RESISTANCE OF AN ALGAE BACTERIA PROTOZOA COMMUNITY TO THE ACTION OF CHLORATES

In experiments on continuous-flow mixed cultures of bacteria, green al gae, and infusoria, it was shown that, in the absence of unfavorable f actors, stable coexistence of algae and bacteria, and also of algae, b acteria, and protozoa is possible. With the addition of potassium chlo rate to the medium, the ''algae-bacteria'' community proved to be unst able, and algae were washed out of the culture; in the presence of inf usoria, the community acquired stability. A mathematical model is sugg ested, with the help of which the mechanisms of the ''algae-bacteria-p rotozoa'' community's resistance were revealed. They consist in creati on by protozoa of a cycle of the limiting biogen (nitrogen) and releas e of it into the medium in a form more acceptable for algae.