Cyanobacteria

Photosynthetic prokaryotes of the domain Bacteria, commonly called blue-green algae for the chlorophyll and phycobilin pigments that let them capture sunlight the way true algae do, despite being bacterial rather than eukaryotic cells. Covers free-living and colonial cyanobacterial species catalogued in this atlas, filamentous nitrogen fixers, planktonic and mat-forming genera alike, identified by their own sourced description rather than by name. Kept separate from the ordinary Bacteria subcategory because of this shared photosynthetic, historically algal classification, a distinction inherited from the older treatment of cyanobacteria as blue-green algae rather than from strict cladistics; excludes archaea and every non-photosynthetic bacterial lineage, which stay in Bacteria or, for archaea, in the separate Archaea subcategory.