Environmental conditions which lead to increase in cell density of the toxic dinoflagellates Dinophysis spp. in nutrient-rich and nutrient-poor waters of the French Atlantic coast

摘要: From 22 April to 19 June 1990, 7 stations located off La Rochelle, France, from near-shore ('bassin Marennes-Oleron') offshore waters (50 m depth contour) were visited 8 times, with the aim of determining whether toxic dinoflagellates Dinophysis spp. increase in cell density nutrient-poor water, nutrient-rich inshore waters, or both, and determine their vertical distribution relation stratification. Temperature stratification developed offshore, but not inshore. In April, few present none late May, up 15 X 10(3) cells l(-1) recorded 10 layer whereas contained only a l(-1). short period wind partly modified structure, concentration fell, increasing again when marked was established. Through strait, flood-tide currents moved area, ebb-tide brought some them back out. No relationship found between growth availability dissolved nutrients. We concluded that: (1) sufficient magnitude (DELTAt 5-degrees-C) duration ( 2 wk) are factors necessary for increase, (2) inorganic nutrient input terrestrial origin does directly promote growth.