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| Titel |
Spatial distribution of the iron supply to phytoplankton in the Southern Ocean: a model study |
| VerfasserIn |
C. Lancelot, A. Montety, H. Goosse, S. Becquevort, V. Schoemann, B. Pasquer, M. Vancoppenolle |
| 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 ; 6, no. 12 ; Nr. 6, no. 12 (2009-12-07), S.2861-2878 |
| Datensatznummer |
250004218
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| Publikation (Nr.) |
 copernicus.org/bg-6-2861-2009.pdf |
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| Zusammenfassung |
| An upgraded version of the biogeochemical model SWAMCO is coupled to the
ocean-sea-ice model NEMO-LIM to explore processes governing the spatial
distribution of the iron supply to phytoplankton in the Southern Ocean. The
3-D NEMO-LIM-SWAMCO model is implemented in the ocean domain south of
latitude 30° S and runs are performed over September 1989–December 2000. Model scenarios include potential iron sources (atmospheric
deposition, iceberg calving/melting and continental sediments) as well as
iron storage within sea ice, all formulated based on a literature review.
When all these processes are included, the simulated iron profiles and
phytoplankton bloom distributions show satisfactory agreement with
observations. Analyses of simulations and sensitivity tests point to the key
role played by continental sediments as a primary source for iron. Iceberg
calving and melting contribute by up to 25% of Chl-a simulated in areas
influenced by icebergs while atmospheric deposition has little effect at
high latitudes. Activating sea ice-ocean iron exchanges redistribute iron
geographically. Stored in the ice during winter formation, iron is then
transported due to ice motion and is released and made available to
phytoplankton during summer melt, in the vicinity of the marginal ice zones.
Transient iron storage and transport associated with sea ice dynamics
stimulate summer phytoplankton blooming (up to 3 mg Chl-a m-3 in the
Weddell Sea and off East Antarctica but not in the Ross, Bellingshausen and
Amundsen Seas. This contrasted feature results from the simulated variable
content of iron in sea ice and release of melting ice showing higher
ice-ocean iron fluxes in the continental shelves of the Weddell and Ross
Seas than in the Eastern Weddell Sea and the Bellingshausen-Amundsen Seas.
This study confirms that iron sources and transport in the Southern Ocean
likely provide important mechanisms in the geographical development of
phytoplankton blooms and associated ecosystems. |
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