What organisms make up the bottom of the food chain at a hydrothermal vent?

At hydrothermal vents, the bottom of the food chain is primarily composed of chemosynthetic bacteria and archaea. These microorganisms utilize chemicals, such as hydrogen sulfide, emitted from the vents to produce energy through chemosynthesis. They serve as the primary producers, forming the basis of the food web, which supports diverse organisms like tube worms, clams, and various crustaceans that rely on these microbes for nutrition.