Ninety billion tons, nearly one-tenth of Earth's biomass, is made up of microbes living beneath the sea floor, according to two studies appearing this week in Proceedings of the National Academy of Sciences and Nature.

The Archaea group of organisms has just gotten a little bigger—and quite a bit deeper. Known to scientists as extremophiles—organisms which live in places inhospitable to other forms of life—the Archaea group is home to many single-celled creatures capable of thriving in environments of exceptional temperature, pressure, and acidity. The latest member has been discovered off the coast of Newfoundland, Canada, under 2.8 miles of water and a mile of rock. Previously, the deepest these organisms had been found underground was half as far.