The long-term biogeochemical fate of C in Subarctic thawing peat plateaus
Global warming causes permafrost to thaw at an unprecedented rate. In Northern Scandinavia, permafrost peat plateaus have been found to decline rapidly during the last decades, releasing old organic carbon to decomposition and runoff. Thawing peat plateaus can partly turn into thermokarst ponds, wit...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/542700 2023-08-20T04:08:45+02:00 The long-term biogeochemical fate of C in Subarctic thawing peat plateaus Kjær, Sigrid Trier id_orcid:0 000-0002-2810-9353 Nedkvitne, Nora Westermann, Sebastian Dörsch, Peter 2022 application/application/pdf https://hdl.handle.net/20.500.11850/542700 https://doi.org/10.3929/ethz-b-000542700 en eng Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/egusphere-egu22-5257 http://hdl.handle.net/20.500.11850/542700 doi:10.3929/ethz-b-000542700 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International EGUsphere info:eu-repo/semantics/conferenceObject info:eu-repo/semantics/publishedVersion 2022 ftethz https://doi.org/20.500.11850/54270010.3929/ethz-b-00054270010.5194/egusphere-egu22-5257 2023-07-30T23:54:37Z Global warming causes permafrost to thaw at an unprecedented rate. In Northern Scandinavia, permafrost peat plateaus have been found to decline rapidly during the last decades, releasing old organic carbon to decomposition and runoff. Thawing peat plateaus can partly turn into thermokarst ponds, with consequences for the biogeochemical fate of the released carbon. We investigated carbon degradation of thawing permafrost peat by incubating permafrost peat and thermokarst sediments from three peat plateaus in Northern Norway. The samples were incubated field moist at 10oC for almost one year. Initial decomposition was dominated by CO2 production which strongly responded to oxygen availability, while methane (CH4) production was small. Methane production increased drastically after more than ten months, indicating that thawed permafrost peat has a considerable potential to produce CH4 after a time lag. The cumulative CH4 production of thawed permafrost peat after one year of incubation exceeded that of overlaying active layer peat by up to 641 times, illustrating the potential of thawing subarctic permafrost to act as an additional CH4 source. Comparing laboratory thawed permafrost peat to thermokarst peat revealed remarkable differences in CH4 production, with much higher CH4 production potentials in thermokarst sediments during the first months of incubation and in some samples exceeding CH4 production measured in permafrost peat after one year. This suggests that the potential to produce CH4 increases dramatically with thermokarst formation. Interestingly, thawed permafrost peat produced more DOC over the period of one year than gaseous C (CO2 and CH4), which suggests that hydrological conditions are key to the understanding of the fate of C released from thawing peat plateaus. Conference Object Northern Norway Peat permafrost Subarctic Thermokarst ETH Zürich Research Collection Norway |
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Open Polar |
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ETH Zürich Research Collection |
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ftethz |
language |
English |
description |
Global warming causes permafrost to thaw at an unprecedented rate. In Northern Scandinavia, permafrost peat plateaus have been found to decline rapidly during the last decades, releasing old organic carbon to decomposition and runoff. Thawing peat plateaus can partly turn into thermokarst ponds, with consequences for the biogeochemical fate of the released carbon. We investigated carbon degradation of thawing permafrost peat by incubating permafrost peat and thermokarst sediments from three peat plateaus in Northern Norway. The samples were incubated field moist at 10oC for almost one year. Initial decomposition was dominated by CO2 production which strongly responded to oxygen availability, while methane (CH4) production was small. Methane production increased drastically after more than ten months, indicating that thawed permafrost peat has a considerable potential to produce CH4 after a time lag. The cumulative CH4 production of thawed permafrost peat after one year of incubation exceeded that of overlaying active layer peat by up to 641 times, illustrating the potential of thawing subarctic permafrost to act as an additional CH4 source. Comparing laboratory thawed permafrost peat to thermokarst peat revealed remarkable differences in CH4 production, with much higher CH4 production potentials in thermokarst sediments during the first months of incubation and in some samples exceeding CH4 production measured in permafrost peat after one year. This suggests that the potential to produce CH4 increases dramatically with thermokarst formation. Interestingly, thawed permafrost peat produced more DOC over the period of one year than gaseous C (CO2 and CH4), which suggests that hydrological conditions are key to the understanding of the fate of C released from thawing peat plateaus. |
format |
Conference Object |
author |
Kjær, Sigrid Trier id_orcid:0 000-0002-2810-9353 Nedkvitne, Nora Westermann, Sebastian Dörsch, Peter |
spellingShingle |
Kjær, Sigrid Trier id_orcid:0 000-0002-2810-9353 Nedkvitne, Nora Westermann, Sebastian Dörsch, Peter The long-term biogeochemical fate of C in Subarctic thawing peat plateaus |
author_facet |
Kjær, Sigrid Trier id_orcid:0 000-0002-2810-9353 Nedkvitne, Nora Westermann, Sebastian Dörsch, Peter |
author_sort |
Kjær, Sigrid Trier |
title |
The long-term biogeochemical fate of C in Subarctic thawing peat plateaus |
title_short |
The long-term biogeochemical fate of C in Subarctic thawing peat plateaus |
title_full |
The long-term biogeochemical fate of C in Subarctic thawing peat plateaus |
title_fullStr |
The long-term biogeochemical fate of C in Subarctic thawing peat plateaus |
title_full_unstemmed |
The long-term biogeochemical fate of C in Subarctic thawing peat plateaus |
title_sort |
long-term biogeochemical fate of c in subarctic thawing peat plateaus |
publisher |
Copernicus |
publishDate |
2022 |
url |
https://hdl.handle.net/20.500.11850/542700 https://doi.org/10.3929/ethz-b-000542700 |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Northern Norway Peat permafrost Subarctic Thermokarst |
genre_facet |
Northern Norway Peat permafrost Subarctic Thermokarst |
op_source |
EGUsphere |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/egusphere-egu22-5257 http://hdl.handle.net/20.500.11850/542700 doi:10.3929/ethz-b-000542700 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International |
op_doi |
https://doi.org/20.500.11850/54270010.3929/ethz-b-00054270010.5194/egusphere-egu22-5257 |
_version_ |
1774721219694690304 |