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Cyanobacteria often live in colonial aggregates that can take a multitude of forms. [3] Of particular interest among the many species of cyanobacteria are those that live colonially in elongate hair-like structures, known as trichomes. These filamentous species can contain hundreds to thousands of cells. [3]
Cyanobacteria remained the principal primary producers throughout the latter half of the Archean eon and most of the Proterozoic eon, in part because the redox structure of the oceans favored photoautotrophs capable of nitrogen fixation. However, their population is argued to have varied considerably across this eon.
[2] [4] [5] Formation of an anaerobic envelope to prevent nitrogenase from being irreversibly damaged in the presence of oxygen is an important strategy employed by nitrogen-fixing cyanobacteria to carry out fixation of di-nitrogen in the air, via nitrogenase, into organic nitrogen that can be used by the host. [6]
[79] [80] The release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Because oxygen was toxic to most life on Earth at the time, this led to the near-extinction of oxygen-intolerant organisms, a dramatic change which redirected the evolution of the major animal and plant ...
The heterocysts' unique structure and physiology require a global change in gene expression. For example, heterocysts: produce three additional cell walls, including one of glycolipid that forms a hydrophobic barrier to oxygen; produce nitrogenase and other proteins involved in nitrogen fixation; degrade photosystem II, which produces oxygen
Polyhedral bodies were discovered by transmission electron microscopy in the cyanobacterium Phormidium uncinatum in 1956. [11] These were later observed in other cyanobacteria [12] and in some chemotrophic bacteria that fix carbon dioxide—many of them are sulfur oxidizers or nitrogen fixers (for example, Halothiobacillus, Acidithiobacillus, Nitrobacter and Nitrococcus; all belonging to ...
[20] [21] The release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Because oxygen was toxic to most life on Earth at the time, this led to the near-extinction of oxygen-intolerant organisms, a dramatic change which redirected the evolution of the major animal and plant ...
[40] [41] This is an important step in atmospheric carbon sequestration, commonly referred to as the biological pump, and maintenance of other biogeochemical cycles. [40] Cyanobacteria perform oxygenic photosynthesis which is thought to be the origin of atmospheric oxygen approximately 2.5Ga ago. [42]