Human Impact on the Atmospheric Input of Iron to the Surface Ocean
Peter Sedwick, Old Dominion University
9 Nov 2012
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 for soil dust is thought to be quite small (around 1%). In this talk, I will use field data 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 micronutrient, and possibly other bioactive trace elements, in the surface ocean.
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