Publication Date:
2022-05-26
Description:
Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 28 (2014): 1387–1412, doi:10.1002/2014GB004903.
Description:
Dissolved cobalt (DCo; 〈0.2 µm; 14 to 93 pM) and the apparent particulate cobalt (PCo; 〉0.2 µm; 〈1 to 15 pM) were determined in the upper water column (〈1000 m) of the western Atlantic Ocean along the GEOTRACES-A02 section (64°N to 50°S). The lowest DCo concentrations, typical of a nutrient-type distribution were observed in surface waters of the subtropical domains. Strong linear relationships between DCo and phosphate (P) as well as meridional gradients of decreasing DCo from high latitudes were characterized and both linked to the Co biological requirement. External sources such as the Amazon and the atmospheric deposition were found to contribute significantly (〉10%) to the DCo stock of the mixed layer in the equatorial and north subtropical domains. Biotic and abiotic processes as well as the physical terms involved in the biogeochemical cycle of Co were defined and estimated. This allowed establishing the first global budget of DCo for the upper 100 m in the western Atlantic. The biological DCo uptake flux was the dominant sink along the section, as reflected by the overall nutrient-type behavior of DCo. The regeneration varied widely within the different biogeochemical domains, accounting for 10% of the DCo-uptake rate in the subarctic gyre and for up to 85% in southern subtropical domain. These findings demonstrated that the regeneration is likely the prevailing source of DCo in the surface waters of the western Atlantic, except in the subpolar domains where physically driven sources can sustain the DCo biological requirement.
Description:
This investigation was supported by the GEOTRACES-GEOSECS revisited in the West Atlantic project coordinated by M. Boye and funded by the French LEFE-CYBER National Program of the Institut National des Sciences de l'Univers (INSU). We also acknowledge the European COST-Action ES801 for funding a short-term Scientific Mission to G. Dulaquais to join the last cruise of the GEOTRACES-A02 section. The Université de Bretagne Occidentale (UBO) and the Région Bretagne (ARED) are supporting the PhD fellowship of G. Dulaquais. P.M. was supported in part by a Gledden Visiting Fellowship awarded by the Institute of Advanced Studies at The University of Western Australia.
Description:
2015-06-05
Keywords:
Cobalt
;
Biogeochemistry
;
Atlantic Ocean
;
Chemical Oceanography
;
GEOTRACES
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
Format:
application/msword
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