Effects of Irradiance on the Growth of the Toxic Dinoflagellates Alexandrium tamarense and Alexandrium catenella
The effects of irradiance on the growth of toxic dinoflagellates Alexandrium tamarense (Masan Bay strain) and Alexandrium catenella (Jinhae Bay strain) were investigated in the laboratory. At 15℃ and 30 psu for A. tamarense and 25℃ and 30 psu for A. catenella, the irradiance-growth curve showed the maximum growth rate (μmax) of 0.31 day-1 with half-saturation photon flux density (PFD) (KI) of 44.53 μmol m-2 s-1, and a compensation PFD (Ic) was 20.67 μmol m-2 s-1 for A. tamarense, and μmax of 0.38 day-1 with KI of 59.53 μmol m-2 s-1, and Ic was 40.80 μmol m-2 s-1 for A. catenella. The Ic equated to a depth of 8~9 m from March to June for A. tamarense and 6~7 m from March to June for A. catenella. These responses suggested that irradiance at the depth near the middle layer in Masan Bay would provide favorable conditions for two species.