Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies
Enhanced warming of the Northern high latitudes has intensified thermokarst processes throughout the permafrost zone. Retrogressive thaw slumps (RTS), where thaw-driven erosion caused by ground ice melt creates terrain disturbances extending over tens of hectares, represent particularly dynamic ther...
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Online Access: | https://doi.org/10.1088/1748-9326/abee4b https://doaj.org/article/b8c3350c3fdd48cc8da325409e2c336a |
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ftdoajarticles:oai:doaj.org/article:b8c3350c3fdd48cc8da325409e2c336a 2023-09-05T13:17:45+02:00 Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies Lisa Bröder Kirsi Keskitalo Scott Zolkos Sarah Shakil Suzanne E Tank Steve V Kokelj Tommaso Tesi Bart E Van Dongen Negar Haghipour Timothy I Eglinton Jorien E Vonk 2021-01-01T00:00:00Z https://doi.org/10.1088/1748-9326/abee4b https://doaj.org/article/b8c3350c3fdd48cc8da325409e2c336a EN eng IOP Publishing https://doi.org/10.1088/1748-9326/abee4b https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/abee4b 1748-9326 https://doaj.org/article/b8c3350c3fdd48cc8da325409e2c336a Environmental Research Letters, Vol 16, Iss 5, p 054059 (2021) carbon cycle climate change cryosphere thermokarst Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 article 2021 ftdoajarticles https://doi.org/10.1088/1748-9326/abee4b 2023-08-13T00:37:14Z Enhanced warming of the Northern high latitudes has intensified thermokarst processes throughout the permafrost zone. Retrogressive thaw slumps (RTS), where thaw-driven erosion caused by ground ice melt creates terrain disturbances extending over tens of hectares, represent particularly dynamic thermokarst features. Biogeochemical transformation of the mobilized substrate may release CO _2 to the atmosphere and impact downstream ecosystems, yet its fate remains unclear. The Peel Plateau in northwestern Canada hosts some of the largest RTS features in the Arctic. Here, thick deposits of Pleistocene-aged glacial tills are overlain by a thinner layer of relatively organic-rich Holocene-aged permafrost that aggraded upward following deeper thaw and soil development during the early Holocene warm period. In this study, we characterize exposed soil layers and the mobilized material by analysing sediment properties and organic matter composition in active layer, Holocene and Pleistocene permafrost, recently thawed debris deposits and fresh deposits of slump outflow from four separate RTS features. We found that organic matter content, radiocarbon age and biomarker concentrations in debris and outflow deposits from all four sites were most similar to permafrost soils, with a lesser influence of the organic-rich active layer. Lipid biomarkers suggested a significant contribution of petrogenic carbon especially in Pleistocene permafrost. Active layer samples contained abundant intrinsically labile macromolecular components (polysaccharides, lignin markers, phenolic and N-containing compounds). All other samples were dominated by degraded organic constituents. Active layer soils, although heterogeneous, also had the highest median grain sizes, whereas debris and runoff deposits consisted of finer mineral grains and were generally more homogeneous, similar to permafrost. We thus infer that both organic matter degradation and hydrodynamic sorting during transport affect the mobilized material. Determining the relative ... Article in Journal/Newspaper Arctic Climate change Ice permafrost Thermokarst Directory of Open Access Journals: DOAJ Articles Arctic Canada Environmental Research Letters 16 5 054059 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
carbon cycle climate change cryosphere thermokarst Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
spellingShingle |
carbon cycle climate change cryosphere thermokarst Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 Lisa Bröder Kirsi Keskitalo Scott Zolkos Sarah Shakil Suzanne E Tank Steve V Kokelj Tommaso Tesi Bart E Van Dongen Negar Haghipour Timothy I Eglinton Jorien E Vonk Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies |
topic_facet |
carbon cycle climate change cryosphere thermokarst Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
description |
Enhanced warming of the Northern high latitudes has intensified thermokarst processes throughout the permafrost zone. Retrogressive thaw slumps (RTS), where thaw-driven erosion caused by ground ice melt creates terrain disturbances extending over tens of hectares, represent particularly dynamic thermokarst features. Biogeochemical transformation of the mobilized substrate may release CO _2 to the atmosphere and impact downstream ecosystems, yet its fate remains unclear. The Peel Plateau in northwestern Canada hosts some of the largest RTS features in the Arctic. Here, thick deposits of Pleistocene-aged glacial tills are overlain by a thinner layer of relatively organic-rich Holocene-aged permafrost that aggraded upward following deeper thaw and soil development during the early Holocene warm period. In this study, we characterize exposed soil layers and the mobilized material by analysing sediment properties and organic matter composition in active layer, Holocene and Pleistocene permafrost, recently thawed debris deposits and fresh deposits of slump outflow from four separate RTS features. We found that organic matter content, radiocarbon age and biomarker concentrations in debris and outflow deposits from all four sites were most similar to permafrost soils, with a lesser influence of the organic-rich active layer. Lipid biomarkers suggested a significant contribution of petrogenic carbon especially in Pleistocene permafrost. Active layer samples contained abundant intrinsically labile macromolecular components (polysaccharides, lignin markers, phenolic and N-containing compounds). All other samples were dominated by degraded organic constituents. Active layer soils, although heterogeneous, also had the highest median grain sizes, whereas debris and runoff deposits consisted of finer mineral grains and were generally more homogeneous, similar to permafrost. We thus infer that both organic matter degradation and hydrodynamic sorting during transport affect the mobilized material. Determining the relative ... |
format |
Article in Journal/Newspaper |
author |
Lisa Bröder Kirsi Keskitalo Scott Zolkos Sarah Shakil Suzanne E Tank Steve V Kokelj Tommaso Tesi Bart E Van Dongen Negar Haghipour Timothy I Eglinton Jorien E Vonk |
author_facet |
Lisa Bröder Kirsi Keskitalo Scott Zolkos Sarah Shakil Suzanne E Tank Steve V Kokelj Tommaso Tesi Bart E Van Dongen Negar Haghipour Timothy I Eglinton Jorien E Vonk |
author_sort |
Lisa Bröder |
title |
Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies |
title_short |
Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies |
title_full |
Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies |
title_fullStr |
Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies |
title_full_unstemmed |
Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies |
title_sort |
preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies |
publisher |
IOP Publishing |
publishDate |
2021 |
url |
https://doi.org/10.1088/1748-9326/abee4b https://doaj.org/article/b8c3350c3fdd48cc8da325409e2c336a |
geographic |
Arctic Canada |
geographic_facet |
Arctic Canada |
genre |
Arctic Climate change Ice permafrost Thermokarst |
genre_facet |
Arctic Climate change Ice permafrost Thermokarst |
op_source |
Environmental Research Letters, Vol 16, Iss 5, p 054059 (2021) |
op_relation |
https://doi.org/10.1088/1748-9326/abee4b https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/abee4b 1748-9326 https://doaj.org/article/b8c3350c3fdd48cc8da325409e2c336a |
op_doi |
https://doi.org/10.1088/1748-9326/abee4b |
container_title |
Environmental Research Letters |
container_volume |
16 |
container_issue |
5 |
container_start_page |
054059 |
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1776198805473984512 |