mars
January 21, 2016

Lack of microbes in Antarctic permafrost dims hopes for life on Mars

The search for living microbes in the permafrost of Antarctica’s University Valley, a region that has been persistently cold and dry for more than 150,000 years, has thus far proven unsuccessful – and that could spell bad news for the search for life on Mars, according to a new study.

Jackie Goordial, a post-doctoral fellow in the McGill University Department of Natural Resource Sciences, analyzed more than 1,000 petri dishes worth of samples collected over a four-year span at University Valley, which is located in the high elevation of the McMurdo Dry Valleys.

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In University Valley, high in the McMurdo Dry Valleys of Antarctica, there is a layer of dry permafrost soil overlaying ice-rich permanently frozen ground. The ice in the permafrost of is formed not by liquid water, but by frozen water vapour; the absence of liquid water, makes the soil less likely to be able to sustain life. (Credit Jackie Goordial)

She and her fellow scientists hope to find signs of life in this region, as it is thought to be the one place on Earth most similar to the conditions found in the northern polar region of Mars, home to the Phoenix landing site. Thus far, however, they have been unable to find any such evidence.

In a statement, Lyle Whyte, Goordial’s supervisor and co-author of a new ISME Journal paper detailing the McGill team’s research, admitted that it was “hard for both of us to believe that we may have reached a cold and arid threshold where even microbial life cannot actively exist.”

“Going into the study, we were sure that we would detect a functioning and viable microbial ecosystem in the permafrost soils of University Valley,” he added. “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.”

Results make it ‘unlikely’ that activity can be found on the Red Planet

Goordial, Whyte and their colleagues initially travelled to University Valley as part of a NASA ASTEP (astrobiology science and technology for exploring planets) project that involved testing a new permafrost drill designed for use on Mars, the IceBite auger. Using the auger, they drilled 42 and 55 centimeter deep boreholes in the permafrost, then collected samples.

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Denis Lacelle of University of Ottawa (left) and Alfonso Davila of NASA/SETI (right) operate a motorized ice drill to obtain cores in ice-cemented ground in University Valley. (Credit NASA/Chris McKay)

Those samples were then run through a battery of tests both in the field and at laboratories back at the Quebec-based university. No evidence of carbon dioxide or methane, a gas used by every kind of living creature on Earth, were found in the soil. DNA testing found no matches to genes found in microbes or fungi, and other examinations similarly found no signs of active life.

“We couldn’t detect any microbial activity within these samples. Any, very limited traces we were able to find of microbial life in these samples are most likely the remnants of microbes that are dormant or are slowly dying off,” said Whyte. “Given the continuous dryness and subfreezing temperatures, and the lack of available water, even in summer, it is unlikely that any microbial communities can grow in these soils.”

“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,” he added. “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.”

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Feature Image: Mars. (Credit: NASA)