Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost
The release of greenhouse gases from the large organic carbon stock in permafrost deposits in the circumarctic regions may accelerate global warming upon thaw. The extent of this positive climate feedback is thought to be largely controlled by the microbial degradability of the organic matter preser...
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Online Access: | http://dx.doi.org/10.3389/feart.2021.737237 https://www.frontiersin.org/articles/10.3389/feart.2021.737237/full |
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crfrontiers:10.3389/feart.2021.737237 2024-09-15T18:29:54+00:00 Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost Melchert, Jan Olaf Wischhöfer, Philipp Knoblauch, Christian Eckhardt, Tim Liebner, Susanne Rethemeyer, Janet 2022 http://dx.doi.org/10.3389/feart.2021.737237 https://www.frontiersin.org/articles/10.3389/feart.2021.737237/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Earth Science volume 9 ISSN 2296-6463 journal-article 2022 crfrontiers https://doi.org/10.3389/feart.2021.737237 2024-08-13T04:04:51Z The release of greenhouse gases from the large organic carbon stock in permafrost deposits in the circumarctic regions may accelerate global warming upon thaw. The extent of this positive climate feedback is thought to be largely controlled by the microbial degradability of the organic matter preserved in these sediments. In addition, weathering and oxidation processes may release inorganic carbon preserved in permafrost sediments as CO 2 , which is generally not accounted for. We used 13 C and 14 C analysis and isotopic mass balances to differentiate and quantify organic and inorganic carbon released as CO 2 in the field from an active retrogressive thaw slump of Pleistocene-age Yedoma and during a 1.5-years incubation experiment. The results reveal that the dominant source of the CO 2 released from freshly thawed Yedoma exposed as thaw mound is Pleistocene-age organic matter (48–80%) and to a lesser extent modern organic substrate (3–34%). A significant portion of the CO 2 originated from inorganic carbon in the Yedoma (17–26%). The mixing of young, active layer material with Yedoma at a site on the slump floor led to the preferential mineralization of this young organic carbon source. Admixtures of younger organic substrates in the Yedoma thaw mound were small and thus rapidly consumed as shown by lower contributions to the CO 2 produced during few weeks of aerobic incubation at 4°C corresponding to approximately one thaw season. Future CO 2 fluxes from the freshly thawed Yedoma will contain higher proportions of ancient inorganic (22%) and organic carbon (61–78%) as suggested by the results at the end, after 1.5 years of incubation. The increasing contribution of inorganic carbon during the incubation is favored by the accumulation of organic acids from microbial organic matter degradation resulting in lower pH values and, in consequence, in inorganic carbon dissolution. Because part of the inorganic carbon pool is assumed to be of pedogenic origin, these emissions would ultimately not alter carbon budgets. ... Article in Journal/Newspaper permafrost Frontiers (Publisher) Frontiers in Earth Science 9 |
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The release of greenhouse gases from the large organic carbon stock in permafrost deposits in the circumarctic regions may accelerate global warming upon thaw. The extent of this positive climate feedback is thought to be largely controlled by the microbial degradability of the organic matter preserved in these sediments. In addition, weathering and oxidation processes may release inorganic carbon preserved in permafrost sediments as CO 2 , which is generally not accounted for. We used 13 C and 14 C analysis and isotopic mass balances to differentiate and quantify organic and inorganic carbon released as CO 2 in the field from an active retrogressive thaw slump of Pleistocene-age Yedoma and during a 1.5-years incubation experiment. The results reveal that the dominant source of the CO 2 released from freshly thawed Yedoma exposed as thaw mound is Pleistocene-age organic matter (48–80%) and to a lesser extent modern organic substrate (3–34%). A significant portion of the CO 2 originated from inorganic carbon in the Yedoma (17–26%). The mixing of young, active layer material with Yedoma at a site on the slump floor led to the preferential mineralization of this young organic carbon source. Admixtures of younger organic substrates in the Yedoma thaw mound were small and thus rapidly consumed as shown by lower contributions to the CO 2 produced during few weeks of aerobic incubation at 4°C corresponding to approximately one thaw season. Future CO 2 fluxes from the freshly thawed Yedoma will contain higher proportions of ancient inorganic (22%) and organic carbon (61–78%) as suggested by the results at the end, after 1.5 years of incubation. The increasing contribution of inorganic carbon during the incubation is favored by the accumulation of organic acids from microbial organic matter degradation resulting in lower pH values and, in consequence, in inorganic carbon dissolution. Because part of the inorganic carbon pool is assumed to be of pedogenic origin, these emissions would ultimately not alter carbon budgets. ... |
format |
Article in Journal/Newspaper |
author |
Melchert, Jan Olaf Wischhöfer, Philipp Knoblauch, Christian Eckhardt, Tim Liebner, Susanne Rethemeyer, Janet |
spellingShingle |
Melchert, Jan Olaf Wischhöfer, Philipp Knoblauch, Christian Eckhardt, Tim Liebner, Susanne Rethemeyer, Janet Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost |
author_facet |
Melchert, Jan Olaf Wischhöfer, Philipp Knoblauch, Christian Eckhardt, Tim Liebner, Susanne Rethemeyer, Janet |
author_sort |
Melchert, Jan Olaf |
title |
Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost |
title_short |
Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost |
title_full |
Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost |
title_fullStr |
Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost |
title_full_unstemmed |
Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost |
title_sort |
sources of co2 produced in freshly thawed pleistocene-age yedoma permafrost |
publisher |
Frontiers Media SA |
publishDate |
2022 |
url |
http://dx.doi.org/10.3389/feart.2021.737237 https://www.frontiersin.org/articles/10.3389/feart.2021.737237/full |
genre |
permafrost |
genre_facet |
permafrost |
op_source |
Frontiers in Earth Science volume 9 ISSN 2296-6463 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3389/feart.2021.737237 |
container_title |
Frontiers in Earth Science |
container_volume |
9 |
_version_ |
1810471387720056832 |