Carbon and nitrogen cycling in Yedoma permafrost controlled by microbial functional limitations

Sylvain Monteux*, Frida Keuper, Sébastien Fontaine, Konstantin Gavazov, Sara Hallin, Jaanis Juhanson, Eveline J. Krab, Sandrine Revaillot, Erik Verbruggen, Josefine Walz, James T. Weedon, Ellen Dorrepaal

*Corresponding author for this work

    Research output: Contribution to JournalArticleAcademicpeer-review

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    Abstract

    Warming-induced microbial decomposition of organic matter in permafrost soils constitutes a climate-change feedback of uncertain magnitude. While physicochemical constraints on soil functioning are relatively well understood, the constraints attributable to microbial community composition remain unclear. Here we show that biogeochemical processes in permafrost can be impaired by missing functions in the microbial community—functional limitations—probably due to environmental filtering of the microbial community over millennia-long freezing. We inoculated Yedoma permafrost with a functionally diverse exogenous microbial community to test this mechanism by introducing potentially missing microbial functions. This initiated nitrification activity and increased CO2 production by 38% over 161 days. The changes in soil functioning were strongly associated with an altered microbial community composition, rather than with changes in soil chemistry or microbial biomass. The present permafrost microbial community composition thus constrains carbon and nitrogen biogeochemical processes, but microbial colonization, likely to occur upon permafrost thaw in situ, can alleviate such functional limitations. Accounting for functional limitations and their alleviation could strongly increase our estimate of the vulnerability of permafrost soil organic matter to decomposition and the resulting global climate feedback.

    Original languageEnglish
    Pages (from-to)794-798
    Number of pages5
    JournalNature Geoscience
    Volume13
    Issue number12
    Early online date30 Nov 2020
    DOIs
    Publication statusPublished - Dec 2020

    Funding

    This study was funded by grants from the Wallenberg Academy Fellowship (KAW 2012.0152), Swedish Research Council (Dnr 621–2011–5444), Formas (Dnr 214–2011– 788) and Kempestiftelserna (JCK-1822) all awarded to E.D., by a grant from Formas (Dnr 2017–01182) awarded to E.J.K., by the European Union ClimMani COST Action (ES1308 COST ClimMani) Short Term Scientific Mission, by the Arctic Research Centre at Umeå University (Arcum) strategic funding grants awarded to S.M. and by the Department of Forest Mycology and Plant Pathology, SLU. We thank S. Lebeer and the ENdEMIC team for hosting part of the molecular work, T. H. Douglas from the US Army Cold Regions Research and Engineering Laboratory’s Permafrost Tunnel (Alaska) for assistance and permission to sample, and the staff of Abisko Scientific Research Station for hospitality and logistic support.

    FundersFunder number
    Arctic Research Centre at Umeå University
    Wallenberg AcademyKAW 2012.0152
    Saint Louis University
    Svenska Forskningsrådet FormasDnr 2017–01182, Dnr 214–2011– 788
    Knut och Alice Wallenbergs Stiftelse
    VetenskapsrådetDnr 621–2011–5444
    KempestiftelsernaJCK-1822

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