Nitrosomonas and iron bacteria are the most common examples of chemoautotrophic bacteria because they are able to produce energy through a chemical process, according to Dr. John W. Kimball. These organisms are unique because they are able to produce the energy they need without photosynthesis.
Most organisms on the earth need photosynthesis to survive and to produce the energy they need to function. Chemoautotrophic organisms do not need these processes because they are able to oxidize the electron molecules that they take in from their own internal environments in order to survive. They do not live on anything other than molecules and are able to sustain themselves through the use of these electrons.
Chemoautotrophic bacteria are at the bottom of the food chain. They do not eat anything or take anything in other than at a molecular level and are essential to the survival of small sea creatures. Chemoautotrophic bacteria are responsible for methane, hydrogen gas and carbon monoxide that are found in the ocean. These gasses are a result of what happens when the chemoautotrophs convert the electrons to energy. Some chemoautotrophs, like the iron bacteria, are responsible for everyday things like the rust-colored stains that are often found on the inside of a toilet tank.