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| Titel |
Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic) |
| VerfasserIn |
E. Ortega-Retuerta, F. Joux, W. H. Jeffrey, J. F. Ghiglione |
| 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. 4 ; Nr. 10, no. 4 (2013-04-25), S.2747-2759 |
| Datensatznummer |
250018218
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| Publikation (Nr.) |
 copernicus.org/bg-10-2747-2013.pdf |
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| Zusammenfassung |
| We 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. |
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