Microbes as geological agents
Many microbes are central geological agents that influence elemental cycles and hence recycle key nutrients and degrade organic as well as inorganic matter. "Microbial biogeochemistry is the study of microbially influenced geochemical reactions, enzymatically catalyzed or not, and their kinetics." 
Methods & applications
In biohydrometallurgy, microbes are used as geological agents by mining and water treatment industries in order to find new approaches and technologies to:
The types of microbes used in biohydrometallurgy to transform minerals are almost exclusively prokaryotes. The microbes used, in order to process and extract valuable metals from metal bearing materials (bioleaching microbes), are different from those that are used for remediating and treating metal containing solutions (Sulfate reducing bacteria).