Viability of akinetes of the planktonic cyanobacterium Anabaena circinalis

The viability of akinetes of the planktonic isolate Anabaena circinalis was examined in controlled laboratory experiments. Akinetes are distinctly more resistant than vegetative cells to a variety of extreme physi­cal, chemical and biotic influences. They appear to be well protected against the effects of antimicrobial agents and are superior in tolerating longer exposures to most digestive enzymes tested. Akinetes of this cyanobacterium, however, are as susceptible as vegetative cells to certain exposures, like desiccation or ultraviolet radiation. The respiratory activity of akinetes is greatly effected by tem­perature as well as by exposure to light, and hence their viability is enhanced by storage at low temperature in the dark anaerobic lake sediments. The mass production of akinetes seems to be important for counterbalancing the many potential losses suffered through various environmental hazards.