Cyanobacteria are an ancient and morphologically diverse group of photosynthetic prokaryotes. They were the first organisms to evolve oxygenic photosynthesis, and so changed the Earth's atmosphere from anoxic to oxic. Cyanobacteria contain photosynthesizing cells, nitrogen fixing heterocysts as well as spore-like cells called akinetes. The evolution of the akinete almost certainly preceded that of the heterocyst and, indeed, the akinete may have been the ancestor of the heterocyst. Akinetes are an impressive evolutionary characteristic that allow the cyanobacteria to survive when environmental conditions are not favorable for growth.
An akinete is a dormant non motile cell that has thick cell walls and acts as a survival system for the cyanobacteria. The akinetes are resistant to cold as well as to dessication and can accumulate nutrients and materials that are critical for the cyanobacteria’s survival. Akinetes give the cyanobacteria the opportunity to survive unfavorable conditions that other organisms may not be able to make it through. Lack of sunlight, phosphate deprivation or harmful saline levels are just a few of the conditions that the akinetes would be able to endure. These kinds of deteriorating circumstances would trigger vegetative cells to begin to transition into an akinete cell and basically help the cyanobacteria go into a form of survival hibernation. Once suitable conditions are reestablished, the akinete may transition back into a vegetative cell and the cyanobacteria can continue proliferating.