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| Perrot, Laurie; Gohin, Francis; Ruiz-pino, Diana; Lampert, Luis; Huret, Martin; Dessier, Aurelie; Malestroit, Pascale; Dupuy, Christine; Bourriau, Paul. |
| Coccolithophore blooms occur regularly from April to June in the Bay of Biscay where they have been observed for many years from ocean-colour imagery thanks to the ability of their calcite plates to scatter light. They are easily depicted on interpolated images of non-algal Suspended Particulate Matter (SPM) derived from satellite reflectance data in May, at the time of the PELGAS (PELagique GAScogne) annual surveys. Over the springs 2012 to 2015, the PELGAS surveys provided in-situ data on the turbidity throughout the water column and on the hydrological environment prevailing during the blooms in the vicinity of the continental shelf break. The satellite-derived SPM in the area of coccolithophore blooms was closely related to measured turbidity in the... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Ocean colour; Suspended particulate matter; Turbidity; Coccoliths; Stratification. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00416/52790/53689.pdf |
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| Chapelle, Annie; Le Bec, Claude; Amzil, Zouher; Dreanno, Catherine; Guillou, Laure; Klouch, Khadidja; Labry, Claire; Le Gac, Mickael; Pineau-guillou, Lucia; Siano, Raffaele; Abernot, Chantal; Andrieux, Francoise; Caradec, Florian; Destombe, Christophe; Dia, A.; Doner, Anne; Duval, Julia; Gouriou, Jeremie; Lazure, Pascal; Le Brun, Luc; Le Gal, Dominique; Malestroit, Pascale; Petton, Sebastien; Plus, Martin; Quere, Julien; Savar, Veronique; Schmitt, Sophie; Terre, A.; Youenou, Agnes. |
| Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été élaboré avec la Région Bretagne dans le cadre du développement du port de Brest. L’Ifremer a organisé un échantillonnage dans l’estuaire de la rivière de Daoulas, zone la plus touchée en 2012, au cours des printemps-été 2013 et 2014. Un suivi de la présence d’A. minutum dans les sédiments a également été réalisé en hiver 2014. De ces suivis, des mesures réalisées au laboratoire à ce jour, des simulations du modèle Prévimer ainsi que des résultats du réseau Rephy et Velyger, il ressort que: * La rade de Brest peut aujourd’hui être considérée comme une zone à risque pour Alexandrium minutum. En effet, depuis 2012... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00254/36487/35029.pdf |
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| Le Gac, Mickael; Metegnier, Gabriel; Chomerat, Nicolas; Malestroit, Pascale; Quere, Julien; Bouchez, Olivier; Siano, Raffaele; Destombe, Christophe; Guillou, Laure; Chapelle, Annie. |
| Understanding divergence in the highly dispersive and seemingly homogeneous pelagic environment for organisms living as free drifters in the water column remains a challenge. Here, we analyzed the transcriptome wide mRNA sequences, as well as the morphology of 18 strains of Alexandrium minutum, a dinoflagellate responsible for Harmful Algal Blooms worldwide, to investigate the functional bases of a divergence event. Analysis of the joint site frequency spectrum (JSFS) pointed toward an ancestral divergence in complete isolations followed by a secondary contact resulting in gene flow between the two diverging groups, but heterogeneous across sites. The sites displaying fixed SNPs were associated with a highly restricted gene flow and a strong... |
| Tipo: Text |
Palavras-chave: Dinoflagellates; Harmful algal blooms; Populations Genomics; Pseudocryptic species; Speciation. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00347/45857/45529.pdf |
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| Lemee, R; Boudouresque, Cf; Gobert, J; Malestroit, Pascale; Mari, X; Meinesz, A; Menager, V; Ruitton, S. |
| Experiments in aquaria have shown that the feeding behaviour of the sea urchin Paracentrotus lividus in presence of the green alga Caulerpa taxifolia varies during the year. In summer, the alga is strongly avoided and is not consumed. in winter and spring, although the alga is only moderately appreciated, its consumption is significant, but it is hardly or not at all absorbed. These results are confirmed by content analysis of the digestive tract of P. lividus sampled in situ in an area colonized by C. taxifolia. The sea urchins' feeding behaviour is linked to the presence of toxic and repellent secondary metabolites of C. taxifolia, caulerpenyne in particular. |
| Tipo: Text |
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| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00094/20483/18153.pdf |
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| Ganteaume, A; Gobert, J; Malestroit, Pascale; Menager, V; Francour, P; Boudouresque, Cf. |
| In vitro short time experiments (a few weeks) show that daily ingestion by Paracentrotus lividus (Echinodermata: Echinoidea) is weak (0-81 mg DW d(-1) ind(-1)) for Caulerpa taxifolia (Chlorophyta), compared to the data recorded with an almost totally avoided brown alga, Cystoseira compressa (24-137 mg DW d(-1) ind(-1)) and with a preferred brown alga, Halopteris scoparin (79-397 mg DW d(-1) ind(-1)). There is no significant difference between spring (when the toxic metabolite content is at its minimum) and summer-autumn (when it is at its maximum). In contrast, the absorption rate of the sea urchin fed on Caulerpa taxifolia is significantly weaker in spring than in summer-autumn. Overall, the daily absorbed weight is negative in spring with C. taxifolia... |
| Tipo: Text |
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| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00210/32132/30589.pdf |
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| Malestroit, Pascale; Piquet, Jean-come; Kantin, Roger. |
| Dans le cadre de la contractualisation Ifremer / SRC intitulée « Actions de l'Ifremer au profit de la Section Régionale Conchylicole de Marennes-Oléron (année 2001) », l'action 3 prévoit le suivi de la reproduction de la moule (Mytilus edulis) et de l'huître (Crassostrea gigas) dans le bassin de Marennes-Oléron. Son but est triple : ~ détecter les émissions larvaires, ~ suivre dans le temps le devenir des cohortes de larves, ~ permettre la fourniture des informations aux professionnels. Pendant la saison 2001, des pêches de larves de moules ont été réalisées au point <<Boyard», à la demande des mytiliculteurs. En outre, afin d'informer les ostréiculteurs, des pêches de larves d'huîtres ont été effectuées aux points « Coux », « les Faulx », « les... |
| Tipo: Text |
Palavras-chave: Marennes Oléron; Captage; Larves; Crassostrea gigas; Huîtres; Mytilus edulis; Moules; Reproduction. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/rapport-6570.PDF |
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