A tubeworm eats, or rather gets its energy and nutrition, from symbiotic microorganisms that live in a specialized spongy organ in its body. It supplies these microorganisms with carbon-based compounds absorbed from the ocean water that are not biological in origin. Instead, they come from vents in the seafloor.
Tube worms lack a mouth, gut or anus, since they do not eat per se. They use their tips, called plumes, which extend from the ends of their tubes, to absorb both the necessary compounds and oxygen for their symbiotes. The symbiotes live bound to specialized blood cells in an organ known as the trophosome. Once they settle down, tubeworms never move again from the spot at which they anchor, and some even grow root-like projections to keep themselves there. These roots are sometimes used to excrete chemical wastes into the surrounding sediment. Some species live near cold chemical vents in the seafloor, while others live near hot vents. The species near hot vents must tolerate a very wide range of temperatures, with differences of tens of degrees across the length of their bodies. Most of their bodies are protected by a tube made of chitin, a protein material, which can be either hard or leathery, depending on the species.