Mars likely to have enough oxygen for life: Study

PARIS: Salty water just below the surface of Mars could hold enough oxygen to support the kind of microbial life that emerged and flourished on Earth billions of years ago, researchers reported on Monday.

In some locations, the amount of oxygen available could even keep alive a primitive, multicellular animal such as a sponge, they reported in the journal Nature Geosciences.

“We discovered that brines” – water with high concentrations of salt – “on Mars can contain enough oxygen for microbes to breathe,” said lead author Vlada Stamenkovic, a theoretical physicist at the Jet Propulsion Laboratory in California.

“This fully revolutionises our understanding of the potential for life on Mars, today and in the past,” he said.

Up to now, it had been assumed that the trace amounts of oxygen on Mars were insufficient to sustain even microbial life.

“We never thought that oxygen could play a role for life on Mars due to its rarity in the atmosphere, about 0.14%,” Stamenkovic said.

By comparison, the life-giving gas makes up 21% of the air we breathe.

On Earth, aerobic – that is, oxygen breathing – life forms evolved together with photosynthesis, which converts CO2 into O2.

The gas played a critical role in the emergence of complex life, notable after the so-called Great Oxygenation Event some 2.35 billion years ago.

But our planet also harbours microbes – at the bottom of the ocean, in boiling hotsprings – that subsist in environments deprived of oxygen.

“That’s why – whenever we thought of life on Mars – we studied the potential for anaerobic life,” Stamenkovic said.

The new study began with the discovery by Nasa’s Curiosity Mars rover of manganese oxides, which are chemical compounds that can only be produced with a lot of oxygen.

Curiosity, along with Mars orbiters, also established the presence of brine deposits, with notable variations in the elements they contained.

A high salt content allows for water to remain liquid – a necessary condition for oxygen to be dissolved – at much lower temperatures, making brines a happy place for microbes. – AFP