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...
Published in: | Frontiers in Earth Science |
---|---|
Main Authors: | , , , , , , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Frontiers Media SA
2021
|
Subjects: | |
Online Access: | http://dx.doi.org/10.3389/feart.2021.703339 https://www.frontiersin.org/articles/10.3389/feart.2021.703339/full |
id |
crfrontiers:10.3389/feart.2021.703339 |
---|---|
record_format |
openpolar |
spelling |
crfrontiers:10.3389/feart.2021.703339 2024-05-19T07:41:52+00:00 Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain Monhonval, Arthur Strauss, Jens Mauclet, Elisabeth Hirst, Catherine Bemelmans, Nathan Grosse, Guido Schirrmeister, Lutz Fuchs, Matthias Opfergelt, Sophie Horizon 2020 2021 http://dx.doi.org/10.3389/feart.2021.703339 https://www.frontiersin.org/articles/10.3389/feart.2021.703339/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Earth Science volume 9 ISSN 2296-6463 journal-article 2021 crfrontiers https://doi.org/10.3389/feart.2021.703339 2024-04-24T07:12:33Z 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 ( R 2 = 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 Ice permafrost Thermokarst Frontiers (Publisher) Frontiers in Earth Science 9 |
institution |
Open Polar |
collection |
Frontiers (Publisher) |
op_collection_id |
crfrontiers |
language |
unknown |
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 ( R 2 = 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 ... |
author2 |
Horizon 2020 |
format |
Article in Journal/Newspaper |
author |
Monhonval, Arthur Strauss, Jens Mauclet, Elisabeth Hirst, Catherine Bemelmans, Nathan Grosse, Guido Schirrmeister, Lutz Fuchs, Matthias Opfergelt, Sophie |
spellingShingle |
Monhonval, Arthur Strauss, Jens Mauclet, Elisabeth Hirst, Catherine Bemelmans, Nathan Grosse, Guido Schirrmeister, Lutz Fuchs, Matthias Opfergelt, Sophie Iron Redistribution Upon Thermokarst Processes in the Yedoma Domain |
author_facet |
Monhonval, Arthur Strauss, Jens Mauclet, Elisabeth Hirst, Catherine Bemelmans, Nathan Grosse, Guido Schirrmeister, Lutz Fuchs, Matthias Opfergelt, Sophie |
author_sort |
Monhonval, Arthur |
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 SA |
publishDate |
2021 |
url |
http://dx.doi.org/10.3389/feart.2021.703339 https://www.frontiersin.org/articles/10.3389/feart.2021.703339/full |
genre |
Ice permafrost Thermokarst |
genre_facet |
Ice permafrost Thermokarst |
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.2021.703339 |
container_title |
Frontiers in Earth Science |
container_volume |
9 |
_version_ |
1799481478469386240 |