Viruses in subarctic lakes and their impact on benthic and pelagic bacteria |
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Authors: | Christin Sä wströ m,Jenny Ask,& Jan Karlsson |
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Affiliation: | Department of Ecology and Environmental Science, Climate Impacts Research Centre (CIRC), UmeåUniversity, Abisko, Sweden;;Australian Rivers Institute, Griffith University, Nathan, Qld, Australia;;and Department of Ecology and Environmental Science, UmeåUniversity, Umeå, Sweden |
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Abstract: | Virus–bacterium interactions were investigated in the pelagic and benthic habitats in a set of lakes along an altitudinal gradient in the subarctic northern Sweden. Viral and bacterial abundances showed a significant variation between the lakes, with the highest benthic microbial abundances recorded in a high-altitude lake [993 m above sea level (a.s.l.)], whereas the highest pelagic microbial abundances were found in a low-altitude lake (270 m a.s.l.). In the pelagic habitat, there was also a distinct difference in microbial abundances between the summer–autumn and the winter sampling occasion. A positive relationship was noted between viruses and bacteria in both the pelagic and the benthic habitats. Visibly virus-infected bacterial cells were uncommon in the pelagic habitat and undetectable in the benthos. Both lytic and lysogenic pelagic viral production rates were undetectable or low; thus, a possible explanation for the relative high viral abundances found in the water column could be an allochthonous input of viruses or release of sediment-derived viruses. Overall, our results provide novel information about the relevance of viruses in the subarctic region and indicate that viruses play only a minor role in the nutrient and carbon cycling in the microbial communities of subarctic lakes. |
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Keywords: | subarctic bacteria virus benthic pelagic |
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