If life exists in deep subsurface oceans on icy moons, what energy source replaces stellar radiation?

Answer

Chemical energy derived from hydrothermal vents.

Life in deep, dark subsurface oceans is hypothesized to rely on chemical energy, similar to Earth's deep-sea ecosystems, which are fueled by processes occurring at hydrothermal vents on the seafloor.

If life exists in deep subsurface oceans on icy moons, what energy source replaces stellar radiation?
supportsystemstarplanetlife