Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization
Rapid warming of Arctic ecosystems exposes soil organic matter (SOM) to accelerated microbial decomposition, potentially leading to increased emissions of carbon dioxide ( CO 2 ) and methane ( CH 4 ) that have a positive feedback on global warming. Current estimates of the magnitude and form of carb...
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ftcopernicus:oai:publications.copernicus.org:bg66528 2023-05-15T14:54:41+02:00 Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization Zheng, Jianqiu Thornton, Peter E. Painter, Scott L. Gu, Baohua Wullschleger, Stan D. Graham, David E. 2019-02-04 application/pdf https://doi.org/10.5194/bg-16-663-2019 https://www.biogeosciences.net/16/663/2019/ eng eng doi:10.5194/bg-16-663-2019 https://www.biogeosciences.net/16/663/2019/ eISSN: 1726-4189 Text 2019 ftcopernicus https://doi.org/10.5194/bg-16-663-2019 2019-12-24T09:49:29Z Rapid warming of Arctic ecosystems exposes soil organic matter (SOM) to accelerated microbial decomposition, potentially leading to increased emissions of carbon dioxide ( CO 2 ) and methane ( CH 4 ) that have a positive feedback on global warming. Current estimates of the magnitude and form of carbon emissions from Earth system models include significant uncertainties, partially due to the oversimplified representation of geochemical constraints on microbial decomposition. Here, we coupled modeling principles developed in different disciplines, including a thermodynamically based microbial growth model for methanogenesis and iron reduction, a pool-based model to represent upstream carbon transformations, and a humic ion-binding model for dynamic pH simulation to build a more versatile carbon decomposition model framework that can be applied to soils under varying redox conditions. This new model framework was parameterized and validated using synthesized anaerobic incubation data from permafrost-affected soils along a gradient of fine-scale thermal and hydrological variabilities across Arctic polygonal tundra. The model accurately simulated anaerobic CO 2 production and its temperature sensitivity using data on labile carbon pools and fermentation rates as model constraints. CH 4 production is strongly influenced by water content, pH, methanogen biomass, and presence of competing electron acceptors, resulting in high variability in its temperature sensitivity. This work provides new insights into the interactions of SOM pools, temperature increase, soil geochemical feedbacks, and resulting CO 2 and CH 4 production. The proposed anaerobic carbon decomposition framework presented here builds a mechanistic link between soil geochemistry and carbon mineralization, making it applicable over a wide range of soils under different environmental settings. Text Arctic Global warming permafrost Tundra Copernicus Publications: E-Journals Arctic Biogeosciences 16 3 663 680 |
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English |
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Rapid warming of Arctic ecosystems exposes soil organic matter (SOM) to accelerated microbial decomposition, potentially leading to increased emissions of carbon dioxide ( CO 2 ) and methane ( CH 4 ) that have a positive feedback on global warming. Current estimates of the magnitude and form of carbon emissions from Earth system models include significant uncertainties, partially due to the oversimplified representation of geochemical constraints on microbial decomposition. Here, we coupled modeling principles developed in different disciplines, including a thermodynamically based microbial growth model for methanogenesis and iron reduction, a pool-based model to represent upstream carbon transformations, and a humic ion-binding model for dynamic pH simulation to build a more versatile carbon decomposition model framework that can be applied to soils under varying redox conditions. This new model framework was parameterized and validated using synthesized anaerobic incubation data from permafrost-affected soils along a gradient of fine-scale thermal and hydrological variabilities across Arctic polygonal tundra. The model accurately simulated anaerobic CO 2 production and its temperature sensitivity using data on labile carbon pools and fermentation rates as model constraints. CH 4 production is strongly influenced by water content, pH, methanogen biomass, and presence of competing electron acceptors, resulting in high variability in its temperature sensitivity. This work provides new insights into the interactions of SOM pools, temperature increase, soil geochemical feedbacks, and resulting CO 2 and CH 4 production. The proposed anaerobic carbon decomposition framework presented here builds a mechanistic link between soil geochemistry and carbon mineralization, making it applicable over a wide range of soils under different environmental settings. |
format |
Text |
author |
Zheng, Jianqiu Thornton, Peter E. Painter, Scott L. Gu, Baohua Wullschleger, Stan D. Graham, David E. |
spellingShingle |
Zheng, Jianqiu Thornton, Peter E. Painter, Scott L. Gu, Baohua Wullschleger, Stan D. Graham, David E. Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization |
author_facet |
Zheng, Jianqiu Thornton, Peter E. Painter, Scott L. Gu, Baohua Wullschleger, Stan D. Graham, David E. |
author_sort |
Zheng, Jianqiu |
title |
Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization |
title_short |
Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization |
title_full |
Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization |
title_fullStr |
Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization |
title_full_unstemmed |
Modeling anaerobic soil organic carbon decomposition in Arctic polygon tundra: insights into soil geochemical influences on carbon mineralization |
title_sort |
modeling anaerobic soil organic carbon decomposition in arctic polygon tundra: insights into soil geochemical influences on carbon mineralization |
publishDate |
2019 |
url |
https://doi.org/10.5194/bg-16-663-2019 https://www.biogeosciences.net/16/663/2019/ |
geographic |
Arctic |
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Arctic |
genre |
Arctic Global warming permafrost Tundra |
genre_facet |
Arctic Global warming permafrost Tundra |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-16-663-2019 https://www.biogeosciences.net/16/663/2019/ |
op_doi |
https://doi.org/10.5194/bg-16-663-2019 |
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Biogeosciences |
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16 |
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663 |
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680 |
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1766326449680154624 |