Unique and new species thriving around erupting undersea volcano

04/06/2009 09:42:42 Scientists return to erupting undersea volcano; find massive cone, new species
June 2009. Scientists who have just returned from studying an erupting undersea volcano near the Island of Guam report that the volcano appears to be continuously active, has grown considerably in size during the past three years and its activity supports a unique biological community that is thriving despite the eruptions.

An international science team on the expedition, which was funded by the National Science Foundation, captured dramatic new video of the eruptive activity of NW Rota-1, which remains the only place on Earth where a deep submarine volcano has ever been directly observed while erupting.

New 40 metre high cone
Scientists first observed eruptions here in 2004 and again in 2006, said Bill Chadwick, an Oregon State University volcanologist and chief investigator on the expedition. This time, however, they discovered that the volcano had built a new cone that is 40 metres high and 300 metres wide since they had last visited.

"That's as tall as a 12-story building and as wide as a full city block," Chadwick said. "And as the cone has grown, we've seen a significant increase in the population of animals that live atop the volcano. We're trying to determine if there is a direct connection between the increase in the volcanic activity and the population increase.
New species and specially adapted species

"The animals in this unusual ecosystem include shrimp, crab, limpets and barnacles, some of which are new species," Chadwick added. "They are specially adapted to their environment and are thriving in harsh chemical conditions that would be toxic to normal marine life.

"Life here," he said, "is actually nourished by the erupting volcano."

Verena Tunnicliffe, a biologist from the University of Victoria, said most of the animals the scientists observed were dependent on diffuse hydrothermal venting that provides basic food in the form of bacterial filaments coating the rocks.

Volcanic shrimps
"It appears that since 2006 the diffuse venting has spread and, with it, the vent animals," Tunnicliffe said. "There is now a very large biomass of shrimp on the volcano and two species are able to cope with the volcano conditions. The ‘Loihi' shrimp has adapted to grazing the bacterial filaments with tiny claws like garden shears. The second shrimp is a new species - they also graze as juveniles, but as they grow to adult stage their front claws enlarge and they become predators."

The shrimp reveal intriguing adaptations to volcano living, according to Tunnicliffe. The Loihi shrimp was previously known from only a small active volcano near Hawaii - a long distance away. It survives on the fast-growing bacteria and tries to avoid the hazards of the volcanic eruptions. Clouds of these shrimp were seen apparently fleeing volcanic bursts.

The other species attacks the Loihi shrimp and preys on marine life that wanders too close to the volcanic plumes and dies. "We saw dying fish, squid, etc., raining down onto the seamount, where they were jumped on by the volcano shrimp - a lovely adaptation of exploiting the noxious effects of the volcano," Tunnicliffe said.

The new studies are important because NW Rota-1 provides a one-of-a-kind natural laboratory for the investigation of undersea volcanic activity and its relation to chemical-based ecosystems at hydrothermal vents where life on Earth may have originated.

Degassing lava erupts onto the seafloor at NW Rota-1 volcano, creating a billowing cloudy plume that is extremely acidic, and is full of carbon dioxide and sulfur. (photo credit: copyright Woods Hole Oceanographic Institution)

Deep ocean volcano
"It is unusual for a volcano to be continuously active, even on land," Chadwick pointed out. "This presents us with a fantastic opportunity to learn about processes that we've never been able to directly observe before," he said.

"When volcanoes erupt in shallow water they can be extremely hazardous, creating huge explosions and even tsunamis. But here, we can safely observe an eruption in the deep ocean and learn valuable lessons about how lot lava and seawater interact."

Chadwick said that volcanic plumes behave completely differently underwater than on land, where the eruption cloud is filled with steam and ash, and other gases are invisible.

Highly acidic sea water
"In the ocean, any steam immediately condenses and disappears and what is visible are clear bubbles of carbon dioxide and a dense cloud made of tiny droplets of molten sulphur, formed when sulphur dioxide mixes with seawater," Chadwick said. "Both of these volcanic gases make the eruption cloud extremely acidic - worse than stomach acid - which is another challenge for biological communities living nearby."

Ocean acidification is a serious concern because of human-induced carbon dioxide accumulating in the atmosphere. "Submarine volcanoes are places where we can study how animals have adapted to very acidic conditions," Chadwick said.

During the April 2009 expedition, which was aboard the University of Washington's R/V Thompson, the scientists made dives with Jason, a remotely operated vehicle (ROV) operated by Woods Hole Oceanographic Institution.

"It was amazing how close the Jason can get to the eruptive vent because the pressure at a depth of 520 metres (or about 1,700 feet) in the ocean keeps the energy released from the volcano from becoming too explosive," Chadwick said. "Some of the most intriguing observations for the scientists came when the volcano would slowly push lava up and out of the erupting vent.

"As this was happening, the ground in front of us shuddered and quaked, and huge blocks were bulldozed out of the way to make room for new lava emerging from the vent," he added.

Constant eruption
Part of the evidence that the volcano is in a constant state of eruption comes from an underwater microphone - or hydrophone - that was deployed a year ago at NW Rota-1 by Oregon State University geologist Bob Dziak. The hydrophone "listened" for the sounds of volcanic activity and the data it recorded clearly shows the volcano was active the entire year before the latest expedition. Another hydrophone and other instruments will monitor the volcano for the coming year.

The international team included scientists from OSU, University of Washington, University of Victoria, University of Oregon, NOAA's Pacific Marine Environmental Laboratory, New Zealand and Japan.

More information, including science blogs, video and photographs, is available at: http://nwrota2009.blogspot.com