Pyrodinium bahamense var. compressum Böhm Survival in High and Low Cadmium Levels

Pyrodinium bahamense var. compressum (Pbc) is a major public health concern particularly in the Southeast Asian region, and increasing threat brought by heavy metal pollution has greatly disturbed and altered the ecological balance of the region’s marine waters. Herein, we report the effect of cadmium, a biotoxic metal, to cell cultures of Pbc. Within 72 h after treatment with high cadmium concentration (50 ppm Cd2+), the cell density dramatically declined. Chlorophylls a and c2 also decreased after 30-day exposure. However, the low Cd2+ (1 ppm)-treated cells had comparable response to the untreated cultures. Thus, the organism’s ability to survive under low dose of cadmium implies a built-in stress response mechanism, but higher concentration is lethal to its survival and growth. The result of this study may lead to clearer insight on the role of metal ions in the growth and bloom dynamics of this important dinoflagellate.