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| Titel |
Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments |
| VerfasserIn |
M.-C. Ciobanu, M. Rabineau, L. Droz, S. Révillon, J.-F. Ghiglione, B. Dennielou, S.-J. Jorry, J. Kallmeyer, J. Etoubleau, P. Pignet, P. Crassous, O. Vandenabeele-Trambouze, J. Laugier, M. Guégan, A. Godfroy, K. Alain |
| 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 ; 9, no. 9 ; Nr. 9, no. 9 (2012-09-03), S.3491-3512 |
| Datensatznummer |
250007284
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| Publikation (Nr.) |
 copernicus.org/bg-9-3491-2012.pdf |
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| Zusammenfassung |
| An interdisciplinary study was conducted to evaluate the relationship
between geological and paleoenvironmental parameters and the bacterial and
archaeal community structure of two contrasting subseafloor sites in the
Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both
depositional environments in this area are well-documented from
paleoclimatic and paleooceanographic point of views. Available data sets
allowed us to calibrate the investigated cores with reference and dated
cores previously collected in the same area, and notably correlated to
Quaternary climate variations. DNA-based fingerprints showed that the
archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion
sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and
Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both
sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within
Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were
Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various
substrates and cultivation conditions allowed us to isolate 75 strains
belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the
Betaproteobacteria group was consistently detected in the Ligurian Sea sediments,
characterized by a heterolithic facies with numerous turbidites from a
deep-sea levee. Analysis of relative betaproteobacterial abundances and
turbidite frequency suggested that the microbial diversity was a result of
main climatic changes occurring during the last 20 ka. Statistical direct
multivariate canonical correspondence analyses (CCA) showed that the
availability of electron acceptors and the quality of electron donors
(indicated by age) strongly influenced the community structure. In contrast,
within the Gulf of Lion core, characterized by a homogeneous lithological
structure of upper-slope environment, most detected groups were Bacteroidetes and, to a
lesser extent, Betaproteobacteria. At both site, the detection of Betaproteobacteria coincided with increased
terrestrial inputs, as confirmed by the geochemical measurements (Si, Sr, Ti
and Ca). In the Gulf of Lion, geochemical parameters were also found to
drive microbial community composition. Taken together, our data suggest that
the palaeoenvironmental history of erosion and deposition recorded in the
Western Mediterranean Sea sediments has left its imprint on the
sedimentological context for microbial habitability, and then indirectly on
structure and composition of the microbial communities during the late
Quaternary. |
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