Ecology and evolutionary biology听PhD student听Lara Vimercati examines a nieves penitentes structure on Volc谩n Llullaillaco in Chile. (Photos: Steve Schmidt/CU Boulder)
High in the Andes Mountains, dagger-shaped ice spires house thriving microbial communities, offering an oasis for life in one of Earth鈥檚 harshest environments as well as a possible analogue for life on other planets.
The distinctive icy blade formations known as nieves penitentes (or, 鈥減enitent ones鈥�) are named for their resemblance to praying monks in white robes and form in cold, dry conditions at elevations above 13,000 feet. The penitentes, which can range from a few inches to 15 feet high, 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.
And yet, as a听听led by CU听Boulder student researchers finds, these spires offer shelter for microbes by providing a water source in an otherwise arid, nutrient-poor environment.
In March 2016, CU Boulder students and faculty members traveled to Volc谩n Llullaillaco in Chile, the world鈥檚 second-highest volcano. The two-week expedition into the arid landscape, planned in collaboration with their Chilean colleagues, was no easy feat.
鈥淭his is a very remote area that鈥檚 difficult to access,鈥� said Steve Schmidt, a professor in CU Boulder鈥檚听Department of Ecology and Evolutionary Biology (EBIO)听and a co-author of the study. 鈥淭he entire back of one of our pickup trucks had to be filled with barrels of drinking water. It鈥檚 no trivial thing to go out there, and that鈥檚 one of the reasons these formations haven鈥檛 been studied much.鈥�
After reaching the penitente fields at 16,000 feet above sea level, the scientists noticed patches of red coloration, a telltale sign of microbial activity that has been previously observed in other snow and ice formations around the world.
Upon bringing back samples for analysis, the researchers confirmed the presence of algal species听颁丑濒补尘测诲辞尘辞苍补蝉听补苍诲听颁丑濒辞谤辞尘辞苍补蝉听in the ice, the first documentation of snow algae or any other life forms in the penitentes.
鈥淪now algae have been commonly found throughout the cryosphere on both ice and snow patches, but our finding demonstrated their presence for the first time at the extreme elevation of a hyper-arid site,鈥� said Lara Vimercati, lead author of the study and a doctoral researcher in EBIO. 鈥淚nterestingly, most of the snow algae found at this site are closely related to other known snow algae from alpine and polar environments.鈥�
The new findings add to scientists鈥� understanding of the limits of life on Earth, says Alexandra Krinsky, a co-author of the study and an undergraduate in the Department of Molecular, Cellular and Developmental Biology who helped analyze the samples.
"From looking at the extreme environments of the dry Andes to the aquatic life roaming the sea floor, we have broken the original ideas of where life can and has been found," she said.
The study听may also have implications for the search for alien life. Penitente-like formations have recently been discovered on Pluto and are speculated to exist on Europa, one of Jupiter鈥檚 moons. The Atacama region in Chile is also considered to be the best Earth analogue for the soils of Mars.
鈥淲e鈥檙e generally interested in the adaptations of organisms to extreme environments,鈥� Schmidt said. 鈥淭his could be a good place to look for upper limits of life.鈥�
鈥淥ur study shows how no matter how challenging the environmental conditions, life finds a way when there is availability of liquid water,鈥� Vimercati said.
Additional co-authors of the research include Adam Solon of CU Boulder; John Darcy of the University of Colorado Denver; Dorota Porazinska of the University of Florida; and Pablo Ar谩n and Cristina Dorador of the Universidad de Antofagasta (Chile). The work was supported by the National Science Foundation, the United States Air Force Office of Scientific Research and the National Geographic Society Committee for Research 补苍诲听Exploration.
