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Estimating the benthic efflux of dissolved iron on the Ross Sea continental shelf
Author(s) -
Marsay C. M.,
Sedwick P. N.,
Dinniman M. S.,
Barrett P. M.,
Mack S. L.,
McGillicuddy D. J.
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl061684
Subject(s) - continental shelf , benthic zone , oceanography , photic zone , seafloor spreading , continental margin , geology , bathymetry , environmental science , paleontology , ecology , nutrient , biology , phytoplankton , tectonics
Continental margin sediments provide a potentially large but poorly constrained source of dissolved iron (dFe) to the upper ocean. The Ross Sea continental shelf is one region where this benthic supply is thought to play a key role in regulating the magnitude of seasonal primary production. Here we present data collected during austral summer 2012 that reveal contrasting low surface (0.08 ± 0.07 nM) and elevated near‐seafloor (0.74 ± 0.47 nM) dFe concentrations. Combining these observations with results from a high‐resolution physical circulation model, we estimate dFe efflux of 5.8 × 10 7 mol yr −1 from the deeper portions (>400 m) of the Ross Sea continental shelf; more than sufficient to account for the inferred “winter reserve” dFe inventory at the onset of the growing season. In addition, elevated dFe concentrations observed over shallower bathymetry suggest that such features provide additional inputs of dFe to the euphotic zone throughout the year.