Abstract: The ecotoxicological and biochemical study withHeterosigma akashiwo, Alexandrium tamarense and Skeletonema costatum showed that the test three species of red-tide microalgae had different sensitivities to UVB radiation enhancement,and the order from high to low was Heterosigma akashiwo, Alexandrium tamarense and Skeletonema costatum.The DNA damage of algal cells increased with UV-B radiation enhancement,being more notable in Heterosigma akashiwo than in Alexandrium tamarenseand Skeletonema costatum,and in Alexandrium tamarensethan in Skeletonema costatum.The DNA damage of Heterosigma akashiwo and Alexandrium tamarense could be significantly repaired (P<0.05) after 6 days of UV-B radiation removal,and that of Skeletonema costatum could be significantly repaired (P<0.05) after 3 days,which illustrated that the DNA damage of three red-tide microalgae species could not indicate the damaged degree of marine microalgae resulted from UV-B radiation enhancement.

Key words: Wetland, Algae ecology