Saturn’s moon Enceladus has looked like a tantalizing possibility for life in the Solar System for quite some time. Now, we may have identified something that can live there and explain why we found methane in its plumes.
Published in Nature Communications, a study led by the University of Vienna describes a particular microbe found in the deep sea near Japan called Methanothermococcus okinawensis that could survive the temperature, pressure, and chemical make-up of the ocean hiding under the icy surface of Enceladus.
They say this microbe suggests that methane detected in the plumes of Enceladus by NASA's Cassini spacecraft could be produced by microbial life, specifically methanogens – those that produce methane. And a future mission may be able to spot the biosignatures from such organisms hiding in its possibly warm ocean.
“Some of the methane detected on Enceladus could in principle be of biological origin,” Dr Simon Rittman from the University of Vienna, the study’s corresponding author, told IFLScience.
“We are the first ones to investigate whether microorganisms could possibly produce methane under these conditions.”
In their study, the team investigated three microorganisms in the laboratory to see if they could survive conditions on Enceladus and produce methane. This includes pressure of up to 90 bars (sea level pressure on Earth is about 1 bar), and temperatures as low as 0°C (32°F) but as high as 100°C (212°F) – if hydrothermal vents exist on the sea floor, as predicted.
The team performed the experiment in flasks 20ml in size, with a liquid inside composed of inorganic compounds. They added the microbes to the mixture, along with hydrogen and carbon dioxide – providing both food and energy, as expected on Enceladus.