We like to think that life always finds a way to survive, and that the existence of species that can withstand terrible conditions is proof of this resilience. But once in a while, we have to face the fact that some environments are just too extreme for life to thrive.
One of these environments has been found in Antartica, a region called University Valley. It is extremely dry, exceptionally cold, and has a layer of permafrost (frozen soil) that has not changed for the last 150,000 years – conditions that resemble Mars, where we are hoping to one day find life. Researchers looked for the presence of bacteria in the soil, and came back empty-handed.
“Going into the study, we were sure that we would detect a functioning and viable microbial ecosystem in the permafrost soils of University Valley as we and others have done in Arctic and Antarctic permafrost, including in other sites at lower elevations in Antarctica,” Lyle Whyte, co-author of the study, said in a statement. “It is hard for both of us to believe that we may have reached a cold and arid threshold where even microbial life cannot actively exist.”
The site was chosen to test a NASA ASTEP (Astrobiology Science and Technology for Exploring Planets) project called IceBite, a drill designed to perforate the frozen soil of the Martian polar regions. University Valley is believed to resemble the conditions of Mars' northern polar region.
The team from McGill University analyzed the samples at the bottom of the boreholes. They looked for evidence of molecules produced by organic matter such as methane and carbon dioxide, traces of DNA, and they even tried to accelerate microbial growth. They did not find any indications that living organisms were present.
The research has implications for finding life on Mars. NASA
Jackie Goordial, the lead author of the research, said: “We don’t know if there is activity beyond our limits of detection. All we can say for sure is that after using all the current methods of testing available to us, the samples are unlike any other permafrost we have encountered to date on Earth.”
“If conditions are too cold and dry to support active microbial life on an analogous climate on Earth, then the colder, dryer conditions in the near-surface permafrost on Mars are unlikely to contain life,” added Whyte. “Additionally, if we cannot detect activity on Earth, in an environment which is teeming with microorganisms, it will be extremely unlikely and difficult to detect such activity on Mars.”
The results were published in The International Society for Microbial Ecology Journal.