Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis
International audience The silicic acid leakage hypothesis (SALH) purports that changes in silicon and nitrogen depletion ratios in the glacial Antarctic created a large pool of unused silicic acid that was transported to lower latitudes in subantarctic mode water (SAMW) where it enhanced diatom pro...
Published in: | Global Biogeochemical Cycles |
---|---|
Main Authors: | , , |
Other Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2007
|
Subjects: | |
Online Access: | https://hal.science/hal-02105680 https://hal.science/hal-02105680/document https://hal.science/hal-02105680/file/Beucher_GBC2007.pdf https://doi.org/10.1029/2006GB002746 |
id |
ftunivnantes:oai:HAL:hal-02105680v1 |
---|---|
record_format |
openpolar |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry Beucher, Charlotte Brzezinski, Mark Crosta, Xavier Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
description |
International audience The silicic acid leakage hypothesis (SALH) purports that changes in silicon and nitrogen depletion ratios in the glacial Antarctic created a large pool of unused silicic acid that was transported to lower latitudes in subantarctic mode water (SAMW) where it enhanced diatom productivity lowering atmospheric pCO 2. However, increased opal accumulation beneath the sub-Antarctic during glacial times implies significant consumption of silicic acid in subantarctic surface waters that may have significantly diminished or eliminated Si leakage. To test how nutrient dynamics in the sub-Antarctic affected the Si(OH) 4 content of SAMW during the last glacial period, we produced d 30 Si opal records for cores from the subantarctic and subtropical zones of the Indian Ocean spanning the last 50,000 years. Comparison with diatom-bound d 15 N records shows that subantarctic surface waters were enriched in Si relative to N during the last glaciation consistent with the SALH. The record from the subtropics does not show this enrichment in Si during the last glacial period suggesting that subantarctic surface waters were mainly incorporated into SAMW rather than being transported across the Subtropical Front. Isotope mass balance calculations were used to test for Si leakage from the sub-Antarctic. The results show that silicic acid concentration in SAMW would more than double during the last glaciation if upwelling and northward Ekman drift in the Antarctic were similar to the present-day circulation. Calculations that assume increased stratification in the glacial Antarctic eliminate Si leakage, but they do not produce the known increase in opal burial in the glacial sub-Antarctic. Reconciling the isotope data and opal burial records with a highly stratified Antarctic requires the addition of a large local source of silicic acid in the glacial sub-Antarctic that is inconsistent with present-day circulation and nutrient distributions. Including such a source in our calculations results in significant opal ... |
author2 |
Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Marine Science Institute Santa Barbara (MSI) University of California Santa Barbara (UC Santa Barbara) University of California (UC)-University of California (UC) UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC) Observatoire aquitain des sciences de l'univers (OASU) Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Beucher, Charlotte Brzezinski, Mark Crosta, Xavier |
author_facet |
Beucher, Charlotte Brzezinski, Mark Crosta, Xavier |
author_sort |
Beucher, Charlotte |
title |
Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis |
title_short |
Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis |
title_full |
Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis |
title_fullStr |
Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis |
title_full_unstemmed |
Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis |
title_sort |
silicic acid dynamics in the glacial sub-antarctic: implications for the silicic acid leakage hypothesis |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-02105680 https://hal.science/hal-02105680/document https://hal.science/hal-02105680/file/Beucher_GBC2007.pdf https://doi.org/10.1029/2006GB002746 |
geographic |
Antarctic Indian The Antarctic |
geographic_facet |
Antarctic Indian The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
ISSN: 0886-6236 EISSN: 1944-8224 Global Biogeochemical Cycles https://hal.science/hal-02105680 Global Biogeochemical Cycles, 2007, 21 (3), pp.GB3015. ⟨10.1029/2006GB002746⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2006GB002746 hal-02105680 https://hal.science/hal-02105680 https://hal.science/hal-02105680/document https://hal.science/hal-02105680/file/Beucher_GBC2007.pdf doi:10.1029/2006GB002746 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/2006GB002746 |
container_title |
Global Biogeochemical Cycles |
container_volume |
21 |
container_issue |
3 |
container_start_page |
n/a |
op_container_end_page |
n/a |
_version_ |
1766132343767040000 |
spelling |
ftunivnantes:oai:HAL:hal-02105680v1 2023-05-15T13:40:19+02:00 Silicic acid dynamics in the glacial sub-Antarctic: Implications for the silicic acid leakage hypothesis Beucher, Charlotte Brzezinski, Mark Crosta, Xavier Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Marine Science Institute Santa Barbara (MSI) University of California Santa Barbara (UC Santa Barbara) University of California (UC)-University of California (UC) UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC) Observatoire aquitain des sciences de l'univers (OASU) Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS) 2007 https://hal.science/hal-02105680 https://hal.science/hal-02105680/document https://hal.science/hal-02105680/file/Beucher_GBC2007.pdf https://doi.org/10.1029/2006GB002746 en eng HAL CCSD American Geophysical Union info:eu-repo/semantics/altIdentifier/doi/10.1029/2006GB002746 hal-02105680 https://hal.science/hal-02105680 https://hal.science/hal-02105680/document https://hal.science/hal-02105680/file/Beucher_GBC2007.pdf doi:10.1029/2006GB002746 info:eu-repo/semantics/OpenAccess ISSN: 0886-6236 EISSN: 1944-8224 Global Biogeochemical Cycles https://hal.science/hal-02105680 Global Biogeochemical Cycles, 2007, 21 (3), pp.GB3015. ⟨10.1029/2006GB002746⟩ [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry info:eu-repo/semantics/article Journal articles 2007 ftunivnantes https://doi.org/10.1029/2006GB002746 2023-02-08T07:43:57Z International audience The silicic acid leakage hypothesis (SALH) purports that changes in silicon and nitrogen depletion ratios in the glacial Antarctic created a large pool of unused silicic acid that was transported to lower latitudes in subantarctic mode water (SAMW) where it enhanced diatom productivity lowering atmospheric pCO 2. However, increased opal accumulation beneath the sub-Antarctic during glacial times implies significant consumption of silicic acid in subantarctic surface waters that may have significantly diminished or eliminated Si leakage. To test how nutrient dynamics in the sub-Antarctic affected the Si(OH) 4 content of SAMW during the last glacial period, we produced d 30 Si opal records for cores from the subantarctic and subtropical zones of the Indian Ocean spanning the last 50,000 years. Comparison with diatom-bound d 15 N records shows that subantarctic surface waters were enriched in Si relative to N during the last glaciation consistent with the SALH. The record from the subtropics does not show this enrichment in Si during the last glacial period suggesting that subantarctic surface waters were mainly incorporated into SAMW rather than being transported across the Subtropical Front. Isotope mass balance calculations were used to test for Si leakage from the sub-Antarctic. The results show that silicic acid concentration in SAMW would more than double during the last glaciation if upwelling and northward Ekman drift in the Antarctic were similar to the present-day circulation. Calculations that assume increased stratification in the glacial Antarctic eliminate Si leakage, but they do not produce the known increase in opal burial in the glacial sub-Antarctic. Reconciling the isotope data and opal burial records with a highly stratified Antarctic requires the addition of a large local source of silicic acid in the glacial sub-Antarctic that is inconsistent with present-day circulation and nutrient distributions. Including such a source in our calculations results in significant opal ... Article in Journal/Newspaper Antarc* Antarctic Université de Nantes: HAL-UNIV-NANTES Antarctic Indian The Antarctic Global Biogeochemical Cycles 21 3 n/a n/a |