The most common examples of autotrophic bacteria are cyanobacteria, which are photosynthetic organisms that use green and blue pigment. They are found in water sources such as lakes, ponds and oceans.
The second most common example is Prochlorococcus, a photosynthetic bacterium that lives in the sunlit surface waters of the oceans. This organism has been studied extensively because it has a very simple genome structure and produces a large amount of oxygen.
The third type is Synechococcus, another type of photosynthetic bacterium that lives in the open ocean and produces more energy than it needs to survive.