Nitrate supply routes and impact of internal cycling in the North Atlantic Ocean inferred from nitrate isotopic composition
Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 35(4), (2021): e2020GB006887, https://doi.org/10.1029/2020GB00688...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/27357 2023-05-15T17:25:20+02:00 Nitrate supply routes and impact of internal cycling in the North Atlantic Ocean inferred from nitrate isotopic composition Deman, Florian Fonseca-Batista, Debany Roukaerts, Arnout García-Ibáñez, Maribel I. Le Roy, Emilie Thilakarathne, E. P. D. N. Elskens, Marc Dehairs, Frank Fripiat, Francois 2021-04-02 https://hdl.handle.net/1912/27357 unknown American Geophysical Union https://doi.org/10.1029/2020GB006887 Deman, F., Fonseca-Batista, D., Roukaerts, A., Garcia-Ibanez, M. I., Le Roy, E., Thilakarathne, E. P. D. N., Elskens, M., Dehairs, F., & Fripiat, F. (2021). Nitrate supply routes and impact of internal cycling in the North Atlantic Ocean inferred from nitrate isotopic composition. Global Biogeochemical Cycles, 35(4), e2020GB006887. https://hdl.handle.net/1912/27357 doi:10.1029/2020GB006887 Deman, F., Fonseca-Batista, D., Roukaerts, A., Garcia-Ibanez, M. I., Le Roy, E., Thilakarathne, E. P. D. N., Elskens, M., Dehairs, F., & Fripiat, F. (2021). Nitrate supply routes and impact of internal cycling in the North Atlantic Ocean inferred from nitrate isotopic composition. Global Biogeochemical Cycles, 35(4), e2020GB006887. doi:10.1029/2020GB006887 Atlantic Isotopy Nitrate Article 2021 ftwhoas https://doi.org/10.1029/2020GB006887 2022-10-29T22:57:24Z Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 35(4), (2021): e2020GB006887, https://doi.org/10.1029/2020GB006887. In this study we report full-depth water column profiles for nitrogen and oxygen isotopic composition (δ15N and δ18O) of nitrate (NO3−) 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 NO3− δ15N and δ18O shows that assimilation by phytoplankton is the main process controlling the NO3− isotopic composition in the upper 150 m, with values increasing in a NO3− δ18O versus δ15N space along a line with a slope of one toward the surface. In the subpolar gyre, a single relationship between the degree of NO3− consumption and residual NO3− δ15N supports the view that NO3− 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 NO3− assimilation and nitrification in the deep mixed layer of the subpolar gyre elevates subsurface NO3− δ18O 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 NO3− δ18O toward the δ18O of regenerated NO3−. The low NO3− δ15N observed south of the Subarctic Front is mostly explained by N2 fixation, although a contribution from the Mediterranean outflow is required to explain the lower NO3− δ15N signal observed between 600 and 1500 m depth close to the Iberian margin. The GEOVIDE project was co-funded by the French national program LEFE/INSU (GEOVIDE), ANR Blanc (GEOVIDE) and RPDOC, LabEX MER and ... Article in Journal/Newspaper north atlantic current North Atlantic Subarctic Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Global Biogeochemical Cycles 35 4 |
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Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
unknown |
topic |
Atlantic Isotopy Nitrate |
spellingShingle |
Atlantic Isotopy Nitrate Deman, Florian Fonseca-Batista, Debany Roukaerts, Arnout García-Ibáñez, Maribel I. Le Roy, Emilie Thilakarathne, E. P. D. N. Elskens, Marc Dehairs, Frank Fripiat, Francois Nitrate supply routes and impact of internal cycling in the North Atlantic Ocean inferred from nitrate isotopic composition |
topic_facet |
Atlantic Isotopy Nitrate |
description |
Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 35(4), (2021): e2020GB006887, https://doi.org/10.1029/2020GB006887. In this study we report full-depth water column profiles for nitrogen and oxygen isotopic composition (δ15N and δ18O) of nitrate (NO3−) 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 NO3− δ15N and δ18O shows that assimilation by phytoplankton is the main process controlling the NO3− isotopic composition in the upper 150 m, with values increasing in a NO3− δ18O versus δ15N space along a line with a slope of one toward the surface. In the subpolar gyre, a single relationship between the degree of NO3− consumption and residual NO3− δ15N supports the view that NO3− 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 NO3− assimilation and nitrification in the deep mixed layer of the subpolar gyre elevates subsurface NO3− δ18O 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 NO3− δ18O toward the δ18O of regenerated NO3−. The low NO3− δ15N observed south of the Subarctic Front is mostly explained by N2 fixation, although a contribution from the Mediterranean outflow is required to explain the lower NO3− δ15N signal observed between 600 and 1500 m depth close to the Iberian margin. The GEOVIDE project was co-funded by the French national program LEFE/INSU (GEOVIDE), ANR Blanc (GEOVIDE) and RPDOC, LabEX MER and ... |
format |
Article in Journal/Newspaper |
author |
Deman, Florian Fonseca-Batista, Debany Roukaerts, Arnout García-Ibáñez, Maribel I. Le Roy, Emilie Thilakarathne, E. P. D. N. Elskens, Marc Dehairs, Frank Fripiat, Francois |
author_facet |
Deman, Florian Fonseca-Batista, Debany Roukaerts, Arnout García-Ibáñez, Maribel I. Le Roy, Emilie Thilakarathne, E. P. D. N. Elskens, Marc Dehairs, Frank Fripiat, Francois |
author_sort |
Deman, Florian |
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 |
American Geophysical Union |
publishDate |
2021 |
url |
https://hdl.handle.net/1912/27357 |
genre |
north atlantic current North Atlantic Subarctic |
genre_facet |
north atlantic current North Atlantic Subarctic |
op_source |
Deman, F., Fonseca-Batista, D., Roukaerts, A., Garcia-Ibanez, M. I., Le Roy, E., Thilakarathne, E. P. D. N., Elskens, M., Dehairs, F., & Fripiat, F. (2021). Nitrate supply routes and impact of internal cycling in the North Atlantic Ocean inferred from nitrate isotopic composition. Global Biogeochemical Cycles, 35(4), e2020GB006887. doi:10.1029/2020GB006887 |
op_relation |
https://doi.org/10.1029/2020GB006887 Deman, F., Fonseca-Batista, D., Roukaerts, A., Garcia-Ibanez, M. I., Le Roy, E., Thilakarathne, E. P. D. N., Elskens, M., Dehairs, F., & Fripiat, F. (2021). Nitrate supply routes and impact of internal cycling in the North Atlantic Ocean inferred from nitrate isotopic composition. Global Biogeochemical Cycles, 35(4), e2020GB006887. https://hdl.handle.net/1912/27357 doi:10.1029/2020GB006887 |
op_doi |
https://doi.org/10.1029/2020GB006887 |
container_title |
Global Biogeochemical Cycles |
container_volume |
35 |
container_issue |
4 |
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1766116737890123776 |