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| Titel |
Effect of increased pCO2 on the planktonic metabolic balance during a mesocosm experiment in an Arctic fjord |
| VerfasserIn |
T. Tanaka, S. Alliouane, R. G. B. Bellerby, J. Czerny, A. Kluijver, U. Riebesell, K. G. Schulz, A. Silyakova, J.-P. Gattuso |
| 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. 1 ; Nr. 10, no. 1 (2013-01-23), S.315-325 |
| Datensatznummer |
250017474
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| Publikation (Nr.) |
 copernicus.org/bg-10-315-2013.pdf |
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| Zusammenfassung |
| The effect of ocean acidification on the balance between gross community
production (GCP) and community respiration (CR) (i.e., net community
production, NCP) of plankton communities was investigated in summer 2010 in
Kongsfjorden, west of Svalbard. Surface water, which was characterized by low
concentrations of dissolved inorganic nutrients and chlorophyll a (a proxy
of phytoplankton biomass), was enclosed in nine mesocosms and subjected to
eight pCO2 levels (two replicated controls and seven enhanced pCO2
treatments) for one month. Nutrients were added to all mesocosms on day 13 of
the experiment, and thereafter increase of chlorophyll a was provoked in
all mesocosms. No clear trend in response to increasing pCO2 was found
in the daily values of NCP, CR, and GCP. For further analysis, these
parameters were cumulated for the following three periods: phase 1 – end of
CO2 manipulation until nutrient addition (t4 to t13); phase 2 –
nutrient addition until the second chlorophyll a minimum (t14 to t21);
phase 3 – the second chlorophyll a minimum until the end of this study
(t22 to t28). A significant response was detected as a decrease of NCP
with increasing pCO2 during phase 3. CR was relatively stable
throughout the experiment in all mesocosms. As a result, the cumulative GCP
significantly decreased with increasing pCO2 during phase 3. After the
nutrient addition, the ratios of cumulative NCP to cumulative consumption of
NO3 and PO4 showed a significant decrease during phase 3 with
increasing pCO2. The results suggest that elevated pCO2
influenced cumulative NCP and stoichiometric C and nutrient coupling of the
plankton community in a high-latitude fjord only for a limited period.
However provided that there were some differences or weak correlations
between NCP data based on different methods in the same experiment, this
conclusion should be taken with caution. |
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