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| Titel |
Synergism between elevated pCO2 and temperature on the Antarctic sea ice diatom Nitzschia lecointei |
| VerfasserIn |
A. Torstensson, M. Hedblom, J. Andersson, M. X. Andersson, A. Wulff |
| 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 ; 10, no. 10 ; Nr. 10, no. 10 (2013-10-09), S.6391-6401 |
| Datensatznummer |
250085357
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| Publikation (Nr.) |
 copernicus.org/bg-10-6391-2013.pdf |
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| Zusammenfassung |
| Polar oceans are particularly susceptible to ocean acidification and warming.
Diatoms play a significant role in sea ice biogeochemistry and provide an
important food source to grazers in ice-covered oceans, especially during
early spring. However, the ecophysiology of ice-living organisms has received
little attention in terms of ocean acidification. In this study, the
synergism between temperature and partial pressure of CO2 (pCO2)
was investigated in relationship to the optimal growth temperature of the
Antarctic sea ice diatom Nitzschia lecointei. Diatoms were kept in
cultures at controlled levels of pCO2 (∼390 and
∼960 μatm) and temperature (−1.8 and 2.5 °C) for
14 days. Synergism between temperature and pCO2 was detected in growth
rate and acyl lipid fatty acid (FA) content. Optimal growth rate was observed
around 5 °C in a separate experiment. Carbon enrichment only
promoted (6%) growth rate closer to the optimal growth, but not at the
control temperature (−1.8 °C). At −1.8 °C and at
∼960 μatm pCO2, the total FA content was reduced
relative to the ∼390 μatm treatment, although no difference
between pCO2 treatments was observed at 2.5 °C. A large
proportion (97%) of the total FAs comprised on average of
polyunsaturated fatty acids (PUFA) at −1.8 °C. Cellular PUFA
content was reduced at ∼960 relative to ∼390 μatm
pCO2. Effects of carbon enrichment may be different depending on ocean
warming scenario or season, e.g. reduced cellular FA content in response to
elevated CO2 at low temperatures only, reflected as reduced food quality
for higher trophic levels. Synergy between warming and acidification may be
particularly important in polar areas since a narrow thermal window generally
limits cold-water organisms. |
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