Taxonomy term

Microbes live in some of the most extreme environments on Earth, from the crushing depths of deep-sea trenches to scalding geothermal springs. Part of the reason microbes thrive in many different environments is their ability to use a variety of energy sources — including light, organic matter, and inorganic materials like hydrogen, sulfur, and iron — to power the metabolic reactions that allow them to grow and survive.

In the early 1990s, when Hazel Barton was pursuing her doctorate in medical microbiology at the University of Colorado Health Sciences Center in Denver, she enjoyed exploring caves as a hobby. She never imagined that she would one day incorporate caving into her career.

Antarctica is nicknamed the “White Continent,” but one site — University Valley in the continent’s McMurdo Dry Valleys region — has remained virtually snow-free for more than 150,000 years, making it the coldest, driest desert on Earth. For the past four years, researchers involved in NASA’s ASTEP (Astrobiology Science and Technology for Exploring Planets) program searched for signs of life in the valley because it is thought to closely resemble the northern polar regions of Mars where the Phoenix spacecraft landed in 2008. In a new study, though, the team reports that it came up empty-handed, confirming that University Valley is indeed one of the least-habitable places on Earth.