What life exists below the surface of the earth?
Previously biologists believed the only subsurface life was at the soil zone, that you go a metre down and it is inconsequential, except for in caves. But even then the people looking in caves didn’t realise the caves were being formed by sub-surface life. There were actually bacteria eating the rocks that make the caverns. They were looking at these minerals and gypsum deposits and saying “how did these things get here, how did they form?” — not realising that these enormous rooms that exist in caves are produced by a thin layer of bacteria dissolving the rock in order to get minerals. That’s an underlying theme of all subsurface life. It’s bacteria eating rocks and living off energy in the rocks and in the process dissolving the rocks and making more room.