Why Try To Find Life On Mars When You Could Just Put It There?

by Monica Joshi

The red planet. We've sent a rover to it. We've written science fiction novels about trying to conquer it and being attacked by preexisting life forms on it. We've even named aliens after it: martians. According to a study by a PhD candidate at University of Arkansas, it seems like there is a possibility that earth organisms could, in fact, survive on Mars.

Under simulated Martian conditions, methanogenic lifeforms have survived. In the quest for life on Mars, it has often been assumed that if simple life forms were to evolve, they would only need water and salts to survive. The discovery represents a small boost for the chances of life on Mars. Moreover, if the red planet turns out to be lacking life, it would be relatively easy for us to terraform it.

Rebecca Mickol, a PhD student at the University of Arkansas, pointed out at the American Society for Microbiology's annual conference that:

“The low surface pressure of Mars (7 mbar) is one condition that any extant life at the surface or near subsurface would need to endure.”

However, deeper within Mars, as pressures increase, the life at such depths may face other challenges. Mickol specifically wanted to examine whether it would be a problem for single cellular organisms to adapt to the conditions on Mars. As no other life on Earth has been faced with these challenges, it was going to be a hard feat.

This study builds on Mickol's previous demonstrations that two species can survive being repeatedly frozen and thawed in a manner likely to be experienced by Martian life.To study this possibility, Mickol chose four species that turn hydrogen and carbon dioxide into methane: Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum and Methanococcus maripaludis. The species are all members of the Archaea, which are neither bacteria nor eukaryotes and are known as methanogens.

According to Mickol,

“These organisms are ideal candidates for life on Mars. All methanogen species displayed survival after exposure to low pressure, indicated by methane production in both original and transfer cultures following each experiment.”

They were then tested for their ability to survive in water under pressures as low as 6 mbar. The chamber in which the organisms and their water solution were placed was given a thin atmosphere of 80% hydrogen and 20% carbon dioxide.

All four species survived the ordeal, demonstrating that low pressures are not an inherent obstacle to life on Mars. That this is true among species that have not had time to acclimatize is the most interesting part of the research.

One of the biggest concerns with this research is that we could be tampering with any chance we might have at finding new life on Mars. For example, when Curiosity detected methane last year, the possibility that it might have come from methanogenic species created great excitement. The organisms that we found could have snuck on board the Curiosity and flourished. There is a need to thoroughly sterilize whatever we send to Mars until we can be absolutely certain that no life on Mars actually exists. While the research shows a small possibility that we could send organisms to Mars, we should be wary of disturbing a system that we barely understand, before we even have a chance to understand it.