High in the Andes Mountains, dagger-shaped ice spires house blooming microbial communities, providing an oasis for life in one of Earth's harshest environments as well as a possible analog for life on other planets.
Known as nieves penitents, or "penitent one," the distinctive icy blade formations are named for their resemblance to praying monks in white robes and form in cold, dry conditions at elevations above 13,000 feet. Raging from a few inches to 15 feet high, the penitents are found in some of the most hostile conditions on Earth, with extreme winds, temperature fluctuations and high UV radiation exposure due to the thin atmosphere.
Even with that, a newly published study led by University of Colorado Boulder student researchers discovers that these spires provide shelter for microbes by providing a water source in an otherwise arid, nutrient-poor environment.
CU Boulder students and faculty members traveled to Volcan Llullaillaco in Chile, the world's second-highest volcano in March 2016. In collaboration with their Chilean colleagues, the two-week expedition into the arid landscape was no easy feat.
A professor in CU Boulder's Department of Ecology and Evolutionary Biology (EBIO) and a co-author of the study, Steve Schmidt, said that this is quite a remote area that is difficult to access. The entire back of one of their pickup trucks has to be filled with barrels of drinking water. Schmidt noted further that it's not a trivial thing to go out there and that is one of the reasons these formations have not been studied much.
When the scientist arrived at the penitente fields at 16,000 feet above sea level, they noticed patches of red coloration, a telltale sign of microbial activity that researchers have previously studied in other ice and snow formations all over the world.
After bringing back model for examination, the team established the presence of algal species Chlamydomonas and Chloromonas in the ice, the first documentation of snow algae or any other life forms in the penitentes.
The lead author of the study, Lara Vimercati, a doctoral researcher in EBIO, said that snow algae had been commonly found throughout the cryosphere on both ice and snow patches, but their finding demonstrated their presence for the first time at the extreme elevation of a hyper-arid site. Interestingly, most of the snow algae found at this site are closely related to other known snow algae from alpine and polar environments.
Scientists have added understanding of the limits of life on Earth with these new finding. However, they may also have implications for the search for alien life. Schmidt said that they are generally interested in the adaptations of organisms to extreme environments.
