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| Titel |
Dynamics of auto- and heterotrophic picoplankton and associated viruses in Lake Geneva |
| VerfasserIn |
A. Parvathi, X. Zhong, A. S. Pradeep Ram, S. Jacquet |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 3 ; Nr. 18, no. 3 (2014-03-19), S.1073-1087 |
| Datensatznummer |
250120308
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| Publikation (Nr.) |
 copernicus.org/hess-18-1073-2014.pdf |
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| Zusammenfassung |
| Microbial dynamics have rarely been investigated in Lake Geneva, known as
the largest lake in western Europe. From a 5-month survey, we report dynamic
patterns of free-living virus, bacteria and small phytoplankton abundances
in response to a variety of environmental parameters. For the first time, we
fractionated the primary production to separate the contribution of
different size-related biological compartments and measured both bacterial
and viral production in addition to experiments conducted to quantify the
virus-induced bacterial mortality. We observed marked seasonal and vertical
variations in picocyanobacteria, bacteria and virus abundances and
production. The contribution of picoplankton and nanoplankton production to
the total primary production was high (reaching up to 76% of total
primary production) in November and the spring–summer transition period,
respectively. The impact of viral lysis on both bacteria and
picocyanobacteria was significantly higher than grazing activities.
Virus-induced picocyanobacterial mortality reached up to 66% of cell
removal compared to virus induced (heterotrophic) bacterial mortality, which
reached a maximum of 34% in July. Statistical analyzes revealed that
temperature and top-down control by viruses are among important factors
regulating the picocyanobacterial dynamics in this lake. More generally
speaking, our results add to the growing evidence and accepted view nowadays
that viruses are an important actor of freshwater microbial dynamics and
more globally of the functioning of the microbial food webs. |
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