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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. Microbial parasites make cyanobacteria blooms less of a trophic dead end than commonly assumed

Author

Jonathan Colombet, Matilda Haraldsson, Pauline Bazin, Samuele Tecchio, Nathalie Niquil, Télesphore Sime-Ngando, Mélanie Gerphagnon, 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), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)-Université d'Auvergne - Clermont-Ferrand I (UdA), 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), Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes - Faculté des sciences pharmaceutiques et biologiques (UR Pharmacie), and Université de Rennes (UR)

Subjects
0106 biological sciences, 0301 basic medicine, Cyanobacteria, Food Chain, Ecosystem ecology, [SDE.MCG]Environmental Sciences/Global Changes, education, 01 natural sciences, Microbiology, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Article, Microbial ecology, 03 medical and health sciences, Food chain, Phytoplankton, Animals, Ecosystem, Biomass, Fungal ecology, Ecology, Evolution, Behavior and Systematics, Trophic level, 2. Zero hunger, Biomass (ecology), biology, Ecology, 010604 marine biology & hydrobiology, Virus–host interactions, biology.organism_classification, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Food web, 030104 developmental biology, 13. Climate action
Abstract

International audience; Parasites exist in every ecosystem and can have large influence on food web structure and function, yet, we know little about parasites’ effect on food web dynamics. Here we investigate the role of microbial parasitism (viruses of bacteria, phytoplankton and cyanobacteria, and parasitic chytrids on cyanobacteria) on the dynamics of trophic pathways and food web functioning during a cyanobacteria bloom, using linear inverse food web modeling parameterized with a 2-month long data set (biomasses, infection parameters, etc.). We show the importance of grazing on heterotrophic bacteria (the microbial pathway: DOC → bacteria → consumer) and how consumers depended on bacteria during peak-cyanobacteria bloom, which abundance was partly driven by the viral activity. As bacteria become the main energy pathway to the consumers, the system takes a more web-like structure through increased omnivory, and may thereby facilitate the system’s persistence to the cyanobacteria outbreak. We also showed how the killing of cyanobacteria host cells by chytrids had important impact on the food web dynamics by facilitating grazing on the cyanobacteria, and by offering alternative pathways to the consumers. This seemed to increase the system’s ability to return to a mix of trophic pathways, which theoretically increases the stability of the system.

Published
2018

3. Nutrient ratios influence variability in Pseudo-nitzschia species diversity and particulate domoic acid production in the Bay of Seine (France)

Author

Pauline Bazin, Bertrand Le Roy, Juliette Fauchot, Romain Le Gendre, Didier Goux, Philippe Riou, Pascal Claquin, Mathilde Schapira, Maxine Thorel, Anne-Flore Deton-Cabanillas, Virginie Raimbault, Valérie Kientz-Bouchart, Biologie des mollusques marins et des écosystèmes associés (BioMEA), Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Sorbonne Université (SU)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut de Recherche pour le Développement (IRD), IFREMER LEAD-NC, Laboratoire Environnement et Ressources de Normandie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Interactions Cellules Organismes Environnement (ICORE), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-CHU Caen, Normandie Université (NU)-Tumorothèque de Caen Basse-Normandie (TCBN)-Tumorothèque de Caen Basse-Normandie (TCBN), Chirurgie digestive et hépatobiliaire, Centre Hospitalier Universitaire Estaing, Institut Pascal - Clermont Auvergne (IP), Sigma CLERMONT (Sigma CLERMONT)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), 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), Centre de Microscopie Appliquée à la Biologie [Caen] (CMABio3), Normandie Université (NU)-Tumorothèque de Caen Basse-Normandie (TCBN)-Tumorothèque de Caen Basse-Normandie (TCBN)-Université de Caen Normandie (UNICAEN), LABÉO, Pôle d’analyses et de recherche de Normandie (LABÉO), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), ODE/LITTORAL/LERN, Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER), CHU Estaing [Clermont-Ferrand], Institut de biologie de l'ENS Paris (UMR 8197/1024) (IBENS), Département de Biologie - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), 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), Normandie Université (NU), and Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Time Factors, 010504 meteorology & atmospheric sciences, Plant Science, 01 natural sciences, chemistry.chemical_compound, Nutrient, English channel, ComputingMilieux_MISCELLANEOUS, Species diversity, education.field_of_study, Principal Component Analysis, Kainic Acid, Geography, Ecology, Domoic acid, Biodiversity, Bloom dynamics, Spring bloom, Bays, Environmental chemistry, [SDE]Environmental Sciences, France, Seasons, Bloom, [SDE.MCG]Environmental Sciences/Global Changes, Population, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Aquatic Science, Biology, Phosphates, Species Specificity, 14. Life underwater, education, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 0105 earth and related environmental sciences, Diatoms, Nitrates, 010604 marine biology & hydrobiology, biology.organism_classification, Nutrient ratios, chemistry, Phytoplankton, Pseudo-nitzschia, Particulate Matter, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay
Abstract

International audience; The population dynamics of different Pseudo-nitzschia species, along with particulate domoic acid (pDA) concentrations, were studied from May 2012 to December 2013 in the Bay of Seine (English Channel, Normandy). While Pseudo-nitzschia spp. blooms occurred during the two years of study, Pseudo-nitzschia species diversity and particulate domoic acid concentrations varied greatly. In 2012, three different species were identified during the spring bloom (P. australis, P. pungens and P. fraudulenta) with high pDA concentrations (similar to 1400 ngl(-1)) resulting in shellfish harvesting closures. In contrast, the 2013 spring was characterised by a P. delicatissima bloom without any toxic event. Above all, the results show that high pDA concentrations coincided with the presence of P. australis and with potential silicate limitation (Si: N < 1), while nitrate concentrations were still replete. The contrasting environmental conditions between 2012 and 2013 highlight different environmental controls that might favour the development of either P. delicatissima or P. australis. This study points to the key role of Pseudo-nitzschia diversity and cellular toxicity in the control of particulate domoic acid variations and highlights the fact that diversity and toxicity are influenced by nutrients, especially nutrient ratios. (C) 2017 Elsevier B.V. All rights reserved.

Published
2017

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

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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