Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean
[1] The fractionation of silicon (Si) stable isotopes by biological activity in the surface ocean makes the stable isotope composition of silicon (d 30 Si) dissolved in seawater a sensitive tracer of the oceanic biogeochemical Si cycle. We present a high-precision dataset that characterizes the d 30...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.405.9325 2023-05-15T14:01:15+02:00 Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean Gregory F. De Souza Ben C. Reynolds Jörg Rickli Martin Frank Mak A. Saito Loes J. A. Gerringa Bernard Bourdon The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.9325 http://hal-ens-lyon.archives-ouvertes.fr/docs/00/72/11/35/PDF/2011GB004141.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.9325 http://hal-ens-lyon.archives-ouvertes.fr/docs/00/72/11/35/PDF/2011GB004141.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://hal-ens-lyon.archives-ouvertes.fr/docs/00/72/11/35/PDF/2011GB004141.pdf text ftciteseerx 2016-01-08T03:03:12Z [1] The fractionation of silicon (Si) stable isotopes by biological activity in the surface ocean makes the stable isotope composition of silicon (d 30 Si) dissolved in seawater a sensitive tracer of the oceanic biogeochemical Si cycle. We present a high-precision dataset that characterizes the d 30 Si distribution in the deep Atlantic Ocean from Denmark Strait to Drake Passage, documenting strong meridional and smaller, but resolvable, vertical d 30 Si gradients. We show that these gradients are related to the two sources of deep and bottom waters in the Atlantic Ocean: waters of North Atlantic and Nordic origin carry a high d 30 Si signature of ≥+1.7 ‰ into the deep Atlantic, while Antarctic Bottom Water transports Si with a low d 30 Si value of around +1.2‰. The deep Atlantic d 30 Si distribution is thus governed by the quasi-conservative mixing of Si from these two isotopically distinct sources. This disparity in Si isotope composition between the North Atlantic and Southern Ocean is in marked contrast to the homogeneity of the stable nitrogen isotope composition of deep ocean nitrate (d 15 N-NO 3). We infer that the meridional d 30 Si gradient derives from the transport of the high d 30 Si signature of Southern Ocean intermediate/mode waters into the North Atlantic by the upper return path of the meridional overturning circulation (MOC). The basin-scale deep Atlantic d 30 Si gradient thus owes its existence to the interaction of the physical circulation with biological nutrient uptake at high southern latitudes, which fractionates Si isotopes between the abyssal and intermediate/mode waters formed in the Southern Ocean. Text Antarc* Antarctic Denmark Strait Drake Passage North Atlantic Southern Ocean Unknown Antarctic Drake Passage Southern Ocean |
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English |
description |
[1] The fractionation of silicon (Si) stable isotopes by biological activity in the surface ocean makes the stable isotope composition of silicon (d 30 Si) dissolved in seawater a sensitive tracer of the oceanic biogeochemical Si cycle. We present a high-precision dataset that characterizes the d 30 Si distribution in the deep Atlantic Ocean from Denmark Strait to Drake Passage, documenting strong meridional and smaller, but resolvable, vertical d 30 Si gradients. We show that these gradients are related to the two sources of deep and bottom waters in the Atlantic Ocean: waters of North Atlantic and Nordic origin carry a high d 30 Si signature of ≥+1.7 ‰ into the deep Atlantic, while Antarctic Bottom Water transports Si with a low d 30 Si value of around +1.2‰. The deep Atlantic d 30 Si distribution is thus governed by the quasi-conservative mixing of Si from these two isotopically distinct sources. This disparity in Si isotope composition between the North Atlantic and Southern Ocean is in marked contrast to the homogeneity of the stable nitrogen isotope composition of deep ocean nitrate (d 15 N-NO 3). We infer that the meridional d 30 Si gradient derives from the transport of the high d 30 Si signature of Southern Ocean intermediate/mode waters into the North Atlantic by the upper return path of the meridional overturning circulation (MOC). The basin-scale deep Atlantic d 30 Si gradient thus owes its existence to the interaction of the physical circulation with biological nutrient uptake at high southern latitudes, which fractionates Si isotopes between the abyssal and intermediate/mode waters formed in the Southern Ocean. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Gregory F. De Souza Ben C. Reynolds Jörg Rickli Martin Frank Mak A. Saito Loes J. A. Gerringa Bernard Bourdon |
spellingShingle |
Gregory F. De Souza Ben C. Reynolds Jörg Rickli Martin Frank Mak A. Saito Loes J. A. Gerringa Bernard Bourdon Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean |
author_facet |
Gregory F. De Souza Ben C. Reynolds Jörg Rickli Martin Frank Mak A. Saito Loes J. A. Gerringa Bernard Bourdon |
author_sort |
Gregory F. De Souza |
title |
Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean |
title_short |
Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean |
title_full |
Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean |
title_fullStr |
Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean |
title_full_unstemmed |
Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean |
title_sort |
southern ocean control of silicon stable isotope distribution in the deep atlantic ocean |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.9325 http://hal-ens-lyon.archives-ouvertes.fr/docs/00/72/11/35/PDF/2011GB004141.pdf |
geographic |
Antarctic Drake Passage Southern Ocean |
geographic_facet |
Antarctic Drake Passage Southern Ocean |
genre |
Antarc* Antarctic Denmark Strait Drake Passage North Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctic Denmark Strait Drake Passage North Atlantic Southern Ocean |
op_source |
http://hal-ens-lyon.archives-ouvertes.fr/docs/00/72/11/35/PDF/2011GB004141.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.405.9325 http://hal-ens-lyon.archives-ouvertes.fr/docs/00/72/11/35/PDF/2011GB004141.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
_version_ |
1766270840852185088 |