The structure of diatom communities constrains biogeochemical properties in surface waters of the Southern Ocean (Kerguelen Plateau)
International audience In the context of climate change, understanding the ecological processes controlling the functioning and the efficiency of the biological pump is of primary importance. Plankton community structure and species-specific properties are often invoked as likely to affect biogeoche...
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ftinsu:oai:HAL:hal-03035828v1 2023-05-15T17:02:09+02:00 The structure of diatom communities constrains biogeochemical properties in surface waters of the Southern Ocean (Kerguelen Plateau) Lafond, Augustin Leblanc, Karine Legras, Justine Cornet, Veronique Queguiner, Bernard Institut méditerranéen d'océanologie (MIO) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS) 2020 https://hal.science/hal-03035828 https://hal.science/hal-03035828/document https://hal.science/hal-03035828/file/Lafond,2020-subm.pdf en eng HAL CCSD Elsevier hal-03035828 https://hal.science/hal-03035828 https://hal.science/hal-03035828/document https://hal.science/hal-03035828/file/Lafond,2020-subm.pdf info:eu-repo/semantics/OpenAccess ISSN: 0924-7963 Journal of Marine Systems https://hal.science/hal-03035828 Journal of Marine Systems, 2020, 212, pp.103458 Southern Ocean Kerguelen Plateau Diatoms Community structure Biological pump Biological carbon pump mortality modes diversity deep particle stocks [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDE.BE]Environmental Sciences/Biodiversity and Ecology info:eu-repo/semantics/article Journal articles 2020 ftinsu 2023-03-15T19:15:01Z International audience In the context of climate change, understanding the ecological processes controlling the functioning and the efficiency of the biological pump is of primary importance. Plankton community structure and species-specific properties are often invoked as likely to affect biogeochemistry and the export of organic and biogenic material to the ocean interior. Although a major player in this respect, diatoms are still viewed as a single functional type whose diversity is generally overlooked. Here we examine that question, building on the results achieved during the MOBYDICK expedition, which occurred in the vicinity of the Kerguelen Islands (Southern Ocean) in late summer, a time window corresponding to the demise of the annually recurrent phytoplankton blooms already known to be controlled by iron availability. The Si/C/N stoichiometry of the particulate matter was studied in conjunction with the different diatom community structures, their physiological states, as well as their species-specific carbon contents and silicification degrees. Our results show that diatoms outside the ironfertilized plateau were more heavily silicified, due to the combined effects of both taxonomic composition of the resident community and a direct physiological response to iron stress, resulting in higher Si:C elemental ratios in diatoms as well as in the bulk particulate matter. Despite low silicic acid concentrations, large chains of weakly silicified Corethron inerme were able to grow in the upper mixed layer above the plateau, while in adjacent high nutrient low chlorophyll (HNLC) waters, communities were dominated by Fragilariopsis spp., Cylindrotheca closterium and the centric genera Actinocyclus/Thalassiosira spp. Depth was also an important factor shaping diatom communities, with the presence of a deep and inactive assemblage located within the pycnocline gradient, both on-and off-plateau, which likely resulted from the differential sinking and accumulation of species previously grown at the surface. In ... Article in Journal/Newspaper Kerguelen Islands Southern Ocean Institut national des sciences de l'Univers: HAL-INSU Kerguelen Kerguelen Islands Southern Ocean |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
Southern Ocean Kerguelen Plateau Diatoms Community structure Biological pump Biological carbon pump mortality modes diversity deep particle stocks [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDE.BE]Environmental Sciences/Biodiversity and Ecology |
spellingShingle |
Southern Ocean Kerguelen Plateau Diatoms Community structure Biological pump Biological carbon pump mortality modes diversity deep particle stocks [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDE.BE]Environmental Sciences/Biodiversity and Ecology Lafond, Augustin Leblanc, Karine Legras, Justine Cornet, Veronique Queguiner, Bernard The structure of diatom communities constrains biogeochemical properties in surface waters of the Southern Ocean (Kerguelen Plateau) |
topic_facet |
Southern Ocean Kerguelen Plateau Diatoms Community structure Biological pump Biological carbon pump mortality modes diversity deep particle stocks [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDE.BE]Environmental Sciences/Biodiversity and Ecology |
description |
International audience In the context of climate change, understanding the ecological processes controlling the functioning and the efficiency of the biological pump is of primary importance. Plankton community structure and species-specific properties are often invoked as likely to affect biogeochemistry and the export of organic and biogenic material to the ocean interior. Although a major player in this respect, diatoms are still viewed as a single functional type whose diversity is generally overlooked. Here we examine that question, building on the results achieved during the MOBYDICK expedition, which occurred in the vicinity of the Kerguelen Islands (Southern Ocean) in late summer, a time window corresponding to the demise of the annually recurrent phytoplankton blooms already known to be controlled by iron availability. The Si/C/N stoichiometry of the particulate matter was studied in conjunction with the different diatom community structures, their physiological states, as well as their species-specific carbon contents and silicification degrees. Our results show that diatoms outside the ironfertilized plateau were more heavily silicified, due to the combined effects of both taxonomic composition of the resident community and a direct physiological response to iron stress, resulting in higher Si:C elemental ratios in diatoms as well as in the bulk particulate matter. Despite low silicic acid concentrations, large chains of weakly silicified Corethron inerme were able to grow in the upper mixed layer above the plateau, while in adjacent high nutrient low chlorophyll (HNLC) waters, communities were dominated by Fragilariopsis spp., Cylindrotheca closterium and the centric genera Actinocyclus/Thalassiosira spp. Depth was also an important factor shaping diatom communities, with the presence of a deep and inactive assemblage located within the pycnocline gradient, both on-and off-plateau, which likely resulted from the differential sinking and accumulation of species previously grown at the surface. In ... |
author2 |
Institut méditerranéen d'océanologie (MIO) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Lafond, Augustin Leblanc, Karine Legras, Justine Cornet, Veronique Queguiner, Bernard |
author_facet |
Lafond, Augustin Leblanc, Karine Legras, Justine Cornet, Veronique Queguiner, Bernard |
author_sort |
Lafond, Augustin |
title |
The structure of diatom communities constrains biogeochemical properties in surface waters of the Southern Ocean (Kerguelen Plateau) |
title_short |
The structure of diatom communities constrains biogeochemical properties in surface waters of the Southern Ocean (Kerguelen Plateau) |
title_full |
The structure of diatom communities constrains biogeochemical properties in surface waters of the Southern Ocean (Kerguelen Plateau) |
title_fullStr |
The structure of diatom communities constrains biogeochemical properties in surface waters of the Southern Ocean (Kerguelen Plateau) |
title_full_unstemmed |
The structure of diatom communities constrains biogeochemical properties in surface waters of the Southern Ocean (Kerguelen Plateau) |
title_sort |
structure of diatom communities constrains biogeochemical properties in surface waters of the southern ocean (kerguelen plateau) |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://hal.science/hal-03035828 https://hal.science/hal-03035828/document https://hal.science/hal-03035828/file/Lafond,2020-subm.pdf |
geographic |
Kerguelen Kerguelen Islands Southern Ocean |
geographic_facet |
Kerguelen Kerguelen Islands Southern Ocean |
genre |
Kerguelen Islands Southern Ocean |
genre_facet |
Kerguelen Islands Southern Ocean |
op_source |
ISSN: 0924-7963 Journal of Marine Systems https://hal.science/hal-03035828 Journal of Marine Systems, 2020, 212, pp.103458 |
op_relation |
hal-03035828 https://hal.science/hal-03035828 https://hal.science/hal-03035828/document https://hal.science/hal-03035828/file/Lafond,2020-subm.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766055400022474752 |