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| Titel |
A hypothesis linking sub-optimal seawater pCO2 conditions for cnidarian-Symbiodinium symbioses with the exceedence of the interglacial threshold (>260 ppmv) |
| VerfasserIn |
S. A. Wooldridge |
| 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. 5 ; Nr. 9, no. 5 (2012-05-15), S.1709-1723 |
| Datensatznummer |
250007025
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| Publikation (Nr.) |
 copernicus.org/bg-9-1709-2012.pdf |
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| Zusammenfassung |
| Most scleractinian corals and many other cnidarians host intracellular
photosynthetic dinoflagellate symbionts ("zooxanthellae"). The zooxanthellae
contribute to host metabolism and skeletogenesis to such an extent that this
symbiosis is well recognised for its contribution in creating the coral reef
ecosystem. The stable functioning of cnidarian symbioses is however
dependent upon the host's ability to maintain demographic control of its
algal partner. In this review, I explain how the modern envelope of seawater
conditions found within many coral reef ecosystems (characterised by
elevated temperatures, rising pCO2, and enriched nutrient levels) are
antagonistic toward the dominant host processes that restrict excessive
symbiont proliferation. Moreover, I outline a new hypothesis and initial
evidence base, which support the suggestion that the additional "excess"
zooxanthellae fraction permitted by seawater pCO2 levels beyond 260 ppmv
significantly increases the propensity for symbiosis breakdown
("bleaching") in response to temperature and irradiance extremes. The
relevance of this biological threshold is discussed in terms of historical
reef extinction events, glacial-interglacial climate cycles and the modern
decline of coral reef ecosystems. |
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