Cyanobacteria <span>/<span>saɪˌænoʊbækˈtɪəriə</span>/</span>, also known as Cyanophyta, are a phylum of bacteria that obtain their energy through photosynthesis,[4] and are the only photosynthetic prokaryotes able to produce oxygen.[5] The name "cyanobacteria" comes from the color of the bacteria (Greek: κυανός, <span>translit. </span>kyanós, <span>lit. </span>'blue').[6][7] 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.<span>[8]</span>
