Organisms found in deep-sea waters off Japan have been shown to survive conditions expected in the ocean beneath Enceladus, one of Saturn's moons. This research suggests the distant world may be habitable for some forms of life.
The microbes, which typically thrive near hydrothermal vents by converting hydrogen and carbon dioxide into methane, survived in a brine that mimicked Enceladus's ocean. William Orsi, a professor of geomicrobiology at Ludwig-Maximilian University in Munich, stated that if similar organisms were on Enceladus, there is a good chance they could survive.
Observations from Nasa's Cassini probe and the James Webb space telescope have previously revealed water vapour plumes from Enceladus and evidence of a vast saltwater ocean under its icy crust. The seafloor is thought to contain hydrothermal vents, and organic substances were found in samples collected by Cassini last year.
The scientists recreated the extremely alkaline environment of Enceladus's ocean in a laboratory, including rock-water reactions that produce hydrogen. The microbes grew in this simulated ocean despite its pH reaching 11, which is more alkaline than their known limit, and adapted to low carbon dioxide concentrations. These findings are published in Science Advances.
David Rothery, a professor of planetary geosciences at the Open University, noted that demonstrating methanogenesis is possible in the simulated Enceladus ocean "removes another barrier to the viability of microbial life there." However, Orsi cautioned that the experiments lasted only days, and it is unknown if such microbes could survive for longer periods on the moon.