Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations
Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH4) in sediments as gas hydrate and free gas. Although release of this CH4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water che...
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Online Access: | https://hdl.handle.net/1911/96034 https://doi.org/10.5194/bg-14-2929-2017 |
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ftriceuniv:oai:scholarship.rice.edu:1911/96034 2023-05-15T15:17:54+02:00 Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations Miller, Clint M. Dickens, Gerald R. Jakobsson, Martin Johansson, Carina Koshurnikov, Andrey O’Regan, Matt Muschitiello, Francesco Stranne, Christian Mörth, Carl-Magnus 2017 application/pdf https://hdl.handle.net/1911/96034 https://doi.org/10.5194/bg-14-2929-2017 eng eng European Geosciences Union Miller, Clint M., Dickens, Gerald R., Jakobsson, Martin, et al. "Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations." Biogeosciences, 14, (2017) European Geosciences Union: 2929-2953. https://doi.org/10.5194/bg-14-2929-2017. https://hdl.handle.net/1911/96034 https://doi.org/10.5194/bg-14-2929-2017 This work is distributed under the Creative Commons Attribution 3.0 License. https://creativecommons.org/licenses/by/3.0/ CC-BY Journal article Text publisher version 2017 ftriceuniv https://doi.org/10.5194/bg-14-2929-2017 2022-08-09T20:39:19Z Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH4) in sediments as gas hydrate and free gas. Although release of this CH4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water chemistry results from 32 sediment cores taken during Leg 2 of the 2014 joint Swedish–Russian–US Arctic Ocean Investigation of Climate–Cryosphere–Carbon Interactions (SWERUS-C3) expedition. The cores come from depth transects across the slope and rise extending between the Mendeleev and the Lomonosov ridges, north of Wrangel Island and the New Siberian Islands, respectively. Upward CH4 flux towards the seafloor, as inferred from profiles of dissolved sulfate (SO42−), alkalinity, and the δ13C of dissolved inorganic carbon (DIC), is negligible at all stations east of 143° E longitude. In the upper 8 m of these cores, downward SO42− flux never exceeds 6.2 mol m−2 kyr−1, the upward alkalinity flux never exceeds 6.8 mol m−2 kyr−1, and δ13C composition of DIC (δ13C-DIC) only moderately decreases with depth (−3.6 ‰ m−1 on average). Moreover, upon addition of Zn acetate to pore water samples, ZnS did not precipitate, indicating a lack of dissolved H2S. Phosphate, ammonium, and metal profiles reveal that metal oxide reduction by organic carbon dominates the geochemical environment and supports very low organic carbon turnover rates. A single core on the Lomonosov Ridge differs, as diffusive fluxes for SO42− and alkalinity were 13.9 and 11.3 mol m−2 kyr−1, respectively, the δ13C-DIC gradient was 5.6 ‰ m−1, and Mn2+ reduction terminated within 1.3 m of the seafloor. These are among the first pore water results generated from this vast climatically sensitive region, and they imply that abundant CH4, including gas hydrates, do not characterize the East Siberian Sea slope or rise along the investigated depth transects. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based on ... Article in Journal/Newspaper Arctic Arctic Ocean East Siberian Sea Lomonosov Ridge New Siberian Islands SWERUS-C3 Wrangel Island Rice University: Digital Scholarship Archive Arctic Arctic Ocean East Siberian Sea ENVELOPE(166.000,166.000,74.000,74.000) New Siberian Islands ENVELOPE(142.000,142.000,75.000,75.000) Wrangel Island ENVELOPE(-179.385,-179.385,71.244,71.244) Biogeosciences 14 12 2929 2953 |
institution |
Open Polar |
collection |
Rice University: Digital Scholarship Archive |
op_collection_id |
ftriceuniv |
language |
English |
description |
Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH4) in sediments as gas hydrate and free gas. Although release of this CH4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water chemistry results from 32 sediment cores taken during Leg 2 of the 2014 joint Swedish–Russian–US Arctic Ocean Investigation of Climate–Cryosphere–Carbon Interactions (SWERUS-C3) expedition. The cores come from depth transects across the slope and rise extending between the Mendeleev and the Lomonosov ridges, north of Wrangel Island and the New Siberian Islands, respectively. Upward CH4 flux towards the seafloor, as inferred from profiles of dissolved sulfate (SO42−), alkalinity, and the δ13C of dissolved inorganic carbon (DIC), is negligible at all stations east of 143° E longitude. In the upper 8 m of these cores, downward SO42− flux never exceeds 6.2 mol m−2 kyr−1, the upward alkalinity flux never exceeds 6.8 mol m−2 kyr−1, and δ13C composition of DIC (δ13C-DIC) only moderately decreases with depth (−3.6 ‰ m−1 on average). Moreover, upon addition of Zn acetate to pore water samples, ZnS did not precipitate, indicating a lack of dissolved H2S. Phosphate, ammonium, and metal profiles reveal that metal oxide reduction by organic carbon dominates the geochemical environment and supports very low organic carbon turnover rates. A single core on the Lomonosov Ridge differs, as diffusive fluxes for SO42− and alkalinity were 13.9 and 11.3 mol m−2 kyr−1, respectively, the δ13C-DIC gradient was 5.6 ‰ m−1, and Mn2+ reduction terminated within 1.3 m of the seafloor. These are among the first pore water results generated from this vast climatically sensitive region, and they imply that abundant CH4, including gas hydrates, do not characterize the East Siberian Sea slope or rise along the investigated depth transects. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based on ... |
format |
Article in Journal/Newspaper |
author |
Miller, Clint M. Dickens, Gerald R. Jakobsson, Martin Johansson, Carina Koshurnikov, Andrey O’Regan, Matt Muschitiello, Francesco Stranne, Christian Mörth, Carl-Magnus |
spellingShingle |
Miller, Clint M. Dickens, Gerald R. Jakobsson, Martin Johansson, Carina Koshurnikov, Andrey O’Regan, Matt Muschitiello, Francesco Stranne, Christian Mörth, Carl-Magnus Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations |
author_facet |
Miller, Clint M. Dickens, Gerald R. Jakobsson, Martin Johansson, Carina Koshurnikov, Andrey O’Regan, Matt Muschitiello, Francesco Stranne, Christian Mörth, Carl-Magnus |
author_sort |
Miller, Clint M. |
title |
Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations |
title_short |
Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations |
title_full |
Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations |
title_fullStr |
Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations |
title_full_unstemmed |
Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations |
title_sort |
pore water geochemistry along continental slopes north of the east siberian sea: inference of low methane concentrations |
publisher |
European Geosciences Union |
publishDate |
2017 |
url |
https://hdl.handle.net/1911/96034 https://doi.org/10.5194/bg-14-2929-2017 |
long_lat |
ENVELOPE(166.000,166.000,74.000,74.000) ENVELOPE(142.000,142.000,75.000,75.000) ENVELOPE(-179.385,-179.385,71.244,71.244) |
geographic |
Arctic Arctic Ocean East Siberian Sea New Siberian Islands Wrangel Island |
geographic_facet |
Arctic Arctic Ocean East Siberian Sea New Siberian Islands Wrangel Island |
genre |
Arctic Arctic Ocean East Siberian Sea Lomonosov Ridge New Siberian Islands SWERUS-C3 Wrangel Island |
genre_facet |
Arctic Arctic Ocean East Siberian Sea Lomonosov Ridge New Siberian Islands SWERUS-C3 Wrangel Island |
op_relation |
Miller, Clint M., Dickens, Gerald R., Jakobsson, Martin, et al. "Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations." Biogeosciences, 14, (2017) European Geosciences Union: 2929-2953. https://doi.org/10.5194/bg-14-2929-2017. https://hdl.handle.net/1911/96034 https://doi.org/10.5194/bg-14-2929-2017 |
op_rights |
This work is distributed under the Creative Commons Attribution 3.0 License. https://creativecommons.org/licenses/by/3.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/bg-14-2929-2017 |
container_title |
Biogeosciences |
container_volume |
14 |
container_issue |
12 |
container_start_page |
2929 |
op_container_end_page |
2953 |
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1766348160848887808 |