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Auteur (down) Lopez-Joven, C.; Rolland, J.-L.; Haffner, P.; Caro, A.; Roques, C.; Carré, C.; Travers, M.-A.; Abadie, E.; Laabir, M.; Bonnet, D.; Destoumieux-Garzón, D.
Titre Oyster Farming, Temperature, and Plankton Influence the Dynamics of Pathogenic Vibrios in the Thau Lagoon Type Article scientifique
Année 2018 Publication Revue Abrégée Front. Microbiol.
Volume 9 Numéro Pages
Mots-Clés bivalve mollusks; mortality outbreak; Phytoplankton; Shellfish farming; Vibrio; Zooplankton
Résumé Vibrio species have been associated with recurrent mass mortalities of juvenile oysters Crassostrea gigas threatening oyster farming worldwide. However, knowledge of the ecology of pathogens in affected oyster farming areas remains scarce. Specifically, there are no data regarding (i) the environmental reservoirs of Vibrio populations pathogenic to oysters, (ii) the environmental factors favoring their transmission, and (iii) the influence of oyster farming on the persistence of those pathogens. This knowledge gap limits our capacity to predict and mitigate disease occurrence. To address these issues, we monitored Vibrio species potentially pathogenic to C. gigas in 2013 and 2014 in the Thau Lagoon, a major oyster farming region in the coastal French Mediterranean. Sampling stations were chosen inside and outside oyster farms. Abundance and composition of phyto-, microzoo-, and mesozooplankton communities were measured monthly. The spatial and temporal dynamics of plankton and Vibrio species were compared, and positive correlations between plankton species and vibrios were verified by qPCR on isolated specimens of plankton. Vibrio crassostreae was present in the water column over both years, whereas Vibrio tasmaniensis was mostly found in 2013 and Vibrio aestuarianus was never detected. Moreover, V. tasmaniensis and V. crassostreae were found both as free-living or plankton-attached vibrios one month after spring mortalities of the oyster juveniles. Overall, V. crassostreae was associated with temperature and plankton composition, whereas V. tasmaniensis correlated with plankton composition only. The abundance of Vibrio species in the water column was similar inside and outside oyster farms, suggesting important spatial dispersion of pathogens in surrounding areas. Remarkably, a major increase in V. tasmaniensis and V. crassostreae was measured in the sediment of oyster farms during cold months. Thus, a winter reservoir of pathogenic vibrios could contribute to their ecology in this Mediterranean shellfish farming ecosystem.
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Langue English Langue du Résumé Titre Original
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ISSN 1664-302x ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2438
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Auteur (down) Lezama-Ochoa, A.; Grados, D.; Lebourges Dhaussy, A.; Irigoien, X.; Chaigneau, A.; Bertrand, A.
Titre Biological characteristics of the hydrological landscapes in the Bay of Biscay in spring 2009 Type Article scientifique
Année 2015 Publication Revue Abrégée Fisheries Oceanography
Volume 24 Numéro 1 Pages 26-41
Mots-Clés acoustics; Bay of Biscay; Biogeography; fish; horizontal distribution; hydrological structures; macrozooplankton; patterns
Résumé In the present study we investigated the biogeography of macrozooplankton and fish biomass in the Bay of Biscay. In this region, we defined six different landscapes based on the hydrogeographical characteristics observed in spring 2009. We then related landscape's characteristics and environmental parameters such as light attenuation depth and chlorophyll-a with macrozooplankton and fish acoustic biomass. Hydrodynamic structures together with coastal influences (river discharges, predation pressure and depth preference) and vertical thermohaline structure/mixing (feeding modes and ability to stay in preferred layers) appeared as the main factors determining the biological distribution. Besides, variance partitioning was used to assess the respective roles played by the hydrological environment, the geographical space and the biological environment alone, and their interactions. Results revealed that: (i) macrozooplankton and fish have a preference for different hydrogeographical landscapes; (ii) the association between hydrological conditions and geographical features, i.e. the spatial structure of the hydrological environment, plays a key role in the distribution of macrozooplankton; and (iii) prey-predator relationships have to be taken into account to provide a comprehensive characterization of habitat suitability.
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Langue Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1054-6006 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1109
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Auteur (down) Leruste, A.; Villeger, S.; Malet, N.; De Wit, R.; Bec, B.
Titre Complementarity of the multidimensional functional and the taxonomic approaches to study phytoplankton communities in three Mediterranean coastal lagoons of different trophic status Type Article scientifique
Année 2018 Publication Revue Abrégée Hydrobiologia
Volume 815 Numéro 1 Pages 207-227
Mots-Clés classification; Classification; disturbance; diversity; ecology; Functional entity; Functional traits; lake phytoplankton; marine-phytoplankton; patterns; size; synechococcus; Taxonomic diversity; traits
Résumé We used the individual-based multidimensional functional diversity and the taxonomic approaches in a complementary way to describe phytoplankton communities in three coastal lagoons with different eutrophication status in the South of France. We sampled communities during three seasons, i.e., in autumn, spring, and summer. Using classical taxonomy, 107 taxa/morphotypes were identified in the nine communities. The individual-based functional approach allowed grouping these individuals into 20 functional entities according to their values for 5 traits related to trophic adaptations (cell size, mobility, trophic regime, coloniality, and pelagic/benthic life). Some species (e.g., Prorocentrum micans) emerged in multiple functional entities, showing the importance to consider intraspecific variability. The functional description of phytoplankton communities better reflected the hydrological functioning and the different eutrophication status of the lagoons than the taxonomic approach. Specific functional adaptations were identified in the nine communities. For example, phytoplankton organisms with heterotrophic and potentially mixotrophic abilities occurred when the availability of inorganic nutrient decreased, or when organic matter and small preys were potentially the main nutrient resources. The limitation has also favored small cells highly competitive for nutrients. Using functional indices together with taxonomic description has also helped revealing important aspects of community assembly, such as competitive exclusion in summer.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0018-8158 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2322
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Auteur (down) Leruste, A.; Malet, N.; Munaron, D.; Derolez, V.; Hatey, E.; Collos, Y.; De Wit, R.; Bec, B.
Titre First steps of ecological restoration in Mediterranean lagoons: Shifts in phytoplankton communities Type Article scientifique
Année 2016 Publication Revue Abrégée Estuarine, Coastal and Shelf Science
Volume 180 Numéro Pages 190-203
Mots-Clés Coastal lagoons; Nutrient; Phytoplankton; Re-oligotrophication; Sewage effluents
Résumé Along the French Mediterranean coast, a complex of eight lagoons underwent intensive eutrophication over four decades, mainly related to nutrient over-enrichment from continuous sewage discharges. The lagoon complex displayed a wide trophic gradient from mesotrophy to hypertrophy and primary production was dominated by phytoplankton communities. In 2005, the implementation of an 11 km offshore outfall system diverted the treated sewage effluents leading to a drastic reduction of anthropogenic inputs of nitrogen and phosphorus into the lagoons. Time series data have been examined from 2000 to 2013 for physical, chemical and biological (phytoplankton) variables of the water column during the summer period. Since 2006, total nitrogen and phosphorus concentrations as well as chlorophyll biomass strongly decreased revealing an improvement in lagoon water quality. In summertime, the decline in phytoplankton biomass was accompanied by shifts in community structure and composition that could be explained by adopting a functional approach by considering the common functional traits of the main algal groups. These phytoplankton communities were dominated by functional groups of small-sized and fast-growing algae (diatoms, cryptophytes and green algae). The trajectories of summer phytoplankton communities displayed a complex response to changing nutrient loads over time. While diatoms were the major group in 2006 in all the lagoons, the summer phytoplankton composition in hypertrophic lagoons has shifted towards green algae, which are particularly well adapted to summertime conditions. All lagoons showed increasing proportion and occurrence of peridinin-rich dinophytes over time, probably related to their capacity for mixotrophy. The diversity patterns were marked by a strong variability in eutrophic and hypertrophic lagoons whereas phytoplankton community structure reached the highest diversity and stability in mesotrophic lagoons. We observe that during the re-oligotrophication process in coastal lagoons, phytoplankton shows complex trajectories with similarities with those observed in freshwater lake systems.
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Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0272-7714 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1598
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Auteur (down) Leboulanger, C.; Agogué, H.; Bernard, C.; Bouvy, M.; Carré, C.; Cellamare, M.; Duval, C.; Fouilland, E.; Got, P.; Intertaglia, L.; Lavergne, C.; Floc’h, E.L.; Roques, C.; Sarazin, G.
Titre Microbial Diversity and Cyanobacterial Production in Dziani Dzaha Crater Lake, a Unique Tropical Thalassohaline Environment Type Article scientifique
Année 2017 Publication Revue Abrégée Plos One
Volume 12 Numéro 1 Pages e0168879
Mots-Clés Biomass (ecology); Cyanobacteria; Lakes; Oxygen; Phytoplankton; Ribosomal RNA; Sea water; Surface water
Résumé This study describes, for the first time, the water chemistry and microbial diversity in Dziani Dzaha, a tropical crater lake located on Mayotte Island (Comoros archipelago, Western Indian Ocean). The lake water had a high level of dissolved matter and high alkalinity (10.6–14.5 g L-1 eq. CO32-, i.e. 160–220 mM compare to around 2–2.5 in seawater), with salinity up to 52 psu, 1.5 higher than seawater. Hierarchical clustering discriminated Dziani Dzaha water from other alkaline, saline lakes, highlighting its thalassohaline nature. The phytoplankton biomass was very high, with a total chlorophyll a concentration of 524 to 875 μg chl a L-1 depending on the survey, homogeneously distributed from surface to bottom (4 m). Throughout the whole water column the photosynthetic biomass was dominated (>97% of total biovolume) by the filamentous cyanobacteria Arthrospira sp. with a straight morphotype. In situ daily photosynthetic oxygen production ranged from 17.3 to 22.2 g O2 m-2 d-1, consistent with experimental production / irradiance measurements and modeling. Heterotrophic bacterioplankton was extremely abundant, with cell densities up to 1.5 108 cells mL-1 in the whole water column. Isolation and culture of 59 Eubacteria strains revealed the prevalence of alkaliphilic and halophilic organisms together with taxa unknown to date, based on 16S rRNA gene analysis. A single cloning-sequencing approach using archaeal 16S rDNA gene primers unveiled the presence of diverse extremophilic Euryarchaeota. The water chemistry of Dziani Dzaha Lake supports the hypothesis that it was derived from seawater and strongly modified by geological conditions and microbial activities that increased the alkalinity. Dziani Dzaha has a unique consortium of cyanobacteria, phytoplankton, heterotrophic Eubacteria and Archaea, with very few unicellular protozoa, that will deserve further deep analysis to unravel its uncommon diversity. A single taxon, belonging to the genus Arthrospira, was found responsible for almost all photosynthetic primary production.
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Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1932-6203 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 1702
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