Project: Trace-metal isotopes in Atlantic seawater and particles from Geotraces transects A03 and A10

Trace metals significantly affect marine biogeochemistry and can be important tools of discovery, leading to information on nutrient supply and demineralization, ocean circulation, and earth?s climate history. Due to their importance, the international GEOTRACES effort was designed to measure the distribution of metals in the oceans. However, metal concentration distributions are only a part of the larger picture. To provide a more complete dataset, researchers from the University of South Carolina propose to measure trace metal isotopes (Fe, Cd, Cu, and Zn) and plan to apply these data to distinguish between the latest competing hypotheses of factors influencing metal biogeochemcial cycling. Many processes can fractionate the isotopes of elements and therefore differences in the isotope signal can be instructive of biogeochemical cycling of these elements. The goal of the project is to address the origin and amount of biologically available iron, its modification during internal cycling, its transfer between pools, and the factors that influence its bioavailability. In addition, Zn and Cd isotope analyses will yield information on modern and ancient oceans, which could help predict how oceans change in future climates. the isotopes of cu will also be examined. Results will inform the ocean science community, and elucidate how trace-metals and other nutrients affect production and are impacted by climate change.