Autonomous profiling float observations of the high-biomass plume downstream of the Kerguelen Plateau in the Southern Ocean
International audience Natural iron fertilisation from Southern Ocean islands results in high primary production and phytoplankton biomass accumulations readily visible in satellite ocean colour observations. These images reveal great spatial complexity with highly varying concentrations of chloroph...
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2015
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Online Access: | https://hal.science/hal-04115140 https://doi.org/10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 |
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ftccsdartic:oai:HAL:hal-04115140v1 |
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Open Polar |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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language |
English |
topic |
Earth Science [SDU]Sciences of the Universe [physics] |
spellingShingle |
Earth Science [SDU]Sciences of the Universe [physics] Grenier, M. Della Penna, A. Trull, T. W. Autonomous profiling float observations of the high-biomass plume downstream of the Kerguelen Plateau in the Southern Ocean |
topic_facet |
Earth Science [SDU]Sciences of the Universe [physics] |
description |
International audience Natural iron fertilisation from Southern Ocean islands results in high primary production and phytoplankton biomass accumulations readily visible in satellite ocean colour observations. These images reveal great spatial complexity with highly varying concentrations of chlorophyll, presumably reflecting both variations in iron supply and conditions favouring phytoplankton accumulation. To examine the second aspect, in particular the influences of variations in temperature and mixed layer depth, we deployed four autonomous profiling floats in the Antarctic Circumpolar Current near the Kerguelen Plateau in the Indian sector of the Southern Ocean. Each "bio-profiler" measured more than 250 profiles of temperature (T), salinity (S), dissolved oxygen, chlorophyll a (Chl a) fluorescence, and particulate backscattering (b bp ) in the top 300 m of the water column, sampling up to 5 profiles per day along meandering trajectories extending up to 1000 km. Comparison of surface Chl a estimates (analogous to values from satellite images) with total water column inventories revealed largely linear relationships, suggesting that these images provide credible information on total and not just surface biomass spatial distributions. However, they also showed that physical mixed layer depths are often not a reliable guide to biomass distributions. Regions of very high Chl a accumulation (1.5-10 μg L -1 ) were associated predominantly with a narrow T-S class of surface waters. In contrast, waters with only moderate Chl a enrichments (0.5-1.5 μg L -1 ) displayed no clear correlation with specific water properties, including no dependence on mixed layer depth or the intensity of stratification. Geostrophic trajectory analysis suggests that both these observations can be explained if the main determinant of biomass in a given water parcel is the time since leaving the Kerguelen Plateau. One float became trapped in a cyclonic eddy, allowing temporal evaluation of the water column in early autumn. During this ... |
author2 |
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) Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Grenier, M. Della Penna, A. Trull, T. W. |
author_facet |
Grenier, M. Della Penna, A. Trull, T. W. |
author_sort |
Grenier, M. |
title |
Autonomous profiling float observations of the high-biomass plume downstream of the Kerguelen Plateau in the Southern Ocean |
title_short |
Autonomous profiling float observations of the high-biomass plume downstream of the Kerguelen Plateau in the Southern Ocean |
title_full |
Autonomous profiling float observations of the high-biomass plume downstream of the Kerguelen Plateau in the Southern Ocean |
title_fullStr |
Autonomous profiling float observations of the high-biomass plume downstream of the Kerguelen Plateau in the Southern Ocean |
title_full_unstemmed |
Autonomous profiling float observations of the high-biomass plume downstream of the Kerguelen Plateau in the Southern Ocean |
title_sort |
autonomous profiling float observations of the high-biomass plume downstream of the kerguelen plateau in the southern ocean |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://hal.science/hal-04115140 https://doi.org/10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 |
geographic |
Antarctic Southern Ocean The Antarctic Kerguelen Indian |
geographic_facet |
Antarctic Southern Ocean The Antarctic Kerguelen Indian |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Biogeosciences https://hal.science/hal-04115140 Biogeosciences, 2015, 12, pp.2707-2735. ⟨10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 hal-04115140 https://hal.science/hal-04115140 BIBCODE: 2015BGeo.12.2707G doi:10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 |
op_doi |
https://doi.org/10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 |
_version_ |
1769010259302547456 |
spelling |
ftccsdartic:oai:HAL:hal-04115140v1 2023-06-18T03:37:26+02:00 Autonomous profiling float observations of the high-biomass plume downstream of the Kerguelen Plateau in the Southern Ocean Grenier, M. Della Penna, A. Trull, T. W. 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) Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) 2015 https://hal.science/hal-04115140 https://doi.org/10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 hal-04115140 https://hal.science/hal-04115140 BIBCODE: 2015BGeo.12.2707G doi:10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 Biogeosciences https://hal.science/hal-04115140 Biogeosciences, 2015, 12, pp.2707-2735. ⟨10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014⟩ Earth Science [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2015 ftccsdartic https://doi.org/10.5194/bg-12-2707-201510.5194/bgd-11-17413-2014 2023-06-03T23:49:37Z International audience Natural iron fertilisation from Southern Ocean islands results in high primary production and phytoplankton biomass accumulations readily visible in satellite ocean colour observations. These images reveal great spatial complexity with highly varying concentrations of chlorophyll, presumably reflecting both variations in iron supply and conditions favouring phytoplankton accumulation. To examine the second aspect, in particular the influences of variations in temperature and mixed layer depth, we deployed four autonomous profiling floats in the Antarctic Circumpolar Current near the Kerguelen Plateau in the Indian sector of the Southern Ocean. Each "bio-profiler" measured more than 250 profiles of temperature (T), salinity (S), dissolved oxygen, chlorophyll a (Chl a) fluorescence, and particulate backscattering (b bp ) in the top 300 m of the water column, sampling up to 5 profiles per day along meandering trajectories extending up to 1000 km. Comparison of surface Chl a estimates (analogous to values from satellite images) with total water column inventories revealed largely linear relationships, suggesting that these images provide credible information on total and not just surface biomass spatial distributions. However, they also showed that physical mixed layer depths are often not a reliable guide to biomass distributions. Regions of very high Chl a accumulation (1.5-10 μg L -1 ) were associated predominantly with a narrow T-S class of surface waters. In contrast, waters with only moderate Chl a enrichments (0.5-1.5 μg L -1 ) displayed no clear correlation with specific water properties, including no dependence on mixed layer depth or the intensity of stratification. Geostrophic trajectory analysis suggests that both these observations can be explained if the main determinant of biomass in a given water parcel is the time since leaving the Kerguelen Plateau. One float became trapped in a cyclonic eddy, allowing temporal evaluation of the water column in early autumn. During this ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Antarctic Southern Ocean The Antarctic Kerguelen Indian |