Withdrawn : Observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic North Atlantic
Sustaining biological export over the open ocean requires a compensating physical supply of nutrients to the euphotic zone. The relative importance of diapycnal mixing and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in some of the most...
Published in: | Global Biogeochemical Cycles |
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Format: | Article in Journal/Newspaper |
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2021
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Online Access: | https://hal.science/hal-04203496 https://doi.org/10.1029/2021GB006971 |
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ftccsdartic:oai:HAL:hal-04203496v1 2023-12-17T10:46:22+01:00 Withdrawn : Observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic North Atlantic Spingys, Carl P. Williams, Richard G. Tuerena, Robyn E. Garabato, Alberto Naveira Vic, Clement Forryan, Alexander Sharples, Jonathan University of Liverpool National Oceanography Centre (NOC) Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) 2021 https://hal.science/hal-04203496 https://doi.org/10.1029/2021GB006971 en eng HAL CCSD American Geophysical Union info:eu-repo/semantics/altIdentifier/doi/10.1029/2021GB006971 hal-04203496 https://hal.science/hal-04203496 doi:10.1029/2021GB006971 ISSN: 0886-6236 EISSN: 1944-8224 Global Biogeochemical Cycles https://hal.science/hal-04203496 Global Biogeochemical Cycles, 2021, 35 (8), e2021GB006971 (1p.). ⟨10.1029/2021GB006971⟩ [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2021 ftccsdartic https://doi.org/10.1029/2021GB006971 2023-11-18T23:44:07Z Sustaining biological export over the open ocean requires a compensating physical supply of nutrients to the euphotic zone. The relative importance of diapycnal mixing and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in some of the most oligotrophic waters in the subtropical North Atlantic, using transects over and off the mid-Atlantic ridge. Eddy stirring rates are estimated, firstly, from the excess temperature variance dissipation relative to the turbulent kinetic energy dissipation and, secondly, using eddy statistics from satellite observations combined with 9-month-long mooring data. The vertical nutrient fluxes by diapycnal mixing and isopycnal mesoscale eddy stirring are assessed using nitrate measurements from observations or a climatology. The diapycnal transfer provides a nutrient supply within the euphotic zone, but induces a loss of nutrients within the upper thermocline. Eddy stirring augments, and is comparable to, the diapycnal transfer of nutrients within the summertime upper thermocline, while also acting to replenish nutrients within the deeper parts of the thermocline. The eddy supply of nitrate is relatively small in the centre of the subtropical gyre, reaching up to 0.06 mol N m−2yr−1, but is likely to be enhanced on the flanks of the gyre due to larger isopycnal slopes and lateral nitrate gradients. The nutrient supply to the euphotic zone is achieved via a multi-stage mechanism: a diapycnal transfer of nutrients by small-scale turbulence to the euphotic zone and an isopycnal stirring of nutrients by mesoscale eddies replenishing nutrients in the upper thermocline.Plain Language SummaryPhytoplankton growth requires a supply of nutrients to the base of the euphotic zone, which is usually provided by a combination of vertical mixing or vertical upwelling of nutrients. However, in the oligotrophic waters of the central North Atlantic, it is unclear how the vertical supply of nutrients is sustained. Here we use field data to ... Article in Journal/Newspaper North Atlantic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Mid-Atlantic Ridge Global Biogeochemical Cycles 35 8 |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU]Sciences of the Universe [physics] |
spellingShingle |
[SDU]Sciences of the Universe [physics] Spingys, Carl P. Williams, Richard G. Tuerena, Robyn E. Garabato, Alberto Naveira Vic, Clement Forryan, Alexander Sharples, Jonathan Withdrawn : Observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic North Atlantic |
topic_facet |
[SDU]Sciences of the Universe [physics] |
description |
Sustaining biological export over the open ocean requires a compensating physical supply of nutrients to the euphotic zone. The relative importance of diapycnal mixing and isopycnal stirring by mesoscale eddies in providing this nutrient supply is explored using a field campaign in some of the most oligotrophic waters in the subtropical North Atlantic, using transects over and off the mid-Atlantic ridge. Eddy stirring rates are estimated, firstly, from the excess temperature variance dissipation relative to the turbulent kinetic energy dissipation and, secondly, using eddy statistics from satellite observations combined with 9-month-long mooring data. The vertical nutrient fluxes by diapycnal mixing and isopycnal mesoscale eddy stirring are assessed using nitrate measurements from observations or a climatology. The diapycnal transfer provides a nutrient supply within the euphotic zone, but induces a loss of nutrients within the upper thermocline. Eddy stirring augments, and is comparable to, the diapycnal transfer of nutrients within the summertime upper thermocline, while also acting to replenish nutrients within the deeper parts of the thermocline. The eddy supply of nitrate is relatively small in the centre of the subtropical gyre, reaching up to 0.06 mol N m−2yr−1, but is likely to be enhanced on the flanks of the gyre due to larger isopycnal slopes and lateral nitrate gradients. The nutrient supply to the euphotic zone is achieved via a multi-stage mechanism: a diapycnal transfer of nutrients by small-scale turbulence to the euphotic zone and an isopycnal stirring of nutrients by mesoscale eddies replenishing nutrients in the upper thermocline.Plain Language SummaryPhytoplankton growth requires a supply of nutrients to the base of the euphotic zone, which is usually provided by a combination of vertical mixing or vertical upwelling of nutrients. However, in the oligotrophic waters of the central North Atlantic, it is unclear how the vertical supply of nutrients is sustained. Here we use field data to ... |
author2 |
University of Liverpool National Oceanography Centre (NOC) Laboratoire d'Océanographie Physique et Spatiale (LOPS) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Spingys, Carl P. Williams, Richard G. Tuerena, Robyn E. Garabato, Alberto Naveira Vic, Clement Forryan, Alexander Sharples, Jonathan |
author_facet |
Spingys, Carl P. Williams, Richard G. Tuerena, Robyn E. Garabato, Alberto Naveira Vic, Clement Forryan, Alexander Sharples, Jonathan |
author_sort |
Spingys, Carl P. |
title |
Withdrawn : Observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic North Atlantic |
title_short |
Withdrawn : Observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic North Atlantic |
title_full |
Withdrawn : Observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic North Atlantic |
title_fullStr |
Withdrawn : Observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic North Atlantic |
title_full_unstemmed |
Withdrawn : Observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic North Atlantic |
title_sort |
withdrawn : observations of nutrient supply by mesoscale eddy stirring and diapycnal mixing in the oligotrophic north atlantic |
publisher |
HAL CCSD |
publishDate |
2021 |
url |
https://hal.science/hal-04203496 https://doi.org/10.1029/2021GB006971 |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 0886-6236 EISSN: 1944-8224 Global Biogeochemical Cycles https://hal.science/hal-04203496 Global Biogeochemical Cycles, 2021, 35 (8), e2021GB006971 (1p.). ⟨10.1029/2021GB006971⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2021GB006971 hal-04203496 https://hal.science/hal-04203496 doi:10.1029/2021GB006971 |
op_doi |
https://doi.org/10.1029/2021GB006971 |
container_title |
Global Biogeochemical Cycles |
container_volume |
35 |
container_issue |
8 |
_version_ |
1785569811523174400 |