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Titel |
New insights into the organic carbon export in the Mediterranean Sea from 3-D modeling |
VerfasserIn |
A. Guyennon, M. Baklouti, F. Diaz, J. Palmieri, J. Beuvier, C. Lebaupin-Brossier, T. Arsouze, K. Béranger, J.-C. Dutay, T. Moutin |
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 ; 12, no. 23 ; Nr. 12, no. 23 (2015-12-07), S.7025-7046 |
Datensatznummer |
250118197
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Publikation (Nr.) |
copernicus.org/bg-12-7025-2015.pdf |
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Zusammenfassung |
The Mediterranean Sea is one of the most oligotrophic regions of the oceans,
and nutrients have been shown to limit both phytoplankton and bacterial
activities, resulting in a potential major role of dissolved organic carbon
(DOC) export in the biological pump.
Strong DOC accumulation in surface waters
is already
well documented,
though
measurements of DOC stocks and export flux are still sparse and
associated with major uncertainties. This study provides the first
basin-scale overview and analysis of organic carbon stocks and export fluxes
in the Mediterranean Sea through a modeling approach based on a coupled
model combining a mechanistic biogeochemical model (Eco3M-MED) and a
high-resolution (eddy-resolving) hydrodynamic simulation (NEMO-MED12). The
model is shown to reproduce the main spatial and seasonal biogeochemical
characteristics of the Mediterranean Sea. Model estimations of carbon export
are also of the same order of magnitude as estimations from in situ
observations, and their respective spatial patterns are mutually
consistent. Strong differences between the western and eastern basins are
evidenced by the model for organic carbon export. Though less oligotrophic
than the eastern basin, the western basin only supports
39 % of organic carbon (particulate and dissolved) export.
Another major result is that except for the Alboran Sea, the DOC
contribution to organic carbon export is higher than that of particulate
organic carbon (POC) throughout
the
Mediterranean Sea,
especially in the eastern basin.
This paper also investigates the seasonality of DOC and POC exports as well
as the differences in the processes involved in DOC and POC exports in
light of intracellular quotas. Finally, according to the model, strong
phosphate limitation of both bacteria and phytoplankton growth is
one of the main drivers of DOC accumulation and therefore of export. |
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