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Microbial community dynamics in a humic lake: differential persistence of common freshwater phylotypes

Authors

  • Ryan J. Newton,

    1. Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, USA.
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  • Angela D. Kent,

    1. Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
    2. Center for Limnology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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    • Present address: Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.

  • Eric W. Triplett,

    1. Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611-0700, USA.
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  • Katherine D. McMahon

    Corresponding author
    1. Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, USA.
    2. Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
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*E-mail tmcmahon@engr.wisc.edu; Tel. (+1) 608 263 3137; Fax (+1) 608 262 5199.

Summary

In an effort to better understand the factors contributing to patterns in freshwater bacterioplankton community composition and diversity, we coupled automated ribosomal intergenic spacer analysis (ARISA) to analysis of 16S ribosomal RNA (rRNA) gene sequences to follow the persistence patterns of 46 individual phylotypes over 3 years in Crystal Bog Lake. Additionally, we sought to identify linkages between the observed phylotype variations and known chemical and biological drivers. Sequencing of 16S rRNA genes obtained from the water column indicated the presence of phylotypes associated with the Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, TM7 and Verrucomicrobia phyla, as well as phylotypes with unknown affiliation. Employment of the 16S rRNA gene/ARISA method revealed that specific phylotypes varied independently of the entire bacterial community dynamics. Actinobacteria, which were present on greater than 95% of sampling dates, did not share the large temporal variability of the other identified phyla. Examination of phylotype relative abundance patterns (inferred using ARISA fragment relative fluorescence) revealed a strong correlation between the dominant phytoplankton succession and the relative abundance patterns of the majority of individual phylotypes. Further analysis revealed covariation among unique phylotypes, which formed several distinct bacterial assemblages correlated with particular phytoplankton communities. These data indicate the existence of unique persistence patterns for different common freshwater phylotypes, which may be linked to the presence of dominant phytoplankton species.

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