Fastest (growing) worms in the world.

In 1991, researchers in the undersea vessel Alvin came upon a barren patch of seafloor 2,500 meters down (top). Recent lava flows had destroyed almost all life along this 2.5 mile stretch of the East Pacific Rise, off southern Mexico. Yet a "snowstorm" of white bacteria had already blanketed the gray lava, recalls Richard A. Lutz, a biological oceanographer at Rutgers University in New Brunswick, N.J.

By 1993, the drifting larvae of giant tube worms had settled there -- along with fish and other organisms -- and grown 4 feet tall (bottom), Lutz and his colleagues report in the Oct. 20 NATURE and the November NATIONAL GEORGRAPHIC. "That's the fastest growth of any marine invertebrate that we have ever seen," Lutz says.

These organisms thrive near hydrothermal vents, where seawater seeps into crevices in Earth's crust, heats up, and resurfaces full of minerals and the sulfide compounds that fuel life there. As the water cools, it releases the minerals as a black "smoke" that forms a chimney around the emerging jet of water. The Alvin crew observed one chimney increase 20 feet in 3 months, an incredible pace.

"The rates both geologically and biologically are far faster than anyone had recognized," Lutz says.