title: Relationship between valve activity, microalgae concentration in the water and toxin accumulation in the digestive gland of the Pacific oyster Crassostrea gigas exposed to Alexandrium minutum.
abstract: The complexity of the relationships between Alexandrium minutum (A.m.) concentration in the water ([A.m.](w)), Paralytic Shellfish Poisoning contamination in the digestive gland ([PSP](dg)) and valve behavior was explored in oysters Crassostrea gigas. Two experiments were conducted, during which oysters' valve behaviour were analyzed. Oysters, first acclimated for 10-days with the non harmful microalgae Heterocapsa triquetra (H.t.), were exposed to four microalgae mixtures at constant total concentrations of 10×10(3)cells ml(-1) (experiment-1) and 5×10(3)cells ml(-1) (experiment-2): 100% A.m.; 50% A.m.-50% H.t.; 25% A.m.-75% H.t.; 100% H.t. At the end of experiment-2, [PSP](dg) were measured. At 10×10(3)cells ml(-1), the microalgal ingestion decreased (p<0.05) with increasing [A.m.](w) but not at 5×10(3)cells ml(-1) (p>0.05). The frequency of microclosures specifically increased with [A.m.](w) (p<0.05) and the opening duration with [PSP](dg) (p<0.0001). Oysters exhibiting the maximum increase in opening duration also exhibited the highest [PSP](dg). The results are discussed in terms of oyster physiology and origin of the behavioral response.
authors.affiliation: Laboratoire des Sciences de l'Environnement Marin, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Place Copernic, Technopôle Brest-Iroise, 29280 Plouzané, France.
authors.forename: Hansy
authors.initials: H
authors.lastname: Haberkorn
authors.forename: Damien
authors.initials: D
authors.lastname: Tran
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Massabuau
authors.forename: Pierre
authors.initials: P
authors.lastname: Ciret
authors.forename: Véronique
authors.initials: V
authors.lastname: Savar
authors.forename: Philippe
authors.initials: P
authors.lastname: Soudant
mesh_terms: D000818:Animals; D049896:Crassostrea / Q000378:metabolism*; D004064:Digestive System / Q000378:metabolism*; D004141:Dinoflagellida / Q000302:isolation & purification* / Q000472:pathogenicity; D004784:Environmental Monitoring; D057097:Harmful Algal Bloom; D008387:Marine Toxins / Q000378:metabolism*; D012623:Seawater / Q000737:chemistry / Q000469:parasitology*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D008387:Marine Toxins; D014874:Water Pollutants, Chemical