Scientists have observed bacteria that thrive at pressures 10,000 times greater than Earth’s atmospheric pressure.

A team working at the Geophysical Laboratory of Washington’s Carnegie Institution reported the findings in a recent issue of Science.

The researchers put a water sample containing the common intestinal bug E. coli and another type of bacteria called S. oneidensis in a device called a diamond anvil cell in which the pressure was raised to over 1 billion Pascals—equivalent to the force exerted 50 km below Earth’s crust.

These pressures are so high that at room temperature water solidifies into ice.

Although the extreme pressure killed most of the bugs in the experiments, a hardy minority managed to persist.

Those microbes were able to survive in small pockets where the water remained liquid and were still alive after the pressure was returned to normal.

Especially surprising is the survival of E. coli at these pressures, since one of its natural habitats is the relatively benign human intestine.

The finding raises hopes that life could exist in a potentially liquid ocean beneath the surface of Jupiter’s moon Europa, or deep in the Earth’s crust.