Effect of elevated CO2 on the dynamics of particle-attached and free-living bacterioplankton communities in an Arctic fjord

Autor: S. Romac, U. Riebesell, J. I. Nissimov, L. Bittner, J. Gilbert, J. La Roche, A.-S. Roy, H. Schunck, A. Wichels, G. Gerdts, J. Piontek, M. Sperling, A. Engel
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: Biogeosciences, Vol 10, Iss 1, Pp 181-191 (2013)
Druh dokumentu: article
ISSN: 1726-4170
1726-4189
DOI: 10.5194/bg-10-181-2013
Popis: In the frame of the European Project on Ocean Acidification (EPOCA), the response of an Arctic pelagic community (pCO2 was investigated. For this purpose 9 large-scale in situ mesocosms were deployed in Kongsfjorden, Svalbard (78°56.2´ N, 11°53.6´ E), in 2010. The present study investigates effects on the communities of particle-attached (PA; >3 μm) and free-living (FL; < 3 μm > 0.2 μm) bacteria by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms, ranging from 185 to 1050 μatm initial pCO2, and the surrounding fjord. ARISA was able to resolve, on average, 27 bacterial band classes per sample and allowed for a detailed investigation of the explicit richness and diversity. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom, numbers of ARISA band classes in the PA community were reduced at low and medium CO2 (~ 185–685 μatm) by about 25%, while they were more or less stable at high CO2 (~ 820–1050 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in high CO2 mesocosms, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.
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