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| Titel |
Influence of elevated CO2 concentrations on cell division and nitrogen fixation rates in the bloom-forming cyanobacterium Nodularia spumigena |
| VerfasserIn |
J. Czerny, J. Barcelos e Ramos, 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 ; 6, no. 9 ; Nr. 6, no. 9 (2009-09-04), S.1865-1875 |
| Datensatznummer |
250003990
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| Publikation (Nr.) |
 copernicus.org/bg-6-1865-2009.pdf |
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| Zusammenfassung |
| The surface ocean absorbs large quantities of the CO2 emitted to the
atmosphere from human activities. As this CO2 dissolves in seawater, it
reacts to form carbonic acid. While this phenomenon, called ocean
acidification, has been found to adversely affect many calcifying organisms,
some photosynthetic organisms appear to benefit from increasing [CO2].
Among these is the cyanobacterium Trichodesmium, a predominant diazotroph
(nitrogen-fixing) in large parts of the oligotrophic oceans, which responded
with increased carbon and nitrogen fixation at elevated pCO2. With the
mechanism underlying this CO2 stimulation still unknown, the question
arises whether this is a common response of diazotrophic cyanobacteria. In
this study we therefore investigate the physiological response of Nodularia spumigena, a
heterocystous bloom-forming diazotroph of the Baltic Sea, to
CO2-induced changes in seawater carbonate chemistry. N. spumigena reacted to
seawater acidification/carbonation with reduced cell division rates and
nitrogen fixation rates, accompanied by significant changes in carbon and
phosphorus quota and elemental composition of the formed biomass. Possible
explanations for the contrasting physiological responses of Nodularia compared to
Trichodesmium may be found in the different ecological strategies of non-heterocystous
(Trichodesmium) and heterocystous (Nodularia) cyanobacteria. |
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