High variability in dissolved iron concentrations in the vicinity of the Kerguelen Islands (Southern Ocean)
|Author(s)||Queroue Fabien1, 2, 3, 4, Sarthou Geraldine2, Planquette Helene2, Bucciarelli Eva1, 2, Chever Fanny2, Van Der Merwe P.4, Lannuzel Delphine3, 4, Townsend A. T.5, Cheize Marie2, Blain S.6, 7, D'Ovidio F.8, Bowie A. R.3, 4|
|Affiliation(s)||1 : Univ Bretagne Occidentale, IUEM, F-29200 Brest, France.
2 : IFREMER, IRD, UBO, LEMAR,UMR 6539,CNRS, F-29280 Plouzane, France.
3 : Univ Tasmania, Inst Marine & Antarctic Studies, Hobart, Tas 7001, Australia.
4 : Univ Tasmania, Antarctic Climate & Ecosyst Cooperat Res Ctr, Hobart, Tas 7001, Australia.
5 : Univ Tasmania, Cent Sci Lab, Hobart, Tas 7001, Australia.
6 : Univ Paris 06, Lab Oceanog Biol Banyuls Mer, F-66650 Banyuls Sur Mer, France.
7 : CNRS, Lab Oceanog Biol Banyuls Mer, F-66650 Banyuls Sur Mer, France.
8 : Univ Paris 06, Univ Paris 04, CNRS, IRD,MNHN,LOCEAN,IPSL, F-75005 Paris, France.
|Source||Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2015 , Vol. 12 , N. 12 , P. 3869-3883|
|WOS© Times Cited||21|
|Note||KEOPS2: Kerguelen Ocean and Plateau Study 2 Editor(s): S. Blain, I. Obernosterer, B. Queguiner, T. Trull, and G. Herndl|
|Abstract||Dissolved Fe (dFe) concentrations were measured in the upper 1300 m of the water column in the vicinity of the Kerguelen Islands as part of the second KErguelen Ocean Plateau compared Study (KEOPS2). Concentrations ranged from 0.06 nmol L-1 in offshore, Southern Ocean waters to 3.82 nmol L-1 within Hillsborough Bay, on the north-eastern coast of the Kerguelen Islands. Direct island runoff, glacial melting and resuspended sediments were identified as important inputs of dFe that could potentially fertilise the northern part of the plateau. A significant deep dFe enrichment was observed over the plateau with dFe concentrations increasing up to 1.30 nmol L-1 close to the seafloor, probably due to sediment resuspension and pore water release. Biological uptake was shown to induce a significant decrease in dFe concentrations between two visits (28 days apart) at a station above the plateau. Our work also considered other processes and sources, such as lateral advection of enriched seawater, remineralisation processes, and the influence of the polar front (PF) as a vector for Fe transport. Overall, heterogeneous sources of Fe over and off the Kerguelen Plateau, in addition to strong variability in Fe supply by vertical or horizontal transport, may explain the high variability in dFe concentrations observed during this study.|