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

Monteux, Sylvain ; Weedon, James T. ; Blume-Werry, Gesche ; Gavazov, Konstantin ; Jassey, Vincent E.J. ; Johansson, Margareta LU ; Keuper, Frida ; Olid, Carolina and Dorrepaal, Ellen (2018) In ISME Journal 12(9). p.2129-2141
Abstract

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... (More)

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.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
ISME Journal
volume
12
issue
9
pages
2129 - 2141
publisher
Nature Publishing Group
external identifiers
  • pmid:29875436
  • scopus:85048074422
ISSN
1751-7362
DOI
10.1038/s41396-018-0176-z
language
English
LU publication?
yes
id
3d23bd22-6b2b-4e9e-8972-adab64801565
date added to LUP
2018-06-19 12:42:45
date last changed
2020-03-24 06:16:03
@article{3d23bd22-6b2b-4e9e-8972-adab64801565,
  abstract     = {<p>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.</p>},
  author       = {Monteux, Sylvain and Weedon, James T. and Blume-Werry, Gesche and Gavazov, Konstantin and Jassey, Vincent E.J. and Johansson, Margareta and Keuper, Frida and Olid, Carolina and Dorrepaal, Ellen},
  issn         = {1751-7362},
  language     = {eng},
  number       = {9},
  pages        = {2129--2141},
  publisher    = {Nature Publishing Group},
  series       = {ISME Journal},
  title        = {Long-term in situ permafrost thaw effects on bacterial communities and potential aerobic respiration},
  url          = {http://dx.doi.org/10.1038/s41396-018-0176-z},
  doi          = {10.1038/s41396-018-0176-z},
  volume       = {12},
  year         = {2018},
}