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(M/EH031) Biomonitoring of seawater quality in situ using bivalve embryos. Geffard, Olivier 1, His, Edouard1, Budzinski, Hélène 2, Seaman, Matthias3, Garrigues, Philippe2, 1 2 3 ABSTRACT- Embryos and larvae of bivalves are frequently used in marine ecotoxicology for the purpose of assessing seawater quality, because they are very sensitive to pollutants and provide rapid results. Laboratory studies, however, can not accurately reproduce natural conditions. We conducted embryo-larval studies in situ at the marina of Arcachon (South West French Atlantic coast), in order to assess the "biological quality" of the water. Different materials were tested first to avoid any toxicity of the containers and glue to the bivalve larvae. Four series of experiments were subsequently performed during the summer of 2000 (ambient water temperatures of 22 to 24°C) with embryos of oysters, Crassostrea gigas. The results show that the "biological quality" of the water deteriorates from the port entrance towards its inner sector. One experiment conducted in the winter of 2000 (temperatures of 10 to 11°C) with embryos of mussels, Mytilus galloprovincialis, has shown that such tests equally practicable at low temperatures. This study did not show any deterioration in "biological quality of the water. To our knowledge, this is the first investigation of the marine environment in which invertebrate embryos have been used in situ. Using developmental stages in this type of study is advantageous, because they are more sensitive to pollutants than the adults. Key words: in situ, Embryo-larval bioassays, Crassostrea gigas, Seawater quality |
