Biogeochemical study of coccolithophorid blooms in the context of climate change
Coccolithophores are unicellular microscopic algae (Haptophyta) surrounded by calcium carbonate plates that are produced during their life cycle. These species, whose contemporary contributor is Emiliania huxleyi, are mainly found in the sub-polar and temperate oceans, where they produce huge blooms...
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ULB - Université Libre de Bruxelles
2009
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ftorbi:oai:orbi.ulg.ac.be:2268/80864 2024-04-21T08:09:47+00:00 Biogeochemical study of coccolithophorid blooms in the context of climate change Harlay, Jérôme Chou, Lei 2009-03-20 503 https://orbi.uliege.be/handle/2268/80864 en eng ULB - Université Libre de Bruxelles https://orbi.uliege.be/handle/2268/80864 info:hdl:2268/80864 restricted access http://purl.org/coar/access_right/c_16ec info:eu-repo/semantics/restrictedAccess coccolithophore calcification primary production Emiliania huxleyi Atlantic bloom calcium carbonate Life sciences Aquatic sciences & oceanology Environmental sciences & ecology Sciences du vivant Sciences aquatiques & océanologie Sciences de l’environnement & écologie doctoral thesis http://purl.org/coar/resource_type/c_db06 info:eu-repo/semantics/doctoralThesis 2009 ftorbi 2024-03-27T14:43:31Z Coccolithophores are unicellular microscopic algae (Haptophyta) surrounded by calcium carbonate plates that are produced during their life cycle. These species, whose contemporary contributor is Emiliania huxleyi, are mainly found in the sub-polar and temperate oceans, where they produce huge blooms visible from space. Coccolithophores are sensitive to ocean acidification that results from the ongoing accumulation of anthropogenic carbon dioxide (CO2) in the atmosphere. The response of these organisms to global change appears to be related to the reduction of their ability to produce calcium carbonate at the cellular level. At the community levels, one anticipates changes in the carbon fluxes associated to their blooms as calcification is reduced. However, the consequences of such environmental changes on this species are speculative and require improvements in the description of the mechanisms controlling the organic and inorganic carbon production and export. The first aspect of this work was to study the response of these organisms to artificially modified CO2 concentrations representative of the conditions occurring in the past (glacial) and those expected by the end of the century (2100). Two different levels were examined: the continuous monospecific cultures (chemostats) allowed us to work at the cellular level while the mesocosms gave light to the mechanisms taking place in an isolated fraction of the natural community. The second aspect of this work consisted of field studies carried out during four cruises (2002, 2003, 2004 and 2006) in the northern Bay of Biscay, where the occurrence of E. huxleyi blooms were observed in late spring. I describe the vertical profiles of biogeochemical variables (nutrients, chlorophyll-a, dissolved inorganic carbon chemistry, particulate carbon, transparent exopolymer particles (TEP)) and study processes such as primary production, calcification and bacterial production. The properties of these blooms are compared with those reported in the literature and enriched with ... Doctoral or Postdoctoral Thesis Ocean acidification University of Liège: ORBi (Open Repository and Bibliography) |
institution |
Open Polar |
collection |
University of Liège: ORBi (Open Repository and Bibliography) |
op_collection_id |
ftorbi |
language |
English |
topic |
coccolithophore calcification primary production Emiliania huxleyi Atlantic bloom calcium carbonate Life sciences Aquatic sciences & oceanology Environmental sciences & ecology Sciences du vivant Sciences aquatiques & océanologie Sciences de l’environnement & écologie |
spellingShingle |
coccolithophore calcification primary production Emiliania huxleyi Atlantic bloom calcium carbonate Life sciences Aquatic sciences & oceanology Environmental sciences & ecology Sciences du vivant Sciences aquatiques & océanologie Sciences de l’environnement & écologie Harlay, Jérôme Biogeochemical study of coccolithophorid blooms in the context of climate change |
topic_facet |
coccolithophore calcification primary production Emiliania huxleyi Atlantic bloom calcium carbonate Life sciences Aquatic sciences & oceanology Environmental sciences & ecology Sciences du vivant Sciences aquatiques & océanologie Sciences de l’environnement & écologie |
description |
Coccolithophores are unicellular microscopic algae (Haptophyta) surrounded by calcium carbonate plates that are produced during their life cycle. These species, whose contemporary contributor is Emiliania huxleyi, are mainly found in the sub-polar and temperate oceans, where they produce huge blooms visible from space. Coccolithophores are sensitive to ocean acidification that results from the ongoing accumulation of anthropogenic carbon dioxide (CO2) in the atmosphere. The response of these organisms to global change appears to be related to the reduction of their ability to produce calcium carbonate at the cellular level. At the community levels, one anticipates changes in the carbon fluxes associated to their blooms as calcification is reduced. However, the consequences of such environmental changes on this species are speculative and require improvements in the description of the mechanisms controlling the organic and inorganic carbon production and export. The first aspect of this work was to study the response of these organisms to artificially modified CO2 concentrations representative of the conditions occurring in the past (glacial) and those expected by the end of the century (2100). Two different levels were examined: the continuous monospecific cultures (chemostats) allowed us to work at the cellular level while the mesocosms gave light to the mechanisms taking place in an isolated fraction of the natural community. The second aspect of this work consisted of field studies carried out during four cruises (2002, 2003, 2004 and 2006) in the northern Bay of Biscay, where the occurrence of E. huxleyi blooms were observed in late spring. I describe the vertical profiles of biogeochemical variables (nutrients, chlorophyll-a, dissolved inorganic carbon chemistry, particulate carbon, transparent exopolymer particles (TEP)) and study processes such as primary production, calcification and bacterial production. The properties of these blooms are compared with those reported in the literature and enriched with ... |
author2 |
Chou, Lei |
format |
Doctoral or Postdoctoral Thesis |
author |
Harlay, Jérôme |
author_facet |
Harlay, Jérôme |
author_sort |
Harlay, Jérôme |
title |
Biogeochemical study of coccolithophorid blooms in the context of climate change |
title_short |
Biogeochemical study of coccolithophorid blooms in the context of climate change |
title_full |
Biogeochemical study of coccolithophorid blooms in the context of climate change |
title_fullStr |
Biogeochemical study of coccolithophorid blooms in the context of climate change |
title_full_unstemmed |
Biogeochemical study of coccolithophorid blooms in the context of climate change |
title_sort |
biogeochemical study of coccolithophorid blooms in the context of climate change |
publisher |
ULB - Université Libre de Bruxelles |
publishDate |
2009 |
url |
https://orbi.uliege.be/handle/2268/80864 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_relation |
https://orbi.uliege.be/handle/2268/80864 info:hdl:2268/80864 |
op_rights |
restricted access http://purl.org/coar/access_right/c_16ec info:eu-repo/semantics/restrictedAccess |
_version_ |
1796951006368497664 |