Unusual Sea Volcano Spews Acid, Grows Fast

Deep-sea volcano that was initially observed erupting in 2004—a first—is continuously spewing lava and highly acidic molten sulfur (as seen in this April 2009 picture), the U.S. National Science Foundation announced on May 5.

An underwater "microphone" installed in 2008 near the Pacific volcano NW Rota-1 in the Northern Mariana Islands (map), near Guam, has consistently picked up sounds of volcanic activity, and an April 2009 expedition witnessed the explosions.

Between 2006 and 2009, the volcano also expanded 131 feet (40 meters) in height and 984 feet (300 meters) in width—about as tall as a 12-story building and as wide as a city block, said project chief investigator Bill Chadwick, an Oregon State University volcanologist. "It is unusual for a volcano to be continuously active, even on land," Chadwick said in a statement. "This presents us with a fantastic opportunity to learn about processes that we've never been able to directly observe before."



Two types of shrimp—including a new species—thrive in harsh chemical conditions on the NW Rota-1 volcano, which is toxic to other marine life, in April 2009.

The larger orange shrimp are of a new carnivorous species, which preys on the smaller shrimp species in the photo as well as on carcasses of creatures that had wandered too close to the noxious volcanic plume.

Scientists saw poisoned fish and squid "raining down" on the seamount, where they were immediately devoured by the predatory shrimp—"a lovely adaptation of exploiting the noxious effects of the volcano," Verena Tunnicliffe, a biologist from the University of Victoria in Canada, said in a statement.


A shrimp swarm gathers on the undersea volcano's summit in April 2009. Some of the crustaceans eat the fast-growing bacteria filaments that bloom around the hydrothermal vents.

These bacteria grazers, called Loihi shrimp, have previously been seen living only near a small, active underwater volcano in Hawaii.

At the Guam volcano, the shrimp have adapted tiny, garden-shear-like claws, which allow the animals to slice the filaments for easier consumption.



An arm of Jason (top right), a remotely operated vehicle (ROV), takes samples of NW Rota-1 during an April 2009 expedition.

The ROV can get close to the eruptive vent because water pressure at 1,700 feet (520 meters) suppresses some of the volcano's explosive energy, said project chief investigator Bill Chadwick, an Oregon State University volcanologist.

Some of the most "intriguing observations" during the expedition came from the volcano pushing lava up and out, Chadwick said in a statement. " … The ground in front of us shuddered and quaked, and huge blocks were bulldozed out of the way to make room for new lava."



The Jason ROV captures carbon dioxide bubbles by placing a funnel over the NW Rota-1 volcano in April 2009.

Volcanic plumes behave completely differently underwater than on land, where eruption clouds emit steam, ash, and invisible gases, said project chief investigator Bill Chadwick, an Oregon State University volcanologist.

In the ocean, steam condenses and disappears, leaving clear bubbles of carbon dioxide and a very acidic, dense cloud of molten sulfur, which is formed by sulfur dioxide mixing with seawater, Chadwick said in a statement.



In 2004 scientists found a new species of pink limpet snails (pictured), which at the time lived only in one small vent of the NW Rota-1 volcano.

Despite continuous eruptions, the snail has spread to many different sites on the volcano, scientists found in April 2009. The limpet reproduces by gluing its egg case to rock—the larvae later hatch and swim to a new site.

Other animals, including shrimp, crab, and barnacles, have also exploded in population since the volcano became more active—prompting experts to investigate whether there is a direct connection between volcanic eruptions and population explosions on NW Rota-1.