Geomicrobiology

Geomicrobiology is a subset of the scientific discipline microbiology. The field of geomicrobiology concerns the role of microbe and microbial processes in geological and geochemical processes. The field is especially important when dealing with microorganisms in aquifers and public drinking water supplies.

Another area of investigation in geomicrobiology is the study of extremophile organisms, the microorganisms that thrive in environments normally considered hostile. Such environments may include extremely hot (hot springs or mid-ocean ridge black smoker) environments, extremely saline environments, or even space environments such as Martian soil or comets.

Recent observations and research in hyper-saline lagoon environments in Brazil and Australia have shown that anaerobic sulfate-reducing bacteria may be directly involved in the formation of dolomite. This suggests the alteration and replacement of limestone sediments by dolomitization in ancient rocks was possibly aided by ancestors to these anaerobic bacteria.

Some bacteria use metal ions as their energy source. They convert (or chemically reduce) the dissolved metal ions from one electrical state to another. This reduction releases energy for the bacteria's use, and, as a side product, serves to concentrate the metals into what ultimately become ore deposits. Certain iron, uranium and even gold ores are thought to have formed as the result of microbe action.

Microbes are being studied and used to degrade organic and even nuclear waste pollution (see Deinococcus radiodurans) and assist in environmental cleanup. (It should be stressed however that microorganisms can not decrease the total radioactivity of nuclear waste.)

An application of geomicrobiology is bioleaching, the use of microbes to extract metals from mine waste.