Iron Dynamics during Thermokarst Processes in the Yedoma Domain and Implications for Interactions between Iron and Organic Carbon
Iron (Fe) plays a key role in mediating organic carbon (OC) decomposition rates in permafrost soils. Fe-bearing minerals stabilize OC through complexation, co-precipitation or aggregation processes and thus hinder degradation of OC. In addition, Fe(III) reduction can inhibit methanogenesis and decre...
Main Authors: | , , , , , , , , , , |
---|---|
Other Authors: | |
Format: | Conference Object |
Language: | English |
Published: |
2020
|
Subjects: | |
Online Access: | http://hdl.handle.net/2078.1/239965 |
id |
ftunivlouvain:oai:dial.uclouvain.be:boreal:239965 |
---|---|
record_format |
openpolar |
spelling |
ftunivlouvain:oai:dial.uclouvain.be:boreal:239965 2024-05-12T08:05:04+00:00 Iron Dynamics during Thermokarst Processes in the Yedoma Domain and Implications for Interactions between Iron and Organic Carbon Monhonval, Arthur Opfergelt, Sophie Mauclet, Elisabeth Hirst, Catherine Pereira, Benoît Vandeuren, Aubry Bemelmans, Nathan Grosse Guido Schirrmeister Lutz Fuchs Matthias AGU FALL MEETING UCL - SST/ELI/ELIE - Environmental Sciences 2020 http://hdl.handle.net/2078.1/239965 eng eng boreal:239965 http://hdl.handle.net/2078.1/239965 info:eu-repo/semantics/openAccess iron dynamics thermokarst processes Yedoma domain organic carbon Alaska info:eu-repo/semantics/conferenceObject 2020 ftunivlouvain 2024-04-17T16:42:12Z Iron (Fe) plays a key role in mediating organic carbon (OC) decomposition rates in permafrost soils. Fe-bearing minerals stabilize OC through complexation, co-precipitation or aggregation processes and thus hinder degradation of OC. In addition, Fe(III) reduction can inhibit methanogenesis and decrease warming potential of greenhouse gases release. Ice-rich permafrost is subject to abrupt thaw and thermokarst formation, which unlocks OC and minerals from deep deposits and exposes OC to mineralization. These ice-rich domains include Yedoma sediments that have never thawed since deposition and Alas sediments that have undergone previous thermokarst processes during the Lateglacial and Holocene warming periods. The post-depositional history of these sediments may affect the distribution and reactivity of Fe-bearing minerals and the role Fe plays in mediating present day OC mineralization. Here we quantify Fe concentrations, Fe spatial and depth distribution, and Fe mineralogy in unthawed Yedoma and previously thawed Alas deposits from the Yedoma domain (West Siberia, Laptev Sea region, Kolyma region, New Siberian Islands and Alaska). Total Fe concentrations of ice-rich Yedoma deposits and previously thawed Alas deposits were determined using a portable X-ray fluorescence (XRF) device. This non-destructive method allowed a total iron concentration assessment of Yedoma domain deposits based on 1292 sediment samples. Portable XRF-measured concentrations trueness were calibrated from alkaline fusion and inductively coupled plasma optical emission spectrometry (ICP-OES) measurement method on a subset of 144 samples (R² = 0.81). Fe extractions of unthawed and previously thawed deposits display that, on average, 25% of the total iron is considered as reactive species, either as crystalline or amorphous oxides, or complexed with OC, with no significant difference between Yedoma and Alas deposits. We observe a constant total Fe concentration in Yedoma deposits, but a depletion or accumulation of total Fe in Alas deposits, ... Conference Object Ice laptev Laptev Sea New Siberian Islands permafrost Thermokarst Alaska Siberia DIAL@UCLouvain (Université catholique de Louvain) Laptev Sea Kolyma ENVELOPE(161.000,161.000,69.500,69.500) New Siberian Islands ENVELOPE(142.000,142.000,75.000,75.000) |
institution |
Open Polar |
collection |
DIAL@UCLouvain (Université catholique de Louvain) |
op_collection_id |
ftunivlouvain |
language |
English |
topic |
iron dynamics thermokarst processes Yedoma domain organic carbon Alaska |
spellingShingle |
iron dynamics thermokarst processes Yedoma domain organic carbon Alaska Monhonval, Arthur Opfergelt, Sophie Mauclet, Elisabeth Hirst, Catherine Pereira, Benoît Vandeuren, Aubry Bemelmans, Nathan Grosse Guido Schirrmeister Lutz Fuchs Matthias AGU FALL MEETING Iron Dynamics during Thermokarst Processes in the Yedoma Domain and Implications for Interactions between Iron and Organic Carbon |
topic_facet |
iron dynamics thermokarst processes Yedoma domain organic carbon Alaska |
description |
Iron (Fe) plays a key role in mediating organic carbon (OC) decomposition rates in permafrost soils. Fe-bearing minerals stabilize OC through complexation, co-precipitation or aggregation processes and thus hinder degradation of OC. In addition, Fe(III) reduction can inhibit methanogenesis and decrease warming potential of greenhouse gases release. Ice-rich permafrost is subject to abrupt thaw and thermokarst formation, which unlocks OC and minerals from deep deposits and exposes OC to mineralization. These ice-rich domains include Yedoma sediments that have never thawed since deposition and Alas sediments that have undergone previous thermokarst processes during the Lateglacial and Holocene warming periods. The post-depositional history of these sediments may affect the distribution and reactivity of Fe-bearing minerals and the role Fe plays in mediating present day OC mineralization. Here we quantify Fe concentrations, Fe spatial and depth distribution, and Fe mineralogy in unthawed Yedoma and previously thawed Alas deposits from the Yedoma domain (West Siberia, Laptev Sea region, Kolyma region, New Siberian Islands and Alaska). Total Fe concentrations of ice-rich Yedoma deposits and previously thawed Alas deposits were determined using a portable X-ray fluorescence (XRF) device. This non-destructive method allowed a total iron concentration assessment of Yedoma domain deposits based on 1292 sediment samples. Portable XRF-measured concentrations trueness were calibrated from alkaline fusion and inductively coupled plasma optical emission spectrometry (ICP-OES) measurement method on a subset of 144 samples (R² = 0.81). Fe extractions of unthawed and previously thawed deposits display that, on average, 25% of the total iron is considered as reactive species, either as crystalline or amorphous oxides, or complexed with OC, with no significant difference between Yedoma and Alas deposits. We observe a constant total Fe concentration in Yedoma deposits, but a depletion or accumulation of total Fe in Alas deposits, ... |
author2 |
UCL - SST/ELI/ELIE - Environmental Sciences |
format |
Conference Object |
author |
Monhonval, Arthur Opfergelt, Sophie Mauclet, Elisabeth Hirst, Catherine Pereira, Benoît Vandeuren, Aubry Bemelmans, Nathan Grosse Guido Schirrmeister Lutz Fuchs Matthias AGU FALL MEETING |
author_facet |
Monhonval, Arthur Opfergelt, Sophie Mauclet, Elisabeth Hirst, Catherine Pereira, Benoît Vandeuren, Aubry Bemelmans, Nathan Grosse Guido Schirrmeister Lutz Fuchs Matthias AGU FALL MEETING |
author_sort |
Monhonval, Arthur |
title |
Iron Dynamics during Thermokarst Processes in the Yedoma Domain and Implications for Interactions between Iron and Organic Carbon |
title_short |
Iron Dynamics during Thermokarst Processes in the Yedoma Domain and Implications for Interactions between Iron and Organic Carbon |
title_full |
Iron Dynamics during Thermokarst Processes in the Yedoma Domain and Implications for Interactions between Iron and Organic Carbon |
title_fullStr |
Iron Dynamics during Thermokarst Processes in the Yedoma Domain and Implications for Interactions between Iron and Organic Carbon |
title_full_unstemmed |
Iron Dynamics during Thermokarst Processes in the Yedoma Domain and Implications for Interactions between Iron and Organic Carbon |
title_sort |
iron dynamics during thermokarst processes in the yedoma domain and implications for interactions between iron and organic carbon |
publishDate |
2020 |
url |
http://hdl.handle.net/2078.1/239965 |
long_lat |
ENVELOPE(161.000,161.000,69.500,69.500) ENVELOPE(142.000,142.000,75.000,75.000) |
geographic |
Laptev Sea Kolyma New Siberian Islands |
geographic_facet |
Laptev Sea Kolyma New Siberian Islands |
genre |
Ice laptev Laptev Sea New Siberian Islands permafrost Thermokarst Alaska Siberia |
genre_facet |
Ice laptev Laptev Sea New Siberian Islands permafrost Thermokarst Alaska Siberia |
op_relation |
boreal:239965 http://hdl.handle.net/2078.1/239965 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1798847321195151360 |