Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia
Permafrost ground is one of the largest repositories of stored terrestrial natural carbon and might become a carbon source with ongoing global warming. In particular, syngenetically frozen ice-rich Yedoma deposits originating from the late Pleistocene store a large amount of carbon. This carbon has...
Main Authors: | , , , , , , , , , |
---|---|
Format: | Other/Unknown Material |
Language: | English |
Published: |
2020
|
Subjects: | |
Online Access: | https://doi.org/10.5194/bg-2019-470 https://www.biogeosciences-discuss.net/bg-2019-470/ |
id |
ftcopernicus:oai:publications.copernicus.org:bgd82092 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:bgd82092 2023-05-15T16:37:17+02:00 Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia Windirsch, Torben Grosse, Guido Ulrich, Mathias Schirrmeister, Lutz Fedorov, Alexander N. Konstantinov, Pavel Ya. Fuchs, Matthias Jongejans, Loeka L. Wolter, Juliane Strauss, Jens 2020-01-03 info:eu-repo/semantics/application/pdf https://doi.org/10.5194/bg-2019-470 https://www.biogeosciences-discuss.net/bg-2019-470/ eng eng info:eu-repo/grantAgreement/EC/FP7/338335 doi:10.5194/bg-2019-470 https://www.biogeosciences-discuss.net/bg-2019-470/ info:eu-repo/semantics/openAccess eISSN: 1726-4189 info:eu-repo/semantics/Text 2020 ftcopernicus https://doi.org/10.5194/bg-2019-470 2020-01-06T15:41:59Z Permafrost ground is one of the largest repositories of stored terrestrial natural carbon and might become a carbon source with ongoing global warming. In particular, syngenetically frozen ice-rich Yedoma deposits originating from the late Pleistocene store a large amount of carbon. This carbon has not yet become part of the recent carbon cycle. With this study of Yedoma and associated Alas deposits in Central Yakutia we aim to understand the local sediment genesis and its effect on permafrost carbon storage. For this purpose, we investigated the Yukechi Alas area (61.76495° N, 130.46664° E), a thermokarst landscape degrading into Yedoma in Central Yakutia. Two sediment cores (Yedoma upland, 22.35 m depth, and Alas basin, 19.80 m depth) were drilled in 2015. We analyzed for ice content, total carbon and total nitrogen content, total organic carbon content, stable oxygen and hydrogen isotopes, stable carbon isotopes, mass specific magnetic susceptibility, grain size distribution, and radiocarbon ages. Samples taken from both cores were radiocarbon-dated up to 50,000 years before present. The laboratory analyses of both cores revealed very low carbon contents down to several meters depth. Those core parts holding very little to no detectable carbon consist of coarser sandy material estimated to an age between 39,000 and 18,000 years before present. For this period we assume sediment input of organic-poor material. Water isotope data derived from pore ice within the Yedoma core indicate a continuously cold state of the lower core parts, thereby ruling out a potential theory of Holocene influence. In consequence, we conclude that no strong organic matter decomposition took place in the sediments of the Yedoma core until today. In contrast, the Alas core from an adjacent thermokarst basin was strongly disturbed by lake development and permafrost thaw, and accordingly its sediment and carbon characteristics differed from those of the Yedoma core. The Alas core shows homogeneous ice content and the water isotope characteristics of a slightly more decomposed organic material; the findings of very carbon-poor core sections from the Yedoma core can be duplicated. The Yedoma deposition was likely influenced by fluvial regimes in nearby streams and the Lena River shifting with climate. The low carbon content and the clear stratigraphical layering of different sediment types suggest that the Yedoma deposits in the Yukechi area differ from other Yedoma sites regarding carbon stock and sedimentological composition. We conclude that sedimentary composition and deposition regimes of Yedoma may differ significantly within the Yedoma domain. The resulting heterogeneity should be taken into account for upscaling approaches on the Yedoma carbon stock. The Alas core gives clear insights into the future development of Cenral Yakutian Yedoma deposits. Other/Unknown Material Ice lena river permafrost Thermokarst Yakutia Siberia Copernicus Publications: E-Journals |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Permafrost ground is one of the largest repositories of stored terrestrial natural carbon and might become a carbon source with ongoing global warming. In particular, syngenetically frozen ice-rich Yedoma deposits originating from the late Pleistocene store a large amount of carbon. This carbon has not yet become part of the recent carbon cycle. With this study of Yedoma and associated Alas deposits in Central Yakutia we aim to understand the local sediment genesis and its effect on permafrost carbon storage. For this purpose, we investigated the Yukechi Alas area (61.76495° N, 130.46664° E), a thermokarst landscape degrading into Yedoma in Central Yakutia. Two sediment cores (Yedoma upland, 22.35 m depth, and Alas basin, 19.80 m depth) were drilled in 2015. We analyzed for ice content, total carbon and total nitrogen content, total organic carbon content, stable oxygen and hydrogen isotopes, stable carbon isotopes, mass specific magnetic susceptibility, grain size distribution, and radiocarbon ages. Samples taken from both cores were radiocarbon-dated up to 50,000 years before present. The laboratory analyses of both cores revealed very low carbon contents down to several meters depth. Those core parts holding very little to no detectable carbon consist of coarser sandy material estimated to an age between 39,000 and 18,000 years before present. For this period we assume sediment input of organic-poor material. Water isotope data derived from pore ice within the Yedoma core indicate a continuously cold state of the lower core parts, thereby ruling out a potential theory of Holocene influence. In consequence, we conclude that no strong organic matter decomposition took place in the sediments of the Yedoma core until today. In contrast, the Alas core from an adjacent thermokarst basin was strongly disturbed by lake development and permafrost thaw, and accordingly its sediment and carbon characteristics differed from those of the Yedoma core. The Alas core shows homogeneous ice content and the water isotope characteristics of a slightly more decomposed organic material; the findings of very carbon-poor core sections from the Yedoma core can be duplicated. The Yedoma deposition was likely influenced by fluvial regimes in nearby streams and the Lena River shifting with climate. The low carbon content and the clear stratigraphical layering of different sediment types suggest that the Yedoma deposits in the Yukechi area differ from other Yedoma sites regarding carbon stock and sedimentological composition. We conclude that sedimentary composition and deposition regimes of Yedoma may differ significantly within the Yedoma domain. The resulting heterogeneity should be taken into account for upscaling approaches on the Yedoma carbon stock. The Alas core gives clear insights into the future development of Cenral Yakutian Yedoma deposits. |
format |
Other/Unknown Material |
author |
Windirsch, Torben Grosse, Guido Ulrich, Mathias Schirrmeister, Lutz Fedorov, Alexander N. Konstantinov, Pavel Ya. Fuchs, Matthias Jongejans, Loeka L. Wolter, Juliane Strauss, Jens |
spellingShingle |
Windirsch, Torben Grosse, Guido Ulrich, Mathias Schirrmeister, Lutz Fedorov, Alexander N. Konstantinov, Pavel Ya. Fuchs, Matthias Jongejans, Loeka L. Wolter, Juliane Strauss, Jens Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia |
author_facet |
Windirsch, Torben Grosse, Guido Ulrich, Mathias Schirrmeister, Lutz Fedorov, Alexander N. Konstantinov, Pavel Ya. Fuchs, Matthias Jongejans, Loeka L. Wolter, Juliane Strauss, Jens |
author_sort |
Windirsch, Torben |
title |
Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia |
title_short |
Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia |
title_full |
Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia |
title_fullStr |
Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia |
title_full_unstemmed |
Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia |
title_sort |
organic carbon characteristics in ice-rich permafrost in alas and yedoma deposits, central yakutia, siberia |
publishDate |
2020 |
url |
https://doi.org/10.5194/bg-2019-470 https://www.biogeosciences-discuss.net/bg-2019-470/ |
genre |
Ice lena river permafrost Thermokarst Yakutia Siberia |
genre_facet |
Ice lena river permafrost Thermokarst Yakutia Siberia |
op_source |
eISSN: 1726-4189 |
op_relation |
info:eu-repo/grantAgreement/EC/FP7/338335 doi:10.5194/bg-2019-470 https://www.biogeosciences-discuss.net/bg-2019-470/ |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-2019-470 |
_version_ |
1766027585244889088 |