Cyanobacteria

Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria of the phylum Cyanobacteriota that can obtain biological energy via oxygenic photosynthesis. Cyanobacteria apparently originated in a freshwater or terrestrial environment, and first appeared in the middle Archean eon. They are probably the most numerous taxon to have ever existed on Earth. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteria's informal common name, blue-green algae.

thumb|Fossilized stromatolite in Strelley Pool [[chert, about 3.4 billion years old, from Pilbara Craton, Western Australia]] thumb|Modern stromatolites in Shark Bay, Western Australia|Shark Bay, Western Australia

Dry biomass of cyanobacteria belonging to genus Limnospira, used as dietary supplement and food

thumb|300px|Lake Erie in October 2011, during an intense cyanobacteria bloom

thumbnail|Intercalary located akinete of Dolichospermum smithii thumbnail|Terminally located akinete of Gloeotrichia thumb|right|Akinetes, also termed "cysts", of Haematococcus An akinete is an enveloped, thick-walled, non-motile, dormant cell formed by both cyanobacteria and algae. Cyanobacterial akinetes are mainly formed by filamentous, heterocyst-forming members under the order Nostocales and Stigonematales. Eukaryotic microalgae also produce akinetes, such as Haematococcus.

Gloeobacter is a genus of cyanobacteria. It is the sister group to all other photosynthetic cyanobacteria. Gloeobacter's order, Gloeobacterales, is unique among cyanobacteria in not having thylakoids, which are characteristic for all other cyanobacteria and chloroplasts. Instead, the light-harvesting complexes (also called phycobilisomes), that consist of different proteins, sit on the inside of the plasma membrane (among the cytoplasm). Subsequently, the proton gradient in Gloeobacter is created across the plasma membrane, whereas it forms across the thylakoid membrane in cyanobacteria and ch

thumb|Nostoc with hormogonia Hormogonia are motile filaments of cells formed by some cyanobacteria in the order Nostocales and Stigonematales. They are formed during vegetative reproduction in unicellular, filamentous cyanobacteria, and some may contain heterocysts and akinetes.

Cyanophyceae is a class of cyanobacteria.

Scytonemin is a secondary metabolite and an extracellular matrix (sheath) pigment synthesized by many strains of cyanobacteria, including Nostoc, Scytonema, Calothrix, Lyngbya, Rivularia, Chlorogloeopsis, and Hyella. Scytonemin-synthesizing cyanobacteria often inhabit highly insolated terrestrial, freshwater and coastal environments such as deserts, semideserts, rocks, cliffs, marine intertidal flats, and hot springs.

thumb|Chroococcidiopsis thermalis can photosynthesize in far-red light, and might be suitable for future Mars colonists.

thumb|Modern thrombolites in Lake Clifton, Western Australia|400x400px thumb|Jurassic thrombolite formed around a tree trunk; Purbeck Formation, [[Isle of Portland, Dorset, England.|400x400px]] thumb|Fossil Thrombolites at Lake Walyungup|400x400px Thrombolites (from Ancient Greek θρόμβος thrómbos meaning "clot" and λῐ́θος líthos meaning "stone") are clotted accretionary structures formed in shallow water by the trapping, binding, and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.

REDIRECT Chroococcidiopsis

Microcystin-LR (MC-LR) is a toxin produced by cyanobacteria. It is the most toxic of the microcystins.

REDIRECT Cyanobacteria

thumb|Hot-springs with bacteria, [[cyanobacteria, and algae in Yellowstone National Park]] Thermophyte (Greek thérmos = warmth, heat + phyton = plant) is an organism which is tolerant or thriving at high temperatures. These organisms are categorized according to ecological valences at high temperatures, including biological extremes. Such organisms include hot-spring taxa also.

Group of photosynthetic plankton

Beltanelliformis is a cyanobacterial/putative algae genus of discoid fossil that lived during the Ediacaran period around 635 to 538.8 million years ago. It contains two species, B. brunsae and B. minutae. It is sometimes ascribed to the Ediacaran Biota. Depending on its preservation, it is sometimes referred to as Nemiana or Beltanelloides.

Cyanobionts are cyanobacteria that live in symbiosis with a wide range of organisms such as terrestrial or aquatic plants; as well as, algal and fungal species. They can reside within extracellular or intracellular structures of the host. In order for a cyanobacterium to successfully form a symbiotic relationship, it must be able to exchange signals with the host, overcome defense mounted by the host, be capable of hormogonia formation, chemotaxis, heterocyst formation, as well as possess adequate resilience to reside in host tissue which may present extreme conditions, such as low oxygen leve