Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil
The fate of soil organic carbon (SOC) stored in the Arctic permafrost is a key concern as temperatures continue to rise in the northern hemisphere. Studies and conceptual models suggest that SOC degradation is affected by the composition of SOC, but it is unclear exactly what portions of SOC are vul...
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ftosti:oai:osti.gov:1235842 2023-07-30T04:01:24+02:00 Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil Yang, Ziming Wullschleger, Stan D. Liang, Liyuan Graham, David E. Gu, Baohua 2023-06-26 application/pdf http://www.osti.gov/servlets/purl/1235842 https://www.osti.gov/biblio/1235842 https://doi.org/10.1016/j.soilbio.2015.12.022 unknown http://www.osti.gov/servlets/purl/1235842 https://www.osti.gov/biblio/1235842 https://doi.org/10.1016/j.soilbio.2015.12.022 doi:10.1016/j.soilbio.2015.12.022 58 GEOSCIENCES 54 ENVIRONMENTAL SCIENCES 2023 ftosti https://doi.org/10.1016/j.soilbio.2015.12.022 2023-07-11T09:04:41Z The fate of soil organic carbon (SOC) stored in the Arctic permafrost is a key concern as temperatures continue to rise in the northern hemisphere. Studies and conceptual models suggest that SOC degradation is affected by the composition of SOC, but it is unclear exactly what portions of SOC are vulnerable to rapid breakdown and what mechanisms may be controlling SOC degradation upon permafrost thaw. Here, we examine the dynamic consumption and production of labile SOC in an anoxic incubation experiment using soil samples from the active layer at the Barrow Environmental Observatory, Barrow, Alaska, USA. Free-reducing sugars, alcohols, and low-molecular-weight (LMW) organic acids were analyzed during incubation at either –2 or 8 °C for up to 240 days. Results show that simple sugar and alcohol SOC largely account for the initial rapid release of CO 2 and CH 4 through anaerobic fermentation, whereas the fermentation products, acetate and formate, are subsequently utilized as primary substrates for methanogenesis. Iron(III) reduction is correlated to acetate production and methanogenesis, suggesting its important role as an electron acceptor in tundra SOC respiration. These observations are further supported in a glucose addition experiment, in which rapid CO 2 and CH 4 production occurred concurrently with rapid production and consumption of labile organics such as acetate. However, addition of tannic acid, as a more complex organic substrate, showed little influence on the overall production of CO 2 and CH 4 and organic acids. Together our study shows that LMW labile organics in SOC control the initial rapid release of green-house gases upon warming. We thus present a conceptual framework for the labile SOC transformations and their relations to fermentation, iron reduction and methanogenesis, thereby providing the basis for improved model prediction of climate feedbacks in the Arctic. Other/Unknown Material Arctic Barrow permafrost Tundra Alaska SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Arctic Soil Biology and Biochemistry 95 202 211 |
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Open Polar |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
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ftosti |
language |
unknown |
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58 GEOSCIENCES 54 ENVIRONMENTAL SCIENCES |
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58 GEOSCIENCES 54 ENVIRONMENTAL SCIENCES Yang, Ziming Wullschleger, Stan D. Liang, Liyuan Graham, David E. Gu, Baohua Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil |
topic_facet |
58 GEOSCIENCES 54 ENVIRONMENTAL SCIENCES |
description |
The fate of soil organic carbon (SOC) stored in the Arctic permafrost is a key concern as temperatures continue to rise in the northern hemisphere. Studies and conceptual models suggest that SOC degradation is affected by the composition of SOC, but it is unclear exactly what portions of SOC are vulnerable to rapid breakdown and what mechanisms may be controlling SOC degradation upon permafrost thaw. Here, we examine the dynamic consumption and production of labile SOC in an anoxic incubation experiment using soil samples from the active layer at the Barrow Environmental Observatory, Barrow, Alaska, USA. Free-reducing sugars, alcohols, and low-molecular-weight (LMW) organic acids were analyzed during incubation at either –2 or 8 °C for up to 240 days. Results show that simple sugar and alcohol SOC largely account for the initial rapid release of CO 2 and CH 4 through anaerobic fermentation, whereas the fermentation products, acetate and formate, are subsequently utilized as primary substrates for methanogenesis. Iron(III) reduction is correlated to acetate production and methanogenesis, suggesting its important role as an electron acceptor in tundra SOC respiration. These observations are further supported in a glucose addition experiment, in which rapid CO 2 and CH 4 production occurred concurrently with rapid production and consumption of labile organics such as acetate. However, addition of tannic acid, as a more complex organic substrate, showed little influence on the overall production of CO 2 and CH 4 and organic acids. Together our study shows that LMW labile organics in SOC control the initial rapid release of green-house gases upon warming. We thus present a conceptual framework for the labile SOC transformations and their relations to fermentation, iron reduction and methanogenesis, thereby providing the basis for improved model prediction of climate feedbacks in the Arctic. |
author |
Yang, Ziming Wullschleger, Stan D. Liang, Liyuan Graham, David E. Gu, Baohua |
author_facet |
Yang, Ziming Wullschleger, Stan D. Liang, Liyuan Graham, David E. Gu, Baohua |
author_sort |
Yang, Ziming |
title |
Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil |
title_short |
Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil |
title_full |
Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil |
title_fullStr |
Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil |
title_full_unstemmed |
Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil |
title_sort |
effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an arctic tundra soil |
publishDate |
2023 |
url |
http://www.osti.gov/servlets/purl/1235842 https://www.osti.gov/biblio/1235842 https://doi.org/10.1016/j.soilbio.2015.12.022 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Barrow permafrost Tundra Alaska |
genre_facet |
Arctic Barrow permafrost Tundra Alaska |
op_relation |
http://www.osti.gov/servlets/purl/1235842 https://www.osti.gov/biblio/1235842 https://doi.org/10.1016/j.soilbio.2015.12.022 doi:10.1016/j.soilbio.2015.12.022 |
op_doi |
https://doi.org/10.1016/j.soilbio.2015.12.022 |
container_title |
Soil Biology and Biochemistry |
container_volume |
95 |
container_start_page |
202 |
op_container_end_page |
211 |
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1772812147357646848 |