Cyanobacteria

Cyanobacteria (/saɪˌænoʊbækˈtɪəriə/), also known as blue-green bacteria, blue-green algae, and Cyanophyta, is a phylum of bacteria that obtain their energy through photosynthesis. The name "cyanobacteria" comes from the color of the bacteria (Greek: κυανός (kyanós) = blue).