John, Seth G. and Adkins, Jess (2012) The vertical distribution of iron stable isotopes in the North Atlantic near Bermuda. Global Biogeochemical Cycles, 26 . Art. No. GB2034. ISSN 0886-6236 http://resolver.caltech.edu/CaltechAUTHORS:20120711-132003222
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Seawater dissolved iron isotope ratios (δ^(56)Fe) have been measured in the North Atlantic near Bermuda. In a full-depth profile, seawater dissolved δ^(56)Fe is isotopically heavy compared to crustal values throughout the water column (δ^(56)Fe_(IRMM-014) = +0.30‰ to +0.71‰). Iron isotope ratios are relatively homogenous in the upper water column (between +0.30‰ to +0.45‰ above 1500 m), and δ^(56)Fe increases below this to a maximum of +0.71‰ at 2500 m, decreasing again to +0.35‰ at 4200 m. The δ^(56)Fe profile is very different from the iron concentration profile; in the upper water column [Fe] is variable while δ^(56)Fe is relatively constant, and in the deeper water column δ^(56)Fe varies while [Fe] remains relatively constant. The δ^(56)Fe profile is also not well correlated with other hydrographic tracers in the North Atlantic such as temperature, salinity, or the concentrations of oxygen, phosphate, silica, and CFC-11. The dissimilarity between δ^(56)Fe profiles and profiles of [Fe] and other hydrographic tracers shows that Fe isotope ratios provide a unique sort of information about ocean chemistry, and they suggest that Fe isotopes may therefore be a valuable new tool for tracing the global sources, sinks, and biogeochemical cycling of Fe.
|Additional Information:||© 2012 American Geophysical Union. Received 27 January 2011; accepted 2 May 2012; published 15 June 2012. Thanks to all who helped and participated on the Geotraces Intercalibration I cruise, especially Chief Scientist Greg Cutter, Ed Boyle, Geoffrey Smith, and the captain and crew of the R/V Knorr.|
|Subject Keywords:||iron; isotopes; marine; seawater|
|Official Citation:||John, S. G. and J. Adkins (2012), The vertical distribution of iron stable isotopes in the North Atlantic near Bermuda, Global Biogeochem. Cycles, 26, GB2034, doi:10.1029/2011GB004043.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||11 Jul 2012 20:55|
|Last Modified:||26 Dec 2012 15:30|
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