Low dissolved iron concentrations limit the growth of phytoplankton over large areas of the surface ocean. Atmospheric deposition of mineral aerosols ('dust') provides a primary input of iron to open-ocean surface waters, thus variations in this atmospheric input flux may exert a significant control on atmospheric carbon dioxide via the ocean's biological pump. In this context, a key variable is the proportion of aerosol iron that dissolves in the surface ocean, which soil dust is thought to be quite small (around 1%). In this talk, I will use data from Bermuda, Greenland, and Antarctica to argue that anthropogenic combustion emissions constitute a significant source of highly-soluble aerosol iron, such that human activities are perturbing the availability of this essential micronutrient, and possibly other bioactive trace elements, in the surface ocean.

Peter Sedwick received B.S. (Chemsitry) and Ph.D. (Oceanography) degrees from the University of Hawaii at Manoa. He was a Research Scientist at the University of Tasmania's Antarctic Cooperative Research Centre from 1993-2001 and an Associate Research Scientist at the Bermuda Institute of Ocean Sciences from 2001-2008. Dr. Sedwick joined Old Dominion University as an Associate Professor in the Department of Ocean, Earth and Atmospheric Sciences in 2008. His research focuses on the marine biogeochemistry of trace metals and their role in regulating primary production in the sea.

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