Migration verticale du zooplancton et flux respiratoire de carbone en mer de Beaufort (Arctique canadien)
Zooplankton play a pivotal role in the energy transfer through the oceanic food webs and in the biogeochemical carbon cycle within marine ecosystems. The entire community recycles CO2 by consuming photosynthetically fixed carbon and respiring it thereafter. Vertical migrants transport stored carbon...
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fttriple:oai:gotriple.eu:http://hdl.handle.net/20.500.11794/24282 2023-05-15T14:52:57+02:00 Migration verticale du zooplancton et flux respiratoire de carbone en mer de Beaufort (Arctique canadien) Vertical migration of zooplankton and respiratory carbon flow in the Beaufort Sea (Canadian Arctic) Darnis, Gérald Fortier, Louis Beaufort, Mer de 2013-01-01 https://hdl.handle.net/20.500.11794/24282 fr fre Université Laval http://hdl.handle.net/20.500.11794/24282 other CorpusUL envir geo Thesis https://vocabularies.coar-repositories.org/resource_types/c_46ec/ 2013 fttriple https://doi.org/20.500.11794/24282 2023-01-22T17:43:08Z Zooplankton play a pivotal role in the energy transfer through the oceanic food webs and in the biogeochemical carbon cycle within marine ecosystems. The entire community recycles CO2 by consuming photosynthetically fixed carbon and respiring it thereafter. Vertical migrants transport stored carbon and respire it at depth, thus, contributing to its export from the epipelagic zone. Active respiratory flux has not been measured in the Arctic despite the high potential for transport due to the strong contribution of the seasonal migrant Calanus hyperboreus to zooplankton biomass. This thesis exploits a quasi-annual time series of zooplankton biomass and respiration profiles to: (1) quantify this process in the Beaufort Sea; (2) improve our knowledge on the seasonal fluctuations of the vertical distribution of seven key arctic copepods; and (3) track the life cycle of Calanus hyperboreus. This large herbivore contributed 45% to the zooplankton biomass and performed the most extensive vertical migration. Its seasonal ascent, ranging about 200 m, and those of lesser magnitude of C. glacialis and the small omnivore Oithona similis, coincided with the ice algae and phytoplankton blooms. Despite vigorous winter reproduction at depth, a precocious ice break-up, and high spring-summer primary production, weak recruitment to copepodite stage caused C. hyperboreus population growth to stagnate. In their mesopelagic habitat, the highly abundant omnivore Metridia longa, and Microcalanus pygmaeus, could have exerted a control on this population by intercepting C. hyperboreus eggs floating toward the surface. The cryophilic Pseudocalanus spp. remained year-round in the cold epipelagic zone while the mesopelagic Triconia borealis, likely a semi-parasite of C. hyperboreus, was associated with it in the warmer Atlantic layer. Temperature had little effect on the vertical displacements of arctic copepods. The Calanus-dominated large zooplankton was responsible for 89% of zooplankton grazing on the April-July gross primary ... Thesis Arctic Arctique* Beaufort Sea Calanus hyperboreus ice algae Mer de Beaufort Phytoplankton Zooplankton Copepods Unknown Arctic Mer de Beaufort ENVELOPE(-138.005,-138.005,69.500,69.500) |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
fttriple |
language |
French |
topic |
envir geo |
spellingShingle |
envir geo Darnis, Gérald Migration verticale du zooplancton et flux respiratoire de carbone en mer de Beaufort (Arctique canadien) |
topic_facet |
envir geo |
description |
Zooplankton play a pivotal role in the energy transfer through the oceanic food webs and in the biogeochemical carbon cycle within marine ecosystems. The entire community recycles CO2 by consuming photosynthetically fixed carbon and respiring it thereafter. Vertical migrants transport stored carbon and respire it at depth, thus, contributing to its export from the epipelagic zone. Active respiratory flux has not been measured in the Arctic despite the high potential for transport due to the strong contribution of the seasonal migrant Calanus hyperboreus to zooplankton biomass. This thesis exploits a quasi-annual time series of zooplankton biomass and respiration profiles to: (1) quantify this process in the Beaufort Sea; (2) improve our knowledge on the seasonal fluctuations of the vertical distribution of seven key arctic copepods; and (3) track the life cycle of Calanus hyperboreus. This large herbivore contributed 45% to the zooplankton biomass and performed the most extensive vertical migration. Its seasonal ascent, ranging about 200 m, and those of lesser magnitude of C. glacialis and the small omnivore Oithona similis, coincided with the ice algae and phytoplankton blooms. Despite vigorous winter reproduction at depth, a precocious ice break-up, and high spring-summer primary production, weak recruitment to copepodite stage caused C. hyperboreus population growth to stagnate. In their mesopelagic habitat, the highly abundant omnivore Metridia longa, and Microcalanus pygmaeus, could have exerted a control on this population by intercepting C. hyperboreus eggs floating toward the surface. The cryophilic Pseudocalanus spp. remained year-round in the cold epipelagic zone while the mesopelagic Triconia borealis, likely a semi-parasite of C. hyperboreus, was associated with it in the warmer Atlantic layer. Temperature had little effect on the vertical displacements of arctic copepods. The Calanus-dominated large zooplankton was responsible for 89% of zooplankton grazing on the April-July gross primary ... |
author2 |
Fortier, Louis |
format |
Thesis |
author |
Darnis, Gérald |
author_facet |
Darnis, Gérald |
author_sort |
Darnis, Gérald |
title |
Migration verticale du zooplancton et flux respiratoire de carbone en mer de Beaufort (Arctique canadien) |
title_short |
Migration verticale du zooplancton et flux respiratoire de carbone en mer de Beaufort (Arctique canadien) |
title_full |
Migration verticale du zooplancton et flux respiratoire de carbone en mer de Beaufort (Arctique canadien) |
title_fullStr |
Migration verticale du zooplancton et flux respiratoire de carbone en mer de Beaufort (Arctique canadien) |
title_full_unstemmed |
Migration verticale du zooplancton et flux respiratoire de carbone en mer de Beaufort (Arctique canadien) |
title_sort |
migration verticale du zooplancton et flux respiratoire de carbone en mer de beaufort (arctique canadien) |
publisher |
Université Laval |
publishDate |
2013 |
url |
https://hdl.handle.net/20.500.11794/24282 |
op_coverage |
Beaufort, Mer de |
long_lat |
ENVELOPE(-138.005,-138.005,69.500,69.500) |
geographic |
Arctic Mer de Beaufort |
geographic_facet |
Arctic Mer de Beaufort |
genre |
Arctic Arctique* Beaufort Sea Calanus hyperboreus ice algae Mer de Beaufort Phytoplankton Zooplankton Copepods |
genre_facet |
Arctic Arctique* Beaufort Sea Calanus hyperboreus ice algae Mer de Beaufort Phytoplankton Zooplankton Copepods |
op_source |
CorpusUL |
op_relation |
http://hdl.handle.net/20.500.11794/24282 |
op_rights |
other |
op_doi |
https://doi.org/20.500.11794/24282 |
_version_ |
1766324357885329408 |