Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators
Global warming in high latitudes causes destabilization of vulnerable permafrost deposits followed by massive thaw-release of organic carbon. Permafrost-derived carbon may be buried in the nearshore sediments, transported towards the deeper basins or degraded into the greenhouse gases, potentially i...
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2020
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ftdoajarticles:oai:doaj.org/article:d8a5e306d9e0420e9fab5e6f5e841131 2023-05-15T15:15:41+02:00 Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators Elena Gershelis Andrey Grinko Irina Oberemok Elizaveta Klevantseva Natalina Poltavskaya Alexey Ruban Denis Chernykh Andrey Leonov Natalia Guseva Igor Semiletov 2020-12-01T00:00:00Z https://doi.org/10.3390/w12123511 https://doaj.org/article/d8a5e306d9e0420e9fab5e6f5e841131 EN eng MDPI AG https://www.mdpi.com/2073-4441/12/12/3511 https://doaj.org/toc/2073-4441 doi:10.3390/w12123511 2073-4441 https://doaj.org/article/d8a5e306d9e0420e9fab5e6f5e841131 Water, Vol 12, Iss 3511, p 3511 (2020) organic carbon biomarkers Rock-Eval pyrolysis grain size permafrost surface sediments Hydraulic engineering TC1-978 Water supply for domestic and industrial purposes TD201-500 article 2020 ftdoajarticles https://doi.org/10.3390/w12123511 2022-12-31T04:46:46Z Global warming in high latitudes causes destabilization of vulnerable permafrost deposits followed by massive thaw-release of organic carbon. Permafrost-derived carbon may be buried in the nearshore sediments, transported towards the deeper basins or degraded into the greenhouse gases, potentially initiating a positive feedback to climate change. In the present study, we aim to identify the sources, distribution and degradation state of organic matter (OM) stored in the surface sediments of the Laptev Sea (LS), which receives a large input of terrestrial carbon from both Lena River discharge and intense coastal erosion. We applied a suite of geochemical indicators including the Rock Eval parameters, traditionally used for the matured OM characterization, and terrestrial lipid biomarkers. In addition, we analyzed a comprehensive grain size data in order to assess hydrodynamic sedimentation regime across the LS shelf. Rock-Eval (RE) data characterize LS sedimentary OM with generally low hydrogen index (100–200 mg HC/g TOC) and oxygen index (200 and 300 CO 2 /g TOC) both increasing off to the continental slope. According to T peak values, there is a clear regional distinction between two groups (369–401 °C for the inner and mid shelf; 451–464 °C for the outer shelf). We suggest that permafrost-derived OM is traced across the shallow and mid depths with high T peak and slightly elevated HI values if compared to other Arctic continental margins. Molecular-based degradation indicators show a trend to more degraded terrestrial OC with increasing distance from the coast corroborating with RE results. However, we observed much less variation of the degradation markers down to the deeper sampling horizons, which supports the notion that the most active OM degradation in LS land-shelf system takes part during the cross-shelf transport, not while getting buried deeper. Article in Journal/Newspaper Arctic Climate change Global warming laptev Laptev Sea lena river permafrost Directory of Open Access Journals: DOAJ Articles Arctic Laptev Sea Water 12 12 3511 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
organic carbon biomarkers Rock-Eval pyrolysis grain size permafrost surface sediments Hydraulic engineering TC1-978 Water supply for domestic and industrial purposes TD201-500 |
spellingShingle |
organic carbon biomarkers Rock-Eval pyrolysis grain size permafrost surface sediments Hydraulic engineering TC1-978 Water supply for domestic and industrial purposes TD201-500 Elena Gershelis Andrey Grinko Irina Oberemok Elizaveta Klevantseva Natalina Poltavskaya Alexey Ruban Denis Chernykh Andrey Leonov Natalia Guseva Igor Semiletov Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators |
topic_facet |
organic carbon biomarkers Rock-Eval pyrolysis grain size permafrost surface sediments Hydraulic engineering TC1-978 Water supply for domestic and industrial purposes TD201-500 |
description |
Global warming in high latitudes causes destabilization of vulnerable permafrost deposits followed by massive thaw-release of organic carbon. Permafrost-derived carbon may be buried in the nearshore sediments, transported towards the deeper basins or degraded into the greenhouse gases, potentially initiating a positive feedback to climate change. In the present study, we aim to identify the sources, distribution and degradation state of organic matter (OM) stored in the surface sediments of the Laptev Sea (LS), which receives a large input of terrestrial carbon from both Lena River discharge and intense coastal erosion. We applied a suite of geochemical indicators including the Rock Eval parameters, traditionally used for the matured OM characterization, and terrestrial lipid biomarkers. In addition, we analyzed a comprehensive grain size data in order to assess hydrodynamic sedimentation regime across the LS shelf. Rock-Eval (RE) data characterize LS sedimentary OM with generally low hydrogen index (100–200 mg HC/g TOC) and oxygen index (200 and 300 CO 2 /g TOC) both increasing off to the continental slope. According to T peak values, there is a clear regional distinction between two groups (369–401 °C for the inner and mid shelf; 451–464 °C for the outer shelf). We suggest that permafrost-derived OM is traced across the shallow and mid depths with high T peak and slightly elevated HI values if compared to other Arctic continental margins. Molecular-based degradation indicators show a trend to more degraded terrestrial OC with increasing distance from the coast corroborating with RE results. However, we observed much less variation of the degradation markers down to the deeper sampling horizons, which supports the notion that the most active OM degradation in LS land-shelf system takes part during the cross-shelf transport, not while getting buried deeper. |
format |
Article in Journal/Newspaper |
author |
Elena Gershelis Andrey Grinko Irina Oberemok Elizaveta Klevantseva Natalina Poltavskaya Alexey Ruban Denis Chernykh Andrey Leonov Natalia Guseva Igor Semiletov |
author_facet |
Elena Gershelis Andrey Grinko Irina Oberemok Elizaveta Klevantseva Natalina Poltavskaya Alexey Ruban Denis Chernykh Andrey Leonov Natalia Guseva Igor Semiletov |
author_sort |
Elena Gershelis |
title |
Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators |
title_short |
Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators |
title_full |
Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators |
title_fullStr |
Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators |
title_full_unstemmed |
Composition of Sedimentary Organic Matter across the Laptev Sea Shelf: Evidences from Rock-Eval Parameters and Molecular Indicators |
title_sort |
composition of sedimentary organic matter across the laptev sea shelf: evidences from rock-eval parameters and molecular indicators |
publisher |
MDPI AG |
publishDate |
2020 |
url |
https://doi.org/10.3390/w12123511 https://doaj.org/article/d8a5e306d9e0420e9fab5e6f5e841131 |
geographic |
Arctic Laptev Sea |
geographic_facet |
Arctic Laptev Sea |
genre |
Arctic Climate change Global warming laptev Laptev Sea lena river permafrost |
genre_facet |
Arctic Climate change Global warming laptev Laptev Sea lena river permafrost |
op_source |
Water, Vol 12, Iss 3511, p 3511 (2020) |
op_relation |
https://www.mdpi.com/2073-4441/12/12/3511 https://doaj.org/toc/2073-4441 doi:10.3390/w12123511 2073-4441 https://doaj.org/article/d8a5e306d9e0420e9fab5e6f5e841131 |
op_doi |
https://doi.org/10.3390/w12123511 |
container_title |
Water |
container_volume |
12 |
container_issue |
12 |
container_start_page |
3511 |
_version_ |
1766346038814179328 |