Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain
Ice-rich permafrost has been subject to abrupt thaw and thermokarst formation in the past and is vulnerable to current global warming. The ice-rich permafrost domain includes Yedoma sediments that have never thawed since deposition during the late Pleistocene and Alas sediments that were formed by p...
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ftdoajarticles:oai:doaj.org/article:699aaaef7de2435eb60c79b8d61ff489 2023-05-15T15:16:15+02:00 Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain Arthur Monhonval Jens Strauss Elisabeth Mauclet Catherine Hirst Nathan Bemelmans Guido Grosse Lutz Schirrmeister Matthias Fuchs Sophie Opfergelt 2021-07-01T00:00:00Z https://doi.org/10.3389/feart.2021.703339 https://doaj.org/article/699aaaef7de2435eb60c79b8d61ff489 EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/feart.2021.703339/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.703339 https://doaj.org/article/699aaaef7de2435eb60c79b8d61ff489 Frontiers in Earth Science, Vol 9 (2021) permafrost thaw redox processes carbon stabilization arctic subarctic Science Q article 2021 ftdoajarticles https://doi.org/10.3389/feart.2021.703339 2022-12-31T05:40:16Z Ice-rich permafrost has been subject to abrupt thaw and thermokarst formation in the past and is vulnerable to current global warming. The ice-rich permafrost domain includes Yedoma sediments that have never thawed since deposition during the late Pleistocene and Alas sediments that were formed by previous thermokarst processes during the Lateglacial and Holocene warming. Permafrost thaw unlocks organic carbon (OC) and minerals from these deposits and exposes OC to mineralization. A portion of the OC can be associated with iron (Fe), a redox-sensitive element acting as a trap for OC. Post-depositional thaw processes may have induced changes in redox conditions in these deposits and thereby affected Fe distribution and interactions between OC and Fe, with knock-on effects on the role that Fe plays in mediating present day OC mineralization. To test this hypothesis, we measured Fe concentrations and proportion of Fe oxides and Fe complexed with OC in unthawed Yedoma and previously thawed Alas deposits. Total Fe concentrations were determined on 1,292 sediment samples from the Yedoma domain using portable X-ray fluorescence; these concentrations were corrected for trueness using a calibration based on a subset of 144 samples measured by inductively coupled plasma optical emission spectrometry after alkaline fusion (R2 = 0.95). The total Fe concentration is stable with depth in Yedoma deposits, but we observe a depletion or accumulation of total Fe in Alas deposits, which experienced previous thaw and/or flooding events. Selective Fe extractions targeting reactive forms of Fe on unthawed and previously thawed deposits highlight that about 25% of the total Fe is present as reactive species, either as crystalline or amorphous oxides, or complexed with OC, with no significant difference in proportions of reactive Fe between Yedoma and Alas deposits. These results suggest that redox driven processes during past thermokarst formation impact the present-day distribution of total Fe, and thereby the total amount of ... Article in Journal/Newspaper Arctic Global warming Ice permafrost Subarctic Thermokarst Directory of Open Access Journals: DOAJ Articles Arctic Frontiers in Earth Science 9 |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
permafrost thaw redox processes carbon stabilization arctic subarctic Science Q |
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permafrost thaw redox processes carbon stabilization arctic subarctic Science Q Arthur Monhonval Jens Strauss Elisabeth Mauclet Catherine Hirst Nathan Bemelmans Guido Grosse Lutz Schirrmeister Matthias Fuchs Sophie Opfergelt Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain |
topic_facet |
permafrost thaw redox processes carbon stabilization arctic subarctic Science Q |
description |
Ice-rich permafrost has been subject to abrupt thaw and thermokarst formation in the past and is vulnerable to current global warming. The ice-rich permafrost domain includes Yedoma sediments that have never thawed since deposition during the late Pleistocene and Alas sediments that were formed by previous thermokarst processes during the Lateglacial and Holocene warming. Permafrost thaw unlocks organic carbon (OC) and minerals from these deposits and exposes OC to mineralization. A portion of the OC can be associated with iron (Fe), a redox-sensitive element acting as a trap for OC. Post-depositional thaw processes may have induced changes in redox conditions in these deposits and thereby affected Fe distribution and interactions between OC and Fe, with knock-on effects on the role that Fe plays in mediating present day OC mineralization. To test this hypothesis, we measured Fe concentrations and proportion of Fe oxides and Fe complexed with OC in unthawed Yedoma and previously thawed Alas deposits. Total Fe concentrations were determined on 1,292 sediment samples from the Yedoma domain using portable X-ray fluorescence; these concentrations were corrected for trueness using a calibration based on a subset of 144 samples measured by inductively coupled plasma optical emission spectrometry after alkaline fusion (R2 = 0.95). The total Fe concentration is stable with depth in Yedoma deposits, but we observe a depletion or accumulation of total Fe in Alas deposits, which experienced previous thaw and/or flooding events. Selective Fe extractions targeting reactive forms of Fe on unthawed and previously thawed deposits highlight that about 25% of the total Fe is present as reactive species, either as crystalline or amorphous oxides, or complexed with OC, with no significant difference in proportions of reactive Fe between Yedoma and Alas deposits. These results suggest that redox driven processes during past thermokarst formation impact the present-day distribution of total Fe, and thereby the total amount of ... |
format |
Article in Journal/Newspaper |
author |
Arthur Monhonval Jens Strauss Elisabeth Mauclet Catherine Hirst Nathan Bemelmans Guido Grosse Lutz Schirrmeister Matthias Fuchs Sophie Opfergelt |
author_facet |
Arthur Monhonval Jens Strauss Elisabeth Mauclet Catherine Hirst Nathan Bemelmans Guido Grosse Lutz Schirrmeister Matthias Fuchs Sophie Opfergelt |
author_sort |
Arthur Monhonval |
title |
Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain |
title_short |
Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain |
title_full |
Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain |
title_fullStr |
Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain |
title_full_unstemmed |
Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain |
title_sort |
iron redistribution upon thermokarst processes in the yedoma domain |
publisher |
Frontiers Media S.A. |
publishDate |
2021 |
url |
https://doi.org/10.3389/feart.2021.703339 https://doaj.org/article/699aaaef7de2435eb60c79b8d61ff489 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Global warming Ice permafrost Subarctic Thermokarst |
genre_facet |
Arctic Global warming Ice permafrost Subarctic Thermokarst |
op_source |
Frontiers in Earth Science, Vol 9 (2021) |
op_relation |
https://www.frontiersin.org/articles/10.3389/feart.2021.703339/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.703339 https://doaj.org/article/699aaaef7de2435eb60c79b8d61ff489 |
op_doi |
https://doi.org/10.3389/feart.2021.703339 |
container_title |
Frontiers in Earth Science |
container_volume |
9 |
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1766346533693816832 |