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| Titel |
Phytoplankton competition during the spring bloom in four plankton functional type models |
| VerfasserIn |
T. Hashioka, M. Vogt, Y. Yamanaka, C. Quéré, E. T. Buitenhuis, M. N. Aita, S. Alvain, L. Bopp, T. Hirata, I. Lima, S. Sailley, S. C. Doney |
| 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. 11 ; Nr. 10, no. 11 (2013-11-02), S.6833-6850 |
| Datensatznummer |
250085386
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| Publikation (Nr.) |
 copernicus.org/bg-10-6833-2013.pdf |
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| Zusammenfassung |
| We investigated the mechanisms of phytoplankton competition during the
spring bloom, one of the most dramatic seasonal events in lower-trophic-level
ecosystems, in four state-of-the-art plankton functional type (PFT)
models: PISCES, NEMURO, PlankTOM5 and CCSM-BEC. In particular, we
investigated the relative importance of different ecophysiological processes
on the determination of the community structure, focusing both on the
bottom-up and the top-down controls. The models reasonably reproduced the
observed global distribution and seasonal variation of phytoplankton
biomass. The fraction of diatoms with respect to the total phytoplankton
biomass increases with the magnitude of the spring bloom in all models.
However, the governing mechanisms differ between models, despite the fact
that current PFT models represent ecophysiological processes using the same
types of parameterizations. The increasing trend in the percentage of
diatoms with increasing bloom magnitude is mainly caused by a stronger
nutrient dependence of diatom growth compared to nanophytoplankton
(bottom-up control). The difference in the maximum growth rate plays an
important role in NEMURO and PlankTOM5 and determines the absolute values of
the percentage of diatoms during the bloom. In CCSM-BEC, the light
dependency of growth plays an important role in the North Atlantic and the
Southern Ocean. The grazing pressure by zooplankton (top-down control),
however, strongly contributes to the dominance of diatoms in PISCES and
CCSM-BEC. The regional differences in the percentage of diatoms in PlankTOM5
are mainly determined by top-down control. These differences in the
mechanisms suggest that the response of marine ecosystems to climate change
could significantly differ among models, even if the present-day ecosystem
is reproduced to a similar degree of confidence. For further understanding
of plankton competition and for the prediction of future change in marine
ecosystems, it is important to understand the relative differences in each
physiological rate and life history rate in the bottom-up and the top-down
controls between PFTs. |
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