“We found something very surprising: Many brines can exist in different places on Mars,” says Vlada Stamenkovic, a JPL scientist and lead author on the paper. “They fully suffice to allow the aerobic breathing for microbes and even sponges, which are the simplest animals.”
It also changes the view of Mars we’ve held since the 1960s, where the Mariner missions discovered a seemingly dry, desolate world. We’ve since looked for evidence of past water on Mars, which we have in abundance. That meant past life, and maybe an outside chance of extremely hardy present day microbes, a minority view.
But these findings mean that there may be a few places where life forms need not be so extreme—and that even after the surface of a planet becomes inhospitable, there may be more than meets the eye going on just below the surface.
“The last 40 years, people didn’t think oxygen would matter at all for life on Mars,” Stamenkovic says. “We wanted to change that dogma.”