Effects of sub-lethal UV-C irradiation on the growth of Microcystis aeruginosa

Microcystis aeruginosa is a typical bloom forming species in China waters.This study investigates the suppression of the algae growth by sub-lethal Ultraviolet-C(UV-C) irradiation.The algae were exposed to UV-C irradiation using a collimated beam apparatus and then sampled to determine the cell density using a confocal laser scanning microscope,the membrane integrity using flow cytometry,and the relative fluorescence level of phycocyanin and Chl a using a three-dimensional excitation-emission matrix analysis.The results show that UV-C irradiation at 50~100 mJ/cm2 suppresses M.aeruginosa growth of 106 cells/mL for 7 days and the suppression effect is sub-lethal to the cells.