Elevated temperature alters microbial communities, but not decomposition rates, during 3 years of in situ peat decomposition
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- Biosciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee, USA
- Environmental Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee, USA, Climate Change Science Institute, Oak Ridge National Laboratory , Oak Ridge, Tennessee, USA
- Northern Research Station, USDA Forest Service , Grand Rapids, Minnesota, USA
- Department of Geosciences, Boise State University , Boise, Idaho, USA
- Department of Earth, Ocean, and Atmospheric Science, Florida State University , Tallahassee, Florida, USA
- Biosciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee, USA, Climate Change Science Institute, Oak Ridge National Laboratory , Oak Ridge, Tennessee, USA, Department of Microbiology, University of Tennessee , Knoxville, Tennessee, USA
ABSTRACT Peatlands are large carbon sinks with primary production outpacing decomposition of organic matter. Results from the S pruce and P eatland R esponses U nder C hanging E nvironments (SPRUCE) study show net losses of organic matter and increased greenhouse gas production from peatlands in response to whole-ecosystem warming. Here, we investigated how warming and elevated CO 2 impact peat microbial communities and peat soil decomposition rates and characterized microbial communities through amplicon sequencing and compositional changes across four depth increments. Microbial diversity and community composition were significantly impacted by soil depth, temperature, and CO 2 treatment. Bacterial/archaeal α-diversity increased significantly with increasing temperature, and fungal α-diversity was lower under elevated CO 2 treatments. Trans domain microbial networks showed higher complexity of microbial communities in decomposition ladder depths from the warmed enclosures, and the number of highly connected hub taxa within the networks was positively correlated with temperature. Methanogenic hubs were identified in the networks constructed from the warmest enclosures, indicating increased importance of methanogenesis in response to warming. Microbial community responses were not however reflected in measures of peat soil decomposition, as warming and elevated CO 2 had no significant short-term effects on soil mass loss or composition. Regardless of treatment, on average only 4.5% of the original soil mass was lost after 3 years and variation between replicates was high, potentially masking treatment effects. Previous results at the SPRUCE experiment have shown warming is accelerating organic-matter decomposition and CO 2 and CH 4 production, and our results suggest these changes may be driven by warming-induced shifts in microbial communities. IMPORTANCE Microbial community changes in response to climate change drivers have the potential to alter the trajectory of important ecosystem functions. In this paper, we show that while microbial communities in peatland systems responded to manipulations of temperature and CO 2 concentrations, these changes were not associated with similar responses in peat decomposition rates over 3 years. It is unclear however from our current studies whether this functional resiliency over 3 years will continue over the longer time scales relevant to peatland ecosystem functions.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE; USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 2009006
- Journal Information:
- mSystems, Journal Name: mSystems Journal Issue: 5 Vol. 8; ISSN 2379-5077
- Publisher:
- American Society for MicrobiologyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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