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| Titel |
Diatoms and their influence on the biologically mediated uptake of atmospheric CO2 in the Arabian Sea upwelling system |
| VerfasserIn |
T. Rixen, C. Goyet, V. Ittekkot |
| 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 ; 3, no. 1 ; Nr. 3, no. 1 (2006-01-09), S.1-13 |
| Datensatznummer |
250000727
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| Publikation (Nr.) |
 copernicus.org/bg-3-1-2006.pdf |
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| Zusammenfassung |
| Sediment trap experiments have been carried out in order to study processes
controlling shifts from diatom to non-diatom dominated systems in the
western Arabian Sea. One of our major problems was to link sediment trap
records to surface ocean processes. Satellite-derived observations on upper
ocean parameters were helpful to reduce this problem in the past and gain a
new quality by combining it with results obtained during the Joint Global
Ocean Flux Study (JGOFS) in the Arabian Sea. The new results imply that
intense grazing can decline or impede the development of large diatom blooms
in a silicon-enriched near shore upwelling system off Oman. In the open
western Arabian Sea diatom blooms recover within the offshore advecting
upwelled water and lead to peak organic fluxes into the deep sea but only
during the later phase of the upwelling season. During onset of the
upwelling season grazing favoured by eolian iron inputs causing the
formation of thinner diatom shells seems to prevent the development of a
large diatom bloom within the silicon-enriched offshore advecting upwelled
water. An increased relevance of diatoms and diatom-grazing copepods in the
planktonic community as well as oligotrophic conditions seem to raise the
ratio between organic carbon formation and calcium carbonate carbon
precipitation (rain ratio) in the surface water. The decomposition of
organic matter in the water column reduces the rain ratio within in the
sinking matter especially in the oligotrophic region dominated by
cyanobacteria and reduces also the variation of the carbon to nutrient
uptake ratios seen in the surface water. |
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