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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Published in:Frontiers in Earth Science
Main Authors: Monhonval, Arthur, Strauss, Jens, Mauclet, Elisabeth, Hirst, Catherine, Bemelmans, Nathan, Grosse, Guido, Schirrmeister, Lutz, Fuchs, Matthias, Opfergelt, Sophie
Other Authors: UCL - SST/ELI/ELIE - Environmental Sciences
Format: Article in Journal/Newspaper
Language:English
Published: Frontiers Media SA 2021
Subjects:
Ice
Online Access:http://hdl.handle.net/2078.1/249652
https://doi.org/10.3389/feart.2021.703339
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spelling ftunistlouisbrus:oai:dial.uclouvain.be:boreal:249652 2024-05-12T08:00:35+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 UCL - SST/ELI/ELIE - Environmental Sciences 2021 http://hdl.handle.net/2078.1/249652 https://doi.org/10.3389/feart.2021.703339 eng eng Frontiers Media SA boreal:249652 http://hdl.handle.net/2078.1/249652 doi:10.3389/feart.2021.703339 urn:EISSN:2296-6463 info:eu-repo/semantics/openAccess Frontiers in Earth Science, Vol. 9 (2021) permafrost thaw redox processes carbon stabilization arctic subarctic info:eu-repo/semantics/article 2021 ftunistlouisbrus https://doi.org/10.3389/feart.2021.703339 2024-04-18T17:16:31Z 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 DIAL@USL-B (Université Saint-Louis, Bruxelles) Arctic Frontiers in Earth Science 9
institution Open Polar
collection DIAL@USL-B (Université Saint-Louis, Bruxelles)
op_collection_id ftunistlouisbrus
language English
topic permafrost
thaw
redox processes
carbon stabilization
arctic
subarctic
spellingShingle permafrost
thaw
redox processes
carbon stabilization
arctic
subarctic
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
topic_facet permafrost
thaw
redox processes
carbon stabilization
arctic
subarctic
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 ...
author2 UCL - SST/ELI/ELIE - Environmental Sciences
format Article in Journal/Newspaper
author Monhonval, Arthur
Strauss, Jens
Mauclet, Elisabeth
Hirst, Catherine
Bemelmans, Nathan
Grosse, Guido
Schirrmeister, Lutz
Fuchs, Matthias
Opfergelt, Sophie
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://hdl.handle.net/2078.1/249652
https://doi.org/10.3389/feart.2021.703339
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 boreal:249652
http://hdl.handle.net/2078.1/249652
doi:10.3389/feart.2021.703339
urn:EISSN:2296-6463
op_rights info:eu-repo/semantics/openAccess
op_doi https://doi.org/10.3389/feart.2021.703339
container_title Frontiers in Earth Science
container_volume 9
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