Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden

Northern peatlands in permafrost regions contain a large amount of organic carbon (C) in the soil. Climate warming and associated permafrost degradation are expected to have significant impacts on the C balance of these ecosystems, but the magnitude is uncertain. We incorporated a permafrost model,...

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Main Authors: J. Deng, C. Li, S. Frolking, Y. Zhang, K. Bäckstrand, P. Crill
Format: Article
Language:English
Published: Copernicus Publications 2014-09-01
Series:Biogeosciences
Online Access:http://www.biogeosciences.net/11/4753/2014/bg-11-4753-2014.pdf
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author J. Deng
C. Li
S. Frolking
Y. Zhang
K. Bäckstrand
P. Crill
author_facet J. Deng
C. Li
S. Frolking
Y. Zhang
K. Bäckstrand
P. Crill
author_sort J. Deng
collection DOAJ
description Northern peatlands in permafrost regions contain a large amount of organic carbon (C) in the soil. Climate warming and associated permafrost degradation are expected to have significant impacts on the C balance of these ecosystems, but the magnitude is uncertain. We incorporated a permafrost model, Northern Ecosystem Soil Temperature (NEST), into a biogeochemical model, DeNitrification-DeComposition (DNDC), to model C dynamics in high-latitude peatland ecosystems. The enhanced model was applied to assess effects of permafrost thaw on C fluxes of a subarctic peatland at Stordalen, Sweden. DNDC simulated soil freeze–thaw dynamics, net ecosystem exchange of CO<sub>2</sub> (NEE), and CH<sub>4</sub> fluxes across three typical land cover types, which represent a gradient in the process of ongoing permafrost thaw at Stordalen. Model results were compared with multiyear field measurements, and the validation indicates that DNDC was able to simulate observed differences in seasonal soil thaw, NEE, and CH<sub>4</sub> fluxes across the three land cover types. Consistent with the results from field studies, the modeled C fluxes across the permafrost thaw gradient demonstrate that permafrost thaw and the associated changes in soil hydrology and vegetation not only increase net uptake of C from the atmosphere but also increase the annual to decadal radiative forcing impacts on climate due to increased CH<sub>4</sub> emissions. This study indicates the potential of utilizing biogeochemical models, such as DNDC, to predict the soil thermal regime in permafrost areas and to investigate impacts of permafrost thaw on ecosystem C fluxes after incorporating a permafrost component into the model framework.
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spelling doaj.art-2b784ef89492417fb1ecde738314c50e2022-12-21T19:26:50ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-09-0111174753477010.5194/bg-11-4753-2014Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, SwedenJ. Deng0C. Li1S. Frolking2Y. Zhang3K. Bäckstrand4P. Crill5Earth Systems Research Center, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, 39 College Road, Durham NH 03824, USAEarth Systems Research Center, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, 39 College Road, Durham NH 03824, USAEarth Systems Research Center, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, 39 College Road, Durham NH 03824, USACanada Centre for Mapping and Earth Observation, Natural Resources Canada, 588 Booth Street, Ottawa ON K1A 0Y7, CanadaDepartment of Geological Sciences, Stockholm University, 106 91 Stockholm, SwedenDepartment of Geological Sciences, Stockholm University, 106 91 Stockholm, SwedenNorthern peatlands in permafrost regions contain a large amount of organic carbon (C) in the soil. Climate warming and associated permafrost degradation are expected to have significant impacts on the C balance of these ecosystems, but the magnitude is uncertain. We incorporated a permafrost model, Northern Ecosystem Soil Temperature (NEST), into a biogeochemical model, DeNitrification-DeComposition (DNDC), to model C dynamics in high-latitude peatland ecosystems. The enhanced model was applied to assess effects of permafrost thaw on C fluxes of a subarctic peatland at Stordalen, Sweden. DNDC simulated soil freeze–thaw dynamics, net ecosystem exchange of CO<sub>2</sub> (NEE), and CH<sub>4</sub> fluxes across three typical land cover types, which represent a gradient in the process of ongoing permafrost thaw at Stordalen. Model results were compared with multiyear field measurements, and the validation indicates that DNDC was able to simulate observed differences in seasonal soil thaw, NEE, and CH<sub>4</sub> fluxes across the three land cover types. Consistent with the results from field studies, the modeled C fluxes across the permafrost thaw gradient demonstrate that permafrost thaw and the associated changes in soil hydrology and vegetation not only increase net uptake of C from the atmosphere but also increase the annual to decadal radiative forcing impacts on climate due to increased CH<sub>4</sub> emissions. This study indicates the potential of utilizing biogeochemical models, such as DNDC, to predict the soil thermal regime in permafrost areas and to investigate impacts of permafrost thaw on ecosystem C fluxes after incorporating a permafrost component into the model framework.http://www.biogeosciences.net/11/4753/2014/bg-11-4753-2014.pdf
spellingShingle J. Deng
C. Li
S. Frolking
Y. Zhang
K. Bäckstrand
P. Crill
Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden
Biogeosciences
title Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden
title_full Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden
title_fullStr Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden
title_full_unstemmed Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden
title_short Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden
title_sort assessing effects of permafrost thaw on c fluxes based on multiyear modeling across a permafrost thaw gradient at stordalen sweden
url http://www.biogeosciences.net/11/4753/2014/bg-11-4753-2014.pdf
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