Nitrate Supply Routes and Impact of Internal Cycling in the North Atlantic Ocean Inferred From Nitrate Isotopic Composition
Abstract In this study we report full‐depth water column profiles for nitrogen and oxygen isotopic composition (δ 15 N and δ 18 O) of nitrate (NO 3 − ) during the GEOTRACES GA01 cruise (2014). This transect intersects the double gyre system of the subtropical and subpolar regions of the North Atlant...
Published in: | Global Biogeochemical Cycles |
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Main Authors: | , , , , , , , , |
Other Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2021
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Online Access: | https://hal.science/hal-04211593 https://hal.science/hal-04211593/document https://hal.science/hal-04211593/file/Global%20Biogeochemical%20Cycles%20-%202021%20-%20Deman%20-%20Nitrate%20Supply%20Routes%20and%20Impact%20of%20Internal%20Cycling%20in%20the%20North%20Atlantic.pdf https://doi.org/10.1029/2020GB006887 |
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Open Polar |
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Institut national des sciences de l'Univers: HAL-INSU |
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ftinsu |
language |
English |
topic |
Atlantic isotopy nitrate [SDE]Environmental Sciences [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
Atlantic isotopy nitrate [SDE]Environmental Sciences [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Deman, F. Fonseca-Batista, D. Roukaerts, A. García-Ibáñez, M. Le Roy, E. Thilakarathne, E. Elskens, M. Dehairs, F. Fripiat, F. Nitrate Supply Routes and Impact of Internal Cycling in the North Atlantic Ocean Inferred From Nitrate Isotopic Composition |
topic_facet |
Atlantic isotopy nitrate [SDE]Environmental Sciences [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
Abstract In this study we report full‐depth water column profiles for nitrogen and oxygen isotopic composition (δ 15 N and δ 18 O) of nitrate (NO 3 − ) during the GEOTRACES GA01 cruise (2014). This transect intersects the double gyre system of the subtropical and subpolar regions of the North Atlantic separated by a strong transition zone, the North Atlantic Current. The distribution of NO 3 − δ 15 N and δ 18 O shows that assimilation by phytoplankton is the main process controlling the NO 3 − isotopic composition in the upper 150 m, with values increasing in a NO 3 − δ 18 O versus δ 15 N space along a line with a slope of one toward the surface. In the subpolar gyre, a single relationship between the degree of NO 3 − consumption and residual NO 3 − δ 15 N supports the view that NO 3 − is supplied via Ekman upwelling and deep winter convection, and progressively consumed during the Ekman transport of surface water southward. The co‐occurrence of partial NO 3 − assimilation and nitrification in the deep mixed layer of the subpolar gyre elevates subsurface NO 3 − δ 18 O in comparison to deep oceanic values. This signal propagates through isopycnal exchanges to greater depths at lower latitudes. With recirculation in the subtropical gyre, cycles of quantitative consumption‐nitrification progressively decrease subsurface NO 3 − δ 18 O toward the δ 18 O of regenerated NO 3 − . The low NO 3 − δ 15 N observed south of the Subarctic Front is mostly explained by N 2 fixation, although a contribution from the Mediterranean outflow is required to explain the lower NO 3 − δ 15 N signal observed between 600 and 1500 m depth close to the Iberian margin. |
author2 |
Vrije Universiteit Brussel (VUB) Analytical, Environmental and Geo- Chemistry Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Analytical and Environmental Chemistry and Earth System Sciences ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017) |
format |
Article in Journal/Newspaper |
author |
Deman, F. Fonseca-Batista, D. Roukaerts, A. García-Ibáñez, M. Le Roy, E. Thilakarathne, E. Elskens, M. Dehairs, F. Fripiat, F. |
author_facet |
Deman, F. Fonseca-Batista, D. Roukaerts, A. García-Ibáñez, M. Le Roy, E. Thilakarathne, E. Elskens, M. Dehairs, F. Fripiat, F. |
author_sort |
Deman, F. |
title |
Nitrate Supply Routes and Impact of Internal Cycling in the North Atlantic Ocean Inferred From Nitrate Isotopic Composition |
title_short |
Nitrate Supply Routes and Impact of Internal Cycling in the North Atlantic Ocean Inferred From Nitrate Isotopic Composition |
title_full |
Nitrate Supply Routes and Impact of Internal Cycling in the North Atlantic Ocean Inferred From Nitrate Isotopic Composition |
title_fullStr |
Nitrate Supply Routes and Impact of Internal Cycling in the North Atlantic Ocean Inferred From Nitrate Isotopic Composition |
title_full_unstemmed |
Nitrate Supply Routes and Impact of Internal Cycling in the North Atlantic Ocean Inferred From Nitrate Isotopic Composition |
title_sort |
nitrate supply routes and impact of internal cycling in the north atlantic ocean inferred from nitrate isotopic composition |
publisher |
HAL CCSD |
publishDate |
2021 |
url |
https://hal.science/hal-04211593 https://hal.science/hal-04211593/document https://hal.science/hal-04211593/file/Global%20Biogeochemical%20Cycles%20-%202021%20-%20Deman%20-%20Nitrate%20Supply%20Routes%20and%20Impact%20of%20Internal%20Cycling%20in%20the%20North%20Atlantic.pdf https://doi.org/10.1029/2020GB006887 |
genre |
north atlantic current North Atlantic Subarctic |
genre_facet |
north atlantic current North Atlantic Subarctic |
op_source |
ISSN: 0886-6236 EISSN: 1944-8224 Global Biogeochemical Cycles https://hal.science/hal-04211593 Global Biogeochemical Cycles, 2021, 35 (4), ⟨10.1029/2020GB006887⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2020GB006887 hal-04211593 https://hal.science/hal-04211593 https://hal.science/hal-04211593/document https://hal.science/hal-04211593/file/Global%20Biogeochemical%20Cycles%20-%202021%20-%20Deman%20-%20Nitrate%20Supply%20Routes%20and%20Impact%20of%20Internal%20Cycling%20in%20the%20North%20Atlantic.pdf doi:10.1029/2020GB006887 |
op_rights |
http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/2020GB006887 |
container_title |
Global Biogeochemical Cycles |
container_volume |
35 |
container_issue |
4 |
_version_ |
1787426389522120704 |
spelling |
ftinsu:oai:HAL:hal-04211593v1 2024-01-07T09:44:57+01:00 Nitrate Supply Routes and Impact of Internal Cycling in the North Atlantic Ocean Inferred From Nitrate Isotopic Composition Deman, F. Fonseca-Batista, D. Roukaerts, A. García-Ibáñez, M. Le Roy, E. Thilakarathne, E. Elskens, M. Dehairs, F. Fripiat, F. Vrije Universiteit Brussel (VUB) Analytical, Environmental and Geo- Chemistry Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Analytical and Environmental Chemistry and Earth System Sciences ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017) 2021-04 https://hal.science/hal-04211593 https://hal.science/hal-04211593/document https://hal.science/hal-04211593/file/Global%20Biogeochemical%20Cycles%20-%202021%20-%20Deman%20-%20Nitrate%20Supply%20Routes%20and%20Impact%20of%20Internal%20Cycling%20in%20the%20North%20Atlantic.pdf https://doi.org/10.1029/2020GB006887 en eng HAL CCSD American Geophysical Union info:eu-repo/semantics/altIdentifier/doi/10.1029/2020GB006887 hal-04211593 https://hal.science/hal-04211593 https://hal.science/hal-04211593/document https://hal.science/hal-04211593/file/Global%20Biogeochemical%20Cycles%20-%202021%20-%20Deman%20-%20Nitrate%20Supply%20Routes%20and%20Impact%20of%20Internal%20Cycling%20in%20the%20North%20Atlantic.pdf doi:10.1029/2020GB006887 http://hal.archives-ouvertes.fr/licences/copyright/ info:eu-repo/semantics/OpenAccess ISSN: 0886-6236 EISSN: 1944-8224 Global Biogeochemical Cycles https://hal.science/hal-04211593 Global Biogeochemical Cycles, 2021, 35 (4), ⟨10.1029/2020GB006887⟩ Atlantic isotopy nitrate [SDE]Environmental Sciences [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2021 ftinsu https://doi.org/10.1029/2020GB006887 2023-12-13T17:22:40Z Abstract In this study we report full‐depth water column profiles for nitrogen and oxygen isotopic composition (δ 15 N and δ 18 O) of nitrate (NO 3 − ) during the GEOTRACES GA01 cruise (2014). This transect intersects the double gyre system of the subtropical and subpolar regions of the North Atlantic separated by a strong transition zone, the North Atlantic Current. The distribution of NO 3 − δ 15 N and δ 18 O shows that assimilation by phytoplankton is the main process controlling the NO 3 − isotopic composition in the upper 150 m, with values increasing in a NO 3 − δ 18 O versus δ 15 N space along a line with a slope of one toward the surface. In the subpolar gyre, a single relationship between the degree of NO 3 − consumption and residual NO 3 − δ 15 N supports the view that NO 3 − is supplied via Ekman upwelling and deep winter convection, and progressively consumed during the Ekman transport of surface water southward. The co‐occurrence of partial NO 3 − assimilation and nitrification in the deep mixed layer of the subpolar gyre elevates subsurface NO 3 − δ 18 O in comparison to deep oceanic values. This signal propagates through isopycnal exchanges to greater depths at lower latitudes. With recirculation in the subtropical gyre, cycles of quantitative consumption‐nitrification progressively decrease subsurface NO 3 − δ 18 O toward the δ 18 O of regenerated NO 3 − . The low NO 3 − δ 15 N observed south of the Subarctic Front is mostly explained by N 2 fixation, although a contribution from the Mediterranean outflow is required to explain the lower NO 3 − δ 15 N signal observed between 600 and 1500 m depth close to the Iberian margin. Article in Journal/Newspaper north atlantic current North Atlantic Subarctic Institut national des sciences de l'Univers: HAL-INSU Global Biogeochemical Cycles 35 4 |