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1. Phytoplankton diversity and community composition along the estuarine gradient of a temperate macrotidal ecosystem: combined morphological and molecular approaches.

Author

Pauline Bazin, Fabien Jouenne, Thomas Friedl, Anne-Flore Deton-Cabanillas, Bertrand Le Roy, and Benoît Véron

Subjects
Medicine, Science
Abstract

Microscopical and molecular analyses were used to investigate the diversity and spatial community structure of spring phytoplankton all along the estuarine gradient in a macrotidal ecosystem, the Baie des Veys (eastern English Channel). Taxa distribution at high tide in the water column appeared to be mainly driven by the tidal force which superimposed on the natural salinity gradient, resulting in a two-layer flow within the channel. Lowest taxa richness and abundance were found in the bay where Teleaulax-like cryptophytes dominated. A shift in species composition occurred towards the mouth of the river, with the diatom Asterionellopsis glacialis dramatically accumulating in the bottom waters of the upstream brackish reach. Small thalassiosiroid diatoms dominated the upper layer river community, where taxa richness was higher. Through the construction of partial 18S rDNA clone libraries, the microeukaryotic diversity was further explored for three samples selected along the surface salinity gradient (freshwater - brackish - marine). Clone libraries revealed a high diversity among heterotrophic and/or small-sized protists which were undetected by microscopy. Among them, a rich variety of Chrysophyceae and other lineages (e.g. novel marine stramenopiles) are reported here for the first time in this transition area. However, conventional microscopy remains more efficient in revealing the high diversity of phototrophic taxa, low in abundances but morphologically distinct, that is overlooked by the molecular approach. The differences between microscopical and molecular analyses and their limitations are discussed here, pointing out the complementarities of both approaches, for a thorough phytoplankton community description.

Published
2014
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2. Revision of the Genus Micromonas Manton et Parke (Chlorophyta, Mamiellophyceae), of the Type Species M. pusilla (Butcher) Manton & Parke and of the Species M. commoda van Baren, Bachy and Worden and Description of Two New Species Based on the Genetic and Phenotypic Characterization of Cultured Isolates

Author

Margot Tragin, Christophe Six, Yves Desdevises, Sophie Le Panse, Daniel Vaulot, Evelyne Derelle, Birger Marin, Daphné Grulois, Marie Latimier, Nathalie Simon, Dominique Marie, Elodie Foulon, Aude Houdan, Florence Le Gall, Fabien Jouenne, Diversité et Interactions au sein du Plancton Océanique (DIPO), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Procaryotes Phototrophes Marins = MArine Phototrophic Prokaryotes (MAPP), Biologie intégrative des organismes marins (BIOM), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Botanisches Institut, Universität zu Köln = University of Cologne, MArine Phototrophic Prokaryotes (MAPP), and Universität zu Köln

Subjects
0301 basic medicine, Species complex, Biology, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Microbiology, 03 medical and health sciences, Species Specificity, Chlorophyta, Genus, Botany, 14. Life underwater, Internal transcribed spacer, Clade, Phylogeny, Micromonas, Synapomorphy, Genome, Base Sequence, Phylogenetic tree, Pigments, Biological, RNA, Algal, biology.organism_classification, Type species, 030104 developmental biology, RNA, Ribosomal, Evolutionary biology, Sequence Alignment
Abstract

International audience; The green picoalgal genus Micromonas is broadly distributed in estuaries, coastal marine habitats and open oceans, from the equator to the poles. Phylogenetic, ecological and genomic analyses of culture strains and natural populations have suggested that this cosmopolitan genus is composed of several cryptic species corresponding to genetic lineages. We performed a detailed analysis of variations in morphology, pigment content, and sequences of the nuclear-encoded small-subunit rRNA gene and the second internal transcribed spacer (ITS2) from strains isolated worldwide. A new morphological feature of the genus, the presence of tip hairs at the extremity of the hair point, was discovered and subtle differences in hair point length were detected between clades. Clear non-homoplasious synapomorphies were identified in the small-subunit rRNA gene and ITS2 spacer sequences of five genetic lineages. These findings lead us to provide emended descriptions of the genus Micromonas, of the type species M. pusilla, and of the recently described species M. commoda, as well as to describe 2 new species, M. bravo and M. polaris. By clarifying the status of the genetic lineages identified within Micromonas, these formal descriptions will facilitate further interpretations of large-scale analyses investigating ecological trends in time and space for this widespread picoplankter.

Published
2017
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3. Phytoplankton community structure and primary production in small intertidal estuarine-bay ecosystem (eastern English Channel, France)

Author

Fabien Jouenne, Yvan Lagadeuc, Sébastien Lefebvre, Benoît Véron, Physiologie et Ecophysiologie des Mollusques Marins (PE2M), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre Armoricain de Recherche en Environnement (CAREN), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure Agronomique de Rennes-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), and Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-Ecole Nationale Supérieure Agronomique de Rennes-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Ecological succession, Aquatic Science, Biology, 01 natural sciences, Phytoplankton, Ecosystem, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Biomass (ecology), geography, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Estuary, 15. Life on land, biology.organism_classification, Oceanography, Diatom, 13. Climate action, Bloom, Bay
Abstract

FR2116; International audience; From May 2002 to October 2003, a fortnightly sampling programme was conducted in a restricted macrotidal ecosystem in the English Channel, the Baie des Veys (France). Three sets of data were obtained: (1) physico-chemical parameters, (2) phytoplankton community structure illustrated by species composition, biovolume and diversity, and (3) primary production and photosynthetic parameters via P versus E curves. The aim of this study was to investigate the temporal variations of primary production and photosynthetic parameters in this bay and to highlight the potential links with phytoplankton community structure. The highest level of daily depth-integrated primary production Pz (0.02–1.43 g C m–2 d–1) and the highest maximum photosynthetic rate PB max (0.39– 8.48 mg C mg chl a–1 h–1) and maximum light utilization coefficient aB [0.002–0.119 mg C mg chl a–1 h–1(lmol photons m–2 s–1)] were measured from July to September. Species succession was determined based on biomass data obtained from cell density and biovolume measurements. The bay was dominated by 11 diatoms throughout the year. However, a Phaeocystis globosa bloom (up to 25 mg chl a m–3, 2.5 · 106 cells l–1) was observed each year during the spring diatom bloom, but timing and intensity varied interannually. Annual variation of primary production was due to nutrient limitation, light climate and water temperature. The seasonal pattern of microalgal succession, with regular changes in composition, biovolume and diversity, influenced the physico-chemical and biological characteristics of the environment (especially nutrient stocks in the bay) and thus primary production. Consequently, investigation of phytoplankton community structure is important for developing the understanding of ecosystem functioning, as it plays a major role in the dynamics of primary production.

Published
2006
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4. Phytoplankton Diversity and Community Composition along the Estuarine Gradient of a Temperate Macrotidal Ecosystem: Combined Morphological and Molecular Approaches

Author

Anne-Flore Deton-Cabanillas, Pauline Bazin, Bertrand Le Roy, Thomas Friedl, Fabien Jouenne, Benoît Véron, Université de Rennes - Faculté des sciences pharmaceutiques et biologiques (UR Pharmacie), Université de Rennes (UR), Physiologie et Ecophysiologie des Mollusques Marins (PE2M), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Université de Rennes 1 - Faculté des sciences pharmaceutiques et biologiques (UR1 Pharmacie), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Lin, Senjie, Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), and Normandie Université (NU)-Normandie Université (NU)

Subjects
0106 biological sciences, Salinity, Climate, Biodiversity, lcsh:Medicine, Marine and Aquatic Sciences, Fresh Water, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 01 natural sciences, Water column, lcsh:Science, Phylogeny, ComputingMilieux_MISCELLANEOUS, Freshwater Ecology, 0303 health sciences, Multidisciplinary, geography.geographical_feature_category, biology, Ecology, Community structure, Temperature, Marine Ecology, Eukaryota, Biota, Community Ecology, France, Phytoplankton, Composition, Estuarine Gradient, Ecosystem, Estuaries, Ecosystem Functioning, Research Article, Freshwater Environments, DNA, Ribosomal, Ecosystems, Molecular Genetics, 03 medical and health sciences, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Rivers, RNA, Ribosomal, 18S, Genetics, Seawater, 14. Life underwater, Community Structure, 030304 developmental biology, Gene Library, geography, Brackish water, 010604 marine biology & hydrobiology, lcsh:R, fungi, Ecology and Environmental Sciences, Biology and Life Sciences, Aquatic Environments, Estuary, biology.organism_classification, Marine Environments, Clone Cells, Diatom, Earth Sciences, lcsh:Q, Species richness, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract

Microscopical and molecular analyses were used to investigate the diversity and spatial community structure of spring phytoplankton all along the estuarine gradient in a macrotidal ecosystem, the Baie des Veys (eastern English Channel). Taxa distribution at high tide in the water column appeared to be mainly driven by the tidal force which superimposed on the natural salinity gradient, resulting in a two-layer flow within the channel. Lowest taxa richness and abundance were found in the bay where Teleaulax-like cryptophytes dominated. A shift in species composition occurred towards the mouth of the river, with the diatom Asterionellopsis glacialis dramatically accumulating in the bottom waters of the upstream brackish reach. Small thalassiosiroid diatoms dominated the upper layer river community, where taxa richness was higher. Through the construction of partial 18S rDNA clone libraries, the microeukaryotic diversity was further explored for three samples selected along the surface salinity gradient (freshwater - brackish - marine). Clone libraries revealed a high diversity among heterotrophic and/or small-sized protists which were undetected by microscopy. Among them, a rich variety of Chrysophyceae and other lineages (e.g. novel marine stramenopiles) are reported here for the first time in this transition area. However, conventional microscopy remains more efficient in revealing the high diversity of phototrophic taxa, low in abundances but morphologically distinct, that is overlooked by the molecular approach. The differences between microscopical and molecular analyses and their limitations are discussed here, pointing out the complementarities of both approaches, for a thorough phytoplankton community description. peerReviewed

Published
2014
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5. Complex patterns in phytoplankton and microeukaryote diversity along the estuarine continuum

Author

Benoît Véron, Fabien Jouenne, Angel Pérez-Ruzafa, Anne-Flore Deton-Cabanillas, Pauline Bazin, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Université de Rennes - Faculté des sciences pharmaceutiques et biologiques (UR Pharmacie), Université de Rennes (UR), Physiologie et Ecophysiologie des Mollusques Marins (PE2M), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Universidad de Murcia, Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Université de Rennes 1 - Faculté des sciences pharmaceutiques et biologiques (UR1 Pharmacie), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS)

Subjects
Biodiversity, Aquatic Science, Biology, Microeukaryotes, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, Mediterranean sea, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Phytoplankton, 14. Life underwater, Microscopy, Diversity, Ecology, Estuarine gradient, Community structure, 18S rDNA clone libraries, 15. Life on land, Semiarid area, 6. Clean water, Spatial heterogeneity, Water Framework Directive, 13. Climate action, Species richness, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Eutrophication, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract

International audience; Estuaries and coastal lagoons are included within the transitional waters category, according to the Water Framework Directive. However, criteria for their differentiation and characterisation are still under discussion and require more research. In particular, detailed observations of biodiversity in more complex transitional and coastal waters are lacking. Microscopic and molecular analyses were therefore used to investigate phytoplankton diversity and spatial community structure, in early spring, along the freshwater-to-marine continuum of the Segura River (Spain), an intensively regulated semiarid basin discharging into the Mediterranean Sea. In addition to the salinity gradient as the major factor determining taxa distribution, influence of multiple anthropogenic and climatic impacting factors (drought, confined waters, irrigation canal) leads to a significant spatial heterogeneity of the aquatic habitat types associated with variations in community composition. Several shifts within the phytoplankton distribution pattern along the continuum are revealed using multivariate analyses. An impressive bloom of the cryptophyte Plagioselmis prolonga occurred in the mixing zone, associated with a typical euryhaline community indicative of eutrophication. The 18S rDNA diversity revealed a microeukaryotic richness including several little-known groups, heterotrophic representatives, and potential parasites. By combining morphological and molecular approaches we revealed the presence of a ‘hidden’ diversity often neglected in traditional surveys.

Published
2014
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6. Distribution of eukaryotic plankton in the English Channel and the North Sea in summer

Author

Corina P. D. Brussaard, Martial Ferréol, Daniel Vaulot, Sylvie Masquelier, Elodie Foulon, Fabien Jouenne, Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Biologie des écosystèmes aquatiques (UR BELY), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), Diversité et Interactions au sein du Plancton Océanique (DIPO), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Research Council for Earth and Life Sciences (ALW), Netherlands Organisation for Scientific Research (NWO), ``Ministere de la Culture, de l'Enseignement Superieur et de la Recherche' of Luxembourg [BFR05/027], and EU

Subjects
0106 biological sciences, [SDV]Life Sciences [q-bio], Chlorophyta, Aquatic Science, Oceanography, Haptophyta, 01 natural sciences, 18S ribosomal RNA, 03 medical and health sciences, Temperate climate, 14. Life underwater, Picoplankton, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology, Micromonas, 18S rRNA Probes, 0303 health sciences, Picoeukaryote, biology, Chlorophyta [green algae], Ecology, 010604 marine biology & hydrobiology, Micromonas pusilla, Plankton, biology.organism_classification, [SDE]Environmental Sciences, North Sea
Abstract

[Departement_IRSTEA]Eaux; International audience; The distribution of eukaryotic plankton was investigated in the English Channel and the North Sea during the MICROVIR cruise in summer 2007. The size distribution of autotrophic, heterotrophic eukaryotes and species composition was analyzed with a focus on two major divisions, Haptophyta and Chlorophyta, targeted by 18S rRNA probes. Picoeukaryotes (

Published
2011
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7. Prasinoderma singularis sp. nov. (Prasinophyceae, Chlorophyta), a solitary coccoid Prasinophyte from the South-East Pacific Ocean

Author

Florence Le Gall, Wenche Eikrem, Geir Johnsen, Dominique Marie, Daniel Vaulot, Fabien Jouenne, Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Diversité et Interactions au sein du Plancton Océanique (DIPO), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff [Roscoff] (SBR), Norwegian University of Science and Technology [Trondheim] (NTNU), Norwegian University of Science and Technology (NTNU), ANR [06-BDIV-013], Contrat de Projet Etat-Region ``Souchotheque de Bretagne', and EU [EU-RI-227799]

Subjects
0106 biological sciences, Prasinophyceae, [SDV]Life Sciences [q-bio], picoplankton, 01 natural sciences, Microbiology, 18S ribosomal RNA, 03 medical and health sciences, taxonomy, stomatognathic system, Phylogenetics, Chlorophyta, Botany, RNA, Ribosomal, 18S, 14. Life underwater, Genome size, Phylogeny, 030304 developmental biology, 0303 health sciences, field emission scanning electron microscopy (FE-SEM), Pacific Ocean, biology, 010604 marine biology & hydrobiology, Pigments, Biological, Ribosomal RNA, biology.organism_classification, humanities, Prasinoderma, binary fission, [SDE]Environmental Sciences, Ultrastructure, Taxonomy (biology), Genome, Plant
Abstract

International audience; During the BIOSOPE cruise in the South-East Pacific Ocean in 2004, several unidentified strains of prasinophytes were isolated into culture. Of these, nine strains composed a group for which the partial 18S rRNA gene sequence was related to Prasinoderma coloniale. The ultrastructure, morphology, division process, pigment composition, genome size and molecular genetic phylogeny of these nine strains were investigated, using P. coloniale as a reference. The 18S rRNA gene sequence of P. singularis sp. nov. shares only 96.9% of identity with that of P. coloniale and contains a conserved insertion of 567 bp length not recorded in P. coloniale. When compared to P. coloniale, P. singularis sp. nov. is morphologically characterized by the absence of colonies, smaller cells with a thinner cell wall, and a second cell type with a different cell covering. (C) 2010 Elsevier GmbH. All rights reserved.

Published
2009
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8. On the interest of using field primary production data to calibrate phytoplankton rate processes in ecosystem models

Author

Karine Grangeré, Fabien Jouenne, Sébastien Lefebvre, Alain Menesguen, Archéologie, Terre, Histoire, Sociétés [Dijon] ( ARTeHiS ), Ministère de la Culture et de la Communication ( MCC ) -Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d’écologie benthique, IFREMER, Adaptation et diversité en milieu marin ( ADMM ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Archéologie, Terre, Histoire, Sociétés [Dijon] (ARTeHiS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-Ministère de la Culture et de la Communication (MCC), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Ministère de la Culture et de la Communication (MCC)-Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Benthique Côtière (LEBCO), Dynamiques des Écosystèmes Côtiers (DYNECO), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)

Subjects
0106 biological sciences, Chlorophyll a, 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], Irradiance, Aquatic Science, Biology, Oceanography, Atmospheric sciences, Photosynthesis, Chlorophyll a to carbon ratio, 01 natural sciences, Baie des Veys, chemistry.chemical_compound, Ecosystem model, Phytoplankton, Calibration, Ecosystem, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Hydrology, Diatoms, [ SDV ] Life Sciences [q-bio], 010604 marine biology & hydrobiology, 15. Life on land, Exponential function, Normandy, chemistry, Empirical formulations, Photosynthesis irradiance curve, Mechanistic formulations, Parameter optimisation, France
Abstract

In many ecosystem models based on empirical formulations, parameters generally are calibrated in order to achieve the best fit between measured and simulated chlorophyll a standing stocks. An accurate calibration of rate processes as primary production rarely is taken into account. In this paper, we test the usefulness of calibration of phytoplankton photosynthetic processes in an ecosystem model using field primary production data. We used 18 months of photosynthetic process data from the Baie des Veys ecosystem (Normandy, France). Five empirical formulations of photosynthesis-irradiance curve models amongst the most widely used were tested. In each formulation, the variability of photosynthetic parameters (i.e. the light-saturated rate of photosynthesis (P-max(B)) and the initial slope of the. photosynthesis-light curve (alpha(B))) was considered depending on environmental factors (temperature and nutrient availability). The fit of the five equations as well as the calibration of parameters on field measurements (i.e. the light-saturated rate of photosynthesis (P-ref(B)), the initial slope of the photosynthesis-light curve (alpha(B)(ref)), the half-saturation constant for nitrogen (K-N) and silicates uptake (K-Si), and the coefficient in the exponential thermal effect (K-T)) was performed using the whole available data set of P vs. E curves (n = 143, P vs. E curves). Then, the Smith formulation allowing the best simulation of the Baie des Veys primary production and corresponding parameters were introduced in an ecosystem box model. This formulation led directly to a satisfactory representation of the Baie des Veys phytoplankton dynamics without additional calibration. Results obtained were compared with a more classical approach in which ecosystem models were calibrated using published values of parameters. This comparison showed that for the two years studied, annual primary production estimated through the ecosystem model was 13% and 26% higher with our approach than with the more classical approach. This work emphasizes the importance of accurately representing rate processes in ecosystem models in order to adequately simulate production as well as standing stocks. (C) 2008 Elsevier Ltd. All rights reserved.

Published
2009
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9. Biological and physicochemical factors controlling short-term variability in phytoplankton primary production and photosynthetic parameters in a macrotidal ecosystem (eastern English channel)

Author

Yvan Lagadeuc, Benoît Véron, Fabien Jouenne, Sébastien Lefebvre, Physiologie et Ecophysiologie des Mollusques Marins (PE2M), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Centre Armoricain de Recherche en Environnement (CAREN), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure Agronomique de Rennes-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), FR2116, Briand, Valerie, Université de Rennes (UR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-Ecole Nationale Supérieure Agronomique de Rennes-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Aquatic Science, Oceanography, Photosynthesis, 01 natural sciences, composition specifique, Phytoplankton, Ecosystem, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, phytoplancton, Ecology, 010604 marine biology & hydrobiology, Community structure, Species diversity, Estuary, production primaire, 15. Life on land, [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, macrotidal, variabilité, Environmental science, Bay, Channel (geography)
Abstract

Links between short-term variability of phytoplankton primary production and community structure changes have been studied rarely. This has been examined in a macrotidal ecosystem, the Baie des Veys (eastern English Channel, France), in 2003 and 2004, over the complete tidal cycle (semi-diurnal mode, 12 h). Within this area, primary production and photosynthetic parameter estimates, according to the 14C incorporation technique, were supported by an exhaustive taxonomic study and measurements of physicochemical factors to illustrate the environmental framework. Related to the river Vire discharge, daily interactions between estuarine and bay waters were demonstrated. Depth-integrated primary production Pz was maximal around noon in the bay (48.7–68.0 mg C m−2 h−1) and decreased through the day in the mouth of the river. Photosynthetic parameters' variations and photoacclimation were influenced by the ecosystem variability level: short-term photoacclimation was possible in low mixing conditions. Changes in taxonomic composition according to tidal forcing led to variations in primary production levels. Large species, associated with high photosynthetic parameters, were observed in the bay, whereas small ones were present in the mouth of the river, when low primary production was measured. On a short-time scale, a positive relationship was observed between species diversity and primary production. This work emphasizes the need to focus on changes in phytoplankton community structure in order to understand short-term variability in primary production.

Published
2005

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