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| Titel |
An iron budget during the natural iron fertilisation experiment KEOPS (Kerguelen Islands, Southern Ocean) |
| VerfasserIn |
F. Chever, G. Sarthou, E. Bucciarelli, S. Blain, A. R. Bowie |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 2 ; Nr. 7, no. 2 (2010-02-02), S.455-468 |
| Datensatznummer |
250004482
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| Publikation (Nr.) |
 copernicus.org/bg-7-455-2010.pdf |
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| Zusammenfassung |
| 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. |
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