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Título

Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic)

AutorOrtega-Retuerta, E. ; Joux, F.; Jeffrey, W.H.; Ghiglione, J. F.
Fecha de publicación25-abr-2013
EditorEuropean Geosciences Union
CitaciónBiogeosciences 10: 2747-2759 (2013)
ResumenWe explored the patterns of total and active bacterial community structure in a gradient covering surface waters from the Mackenzie River to the coastal Beaufort Sea in the Canadian Arctic Ocean, with a particular focus on free-living (FL) vs. particle-attached (PA) communities. Capillary electrophoresis-single-strand conformation polymorphism (CE-SSCP) showed significant differences when comparing river, coast and open sea bacterial community structures. In contrast to the river and coastal waters, total (16S rDNA-based) and active (16S rRNA-based) communities in the open sea samples were not significantly different, suggesting that most present bacterial groups were equally active in this area. Additionally, we observed significant differences between PA and FL bacterial community structure in the open sea, but similar structure in the two fractions for coastal and river samples. Direct multivariate statistical analyses showed that total community structure was mainly driven by salinity (a proxy of dissolved organic carbon and chromophoric dissolved organic matter), suspended particles, amino acids and chlorophyll a. Pyrosequencing of 16S rRNA genes from selected samples confirmed significant differences between river, coastal and sea samples. The PA fraction was only different (15.7 % similarity) from the FL one in the open sea sample. Furthermore, PA samples generally showed higher diversity (Shannon, Simpson and Chao indices) than FL samples. At the class level, Opitutae was most abundant in the PA fraction of the sea sample, followed by Flavobacteria and Gammaproteobacteria, while the FL sea sample was dominated by Alphaproteobacteria. Finally, for the coast and river samples and both PA and FL fractions, Betaproteobacteria, Alphaproteobacteria and Actinobacteria were dominant. These results highlight the coexistence of particle specialists and generalists and the role of particle quality in structuring bacterial communities in the area. These results may also serve as a basis to predict further changes in bacterial communities should climate change lead to further increases in river discharge and related particle loads. © Author(s) 2013
DescripciónSpecial issue How changes in ice cover, permafrost and UV radiation impact on biodiversity and biogeochemical fluxes in the Arctic Ocean – The Malina project.-- 13 pages, 6 figures, 4 tables, supplementary material related to this article is available online at: http://www.biogeosciences.net/10/2747/2013/bg-10-2747-2013-supplement.pdf
Versión del editorhttp://dx.doi.org/10.5194/bg-10-2747-2013
URIhttp://hdl.handle.net/10261/115546
DOI10.5194/bg-10-2747-2013
Identificadoresdoi: 10.5194/bg-10-2747-2013
issn: 1726-4170
e-issn: 1726-4189
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