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British Columbian continental shelf as a source of dissolved iron to the subarctic northeast Pacific Ocean.
- Source :
- Global Biogeochemical Cycles; Dec2009, Vol. 23 Issue 4, pGB4012-1NULL, 12p, 5 Graphs
- Publication Year :
- 2009
-
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<superscript>-1</superscript>, <130 μmol kg<superscript>-1</superscript>) 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. [ABSTRACT FROM AUTHOR]
- Subjects :
- IRON content of seawater
COMPOSITION of water
TIDAL currents
ANTICYCLONES
EDDIES
Subjects
Details
- Language :
- English
- ISSN :
- 08866236
- Volume :
- 23
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Global Biogeochemical Cycles
- Publication Type :
- Academic Journal
- Accession number :
- 48357378
- Full Text :
- https://doi.org/10.1029/2008GB003326