Ecology of Blue-Green Algal Viruses

Blue-green algal viruses have wide geographical distributions and are present in both fresh water and marine environments. Population control of Plectonema boryanum, a ubiquitous nonblooming alga, may result from infection and lysis of the cells by LPP viruses. The maintenance of the virus in the environment may be the result of lysogenized host cells with occurrence of both spontaneous and stress induction. This has been demonstrated in laboratory culture. A protozoan is described that serves as a probable reservoir for the cyanophage. Since the host algae are extremely difficult to isolate in the presence of the virus, this protozoan may be the dispersal agent along with the state of lysogeny.