Cyanobacteria / saɪˌænoʊbækˈtɪəriə /, also known as Cyanophyta, is a phylum of bacteria that obtain their energy through photosynthesis, and are the only photosynthetic prokaryotes able to produce oxygen. The name "cyanobacteria '' comes from the color of the bacteria (Greek: κυανός (kyanós) = blue). Cyanobacteria (which are prokaryotes) used to be called "blue - green algae ''. They have been renamed ' cyanobacteria ' in order to avoid the term "algae '', which in modern usage is restricted to eukaryotes.
where does blue green algae get their energy from
photosynthesis