Rock-Eating Organisms Thrive Beneath the Great Lakes

The water they pulled from gas wells drilled 650 to 1,640 feet (198 to 500 meters) below the Great Lakes hadn't touched the surface in over 11,000 years. What was living in it was not supposed to be there.

Researchers uncovered a thriving world of rock-eating fungi, worms and tardigrades buried hundreds of feet beneath the Great Lakes region. Their findings, published in The ISME Journal, identified 689 unique fungi species, including 13 newly described species, in drops of water that hadn't seen the surface world in thousands of years.

Here's what makes that genuinely strange: researchers have previously identified environmental DNA traces inside the planet, but frequently assumed the organisms living there were dormant or transient. The gas signature gave it away — carbon dioxide and methane in the samples pointed to organisms gnawing through the shale itself. Not resting. Eating rock.

Water drawn from gas wells drilled into the Antrim Shale, a formation spanning the entire Great Lakes basin, dates back to the Ice Age. Isotopic analysis indicates it likely hadn't seen the surface in over 11,000 years. When the ice sheets melted, that runoff seeped down through cracks and pores in the rock, ferrying bacteria and fungi with it. They went in, the door closed behind them, and they got on with it.

A single drop of the collected water contained roughly 250 fungal cells, the same density as a drop of ocean water. Scale that up to an Olympic-sized pool and you'd have approximately 12 trillion cells.

The lead researcher noted the team may be meaningfully underestimating the biomass and diversity of fungi on the planet, since subsurface habitats have never been factored into estimates of global fungal biodiversity. The planet's fungal census, it turns out, forgot to check downstairs.

The collection of more than 200 cultured fungi is now the first public collection of deep subsurface fungi, housed at the University of Michigan Herbarium. What 11,000 years in total darkness eating shale does to an organism's taxonomy is, presumably, a question someone is working on.

Read the full story at Popular Science, July 29, 2026

Hot Take: Cue Raising Arizona prison scene, "And when there was no organic matter, we ate rocks. You ate what? We ate rocks.