Brief Cruise Information and Summary

Table 2 illustrates general cruise information.

Table 2. R/V Meteor Cruise 28/1 Information

^aParticipating Institutions:
Biologische Anstalt Helgoland (BAH);
Brookhaven National Laboratory (BNL);
Diretoria Hidrografia e Navegacao, Brazil (DHN);
German Weather Service / Sea Weather Office (DWD/SWA);
Institute of Applied Physics of the University of Kiel (IAPK);
Institute für Meereskunde der Universitet Kiel (IfMK);
Institute of Oceanographic Sciences, Wormley, UK (IOS);
Universitt Bremen, Fachbereich Tracer Oceanographie (UBT); and
Institute for Physics and Atomsphere, University of Mainz (UMZ).

Originally, the R/V Meteor Cruise 28/1 was scheduled to terminate at Pointe Noir in the Republic of the Congo. However, unknown to the responsible German authorities, the U.S. State Department had issued a travel warning urging Americans to defer travel to the Congo! K. M. Johnson of BNL forwarded this warning to Dr. Walter Zenk of IfMK, who confirmed the warning with the German government. After a furious exchange of faxes, the Meteor team was informed that the final cruise destination (i.e., termination point) was changed to Walvis Bay, Namibia, which had just been transferred from the Republic of South Africa to Namibia a few days earlier. Johnson arrived in Recife on March 27, 1994, where he was joined by BNL CO₂ group members Craig Neill and Kevin Wills. The CO₂ group boarded the R/V Meteor on March 28 and immediately began to set the instruments up. The two SOMMA-coulometry systems along with the discrete fCO₂ system were located in the Meteor's universal laboratory adjacent to the geo- laboratory

The R/V Meteor departed Recife, Brazil, on March 29 at approximately 2 p.m. local time. Work began after crossing the twelfth nautical mile (12-nm) zone of Brazil when the underway recording systems (the towed Geomagnetic Electro Kinetograph, the acoustic Doppler current profiler, and the navigational data system) were switched on. Test stations (Stations 165 through 168) were taken the first two days of the cruise to set up and test the CO₂ instruments. WOCE Section A8 began with station 169 outside the 12-nm zone of Brazil on April 1, at 10° 03' S and 35° 46' W on the 200-m depth contour. Subsequent stations at intervals of from 5 to 20 nm were taken until Station 181 at the nominal latitude of 11° 20' S and 34° 00' W. After Station 181, the station interval was increased to 30 nm until station 185 (32° W) and increased to 38 nm thereafter (beyond the 200-nm economic zone of Brazil). Prior to the 200-nm zone, sampling usually included plankton tows, but their frequency decreased in the open ocean waters to every 70 to 90 nm. Station spacing was narrowed to 30 nm as the ship approached the Mid-Atlantic Ridge (Stations 200-210) and then narrowed to 24 nm over the ridge (until Station 222). The African continental break at 8° E was reached at Station 260, whereby 28 nm spacing was sampled until 10° E was reached at Station 264 at the 200-nm economic zone of Angola. The CTD section work continued until Station 274 at the 50 nm zone. While waiting for further clearance, the northern part of a box around the eastern tail of A8 was surveyed using the CTD/ADCP system down to 1000 m. When clearance came, two days later, the R/V Meteor resumed the A8 section at 11° 20' S and 13° 05' E on Station 287 and completed the section on the 200-m depth contour with Station 290 on May 7. The ship arrived at Walvis Bay on May 10. Apart from some showers on April 9, a small swell (2 to 3 m) between April 10 and 19, and fog off of the Angola coast due to cold upwelling waters, the weather remained mostly sunny with summer temperatures and relatively calm seas. Of special note was the very excellent Easter repast prepared for R/V Meteor team by the galley staff which featured pheasant, smoked salmon, venison, and many other delicacies.

Two single-operator multi-parameter metabolic analyzers (SOMMA) were used on this cruise. One was supplied by BNL (serial No. 004) and the other by the IfMK (serial No. 014). In addition, a gas chromatographic (GC)-based system for measuring discrete fCO₂ was deployed. The CO₂ samples were drawn in conjunction with tracer samples from 51 of 108 WOCE CTD stations (47% coverage) occupied during the cruise (Fig. 2). As on previous cruises, not all stations could be sampled for TCO₂ and fCO₂ because of the time required for analysis. However, the goal of approximately 50% coverage was attained. The standard WOCE parameters (temperature, oxygen, nutrients, and salinity) were analyzed on all samples. The tracer samples included chloroflurocarbons (CFCs), helium (He), tritium (H3), and radiocarbon (¹⁴C).

Analytical problems were confined mostly to damage during transit. A pipette along with a jacketed sample bath were broken, but replacements were available on board ship for these items. Some of the refrigerated baths used for thermostating the instruments (particularly the fCO₂ shaking bath) labored under the limitations of the 50-cps power aboard the R/V Meteor. One bath caught fire and was destroyed. The gas calibration hardware functioned throughout the cruise on both SOMMA systems (004 and 014). Downtime for both systems was limited to the time required to change the cells and a few incidents requiring minor adjustments to hardware or software. The CO₂ measurement team deployed on this cruise probably represents one of the most experienced analytical groups ever assembled for a single cruise. A brief look at the references will confirm the collective contributions of the measurement group to the accurate determination of dissolved CO₂ in seawater before and during the WOCE CO₂ Survey.