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Deep SmokerCaptured by high-resolution cameras aboard a robotic submersible, mineral-rich water spews from hydrothermal vents in this June 30 picture of Kawio Barat, a massive undersea volcano off Indonesia.
During the past few weeks, the submerged volcano—one of the world's largest—was mapped and explored in detail for the first time by a joint Indonesian-U.S. expedition north of the island of Sulawesi (map).Mining companies first spotted the Kawio Barat volcano in the 1990s with satellite altimetry. But "we were the first to go there with a [remotely operated vehicle] and actually discover hydrothermal fluids coming out of the volcano," microbiologist Jim Holden, chief U.S. scientist for the Kawio Barat expedition, said in an email.(Watch video of the giant Kawio Barat underwater volcano.)—John Roach

Photograph courtesy INDEX/NOAA