Export fluxes in a naturally iron-fertilized area of the Southern Ocean - Part 2: Importance of diatom resting spores and faecal pellets for export
International audience The biological composition of the material exported to a moored sediment trap located under the winter mixed layer of the naturally fertilized Kerguelen Plateau in the Southern Ocean was studied over an annual cycle. Despite iron availability in spring, the annual particulate...
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ftccsdartic:oai:HAL:hal-04109909v1 2023-06-18T03:36:55+02:00 Export fluxes in a naturally iron-fertilized area of the Southern Ocean - Part 2: Importance of diatom resting spores and faecal pellets for export Rembauville, M. Blain, S. Armand, L. Quéguiner, B. Salter, I. Aix Marseille Université (AMU) 2015 https://hal.science/hal-04109909 https://doi.org/10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014 en eng HAL CCSD info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014 hal-04109909 https://hal.science/hal-04109909 BIBCODE: 2015BGeo.12.3171R doi:10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014 Biogeosciences https://hal.science/hal-04109909 Biogeosciences, 2015, 12, pp.3171-3195. ⟨10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014⟩ Earth Science [SDU]Sciences of the Universe [physics] info:eu-repo/semantics/article Journal articles 2015 ftccsdartic https://doi.org/10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014 2023-06-03T23:53:56Z International audience The biological composition of the material exported to a moored sediment trap located under the winter mixed layer of the naturally fertilized Kerguelen Plateau in the Southern Ocean was studied over an annual cycle. Despite iron availability in spring, the annual particulate organic carbon (POC) export (98.2 mmol m -2 ) at 289 m was low, but annual biogenic silica export was significant (114 mmol m -2 ). This feature was related to the abundance of empty diatom cells and the ratio of full to empty cells exerted a first-order control in BSi : POC export stoichiometry of the biological pump. Chaetoceros Hyalochaete spp. and Thalassiosira antarctica resting spores were responsible for more than 60% of the annual POC flux that occurred during two very short export events of < 14 days in spring-summer. Relatively low diatom fluxes were observed over the remainder of the year. Faecal pellet contribution to annual carbon flux was lower (34%) and reached its seasonal maximum in autumn and winter (> 80%). The seasonal progression of faecal pellet types revealed a clear transition from small spherical shapes (small copepods) in spring, to larger cylindrical and ellipsoid shapes in summer (euphausiids and large copepods) and finally to large tabular shapes (salps) in autumn and winter. We propose in this high-biomass, low-export (HBLE) environment that small but highly silicified and fast-sinking resting spores are able to bypass the intense grazing pressure and efficient carbon transfer to higher trophic levels that are responsible for the low fluxes observed the during the remainder of the year. More generally our study also provides a statistical framework linking the ecological succession of diatom and zooplankton communities to the seasonality of carbon and silicon export within an iron-fertilized bloom region in the Southern Ocean. Article in Journal/Newspaper Antarc* Antarctica Southern Ocean Copepods Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Southern Ocean Kerguelen |
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 |
Earth Science [SDU]Sciences of the Universe [physics] |
spellingShingle |
Earth Science [SDU]Sciences of the Universe [physics] Rembauville, M. Blain, S. Armand, L. Quéguiner, B. Salter, I. Export fluxes in a naturally iron-fertilized area of the Southern Ocean - Part 2: Importance of diatom resting spores and faecal pellets for export |
topic_facet |
Earth Science [SDU]Sciences of the Universe [physics] |
description |
International audience The biological composition of the material exported to a moored sediment trap located under the winter mixed layer of the naturally fertilized Kerguelen Plateau in the Southern Ocean was studied over an annual cycle. Despite iron availability in spring, the annual particulate organic carbon (POC) export (98.2 mmol m -2 ) at 289 m was low, but annual biogenic silica export was significant (114 mmol m -2 ). This feature was related to the abundance of empty diatom cells and the ratio of full to empty cells exerted a first-order control in BSi : POC export stoichiometry of the biological pump. Chaetoceros Hyalochaete spp. and Thalassiosira antarctica resting spores were responsible for more than 60% of the annual POC flux that occurred during two very short export events of < 14 days in spring-summer. Relatively low diatom fluxes were observed over the remainder of the year. Faecal pellet contribution to annual carbon flux was lower (34%) and reached its seasonal maximum in autumn and winter (> 80%). The seasonal progression of faecal pellet types revealed a clear transition from small spherical shapes (small copepods) in spring, to larger cylindrical and ellipsoid shapes in summer (euphausiids and large copepods) and finally to large tabular shapes (salps) in autumn and winter. We propose in this high-biomass, low-export (HBLE) environment that small but highly silicified and fast-sinking resting spores are able to bypass the intense grazing pressure and efficient carbon transfer to higher trophic levels that are responsible for the low fluxes observed the during the remainder of the year. More generally our study also provides a statistical framework linking the ecological succession of diatom and zooplankton communities to the seasonality of carbon and silicon export within an iron-fertilized bloom region in the Southern Ocean. |
author2 |
Aix Marseille Université (AMU) |
format |
Article in Journal/Newspaper |
author |
Rembauville, M. Blain, S. Armand, L. Quéguiner, B. Salter, I. |
author_facet |
Rembauville, M. Blain, S. Armand, L. Quéguiner, B. Salter, I. |
author_sort |
Rembauville, M. |
title |
Export fluxes in a naturally iron-fertilized area of the Southern Ocean - Part 2: Importance of diatom resting spores and faecal pellets for export |
title_short |
Export fluxes in a naturally iron-fertilized area of the Southern Ocean - Part 2: Importance of diatom resting spores and faecal pellets for export |
title_full |
Export fluxes in a naturally iron-fertilized area of the Southern Ocean - Part 2: Importance of diatom resting spores and faecal pellets for export |
title_fullStr |
Export fluxes in a naturally iron-fertilized area of the Southern Ocean - Part 2: Importance of diatom resting spores and faecal pellets for export |
title_full_unstemmed |
Export fluxes in a naturally iron-fertilized area of the Southern Ocean - Part 2: Importance of diatom resting spores and faecal pellets for export |
title_sort |
export fluxes in a naturally iron-fertilized area of the southern ocean - part 2: importance of diatom resting spores and faecal pellets for export |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://hal.science/hal-04109909 https://doi.org/10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014 |
geographic |
Southern Ocean Kerguelen |
geographic_facet |
Southern Ocean Kerguelen |
genre |
Antarc* Antarctica Southern Ocean Copepods |
genre_facet |
Antarc* Antarctica Southern Ocean Copepods |
op_source |
Biogeosciences https://hal.science/hal-04109909 Biogeosciences, 2015, 12, pp.3171-3195. ⟨10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014 hal-04109909 https://hal.science/hal-04109909 BIBCODE: 2015BGeo.12.3171R doi:10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014 |
op_doi |
https://doi.org/10.5194/bg-12-3171-201510.5194/bgd-11-17089-2014 |
_version_ |
1769009043668467712 |