This project will allow the principle investigator to participate in an internationally-sponsored oceanic baseline survey of dissolved trace elements in the Atlantic Ocean. Primarily, this investigator will focus on the geochemistry of the element gallium, though certain other elements such as aluminum, manganese, copper, nickel, and cadmium will be determined. There are several objectives of this research. First, the research will answer certain questions about the behavior of gallium in seawater. These questions include the cause of the high gallium/aluminum ratios observed in seawater (compared with continental rocks) and to extent of a mid-depth maximum in gallium/aluminum ratios observed in the North Pacific. A second objective of the research is to use gallium as a less-reactive analogue of aluminum in the deep waters of the Atlantic. There has been some interesting previous research using aluminum as a water tracer in the deep Atlantic. By comparing the behavior of gallium with that of aluminum, a key assumption involved in the use of aluminum as a tracer (conservative behavior in the deep Atlantic) can be tested. A final objective relates to the international focus of the research. The cruises are sponsored by the Intergovernmental Oceanographic Commission (sponsored by UNESCO). The purpose is to put together baseline information on trace element concentrations and to allow an international group of investigators to intercalibrate their results. This intercalibration is important because of unresolved problems relating to the absolute concentrations of certain trace elements in seawater.
