Mapping field-scale spatial patterns of size and activity of the denitrifier community

Authors

  • Laurent Philippot,

    Corresponding author
    1. INRA, UMR 1229, F-21000 Dijon, France.
    2. University of Burgundy, UMR 1229, F-21000 Dijon, France.
      *E-mail Laurent.Philippot@dijon.inra.fr; Tel. (+33) 3 80 69 33 46; Fax (+33) 3 80 69 32 24.
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  • Jiri Čuhel,

    1. Biology Centre, Institute of Soil Biology and University of South Bohemia – Faculty of Science, Na Sádkách 7, 370 05 České Budìjovice, Czech Republic.
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  • Nicolas P.A. Saby,

    1. INRA, Centre de Recherche d'Orléans, US 1106, INFOSOL Unit, BP 20619 Ardon – 45166, Olivet Cedex, France.
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  • Dominique Chèneby,

    1. INRA, UMR 1229, F-21000 Dijon, France.
    2. University of Burgundy, UMR 1229, F-21000 Dijon, France.
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  • Alicia Chroňáková,

    1. Biology Centre, Institute of Soil Biology and University of South Bohemia – Faculty of Science, Na Sádkách 7, 370 05 České Budìjovice, Czech Republic.
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  • David Bru,

    1. INRA, UMR 1229, F-21000 Dijon, France.
    2. University of Burgundy, UMR 1229, F-21000 Dijon, France.
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  • Dominique Arrouays,

    1. INRA, Centre de Recherche d'Orléans, US 1106, INFOSOL Unit, BP 20619 Ardon – 45166, Olivet Cedex, France.
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  • Fabrice Martin-Laurent,

    1. INRA, UMR 1229, F-21000 Dijon, France.
    2. University of Burgundy, UMR 1229, F-21000 Dijon, France.
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  • Miloslav Šimek

    1. Biology Centre, Institute of Soil Biology and University of South Bohemia – Faculty of Science, Na Sádkách 7, 370 05 České Budìjovice, Czech Republic.
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*E-mail Laurent.Philippot@dijon.inra.fr; Tel. (+33) 3 80 69 33 46; Fax (+33) 3 80 69 32 24.

Summary

There is ample evidence that microbial processes can exhibit large variations in activity on a field scale. However, very little is known about the spatial distribution of the microbial communities mediating these processes. Here we used geostatistical modelling to explore spatial patterns of size and activity of the denitrifying community, a functional guild involved in N-cycling, in a grassland field subjected to different cattle grazing regimes. We observed a non-random distribution pattern of the size of the denitrifier community estimated by quantification of the denitrification genes copy numbers with a macro-scale spatial dependence (6–16 m) and mapped the distribution of this functional guild in the field. The spatial patterns of soil properties, which were strongly affected by presence of cattle, imposed significant control on potential denitrification activity, potential N2O production and relative abundance of some denitrification genes but not on the size of the denitrifier community. Absolute abundance of most denitrification genes was not correlated with the distribution patterns of potential denitrification activity or potential N2O production. However, the relative abundance of bacteria possessing the nosZ gene encoding the N2O reductase in the total bacterial community was a strong predictor of the N2O/(N2 + N2O) ratio, which provides evidence for a relationship between bacterial community composition based on the relative abundance of denitrifiers in the total bacterial community and ecosystem processes. More generally, the presented geostatistical approach allows integrated mapping of microbial communities, and hence can facilitate our understanding of relationships between the ecology of microbial communities and microbial processes along environmental gradients.

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