The study of how microorganisms affect the earth and its atmosphere is called environmental microbiology or microbial ecology.
Environmental microbiology is the study of microbes in the environment and their interactions with each other. Microbes are the tiniest creatures on earth, yet despite their small size, they have a huge impact on us and on our environment.
Environmental microbiology is the relationship of microorganisms with themselves and with their surroundings. Microorganisms have special impact on the whole biosphere. They are the backbone of ecosystems of the zones where light cannot approach. In such zones, chemosynthetic bacteria are present which provide energy and carbon to the other organisms there. Some microbes are decomposers which have ability to recycle the nutrients. So, microbes have a special role in biogeochemical cycles. Microbes, especially bacteria, are of great importance in the sense that their symbiotic relationship (either positive or negative) have special effects on the ecosystem.