Tiny worms can live in solid rock up to 3.6 kilometers underground, researchers have found, far deeper than anyone has encountered complex organisms before. The discovery of nematode worms in three South African gold mines underscores that Earth’s biosphere reaches well into subterranean realms. It also suggests habitable environments may exist buried way down on other planets, such as Mars.
Worm specialist Gaetan Borgonie and his colleagues present their findings, which include a new nematode species named after Faust’s devil Mephistopheles, in the June 2 Nature. Nematodes are an incredibly diverse group encompassing numerous intestinal parasites and the widely studied laboratory roundworm C. elegans.
Over the past few decades, researchers have found plenty of bacteria and other single-celled creatures thriving deep underground. But “to actually go out and start looking for multicellular organisms is such a game changer. Nobody in their right mind would think they were down there,” says team member Tullis Onstott, a geomicrobiologist at Princeton University.