blue-green alga

English

blue-green alga (plural blue-green algae)

Any member of the taxonomic class or phylum Cyanobacteria; a primitive photosynthetic organism similar to bacteria which is thought to have generated the first oxygen in the Earth's atmosphere.
- 1967, George K. Reid, edited by Herbert S. Zim and George S. Fichter, Pond Life, New York: Golden Press, →LCCN, →OCLC, page 31:
  Blue-green algae cells lack nuclei, and pigment is scattered.
- 2023 August 23, Tommy Greene, “Lough Neagh ‘dying in plain sight’ due to vast algal blooms”, in The Guardian‎^[1], →ISSN:
  Northern Ireland’s Lough Neagh, the largest lake in the British Isles, has been hit by recorded levels of potentially toxic blue-green algae that regional agencies say have not been seen since the 1970s.

The term alga is now considered improper scientific usage, since true algae are eukaryotic organisms, rather than bacteria. It remains in common use among aquarists and others, however.

member of cyanobacteria