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Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study.
Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study.
- Source :
- Biogeosciences Discussions; 2012, Vol. 9 Issue 8, p10467-10511, 45p
- Publication Year :
- 2012
-
Abstract
- The effect of elevated seawater carbon dioxide (CO<subscript>2</subscript>) 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 pCO<subscript>2</subscript> range of 175-1085 µatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard). The bacterioplankton communities responded to rising chlorophyll a concentrations after a lag phase of only a few days with increasing protein production and extracellular enzyme activity and revealed a close coupling of heterotrophic bacterial activity to phytoplankton productivity in this experiment. The natural extracellular enzyme assemblages showed increased activity in response to moderate acidification. A decrease in seawater pH of 0.5 units roughly doubled rates of β-glucosidase and leucine-aminopeptidase. Activities of extracellular enzymes in the mesocosms were directly related to both seawater pH and primary production. Also primary production and bacterial protein production in the mesocosms at different pCO<subscript>2</subscript> were positively correlated. Therefore, it can be suggested that the effcient heterotrophic carbon utilization in this Arctic microbial food web had the potential to counteract increased phytoplankton production that was achieved under elevated pCO<subscript>2</subscript> in this study. However, our results also show that the transfer of beneficial pCO<subscript>2</subscript>-related effects on the cellular bacterial metabolism to the scale of community activity and organic matter degradation can be mitigated by the top-down control of bacterial abundances in natural microbial communities. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 18106277
- Volume :
- 9
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Biogeosciences Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 79922372
- Full Text :
- https://doi.org/10.5194/bgd-9-10467-2012