Nafanua, Eel City, and the Crater of Death.

In 1999, WHOI geochemist Stan Hart was co-chief scientist of a joint WHOI-Scripps Institution of Oceanography expedition that discovered and mapped Vailulu'u--an active volcano rising 4,360 meters (14,300 feet) from the Pacific Ocean seafloor. Resembling Mount Fuji, it sits atop a hot spot, fueled by magma erupting from the mantle, which will eventually build the volcano high enough to become the next island in the Samoan chain.

In April 2005, Hart and international colleagues returned to Vailulu'u to make more astonishing discoveries. They found a dome-shaped volcanic cone--growing inside Vailulu'u's milewide caldera--that didn't exist when the scientists last visited in 2001. This new volcano, named Nafanua after the ferocious Samoan goddess of war, stood 300 meters (1,000 feet) high.

Diving in the National Oceanic and Atmospheric Administration's manned submersible Pisces V, scientists explored the turbid waters surrounding Nafanua, where vigorous venting of hot, mineral-rich fluids creates a volcanic "fog." The area is covered with thick yellow mats of microbes that thrive on chemicals spewing from volcanic hydrothermal vents. Some areas were filled with large bubbles, fizzing like seltzer.

The scientists also found hundreds of greenish-white eels, ranging up to a foot long, emerging from rock caves and crevices and swarming around cavernous rock pillars. The scientists named this novel marine hydrothermal community "Eel City." In contrast, the scientists also found a possibly toxic zone, devoid of life, at the bottom of Vailulu'u's crater, which they dubbed the "Crater of Death."

The research was funded by the National Oceanic and Atmospheric Administration, the National Science Foundation, the Australian Research Council, and the WHOI Deep Ocean Exploration Institute.