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Biogeochemical plant–soil microbe feedback in response to climate warming in peatlands

Nature Climate Change volume 3, pages 273277 (2013) | Download Citation

Abstract

Peatlands act as global sinks of atmospheric carbon (C) through the accumulation of organic matter1, primarily made up of decay-resistant litter of peat mosses2. However, climate warming has been shown to promote vascular plant growth in peatlands, especially ericaceous shrubs3. A change in vegetation cover is in turn expected to modify above-ground/below-ground interactions4, but the biogeochemical mechanisms involved remain unknown. Here, by selecting peatlands at different altitudes to simulate a natural gradient of soil temperature, we show that the expansion of ericaceous shrubs with warming is associated with an increase of polyphenol content in both plant litter and pore water. In turn, this retards the release of nitrogen (N) from decomposing litter, increases the amount of dissolved organic N and reduces N immobilization by soil microbes. A decrease of soil water content with increasing temperature promotes the growth of fungi, which feeds back positively on ericaceous shrubs by facilitating the symbiotic acquisition of dissolved organic N. We also observed a higher release of labile C from vascular plant roots at higher soil temperatures, which promotes the microbial investment in C-degrading enzymes. Our data suggest that climate-induced changes in plant cover can reduce the productivity of peat mosses and potentially prime the decomposition of organic matter by affecting the stoichiometry of soil enzymatic activity.

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Acknowledgements

We thank M. Lamentovicz, E. A. D. Mitchell, T. Spiegelberger, E. Feldmeyer-Christe, P. Gomez, A. Margot, P. Iacumin, G. Cavallo, R. Marchesini, J. D. Teuscher, E. Rossel, K. Vernez and J. D. Welch for assistance. The Service des Forêts, de la Faune et de la Nature (Canton de Vaud) and the Service de la promotion de la nature—Office de l’agriculture et de la nature (Canton de Berne) are acknowledged for giving the permission to access the study peatlands. This study was financially supported by the Swiss National Science Foundation (project ClimaBog, grant 205321-129981 to L.B.).

Author information

Affiliations

  1. WSL Swiss Federal Institute for Forest, Snow and Landscape Research, Site Lausanne, Station 2, CH-1015 Lausanne, Switzerland

    • Luca Bragazza
    • , Julien Parisod
    •  & Alexandre Buttler
  2. École Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering (ENAC), Laboratory of Ecological Systems (ECOS), Station 2, CH-1015 Lausanne, Switzerland

    • Luca Bragazza
    • , Julien Parisod
    •  & Alexandre Buttler
  3. University of Ferrara, Department of Life Science and Biotechnologies, Corso Ercole I d’Este 32, I-44121 Ferrara, Italy

    • Luca Bragazza
  4. Laboratoire de Chrono-Environnement, UMR 6249 CNRS—INRA, Université de Franche-Comté, 25030 Besançon, France

    • Alexandre Buttler
  5. Soil and Ecosystem Ecology Laboratory, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK

    • Richard D. Bardgett

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Contributions

L.B. and A.B designed the study; L.B. carried out the research with assistance from J.P. and A.B.; L.B. analysed the data with contribution from all the authors; L.B. and R.D.B. wrote the paper with contribution from A.B. and J.P.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Luca Bragazza.

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DOI

https://doi.org/10.1038/nclimate1781

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