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 (CH 4 ) in sediments as gas hydrate and free gas. Although release of this CH 4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water...
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ftdoajarticles:oai:doaj.org/article:ea28cec3396e4317bdb5cde2810c1555 2023-05-15T15:17:39+02:00 Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations C. M. Miller G. R. Dickens M. Jakobsson C. Johansson A. Koshurnikov M. O'Regan F. Muschitiello C. Stranne C.-M. Mörth 2017-06-01T00:00:00Z https://doi.org/10.5194/bg-14-2929-2017 https://doaj.org/article/ea28cec3396e4317bdb5cde2810c1555 EN eng Copernicus Publications http://www.biogeosciences.net/14/2929/2017/bg-14-2929-2017.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-14-2929-2017 1726-4170 1726-4189 https://doaj.org/article/ea28cec3396e4317bdb5cde2810c1555 Biogeosciences, Vol 14, Pp 2929-2953 (2017) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2017 ftdoajarticles https://doi.org/10.5194/bg-14-2929-2017 2022-12-31T09:53:46Z Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH 4 ) in sediments as gas hydrate and free gas. Although release of this CH 4 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 CH 4 flux towards the seafloor, as inferred from profiles of dissolved sulfate (SO 4 2− ), alkalinity, and the δ 13 C of dissolved inorganic carbon (DIC), is negligible at all stations east of 143° E longitude. In the upper 8 m of these cores, downward SO 4 2− flux never exceeds 6.2 mol m −2 kyr −1 , the upward alkalinity flux never exceeds 6.8 mol m −2 kyr −1 , and δ 13 C composition of DIC ( δ 13 C-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 H 2 S. 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 SO 4 2− and alkalinity were 13.9 and 11.3 mol m −2 kyr −1 , respectively, the δ 13 C-DIC gradient was 5.6 ‰ m −1 , and Mn 2+ 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 CH 4 , 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 ... Article in Journal/Newspaper Arctic Arctic Ocean East Siberian Sea Lomonosov Ridge New Siberian Islands SWERUS-C3 Wrangel Island Directory of Open Access Journals: DOAJ Articles 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 |
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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 C. M. Miller G. R. Dickens M. Jakobsson C. Johansson A. Koshurnikov M. O'Regan F. Muschitiello C. Stranne C.-M. Mörth Pore water geochemistry along continental slopes north of the East Siberian Sea: inference of low methane concentrations |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH 4 ) in sediments as gas hydrate and free gas. Although release of this CH 4 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 CH 4 flux towards the seafloor, as inferred from profiles of dissolved sulfate (SO 4 2− ), alkalinity, and the δ 13 C of dissolved inorganic carbon (DIC), is negligible at all stations east of 143° E longitude. In the upper 8 m of these cores, downward SO 4 2− flux never exceeds 6.2 mol m −2 kyr −1 , the upward alkalinity flux never exceeds 6.8 mol m −2 kyr −1 , and δ 13 C composition of DIC ( δ 13 C-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 H 2 S. 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 SO 4 2− and alkalinity were 13.9 and 11.3 mol m −2 kyr −1 , respectively, the δ 13 C-DIC gradient was 5.6 ‰ m −1 , and Mn 2+ 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 CH 4 , 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 ... |
format |
Article in Journal/Newspaper |
author |
C. M. Miller G. R. Dickens M. Jakobsson C. Johansson A. Koshurnikov M. O'Regan F. Muschitiello C. Stranne C.-M. Mörth |
author_facet |
C. M. Miller G. R. Dickens M. Jakobsson C. Johansson A. Koshurnikov M. O'Regan F. Muschitiello C. Stranne C.-M. Mörth |
author_sort |
C. M. Miller |
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 |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/bg-14-2929-2017 https://doaj.org/article/ea28cec3396e4317bdb5cde2810c1555 |
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_source |
Biogeosciences, Vol 14, Pp 2929-2953 (2017) |
op_relation |
http://www.biogeosciences.net/14/2929/2017/bg-14-2929-2017.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-14-2929-2017 1726-4170 1726-4189 https://doaj.org/article/ea28cec3396e4317bdb5cde2810c1555 |
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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1766347893947498496 |