In-situ microcosms, a tool for assessment of pesticide impacts on oyster spat (Crassostrea gigas)

Abstract : Effects of the herbicide Basamais (bentazon) and the fungicide Opus (epoxiconazole) on oyster spat (Crassostrea gigas) were assessed using in-situ microcosms in a field experiment lasting 13 days. Six-week-old hatchery spat (mean size 1.1 mm), previously collected on PVC plates, was immersed in glass bottles filled with 200 mu m filtered seawater. Bottles were maintained underwater at 6 m depth and their water content changed every other day. Growth, measured as shell area index increase, was 126 +/- 4% in the control bottles. While no growth differences were observed between control and individual pesticide treatments at 10 mu g l(-1), oysters treated with a mix of 10 mu g l(-1) Opus and 10 mu g l(-1) Basamais showed a 50% growth reduction compared with the control (P < 0.0001), suggesting a synergistic effect of these contaminants. Laboratory controls in microcosms maintained in a water bath with filtered natural light, were not significantly different from in-situ microcosm controls in the field, for organic weight content or growth. This in-situ experiment in microcosms allowed us to conclude that: (1) oyster spat can achieve significant growth in bottles immersed in situ without supplementary food; (2) this microcosm system is reliable and easy to use for environmental toxicity tests with C. gigas spat; (3) such microcosm systems can also be run in a laboratory water bath instead of more technically difficult immersed field experiments; (4) the synergistic effect observed here, at a concentration simulating a peak agricultural runoff event, suggests that the impacts of pesticides could be a real threat for oysters in estuarine areas.
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Ecotoxicology, Springer Verlag, 2008, 17 (4), pp.235-245. 〈10.1007/s10646-007-0190-9〉
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http://hal.univ-brest.fr/hal-00675562
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Soumis le : jeudi 1 mars 2012 - 14:25:54
Dernière modification le : mercredi 21 mars 2018 - 16:08:05

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Sabine Stachowski-Haberkorn, Françoise Quiniou, Morgane Nedelec, René Robert, Gwendolina Limon, et al.. In-situ microcosms, a tool for assessment of pesticide impacts on oyster spat (Crassostrea gigas). Ecotoxicology, Springer Verlag, 2008, 17 (4), pp.235-245. 〈10.1007/s10646-007-0190-9〉. 〈hal-00675562〉

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