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

Sperling, Martin, Piontek, Judith, Gerdts, G., Wichels, A., Schunck, Harald, Roy, Alexandra-Sophie, LaRoche, Julie, Gilbert, J., Bittner, L., Romac, S., Riebesell, Ulf and Engel, Anja (2013) Effect of elevated CO2 on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord. Open Access Biogeosciences (BG), 10 . pp. 181-191. DOI 10.5194/bg-10-181-2013.

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Abstract

The increase in atmospheric carbon dioxide (CO2) results in acidification of the oceans, expected to lead to the fastest drop in ocean pH in the last 300 million years, if anthropogenic emissions are continued at present rate. Due to higher solubility of gases in cold waters and increased exposure to the atmosphere by decreasing ice cover, the Arctic Ocean will be among the areas most strongly affected by ocean acidification. Yet, the response of the plankton community of high latitudes to ocean acidification has not been studied so far. This work is part of the Arctic campaign of the European Project on Ocean Acidification (EPOCA) in 2010, employing 9 in situ mesocosms of about 45 000 l each to simulate ocean acidification in Kongsfjorden, Svalbard (78°56.2' N 11°53.6' E). In the present study, we investigated effects of elevated CO2 on the composition and richness of particle attached (PA; >3 μm) and free living (FL; <3 μm >0.2 μm) bacterial communities by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms and the surrounding fjord, ranging from 185 to 1050 initial μatm pCO2. ARISA was able to resolve about 20–30 bacterial band-classes per sample and allowed for a detailed investigation of the explicit richness. 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 (phase 3 of the experiment), number of ARISA-band classes in the PA-community were reduced at low and medium CO2 (∼180–600 μatm) by about 25%, while it was more or less stable at high CO2 (∼ 650–800 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-treatments, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.

Document Type: Article
Funder compliance: info:eu-repo/grantAgreement/EC/FP7/211384
Keywords: Biogeochemistry: Environmental Microbiology
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
AWI
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-BI Biological Oceanography
Refereed: Yes
Open Access Journal?: Yes
DOI etc.: 10.5194/bg-10-181-2013
ISSN: 1726-4170
Projects: EPOCA, BioMarKs, Future Ocean
Expeditions/Models/Experiments:
Date Deposited: 26 Sep 2012 08:45
Last Modified: 23 May 2019 11:30
URI: http://oceanrep.geomar.de/id/eprint/15418

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