<P> They have a highly vascularized , red `` plume '' at the tip of their free end which is an organ for exchanging compounds with the environment ( e.g. , H S , CO , O , etc . ) . The tube worm does not have many predators . If threatened , the plume may be retracted into the worm 's protective tube . The plume provides essential nutrients to bacteria living inside the trophosome . Tube worms have no digestive tract , but the bacteria ( which may make up half of a worm 's body weight ) convert oxygen , hydrogen sulfide , carbon dioxide , etc. into organic molecules on which their host worms feed . This process , known as chemosynthesis , was recognized within the trophosome by Colleen Cavanaugh . </P>
<P> They have a highly vascularized , red `` plume '' at the tip of their free end which is an organ for exchanging compounds with the environment ( e.g. , H S , CO , O , etc . ) . The tube worm does not have many predators . If threatened , the plume may be retracted into the worm 's protective tube . The plume provides essential nutrients to bacteria living inside the trophosome . Tube worms have no digestive tract , but the bacteria ( which may make up half of a worm 's body weight ) convert oxygen , hydrogen sulfide , carbon dioxide , etc. into organic molecules on which their host worms feed . This process , known as chemosynthesis , was recognized within the trophosome by Colleen Cavanaugh . </P>
how do chemoautotrophic bacteria and archaea that live near hydrothermic vents obtain energy
how do chemoautotrophic bacteria and archaea that live near hydrothermic vents obtain energy
a highly vascularized , red `` plume '' at the tip of their free end
a highly vascularized , red `` plume '' at the tip of their free end