*Ventworm cryocthonian*, the vent worm that brings cold from below.
1. Vent worm The fridge worm's body plan is familiar from terrestrial analogs — a tubular body with a protruding gill. The body hosts a colony of symbiotic bacteria in a chamber called the trophosome ("feeding body"). These bacteria help the worm survive extreme environments.
2. Cold water emitter The cryocthonian lives in colonies along geothermal gradients—from hot to cold. It exploits the flow of energy and minerals through the rock to feed. Colonies pumps deep, cold brine (usually at 4 degrees C) to the worms exposed to hot water, helping regulate their temperature.
3. Sulfur-based metabolism The symbiotic bacteria in the fridge worm feed on sulfur and other dissolved minerals. The fridge worm uses cold deep-sea brine to trigger chemical reactions which help collect minerals from the hot vent water.
Assessment: Produces pockets of cold water. May attract life that cannot tolerate the surrounding heat.