As all the spheres, the biosphere and the atmosphere are in constant interaction with each other. The atmosphere is the sphere made out of gases, while the biosphere is the sphere made out of all the living organisms. The living organisms use the gases from the atmosphere for their functioning. As they use them, they either store them, release them as waste products, or change them. Once their usage is finished, the biosphere releases the majority of the gases back to the atmosphere, being also able to influence its composition on the long run. An excellent example of the interaction between the biosphere and the atmosphere, as well as the effect that it can have, is with the emerging of the cyanobacteria. The cyanobacteria used the carbon dioxide from the atmosphere for the process of photosynthesis. By using the carbon dioxide, the cyanobacteria has reduced the amount of this gas in the atmosphere. On the other hand, once used, the atom of oxygen from the carbon dioxide has been released into the atmosphere, gradually resulting in an increase in the oxygen levels in the atmosphere, making it the second most present gas in it. That resulted into enabling living conditions for other organisms to evolve and develop, and the circle has been continuing ever since.
