When we think of what it must be like far below the Earth’s surface, most of us picture the simplistic drawings we saw in grade school and believe there to be nothing there but deep layers of lifeless rock. Several recent studies on the subsurface biosphere illustrate just how wrong that line of thought is and how the various types of life found deep below have implications for someday finding native life on Mars.
One study was highlighted on Aeon.co Web site at https://aeon.co/essays/deep-beneath-the-earths-surface-life-is-weird-and-wonderful
The article states “We know now that the deep terrestrial subsurface is home to one quintillion simple (prokaryotic) cells. That is two to 20 times as many cells as live in all the open ocean. By some estimates, the deep biosphere could contain up to one third of Earth’s entire biomass.” The amount and diversity of life found deep below the Earth’s surface leads to some interesting speculation about what might be found under the Martian surface. It seems very possible that similar native species may have and (most interesting) might still survive deep under the surface of Mars.
One team of Russian scientists set out to see if some of the same species cited in the above mentioned study could survive under Mars atmosphere conditions. They found that a surprising number of species could survive under those conditions. If Earth species can survive in Mars atmosphere conditions, then it seems very likely that some native Martian species, which would have had a lot of time to evolve as the Martian atmosphere deteriorated, would have developed the ability to survive in those conditions.
Another interesting recent study showed that earthworms could survive and even breed in Martian soil. If Earthworms which have never had the need to evolve to conditions like Mars are able to survive in Martian soil, it is not hard to imagine that native Martian worms may very well have developed the same capability. They study covered in the Aeon.com article also mentioned the extensive existence of various types of Nematodes (commonly called roundworms, not to be confused with earthworms, which belong to a separate group, the Annelida) deep below the Earth’s surface. Nematodes have a proven track record for being able to survive in extreme environments. They are also one of the oldest multicellular organisms found on Earth. So it would not be surprising to find Martian nematode-like species living deep below the Martian surface.
These studies will become the basis for the science future generations use to hopefully find alien life on Mars, subsurface ocean moons like Europa and Enceladus and exoplanets we find in habitable zones around other stars. Already there are missions planned to begin studying the subsurface of Mars. The NASA Insight Mission is slated to launch in May of 2018 and reach Mars in late November 2018. Assuming a successful landing (Mars landers have failed on several previous missions), the Insight Mission lander will deploy a seismometer and drill a heat flow probe 5 meters below the surface near the Mars equator. These instruments will give us the first information we’ve ever had on what the interior of Mars.
In 2014, I wrote about using genetically modified Earth species to terraform Mars. It may turn out that it is not necessary to do so and that an established Mars Biosphere is already in place and just waiting for us to put in place an artificial Martian Magnetosphere to start Terraforming Mars for future human colonies.