The scientists first observed the giant tube worms at Phoenix in December 1993. They also noticed a number of mineral deposits, some towering to heights of more than 30 feet. These structures form where hot vent water meets cold seawater, causing metal sulfides to precipitate out. The precipitating sulfides, which look like smoke, amass to form chimneys called black smokers. Like the vent fields, some smokers have names. Smoke and Mirrors, for example, has shelf-like overhangs that trap hot water rising from below, creating upside-down shimmering pools. The largest known black smoker is Godzilla, a 160-foot-tall structure off the coast of Oregon.
During a December 1993 dive to the Phoenix vent field, Alvin accidentally toppled a 33-foot-tall smoker. When the sub returned for a brief visit three months later, the chimney had already grown back 20 feet. Scientists were surprised by the speedy recovery, which seems to parallel the rapid growth of tube worms and other organisms at the vents. The visits to the Phoenix site give us a sense of how quickly these vents are colonized, says Van Dover.
Another expedition is planned for November. By then, the community of organisms now prospering at the vents may already be a ghost town. When the flow of hot, sulfide-rich water slows to a trickle , death also comes quickly.
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