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| Titel |
Ocean acidification mediates photosynthetic response to UV radiation and temperature increase in the diatom Phaeodactylum tricornutum |
| VerfasserIn |
Y. Li, K. Gao, V. E. Villafañe, E. W. Helbling |
| 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. 10 ; Nr. 9, no. 10 (2012-10-12), S.3931-3942 |
| Datensatznummer |
250007329
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| Publikation (Nr.) |
 copernicus.org/bg-9-3931-2012.pdf |
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| Zusammenfassung |
| Increasing atmospheric CO2 concentration is responsible for progressive
ocean acidification, ocean warming as well as decreased thickness of upper
mixing layer (UML), thus exposing phytoplankton cells not only to lower pH
and higher temperatures but also to higher levels of solar UV radiation. In
order to evaluate the combined effects of ocean acidification, UV radiation
and temperature, we used the diatom Phaeodactylum tricornutum as a model organism and examined its
physiological performance after grown under two CO2 concentrations (390
and 1000 μatm) for more than 20 generations. Compared to the ambient
CO2 level (390 μatm), growth at the elevated CO2
concentration increased non-photochemical quenching (NPQ) of cells and
partially counteracted the harm to PS II (photosystem II) caused by UV-A and UV-B. Such
an effect was less pronounced under increased temperature levels. The ratio
of repair to UV-B induced damage decreased with increased NPQ, reflecting
induction of NPQ when repair dropped behind the damage, and it was higher
under the ocean acidification condition, showing that the increased
pCO2 and lowered pH counteracted UV-B induced harm. As for
photosynthetic carbon fixation rate which increased with increasing
temperature from 15 to 25 °C, the elevated CO2 and
temperature levels synergistically interacted to reduce the inhibition
caused by UV-B and thus increase the carbon fixation. |
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