Title An iron budget during the natural iron fertilisation experiment KEOPS (Kerguelen Islands, Southern Ocean)
Author Chever, F.; Sarthou, G.; Bucciarelli, E.; Blain, S.; Bowie, A.R.
Author Affil Chever, F., Université Européenne de Bretagne, Rennes, France. Other: Université de Brest, France; Université Pierre et Marie Curie-Paris VI, France; University of Tasmania, Australia
Source Biogeosciences, 7(2), p.455-468, . Publisher: Copernicus GmbH on behalf of the European Union, Katlenburg-Lindau, International. ISSN: 1726- 4170
Publication Date 2010
Notes In English. Part of special issue no. 46, Iron biogeochemistry across marine systems at changing times, edited by Turner, D., Hunter, K., and Riebesell, U., http://www.biogeosciences.net/special_issue46.h tml; Published in Biogeosciences Discussions: 10 July 2009, http://www.biogeosciences- discuss.net/6/6803/2009/bgd-6-6803-2009.html; accessed in Mar., 2011; abstract: doi:10.5194/bg-7-455-2010. 58 refs. Ant. Acc. No: 91634. GeoRef Acc. No: 310244
Index Terms advection; colloids; dust; metals; particles; photosynthesis; plankton; sediments; Indian Ocean Islands--Heard Island; Indian Ocean Islands--Kerguelen Islands; Southern Ocean; Antarctic Circumpolar Current; atmospheric transport; biochemistry; carbon sequestration; clastic sediments; colloidal materials; continental shelf; diffusivity; dissolved materials; eddies; Heard Island; Indian Ocean Islands; iron; Kerguelen Islands; KErguelen Ocean Plateau compared Study; nitrates; particulate materials; photochemistry; phytoplankton; productivity; sea water; transport
Abstract Total dissolvable iron (TDFe) was measured in the water column above and in the surrounding of the Kerguelen Plateau (Indian sector of the Southern Ocean) during the KErguelen Ocean Plateau compared Study (KEOPS) cruise. TDFe concentrations ranged from 0.90 to 65.6 nmol L-1 above the plateau and from 0.34 to 2.23 nmol L-1 offshore of the plateau. Station C1 located south of the plateau, near Heard Island, exhibited very high values (329-770 nmol L-1). Apparent particulate iron (Feapp), calculated as the difference between the TDFe and the dissolved iron measured on board (DFe) represented 95±5% of the TDFe above the plateau, suggesting that particles and refractory colloids largely dominated the iron pool. This paper presents a budget of DFe and Feapp above the plateau. Lateral advection of water that had been in contact with the continental shelf of Heard Island seems to be the predominant source of Feapp and DFe above the plateau, with a supply of 9.7±3.6×106 and 8.3±11.6×103 mol d-1, respectively. The residence times of 1.7 and 48 days estimated for Feapp and DFe respectively, indicate a rapid turnover in the surface water. A comparison between Feapp and total particulate iron (TPFe) suggests that the total dissolved fraction is mainly constituted of small refractory colloids. This fraction does not seem to be a potential source of iron to the phytoplankton in our study. Finally, when taking into account the lateral supply of dissolved iron, the seasonal carbon sequestration efficiency was estimated at 154 000 mol C (mol Fe)-1, which is 4-fold lower than the previously estimated value in this area but still 18-fold higher than the one estimated during the other study of a natural iron fertilisation experiment, CROZEX.
URL http://www.biogeosciences.net/7/455/2010/bg-7-455-2010.pdf
Publication Type journal article
Record ID 65007321