Cold salty water on Mars may have enough oxygen for air breathing microbes, possibly even simple animals like sponges

Tuesday, October 23, 2018

In a study published on 22nd October in Nature Geosciences, scientists reported that, despite previous suppositions, the trace amounts of oxygen in the thin atmosphere of Mars may get concentrated into salty seeps of water on its surface at levels enough to support marine life … just not human or animal life, the air is far too thin for that. Marine life on Mars however, especially simple sponges, may be able to survive there.

According to their simulations, the concentration of oxygen can vary from around 2.5 millionths of a mole per cubic meter to as high as two moles per cubic meter (a mole of oxygen is a little under 32 grams). Deep sea water has a concentration of around 0.1 moles per cubic meter. The authors cite research from 2014 that showed that some simple sponges can survive with only 0.002 moles per cubic meter . Some microbes that need oxygen can survive with as little as a millionth of a mole per cubic meter. There a mole of oxygen is just short of 32 grams .

The highest concentrations would be reached at lower altitudes, where the air is denser. The lowest points such as the Hellas basin, a huge impact crater south of the equator, have pressures around 1% of Earth atmosphere. Much of the northern hemisphere of Mars is the bed of an ancient ocean and is lower in altitude than the more mountaineous southern hemisphere.

The highest oxygen concentrations also occur when the water is colder, and so would be most easily attained in polar regions.

Their research helps to explain the presence of some highly oxygenated minerals on the Mars surface, for instance the blueberries. These are blue spheres that Opportunity discovered litters the landscape in some parts of Mars. These are familiar from some analogue landscapeson Earth[blueberries cite]. Although on Earth life is involved in their formation[blueberries need life cite], on Mars they may be formed inorganically, but would need water with high levels of oxygen in it.

[To do – summarize the research itself, how they came to the conclusion that oxygen rich water is possible on Mars, and how the oxygen gets into the water, and whether it is dependent on the water being salty, and if so, why]

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