Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment
The Siberian Arctic Sea shelf and slope is a key region for the degradation of terrestrial organic material transported from the organic-carbon-rich permafrost regions of Siberia. We report on sediment carbon mineralization rates based on O 2 microelectrode profiling; intact sediment core incubation...
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ftcopernicus:oai:publications.copernicus.org:bg58278 2023-05-15T15:05:52+02:00 Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment Brüchert, Volker Bröder, Lisa Sawicka, Joanna E. Tesi, Tommaso Joye, Samantha P. Sun, Xiaole Semiletov, Igor P. Samarkin, Vladimir A. 2019-01-17 application/pdf https://doi.org/10.5194/bg-15-471-2018 https://www.biogeosciences.net/15/471/2018/ eng eng doi:10.5194/bg-15-471-2018 https://www.biogeosciences.net/15/471/2018/ eISSN: 1726-4189 Text 2019 ftcopernicus https://doi.org/10.5194/bg-15-471-2018 2019-12-24T09:50:41Z The Siberian Arctic Sea shelf and slope is a key region for the degradation of terrestrial organic material transported from the organic-carbon-rich permafrost regions of Siberia. We report on sediment carbon mineralization rates based on O 2 microelectrode profiling; intact sediment core incubations; 35 S-sulfate tracer experiments; pore-water dissolved inorganic carbon (DIC); δ 13 C DIC and iron, manganese, and ammonium concentrations from 20 shelf and slope stations. This data set provides a spatial overview of sediment carbon mineralization rates and pathways over large parts of the outer Laptev and East Siberian Arctic shelf and slope and allows us to assess degradation rates and efficiency of carbon burial in these sediments. Rates of oxygen uptake and iron and manganese reduction were comparable to temperate shelf and slope environments, but bacterial sulfate reduction rates were comparatively low. In the topmost 50 cm of sediment, aerobic carbon mineralization dominated degradation and comprised on average 84 % of the depth-integrated carbon mineralization. Oxygen uptake rates and anaerobic carbon mineralization rates were higher in the eastern East Siberian Sea shelf compared to the Laptev Sea shelf. DIC ∕ NH <math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="3fe22ea21bb8c3940d1d54b092ea883d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-15-471-2018-ie00001.svg" width="8pt" height="15pt" src="bg-15-471-2018-ie00001.png"/></svg:svg> ratios in pore waters and the stable carbon isotope composition of remineralized DIC indicated that the degraded organic matter on the Siberian shelf and slope was a mixture of marine and terrestrial organic matter. Based on dual end-member calculations, the terrestrial organic carbon contribution varied between 32 and 36 %, with a higher contribution in the Laptev Sea than in the East Siberian Sea. Extrapolation of the measured degradation rates using isotope end-member apportionment over the outer shelf of the Laptev and East Siberian seas suggests that about 16 Tg C yr −1 is respired in the outer shelf seafloor sediment. Of the organic matter buried below the oxygen penetration depth, between 0.6 and 1.3 Tg C yr −1 is degraded by anaerobic processes, with a terrestrial organic carbon contribution ranging between 0.3 and 0.5 Tg yr −1 . Text Arctic East Siberian Sea laptev Laptev Sea permafrost Siberia Copernicus Publications: E-Journals Arctic East Siberian Sea ENVELOPE(166.000,166.000,74.000,74.000) Laptev Sea Biogeosciences 15 2 471 490 |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The Siberian Arctic Sea shelf and slope is a key region for the degradation of terrestrial organic material transported from the organic-carbon-rich permafrost regions of Siberia. We report on sediment carbon mineralization rates based on O 2 microelectrode profiling; intact sediment core incubations; 35 S-sulfate tracer experiments; pore-water dissolved inorganic carbon (DIC); δ 13 C DIC and iron, manganese, and ammonium concentrations from 20 shelf and slope stations. This data set provides a spatial overview of sediment carbon mineralization rates and pathways over large parts of the outer Laptev and East Siberian Arctic shelf and slope and allows us to assess degradation rates and efficiency of carbon burial in these sediments. Rates of oxygen uptake and iron and manganese reduction were comparable to temperate shelf and slope environments, but bacterial sulfate reduction rates were comparatively low. In the topmost 50 cm of sediment, aerobic carbon mineralization dominated degradation and comprised on average 84 % of the depth-integrated carbon mineralization. Oxygen uptake rates and anaerobic carbon mineralization rates were higher in the eastern East Siberian Sea shelf compared to the Laptev Sea shelf. DIC ∕ NH <math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="3fe22ea21bb8c3940d1d54b092ea883d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-15-471-2018-ie00001.svg" width="8pt" height="15pt" src="bg-15-471-2018-ie00001.png"/></svg:svg> ratios in pore waters and the stable carbon isotope composition of remineralized DIC indicated that the degraded organic matter on the Siberian shelf and slope was a mixture of marine and terrestrial organic matter. Based on dual end-member calculations, the terrestrial organic carbon contribution varied between 32 and 36 %, with a higher contribution in the Laptev Sea than in the East Siberian Sea. Extrapolation of the measured degradation rates using isotope end-member apportionment over the outer shelf of the Laptev and East Siberian seas suggests that about 16 Tg C yr −1 is respired in the outer shelf seafloor sediment. Of the organic matter buried below the oxygen penetration depth, between 0.6 and 1.3 Tg C yr −1 is degraded by anaerobic processes, with a terrestrial organic carbon contribution ranging between 0.3 and 0.5 Tg yr −1 . |
format |
Text |
author |
Brüchert, Volker Bröder, Lisa Sawicka, Joanna E. Tesi, Tommaso Joye, Samantha P. Sun, Xiaole Semiletov, Igor P. Samarkin, Vladimir A. |
spellingShingle |
Brüchert, Volker Bröder, Lisa Sawicka, Joanna E. Tesi, Tommaso Joye, Samantha P. Sun, Xiaole Semiletov, Igor P. Samarkin, Vladimir A. Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment |
author_facet |
Brüchert, Volker Bröder, Lisa Sawicka, Joanna E. Tesi, Tommaso Joye, Samantha P. Sun, Xiaole Semiletov, Igor P. Samarkin, Vladimir A. |
author_sort |
Brüchert, Volker |
title |
Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment |
title_short |
Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment |
title_full |
Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment |
title_fullStr |
Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment |
title_full_unstemmed |
Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment |
title_sort |
carbon mineralization in laptev and east siberian sea shelf and slope sediment |
publishDate |
2019 |
url |
https://doi.org/10.5194/bg-15-471-2018 https://www.biogeosciences.net/15/471/2018/ |
long_lat |
ENVELOPE(166.000,166.000,74.000,74.000) |
geographic |
Arctic East Siberian Sea Laptev Sea |
geographic_facet |
Arctic East Siberian Sea Laptev Sea |
genre |
Arctic East Siberian Sea laptev Laptev Sea permafrost Siberia |
genre_facet |
Arctic East Siberian Sea laptev Laptev Sea permafrost Siberia |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-15-471-2018 https://www.biogeosciences.net/15/471/2018/ |
op_doi |
https://doi.org/10.5194/bg-15-471-2018 |
container_title |
Biogeosciences |
container_volume |
15 |
container_issue |
2 |
container_start_page |
471 |
op_container_end_page |
490 |
_version_ |
1766337544210874368 |