Toxicity studies of tetracycline on Microcystis aeruginosa and Selenastrum capricornutum

The assays of first exposure and second exposure effects with tetracycline (TC) on the freshwater cyanobacterium Microcystis aeruginosa and chlorophyceae Selenastrum capricornutum were investigated by determining a battery of parameters including algal biomass, chlorophyll fluorescence index Fv/Fm, superoxide dismutase (SOD) and malonaldehyde (MDA) in this study. In general, TC could significantly inhibit the growth and physiological progress including primary photochemistry and antioxidant system. However, upon the second exposure, the inhibitory effects of TC were decreased compared to the first exposure. And it suggests that Fv/Fm, SOD and MDA were more sensitive than algal biomass. In addition, M. aeruginosa showed stronger survivability than S. capriconutum.

► The first and second exposure of TC on Microcystis aeruginosa and Selenastrum capricornutum were studied.
► It can be concluded that TC had toxic effect on both M. aeruginosa and S. capricornutum.
► And the effects on biomass were lower at the second exposure.
► As for the effect on Fv/Fm, MDA and SOD, M. aeruginosa was more tolerent.