The impact of DON-1R on Microcystis sp. monocultures

The study is intended to investigate the impact of complex drug DON-1R on monocultures of Microcystis sp. Cyanobacteria of Microcystis aeruginosa (Kützing) Kützing та Microcystis pulverea (H.C.Wood) Forti are the dominant phytoplanton group in eutrophic freshwater bodies. They produce two main groups of toxin namely neurotoxins and peptide hepatotoxins. They were first characterized from the unicellular species, Microcystis aeruginosa, which is the most common toxic cyanobacterium in eutrophic freshwater. The waste water from recirculating aquaculture system (RAS), standardized on the indicators of pH and total mineralization, was used as a cultural medium for algae cultures of Microcystis aeruginosa and M. pulverea. The concentrations of DON-1R were elected, basing on preventive and therapeutic doses of the mentioned drug, recommended for use in fish farm ponds. It was found that the use of DON-1R leads to inhibition of growth activity in both investigated cultures. The morphological changes in algal cells (loss of a specific coloration, cells coagulation) under drug usage at all selected concentrations were revealed. It was noted that these changes are not related to exhaustion of culture media or pH fluctuations. The use of DON-1R results in the accelerated destruction rate of cyanobacteria cultures. At the final stages of cultivation the share of dead M. aeruginosa cells is about 90%, and M. pulverea – 100 %. The algicidal effect of complex drug DON-1R on algae cultures has been established on the changes of growth features and rapid destruction rate of M. aeruginosa and M. pulverea cultures. It was recommended to use the drug DON-1R in concentration of 16 µl / l to suppress the development of representatives from Microcystis genus.