General Microbial Ecology

Distribution and Life Strategies of Two Bacterial Populations in a Eutrophic Lake

Markus G. Weinbauer, Manfred G. Höfle
DOI: 

Article Figures & Data

Figures

  • Fig. 1.
    Fig. 1.

    Abundance of the entire bacterial community and the populations of C. acidovorans PX54 and A. hydrophila PU7718 in three depth layers of Lake Plußsee on 23 September 1996. Data for the characterization of water stratification and total bacterial abundance are taken from reference38.

  • Fig. 2.
    Fig. 2.

    Bacterial abundance and production in size fractions of DOM. P/B ratio, production-to-biomass ratio. Data are presented as means (± ranges) of duplicate incubations.

  • Fig. 3.
    Fig. 3.

    Viral abundance and FVICs in size fractions of DOM. Data are presented as means (± ranges) of duplicate incubations.

  • Fig. 4.
    Fig. 4.

    Abundance of the populations of C. acidovorans PX54 and A. hydrophila PU7718 in size fractions of DOM. Data are presented as means (± ranges) of duplicate incubations.

  • Fig. 5.
    Fig. 5.

    Growth rate of the entire bacterial community and the populations of C. acidovorans PX54 and A. hydrophila PU7718 in size fractions of DOM. Growth rates were calculated as the slope of ln-transformed data of bacterial abundance versus time. Data are presented as means (± ranges) of duplicate incubations.

  • Fig. 6.
    Fig. 6.

    Comparison of the growth rates in the natural bacterial community determined by using bacterial abundance (BA) and bacterial production (BP). Solid line, relationship of 1:1.r 2 = 0.933.

  • Fig. 7.
    Fig. 7.

    Metabolic comparison and ecological similarity of the strains . C. acidovorans PX54 andA. hydrophila PU7718. BIOLOG and API ZYM test systems were used to assess metabolic versatilities of the two populations. Note that duplicates of BIOLOG plates and API ZYM strips showed the same results. Total, total substrates used; AA, amino acids; CHO, carbohydrates; FA, fatty acids. (A) Comparison of metabolic versatility of PX54 to that of PU7718, calculated as the ratio of the number of substrates used or enzymes expressed by PX54 to the number of substrates used or enzymes expressed by PU7718. (B) Metabolic similarity as determined by the NOI.

Tables

  • Table 1.

    DOC concentrations and viral abundances in the different DOM fractions at the start of the experiments

    FractionDOC (mg liter−1)aViral abundance (107 ml−1)b
    LMW DOM4.2 ± 0.140.1 ± 0.03
    Virus-reduced TDOM9.2 ± 0.150.6 ± 0.06
    Virus-rich TDOM9.6 ± 0.131.7 ± 0.20

    • ↵a Values are means (± standard deviations) of three samples.

    • ↵b Values are means (± ranges) calculated from two incubations.

  • Table 2.

    Some life strategy features of C. acidovorans PX54 and A. hydrophila PU7718

    TraitaMethodEvaluation of straine:
    PX54PU7718
    Growth rateDilution culture, mesocosmb LowHigh
    Effect of dilution on growth rateDilution cultureLowHigh
    Ability to utilize refractory DOMDilution cultureHighLow
    Nutritional rangeMetabolic fingerprintc LowHigh
    Range of expressed enzymesMetabolic fingerprintc LowHigh
    Resistance to predation-lysisDilution culture, chemostat,dmesocosmb HighLow

    • ↵a Traits were selected from reference5 and slightly modified.

    • ↵b Determined by Höfle (20).

    • ↵c Determined from BIOLOG and API ZYM tests.

    • ↵d Determined by Hahn and Höfle (19).

    • ↵e The evaluations of the traits of the two populations are given relative to one another.

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