Inner Earth Is Teeming With Exotic Forms of Life



More than a mile below the surface, our planet supports diverse creatures that could give us clues about life across the solar system


Nematodes (blue) wiggle inside a stalactite from a South African gold mine in this image taken with a microscope. (Gaetan Borgonie)

Ancient bacteria from nearly two miles below Earth’s surface: that’s what first drew Tullis Onstott to begin his search for life in the most unlikely of places. The geomicrobiologist had just attended a 1992 U.S. Department of Energy meeting about rocks estimated to be more than 200 million years old—older than most dinosaurs. These prehistoric rocks had been unearthed from a gas exploration well, and they turned out to be teeming with bacteria.

«That was pretty amazing to me. The idea that these bacteria had been living in these Triassic rocks since they were deposited at a time prior to the age of the dinosaurs, that idea caught my fancy,» says Princeton University’s Onstott.

⇐ cover image: Maggie Lau collects borehole water in a vial more than two miles below Earth’s surface in South Africa’s TauTona gold mine. (Francois Vermeulen (Geosciences Manager, AngloGold Ashanti Limited))