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| Labry, Claire; Erard-le Denn, Evelyne; Chapelle, Annie; Fauchot, Juliette; Youenou, Agnes; Crassous, Marie-pierre; Le Grand, Jacqueline; Lorgeoux, Benedicte. |
| The understanding of the dominance of one species with respect to others is a pertinent challenge in HAB growth dynamics studies and the nutrient supply mode is one of the factors potentially involved. The competition for phosphorus (P) between a toxic species, Alexandrium minutum, and a non-toxic species, Heterocapsa triquetra, was studied (1) along a gradient of P depletion, (2) testing different P depletion degrees before a single PO4 supply and (3) experimenting different PO4 supply frequencies. In conditions Of PO4 depletion, H. triquetra stopped growing after two days both in monospecific and mixed batch cultures whereas A. minutum grew progressively from day 2 until the end of the experiment. This time-lag growth of A. minutum is associated to its... |
| Tipo: Text |
Palavras-chave: Semi continuous culture; Batch culture; Ecophysiology; Pulse; Phosphorus storage; Dinoflagellates; Heterocapsa triquetra; Alexandrium minutum. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4067.pdf |
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| Sauvey, Aurore; Claquin, Pascal; Le Roy, Bertrand; Le Gac, Mickael; Fauchot, Juliette. |
| We used a multi‐strain approach to study the intra‐ and interspecific variability of the growth rates of three Pseudo‐nitzschia species – P. australis, P. fraudulenta, and P. pungens – and of their domoic acid (DA) production. We carried out mating and batch experiments to investigate the respective effects of strain age and cell size, and thus the influence of their life cycle on the physiology of these species. The cell size ‐ life cycle relationship was characteristic of each species. The influence of age and cell size on the intraspecific variability of growth rates suggests that these characteristics should be considered cautiously for the strains used in physiological studies on Pseudo‐nitzschia species. The results from all three species do not... |
| Tipo: Text |
Palavras-chave: Cell size; Domoic acid; Growth; Life cycle; Pseudo-nitzschia strains. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00505/61679/65622.pdf |
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| Lema, Anais Kimberley; Latimier, Marie; Nezan, Elisabeth; Fauchot, Juliette; Le Gac, Mickael. |
| The factors responsible for inducing the synthesis of toxins and responses from toxic phytoplankton blooms remain unclear. In this study we compare the influence of genotypic (at both the intra and interspecific levels) and environmental factors (nutrient concentration and ratio) on growth (in terms of cell densities) and domoic acid (DA) production in three Pseudo-nitzschia species: P. australis, P.pungens and P.fradulenta. A strong phosphate effect was detected. More precisely, a low initial concentration in phosphate, even at high initial nitrogen and silicate concentrations, induced the highest DA concentrations and the lowest cell densities in all strains/species studied. In contrast, a low initial concentration of nitrogen and silicate combined, with... |
| Tipo: Text |
Palavras-chave: Pseudo-nitzschia strains; Domoic acid; Ratio; Phosphate; Nitrogen. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00377/48849/49397.pdf |
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| Lema, Anais Kimberley; Metegnier, Gabriel; Quéré, Julien; Latimier, Marie; Youenou, Agnes; Lambert, Christophe; Fauchot, Juliette; Le Gac, Mickael. |
| Untangling the functional basis of divergence between closely related species is a step towards understanding species dynamics within communities at both the evolutionary and ecological scales. We investigated cellular (i.e: growth, domoic acid production, nutrient consumption) and molecular (transcriptomic analyses) responses to varying nutrient concentrations across several strains belonging to three species of the toxic diatom genus Pseudo-nitzschia. Three main results were obtained. First, strains from the same species displayed similar transcriptomic, but not necessarily cellular, responses to the experimental conditions. It showed the importance of considering intra-specific diversity to investigate functional divergence between species. Second, a... |
| Tipo: Text |
Palavras-chave: Phenotype; Transcriptomics; Pseudo-nitzschia; Divergence; Nutrients. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00482/59392/62157.pdf |
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| Foucher, Eric; Blanchard, Michel; Cugier, Philippe; Desroy, Nicolas; Dreanno, Catherine; Fauchot, Juliette; Fifas, Spyros; Guyader, Olivier; Jean, Frederic; Le Gallic, Bertrand; Riou, Philippe; Schapira, Mathilde; Thiebaut, Eric. |
| The King scallop Pecten maximus constitutes the first landed species in terms of tonnage and the second or third one in terms of value for the French fisheries. More than 90% of these landings come from the English Channel indicating that its exploitation is essential to local fleets. The COMANCHE project (Ecosystem Interactions and anthropogenic impacts on King scallops populations in the English Channel) proposed to improve the knowledge of the scallop within the Channel, through an ecosystem-based approach for fisheries, appealing to a wide range of scientific disciplines (physics, chemistry, genetics, ecology, geostatistics, modeling, economics ....). Researches on the spatial location of scallop beds, connectivity by larval dispersal between beds,... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00251/36236/34797.pdf |
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