PHOTO: EAST NEWS/PHANIE
Color enhanced scanning electron micrograph of cysts of the protozoan Hartmanella vermiformis on a laboratory-grown potable water biofilm. Aquatic bacteria were grown as biofilm on steel for one week. Hartmanella vermiformis protozoans were then added, and phagocytized the bacteria that multiplied within vesicles that became cysts in which the bacteria will live until they rupture.