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Long-term in situ permafrost thaw effects on bacterial communities and potential aerobic respiration

Author:
  • Sylvain Monteux
  • James T. Weedon
  • Gesche Blume-Werry
  • Konstantin Gavazov
  • Vincent E.J. Jassey
  • Margareta Johansson
  • Frida Keuper
  • Carolina Olid
  • Ellen Dorrepaal
Publishing year: 2018-09
Language: English
Pages: 2129-2141
Publication/Series: ISME Journal
Volume: 12
Issue: 9
Document type: Journal article
Publisher: Nature Publishing Group

Abstract english

The decomposition of large stocks of soil organic carbon in thawing permafrost might depend on more than climate change-induced temperature increases: indirect effects of thawing via altered bacterial community structure (BCS) or rooting patterns are largely unexplored. We used a 10-year in situ permafrost thaw experiment and aerobic incubations to investigate alterations in BCS and potential respiration at different depths, and the extent to which they are related with each other and with root density. Active layer and permafrost BCS strongly differed, and the BCS in formerly frozen soils (below the natural thawfront) converged under induced deep thaw to strongly resemble the active layer BCS, possibly as a result of colonization by overlying microorganisms. Overall, respiration rates decreased with depth and soils showed lower potential respiration when subjected to deeper thaw, which we attributed to gradual labile carbon pool depletion. Despite deeper rooting under induced deep thaw, root density measurements did not improve soil chemistry-based models of potential respiration. However, BCS explained an additional unique portion of variation in respiration, particularly when accounting for differences in organic matter content. Our results suggest that by measuring bacterial community composition, we can improve both our understanding and the modeling of the permafrost carbon feedback.

Keywords

  • Geosciences, Multidisciplinary

Other

Published
  • ISSN: 1751-7362
E-mail: margareta [dot] johansson [at] nateko [dot] lu [dot] se

Researcher

Dept of Physical Geography and Ecosystem Science

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Department of Physical Geography and Ecosystem Science
Lund University
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