2014_metadata.xml eng; USA utf8 dataset Nancy Rabalais Louisiana Universities Marine Consortium Distinguished Research Professor 1 985-851-2801 985-851-2874 Chauvin LA 70344 USA nrabalais@lumcon.edu principalInvestigator 2017-02-17T20:01:10+00:00 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) Physical (Hydrography), chemical (CTD), and biological (Water Quality) processes of the Texas-Louisiana continental shelf, 2014 Louisiana Hypoxia Surveys 2014 2017-02-17 publication Two sets of CTD data were taken during the 2014 Shelfwide Hypoxia cruise off the Louisiana continental shelf. Hydrographic data were obtained with the LUMCON SeaBird 911+ CTD system and a YSI 6820. Nutrient, pigment, suspended sediment, surface salinity, Secchi depth, Winkler results, and station information data were also acquired. The physical, biological and chemical data collected are part of a long-term coastal Louisiana dataset. The goal is to understand physical and biological processes that contribute to the causes of hypoxia and use the data to support environmental models for use by resource managers. The size of the hypoxic area is part of the baseline data considered by the Mississippi River/Gulf of Mexico Nutrient/Hypoxia Task Force. completed Nancy Rabalais Louisiana Universities Marine Consortium Distinguished Research Professor 1 985-851-2801 985-851-2874 Chauvin LA 70344 USA nrabalais@lumcon.edu principalInvestigator hypoxia Biogeochemical Cycles Nutrient Cycling Oxygen Demand Primary Production Eutrophication Water Quality Chlorophyll Conductivity Light Transmission Nitrogen Oxygen pH Suspended Solids Water Temperature Coastal Processes Marine Environmental Monitoring Ammonium nitrate Phosphate Pigments silicate fronts secchi depth Ocean Temperature Salinity/Density theme Gulf of Mexico North Atlantic Ocean United States of America North America Northern Hemisphere Sea Surface place eng;USA oceans biota environment 28.4833 -94.0672 29.7239 -94.0672 29.7239 -89.4104 28.4833 -89.4104 28.4833 -94.0672 ground condition 2014-02-25 2014-10-09 2014_YSI6820: Station ID (Integer), Date (MM/DD/YY), Station (Character field), Time (Zulu, HH:mm:ss), Depth (Meters), Dissolved Oxygen (mgO2/L), Temperature (Degrees centigrade), Specific conductance (mS/cm), Salinity (psu), Percent Oxygen Saturation (%), Chlorophyll a (µg/L). 2014_Nutrients: Station ID (Integer), Date (MM/DD/YY), Station (Character field), Depth (Meters), Vial Number (Integer), Ammonium concentration (µM/L), Nitrite + Nitrate concentration (µM/L), Phosphate concentration (µM/L), Silicate concentration (µM/L). 2014_Pigments: Station ID (Integer), Date (MM/DD/YY), Station (Character field), Depth (Meters), Mean Chlorophyll a (µg/L), Mean Phaeopigments (µg/L), Total pigments (µg/L), Mean F (Mean Fo/Fa ratio). 2014_Salinity: Station ID (Integer), Date (MM/DD/YY), Station (Character field), Depth (Meters), Salinity (psu). 2014_Winkler: Station ID (Integer), Date (MM/DD/YY), Station (Character field), Depth (Meters), Winkler Dissolved Oxygen (mgO2/L). 2014_Seabird: Station ID (Integer), Date (MM/DD/YY), Station (Character field), Seabird scan count (Integer), Depth (Meters), Altimeter (Meters), In water PAR (µEinsteins m-2 sec-1), Light transmission (Percent), In vivo fluorescence (Chl µg/L), Temperature (Degrees centigrade), Conductivity (S/m), Salinity (psu), Density (sigma-t, kg m-3), Dissolved Oxygen Concentration (mgO2/L), Percent Oxygen Saturation (%). 2014_SPM: Station ID (Integer), Date (MM/DD/YY), Station (Character field), Depth (Meters), Inorganic suspended particulate material (mg/L), Organic suspended particulate material (mg/L), Total suspended sediments (mg/L). 2014_StationList: Station ID (Integer), Date (MM/DD/YY), Station (Character field), Latitude of sampling station (Decimal degrees), Longitude of sampling station (Decimal degrees), Arrival Time at Station (Zulu, HH:mm), Time of SeaBird CTD cast (Zulu, HH:mm), Time of YSI CTD cast (Zulu, HH:mm), Fathometer (Meters), Secchi disk depth (Meters), Altimeter (Meters), Midas Salinity (psu), Comments (Character Field).|Field YSI Methodology_Description: The YSI CTD was attached by chain to a lead weight. The weight was lowered to the bottom by hydrowire. With the weight on the bottom, the sonde was positioned approximately 0.5 meters above the bottom. When the oxygen sensor stabilized, a data record of all the sensor values was stored electronically. During the Shelfwide cruise, the sonde was raised in approximately 0.5-meter increments, after D.O. sensor stabilization on the bottom; data records were stored. After storing data for the few meters closest to the bottom, the sonde was raised to two to three meters from the surface and a data record was saved. The sonde was raised and records stored in approximately 0.5-meter increments until finally a record was stored with the sonde submerged but as close as possible to the surface. Field Nutrient Methodology_Description: Care was taken that the collector's hands were clean and avoided touching the sample water. Gloves were worn when two replicate sample vials and caps were triple rinsed with sample before vial filling and closing. Samples were not filtered. The sample vials were frozen for later analysis in the laboratory. Field Pigment Methodology_Description: Water for chlorophyll analysis (10 - 100 ml) was filtered on board ship through GF/F (0.7 micron) filters, which were then fixed in 5 ml of DMSO/90% acetone (40/60) solution, allowed to extract for at least two hours in the dark, then measured pre- and post-acidification on a Turner Model 10 AU fluorometer. Field Seabird CTD Methodology_Description: The SeaBird CTD number of scans to average in the deck unit was set to one. At the beginning of each hydrocast the entire CTD/Rosette package was soaked while submerged 0.5m to 1.0m below the surface until pump flow and oxygen values observed via the Sea-Bird deck unit indicated the system was operating correctly. Sensor packages are located below the Niskin bottle rosette sampler. In order to minimize the effect of delays in oxygen sensor response time caused by temperature, sensor condition and plumbing configuration, the CTD package was lowered as close to dead slow as possible. The sensor packages were located below the Niskin bottles and rosette. At stations where the watch chief deemed the structure of the oxygen profile contained features useful in post-processing the oxygen data (AlignCTD), the CTD package was raised at the same speed it was lowered. At all other stations, the upcast was rapid in order to save time. Field SPM Methodology_Description: Water (approximately 50 to 1500 ml) collected for suspended sediment samples was filtered on board ship through (pre-combusted, pre-weighed) GF/F filters and rinsed with distilled water. The filters were placed in Petri dishes and frozen for later analysis. Field Salinity Methodology_Description: Water was collected in an acid-washed, triple-rinsed 500ml Nalgene jar from a twice-rinsed bucket of surface water. The jar lid was secured tightly to minimize evaporation. Salinity samples were only collected at stations along the C and F transects during the cruise. Field Winkler Methodology_Description: Water was collected from Niskin Bottle samples using a 300ml glass BOD bottle. Care was taken so that air bubbles were not introduced into the water sample and titration reagents were added immediately to fix the oxygen. Stations and depths were selected as water samples for Winkler analysis based on homogeneity the oxygen profile around that depth, and the need for a distribution of oxygen values across the observed oxygen range. Field Station Locations Methodology_Description: During the July shelfwide cruise stations were occupied along 14 generally North-South transects across the Louisiana and Texas coastal shelves. Station depths ranged from 2.40 to 49.10 meters. The objective was to delimit and describe the area of midsummer bottom dissolved oxygen less than 2 (mg/L). Northern end stations of transects were chosen based on the survey vessel's minimum depth limits for each longitude. The northern extent of hypoxia was not reached on transects A’, A, B, C, D', E, I and E. Hypoxic oxygen levels were found in transects A’, A, B, C, D', D, E, F, H, I, J, and K. Field water samples Methodology_Description: Water for chlorophyll, nutrient, salinity, and suspended sediment analyses was collected from the surface by twice-rinsed bucket at all stations. Bottom water samples for chlorophyll, nutrient, and salinity analyses were collected in a 5-l bottom tripping Niskin deployed on the YSI hydrowire at all stations. Bottom water samples for suspended sediment analyses were only collected at C6C and CSI-9 stations. Mid water samples were collected at C6C and CSI-9 stations, for analysis of chlorophyll, nutrient, and suspended sediment in 5-l Niskin bottles on the SeaBird CTD/rosette system or a messenger triggered 5-l Niskin on the YSI hydrowire. Depth values of "0" indicate a bucket sample collected from the surface of the water. Generally, deepest depths of water samples were from the bottom-tripping Niskin and correspond to the deepest depth recorded from the YSI. Midwater samples were collected using Niskin bottles on the SeaBird rosette. Depths for midwater samples were taken from corresponding Seabird data, adjusting for the SeaBird pressure sensor being located approximately 0.75 meters below the mid-point of the 5-L Niskin. Lab Nutrient Methodology_Description: Ammonium samples were analyzed according to Lachat Instrument's QuikChem method 31-107-06-1-B. Phosphates are determined by Lachat Instrument's QuikChem Method 31-115-01-1-H. Silicates were measured using Lachat Instrument's Method 31-114-27-1-C. TKN was determined using Lachat Instrument's QuikChem Method 10-107-06-2-H. Nitrates and Nitrites were determined using Lachat Instrument's Method 31-107-04-1-C. Lab SPM Methodology_Description: Suspended sediment filters were dried overnight at 60°C and weighed. The filters were then combusted at 400°C for 12 hours and weighed. The weights of the total suspended, organic and inorganic materials were derived. Lab SeaBird CTD Methodology_Description: Sea-Bird CTD data were acquired using Seasoft and processed using SBE Data Processing-Win32 software. All scans were processed without averaging or interpolation with a bin size of one scan. In order to compensate for the delay in oxygen sensor response time and improve the alignment between oxygen sensor values and temperature and conductivity sensor values, the Seasoft module ALIGNCTD was used. See Field SeaBird CTD for selection process of which stations were used for alignment. After alignment, the DERIVE function was used to calculate Depth (m), Salinity (psu), Density sigma-t (kg/m3), Oxygen concentration (mg/L), and Oxygen percent saturation (%). Final data were exported as ascii files. A MATLAB program was used to select a water column profile made up of scans from the downcast of discrete 1-meter (or 0.1-m) measurements. The MATLAB program selected scans as follows: 1) Data from Seabird warm up period sitting on the surface were removed; 2) Upcast data were removed; 3) Data scans were selected at 1.0 meter increments through the water column; 3) When DO values changed significantly (> 1.0 mgO2/L) within 1-meter, scans at 0.1-m intervals were selected within that meter; 4) Minimum oxygen and maximum depth scans were selected.|SeaBird CTD, Optical Spectrometer, YSI – 6820 handheld multi-parameter instrument, 5-L Niskin bottle, conductivity sensor, fluorometer (Turner digital 1-AU), oxygen titrator (Mettler Toldeo DL28), pressure sensors, secchi disk, SeaBird CTD unit with 12 5-l sampling rosette, Sea-Bird Electronics SBE-9+ Underwater Units with Digiquartz Pressure Sensor, 4127 and 6885 meter depth, Sea-Bird Electronics SBE-11 Deck Unit. Temperature Sensors (SBE 3-01/F) 6,800 meter depth, Conductivity Sensors, % transmission sensors, SBE 43 dissolved oxygen sensors (2), Chelsea Instruments Aquatraka III Chlorophyll a in vivo fluorescence sensor. |See coordinates below. Extending from Mississippi River delta to upper Texas coast. An average of 30 minutes per station and one hour between stations. Working 24 h per d. Lowering rate of the CTD, 1 m/s. YSI 6820, depth not changed until stabilized; not continuous; but hand recorded.|Examination for values +/- 2 SD of mean. Visual inspection for values inconsistent with replicates, and others in a continuous string. Visual inspection for values outside of range of instrument. Comparison with hand-written values. Evaluation of suspected values with station log notes. 2014_YSI6820: The YSI 6820 Conductivity, pH, Oxygen, and Chlorophyll sensors were serviced and calibrated before deployment and maintained in accordance with YSI (http://www.ysi.com/) recommended procedure. The Sonde and Logger are returned to the factory at least annually for inspection and service. Small adjustments based on correlations with Portasal and YSI values were made to YSI salinity data for the July Shelfwide cruise. Shipboard Winkler titrations during the cruises were used to develop regressions against the YSI data in case it was necessary to correct the oxygen data. YSI oxygen data were corrected for the July Shelfwide cruise using an equation based on the results of the regression. pH data are not included for 2014 data, as the pH sensor was not functioning properly. Elevated bottom YSI Chlorophyll data are due to high levels of Phaeopigments in the hypoxic bottom water in most cases, or potentially sediment kicked up from the weight hitting the bottom. 2014_Nutrients: Nutrient analyses were conducted using a QuikChem 8000 FIA+ (http://www.lachatinstruments.com). Charlie Milan performed the analyses under the supervision of R. E. Turner, LSU. 2014_Pigments: The Turner Designs model 10 AU fluorometer was calibrated (3/21/2011 & 7/17/2014) for chlorophyll a against a chemical supply house chlorophyll a standard measured on a spectrophotometer. Each time the fluorometer was moved, it was tested with a Turner 10-AU solid standard. During cruises, the fluorometer was blanked and calibrated daily in accordance with Turner Designs recommended procedures. Pigment measurements were supervised by Nancy Rabalais and quality controlled by Nancy Rabalais. 2014_Seabird: Sea-Bird SBE 13-01 dissolved oxygen sensors, the Paroscientific Digiquartz(r) pressure sensor, the SBE 3-01/F temperature sensors, SBE 5-01 pumps, and the SBE 4-01/0 Conductivity sensors were factory tested and calibrated at Sea-Bird (http://www.seabird.com/) recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff in accordance with Sea-Bird procedures. The Chelsea Instruments Aquatraka III Chlorophyll a sensor was factory tested and calibrated at recommended intervals and maintained and serviced by RV Pelican Electronic Technical support staff in accordance with Chelsea Instruments procedures. Note: WET Labs acquired SEA Tech June 1, 1998, (http://www.wetlabs.com/). The Wet Labs C Star 10 cm path transmissometer was maintained by RV Pelican Electronic Technical support staff in accordance with Wet Labs recommendations. Small adjustments based on correlations with Portasal and Seabird values were made to Seabird salinity data for the July Shelfwide cruise. At the beginning of the July Shelfwide cruise, oxygen sensors were calibrated using the procedures described in SeaBird APPLICATION NOTE NO. 13-1, Rev. D. The Winkler Titration oxygen value was determined chemically from replicate samples processed using a Mettler DL21 Titrator (http://www.mt.com/). Shipboard Winkler titrations were performed during the Shelfwide cruise to develop regressions against the SeaBird data. Seabird oxygen data were corrected for the cruise data using an equation based on the results of the regression. Winkler titrations were conducted under the supervision of Nancy Rabalais. SeaBird data post processing was done by Leslie Smith and Wendy Morrison and quality controlled by Nancy Rabalais. N.B. Near bottom high altimeter values (>6.0 m) were deleted throughout the dataset, because probes were likely within 1 meter of the bottom. N.B. Seabird cast F2A-2 was conducted to collect bottle samples at 8.0m depth. As such, the cast did not go all the way down to the seafloor. N.B. Surface irradiance data for the Shelfwide cruise were removed; values were exceptionally low, it is likely the sensor was obstructed. As such, CPAR % data could not be calculated, and only in water PAR data have been included. 2014_SPM: Suspended sediment concentrations were supervised and quality controlled by Nancy Rabalais. 2014_Salinity: Salinity samples were analyzed in the lab by Guildline Instruments Portasal, using Guildline methods (http://www.guildline.ca/). Salinity analyses were conducted by Wendy Morrison under the supervision of Nancy Rabalais. 2014_Winkler: Winkler samples were analyzed on board the R/V Pelican with a Mettler Toledo DL28 Titrator using dissolved oxygen determination methods outlined in A Practical Handbook of Seawater Analysis by Strickland and Parsons, 1977. Winkler analyses were conducted by Wendy Morrison under the supervision of Nancy Rabalais. 2014_StationList: SeaBird times and locations of operations were logged from RV Pelican's Multiple Instrument Data Acquisition System (MIDAS), which was maintained by the ship's electronic staff. Navigational data were acquired from a Starlink (http://www.starlinkdgps.com/) differential GPS or a Trimble (http://www.trimble.com/) GPS with a Micronet Receiver Station with sub 5-meter accuracy. Station depths were logged from the ship's Odom Echotrac II (http://www.odomhydrographic.com/) fathometer. Additionally, YSI6820 casts were made on a few dates from a small boat. See Horizontal_Positional_Accuracy_Report for details. Secchi disk depths were measured by hand using standard protocol. N. Rabalais performed an additional procedure in quality-control/quality-assurance by evaluating relationships between the data in 2014_YSI6820, 2014_Nutrients, 2014_Pigments, 2014_Seabird, 2014_SPM, 2014_Salinity, 2014_Winkler, and 2014_StationList. Horizontal_Positional_Accuracy: Cruise station positions were logged from RV Pelican's differential GPS at the beginning of sampling operations. GPS manufacturer's accuracy claim is 1-5 meters 95% of the time. Wind, currents and tidal forces may have moved the ship from the beginning position. In addition to the July Shelfwide cruise, YSI casts were made at stations C6C, and CSI-9 on a few dates from a small boat using a Garmin 12XL Personal Navigator. The manufacturer describes the unit as being accurate within 15 meters 95% of the time.|Hypoxia surveys in the Northern Gulf of Mexico have been conducted annually since 1985. National Oceanographic and Atmospheric Administration, National Centers for Environmental Information N/A N/A Washington DC N/A USA NODC.DataOfficer@noaa.gov http://www.nodc.noaa.gov/ distributor Excel spreadsheets 0.8 This ISO metadata record was created using the 'Check and Save to File' (with form validation) function of the GRIIDC ISO 19115-2 Metadata Editor on 2017-02-15T20:42:22+00:00 This ISO metadata record was created using the 'Save to File' (no form validation) function of the GRIIDC ISO 19115-2 Metadata Editor on 2017-02-17T20:45:48+00:00