OREGON STATE UNIVERSITY

Scientists return to erupting undersea volcano; find massive cone, new species

05/05/2009

NEWPORT, Ore. – 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.

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 meters high and 300 meters 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.

“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.

“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.

“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.

“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 sulfur, formed when sulfur 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 meters (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.

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

Credit Information: Video is restricted for use by news media, non-commercial broadcast only. Copyright © Woods Hole Oceanographic Institution, All Rights Reserved. For commercial licensing, contact media@whoi.edu. Credits: Bill Chadwick, Oregon State University; Advanced Imaging and Visualization Lab, Woods Hole Oceanographic Institution. (For more information, contact Bill Chadwick, 541-867-0179, bill.chadwick@oregonstate.edu)

• Time-lapse movie of the seafloor shaking and rocks being shoved away from the eruptive vent as new lava slowly forces its way to the surface (video speeded up 4 times, no audio). http://video.cws.oregonstate.edu/cflkmx-hiq.mp4

• A rocky outcrop on a ridge of the volcano provides habitat for two species of shrimp specially adapted to live in the extreme chemical environment found near the eruptive vent (no audio). http://video.cws.oregonstate.edu/zqgnc-hiq.mp4

• Jason prepares to sample the eruption plume with an intake held in one of its manipulator arms as ash rains down on the vehicle. Later a curtain of CO2 bubbles rises in front of the camera during another eruptive pulse. http://video.cws.oregonstate.edu/ssflg-hiq.mp4

• The Jason ROV approaches the Brimstone eruptive vent at the top of the new 40-meter high cone (no audio). http://video.cws.oregonstate.edu/cgfgjh-hiq.mp4

• The seafloor quakes and heaves as new lava slowly erupts. http://video.cws.oregonstate.edu/swscn-hiq.mp4

• Seafloor shaking and rocks being shoved away from the eruptive vent as new lava slowly forces its way to the surface. http://video.cws.oregonstate.edu/snzvb-hiq.mp4

• White billowing plume full of sulfur and ash erupts out of Brimstone vent (no audio). http://video.cws.oregonstate.edu/tqfvm-hiq.mp4

• Volcanic gases stream out of the Brimstone eruptive vent: clear bubbles are CO2, while the white cloud is dominated by sulfur (no audio). http://video.cws.oregonstate.edu/sfpkv-hiq.mp4

Still images and captions are available at the links below:

• 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) http://oregonstate.edu/dept/ncs/photos/seafloor.JPG

• Two unique species of shrimp that are adapted to the harsh conditions are among the animals that live at the erupting NW Rota-1 submarine volcano. (photo credit: copyright Woods Hole Oceanographic Institution) http://oregonstate.edu/dept/ncs/photos/shrimp1.JPG

• The smaller shrimp (most of the individuals in this photo) graze bacterial mat from the rocks, whereas the larger shrimp (top, middle) are a new carnivorous species that preys on the smaller one. (photo credit: copyright Woods Hole Oceanographic Institution) http://oregonstate.edu/dept/ncs/photos/shrimp2.JPG

• At Brimstone vent, ash erupts as well as volcanic gases, including clear bubbles of carbon dioxide and a yellow plume which is filled with tiny droplets of molten sulfur, which has also been deposited on the rock in the right foreground. (photo credit: copyright Woods Hole Oceanographic Institution) http://oregonstate.edu/dept/ncs/photos/brimstone.JPG

• The Jason manipulator arm takes a sample of the eruption plume (upper right) at NW Rota-1 submarine volcano. The dark rocks in the left foreground are lava that was recently erupted. (photo credit: copyright Woods Hole Oceanographic Institution) http://oregonstate.edu/dept/ncs/photos/plume.JPG