Publication Date:
2022-05-25
Description:
Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 55 (2008): 1473-1490, doi:10.1016/j.dsr2.2008.02.010.
Description:
The vertical distributions of cobalt, iron, and manganese in the water column were
studied during the E-Flux Program (E-Flux II and III), which focused on the
biogeochemistry of cold-core cyclonic eddies that form in the lee of the Hawaiian
Islands. During E-Flux II (January 2005) and E-Flux III (March 2005), 17 stations were
sampled for cobalt (n =147), all of which demonstrated nutrient-like depletion in surface
waters. During E-Flux III, two depth profiles collected from within a mesoscale coldcore
eddy, Cyclone Opal, revealed small distinct maxima in cobalt at ~100m depth and a
larger inventory of cobalt within the eddy. We hypothesize that this was due to a cobalt
concentrating effect within the eddy, where upwelled cobalt was subsequently associated
with sinking particulate organic carbon (POC) via biological activity and was released at
a depth coincident with nearly complete POC remineralization (Benitez-Nelson et al.
2007). There is also evidence for the formation of a correlation between cobalt and
soluble reactive phosphorus during E-Flux III relative to the E-Flux II cruise that we
suggest is due to increased productivity, implying a minimum threshold of primary
production below which cobalt-phosphate coupling does not occur. Dissolved iron was
measured in E-Flux II and found in somewhat elevated concentrations (~0.5nM) in
surface waters relative to the iron depleted waters of the surrounding Pacific (Fitzwater et
al. 1996), possibly due to island effects associated with the iron-rich volcanic soil from
the Hawaiian Islands and/or anthropogenic inputs. Distinct depth maxima in total
dissolved cobalt were observed at 400 to 600m depth, suggestive of the release of metals
from the shelf area of comparable depth that surrounds these islands.
Description:
This research was supported by NSF Grants
OCE-0327225, OCE-0452883, OPP-0440840, the Office of Naval Research, the Center
for Environmental Bioinorganic Chemistry at Princeton, and the Center for Microbial
Oceanography and Education.
Keywords:
Hybrid-type metals
;
Cobalt
;
Iron
;
Manganese
;
Trace metal biogeochemistry
;
Lee eddies
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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