British geochemist Professor John Parnell of Aberdeen University and Dr. Joseph Michalski, planetary geologist at the Natural History Museum, have found evidence that the subsurface of Mars could potentially have teemed with microbial life.
According to the British Scientists in a paper published in the Nature Geoscience journal, entitled, "Ground water activity on Mars and Implications for a deep biosphere," deposits formed from groundwater upwelling on Mars in the vast McLaughlin Crater could preserve critical evidence of subsurface microbial life.
According to the research authors, the McLaughlin Crater, one of the deepest craters on Mars, contains evidence of Magnesium-Iron bearing clays and carbonate minerals that formed in ground water-fed environment. Because water is considered essential for life, the evidence of groundwater in the McLaughlin Crater is critical indicator to scientists where to look for life on planet Mars.
NASA reports that crater "sits at the low end of a regional slope several hundreds of miles, or kilometers, long on the western side of the Arabia Terra region of Mars."
The McLaughlin crater was formed by a meteorite that crashed into the surface of Mars million of years ago, and flung rocks for miles. Results from analysis of the rocks in the vicinity of the McLaughlin crater, including data from NASA's Mars Reconnaissance Orbiter and ESA's Mars Express spacecrafts yielded evidence of clay and carbonate minerals formed through interaction with water. The scientists said that analysis shows that all conditions necessary for life were present just below the planet's surface for much of its history.
According to the research authors, discovery of minerals formed through interaction with water in rocks excavated by meteorite impact at the McLaughlin site provides "strongest evidence yet" that the subsurface of the planet may have supported simple micro-organisms in the past and that the Martian subsurface could still contain life.
The authors, in their study abstract, said:
"... the subsurface of Mars could potentially have contained a vast microbial biosphere. Crustal fluids may have welled up from the subsurface to alter and cement surface sediments, potentially preserving clues to subsurface habitability. Here we... evaluate evidence for groundwater upwelling in deep basins... McLaughlin Crater, one of the deepest craters on Mars, contains evidence for Mg–Fe-bearing clays and carbonates that probably formed in an alkaline, groundwater-fed lacustrine setting... Deposits formed as a result of groundwater upwelling on Mars, such as those in McLaughlin Crater, could preserve critical evidence of a deep biosphere on Mars."
According to The Telegraph, Professor Parnell, speaking from his laboratory at the University of Aberdeen, said: "We could be so close to discovering if there is, or was, life on Mars. We know from studies that a substantial proportion of all life on Earth is also in the subsurface and by studying the McLaughlin Crater we can see similar conditions beneath the surface of Mars thanks to observations on the rocks brought up by the meteorite strike. There can be no life on the surface of Mars because it is bathed in radiation and it's completely frozen. However, life in the subsurface would be protected from that. And there is no reason why there isn't bacteria or other microbes that were or still are living in the small cracks well below the surface of Mars."
The scientists said that their study suggests that the best place to look for life on Mars is around the edges of craters. Parnell said: "What we're really doing is emphasizing that if we are going to explore for life on Mars, we need to go beneath the surface. One approach to do that might be to drill and indeed the next European mission to Mars will have a drill on it, but that will only go down about two meters. And although drilling two meters would be a fantastic technological achievement, it's only really scratching the surface. So the alternative is to use what nature has done for us (i.e.the craters) and that's why we are particularly interested in the McLaughlin Crater that we have investigated in our paper."
Parnell believes that studying the Martian subsurface could yield valuable insights about how life began on Earth. He said: "It's very easy to draw parallels between what Mars looks like and what the early Earth might have looked like.. So studying meteorite craters of Mars may well actually give us an indication to how life on Earth began."
He added: "Although we all live on the surface of Earth, life did not originate here, but actually in the sub surface. In fact, there's so much life below the surface of our planet that we are actually the unusual ones living above it."
The authors are suggesting that with most of life on Earth consisting of micro-organisms living below the surface, the same could also be true of Mars.
The Daily Mail reports that Joseph Michalski, co-author of the paper, said: "All the ingredients were there for life, but only small single-cell organisms could have survived in those conditions. But I would now be more surprised if there was never any life on Mars, than I would be if we did one day discover that simple life lived in that environment. And if life existed then, there is a chance it could still exist now."
He added: "We don't know how life on Earth formed but it is conceivable that it originated underground, protected from harsh surface conditions that existed on early Earth. Exploring these rocks on Mars, where the ancient geologic record is better preserved than on Earth, would be like finding a stack of pages that have been ripped out of Earth's geological history book. Whether the Martian geologic record contains life or not, analysis of these types of rocks would certainly teach us a tremendous amount about early chemical processes in the solar system."