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| Titel |
Forcing of dissolved organic carbon release by phytoplankton by anticyclonic mesoscale eddies in the subtropical NE Atlantic Ocean |
| VerfasserIn |
S. Lasternas, M. Piedeleu, P. Sangrà, C. M. Duarte, S. Agustí  |
| 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 ; 10, no. 3 ; Nr. 10, no. 3 (2013-03-27), S.2129-2143 |
| Datensatznummer |
250018175
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| Publikation (Nr.) |
 copernicus.org/bg-10-2129-2013.pdf |
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| Zusammenfassung |
| The organic carbon fluxes mediated by planktonic communities in two cyclonic
eddies (CEs) and two anticyclonic eddies (AEs) at the Canary Eddy Corridor
were studied and compared with the dynamics in two far-field (FF) stations
located outside the eddies. We observed favorable conditions and signs for
upwelling at the center of CEs and for downwelling and mixing at the centers
of AEs. CEs were characterized by a higher concentration of nutrients and
the highest concentration of chlorophyll a (chl a), associated with the highest
abundance of microphytoplankton and diatoms. AEs displayed concentrations of
chl a values and nutrients similar to those at the FF stations, except
for the highest ammonium concentration occurring at AE and a very low concentration of
phosphorus at FF stations. AEs were transient systems characterized by an increasing
abundance of picophytoplankton and heterotrophic bacteria. While primary
production was similar between the systems, the production of dissolved
organic carbon (PDOC) was significantly higher in the AEs. Phytoplankton
cell mortality was lowest in the CEs, and we found higher cell mortality rates at
AE than at FF stations, despite similar chl a concentration. Environmental changes
in the AEs have been significantly prejudicial to phytoplankton as indicated by
higher phytoplankton cell mortality (60% of diatoms cells were dead) and
higher cell lysis rates. The adverse conditions for phytoplankton associated
with the early-stage anticyclonic systems, mainly triggered by active
downwelling, resulted in higher cell mortality, forcing photosynthesized
carbon to fuel the dissolved pool. |
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