Tube worms reproduce by spawning: They release sperm and eggs, which combine in the water to create a new worm. Biologists dont know how the infant worm acquires its own bacteria. Perhaps the egg comes with a starter set.
Scientists also dont know how tube worms and other organisms locate new vents for colonization. The vents are small, and theyre separated, like island, says Cindy Lee Van Dover, a biologist and Alvin pilot who studies vent life. Most vent organisms have a free-swimming larval stage. But scientists arent sure whether the larvae float aimlessly or purposely follow clues-such as chemical traces in the water-to find new homes.
Studying the life cycle of vent organisms is difficult. Researchers have visited only a fraction of the oceans hot spots. They have been able to observe vent life only by shining bright lights on creatures accustomed to inky darkness, and many specimens die quickly when removed from their unique environment. Underwater cameras are helping scientists make less intrusive observations, but diving expeditions are still the most useful way to gather information. The1993 Alvin expedition to the East Pacific Rise was one in a series of dives to the area. The site was first visited in 1989, and scientists observed vent organisms thriving there. But when Alvin returned in April 1991, its flabbergasted occupants witnessed the birth of a hydrothermal vent. A recent volcanic eruption had spread glassy lava across the ocean floor, and the researchers measured temperatures up to 403C-the hottest ever recorded at a hydrothermal vent. The scientists dubbed the site Tube Worm Barbecue, because the worms they brought back to their ship had charred flesh.
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