Life finds a way. It seems wherever we look, microbes are there, whether high in the sky or more than a kilometer deep underground.

And now scientists have found signs of life more than 11 kilometers beneath the ocean's surface. Even at that crushing, frigid depth, there’s eating going on. That’s what a study in the journal Nature Geoscience finds.

A deep-sea lander with oxygen sensors found signs of microbial metabolism at the Challenger Deep, the oceans’ deepest spot. A video camera also saw shrimp-like creatures called amphipods busy scavenging. And sediment samples brought carefully to the surface were found to contain bacteria and archaea.

The scientists suggest that life this deep is possible because the region is a nutrient trap—the researchers found that the sediment at Challenger Deep is richer in food supplies than sediment at more shallow depths nearby.

The research also shows that James Cameron was flat out wrong during his pioneering dive to this dark depth last year. He opined that he was looking out on a "sterile, almost desert-like place" but hardly anything on Earth is sterile, including deserts. That may hold true for Mars as well. Whatever the conditions, don't bet against the microbes.

—David Biello

[The above text is a transcript of this podcast.]