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...
Main Authors: | , , , , , , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2022
|
Subjects: | |
Online Access: | http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/346940 https://dipot.ulb.ac.be/dspace/bitstream/2013/346940/1/doi_330584.pdf |
id |
ftunivbruxelles:oai:dipot.ulb.ac.be:2013/346940 |
---|---|
record_format |
openpolar |
spelling |
ftunivbruxelles:oai:dipot.ulb.ac.be:2013/346940 2023-05-15T15:17:19+02:00 Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea Ward, James Hendry, Katharine K.R. Arndt, Sandra Faust, Johan J.C. Freitas, Felipe F.S. Henley, Sian S.F. Krause, Jeffrey J.W. März, Christian Ng, Hong Chin Pickering, Rebecca R.A. Tessin, Allyson A.C. 2022-07 1 full-text file(s): application/pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/346940 https://dipot.ulb.ac.be/dspace/bitstream/2013/346940/1/doi_330584.pdf en eng uri/info:doi/10.1016/j.gca.2022.05.005 uri/info:pii/S0016703722002216 uri/info:scp/85131807091 https://dipot.ulb.ac.be/dspace/bitstream/2013/346940/1/doi_330584.pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/346940 1 full-text file(s): info:eu-repo/semantics/openAccess Geochimica et cosmochimica acta, 329 Géochimie Pétrologie Benthic flux Pore water Reactive pools Sediment nutrient cycling Silicon isotopes info:eu-repo/semantics/article info:ulb-repo/semantics/articlePeerReview info:ulb-repo/semantics/openurl/article 2022 ftunivbruxelles 2022-08-10T22:20:49Z 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 (δ30Si) 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 μmol g dry wt−1) drive correspondingly low asymptotic concentrations of pore water DSi of ∼100 μM, relative to biosiliceous sediments (>20 wt% BSi) wherein DSi can reach ∼900 μM. 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 μM, 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 δ30Si 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 ... Article in Journal/Newspaper Arctic Barents Sea Phytoplankton Sea ice DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) Arctic Barents Sea |
institution |
Open Polar |
collection |
DI-fusion : dépôt institutionnel de l'Université libre de Bruxelles (ULB) |
op_collection_id |
ftunivbruxelles |
language |
English |
topic |
Géochimie Pétrologie Benthic flux Pore water Reactive pools Sediment nutrient cycling Silicon isotopes |
spellingShingle |
Géochimie Pétrologie Benthic flux Pore water Reactive pools Sediment nutrient cycling Silicon isotopes Ward, James Hendry, Katharine K.R. Arndt, Sandra Faust, Johan J.C. Freitas, Felipe F.S. Henley, Sian S.F. Krause, Jeffrey J.W. März, Christian Ng, Hong Chin Pickering, Rebecca R.A. Tessin, Allyson A.C. Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea |
topic_facet |
Géochimie Pétrologie Benthic flux Pore water Reactive pools Sediment nutrient cycling Silicon isotopes |
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 (δ30Si) 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 μmol g dry wt−1) drive correspondingly low asymptotic concentrations of pore water DSi of ∼100 μM, relative to biosiliceous sediments (>20 wt% BSi) wherein DSi can reach ∼900 μM. 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 μM, 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 δ30Si 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 ... |
format |
Article in Journal/Newspaper |
author |
Ward, James Hendry, Katharine K.R. Arndt, Sandra Faust, Johan J.C. Freitas, Felipe F.S. Henley, Sian S.F. Krause, Jeffrey J.W. März, Christian Ng, Hong Chin Pickering, Rebecca R.A. Tessin, Allyson A.C. |
author_facet |
Ward, James Hendry, Katharine K.R. Arndt, Sandra Faust, Johan J.C. Freitas, Felipe F.S. Henley, Sian S.F. Krause, Jeffrey J.W. März, Christian Ng, Hong Chin Pickering, Rebecca R.A. Tessin, Allyson A.C. |
author_sort |
Ward, James |
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 |
publishDate |
2022 |
url |
http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/346940 https://dipot.ulb.ac.be/dspace/bitstream/2013/346940/1/doi_330584.pdf |
geographic |
Arctic Barents Sea |
geographic_facet |
Arctic Barents Sea |
genre |
Arctic Barents Sea Phytoplankton Sea ice |
genre_facet |
Arctic Barents Sea Phytoplankton Sea ice |
op_source |
Geochimica et cosmochimica acta, 329 |
op_relation |
uri/info:doi/10.1016/j.gca.2022.05.005 uri/info:pii/S0016703722002216 uri/info:scp/85131807091 https://dipot.ulb.ac.be/dspace/bitstream/2013/346940/1/doi_330584.pdf http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/346940 |
op_rights |
1 full-text file(s): info:eu-repo/semantics/openAccess |
_version_ |
1766347561891790848 |