Maximum growth rates and possible life strategies of different bacterioplankton groups in relation to phosphorus availability in a freshwater reservoir

Authors

  • Karel Šimek,

    Corresponding author
    1. Biological Centre of the Academy of Sciences of the Czech Republic, Hydrobiological Institute, Na Sádkách 7, CZ-37005 České Budějovice, Czech Republic.
    2. Faculty of Biological Sciences, University of South Bohemia, CZ-37005 České Budějovice, Czech Republic.
      *E-mail ksimek@hbu.cas.cz; Tel. (+420) 38 7775873; Fax (+420) 38 5310248.
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  • Karel Horňák,

    1. Biological Centre of the Academy of Sciences of the Czech Republic, Hydrobiological Institute, Na Sádkách 7, CZ-37005 České Budějovice, Czech Republic.
    2. Faculty of Biological Sciences, University of South Bohemia, CZ-37005 České Budějovice, Czech Republic.
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  • Jan Jezbera,

    1. Biological Centre of the Academy of Sciences of the Czech Republic, Hydrobiological Institute, Na Sádkách 7, CZ-37005 České Budějovice, Czech Republic.
    2. Faculty of Biological Sciences, University of South Bohemia, CZ-37005 České Budějovice, Czech Republic.
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  • Jiří Nedoma,

    1. Biological Centre of the Academy of Sciences of the Czech Republic, Hydrobiological Institute, Na Sádkách 7, CZ-37005 České Budějovice, Czech Republic.
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  • Jaroslav Vrba,

    1. Biological Centre of the Academy of Sciences of the Czech Republic, Hydrobiological Institute, Na Sádkách 7, CZ-37005 České Budějovice, Czech Republic.
    2. Faculty of Biological Sciences, University of South Bohemia, CZ-37005 České Budějovice, Czech Republic.
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  • Viera Straškrábová,

    1. Biological Centre of the Academy of Sciences of the Czech Republic, Hydrobiological Institute, Na Sádkách 7, CZ-37005 České Budějovice, Czech Republic.
    2. Faculty of Biological Sciences, University of South Bohemia, CZ-37005 České Budějovice, Czech Republic.
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  • Miroslav Macek,

    1. Biological Centre of the Academy of Sciences of the Czech Republic, Hydrobiological Institute, Na Sádkách 7, CZ-37005 České Budějovice, Czech Republic.
    2. Universidad Nacional Autónoma de México, campus Iztacala, Av. de los Barrios 1, los Reyes Iztacala, Tlalnepantla, 54090 Edo. Mexico, Mexico.
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  • John R. Dolan,

    1. Marine Microbial Ecology Group, LOV, Univ Paris VI and CNRS UMR 7093, Station Zoologique, B.P. 28, 06230 Villefranche-sur-Mer, France.
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  • Martin W. Hahn

    1. Institute for Limnology, Austrian Academy of Sciences, Mondseestrasse 9, A-5310 Mondsee, Austria.
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*E-mail ksimek@hbu.cas.cz; Tel. (+420) 38 7775873; Fax (+420) 38 5310248.

Summary

We investigated net growth rates of distinct bacterioplankton groups and heterotrophic nanoflagellate (HNF) communities in relation to phosphorus availability by analysing eight in situ manipulation experiments, conducted between 1997 and 2003, in the canyon-shaped Římov reservoir (Czech Republic). Water samples were size-fractionated and incubated in dialysis bags at the sampling site or transplanted into an area of the reservoir, which differed in phosphorus limitation (range of soluble reactive phosphorus concentrations – SRP, 0.7–96 µg l−1). Using five different rRNA-targeted oligonucleotide probes, net growth rates of the probe-defined bacterial groups and HNF assemblages were estimated and related to SRP using Monod kinetics, yielding growth rate constants specific for each bacterial group. We found highly significant differences among their maximum growth rates while insignificant differences were detected in the saturation constants. However, the latter constants represent only tentative estimates mainly due to insufficient sensitivity of the method used at low in situ SRP concentrations. Interestingly, in these same experiments HNF assemblages grew significantly faster than any bacterial group studied except for a small, but abundant cluster of Betaproteobacteria (targeted by the R-BT065 probe). Potential ecological implications of different growth capabilities for possible life strategies of different bacterial phylogenetic lineages are discussed.

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