There Must Be Something in the Water: Is there Life in Mars’s Lakes?

On the 25^th of July 2018, scientists announced an exciting discovery: promising signs were identified of a potential lake lying beneath layers of ice on Mars’s south pole. Researchers have long harboured suspicions that there might be water lurking on the planet, but the research led by Roberto Orosei of the Italian National Institute for Astrophysics is the first to point towards a proper body of water, and a large one at that—the lake is estimated to be around 12 miles in width.

The lake was spotted using low-frequency radio wave technology which can penetrate deep beneath the thick layers of ice. However, the low frequency also means that the results gleaned are not as precise, because the resolution of the reflected signal is relatively low. Because of this, the team’s conclusions are not yet certain, although they are confident that the existence of a lake is the most likely option presented by the data.

Could extraterrestrial life be swimming around in this polar lake?  It is certainly not a welcoming environment. Firstly, the temperature presents an obstacle to life. The lower limit for the majority of organisms on earth is around –40° Celsius; the ice layer on Mars is around –68° C. Secondly, for the water to exist in liquid form at such low temperatures is has to be very salty—another condition that poses a challenge to life. Similar conditions do exist on earth, for example in deep sea brine pools or in Antarctica’s subglacial lakes, and certain organisms (known as extremophiles) have adapted to life in or around these conditions. So although a Martian lake might kill off even the hardiest of such terrestrial species, it is not unthinkable that Martian organisms may be able to survive there. Finding out whether this is indeed the case would likely involve drilling below the ice, something which is not only beyond our current technological abilities but which would face opposition from the scientific communities. However, signs of methane variation in the planet’s atmosphere has been picked up as a possible sign that Mars’s liquid water may host life.

Applicants for physical and biological science degrees alike may be interested in the ongoing discussion about the potential Martian lake. How likely is it given the evidence that such a lake really exists? How likely is it that life can thrive and survive there?