Research published in Nature Communications has presented evidence that the world's oldest water, found deep below ground in Ontario, Canada, could host microbial life that has its own self-sustaining life-support system. These organisms, which are completely 'alien' to life on the surface, have greatly excited scientists.

"This continues to open up our idea of how much of this planet is habitable," Barbara Sherwood Lollar, a researcher from the University of Toronto, shared with The Globe and Mail. "And it speaks to the habitability of Mars as well."

The ancient water, discovered 2.4 kilometers deep inside a Northern Ontario mine in 2013, was estimated to have been closed off from the planet's surface for close to 2.64 billion years. This time span is estimated to be almost half the earth's history.

There is indirect evidence that the water contains unidentified life forms that are microbial in nature, surviving without oxygen or even sunlight deep beneath the earth's crust. Practically alien because of its long separation from the rest of the world's organisms, these microbes could be similar to the ones found in ancient water deep below the surface of South Africa.

Dr. Long Li, an assistant professor at the University of Alberta, collected samples of the ancient water from boreholes at the Kidd mine near Timmins, Ontario. Along with a team from McGill University, Dr. Li discovered that sulfur in the Kidd mine water is supplied by pyrite, a mineral present in the surrounding rocks. Radioactive in nature, the pyrite produced enough energy to dissolve the water's sulfur and turn it into sulfate. The chemical signature of the sulfate, according to Dr. Li, is evidence that this process seems to have started since the water was first isolated underground, leading to the creation of a long-term sustainable environment for bacteria.

"Because this is a fairly common geological setting in early Earth as well as modern Mars, we think that as long as the right minerals and water are present, likely kilometers below the surface, they can produce the necessary energy source to support the microbes," Dr. Li said in a feature in McGill University News and Events. "I'm not saying that these microbes definitively exist, but the conditions are right to support microbial life on Mars."