Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production
Carbon release due to permafrost thaw represents a potentially major positive climate change feedback. The magnitude of carbon loss and the proportion lost as methane (CH 4 ) vs. carbon dioxide (CO 2 ) depend on factors including temperature, mobilization of previously frozen carbon, hydrology, and...
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Online Access: | http://www.osti.gov/servlets/purl/1602275 https://www.osti.gov/biblio/1602275 https://doi.org/10.1073/pnas.1314641111 |
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ftosti:oai:osti.gov:1602275 2023-07-30T04:05:52+02:00 Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production Hodgkins, Suzanne B. Tfaily, Malak M. McCalley, Carmody K. Logan, Tyler A. Crill, Patrick M. Saleska, Scott R. Rich, Virginia I. Chanton, Jeffrey P. 2023-06-30 application/pdf http://www.osti.gov/servlets/purl/1602275 https://www.osti.gov/biblio/1602275 https://doi.org/10.1073/pnas.1314641111 unknown http://www.osti.gov/servlets/purl/1602275 https://www.osti.gov/biblio/1602275 https://doi.org/10.1073/pnas.1314641111 doi:10.1073/pnas.1314641111 54 ENVIRONMENTAL SCIENCES 2023 ftosti https://doi.org/10.1073/pnas.1314641111 2023-07-11T09:40:15Z Carbon release due to permafrost thaw represents a potentially major positive climate change feedback. The magnitude of carbon loss and the proportion lost as methane (CH 4 ) vs. carbon dioxide (CO 2 ) depend on factors including temperature, mobilization of previously frozen carbon, hydrology, and changes in organic matter chemistry associated with environmental responses to thaw. While the first three of these effects are relatively well understood, the effect of organic matter chemistry remains largely unstudied. To address this gap, we examined the biogeochemistry of peat and dissolved organic matter (DOM) along a ~40-y permafrost thaw progression from recently- to fully thawed sites in Stordalen Mire (68.35°N, 19.05°E), a thawing peat plateau in northern Sweden. Thaw-induced subsidence and the resulting inundation along this progression led to succession in vegetation types accompanied by an evolution in organic matter chemistry. Peat C/N ratios decreased whereas humification rates increased, and DOM shifted toward lower molecular weight compounds with lower aromaticity, lower organic oxygen content, and more abundant microbially produced compounds. Corresponding changes in decomposition along this gradient included increasing CH 4 and CO 2 production potentials, higher relative CH 4 /CO 2 ratios, and a shift in CH 4 production pathway from CO 2 reduction to acetate cleavage. These results imply that subsidence and thermokarst-associated increases in organic matter lability cause shifts in biogeochemical processes toward faster decomposition with an increasing proportion of carbon released as CH 4 . This impact of permafrost thaw on organic matter chemistry could intensify the predicted climate feedbacks of increasing temperatures, permafrost carbon mobilization, and hydrologic changes. Other/Unknown Material Northern Sweden Peat Peat plateau permafrost Thermokarst SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Stordalen ENVELOPE(7.337,7.337,62.510,62.510) Proceedings of the National Academy of Sciences 111 16 5819 5824 |
institution |
Open Polar |
collection |
SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
op_collection_id |
ftosti |
language |
unknown |
topic |
54 ENVIRONMENTAL SCIENCES |
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54 ENVIRONMENTAL SCIENCES Hodgkins, Suzanne B. Tfaily, Malak M. McCalley, Carmody K. Logan, Tyler A. Crill, Patrick M. Saleska, Scott R. Rich, Virginia I. Chanton, Jeffrey P. Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
Carbon release due to permafrost thaw represents a potentially major positive climate change feedback. The magnitude of carbon loss and the proportion lost as methane (CH 4 ) vs. carbon dioxide (CO 2 ) depend on factors including temperature, mobilization of previously frozen carbon, hydrology, and changes in organic matter chemistry associated with environmental responses to thaw. While the first three of these effects are relatively well understood, the effect of organic matter chemistry remains largely unstudied. To address this gap, we examined the biogeochemistry of peat and dissolved organic matter (DOM) along a ~40-y permafrost thaw progression from recently- to fully thawed sites in Stordalen Mire (68.35°N, 19.05°E), a thawing peat plateau in northern Sweden. Thaw-induced subsidence and the resulting inundation along this progression led to succession in vegetation types accompanied by an evolution in organic matter chemistry. Peat C/N ratios decreased whereas humification rates increased, and DOM shifted toward lower molecular weight compounds with lower aromaticity, lower organic oxygen content, and more abundant microbially produced compounds. Corresponding changes in decomposition along this gradient included increasing CH 4 and CO 2 production potentials, higher relative CH 4 /CO 2 ratios, and a shift in CH 4 production pathway from CO 2 reduction to acetate cleavage. These results imply that subsidence and thermokarst-associated increases in organic matter lability cause shifts in biogeochemical processes toward faster decomposition with an increasing proportion of carbon released as CH 4 . This impact of permafrost thaw on organic matter chemistry could intensify the predicted climate feedbacks of increasing temperatures, permafrost carbon mobilization, and hydrologic changes. |
author |
Hodgkins, Suzanne B. Tfaily, Malak M. McCalley, Carmody K. Logan, Tyler A. Crill, Patrick M. Saleska, Scott R. Rich, Virginia I. Chanton, Jeffrey P. |
author_facet |
Hodgkins, Suzanne B. Tfaily, Malak M. McCalley, Carmody K. Logan, Tyler A. Crill, Patrick M. Saleska, Scott R. Rich, Virginia I. Chanton, Jeffrey P. |
author_sort |
Hodgkins, Suzanne B. |
title |
Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production |
title_short |
Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production |
title_full |
Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production |
title_fullStr |
Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production |
title_full_unstemmed |
Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production |
title_sort |
changes in peat chemistry associated with permafrost thaw increase greenhouse gas production |
publishDate |
2023 |
url |
http://www.osti.gov/servlets/purl/1602275 https://www.osti.gov/biblio/1602275 https://doi.org/10.1073/pnas.1314641111 |
long_lat |
ENVELOPE(7.337,7.337,62.510,62.510) |
geographic |
Stordalen |
geographic_facet |
Stordalen |
genre |
Northern Sweden Peat Peat plateau permafrost Thermokarst |
genre_facet |
Northern Sweden Peat Peat plateau permafrost Thermokarst |
op_relation |
http://www.osti.gov/servlets/purl/1602275 https://www.osti.gov/biblio/1602275 https://doi.org/10.1073/pnas.1314641111 doi:10.1073/pnas.1314641111 |
op_doi |
https://doi.org/10.1073/pnas.1314641111 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
111 |
container_issue |
16 |
container_start_page |
5819 |
op_container_end_page |
5824 |
_version_ |
1772818170890944512 |