‘Worms from hell’ unearth possibilities for extraterrestrial life

For the first time, scientists have found complex, multi-celled creatures living a mile and more below the planet’s surface, raising new possibilities about the spread of life on Earth and potential subsurface life on other planets and moons.

Nicknamed “worms from hell,” the nematodes, or roundworms, were found in several gold mines in South Africa, where researchers have also made breakthrough discoveries about deep subterranean single-cell life.

The two lead researchers, Gaetan Borgonie of the University of Ghent in Belgium and Tullis Onstott of Princeton University, said the discovery of creatures so far below ground, with nervous, digestive and reproductive systems, was akin to finding “Moby Dick in Lake Ontario.”

“This is telling us something brand new,” said Onstott, whose pioneering work in South Africa over the past decade has revolutionized the understanding of microbial life known generally as extremophiles, which live in places long believed to be uninhabitable.

“For a relatively complex creature like a nematode to penetrate that deep is simply remarkable,” he said.

An article introducing the subterranean nematodes, one of which was formally named Halicephalobus mephisto after the “Lord of the Underworld,” appears in Wednesday’s edition of the journal Nature. H. mephisto was found in water flowing from a borehole about one mile below the surface in the Beatrix gold mine.

The research is likely to trigger scientific challenges and cause some controversy because it places far more complex life in an environment where researchers have generally held it should not, or even cannot, exist.

Borgonie led the South African nematode investigation largely without professional support or funds. He contacted his future partner with a cold call. Onstott, who began his own deep mine work with similarly limited funds and amid similar professional skepticism, was both intrigued and inclined to help a fellow risk-taker.

Borgonie said that although nematodes are known to exist on the deep ocean floor, they have generally not been found more than 10 to 20 feet below the surface of the ground or the ocean bed. But he saw no reason they wouldn’t be found farther down. The nematodes he ultimately discovered live in extremely hot water coming from boreholes fed by rock fissures and pools.

In addition to uncovering a new realm of biology on Earth, Borgonie and Onstott wrote that this could have important implications for extraterrestrial research, or astrobiology.

Scientists seeking life beyond Earth are intrigued by the possibility that microbes could be living below the surface of Mars, in particular — a planet that is now cold, dry and bombarded by harmful radiation but was once much wetter, warmer and better-protected by an atmosphere.

“What we found shows that harsh conditions do not necessarily exclude complexity,” Borgonie said.

He said that if life did originate on Mars and if it had sufficient time to go underground deep enough to survive worsening conditions, “then evolution of Martian life might have continued underground. . . . Life on Mars could be more complex than we imagined.”