Method for the selective enumeration of blue-green bacteria in water.

A membrane filter method for the selective enumeration of blue-green bacteria has been developed which, on the basis of studies with laboratory cultures and field tests, has proved to be both practical and reproducible. The filters are incubated under specified conditions of temperature and illumination on a mineral salts agar medium supplemented with yeast extract and containing cycloheximide to eliminate eukaryotic contaminants.