Acute Toxic Effects of the Cyanobacterium Microcystis aeruginosa on Daphnia magna

Various axenic strains of Microcystis aeruginosa were found to have different short term toxic effects on Daphnia magna. One of these toxic manifestations, the "blocking" effect, markedly reduced the food uptake by the daphnids. In addition, several of the Microcystis strains are lethal for juvenile and adult daphnids. No correlations were found between the blocking of ingestion, lethality to daphnids, and the "mouse-killing" factors of Mycrocystis. Thus, several toxic principles are responsible for the different short term toxic manifestations.