These worms were found in 1977 when the submersible Alvin was exploring the ocean floor of the Galapagos Ridge (located 1.5 miles [2.4 kilometers] below the Pacific Ocean surface and 200 miles [322 kilometers] from the Galapagos Islands). Riftia pachyptila Jones, named after worm expert Meredith Jones of the Smithsonian Museum of Natural History, were discovered near the hydrothermal (hot water) ocean vents. Growing to lengths of five feet (1.5 meters), the worms lack both mouth and gut, and are topped with feathery plumes composed of over 200,000 tiny tentacles. The phenomenal growth of these worms is due to their internal food source-symbiotic bacteria, over 100 billion per ounce of tissue-that live within the worms' troposome tissues. To these troposome tissues, the tube worms transport absorbed oxygen from the water, together with carbon dioxide and hydrogen sulfide. Utilizing this supply, the bacteria living there in turn produce carbohydrates and proteins that the worms need to thrive.
This was only one of Alvin's discoveries during its historic voyage. Scientists expected to find a "desert" at these ocean depths where no light penetrated. Most of the world's organisms rely on photosynthesis (the use of light to make organic compounds) at the base of their food chains. But in these depths, giant tube worms, vent crabs, and mollusks thrive because these vent communities depend on chemoautotropic (chemically self-feeding) bacteria, which derive their life-sustaining energy from the oxidation of substances spewing from the vents, or in symbiotic relationships, such as that with the giant tube worms.
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