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Imprint of a dissolved cobalt basaltic source on the Kerguelen Plateau

Citation

Bown, J and Boye, M and Laan, P and Bowie, AR and Park, Y-H and Jeandel, C and Nelson, DM, Imprint of a dissolved cobalt basaltic source on the Kerguelen Plateau, Biogeosciences, 9, (12) pp. 5279-5290. ISSN 1726-4170 (2012) [Refereed Article]


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Licenced under Creative Commons Attribution 3.0 License (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/

DOI: doi:10.5194/bg-9-5279-2012

Abstract

Processes of cobalt (Co) entrainment from shelf sediments over the Kerguelen Plateau were studied during the KEOPS (Kerguelen Ocean Plateau compared Study) in order to explain the exceptionally high dissolved cobalt concentrations that have been measured in the surface waters above the Kerguelen Plateau, and in intermediate and deep waters above its eastern slope. Lateral advection and dissolution of Co contained in basalt sediments around Heard Island, a main source of lithogenic Co in the study area, were shown to imprint the process of surface enrichment over the plateau. Dissolved Co enrichment was strongest at the intercept of the eastern slope with intermediate and deep waters, probably due to more efficient mobilisation of the sediments in the slope current, in addition to advection of Co-enriched and low-oxygenated ocean water masses.

In surface waters, the strong sedimentary Co inputs were estimated to be much higher than biological Co uptake in phytoplankton blooms, underlining the potential use of dissolved cobalt as tracer of the natural iron fertilization above the Kerguelen Plateau. Based on a simple steady-state balance equation of the external input of dissolved iron over the plateau, the fertilization of iron inferred by using dissolved Co as a tracer of basalt sources is estimated to be 28 × 102 ± 21 × 102 t yr−1 in surface waters of the Kerguelen Plateau. This estimate is consistent with preceding ones (Zhang et al., 2008; Chever et al., 2010), and the calculated iron supply matches with the phytoplankton demand (Sarthou et al., 2008).

Item Details

Item Type:Refereed Article
Keywords:Cobalt, Kerguelen plateau, iron fertilisation
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical Oceanography
Objective Division:Environment
Objective Group:Physical and Chemical Conditions of Water
Objective Field:Physical and Chemical Conditions of Water in Marine Environments
Author:Bowie, AR (Associate Professor Andrew Bowie)
ID Code:83159
Year Published:2012
Funding Support:Australian Research Council (LE0989539)
Web of Science® Times Cited:4
Deposited By:IMAS Research and Education Centre
Deposited On:2013-03-04
Last Modified:2013-06-13
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