SSRL Science
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External supplies of iron to the world's oceans come largely from fine
sediments and dusts that can be transported from continents by ocean currents,
or as aerosols deposited on the ocean surface. Aerosols are most notably
derived from arid and seasonally-arid areas, where winds can entrain
significant particulates and transport them long distances. Glaciers also
produce considerable sediments that can form aerosols; Alaska contains numerous
glaciers that efficiently grind rock that delivers both aerosols and suspended
sediments to the Gulf of Alaska (Figure 1). Anthropogenic aerosols from fossil
fuel emissions and other sources are can be important in some areas.
This work has three important implications to our understanding of iron cycling
in the ocean. This work provides a chemical basis for the substantial
differences in iron solubility for different iron particles. Second, it shows
that glacial processes can affect the ocean in complex and previously
unexplored ways. As glaciers recede in response to global climate change, the
increased dust delivery to the oceans may serve as a feedback mechanism to
influence atmospheric carbon dioxide levels and thereby moderate climate
change. At very least, changes in climate will affect the distribution and
source of dust sources to the world's oceans, thereby affecting marine
productivity and the global carbon cycle. Third, this work highlights the
potentially important role of anthropogenic aerosols in regulating dissolved
iron levels, and thus photosynthesis, in the oceans. In the North Pacific
Ocean, the increased fossil fuel use in China and elsewhere in Asia may
increase the aerosol concentration of oil fly ash. Since oil fly ash is highly
soluble, this increase could profoundly affect primary production.
Primary Citation
Andrew W. Schroth, John Crusius, Edward R. Sholkovitz and Benjamin C. Bostick,
"Iron solubility driven by speciation in dust sources to the ocean", Nature
Geosci., 2, 337-340 (2009).
Further Readings
For more on the role of iron in the oceans, see the following: (a) Martin, J.
H., Gordon, R. M. & Fitzwater, S. E. Limnol. Oceanogr. 36,
1793-1802 (1991).; (b) Moore, J. K., Doney, S. C., Glover, D. M. & Fung, I. Y.
Deep-Sea Res. I 49, 463-507 (2002). (c) Jickells, T. D. et al.
Science 308,
67-71 (2005). (d) Lam, P. J. & Bishop, J. K. B. Geophys. Res. Lett.
35, L07608
(2008). (e) Journet, E., Desboeufs, K. V., Caquineau, S. & Colin, J. L.
Geophys. Res. Lett. 35, L07805 (2008).
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SSRL is supported by the Department of Energy, Office of Basic Energy Sciences. The SSRL Structural Molecular Biology Program is supported by the Department of Energy, Office of Biological and Environmental Research, and by the National Institutes of Health, National Center for Research Resources, Biomedical Technology Program, and the National Institute of General Medical Sciences. |
Last Updated: | 23 June 2009 |
Content Owner: | B. Bostick, Dartmouth College |
Page Editor: | L. Dunn |