%0 Journal Article %J Harmful Algae %D 2017 %T Nutrient ratios influence variability in Pseudo-nitzschia species diversity and particulate domoic acid production in the Bay of Seine (France) %A Thorel, Maxine %A Pascal Claquin %A Mathilde Schapira %A Romain Le Gendre %A Riou, Philippe %A Didier Goux %A Bertrand Le Roy %A Raimbault, V %A Deton-Cabanillas, A.-F. %A Bazin, Pauline %A Kientz-Bouchart, Valérie %A Juliette Fauchot %K analogs and derivatives %K analysis %K Bay %K Bays %K Biodiversity %K chemistry %K Diatom %K Diatoms %K Domoic acid %K France %K Geography %K kainic acid %K Nitrates %K nitric acid derivative %K particulate matter %K phosphate %K Phosphates %K Physiology %K Phytoplankton %K Principal Component Analysis %K season %K Seasons %K species difference %K Species Specificity %K time factor %K Time Factors %X 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 (∼1400 ng l−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. © 2017 Elsevier B.V. %B Harmful Algae %I Elsevier B.V. %V 68 %P 192-205 %G eng %U https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028543709&doi=10.1016%2fj.hal.2017.07.005&partnerID=40&md5=def23b37b0d16a1ae7ab65a7ef2b940b %R 10.1016/j.hal.2017.07.005 %0 Journal Article %J Harmful Algae %D 2017 %T Nutrient ratios influence variability in Pseudo-nitzschia species diversity and particulate domoic acid production in the Bay of Seine (France) %A Thorel, Maxine %A Pascal Claquin %A Mathilde Schapira %A Romain Le Gendre %A Riou, Philippe %A Goux, Didier %A Le Roy, Bertrand %A Raimbault, V %A Deton-Cabanillas, Anne-Flore %A Bazin, Pauline %A Kientz-Bouchart, Valérie %A Juliette Fauchot %K Bloom dynamics %K Domoic acid %K English Channel %K Nutrient ratios %K Pseudo-nitzschia Species diversity %X

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 (∼1400 ng l−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.

%B Harmful Algae %V 68 %P 192 - 205 %G eng %U http://www.sciencedirect.com/science/article/pii/S1568988317300148 %R https://doi.org/10.1016/j.hal.2017.07.005 %0 Journal Article %J Aquat Toxicol %D 2014 %T Effects of acute exposures to mecoprop, mecoprop-p and their biodegradation product (2-MCP) on the larval stages of the Pacific oyster, Crassostrea gigas. %A Mottier, A %A Kientz-Bouchart, Valérie %A Dubreule, Christelle %A Antoine Serpentini %A Jean-Marc Lebel %A Katherine Costil %K 2-Methyl-4-chlorophenoxyacetic Acid %K Animals %K Chlorophenols %K Crassostrea %K Embryo, Nonmammalian %K Larva %K Metamorphosis, Biological %K Water Pollutants, Chemical %X

Studies have shown that pesticides are sometimes detected at rather high levels in seawater and it has been suggested that these chemical compounds could act as additional stress factor for oysters cultured in coastal environments. The effects of pesticides on marine molluscs could be particularly harmful in the early stages which correspond to critical life stages. This study aimed to assess the effects of mecoprop, mecoprop-p and their degradation compound 2-methyl-4-chlorophenol on two larval stages of Crassostrea gigas. Embryotoxic effects were assessed on veliger larvae after 36 h exposures, and both percentages of normal larvae and types of abnormalities were taken into account. The effects of the three substances were evaluated on 21-day-old pediveliger larvae by calculating metamorphosis rates after 24h exposures. The results of the embryotoxicity assay indicated that 2-methyl-4-chlorophenol was more toxic (EC50: 10.81 mg L(-1)) than its parent compounds (EC50 mecoprop: 42.55 mg L(-1); EC50 mecoprop-p: 78.85 mg L(-1)). Mecoprop in particular injured shell formation with an increase of shell abnormalities following herbicide concentrations. The active substances were not toxic to metamorphosis processes, but 2-MCP was revealed to be more toxic to the success of metamorphosis (EC50: 7.20 mg L(-1)) than to embryo-larval development. However, the toxic concentrations were several orders of magnitude higher than environmental concentrations.

%B Aquat Toxicol %V 146 %P 165-75 %8 2014 Jan %G eng %R 10.1016/j.aquatox.2013.11.008