Halobacteria

The halobacteria are a group of archaea, found in water saturated or nearly saturated with salt. They are also called halophiles, though this name is also used for other organisms which live in somewhat less concentrated salt water. They are common in most environments where large amounts of salt, moisture, and organic material are available. Large blooms appear reddish, from the pigment bacteriorhodopsin. This pigment is used to absorb light, which provides energy to create ATP. The process is unrelated to other forms of photosynthesis involving electron transport, however, and halobacteria are incapable of fixing carbon from carbon dioxide.