Scientists identify vast underground ecosystem containing billions of micro-organisms

The results suggest 70% of Earth’s bacteria and archaea exist in the subsurface, including barbed Altiarchaeales that live in sulphuric springs and Geogemma barossii, a single-celled organism found at 121C hydrothermal vents at the bottom of the sea.

One organism found 2.5km below the surface has been buried for millions of years and may not rely at all on energy from the sun. Instead, the methanogen has found a way to create methane in this low energy environment, which it may not use to reproduce or divide, but to replace or repair broken parts.

Lloyd said: “The strangest thing for me is that some organisms can exist for millennia. They are metabolically active but in stasis, with less energy than we thought possible of supporting life.”