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| Titel |
DNA from lake sediments reveals the long-term dynamics and diversity of Synechococcus assemblages |
| VerfasserIn |
I. Domaizon, O. Savichtcheva, D. Debroas, F. Arnaud, C. Villar, C. Pignol, B. Alric, M. E. Perga |
| 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. 6 ; Nr. 10, no. 6 (2013-06-14), S.3817-3838 |
| Datensatznummer |
250018286
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| Publikation (Nr.) |
 copernicus.org/bg-10-3817-2013.pdf |
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| Zusammenfassung |
| While picocyanobacteria (PC) are important actors in carbon and nutrient
cycles in aquatic systems, factors controlling their interannual dynamics
and diversity are poorly known due to the general lack of long-term
monitoring surveys. This study intended to fill this gap by applying a
DNA-based paleolimnological approach to sediment records from a deep
subalpine lake that has experienced dramatic changes in environmental
conditions during the last century (eutrophication, re-oligotrophication and
large-scale climate changes). In particular, we investigated the long-term
(100 yr) diversity and dynamics of Synechococcus,, PC that have presumably been affected
by both the lake trophic status changes and global warming.
The lake's morphological and environmental conditions provided the ideal
conditions for DNA preservation in the sediment archives. Generalised
additive models applied to quantitative PCR (qPCR; quantitative Polymerase Chain Reaction) results highlighted that
an increase in summer temperature could have a significant positive impact
on the relative abundance of Synechococcus, (fraction of Synechococcus, in total cyanobacteria).
The diversity of Synechococcus, in Lake Bourget was studied by phylogenetic analyses of
the 16S rRNA gene and the following internally transcribed spacer (ITS). Up
to 23 different OTUs (based on 16S rRNA), which fell into various
cosmopolitan or endemic clusters, were identified in samples from the past
100 yr. Moreover, the study of ITS revealed a higher diversity within the
major 16S rRNA-defined OTUs. Changes in PC diversity were related to the
lake's trophic status. Overall, qPCR and sequencing results showed that
environmental changes (in temperature and phosphorus concentration)
affected Synechococcus, community dynamics and structure, translating into changes in
genotype composition. These results also helped to re-evaluate the
geographical distribution of some Synechococcus, clusters.
Providing such novel insights into the long-term history of an important
group of primary producers, this study illustrates the promising approach
that consists in coupling molecular tools and paleolimnology to reconstruct
a lake's biodiversity history. |
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