A basin of biological gas
In the vast, intermontane Zaisan Basin of East Kazakhstan, a unique geological process is underway. The ground is releasing significant quantities of methane, the primary component of natural gas. This is however not ancient gas trapped for millions of years. Instead, it is being actively generated by immense underground communities of microorganisms. The basin's Cenozoic coal seams, relatively young geological formations, are a fuel source; they are the substrate for a living methane factory.
The process is known as microbial methanogenesis. Groundwater flowing through the porous coal seams introduces communities of microbes. A consortium of different bacteria and archaea works to break down the complex organic molecules of the coal. First, bacteria ferment the coal, producing simpler compounds like acetate, hydrogen (H₂), and carbon dioxide (CO₂). Then, a group of archaea called methanogens consumes these byproducts to produce methane. The dominant pathway in many coal beds is hydrogenotrophic methanogenesis, where archaea use hydrogen as an energy source and carbon dioxide as a carbon source, releasing methane as waste. This ongoing biological activity makes the Zaisan Basin a site of secondary biogenic gas formation.