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| Titel |
Large-scale shifts in phytoplankton groups in the Equatorial Pacific during ENSO cycles |
| VerfasserIn |
I. Masotti, C. Moulin, S. Alvain, L. Bopp, A. Tagliabue, D. Antoine |
| 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 ; 8, no. 3 ; Nr. 8, no. 3 (2011-03-04), S.539-550 |
| Datensatznummer |
250005561
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| Publikation (Nr.) |
 copernicus.org/bg-8-539-2011.pdf |
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| Zusammenfassung |
| The El Niño Southern Oscillation (ENSO) drives important changes in the
marine productivity of the Equatorial Pacific, in particular during major El
Niño/La Niña transitions. Changes in environmental conditions
associated with these climatic events also likely impact phytoplankton
composition. In this work, the distribution of four major phytoplankton
groups (nanoeucaryotes, Prochlorococcus, Synechococcus, and diatoms) was
examined between 1996 and 2007 by applying the PHYSAT algorithm to the ocean
color data archive from the Ocean Color and Temperature Sensor (OCTS) and
Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Coincident with the
decrease in chlorophyll concentrations, a large-scale shift in the
phytoplankton composition of the Equatorial Pacific, that was characterized
by a decrease in Synechococcus and an increase in nanoeucaryote dominance,
was observed during the early stages of both the strong El Niño of 1997
and the moderate El Niño of 2006. A significant increase in diatoms
dominance was observed in the Equatorial Pacific during the 1998 La Niña
and was associated with elevated marine productivity. An analysis of the
environmental variables using a coupled physical-biogeochemical model
(NEMO-PISCES) suggests that the Synechococcus dominance decrease during the
two El Niño events was associated with an abrupt decline in nutrient
availability (−0.9 to −2.5 μM NO3 month−1). Alternatively,
increased nutrient availability (3 μM NO3 month−1) during the
1998 La Niña resulted in Equatorial Pacific dominance diatom increase.
Despite these phytoplankton community shifts, the mean composition is
restored after a few months, which suggests resilience in community
structure. |
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