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- Title
British Columbian continental shelf as a source of dissolved iron to the subarctic northeast Pacific Ocean.
- Authors
Cullen, Jay T.; Chong, Marina; Ianson, Debby
- Abstract
The distribution of dissolved (<0.4 μm) iron (Fe) across the continental shelf and slope of Queen Charlotte Sound on the west coast of Canada was examined to estimate the potential of these waters as a source of Fe to the Fe-limited waters of the subarctic northeast Pacific. Iron profiles obtained in shelf, slope, and offshore waters demonstrate decreasing concentrations of Fe with distance from the continent. Within 50 m of the shelf sediments dissolved Fe concentrations were 5.3 ± 0.3 nM. This signal was detected, although attenuated by 80%, along the isopycnal surface at offshore stations 40-50 km seaward of the shelf break, strongly suggesting cross-shelf transport of an Fe-rich plume originating in low dissolved oxygen (<3 ml L-1, <130 μmol kg-1) waters in subsurface water over the continental shelf. Several physical mechanisms that may cause these Fe-enriched waters to advect offshore in this region (i.e., tidal currents and Ekman transport in the bottom boundary layer, coastal downwelling/relaxation from upwelling, and the formation of anticyclonic, westward-propagating, coastal eddies) are discussed. We suggest that strong tidal currents over broad continental shelves may play a key role in Fe supply to ocean basins.
- Subjects
BRITISH Columbia; QUEEN Charlotte Sound (B.C.); IRON content of seawater; COMPOSITION of water; TIDAL currents; ANTICYCLONES; EDDIES
- Publication
Global Biogeochemical Cycles, 2009, Vol 23, Issue 4, pGB4012
- ISSN
0886-6236
- Publication type
Article
- DOI
10.1029/2008GB003326