WASHINGTON -- Hoping to learn more about undersea volcanoes, scientists sent a camera-equipped submarine down to take a look. They got more than they bargained for, witnessing a deep-sea eruption.
"At first we really didn't understand what was going on," said Bob Embley, chief scientist on the April mission, which involved nearly three dozen researchers.
"We were seeing billowing clouds coming up and turning yellow. There was sulfur and rocks were flying out," said Embley, an oceanographer with the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory. "We realized we were the first to witness a deep-sea volcano during an eruptive episode."
He added: "The amazing thing is we were able to sample it. . . . It would not have been a good place to be in a manned submersible."
The material from the eruption is still being studied. It was highly caustic, Embley said, damaging the camera lenses even though the robotic submarine was quickly backed away from the volcano.
The volcano, with a rim 1,800 feet below the sea surface, was named "Brimstone Pit" by the scientists.
The discovery, northwest of the island of Rota in the Northern Mariana Islands, was made during a 21-day voyage to study undersea volcanoes in the western Pacific.
In upper levels of the oceans, life draws energy from sunlight. Because deeper areas are dark, life there gets energy from chemicals released by hot ocean vents.
At just over 600 feet deep, the researchers found a zone where the two overlap, finding both light-loving and chemical-using life forms, Embley said.
"The biologists were amazed to see this . . . two of earth's ecosystems overlapping. That is very unusual," he said. "We don't know the implications."
In another area of the Mariana Trench, the researchers found bubbles of liquid carbon dioxide being released into the sea, enlarging up to a thousand times and turning to gas as they drifted upward.
Steve Hammond, chief scientist for NOAA's Office of Ocean Exploration, termed the find "a natural laboratory where the effects of carbon dioxide on marine organisms can be studied."
The research was funded by the NOAA Ocean Exploration Program and the Natural Science and Engineering Research Council of Canada.