The repetitive and expanding occurrence of a green, bloom-forming dinoflagellate (Dinophyceae) on the coasts of France

A dinoflagellate has produced green-water events along the Atlantic and English Channel coasts of France since 1982. It differs morphologically from each of the 12 taxa or so of green gymnodinoid dinoflagellates previously known. As some morphological details, as well as their variability, remain to be ascertained, this organism is illustrated and described here under the provisional designation of Gymnodinium "sp. 1982". The presence of chlorophyll b has been confirmed by HPLC analysis but it could not be ascertained whether true chloroplasts are present, or symbionts. The distribution is coastal and estuarine. The number and intensity of the outbreaks may be related to river runoff and to the amount of preceding rainfall. An encysted stage is described. Some noxious, presumably indirect, effects have been reported.