GDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation
Siberian permafrost contains a globally significant pool of organic carbon (OC) that is vulnerable to enhanced warming and subsequent release into the contemporary carbon cycle. OC release by both fluvial and coastal erosion has been reported in the region, but the behaviour of this material in the...
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ftdoajarticles:oai:doaj.org/article:c62b0b8699334b759e0e85683f74bc4e 2023-05-15T14:53:09+02:00 GDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation R. B. Sparkes A. Doğrul Selver J. Bischoff H. M. Talbot Ö. Gustafsson I. P. Semiletov O. V. Dudarev B. E. van Dongen 2015-06-01T00:00:00Z https://doi.org/10.5194/bg-12-3753-2015 https://doaj.org/article/c62b0b8699334b759e0e85683f74bc4e EN eng Copernicus Publications http://www.biogeosciences.net/12/3753/2015/bg-12-3753-2015.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-12-3753-2015 https://doaj.org/article/c62b0b8699334b759e0e85683f74bc4e Biogeosciences, Vol 12, Iss 12, Pp 3753-3768 (2015) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2015 ftdoajarticles https://doi.org/10.5194/bg-12-3753-2015 2022-12-30T22:47:14Z Siberian permafrost contains a globally significant pool of organic carbon (OC) that is vulnerable to enhanced warming and subsequent release into the contemporary carbon cycle. OC release by both fluvial and coastal erosion has been reported in the region, but the behaviour of this material in the Arctic Ocean is insufficiently understood. The balance between OC deposition and degradation on the East Siberian Arctic Shelf (ESAS) influences the climate–carbon cycle feedback in this area. In this study we couple measurements of glycerol dialkyl glycerol tetraethers (GDGTs) with bulk geochemical observations to improve knowledge of the sources of OC to the ESAS, the behaviour of specific biomarkers on the shelf and the balance between delivery and removal of different carbon pools. Branched GDGT (brGDGT) concentrations were highest close to river mouths, yet low in "ice complex" permafrost deposits, supporting recent observations that brGDGTs are mostly delivered by fluvial erosion, and may be a tracer for this in complex sedimentary environments. BrGDGT concentrations and the branched and isoprenoidal tetraether (BIT) index reduced quickly offshore, demonstrating a rapid reduction in river influence. Stable carbon isotope ratios changed at a different rate to the BIT index, suggesting not only that OC on the shelf is sourced from fluvial erosion but also that erosion of coastal sediments delivers substantial quantities of OC to the Arctic Ocean. A model of OC export from fluvial, coastal and marine sources is able to recreate the biomarker and bulk observations and provide estimates for the influence of fluvial and coastal OC across the whole shelf. The model shows that coastal erosion delivers 43 % of the OC and 87 % of the mineral sediment to the ESAS, but that rivers deliver 72 % of brGDGTs, indicating that brGDGTs can be used as a proxy for river-derived sediment. Article in Journal/Newspaper Arctic Arctic Ocean Ice permafrost Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean Biogeosciences 12 12 3753 3768 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 R. B. Sparkes A. Doğrul Selver J. Bischoff H. M. Talbot Ö. Gustafsson I. P. Semiletov O. V. Dudarev B. E. van Dongen GDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Siberian permafrost contains a globally significant pool of organic carbon (OC) that is vulnerable to enhanced warming and subsequent release into the contemporary carbon cycle. OC release by both fluvial and coastal erosion has been reported in the region, but the behaviour of this material in the Arctic Ocean is insufficiently understood. The balance between OC deposition and degradation on the East Siberian Arctic Shelf (ESAS) influences the climate–carbon cycle feedback in this area. In this study we couple measurements of glycerol dialkyl glycerol tetraethers (GDGTs) with bulk geochemical observations to improve knowledge of the sources of OC to the ESAS, the behaviour of specific biomarkers on the shelf and the balance between delivery and removal of different carbon pools. Branched GDGT (brGDGT) concentrations were highest close to river mouths, yet low in "ice complex" permafrost deposits, supporting recent observations that brGDGTs are mostly delivered by fluvial erosion, and may be a tracer for this in complex sedimentary environments. BrGDGT concentrations and the branched and isoprenoidal tetraether (BIT) index reduced quickly offshore, demonstrating a rapid reduction in river influence. Stable carbon isotope ratios changed at a different rate to the BIT index, suggesting not only that OC on the shelf is sourced from fluvial erosion but also that erosion of coastal sediments delivers substantial quantities of OC to the Arctic Ocean. A model of OC export from fluvial, coastal and marine sources is able to recreate the biomarker and bulk observations and provide estimates for the influence of fluvial and coastal OC across the whole shelf. The model shows that coastal erosion delivers 43 % of the OC and 87 % of the mineral sediment to the ESAS, but that rivers deliver 72 % of brGDGTs, indicating that brGDGTs can be used as a proxy for river-derived sediment. |
format |
Article in Journal/Newspaper |
author |
R. B. Sparkes A. Doğrul Selver J. Bischoff H. M. Talbot Ö. Gustafsson I. P. Semiletov O. V. Dudarev B. E. van Dongen |
author_facet |
R. B. Sparkes A. Doğrul Selver J. Bischoff H. M. Talbot Ö. Gustafsson I. P. Semiletov O. V. Dudarev B. E. van Dongen |
author_sort |
R. B. Sparkes |
title |
GDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation |
title_short |
GDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation |
title_full |
GDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation |
title_fullStr |
GDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation |
title_full_unstemmed |
GDGT distributions on the East Siberian Arctic Shelf: implications for organic carbon export, burial and degradation |
title_sort |
gdgt distributions on the east siberian arctic shelf: implications for organic carbon export, burial and degradation |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/bg-12-3753-2015 https://doaj.org/article/c62b0b8699334b759e0e85683f74bc4e |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Ice permafrost |
genre_facet |
Arctic Arctic Ocean Ice permafrost |
op_source |
Biogeosciences, Vol 12, Iss 12, Pp 3753-3768 (2015) |
op_relation |
http://www.biogeosciences.net/12/3753/2015/bg-12-3753-2015.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-12-3753-2015 https://doaj.org/article/c62b0b8699334b759e0e85683f74bc4e |
op_doi |
https://doi.org/10.5194/bg-12-3753-2015 |
container_title |
Biogeosciences |
container_volume |
12 |
container_issue |
12 |
container_start_page |
3753 |
op_container_end_page |
3768 |
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1766324559536979968 |