Background Information

The World Ocean plays a dynamic role in the Earth's climate: it captures heat from the sun, transports it, and releases it thousands of miles away. These oceanic-solar-atmospheric interactions affect winds, rainfall patterns, and temperatures on a global scale. The oceans also play a major role in global carbon cycle processes. Carbon in the oceans is unevenly distributed because of complex circulation patterns and biogeochemical cycles, neither of which is completely understood. In addition to circulation patterns, biological processes (i.e., photosynthesis and respiration) play a crucial role in the carbon cycle. The oceans are estimated to hold 38,000 gigatons of carbon, which is 50 times more carbon than that in the atmosphere and 20 times more carbon than that held by plants, animals, and the soil (Williams 1990). Thus, if only 2% of the carbon stored in the oceans is released, the level of atmospheric carbon dioxide (CO₂) would double (Williams 1990). Furthermore, every year more than 15 times as much CO₂ is exchanged across the sea surface than the amount produced by the burning of fossil fuels, deforestation, and other human activities (Williams 1990).

Several large experiments were conducted in the past, and others are currently under way, attempting to better understand the oceans and their role in climate and the global carbon cycle. One of the earliest large-scale oceanographic projects was the Geochemical Ocean Section Study (GEOSECS). The goal of GEOSECS was to study geochemical properties of the oceans with respect to large-scale circulation problems. The project, which covered the Atlantic (1972-73), Pacific (1973-74), and Indian (1977-78) oceans, officially started in 1971 and was noted for its use of equipment and techniques that were at the forefront of modern technology and knowledge. The Transient Tracers in the Ocean (TTO) project (1982) was designed to measure the distribution of CO₂ and hydrographic properties in the North Atlantic Ocean. The World Ocean Circulation Experiment (WOCE) started in 1990 and is currently under way. WOCE is the first research program of sufficient scope to mount a true global study of the ocean. WOCE brings together the expertise of scientists and technicians from many nations in an oceanographic experiment that is larger than any ever attempted. Another multinational program currently under way is the Joint Global Ocean Flux Study (JGOFS). The purpose of JGOFS is to investigate the processes controlling marine biogeochemical cycles, specifically carbon and nutrient cycles.

During the lifetime of the WOCE project, from 1990 to 1997, approximately 23,000 stations will be sampled in oceans around the world. This document provides and describes data collected during a 45-day expedition in the South Atlantic Ocean, Northern Weddell Sea, and Drake Passage aboard the German research vessel Meteor. The cruise, referred to as cruise number 11, leg 5 (11/5), was conducted during the austral summer. It started at Ushuaia, Argentina, on January 23, 1990, and ended at Capetown, South Africa, on March 8, 1990. Seventy-eight stations were occupied along the WOCE sections A-21 and A-12 (Fig. 1).

The CO₂ investigation during the R/V Meteor Cruise 11/5 was supported by a grant from the U.S. Department of Energy (DOE) No. DE-FGO2-90ER60943.