Saturn's moon Enceladus could be more life-friendly than previously thought

According to a study, the planet Saturn's icy moon Enceladus could be even more life-friendly than previously thought. A team including researchers from the Ludwig Maximilian University of Munich (LMU), the University of Regensburg and the Free University of Berlin have demonstrated in laboratory experiments that certain microorganisms could survive in the moon's ocean hidden under ice.

It is already known that Saturn's moon is one of the places in our solar system whose conditions allow the emergence of life. “Enceladus is considered one of the most promising places for the search for extraterrestrial life,” said the first author of the study, Vanessa Helmbrecht, according to the LMU announcement. “Our experiments show that its unique geochemistry could create conditions that are even more favorable for microbial life than we previously thought.”

Researchers suspect that a global ocean of liquid water and a deeper rock core exist beneath the moon's icy crust. Using experiments, the researchers have now discovered that and how certain microorganisms could survive there.

The team recreated the conditions on the seafloor of Saturn's moon in the laboratory - and discovered that hydrogen-consuming and methane-producing ancient bacteria - so-called archaea - can cope with this inhospitable environment. Until now, such an environment was thought to be lethal for these anaerobic single-celled organisms.

For the study, which has now been published in the journal “Science Advances”, the experts built a special chamber to replicate the conditions on Enceladus. The oxygen concentration in it was extremely low - about 10,000 times lower than in the Earth's atmosphere. Under these conditions, they simulated both the moon's alkaline ocean and its rocky seafloor.

They then introduced Methanothermococcus okinawensis – an archaeon that lives in the deep sea on Earth. According to the information, this single-celled organism only needs the gases hydrogen (H2) and carbon dioxide (CO2) to generate energy. According to the information, this is one of the most original metabolic pathways that still occurs in living creatures on Earth today.

“The results were astonishing: the organism continued to grow in the Enceladus simulation and produced methane using hydrogen generated by water-rock reactions,” LMU said. One of the biggest challenges for potential life on Enceladus is the extremely low concentration of carbon dioxide caused by the high pH value of the ocean. The team was able to show that the archaeon was able to adapt and use the tiny amounts of available CO2 using its unique metabolism.

“Our study does not prove that there is life on Enceladus,” emphasized geobiologist William Orsi, corresponding author of the study. “But it shows that key geochemical features there could enable one of the oldest forms of metabolism of life.”

The search for life on Enceladus should continue: According to the information, the European Space Agency ESA recently announced that it wanted to take samples from the fountains that are thrown into space by geysers through the ice crust on its “L4” mission planned for 2042. Microbial life could then be searched for there.