Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea
Biogeochemical cycling of silicon (Si) in the Barents Sea is under considerable pressure from physical and chemical changes, including dramatic warming and sea ice retreat, together with a decline in dissolved silicic acid (DSi) concentrations of Atlantic inflow waters since 1990. Associated changes...
Published in: | Geochimica et Cosmochimica Acta |
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Language: | English |
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Elsevier
2022
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ftnerc:oai:nora.nerc.ac.uk:532711 2023-05-15T14:27:32+02:00 Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea Ward, James P.J. Hendry, Katharine R. Arndt, Sandra Faust, Johan C. Freitas, Felipe S. Henley, Sian F. Krause, Jeffrey W. März, Christian Ng, Hong Chin Pickering, Rebecca A. Tessin, Allyson C. 2022-07-15 text http://nora.nerc.ac.uk/id/eprint/532711/ https://nora.nerc.ac.uk/id/eprint/532711/1/1-s2.0-S0016703722002216-main.pdf https://www.sciencedirect.com/science/article/pii/S0016703722002216 en eng Elsevier https://nora.nerc.ac.uk/id/eprint/532711/1/1-s2.0-S0016703722002216-main.pdf Ward, James P.J.; Hendry, Katharine R. orcid:0000-0002-0790-5895 Arndt, Sandra; Faust, Johan C.; Freitas, Felipe S.; Henley, Sian F.; Krause, Jeffrey W.; März, Christian; Ng, Hong Chin; Pickering, Rebecca A.; Tessin, Allyson C. 2022 Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea. Geochimica et Cosmochimica Acta, 329. 206-230. https://doi.org/10.1016/j.gca.2022.05.005 <https://doi.org/10.1016/j.gca.2022.05.005> cc_by_4 CC-BY Publication - Article PeerReviewed 2022 ftnerc https://doi.org/10.1016/j.gca.2022.05.005 2023-02-04T19:53:18Z Biogeochemical cycling of silicon (Si) in the Barents Sea is under considerable pressure from physical and chemical changes, including dramatic warming and sea ice retreat, together with a decline in dissolved silicic acid (DSi) concentrations of Atlantic inflow waters since 1990. Associated changes in the community composition of phytoplankton blooms will alter the material comprising the depositional flux, which will subsequently influence recycling processes at and within the seafloor. In this study we assess the predominant controls on the early diagenetic cycling of Si, a key nutrient in marine ecosystems, by combining stable isotopic analysis (Si) of pore water DSi and of operationally defined reactive pools of the solid phase. We show that low biogenic silica (BSi) contents (0.26–0.52 wt% or 92–185 mol g dry wt−1) drive correspondingly low asymptotic concentrations of pore water DSi of 100 M, relative to biosiliceous sediments (20 wt% BSi) wherein DSi can reach 900 M. While Barents Sea surface sediments appear almost devoid of BSi, we present evidence for the rapid recycling of bloom derived BSi that generates striking transient peaks in sediment pore water [DSi] of up to 300 M, which is a feature that is subject to future shifts in phytoplankton community compositions. Using a simple isotopic mass balance calculation we show that at two of three stations the pore water DSi pool at 0.5 cm below the seafloor (+0.96 to +1.36 ‰) is sourced from the mixing of core top waters (+1.46 to +1.69 ‰) with the dissolution of BSi (+0.82 to +1.50 ‰), supplemented with a lithogenic Si source (LSi) (−0.89 0.16‰). Further, our sediment pore water Si profiles uncover a coupling of the Si cycle with the redox cycling of metal oxides associated with isotopically light Si (−2.88 0.17‰). We suggest that a high LSi:BSi ratio and apparent metal oxide influence could lead to a degree of stability in the annual background benthic flux of DSi, despite current pressures on pelagic phytoplankton communities. Coupled with supporting ... Article in Journal/Newspaper Arctic Arctic Barents Sea Phytoplankton Sea ice Natural Environment Research Council: NERC Open Research Archive Arctic Barents Sea Geochimica et Cosmochimica Acta 329 206 230 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
Biogeochemical cycling of silicon (Si) in the Barents Sea is under considerable pressure from physical and chemical changes, including dramatic warming and sea ice retreat, together with a decline in dissolved silicic acid (DSi) concentrations of Atlantic inflow waters since 1990. Associated changes in the community composition of phytoplankton blooms will alter the material comprising the depositional flux, which will subsequently influence recycling processes at and within the seafloor. In this study we assess the predominant controls on the early diagenetic cycling of Si, a key nutrient in marine ecosystems, by combining stable isotopic analysis (Si) of pore water DSi and of operationally defined reactive pools of the solid phase. We show that low biogenic silica (BSi) contents (0.26–0.52 wt% or 92–185 mol g dry wt−1) drive correspondingly low asymptotic concentrations of pore water DSi of 100 M, relative to biosiliceous sediments (20 wt% BSi) wherein DSi can reach 900 M. While Barents Sea surface sediments appear almost devoid of BSi, we present evidence for the rapid recycling of bloom derived BSi that generates striking transient peaks in sediment pore water [DSi] of up to 300 M, which is a feature that is subject to future shifts in phytoplankton community compositions. Using a simple isotopic mass balance calculation we show that at two of three stations the pore water DSi pool at 0.5 cm below the seafloor (+0.96 to +1.36 ‰) is sourced from the mixing of core top waters (+1.46 to +1.69 ‰) with the dissolution of BSi (+0.82 to +1.50 ‰), supplemented with a lithogenic Si source (LSi) (−0.89 0.16‰). Further, our sediment pore water Si profiles uncover a coupling of the Si cycle with the redox cycling of metal oxides associated with isotopically light Si (−2.88 0.17‰). We suggest that a high LSi:BSi ratio and apparent metal oxide influence could lead to a degree of stability in the annual background benthic flux of DSi, despite current pressures on pelagic phytoplankton communities. Coupled with supporting ... |
format |
Article in Journal/Newspaper |
author |
Ward, James P.J. Hendry, Katharine R. Arndt, Sandra Faust, Johan C. Freitas, Felipe S. Henley, Sian F. Krause, Jeffrey W. März, Christian Ng, Hong Chin Pickering, Rebecca A. Tessin, Allyson C. |
spellingShingle |
Ward, James P.J. Hendry, Katharine R. Arndt, Sandra Faust, Johan C. Freitas, Felipe S. Henley, Sian F. Krause, Jeffrey W. März, Christian Ng, Hong Chin Pickering, Rebecca A. Tessin, Allyson C. Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea |
author_facet |
Ward, James P.J. Hendry, Katharine R. Arndt, Sandra Faust, Johan C. Freitas, Felipe S. Henley, Sian F. Krause, Jeffrey W. März, Christian Ng, Hong Chin Pickering, Rebecca A. Tessin, Allyson C. |
author_sort |
Ward, James P.J. |
title |
Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea |
title_short |
Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea |
title_full |
Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea |
title_fullStr |
Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea |
title_full_unstemmed |
Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea |
title_sort |
stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the arctic barents sea |
publisher |
Elsevier |
publishDate |
2022 |
url |
http://nora.nerc.ac.uk/id/eprint/532711/ https://nora.nerc.ac.uk/id/eprint/532711/1/1-s2.0-S0016703722002216-main.pdf https://www.sciencedirect.com/science/article/pii/S0016703722002216 |
geographic |
Arctic Barents Sea |
geographic_facet |
Arctic Barents Sea |
genre |
Arctic Arctic Barents Sea Phytoplankton Sea ice |
genre_facet |
Arctic Arctic Barents Sea Phytoplankton Sea ice |
op_relation |
https://nora.nerc.ac.uk/id/eprint/532711/1/1-s2.0-S0016703722002216-main.pdf Ward, James P.J.; Hendry, Katharine R. orcid:0000-0002-0790-5895 Arndt, Sandra; Faust, Johan C.; Freitas, Felipe S.; Henley, Sian F.; Krause, Jeffrey W.; März, Christian; Ng, Hong Chin; Pickering, Rebecca A.; Tessin, Allyson C. 2022 Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea. Geochimica et Cosmochimica Acta, 329. 206-230. https://doi.org/10.1016/j.gca.2022.05.005 <https://doi.org/10.1016/j.gca.2022.05.005> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.gca.2022.05.005 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
329 |
container_start_page |
206 |
op_container_end_page |
230 |
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1766301309115301888 |