Explained: Why finding the oldest water on Earth matters in the quest for life on Mars – The Indian Express

While NASAs Perseverance rover has been making news since reaching Mars in February, a 2016 study by Canadian geologists is also eliciting significant interest, for the clues it offers in the search for alien life, especially on the Red Planet.

The research, published in Nature Communications, is based on a discovery made by Dr Barbara Sherwood Lollar of the University of Toronto, who in 2009 extracted from a Canadian mine water that is 1.6 billion years old the oldest to be found on our planet.

The discovery of the water 2.4 km below the Earths surface has since been heralded as one of great importance, given its ramifications on what we know about the origin and evolution of our planet, the nature of water and life, as well as the possibility of finding life on Mars.

The worlds oldest water

Since 1992, Sherwood Lollar had been carrying out research at the Kidd Creek mine, located on the 2.7 billion-year-old Canadian Shield, one of the worlds largest continental shields meaning the oldest and least tectonically active parts of the Earths crust.

It was on an expedition in 2009 that a musty smell led Sherwood Lollar to make the crucial discovery. It literally is following your nose right up to the rock, to find the crack or the fractures where the water is discharging, she told the magazine Macleans. The water was highly saline ten times saltier than sea water.

According to the report, the researcher, who at the time was unaware of how old the water exactly was, sent a sample to UKs Oxford University, who informed her that it caused their mass spectrometer to break. Researchers then conducted studies for four years on the sample, finally settling at the 1.6 billion years figure.

What scientists found in the water

Investigations into the highly saline water led to a pathbreaking discovery: scientists found that chemolithotrophic microbes bacteria that can thrive in the most extreme surroundings had been able to survive in the subterranean liquid.

Researchers found that the microbes had been feeding on nitrogen and sulphate, and that the chemistry that supported them bore resemblance to ocean beds that are known to support similar such extreme life forms.

As it happens, the Canadian Shield, on which the Kidd mine is located, in the past used to form an ocean floor, as per the report. Over millions of years of flux, however, its horizontal seabed became vertical, now preserved in the mines rock walls from which the water sample was extracted.

Why this matters in the search for life on Mars

Being a continental shield, which suffers the least from plate tectonic activity, the Canadian Shield is the closest analogue on Earth to the subsurface of Mars, researchers believe.

Scientists argue that if life-supporting water can be found 2.4 km below the Earth, it may be possible that the same could be true in the case of the Red Planet. This hypothesis provides an impetus for missions like Perseverance, which are looking for signs of present or past life on Mars.

For her discovery, Sherwood Lollar was awarded the Gerhard Herzberg Canada Gold Medal for Science and Engineering worth 1 million Canadian dollars in 2019, as well as the John C Polanyi Award by the countrys Natural Sciences and Engineering Research Council in 2016, as per a Sciences Times report.

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Explained: Why finding the oldest water on Earth matters in the quest for life on Mars - The Indian Express