Physical speciation of iron in the Atlantic sector of the Southern Ocean along a transect from the subtropical domain to the Weddell Sea Gyre.

International audience Distributions of total dissolvable iron (TDFe; unfiltered), dissolved iron (DFe; 0.2 μm filtered), and soluble iron (SFe; 0.02 μm filtered) were investigated during the BONUS‐GoodHope cruise in the Atlantic sector of the Southern Ocean (34°S/17°E-57°S/0°, February-March 2008)....

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Published in:Journal of Geophysical Research: Oceans
Main Authors: Chever, Fanny, Bucciarelli, Eva, Sarthou, Géraldine, Speich, Sabrina, Arhan, Michel, Penven, Pierrick, Tagliabue, Alessandro
Other Authors: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2010
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Online Access:https://hal.science/hal-00588791
https://hal.science/hal-00588791/document
https://hal.science/hal-00588791/file/2009JC005880.pdf
https://doi.org/10.1029/2009JC005880
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Summary:International audience Distributions of total dissolvable iron (TDFe; unfiltered), dissolved iron (DFe; 0.2 μm filtered), and soluble iron (SFe; 0.02 μm filtered) were investigated during the BONUS‐GoodHope cruise in the Atlantic sector of the Southern Ocean (34°S/17°E-57°S/0°, February-March 2008). In the mixed layer, mean values of 0.43 ± 0.28 and 0.22 ± 0.18 nmol L −1 were measured for TDFe and DFe, respectively. In deeper waters, TDFe and DFe concentrations were 1.07 ± 0.68 and 0.52 ± 0.30 nmol L −1 , respectively. DFe concentrations decreased from the north (subtropical waters) to the south (Weddell Sea Gyre). In the subtropical domain, dusts coming from Patagonia and southern Africa and inputs from the African continental margin may explain high DFe and TDFe concentrations in surface and intermediate waters. Results from numerical models gave support to these hypotheses. In the Antarctic Circumpolar Current domain, estimation of the median advective time of water masses suggests that sediment inputs from the Antarctic Peninsula, South America margin, and/or South Georgia Islands could be an important source of Fe. Except in the subtropical domain where 0.4-0.6 nmol L −1 of SFe were observed in the upper 1500 m, all stations exhibited values close to 0.1-0.2 nmol L −1 in surface and 0.3-0.5 nmol L −1 in deeper waters. For all stations, colloidal Fe (CFe) was a minor fraction of DFe in surface waters and increased with depth. Colloidal aggregation, sinking of CFe, and assimilation of SFe, followed by rapid exchange between the two fractions, are suspected to occur.