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Natural iron fertilization of the Atlantic sector of the Southern Ocean by continental shelf sources of the Antarctic Peninsula


de Jong, J and Schoemann, V and Lannuzel, D and Croot, P and de Baar, H and Tison, J-L, Natural iron fertilization of the Atlantic sector of the Southern Ocean by continental shelf sources of the Antarctic Peninsula, Journal of Geophysical Research G: Biogeosciences, 117, (1) Article G01029. ISSN 0148-0227 (2012) [Refereed Article]

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Copyright 2012 the American Geophysical Union

DOI: doi:10.1029/2011JG001679


In large parts of the Southern Ocean, primary production is limited due to shortage of iron (Fe). We measured vertical Fe profiles in the western Weddell Sea, Weddell-Scotia Confluence, and Antarctic Circumpolar Current (ACC), showing that Fe is derived from benthic Fe diffusion and sediment resuspension in areas characterized by high turbulence due to rugged bottom topography. Our data together with literature data reveal an exponential decrease of dissolved Fe (DFe) concentrations with increasing distance from the continental shelves of the Antarctic Peninsula and the western Weddell Sea. This decrease can be observed 3500 km eastward of the Antarctic Peninsula area, downstream the ACC. We estimated DFe summer fluxes into the upper mixed layer of the Atlantic sector of the Southern Ocean and found that horizontal advection dominates DFe supply, representing 54 15% of the total flux, with significant vertical advection second most important at 29 13%. Horizontal and vertical diffusion are weak with 1 2% and 1 1%, respectively. The atmospheric contribution is insignificant close to the Antarctic continent but increases to 15 10% in the remotest waters (>1500 km offshore) of the ACC. Translating Southern Ocean carbon fixation by primary producers into biogenic Fe fixation shows a twofold excess of new DFe input close to the Antarctic continent and a one-third shortage in the open ocean. Fe recycling, with an estimated "fe" ratio of 0.59, is the likely pathway to balance new DFe supply and Fe fixation.

Item Details

Item Type:Refereed Article
Keywords:iron fertilization, Southern Ocean, continental shelf
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:Lannuzel, D (Associate Professor Delphine Lannuzel)
ID Code:80539
Year Published:2012
Web of Science® Times Cited:100
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2012-11-02
Last Modified:2015-08-11
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