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| Titel |
Enhanced carbon overconsumption in response to increasing temperatures during a mesocosm experiment |
| VerfasserIn |
Jan Taucher, K. G. Schulz, T. Dittmar, U. Sommer, A. Oschlies, 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 ; 9, no. 9 ; Nr. 9, no. 9 (2012-09-05), S.3531-3545 |
| Datensatznummer |
250007286
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| Publikation (Nr.) |
 copernicus.org/bg-9-3531-2012.pdf |
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| Zusammenfassung |
| Increasing concentrations of atmospheric carbon dioxide are projected to lead
to an increase in sea surface temperatures, potentially impacting marine
ecosystems and biogeochemical cycling. Here we conducted an indoor mesocosm
experiment with a natural plankton community taken from the Baltic Sea in
summer. We induced a plankton bloom via nutrient addition and followed the
dynamics of the different carbon and nitrogen pools for a period of one month
at temperatures ranging from 9.5 °C to 17.5 °C, representing
a range of ±4 °C relative to ambient temperature. The uptake of
dissolved inorganic carbon (DIC) and the net build-up of both particulate
(POC) and dissolved organic carbon (DOC) were all enhanced at higher
temperatures and almost doubled over a temperature gradient of 8 °C.
Furthermore, elemental ratios of carbon and nitrogen (C : N) in both
particulate and dissolved organic matter increased in response to higher
temperatures, both reaching very high C : N ratios of > 30 at
+4 °C. Altogether, these observations suggest a pronounced increase
in excess carbon fixation in response to elevated temperatures. Most of these
findings are contrary to results from similar experiments conducted with
plankton populations sampled in spring, revealing large uncertainties in our
knowledge of temperature sensitivities of key processes in marine carbon
cycling. Since a major difference to previous mesocosm experiments was the
dominant phytoplankton species, we hypothesize that species composition might
play an important role in the response of biogeochemical cycling to
increasing temperatures. |
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