Hydrothermal

At the bottom of the ocean, there are small underwater volcanoes spewing scalding hot water, gases, and chemicals like methane and ammonia. They're called hydrothermal vents.

If you like astronomy, maybe read the paper "Ongoing hydrothermal activities within Enceladus."

The scientists say the existence of these large complex molecules, along with hydrothermal activity, supports a theory that a massive liquid water ocean, below the icy crust of Enceladus, may provide a habitable environment for life.