Permafrost Carbon and CO2 Pathways Differ at Contrasting Coastal Erosion Sites in the Canadian Arctic
Warming air and sea temperatures, longer open-water seasons and sea-level rise collectively promote the erosion of permafrost coasts in the Arctic, which profoundly impacts organic matter pathways. Although estimates on organic carbon (OC) fluxes from erosion exist for some parts of the Arctic, litt...
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2021
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ftdoajarticles:oai:doaj.org/article:cf44d24731814c598e7d8fd849215566 2023-05-15T14:51:14+02:00 Permafrost Carbon and CO2 Pathways Differ at Contrasting Coastal Erosion Sites in the Canadian Arctic George Tanski Lisa Bröder Dirk Wagner Christian Knoblauch Hugues Lantuit Christian Beer Torsten Sachs Michael Fritz Tommaso Tesi Boris P. Koch Negar Haghipour Timothy I. Eglinton Jens Strauss Jorien E. Vonk 2021-03-01T00:00:00Z https://doi.org/10.3389/feart.2021.630493 https://doaj.org/article/cf44d24731814c598e7d8fd849215566 EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/feart.2021.630493/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.630493 https://doaj.org/article/cf44d24731814c598e7d8fd849215566 Frontiers in Earth Science, Vol 9 (2021) Arctic coastal erosion carbon cycling biogeochemistry greenhouse gases carbon dioxide Science Q article 2021 ftdoajarticles https://doi.org/10.3389/feart.2021.630493 2022-12-31T06:30:14Z Warming air and sea temperatures, longer open-water seasons and sea-level rise collectively promote the erosion of permafrost coasts in the Arctic, which profoundly impacts organic matter pathways. Although estimates on organic carbon (OC) fluxes from erosion exist for some parts of the Arctic, little is known about how much OC is transformed into greenhouse gases (GHGs). In this study we investigated two different coastal erosion scenarios on Qikiqtaruk – Herschel Island (Canada) and estimate the potential for GHG formation. We distinguished between a delayed release represented by mud debris draining a coastal thermoerosional feature and a direct release represented by cliff debris at a low collapsing bluff. Carbon dioxide (CO2) production was measured during incubations at 4°C under aerobic conditions for two months and were modeled for four months and a full year. Our incubation results show that mud debris and cliff debris lost a considerable amount of OC as CO2 (2.5 ± 0.2 and 1.6 ± 0.3% of OC, respectively). Although relative OC losses were highest in mineral mud debris, higher initial OC content and fresh organic matter in cliff debris resulted in a ∼three times higher cumulative CO2 release (4.0 ± 0.9 compared to 1.4 ± 0.1 mg CO2 gdw–1), which was further increased by the addition of seawater. After four months, modeled OC losses were 4.9 ± 0.1 and 3.2 ± 0.3% in set-ups without seawater and 14.3 ± 0.1 and 7.3 ± 0.8% in set-ups with seawater. The results indicate that a delayed release may support substantial cycling of OC at relatively low CO2 production rates during long transit times onshore during the Arctic warm season. By contrast, direct erosion may result in a single CO2 pulse and less substantial OC cycling onshore as transfer times are short. Once eroded sediments are deposited in the nearshore, highest OC losses can be expected. We conclude that the release of CO2 from eroding permafrost coasts varies considerably between erosion types and residence time onshore. We emphasize the importance of ... Article in Journal/Newspaper Arctic Herschel Island permafrost Directory of Open Access Journals: DOAJ Articles Arctic Canada Herschel Island ENVELOPE(-139.089,-139.089,69.583,69.583) Frontiers in Earth Science 9 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Arctic coastal erosion carbon cycling biogeochemistry greenhouse gases carbon dioxide Science Q |
spellingShingle |
Arctic coastal erosion carbon cycling biogeochemistry greenhouse gases carbon dioxide Science Q George Tanski Lisa Bröder Dirk Wagner Christian Knoblauch Hugues Lantuit Christian Beer Torsten Sachs Michael Fritz Tommaso Tesi Boris P. Koch Negar Haghipour Timothy I. Eglinton Jens Strauss Jorien E. Vonk Permafrost Carbon and CO2 Pathways Differ at Contrasting Coastal Erosion Sites in the Canadian Arctic |
topic_facet |
Arctic coastal erosion carbon cycling biogeochemistry greenhouse gases carbon dioxide Science Q |
description |
Warming air and sea temperatures, longer open-water seasons and sea-level rise collectively promote the erosion of permafrost coasts in the Arctic, which profoundly impacts organic matter pathways. Although estimates on organic carbon (OC) fluxes from erosion exist for some parts of the Arctic, little is known about how much OC is transformed into greenhouse gases (GHGs). In this study we investigated two different coastal erosion scenarios on Qikiqtaruk – Herschel Island (Canada) and estimate the potential for GHG formation. We distinguished between a delayed release represented by mud debris draining a coastal thermoerosional feature and a direct release represented by cliff debris at a low collapsing bluff. Carbon dioxide (CO2) production was measured during incubations at 4°C under aerobic conditions for two months and were modeled for four months and a full year. Our incubation results show that mud debris and cliff debris lost a considerable amount of OC as CO2 (2.5 ± 0.2 and 1.6 ± 0.3% of OC, respectively). Although relative OC losses were highest in mineral mud debris, higher initial OC content and fresh organic matter in cliff debris resulted in a ∼three times higher cumulative CO2 release (4.0 ± 0.9 compared to 1.4 ± 0.1 mg CO2 gdw–1), which was further increased by the addition of seawater. After four months, modeled OC losses were 4.9 ± 0.1 and 3.2 ± 0.3% in set-ups without seawater and 14.3 ± 0.1 and 7.3 ± 0.8% in set-ups with seawater. The results indicate that a delayed release may support substantial cycling of OC at relatively low CO2 production rates during long transit times onshore during the Arctic warm season. By contrast, direct erosion may result in a single CO2 pulse and less substantial OC cycling onshore as transfer times are short. Once eroded sediments are deposited in the nearshore, highest OC losses can be expected. We conclude that the release of CO2 from eroding permafrost coasts varies considerably between erosion types and residence time onshore. We emphasize the importance of ... |
format |
Article in Journal/Newspaper |
author |
George Tanski Lisa Bröder Dirk Wagner Christian Knoblauch Hugues Lantuit Christian Beer Torsten Sachs Michael Fritz Tommaso Tesi Boris P. Koch Negar Haghipour Timothy I. Eglinton Jens Strauss Jorien E. Vonk |
author_facet |
George Tanski Lisa Bröder Dirk Wagner Christian Knoblauch Hugues Lantuit Christian Beer Torsten Sachs Michael Fritz Tommaso Tesi Boris P. Koch Negar Haghipour Timothy I. Eglinton Jens Strauss Jorien E. Vonk |
author_sort |
George Tanski |
title |
Permafrost Carbon and CO2 Pathways Differ at Contrasting Coastal Erosion Sites in the Canadian Arctic |
title_short |
Permafrost Carbon and CO2 Pathways Differ at Contrasting Coastal Erosion Sites in the Canadian Arctic |
title_full |
Permafrost Carbon and CO2 Pathways Differ at Contrasting Coastal Erosion Sites in the Canadian Arctic |
title_fullStr |
Permafrost Carbon and CO2 Pathways Differ at Contrasting Coastal Erosion Sites in the Canadian Arctic |
title_full_unstemmed |
Permafrost Carbon and CO2 Pathways Differ at Contrasting Coastal Erosion Sites in the Canadian Arctic |
title_sort |
permafrost carbon and co2 pathways differ at contrasting coastal erosion sites in the canadian arctic |
publisher |
Frontiers Media S.A. |
publishDate |
2021 |
url |
https://doi.org/10.3389/feart.2021.630493 https://doaj.org/article/cf44d24731814c598e7d8fd849215566 |
long_lat |
ENVELOPE(-139.089,-139.089,69.583,69.583) |
geographic |
Arctic Canada Herschel Island |
geographic_facet |
Arctic Canada Herschel Island |
genre |
Arctic Herschel Island permafrost |
genre_facet |
Arctic Herschel Island permafrost |
op_source |
Frontiers in Earth Science, Vol 9 (2021) |
op_relation |
https://www.frontiersin.org/articles/10.3389/feart.2021.630493/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2021.630493 https://doaj.org/article/cf44d24731814c598e7d8fd849215566 |
op_doi |
https://doi.org/10.3389/feart.2021.630493 |
container_title |
Frontiers in Earth Science |
container_volume |
9 |
_version_ |
1766322288419930112 |