Earth microbes survive simulated conditions of Saturn moon’s ocean

Key facts

• Earth microbes from deep-sea hydrothermal vents survived simulated conditions of Enceladus's ocean.
• The simulated ocean environment was highly alkaline, with a pH reaching 11.
• The microbes converted hydrogen and carbon dioxide into methane.
• Scientists recreated the ocean's alkaline environment and rock-water reactions in the lab.
• The European Space Agency's L4 mission aims to search for biosignatures on Enceladus.

Researchers have demonstrated that certain Earth microbes, specifically methanogens found near deep-sea hydrothermal vents, can survive in conditions mimicking the subsurface ocean of Saturn's moon Enceladus. These organisms thrive by converting hydrogen and carbon dioxide into methane. The experiments involved recreating the ocean's alkaline environment and the chemical reactions between water and rock on the seafloor. Despite the simulated ocean reaching a pH of 11, far more alkaline than the microbes' known limits, they not only survived but also adapted their metabolism. This finding strengthens the possibility that Enceladus could be habitable. Scientists also noted that ice grains in Enceladus's plumes might concentrate potential alien microbes, making them easier to detect with current technology. The European Space Agency has a proposed mission, L4, planned for launch around 2042, which aims to land on Enceladus and search for biosignatures.