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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ftdoajarticles:oai:doaj.org/article:98c64c21c2534421bd0b9eb29bc1db26 2023-05-15T16:37:41+02:00 Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost Jan Olaf Melchert Philipp Wischhöfer Christian Knoblauch Tim Eckhardt Susanne Liebner Janet Rethemeyer 2022-01-01T00:00:00Z https://doi.org/10.3389/feart.2021.737237 https://doaj.org/article/98c64c21c2534421bd0b9eb29bc1db26 EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/feart.2021.737237/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.737237 https://doaj.org/article/98c64c21c2534421bd0b9eb29bc1db26 Frontiers in Earth Science, Vol 9 (2022) yedoma ice complex permafost carbon cycle climat change thermokarst radiocarbon Science Q article 2022 ftdoajarticles https://doi.org/10.3389/feart.2021.737237 2022-12-30T20:22:44Z 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 CO2, which is generally not accounted for. We used 13C and 14C analysis and isotopic mass balances to differentiate and quantify organic and inorganic carbon released as CO2 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 CO2 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 CO2 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 CO2 produced during few weeks of aerobic incubation at 4°C corresponding to approximately one thaw season. Future CO2 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. The ... Article in Journal/Newspaper Ice permafrost Thermokarst Directory of Open Access Journals: DOAJ Articles Frontiers in Earth Science 9 |
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language |
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topic |
yedoma ice complex permafost carbon cycle climat change thermokarst radiocarbon Science Q |
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yedoma ice complex permafost carbon cycle climat change thermokarst radiocarbon Science Q Jan Olaf Melchert Philipp Wischhöfer Christian Knoblauch Tim Eckhardt Susanne Liebner Janet Rethemeyer Sources of CO2 Produced in Freshly Thawed Pleistocene-Age Yedoma Permafrost |
topic_facet |
yedoma ice complex permafost carbon cycle climat change thermokarst radiocarbon Science Q |
description |
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 CO2, which is generally not accounted for. We used 13C and 14C analysis and isotopic mass balances to differentiate and quantify organic and inorganic carbon released as CO2 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 CO2 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 CO2 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 CO2 produced during few weeks of aerobic incubation at 4°C corresponding to approximately one thaw season. Future CO2 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. The ... |
format |
Article in Journal/Newspaper |
author |
Jan Olaf Melchert Philipp Wischhöfer Christian Knoblauch Tim Eckhardt Susanne Liebner Janet Rethemeyer |
author_facet |
Jan Olaf Melchert Philipp Wischhöfer Christian Knoblauch Tim Eckhardt Susanne Liebner Janet Rethemeyer |
author_sort |
Jan Olaf Melchert |
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 S.A. |
publishDate |
2022 |
url |
https://doi.org/10.3389/feart.2021.737237 https://doaj.org/article/98c64c21c2534421bd0b9eb29bc1db26 |
genre |
Ice permafrost Thermokarst |
genre_facet |
Ice permafrost Thermokarst |
op_source |
Frontiers in Earth Science, Vol 9 (2022) |
op_relation |
https://www.frontiersin.org/articles/10.3389/feart.2021.737237/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.737237 https://doaj.org/article/98c64c21c2534421bd0b9eb29bc1db26 |
op_doi |
https://doi.org/10.3389/feart.2021.737237 |
container_title |
Frontiers in Earth Science |
container_volume |
9 |
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1766027984323477504 |