Salty Martian Water Could Have Enough Oxygen to Support Life

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Salty water buried just beneath the Martian surface could have enough dissolved oxygen to support microbes, and perhaps even simple animal life such as sponges in some places, a new study suggests.

This surprising conclusion could help reshape scientists' understanding of the Red Planet's habitability, both past and present, study team members said.

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This surface water disappeared long ago, after Mars lost most of its atmosphere and transitioned to the cold, dry world that we know today. But researchers believe that some wet stuff probably persists underground to this day — in deeply buried aquifers as well as in salty brine pockets, some of which may lie just below the surface.

For example, some scientists think the seasonal Martian dark streaks known as recurring slope lineae are caused by the escape of such brines, which can remain liquid at much lower temperatures than "pure" water because of their salt content



The researchers found that Martian brines could hold a lot of oxygen — enough to support aerobic microbial life pretty much everywhere, if the requirements of these hypothetical Mars bugs mirror those of Earth. And the models showed that dissolved-oxygen capacity varies greatly both over time and from place to place, because it depends on temperature and, to a lesser extent, pressure. (The temporal variation is tied to shifts in Mars' obliquity — the tilt of its axis of rotation.)