Which process would bacteria living near a heat vent on the ocean floor use to build carbon-based molecules , such as sugars

Chemosynthesis is the process in which the bacteria living near a vent on the ocean floor use to build carbon based molecules, such as sugars. Down to the ocean floor, the sunlight can't be used as an energy to break down sugar instead it uses the heat in the ocean floor plus the sulfides floating in the water near the vent to produce carbon based molecules.