Characterization of Bio‐Optical Anomalies in the Kerguelen Region, Southern Indian Ocean: A Study Based on Shipborne Sampling and BioGeoChemical‐Argo Profiling Floats
International audience Abstract The Southern Ocean (SO) is known for its atypical bio‐optical regime. This complicates the interpretation of proxies measured from satellite and in situ platforms equipped with optical sensors, which occupy an important niche for monitoring the vast and remote SO. A s...
Published in: | Journal of Geophysical Research: Oceans |
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Main Authors: | , , , , , , , , , , , , |
Other Authors: | , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2023
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Subjects: | |
Online Access: | https://hal.science/hal-04362574 https://hal.science/hal-04362574/document https://hal.science/hal-04362574/file/JGR%20Oceans%20-%202023%20-%20Uitz%20-%20Characterization%20of%20Bio%E2%80%90Optical%20Anomalies%20in%20the%20Kerguelen%20Region%20Southern%20Indian%20Ocean%20A.pdf https://doi.org/10.1029/2023JC019671 |
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openpolar |
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Open Polar |
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Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SDE]Environmental Sciences |
spellingShingle |
[SDE]Environmental Sciences Uitz, J. Roesler, C. Organelli, E. Claustre, H. Penkerc'H, C. Drapeau, S. Leymarie, E. Poteau, A. Schmechtig, C. Dimier, C. Ras, J. Xing, X. Blain, S. Characterization of Bio‐Optical Anomalies in the Kerguelen Region, Southern Indian Ocean: A Study Based on Shipborne Sampling and BioGeoChemical‐Argo Profiling Floats |
topic_facet |
[SDE]Environmental Sciences |
description |
International audience Abstract The Southern Ocean (SO) is known for its atypical bio‐optical regime. This complicates the interpretation of proxies measured from satellite and in situ platforms equipped with optical sensors, which occupy an important niche for monitoring the vast and remote SO. A ship‐based field study in concert with time series observations from BioGeoChemical‐Argo (BGC‐Argo) profiling floats were used to investigate spatial and temporal variations in bio‐optical relationships in the open ocean waters surrounding the Kerguelen Plateau in the Indian sector of the SO. Compared to other regions with similar chlorophyll concentrations, chlorophyll‐specific phytoplankton absorption in the blue waveband presented a consistent negative anomaly. The anomaly was uniform over deep mixed layers and correlated with phytoplankton size, photoacclimation and atypically high concentrations of fucoxanthin. The BGC‐Argo observation‐based proxies revealed that the blue absorption anomaly increased with chlorophyll concentration both spatially and temporally and, while particularly pronounced in the naturally iron‐fertilized waters, was also found in the High Nutrient Low Chlorophyll region. While phytoplankton size was an important driver of the anomaly, photoacclimation associated with self‐shading of phytoplankton cells was also involved during intense booms. The backscattering coefficient exhibited negative and positive anomalies in the low and high biomass regimes, respectively. The large positive anomaly in high biomass regimes was attributed to the variable non‐algal particles characteristics associated with a relatively high production of bloom by‐products. With clear understanding of the bio‐optical anomalies, BGC‐Argo floats stand as unique tools for monitoring the bio‐optical spatio‐temporal complexity of the SO. |
author2 |
Laboratoire d'océanographie de Villefranche (LOV) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Observatoire des sciences de l'univers Ecce Terra Paris (OSU ECCE TERRA) École normale supérieure - Paris (ENS-PSL) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Laboratoire d'Océanographie Microbienne (LOMIC) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Uitz, J. Roesler, C. Organelli, E. Claustre, H. Penkerc'H, C. Drapeau, S. Leymarie, E. Poteau, A. Schmechtig, C. Dimier, C. Ras, J. Xing, X. Blain, S. |
author_facet |
Uitz, J. Roesler, C. Organelli, E. Claustre, H. Penkerc'H, C. Drapeau, S. Leymarie, E. Poteau, A. Schmechtig, C. Dimier, C. Ras, J. Xing, X. Blain, S. |
author_sort |
Uitz, J. |
title |
Characterization of Bio‐Optical Anomalies in the Kerguelen Region, Southern Indian Ocean: A Study Based on Shipborne Sampling and BioGeoChemical‐Argo Profiling Floats |
title_short |
Characterization of Bio‐Optical Anomalies in the Kerguelen Region, Southern Indian Ocean: A Study Based on Shipborne Sampling and BioGeoChemical‐Argo Profiling Floats |
title_full |
Characterization of Bio‐Optical Anomalies in the Kerguelen Region, Southern Indian Ocean: A Study Based on Shipborne Sampling and BioGeoChemical‐Argo Profiling Floats |
title_fullStr |
Characterization of Bio‐Optical Anomalies in the Kerguelen Region, Southern Indian Ocean: A Study Based on Shipborne Sampling and BioGeoChemical‐Argo Profiling Floats |
title_full_unstemmed |
Characterization of Bio‐Optical Anomalies in the Kerguelen Region, Southern Indian Ocean: A Study Based on Shipborne Sampling and BioGeoChemical‐Argo Profiling Floats |
title_sort |
characterization of bio‐optical anomalies in the kerguelen region, southern indian ocean: a study based on shipborne sampling and biogeochemical‐argo profiling floats |
publisher |
HAL CCSD |
publishDate |
2023 |
url |
https://hal.science/hal-04362574 https://hal.science/hal-04362574/document https://hal.science/hal-04362574/file/JGR%20Oceans%20-%202023%20-%20Uitz%20-%20Characterization%20of%20Bio%E2%80%90Optical%20Anomalies%20in%20the%20Kerguelen%20Region%20Southern%20Indian%20Ocean%20A.pdf https://doi.org/10.1029/2023JC019671 |
geographic |
Indian Kerguelen Southern Ocean |
geographic_facet |
Indian Kerguelen Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://hal.science/hal-04362574 Journal of Geophysical Research. Oceans, 2023, 128 (12), ⟨10.1029/2023JC019671⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2023JC019671 hal-04362574 https://hal.science/hal-04362574 https://hal.science/hal-04362574/document https://hal.science/hal-04362574/file/JGR%20Oceans%20-%202023%20-%20Uitz%20-%20Characterization%20of%20Bio%E2%80%90Optical%20Anomalies%20in%20the%20Kerguelen%20Region%20Southern%20Indian%20Ocean%20A.pdf doi:10.1029/2023JC019671 |
op_rights |
http://creativecommons.org/licenses/by-nc-nd/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/2023JC019671 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
128 |
container_issue |
12 |
_version_ |
1789339206290505728 |
spelling |
ftinsu:oai:HAL:hal-04362574v1 2024-01-28T10:09:22+01:00 Characterization of Bio‐Optical Anomalies in the Kerguelen Region, Southern Indian Ocean: A Study Based on Shipborne Sampling and BioGeoChemical‐Argo Profiling Floats Uitz, J. Roesler, C. Organelli, E. Claustre, H. Penkerc'H, C. Drapeau, S. Leymarie, E. Poteau, A. Schmechtig, C. Dimier, C. Ras, J. Xing, X. Blain, S. Laboratoire d'océanographie de Villefranche (LOV) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Observatoire des sciences de l'univers Ecce Terra Paris (OSU ECCE TERRA) École normale supérieure - Paris (ENS-PSL) Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Laboratoire d'Océanographie Microbienne (LOMIC) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) 2023-12-13 https://hal.science/hal-04362574 https://hal.science/hal-04362574/document https://hal.science/hal-04362574/file/JGR%20Oceans%20-%202023%20-%20Uitz%20-%20Characterization%20of%20Bio%E2%80%90Optical%20Anomalies%20in%20the%20Kerguelen%20Region%20Southern%20Indian%20Ocean%20A.pdf https://doi.org/10.1029/2023JC019671 en eng HAL CCSD Wiley-Blackwell info:eu-repo/semantics/altIdentifier/doi/10.1029/2023JC019671 hal-04362574 https://hal.science/hal-04362574 https://hal.science/hal-04362574/document https://hal.science/hal-04362574/file/JGR%20Oceans%20-%202023%20-%20Uitz%20-%20Characterization%20of%20Bio%E2%80%90Optical%20Anomalies%20in%20the%20Kerguelen%20Region%20Southern%20Indian%20Ocean%20A.pdf doi:10.1029/2023JC019671 http://creativecommons.org/licenses/by-nc-nd/ info:eu-repo/semantics/OpenAccess ISSN: 2169-9275 EISSN: 2169-9291 Journal of Geophysical Research. Oceans https://hal.science/hal-04362574 Journal of Geophysical Research. Oceans, 2023, 128 (12), ⟨10.1029/2023JC019671⟩ [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2023 ftinsu https://doi.org/10.1029/2023JC019671 2024-01-03T17:22:31Z International audience Abstract The Southern Ocean (SO) is known for its atypical bio‐optical regime. This complicates the interpretation of proxies measured from satellite and in situ platforms equipped with optical sensors, which occupy an important niche for monitoring the vast and remote SO. A ship‐based field study in concert with time series observations from BioGeoChemical‐Argo (BGC‐Argo) profiling floats were used to investigate spatial and temporal variations in bio‐optical relationships in the open ocean waters surrounding the Kerguelen Plateau in the Indian sector of the SO. Compared to other regions with similar chlorophyll concentrations, chlorophyll‐specific phytoplankton absorption in the blue waveband presented a consistent negative anomaly. The anomaly was uniform over deep mixed layers and correlated with phytoplankton size, photoacclimation and atypically high concentrations of fucoxanthin. The BGC‐Argo observation‐based proxies revealed that the blue absorption anomaly increased with chlorophyll concentration both spatially and temporally and, while particularly pronounced in the naturally iron‐fertilized waters, was also found in the High Nutrient Low Chlorophyll region. While phytoplankton size was an important driver of the anomaly, photoacclimation associated with self‐shading of phytoplankton cells was also involved during intense booms. The backscattering coefficient exhibited negative and positive anomalies in the low and high biomass regimes, respectively. The large positive anomaly in high biomass regimes was attributed to the variable non‐algal particles characteristics associated with a relatively high production of bloom by‐products. With clear understanding of the bio‐optical anomalies, BGC‐Argo floats stand as unique tools for monitoring the bio‐optical spatio‐temporal complexity of the SO. Article in Journal/Newspaper Southern Ocean Institut national des sciences de l'Univers: HAL-INSU Indian Kerguelen Southern Ocean Journal of Geophysical Research: Oceans 128 12 |