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Expedition to bursting, undersea volcano yields marvels

May 5, 2009
Courtesy National Science Foundation
and World Science staff

Sci­en­tists who have just re­turned from an ex­pe­di­tion to an erupt­ing un­der­sea vol­ca­no near the Is­land of Guam re­port that the vol­ca­no seems to be con­tin­u­ously ac­tive, has grown con­sid­erably in the past three years, and its ac­ti­vity sup­ports a un­ique bi­o­log­i­cal com­mun­ity thriv­ing de­spite the erup­tions.

An in­terna­t­ional sci­ence team on the ex­pe­di­tion cap­tured dra­mat­ic new in­forma­t­ion about the erup­tive ac­ti­vity of NW Rota-1.

Lava erupts on­to the sea­floor at NW Rota-1, creat­ing a cloudy, ex­treme­ly acid­ic plume. (Cre­dit: WHOI)

“This re­search al­lows us, for the first time, to study un­der­sea vol­ca­noes in de­tail and close up,” said Bar­ba­ra Ran­som, pro­gram di­rec­tor in the Na­tional Sci­ence Founda­t­ion’s Di­vi­sion of Ocean Sci­ences, which funded the re­search. “NW Rota-1 re­mains the only place on Earth where a deep sub­ma­rine vol­ca­no has ev­er been di­rectly ob­served while erupt­ing.”

Sci­en­tists first watched erup­tions at NW Rota-1 in 2004 and again in 2006, said Bill Chad­wick, an Or­e­gon State Uni­ver­s­ity vol­ca­nolo­g­ist and chief in­ves­ti­ga­tor on the ex­pe­di­tion. This time, howev­er, they found that the vol­ca­no in the Pa­ci­fic had built a new cone 40 me­ters high and 300 me­ters wide.

“That’s as tall as a 12-sto­ry build­ing and as wide as a full city block,” Chad­wick said. “As the cone has grown, we’ve seen a sig­nif­i­cant in­crease in the popula­t­ion of an­i­mals that lives atop the vol­ca­no. We’re try­ing to de­ter­mine if there is a di­rect con­nec­tion be­tween the in­crease in the vol­can­ic ac­ti­vity and that popula­t­ion in­crease.”

An­i­mals in this un­usu­al ec­o­sys­tem in­clude shrimp, crab, limpets and bar­na­cles, some of which are new spe­cies. “They’re spe­cially adapted to their en­vi­ron­ment,” said Chad­wick, “and are thriv­ing in harsh chem­i­cal con­di­tions that would be tox­ic to nor­mal ma­rine life. Life here is ac­tu­ally nour­ished by the erupt­ing vol­ca­no.”

A three-dimensional re­con­struc­tion of the NW Rota-1 vol­cano. The top is 540 me­ters (1,770 feet) un­der­water. (Cre­dit: NOAA)

Ve­re­na Tun­ni­cliffe, a bi­olo­g­ist from the Uni­ver­s­ity of Vic­to­ria, Can­ada, said that most of the an­i­mals are de­pend­ent on dif­fuse hot-wa­ter 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 are pro­fuse popula­t­ions of shrimp on the vol­ca­no, with two spe­cies able to cope with the vol­can­ic con­di­tions, she added.

“The ‘Loi­hi’ shrimp has adapted to graz­ing the bac­te­ri­al fil­a­ments with ti­ny claws like gar­den shears,” said Tun­ni­cliffe. “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 Loihi shrimp was pre­vi­ously known only from a small ac­tive vol­ca­no near Ha­waii, far away. It sur­vives on the fast-growing bac­te­ria and tries to avoid the haz­ards of the vol­can­ic erup­tions. Clouds of these shrimp were seen flee­ing vol­can­ic bursts, re­search­ers said.

Shrimp at NW Rota-1. (Credit: WHOI)

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,” Tun­ni­cliffe said.

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 un­der­wa­ter ven­ts, where some bi­ologists think life on Earth 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 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.

Sci­ent­ists con­trol a re­search sub from a ship. (Cre­dit: Ve­re­na Tun­ni­cliffe)

“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. “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, aboard the Uni­ver­s­ity of Wash­ing­ton’s ship R/V Thomp­son, the sci­en­tists made di­ves with Ja­son, a re­motely con­trolled sub op­er­ated by the Woods Hole Oceanographic In­sti­tu­tion. 

Chad­wick said that “it was amaz­ing how close Ja­son can get to the erup­tive ven­t be­cause the pres­sure at a depth of 520 me­ters [a­bout 1,700 feet] in the ocean keeps the en­er­gy re­leased from the vol­ca­no from be­com­ing too ex­plo­sive.” Some of the most in­tri­guing ob­serva­t­ions came when the vol­ca­no slowly pushed 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,” Chad­wick said.

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Scientists who have just returned from an expedition to an erupting undersea volcano near the Island of Guam report that the volcano seems to be continuously active, has grown considerably in the past three years, and its activity supports a unique biological community thriving despite the eruptions. An international science team on the expedition, funded by the National Science Foundation, captured dramatic new information about the eruptive activity of NW Rota-1. “This research allows us, for the first time, to study undersea volcanoes in detail and close up,” said Barbara Ransom, program director in the National Science Foundation’s Division of Ocean Sciences, which funded the research. “NW Rota-1 remains the only place on Earth where a deep submarine volcano has ever been directly observed while erupting.” Scientists first observed eruptions at NW Rota-1 in 2004 and again in 2006, said Bill Chadwick, an Oregon State University volcanologist and chief investigator on the expedition. This time, however, they found that the volcano had built a new cone 40 meters high and 300 meters wide. “That’s as tall as a 12-story building and as wide as a full city block,” Chadwick said. “As the cone has grown, we’ve seen a significant increase in the population of animals that lives atop the volcano. We’re trying to determine if there is a direct connection between the increase in the volcanic activity and that population increase.” Animals in this unusual ecosystem include shrimp, crab, limpets and barnacles, some of which are new species. “They’re specially adapted to their environment,” said Chadwick, “and are thriving in harsh chemical conditions that would be toxic to normal marine life. Life here is actually nourished by the erupting volcano.” Verena Tunnicliffe, a biologist from the University of Victoria, said that most of the animals are dependent on diffuse hot-water 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 are profuse populations of shrimp on the volcano, with two species able to cope with the volcanic conditions, she added. “The ‘Loihi’ shrimp has adapted to grazing the bacterial filaments with tiny claws like garden shears,” said Tunnicliffe. “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 Loihi shrimp was previously known only from a small active volcano near Hawaii, far away. It survives on the fast-growing bacteria and tries to avoid the hazards of the volcanic eruptions. Clouds of these shrimp were seen fleeing volcanic bursts, researchers said. 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,” Tunnicliffe said. 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 underwater vents, where some biologists think life on Earth 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 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. “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, aboard the University of Washington’s ship R/V Thompson, the scientists made dives with Jason, a remotely controlled vehicle operated by the Woods Hole Oceanographic Institution. Chadwick said that “it was amazing how close Jason can get to the eruptive vent because the pressure at a depth of 520 meters [about 1,700 feet] in the ocean keeps the energy released from the volcano from becoming too explosive.” Some of the most intriguing observations came when the volcano slowly pushed 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,” Chadwick said.