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| Titel |
Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study |
| VerfasserIn |
J. Piontek, C. Borchard, M. Sperling, K. G. Schulz, U. Riebesell, A. Engel |
| 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 (2013-01-22), S.297-314 |
| Datensatznummer |
250017473
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| Publikation (Nr.) |
 copernicus.org/bg-10-297-2013.pdf |
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| Zusammenfassung |
The effect of elevated seawater carbon dioxide (CO2) on the activity of
a natural bacterioplankton community in an Arctic fjord system was
investigated by a mesocosm perturbation study in the frame of the European
Project on Ocean Acidification (EPOCA). A pCO2 range of
175–1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard).
The activity of natural extracellular enzyme assemblages increased in
response to acidification. Rates of β-glucosidase and
leucine-aminopeptidase increased along the gradient of mesocosm pCO2. A
decrease in seawater pH of 0.5 units almost doubled rates of both enzymes.
Heterotrophic bacterial activity was closely coupled to phytoplankton
productivity in this experiment. The bacterioplankton community responded to
rising chlorophyll a concentrations after a lag phase of only a few days with
increasing protein production and extracellular enzyme activity.
Time-integrated primary production and bacterial protein production were
positively correlated, strongly suggesting that higher amounts of
phytoplankton-derived organic matter were assimilated by heterotrophic
bacteria at increased primary production. Primary production increased under
high pCO2 in this study, and it can be suggested that the efficient
heterotrophic carbon utilisation had the potential to counteract the
enhanced autotrophic CO2 fixation. However, our results also show that
beneficial pCO2-related effects on bacterial activity can be mitigated
by the top-down control of bacterial abundances in natural microbial
communities. |
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