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Adding Stable Carbon Isotopes Improves Model Representation Of The Role Of Microbial Communities In Peatland Methane Cycling

Title: Adding Stable Carbon Isotopes Improves Model Representation Of The Role Of Microbial Communities In Peatland Methane Cycling.
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Name(s): Deng, Jia, author
McCalley, Carmody K., author
Frolking, Steve, author
Chanton, Jeff, author
Crill, Patrick, author
Varner, Ruth, author
Tyson, Gene, author
Rich, Virginia, author
Hines, Mark, author
Saleska, Scott R., author
Li, Changsheng, author
Type of Resource: text
Genre: Journal Article
Text
Journal Article
Date Issued: 2017-06
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Climate change is expected to have significant and uncertain impacts on methane (CH4) emissions from northern peatlands. Biogeochemical models can extrapolate site-specificCH(4) measurements to larger scales and predict responses of CH4 emissions to environmental changes. However, these models include considerable uncertainties and limitations in representing CH4 production, consumption, and transport processes. To improve predictions of CH4 transformations, we incorporated acetate and stable carbon (C) isotopic dynamics associated with CH4 cycling into a biogeochemistry model, DNDC. By including these new features, DNDC explicitly simulates acetate dynamics and the relative contribution of acetotrophic and hydro-genotrophic methanogenesis (AM and HM) to CH4 production, and predicts the C isotopic signature (delta C-13) in soil C pools and emitted gases. When tested against biogeochemical and microbial community observations at two sites in a zone of thawing permafrost in a subarctic peatland in Sweden, the new formulation substantially improved agreement with CH4 production pathways and delta C-13 in emitted CH4 (delta C-13-CH4), a measure of the integrated effects of microbial production and consumption, and of physical transport. We also investigated the sensitivity of simulated delta C-13-CH4 to C isotopic composition of substrates and, to fractionation factors for CH4 production (alpha(AM) and alpha(HM)), CH4 oxidation (alpha(MO)), and plant-mediated CH4 transport (alpha(TP)). The sensitivity analysis indicated that the delta C-13-CH4 is highly sensitive to the factors associated with microbial metabolism (alpha(AM), alpha(HM), and alpha(MO)). The model framework simulating stable C isotopic dynamics provides a robust basis for better constraining and testing microbial mechanisms in predicting CH4 cycling in peatlands.
Identifier: FSU_libsubv1_wos_000406239300036 (IID), 10.1002/2016MS000817 (DOI)
Keywords: climate-change, comparison project wetchimp, gas emissions, global wetland extent, integrated model, nitrous-oxide evolution, northern peatland, permafrost thaw, rainfall events, terrestrial ecosystems
Publication Note: The publisher's version of record is available at https://doi.org/10.1002/2016MS000817
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000406239300036
Host Institution: FSU
Is Part Of: Journal of Advances in Modeling Earth Systems.
1942-2466
Issue: iss. 2, vol. 9

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Deng, J., McCalley, C. K., Frolking, S., Chanton, J., Crill, P., Varner, R., … Li, C. (2017). Adding Stable Carbon Isotopes Improves Model Representation Of The Role Of Microbial Communities In Peatland Methane Cycling. Journal Of Advances In Modeling Earth Systems. Retrieved from http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000406239300036