Microbiology
Microbiology (from Greek , "mīkros", "small"; , "bios", "life"; and , "-logia") is the study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, parasitology, mycology and bacteriology.
Geomicrobiology
Geomicrobiology is the scientific field at the intersection of geology and microbiology. It concerns the effect of microbes on geological and geochemical processes and vice versa. Such interactions occur in the geosphere (rocks, minerals, soils, and sediments), the atmosphere and the hydrosphere. Applications include aquifers and public drinking water supplies.