Blue-green algae (Cyanophyta; lat. Cyanus - bluish, green) is a marine or freshwater unicellular eukaryotic plant from the group of algae, which has a bright blue-green glow, which determined the name for this group of algae.
They inhabit fresh and salt water bodies, deep-sea depressions, as well as ocean expanses (shallow water) at all depths of the World Ocean. Capable of growing in various environments: air, water, in the form of aqueous emulsions on the soil surface or on the leaves of aquatic plants.