During the cold war, the U.S. Navy developed an elaborate underwater sound surveillance system to monitor the ocean for noisy Russian submarines. Since 1990, however, sosus has been available to civilian researchers listening for other things, such as whales and volcanic eruptions on midocean ridges. sosus detected its first eruption in 1993, and on February 18 it picked up another, 100 miles off the coast of Oregon along the Gorda Ridge. Like the first eruption, which occurred 200 miles to the northwest, this one emitted a huge plume of sub-seafloor minerals and strange microbes--heat-loving bacteria that many researchers believe may be among the most ancient organisms on Earth.
A month and a half after the first rumblings, a ship dispatched by the National Oceanic and Atmospheric Administration lab in Seattle visited the site, and researchers took samples of the mile-high, half-mile- thick plume. They also planted a float in it, which has enabled them to track its spread. These events inject exotic organisms into the ocean and give us a window into the biosphere below, says University of Hawaii geochemist Jim Cowen, who led the shipboard team. Being able to follow this injection of material and then revisit it gives us the best way to follow how the ocean is affected.