The European Space Agency has detected signs of liquid water beneath the surface of Mars. It’s time to start thinking about whether life could be present in this newly discovered subterranean lake.
In 2003 the Mars Express Spacecraft was launched towards Mars and has been orbiting it ever since. Detection instruments aboard the spacecraft were focused onto an area of Mars known as the Southern Polar Layered Deposits, where large quantities of ice have previously been discovered. The researchers directed radio pulses at the surface and measured the time taken for them to return as well as their power. After some analysis, the researchers concluded that their readings were due to “water-saturated materials and/or layers of liquid water” (Science).
The discovery of this subterranean Martian lake gives rise to a staggering question: could life exist on Mars? This is definitely a possibility, but the conditions of the lake are not those in which life would typically thrive. Containing high concentrations of salts and with temperatures that could be as low as -68oC, this newly discovered lake isn’t exactly an ecological hotbed that astrobiologists can get horny about. Despite this, we shouldn’t rule out the possibility of life being present in the lake.
We know that liquid water has existed on the surface of Mars in the past, and it may have been habitable during this time. Life could have initially developed in these more favourable conditions, and then spread to the more extreme subterranean environments where it would have evolved to withstand the unfavourable conditions. In order to survive there, organisms would have to be able to withstand the high salinity and low temperatures.
On Earth, organisms are able to survive in high-salinity lakes via special proteins and other adaptations that resist the denaturing effect of salt. Organisms in extremely cold environments have developed antifreeze proteins to protect their DNA. It is possible that Martian microorganisms developed similar adaptations to deal with the conditions in this underground lake.
Future missions to Mars will look for signs of life, but it will be impossible to investigate the lake as it resides 1.5km below the surface and our current technology is not capable of getting us that deep. We should still remain hopeful though: Martian microorganisms may be discovered within the next few decades.