Dr. Sherrell and his laboratory group studies the biogeochemistry of trace metals in the modern ocean and uses this understanding to develop new geochemical paleo-records of past ocean conditions. They are helping to increase the general knowledge of the distribution and dynamics of trace metals and isotopes in the ocean through the international GEOTRACES program, and recently completed GEOTRACES cruises in the tropical South Pacific and in the Arctic Ocean. They are very interested in metals that act as micro-nutrients for phytoplankton, and have active research programs exploring the mechanisms of natural Fe fertilization of ocean productivity in two shelf regions off west Antarctica. In addition, they are developing new geochemical paleo-proxies in tropical and deep-sea corals and are using these to develop histories of nutrients and the carbonate system of the past ocean.

Part of this work involves long-term culturing studies with slow-growing deep corals to determine coral skeleton chemistry as a function of tightly controlled seawater chemistry; this work is being carried out in Barcelona. They are also pursuing high-resolution paleo-climate results by determining minor elements and isotopes in an 83,000 year old stalagmite from a cave on the SW Pacific island of Niue, with the goal of reconstructing rainfall at this site and unraveling its relationship to polar and global climate variations. Periodically, they make measurements of iridium and other platinum group metals in sediment sections that cross major extinction events in earth’s history, as part of an effort to determine the role of major extraterrestrial impacts. They are very active in developing analytical techniques using plasma source mass spectrometry, which are applied to all of these research endeavors.