geomicrobiology

Geomicrobiology is the study of interactions between microorganisms and geological materials, and of how microbial activity shapes geochemical and mineralogical processes. It sits at the intersection of microbiology, geology, and geochemistry, examining how microbes harvest energy from minerals, alter rock surfaces, and influence the cycling of elements such as carbon, sulfur, nitrogen, and metals.

Microorganisms inhabit a wide range of geologic settings, including soils, sediments, aquifers, rocks, permafrost, glaciers, and deep-sea hydrothermal systems. In these environments they mediate redox reactions, catalyze dissolution and precipitation of minerals, form biominerals, and contribute to weathering and ore formation. Subsurface communities live at high pressure, low energy, and often in energy-limited environments where they rely on minerals for energy.

Researchers use cultivation and culture-independent methods to study these communities, including metagenomics, metatranscriptomics, and metaproteomics, as well as microscopy, fluorescence in situ hybridization, and stable isotope probing. Advanced imaging and spectroscopy, nanoSIMS, and microelectrodes help link microbial identity to function and geochemical fluxes.

Geomicrobiology informs understanding of Earth's history and current biogeochemical cycles, aids in bioremediation and bioleaching, and has implications for the search for life on other planets by examining biosignatures preserved in minerals.

With roots in early microbiology and geology, geomicrobiology expanded in the late 20th century through discoveries of microbial life in subsurface and hydrothermal vent systems and the recognition of microbe–mineral interactions as major drivers of geochemical change.