Geochemical ocean sections study (GEOCECS). Chemistry of ocean solutions

The GEOSECS project is a multi-institutional investigation of the geochemistry and mixing dynamics of the oceans. The objective of this study is to utilize the oceans' chemical and radionuclide constituents to characterize the biogeochemical and physicodynamic processes occurring in the oceans. Results are reported from the characterization of a large group of trace elements in the oceans, and the measurement and utilization of cosmic-ray and fallout radionuclides as tracers of aerosol deposition and ocean mixing processes. The radionuclide studies have now been completed and the program has been directed towards measurement of the distributions of trace metals of geochemical and environmental interest in the oceans utilizing the valuable inventory of well-documented GEOSECS samples. The analyses of sea water from open ocean GEOSECS tracks are being supplemented by trace metal measurements of seawater samples collected on cruises extending from the coastlines of the U.S. to open ocean areas. These data will help define the natural and anthropogenic processes which create concentration gradients between the coastal and open ocean waters. The air-to-sea transfer of airborne trace metals to the coastal marine environment, the chemical species after dissolution, and subsequent chemical reactions which will affect bioavailability were also studied. The validity of 7Be as a tracer for air-sea transfer of trace metals is being investigated presently. The distribution chemical/physical forms of plutonium in the Pacific Northwest coastal waters and sediments is also being studied to predict the future consequences of plutonium inputs to the coastal ecosystem