Laboratory Studies on the Toxins Produced by Waterblooms of Blue-Green Algae

Abstract

Fifty-two strains representing 11 species of planktonic blue-green algae were isolated, grown in unialgal culture and tested for toxicity to mice and other animals. Toxic and non-toxic strains of Microcystis aeruginosa and Anabaena flos-aquae were discovered. Toxic strains of Microcystis produce a fast-death factor that is a moderately potent polypeptide composed of seven different amino acids. Toxic strains of An. flos-aquae produce a very-fast-death factor whose structure has not yet been identified. Strains of Aphanizomenon flos-aquae and of the other eight species tested are all non-toxic. Certain species of bacteria that are commonly associated with these algae produce slow-death factors of unknown structure. Waterblooms vary in toxicity because of differences in dominant strains of algae and bacteria, in toxin production and accumulation, and in animal susceptibility.