Along cracks in the ocean floor plumes of black and white superheated water pump relentlessly into the depths. They provide precious heat to the near-freezing abyssal waters of the deep as well as a bounty of minerals.
Microscopic Archaea and other extremophiles live off the heat and minerals to form the base of a unique food chain that hosts a variety of exotic deep-sea creatures.
Control your hydrothermal ecosystem by adding new life and geological features each turn, competing to survive in the unforgiving depths by being efficient and preying on nearby systems with a host of strange and deadly predators.
Will your ecosystem survive?