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| Titel |
Reviews and Syntheses: Responses of coccolithophores to ocean acidification: a meta-analysis |
| VerfasserIn |
J. Meyer, U. Riebesell |
| 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. 6 ; Nr. 12, no. 6 (2015-03-16), S.1671-1682 |
| Datensatznummer |
250117861
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| Publikation (Nr.) |
 copernicus.org/bg-12-1671-2015.pdf |
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| Zusammenfassung |
| Concerning their sensitivity to ocean acidification, coccolithophores, a
group of calcifying single-celled phytoplankton, are one of the best-studied
groups of marine organisms. However, in spite of the large number of studies
investigating coccolithophore physiological responses to ocean
acidification, uncertainties still remain due to variable and partly
contradictory results. In the present study we have used all existing data
in a meta-analysis to estimate the effect size of future pCO2 changes
on the rates of calcification and photosynthesis and the ratio of
particulate inorganic to organic carbon (PIC / POC) in different
coccolithophore species. Our results indicate that ocean acidification has a
negative effect on calcification and the cellular PIC / POC ratio in the two most
abundant coccolithophore species: Emiliania huxleyi and Gephyrocapsa oceanica. In contrast, the more heavily
calcified species Coccolithus braarudii did not show a distinct response when exposed to elevated
pCO2/reduced pH. Photosynthesis in Gephyrocapsa oceanica was positively affected by high
CO2, while no effect was observed for the other coccolithophore
species. There was no indication that the method of carbonate chemistry
manipulation was responsible for the inconsistent results regarding observed
responses in calcification and the PIC / POC ratio. The perturbation method,
however, appears to affect photosynthesis, as responses varied significantly
between total alkalinity (TA) and dissolved inorganic carbon (DIC)
manipulations. These results emphasize that coccolithophore species respond
differently to ocean acidification, both in terms of calcification and
photosynthesis. Where negative effects occur, they become evident at
CO2 levels in the range projected for this century in the case of unabated
CO2 emissions. As the data sets used in this meta-analysis do not
account for adaptive responses, ecological fitness and ecosystem
interactions, the question remains as to how these physiological responses play
out in the natural environment. |
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