extremophile

noun

1. Any of many organisms that live under extreme conditions of temperature, pressure, salinity, etc; many are autotrophs; some are commercially important as a source of enzymes that operate under similar conditions.

   “They had found the world's first extremophiles – organisms that could live in water that had previously been assumed to be much too hot or acid or choked with sulphur to bear life.”

   “Lichens are 'extremophiles', organisms able to live, from our point of view, in other worlds.”