A new type of extremophile life has been discovered in Chile that may help us recognize what life on Mars may look like—and that will undoubtedly help in the search for discovering that life, should it exist.
Scientists pondering this very premise on exoplanets have long studied Earth-bound extremophiles for inspiration. These are living entities that eke out an existence in locations and under environmental situations that it's almost impossible to imagine—such as acidophiles that thrive in liquids with a pH of less than 3 (stomach acid is pH 1-3) or the hyperthermophiles that live in the vents and hotsprings in Yellowstone National Park. The existence of these bizarre life forms also suggests that life can exist in conditions found elsewhere in our solar system.
The conditions in the Atacama desert in Chile have been considered similar to the Martian surface environment for some years—it's the driest place on Earth, with some weather stations installed in the region never recording evidence of rainfall throughout their years-long lifespans.
Which makes the recent discovery of microbial communities atop the 20,000-foot Socompa volcano in the Atacama very interesting indeed. They apparently make the most of the gasses escaping from fumaroles to exist—the gasses themselves supplying many of the chemicals necessary to support life.
Meanwhile recent research has highlighted the region in and around Olympus Mons on Mars—the tallest volcano in the Solar System—as being one very likely location to look for life. Scientists at Rice University have been running geological and environmental simulations of the conditions on Mars, and have suggested that pockets of "ancient" water may be trapped in the rock layers under the mountain. They conclude that the water, minerals and warmth provided in such a location may be able to support life.
Given the findings in Chile, it's arguable that if bizarre extremophile life can thrive in very similar conditions on Earth in a hostile, dessicated environment near a volcano, then perhaps future life-hunting efforts on Mars may best be concentrated at Olympus Mons.