size or water temperature and evasion rate. However, methane evasion was 33-fold greater in beaver ponds than at other sites, representing 3.6% of the measured annual carbon output.
AN: 1730857
1493 of 1521
TI: The migration process of radionuclides in artificial microhabitat.
AU: Cai,-F.-L.; Chen,-Y.; Xu,-P.-A.
AF: 3rd Inst. Oceanogr., SOA, Xiamen, People's Rep. China
SO: ACTA-OCEANOL.-SIN.-HAIYANG-XUEBAO. 1987. vol. 6, no. 3, pp. 428-433
LA: English
ER: M (Marine)
AB: According to the principle of photosynthesis with sunlight and CO sub(2) by phytoplankton supplying food for marine organisms, while the nitrogenous compounds excreted by marine animals are transferred by bacteria into the nitrate for the use of phytoplankton, an artificial microhabitat was built to investigate comprehensively the distributive relationship of super(137)Cs, super(134)Cs, super(65)Zn, super(60)Co, super(59)Fe, super(54)Mn in the parts of the microhabitat. The results show that 78 ppt. of the super(134)Cs and super(137)Cs in ion state are present in sea water, with 28 ppt. of them nearly homogeneously involved in the exchanging processes of the suspensates and organisms, and that 80 ppt. of super(59)Fe, super(54)Mn, super(65)Zn, super(60)Co were concentrated by solid substance, whose motion was mainly controlled by biological processes. The factors affecting the distribution of nuclides in each composition are discussed. As another type of research on the controlled ecological system, the present study is of reference value for studying quantitatively the migration rule of pollutants in the ocean.
AN: 1730324
1494 of 1521
TI: The behavior of super(65)Zn in artificial marine microhabitat.
AU: Chen,-Y.; Cai,-F.-L.; Qiu,-M.-H.; Xu,-P.-A.
AF: 3rd Inst. Oceanogr., SOA, Xiamen, People's Rep. China
SO: ACTA-OCEANOL.-SIN.-HAIYANG-XUEBAO. 1987. vol. 6, no. 3, pp. 444-451
LA: English
ER: M (Marine)
AB: The concentration of super(65)Zn under artificial conditions in suspended matter, sediment, algae, and excretion as well as its distribution in the organs of fish (Tilapia mossambia ), prawn (Penaeus penicillatus ), clam (Arca granosa ), clam (Cyclina sinensis ) were studied. The results show a high concentration factor of suspended matter, with a dynamic equilibrium of concentration by algae arriving after two days. The concentration factor of super(65)Zn in the intestines of fish, prawn, clam and gills of clam is very high, and their excretive rate is rapid. It was shown that the intestines and gills are critical organs of super(65)Zn concentration. The content of super(65)Zn in nucleic acid was highest, and was higher in RNA than in DNA, while that in organic acid was lowest.
AN: 1730322
1495 of 1521
TI: Nitrogen and carbon isotope ratios in seabird rookeries and their ecological implications.
AU: Mizutani,-H.; Wada,-E.
AF: Lab. Biogechem. and Sociogeochem., Mitsubishi-Kasei Inst. Life Sci., 11 Minamiooya, Machida, Tokyo 194, Japan
SO: ECOLOGY. 1988. vol. 69, no. 2, pp. 340-349
LA: English
ER: M (Marine)
AB: Various samples around gull (Larus crassirostris ) and penguin (Pygoscelis adeliae ) rookeries were examined for nitrogen and carbon isotope ratios. The results showed that input of organic nitrogen from avian breeding activity, followed by its aerobic decomposition in soil and by volatilization of the resultant ammonia, strongly dominated nitrogen flow in both rookeries. Plants, animals, and soils in the rookeries appeared dependent on the nitrogen thus provided. Major pathways of material flow in the seabird rookeries were deduced from the isotopic data. Study of stable isotopes should enable the authors to draw similar pictures for other ecosystems; it is particularly useful in places where frequent visits are impractical.
AN: 1725619
1496 of 1521
TI: Benthic respiration measured by total carbonate production.
AU: Anderson,-L.G.; Hall,-P.O.J.; Iverfeldt,-A.; Rutgers-van-der-Loeff,-M.M.; Sundby,-B.; Westerlund,-S.F.G.
AF: Dep. Anal. and Mar. Chem., Chalmers Univ. Technol. and Univ. Goeteborg, S-412 96 Goeteborg, Sweden
SO: LIMNOL.-OCEANOGR. 1986. vol. 31, no. 2, pp. 319-329
LA: English
ER: M (Marine)
AB: The suitability of total carbonate production instead of oxygen sonsumption as a measure of benthic respiration has been investigated. In situ fluxes of total carbonate, oxygen, calcium, total alkalinity, nutrients, and sulfide across the sediment-water interface were measured in diver-operated benthic flux chambers. Two chambers were run in parallel to test the influence of oxygen and pH levels on total carbonate production. In one, oxygen and pH were kept constant near ambient levels, in the other, benthic respiration was allowed to deplete oxygen and lower the pH. The flux of total carbonate, corrected for CaCO sub(3) precipitation/dissolution, was found to be a suitable measure of benthic mineralization in sediments where methane production can be neglected. The production rate of total carbonate was not seriously affected as long as the oxygen concentrations remained > 100 mu M.
AN: 1725074
1497 of 1521
TI: Sulfate reduction in coastal ecosystems.
AU: Skyring,-G.W.
AF: Baas Becking Geobiol. Lab., CSIRO, Div. Water Resour. Res., P.O. Box 1666, Canberra City, A.C.T. 2601, Australia
SO: GEOMICROBIOL.-J. 1987. vol. 5, no. 3-4, pp. 295-374
NT: Special issue: Anaerobic mineralization.
LA: English
ER: M (Marine)
AN: 1719352
1498 of 1521
TI: Trace metals in marine environment in relation to the study of their biogeochemical cycle.
AU: Seritti,-A.; Ferrara,-R.; Morelli,-E.; Barghigiani,-C.; Petrosino,-A.
AF: CNR, Ist. Biofis., Via S. Lorenzo 26, 56100 Pisa, Italy
CO: Symposium on Analytical Problems in Marine Environment, Genoa (Italy), 23-24 May 1983
SO: CHEM.-ECOL. 1986. vol. 2, no. 3, pp. 181-186
LA: English
ER: M (Marine)
AB: Concentrations of cadmium, copper, lead and zinc were measured in the waters of the Tyrrhenian Sea in relation to waste sources and the biogeochemical cycle. These concentrations were not significantly elevated in the abiotic components of the marine environment and it is concluded that they have a low residence time in these waters.
AN: 1709158
1499 of 1521
TI: (Geochemical and chemical behavior of trace elements in the Seine Estuary: Synthesis of discussions.).
OT: Comportement chimique et geochimique des elements a l'etat de traces dans l'estuaire de la Seine: Synthese des discussions
AU: Guegueniat,-P.
AF: Lab. Radioecol. Mar. CEA, BP 270, 50107 Charbourg, France
CO: Colloque National du CNRS, Caen (France), 24 Apr 1985
SO: THE-SEINE-BAY.-CNRS-NATIONAL-COLLOQUIUM,-CAEN,-24-26-APRIL-1985.. LA-BAIE-DE-SEINE.-COLLOQUE-NATIONAL-DU-CNRS,-24-26-AVRIL-1985.- Groupe-de-Recherches-Coordonnees-"Manche"-France;-CNRS,-Paris-France1986. no. 4, pp. 363-368
ST: ACTES-COLLOQ.-IFREMER.
NT: Publ. in Coop. with IFREMER; Minist. Environ.; Caen Univ. (France).
LA: French
ER: M (Marine)
AB: In the synthesis of discussions about the chemistry of the Seine Bay, the author after a note on natural references for metal concentrations, speaks about fluorides, nutrients, PCB, and metallic elements. In conclusion some suggestions about pollutants transfer towards ecosystems link, are enumerated.
AN: 1701530
1500 of 1521
TI: Biological availability of sediment-bound trace metals.
AU: Luoma,-S.N.
AF: U.S. Geol. Surv., Mail Stop 465, 345 Middlefield Rd., Menlo Park, CA 94025, USA
CO: Colloque National du CNRS, Caen (France), 24 Apr 1985
SO: THE-SEINE-BAY.-CNRS-NATIONAL-COLLOQUIUM,-CAEN,-24-26-APRIL-1985.. LA-BAIE-DE-SEINE.-COLLOQUE-NATIONAL-DU-CNRS,-24-26-AVRIL-1985.- Groupe-de-Recherches-Coordonnees-"Manche"-France;-CNRS,-Paris-France1986. no. 4, pp. 347-362
ST: ACTES-COLLOQ.-IFREMER.
NT: Publ. in Coop. with IFREMER; Minist. Environ.; Caen Univ. (France).
LA: English
ER: M (Marine)
AB: It has been established that direct uptake of (at least some) trace metals from sediments contributes to metal concentrations in benthic organisms. Important controls on metal uptake from sediment are the concentration of the exposure, the partitioning of the metals among components of the sediment, and the redox potential of the sediment. Important problems in ecology, physiology, geochemistry and biogeochemistry remain unresolved, however, and a concentrated interdisciplinary research effort will be necessary before a complete understanding of the fate and impact of sediment-bound metals will be possible.
AN: 1701514
1501 of 1521
TI: (Mineral and organic soluble forms of zinc, iron and copper: Distribution in the Seine Estuary.).
OT: Etude de la distribution des formes solubles minerales et organiques du fer, du zinc et du cuivre dans l'estuaire de la Seine
AU: Gandon,-R.; Guegueniat,-P.; Fischer,-J.C.; Wartel,-M.
AF: Lab. Radioecol. Mar., CEA-IPSN-DERS/SERE, BP 270, 50107 Cherbourg, France
CO: Colloque National du CNRS, Caen (France), 24 Apr 1985
SO: THE-SEINE-BAY.-CNRS-NATIONAL-COLLOQUIUM,-CAEN,-24-26-APRIL-1985.. LA-BAIE-DE-SEINE.-COLLOQUE-NATIONAL-DU-CNRS,-24-26-AVRIL-1985.- Groupe-de-Recherches-Coordonnees-"Manche"-France;-CNRS,-Paris-France1986. no. 4, pp. 327-336
ST: ACTES-COLLOQ.-IFREMER.
NT: Publ. in coop. with IFREMER; Minist. Environ.; Caen Univ. (France).
LA: French
ER: M (Marine)
AB: One characteristic of the Seine Estuary system is the process of sediment resuspension by the specific hydrodynamics of this environment. It's the main factor of trace metals transport. Autotrophic activities also have an effect on the estuary, by pH variation. The behavior of soluble and organic copper, iron, have been studied in relation to salinity in and out of the estuary. The results are compared with those of other estuaries.
AN: 1701473
1502 of 1521
TI: (Evolution of metal complexation (Ca, Mg, Cd, Pb, Cu) in the Seine Estuary.).
OT: Evolution de la complexation des metaux (Ca, Mg, Cd, Pb et Cu) dans l'estuaire de la Seine
AU: Fischer,-J.C.; Wartel,-M.
AF: Lab. Chim. Anal. Mar., Univ. Lille 1, Batim. C8, 59655 Villeneuve d'Ascq Cedex, France
CO: Colloque National du CNRS, Caen (France), 24 Apr 1985
SO: THE-SEINE-BAY.-CNRS-NATIONAL-COLLOQUIUM,-CAEN,-24-26-APRIL-1985.. LA-BAIE-DE-SEINE.-COLLOQUE-NATIONAL-DU-CNRS,-24-26-AVRIL-1985.- Groupe-de-Recherches-Coordonnees-"Manche"-France;-CNRS,-Paris-France1986. no. 4, pp. 321-326
ST: ACTES-COLLOQ.-IFREMER.
LA: French
ER: M (Marine)
AB: Interaction between metallic ions and dissolved organic matter can take major part in the biogeochemical cycle of metals in the aquatic environment. The authors point out copper behavior by the study of complexing capacity of surface and bottom waters. A systematic analysis of major elements in natural waters has allowed for a proposal of geographical distribution of metals.
AN: 1701460
1503 of 1521
TI: (The complexing properties of waters in Seine Estuary.).
OT: Pouvoir complexant des eaux de l'estuaire de la Seine
AU: Fischer,-J.C.; Wartel,-M.; Guegueniat,-P.; Gandon,-R.
AF: Lab. Chim. Anal. Mar., Univ. Lille 1, Batim. C8, 59655 Villeneuve d'Ascq Cedex, France
CO: Colloque National du CNRS, Caen (France), 24 Apr 1985
SO: THE-SEINE-BAY.-CNRS-NATIONAL-COLLOQUIUM,-CAEN,-24-26-APRIL-1985.. LA-BAIE-DE-SEINE.-COLLOQUE-NATIONAL-DU-CNRS,-24-26-AVRIL-1985.- Groupe-de-Recherches-Coordonnees-"Manche"-France;-CNRS,-Paris-France1986. no. 4, pp. 315-320
ST: ACTES-COLLOQ.-IFREMER.
NT: Publ. in coop. with IFREMER; Minist. Environ; Caen Univ. (France).
LA: French
ER: M (Marine)
AB: Copper has been studied, by the authors, owing to its ability to complex with various organic ligands of natural waters. Metals extraction and liberation can be explained, in part, by this complexing capacity.
AN: 1701443
1504 of 1521
TI: Variations of upwelling and associated nutrient nitrogen dynamics off the north-west coast of South Island, New Zealand.
AU: Viner,-A.B.; Wilkinson,-V.H.
AF: Taupo Res. Lab., Dep. Sci. and Ind. Res., P.O. Box 415, Taupo, New Zealand
SO: N.Z.-J.-MAR.-FRESHWAT.-RES. 1987. vol. 21, no. 2, pp. 253-266
LA: English
ER: M (Marine)
AB: The surface distribution and metabolic uptake of nitrate and ammonium were investigated as they related to the movements of water in the upwelling zone off the north-west coast of South Island, New Zealand. The movement of water and resulting dispersion from the upwelling focus were shown to differ greatly from day to day; this could confound simple correlations between nutrient nitrate and phytoplankton. A suitable model to investigate metabolic processes due to influx of fertile upwelled water which could avoid this problem can be based upon assays of NO sub(3) and NH sub(4) uptake by the plankton.
AN: 1690192
1505 of 1521
TI: Biogeochemical cycling of selenium in the San Joaquin Valley, California, USA.
AU: Presser,-T.S.; Ohlendorf,-H.M.
AF: U.S. Geol. Surv., 345 Middlefield Rd. (MS-435), Menlo Park, CA 94025, USA
SO: ENVIRON.-MANAGE. 1987. vol. 11, no. 6, pp. 805-821
LA: English
ER: F (Freshwater)
AB: Subsurface agricultural drainage waters from western San Joaquin Valley, California, were found to contain elevated concentrations of the element selenium in the form of selenate. In 1987, these drainage waters began to replace previous input to Kesterson Reservoir, a pond system within Kesterson National Wildlife Refuge; this substitution was completed by 1982. In the 1983 nesting season, unusual rates of deformity and death in embryos and hatchlings of wild aquatic birds occurred at the refuge and were attributed to selenium toxicosis. Features necessary for contamination to have taken place included geologic setting, climate, soil type, availability of imported irrigation water, type of irrigation, and the unique chemical properties of selenium.
AN: 1689100
1506 of 1521
TI: Differential thermal and thermogravimetric analysis of sediment-forming materials from Lake Ontario.
AU: Zimmermann,-G.M.; Lean,-D.R.S.; Charlton,-M.N.
AF: Wunderhornstr. 8, 8000 Munich 90, FRG
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1987. vol. 44, no. 12, pp. 2216-2224
LA: English
ER: F (Freshwater)
AB: Differential thermal analysis (DTA) and thermal gravimetric analysis (TGA) are techniques for studying physical and chemical changes of materials as they are heated at a specific rate in a defined atmosphere (usually air, but oxygen or nitrogen can be used). Reactions such as oxidation, pyrolysis, evaporation, or other shifts in energy state cause the temperature of the sample to differ from the inert reference material. The record of temperature differences provides the DTA profile. With TGA, the weight of the sample is recorded as the temperature is increased. DTA and TGA of seston, sediments, and sediment trap material from Lake Ontario were generally similar to each other but were strikingly different from those of the green alga Chlorella pyrenoidosa . Coinciding with the principal weight loss of carbohydrate material, the main exothermic reaction for all lake samples began at 200-250 degree C and peaked at 345-355 degree C.
AN: 1686894
1507 of 1521
TI: (Tunis Lake eutrophication: The bacterial and planktonic processes.).
OT: Phenomenes bacteriens et planctoniques dans l'eutrophisation du lac de Tunis
AU: Belkhir,-M.; Aubert,-M.; Aubert,-J.; Mathonnet,-S.
AF: Inst. Natl. Sci. Tech. Oceanogr. Peche, Stn. Oceanogr., Salommboe, Tunisia
CO: 8. Colloque International d'Oceanographie Medicale, Nice (France), 9 Oct 1985
SO: PROCEEDINGS-OF-THE-8th-INTERNATIONAL-SYMPOSIUM-ON-MEDICAL-OCEANOGRAPHY,-9-12-OCTOBER-1985,-NICE-FRANCE.. ACTES-DU-8eme-COLLOQUE-INTERNATIONAL-D'-OCEANOGRAPHIE-MEDICALE,-9-12-OCTOBRE-1985,-NICE-FRANCE.- Drach,-P.;Nissenbaum,-A.;Aubert,-M.;Aubert,-J.-eds.1987. no. 85-86 pp. 39-45
ST: REV.-INT.-OCEANOGR.-MED. no. 85-86
LA: French
ER: M (Marine)
AB: This study uses the observations of colored water cycles, evolution and the variations of chemical elements. The authors try to show ecological and metabolic information towards interspecific relationships. They draw up a plan of the evolution of the eutrophication processes.
AN: 1686873
1508 of 1521
TI: Report of the FAO/UNEP/WHO/IOC/IAEA Meeting on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena, Italy, 27-31 August 1984.
OT: Rapport de la Reunion FAO/PNUE/OMS/AIEA sur le Cycle Biogeochimique du Mercure en Mediterranee, Sienne, Italie, 27-31 aout 1984
CA: FAO, Rome (Italy)
CO: FAO/UNEP/WHO/IOC/IAEA Meet. on the Biogeochemical Cycle of Mercury in the Mediterranean, Siena (Italy), 27 Aug 1984
SO: FAO-RAPP.-PECHES. 1986. no. 325, 17 pp
NT: 29 ref. ISBN 92-5-202242-2.
RN: FAO FIRI/R325 (Fr) (FIRIR325Fr)
LA: French
ER: M (Marine)
AB: Processes regarding the distribution, behavior and fate of mercury in the marine environment are examined with respect to chemical, physical and biological characteristics and the ocean-atmosphere dynamics. Levels of mercury in the Mediterranean are discussed in particular.
AN: 1685880
1509 of 1521
TI: Overview of studies on the nutrient status of Lake Ontario.
AU: Lean,-D.R.S.
AF: Natl. Water Res. Inst., Canada Cent. Inland Waters, P.O. Box 5050, Burlington, Ont. L7 4A6, Canada
SO: CAN.-J.-FISH.-AQUAT.-SCI. 1987. vol. 44, no. 12, pp. 2042-2046
LA: English
ER: F (Freshwater)
AB: Balancing human demands on the environment with the overall welfare of the biosphere is one of the greatest challenges facing society today. In lakes, the limits of use and abuse are set by biogeochemical processes. This issue integrates measurements of lake physics and nutrient availability with the response of the microbial community in Lake Ontario. Such information is vital to the understanding of factors affecting the base of the food chain and relates to the phosphorus abatement programs of the past 15 yr.
AN: 1685565
1510 of 1521
TI: Potential heterotrophy of deep-sea sediments. Effects of pressure (test compound = super(14)C glucose).
OT: Heterotrophie potentielle des sediments marins profonds. Effect de la pression (traceur = super(14)C glucose)
AU: Cahet,-G.; Bianchi,-A.; Ralijaona,-C.
AF: Lab. Arago, 66650 Banyuls-sur-Mer, France
CO: Bacteriologie Marine, Marseille (France), 17-19 May 1982
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-SYMPOSIUM-No.-331-ON-MARINE-BACTERIOLOGY,-CNRS,-MARSEILLE,-17-19-MAY-1982.. ACTES-DU-COLLOQUE-INTERNATIONAL-No.-331-SUR-LA-BACTERIOLOGIE-MARINE-ORGANISE-DANS-LE-CADRE-DES-COLLOQUES-INTERNATIONAUX-DU-CENTRE-NATIONAL-DE-LA-RECHERCHE-SCIENTIFIQUE-A-MARSEILLE-DU-17-AU-19-MAI-1982.- Bianchi,-A.-ed.1984. pp. 225-229
ST: COLLOQ.-INT.-CNRS. no. 331
LA: French
ER: M (Marine)
AB: Deep sediment samples from several geographical areas, incubated with super(14)C glucose, showed strong microbial activity. Such activity, demonstrated by samples studied aboard the ship, were only considered as measurement of potential heterotrophy. Most of the time super(14)CO sub(2) was the product of activity, but, in some cases, super(14)C glucose was transformed in other compounds found in diverse fractions extracted by the geochemical analysis.
AN: 1659717
1511 of 1521
TI: Degradation of mangrove leaf litter in the St. Lucia Estuary as influenced by season and exposure.
AU: Steinke,-T.D.; Ward,-C.J.
AF: Dep. Bot., Univ. Durban-Westville, Private Bag X54001, Durban 4000, South Africa
SO: S.-AFR.-J.-BOT.-S.-AFR.-TYDSKR.-PLANTKD. 1987. vol. 53, no. 5, pp. 323-328
LA: English
ER: B (Brackish)
AB: Rates of degradation of leaves of Avicennia marina (Forssk.) Vierh. and Bruguiera gymnorrhiza (L.) Lam. were investigated in St Lucia Estuary in the warm and cool seasons at three positions on the shore, viz, where leaves were constantly submerged, where they were exposed only at low spring tides and where they were inundated only at high spring tides. Degradation occurred more rapidly in A. marina than in B. gymnorrhiza and leaves constantly submerged decomposed at a faster rate than those exposed for most of the time. Decomposition rates were consistantly lower in the cool season. The concentration of nitrogen in all leaves increased over the decomposition period, although there was decreased in total nitrogen content with rapid decomposition. This work has emphasized the importance of mangrove leaf litter as a source of, and substrate for, nutrient release.
AN: 1659325
1512 of 1521
TI: Bacterial degradation of organic matter in seawater: Use of biogeochemical markers.
OT: Degradation bacterienne de la matiere organique dans les eaux de mer: Approche par les marqueurs biogeochimiques
AU: Saliot,-A.; Andrie,-C.; Jullien,-D.; Lorre,-A.; Marty,-J.C.; Scribe,-P.
AF: Lab. Phys. Chim. Mar., Univ. Pierre et Marie Curie, ERA CNRS Tour 24, 4 Place Jussieu, 75230 Paris Cedex 05, France
CO: Bacteriologie Marine, Marseille (France), 17-19 May 1982
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-SYMPOSIUM-No.-331-ON-MARINE-BACTERIOLOGY,-CNRS,-MARSEILLE,-17-19-MAY-1982.. ACTES-DU-COLLOQUE-INTERNATIONAL-No.-331-SUR-LA-BACTERIOLOGIE-MARINE-ORGANISE-DANS-LE-CADRE-DES-COLLOQUES-INTERNATIONAUX-DU-CENTRE-NATIONAL-DE-LA-RECHERCHE-SCIENTIFIQUE-A-MARSEILLE-DU-17-AU-19-MAI-1982.- Bianchi,-A.-ed.1984. pp. 51-56
ST: COLLOQ.-INT.-CNRS. no. 331
LA: French
ER: M (Marine)
AB: Microorganisms play a key role in the cycling of organic matter in the marine environment, particularly at specific sites such as the air-water, water-sediment and water-particulates interfaces. The total budget of organic matter can be achieved by analyses of sources, evolution and bacterial activity markers. The evolution of concepts concerning the utilization of bacterial markers will be discussed, regarding the development of structure elucidation of fatty acids in different series: saturated, unsaturated, branched and hydroxylated. Budgets of organic matter and bacterial markers (fatty acids, hydrocarbons) are presented.
AN: 1658968
1513 of 1521
TI: Heterotrophic microbial activity in marine Antarctic sediments.
OT: Activite microbienne heterotrophe dans les sediments marins antarctiques
AU: Tanner,-A.C.; Herbert,-R.A.
AF: British Antarct. Surv., Madingley Rd., Cambridge, UK
CO: Bacteriologie Marine, Marseille (France), 17-19 May 1982
SO: PROCEEDINGS-OF-THE-INTERNATIONAL-SYMPOSIUM-No.-331-ON-MARINE-BACTERIOLOGY,-CNRS,-MARSEILLE,-17-19-MAY-1982.. ACTES-DU-COLLOQUE-INTERNATIONAL-No.-331-SUR-LA-BACTERIOLOGIE-MARINE-ORGANISE-DANS-LE-CADRE-DES-COLLOQUES-INTERNATIONAUX-DU-CENTRE-NATIONAL-DE-LA-RECHERCHE-SCIENTIFIQUE-A-MARSEILLE-DU-17-AU-19-MAI-1982.- Bianchi,-A.-ed.1984. pp. 29-32
ST: COLLOQ.-INT.-CNRS. no. 331
LA: English
ER: M (Marine)
AB: During December and January, rates of primary production in the near-shore coastal waters of Signy Island are high. Following the collapse of the phytoplankton bloom there is little evidence that moribund phytoplankton reaches the sediment since CHN analyses of benthic sediments show very low total nitrogen (0.03%) and carbon (0.42%) with little variation on a seasonal basis. These data indicate that heterotrophic microorganisms present in the water column and surface sediments play a significant role in the mineralisation of moribund plankton. The main objective of this study was to determine the heterotrophic potential of the microbial flora in maritime Antarctic waters and surface sediments. Two approaches have been used to estimate heterotrophic activity, the first involving the determination of individual microbial populations on a seasonable basis and the second, the uptake of super(14)C-labelled glucose and acetate by naturally occurring bacterial populations.
AN: 1658909
1514 of 1521
TI: Role of sea floor organisms in oxygen consumption in the deep North Pacific Ocean.
AU: Jahnke,-R.A.; Jackson,-G.A.
AF: Skidaway Inst. Oceanogr., Savannah, GA 31416, USA
SO: NATURE. 1987. vol. 329, no. 6140, pp. 621-623
LA: English
ER: M (Marine)
AB: Here the authors present estimates of sedimentary oxygen consumption made using benthic flux and pore-water measurements extrapolated throughout the North Pacific basin as a function of water depth. Below 3 km, sea-floor respiration is a large and perhaps dominant contributor to deep-ocean metabolism. This benthic activity appears to be highly concentrated in regions adjacent to continental margins exhibiting coastal upwelling. More extensive benthic respiration measurements are needed to verify this, especially in the northern and western Pacific Ocean.
AN: 1658841
1515 of 1521
TI: (Evaluation of heterotrophic activity and study of parameters related to the organic carbon cycle of limnetic environments.).
OT: Stime di attivita eterotrofa e studio dei parametri inerenti al ciclo del carbonio organico negli ambienti limnici
AU: Bertoni,-R.; Callieri-Bertoni,-C.; Contesini,-M.; Torelli,-R.
SO: REPORT-ON-THE-SCIENTIFIC-ACTIVITY-OF-THE-INSTITUTE-DURING-THE-YEAR-1983.. RELAZIONE-SULL'-ATTIVITA-SCIENTIFICA-DELL'-INSTITUTO-NELL'-ANNO-1983.- Istituto-Italiano-di-Idrobiologia,-Verbania-Pallanza-Italy1984. no. 1 pp. 58-72
ST: DOC.-IST.-ITAL.-IDROBIOL. no. 1
NT: Incl. 19 ref.
LA: Italian
ER: F (Freshwater)
AB: Problems related to the methods involved in the estimation of heterotrophic activity are examined and discussed with respect to research conducted on parameters characterizing organic carbon cycles in Lake Mergozzo.
AN: 1658359
1516 of 1521
TI: (Preliminary studies on the distribution of metallic elements in Lake Como.).
OT: Indagine preliminare sulla distribuzione di elementi metallici nel Lago di Como
AU: Baudo,-R.; Galanti,-G.; Guilizzoni,-P.; Varini,-P.G.
SO: REPORT-ON-THE-SCIENTIFIC-ACTIVITY-OF-THE-INSTITUTE-DURING-THE-YEAR-1983.. RELAZIONE-SULL'-ATTIVITA-SCIENTIFICA-DELL'-INSTITUTO-NELL'-ANNO-1983.- Istituto-Italiano-di-Idrobiologia,-Verbania-Pallanza-Italy1984. no. 1 pp. 20-24
ST: DOC.-IST.-ITAL.-IDROBIOL. no. 1
NT: Incl. 13 ref.
LA: Italian
ER: F (Freshwater)
AB: The findings of sampling studies regarding the levels of metals in Lake Como are discussed. The aquatic macrophyte flora and their role in the recycling of metals and sedimentation are examined.
AN: 1658236
1517 of 1521
TI: Ammonium production in sediments inhibited with molybdate: Implications for the sources of ammonium in anoxic marine sediments.
AU: Jacobson,-M.E.; Mackin,-J.E.; Capone,-D.G.
AF: Mar. Sci. Res. Cent., State Univ. New York, Stony Brook, NY 11794, USA
SO: APPL.-ENVIRON.-MICROBIOL. 1987. vol. 53, no. 10, pp. 2435-2439
LA: English
ER: M (Marine)
AB: Ammonium production in the presence of specific inhibitors of sulfate reduction and methanogenesis was investigated in six marine sediments which differed in bulk properties and organic matter input. In all cases, little effect of the inhibitors on ammonium production was observed, although sulfate reduction was suppressed by molybdate. This gives evidence that the processes of fermentation and hydrolysis are of primary importance in ammonium generation at the sites studied. Although sulfate reduction rates may appear to ge coupled to ammonium production rates, sulfate reduction does not necessarily contribute directly to generation of ammonium in marine environments.
AN: 1649400
1518 of 1521
TI: Studies of nitrogen cycling with experimental benthic chamber incubations.
AU: Prieto,-M.C.; Corredor,-J.E.
AF: Dep. Mar. Sci., Univ. Puerto Rico, Mayaguez 00708, Puerto Rico
CO: 18. Meet. of the Association of Island Marine Laboratories of the Caribbean, St. James (Trinidad), 13 Aug 1984
SO: PROC.-ASSOC.-ISL.-MAR.-LAB.-CARIBB. 1984. vol. 18, p. 3
NT: Rec'd 1987. Summary only.
LA: English
ER: M (Marine)
AB: Inorganic nitrogenous compounds and the impact of cultural eutrophication were studied for a seagrass/mangrove ecosystem in southwestern Puerto Rico utilizing 1 station in a mangrove channel (CS) with houses discharging untreated wastes; and 2 reference stations (RS) with Thalassia testudinum and sandy sediments. Benthic chamber incubations were conducted to measure exchange of nitrogenous compounds between the sediments and the overlying water. An RS upcurrent showed a slight release of NO sub(3) from the sediments. NH sub(4) concentration also increased. Both were effectively taken up by the T. testudinum) and plankton in the water column. NO sub(3) release from sediments indicates that sediments are oxygenated in the upper layer, possibly due to release of oxygen by T. testudinum). The CS had sediments with high organic content, decaying Microcoleus lyngbyaceous and no T. testudinum . Release of NH sub(4) from the sediments and effective uptake by the plankton in the water column were documented. NO sub(3) decrease in the chamber coupled with an increase of NH sub(4) suggest that NO sub(3) is being reduced to NH sub(4) in the sediments. The down current RS showed a release of NH sub(4) from the sediments and a gradient formation in the water column due to low mixing rates.
AN: 1645387
1519 of 1521
TI: (Organic matter biogeochemistry in estuarine environment: Behaviour, fluxes, properties. An application to the Gironde estuary (France).).
OT: Biogeochimie de la matiere organique en milieu estuarien: Comportement, bilan, proprietes. Cas de la Gironde
AU: Etcheber,-H.
AF: Univ. Bordeaux 1, Inst. Geol. Bassin Aquitaine, 33405 Talence, France
SO: MEM.-INST.-GEOL.-BASS.-AQUITAINE. TALENCE-FRANCE-UNIV.-BORDEAUX-1,-INST.-GEOL.-BASSIN-D'-AQUITAINE 1986. no. 19, 379 pp
LA: French
ER: B (Brackish)
AB: This thesis investigates material and energy fluxes carried by rivers to the ocean. Using an original multidisciplinary approach the author studies the organic fraction (particulate organic matter, POM) of suspended matter in a macrotidal estuary--the Gironde. In the upstream region POM comes from basin slopes during winter and is essentially autochtonous from Apr. to Sep. Particles poor in OM in the center of the estuary are in the high turbidity zone and contain essentially detrital OM. Particles rich in OM are found at the mouth of the estuary where concentration of marine OM is very high, particularly during summer. Hydrology and climate are primordial factors acting on the distribution and behaviour of POM in estuaries. In the Gironde estuary, POM is an essential scavenger of trace elements (mainly Zn, Cu). Degradation processes of POM induce drastic mobilization of bound heavy metals.
AN: 1644413
1520 of 1521
TI: Redfield ratios, primary production, and organic carbon burial in the Baltic Sea.
AU: Shaffer,-G.
AF: Oceanogr. Inst., Univ. Gothenburg, Box 4038, 400 40 Gothenburg, Sweden
SO: DEEP-SEA-RES. 1987. vol. 34, no. 5-6, pp. 769-784
NT: Special issue: Biological effects on the chemistry of the sea.
LA: English
ER: M (Marine)
AB: The biogeochemical cycling of oxygen, phosphorus and carbon in the Baltic Sea is investigated using a natural coordinate conservation method. The mean Redfield ratio of oxygen consumption to phosphate production due to organic decomposition is found to be 159 plus or minus 6 in the Baltic proper deep water. Utilizing the C:N ratio for particulate matter in the deep water, a "best" set of Redfield ratios is found to be 159:130:14.4:1 for -O sub(2):C:N:P. Present net community production in the Baltic proper appears to be similar to 50 plus or minus 7 g C m super(-2) y super(-1) as calculated from oxygen consumption rates and transport rates of "new" PO super(3)@)d4 super(-) into the euphotic zone. Total primary production is estimated to be similar to 175 g C m super(-2) y super(-1), consistent with super(14)C primary production in the Baltic proper. Also, organic carbon may be presently buried at a rate of similar to 10 g C m super(-2) y super(-1).
AN: 1634352
1521 of 1521
TI: The enrichment of lagoons with organic carbon by supratidal sabkhas: Example of the Bahiret el Biban paralic complex (Tunisia).
OT: Le role des sebkhas supratidales dans l'enrichissement des lagunes en carbone organique: L'exemple du complexe paralique de la Bahiret el Biban (Tunisie)
AU: Medhioub,-K.; Chesterikoff,-A.; Perthuisot,-J.-P.
AF: Ec. Natl. Ing. Sfax (GREDOPAR), Route de la Soukra, Sfax, Tunisia
SO: J.-RECH.-OCEANOGR. 1985. vol. 10, no. 1, pp. 29-31
LA: French
ER: M (Marine)
AB: Bahiret el Biban is one of the largest Mediterranean lagoons. As a peculiar feature, it possesses supratidal sabkhas in the sedimentary piles of which waters coming from the lagoon undergo an evaporitic evolution prior to returning to the lagoon water body. These processes induce in the latter a relative enrichment with Mg and impoverisment with sulfate. The following studies of the paralic complex have shown the existence of water masses bearing high organic carbon contents. This organic carbon is, at least partly, generated within the sabkhas interstitial brines by the bacterial consumption of cyanobacterial mats which grow on their intertidal margins and are buried under recent sediments in their supratidal areas.
AN: 1627650