Mars Water: Too Salty for Life?

May 29, 2008 -- The debate about whether Mars once had water is pretty much over. The new quandary is if the water was suitable to support life.

As one group of scientists prepares for the first sampling of Mars' water with the Phoenix space probe, which landed on the Red Planet last Sunday, another team of researchers has nixed life's prospects there after studying salt deposits left behind on the planet's surface.

"If Martian life had to contend with the conditions we found, it certainly would have had a tough time," said Nicholas Tosca, a Harvard University geochemist and lead author of a paper on the research appearing in this week's Science.

Using data collected by the Mars rover Opportunity and other probes, Tosca and his colleagues determined that the planet's water would have been too salty for all but a handful of Earth's organisms to survive.

"If there is a window of life to survive on Mars, it's probably pushed back to when the planet was very young," Tosca told Discovery News.

As tough as survival would have been at Meridiani Planum, where Opportunity found evidence of an ancient shallow ocean, it would have been worse elsewhere, Tosca added.