Team Explores Undersea Volcano

April 20, 2009
By Bernice Santiago
Pacific Daily News; Hagåtña, Guam, USA

Just 60 miles north of Guam, an undersea volcano is erupting.

NW Rota-1 is located in the Marianas Volanic Arc, one of the most active volcanic chains on the planet.

A team of scientists and engineers have been gathering data on NW Rota-1 for the past two weeks.

They were aboard the R/V Thompson research vessel, which was docked briefly at Apra Harbor on Friday. They found the volcano erupting when they visited the area several days ago. The Marianas arc expedition is one of several scientific investigations put together by the National Ocean and Atmospheric Administration's Pacific Marine Environmental Laboratory.

NW Rota-1 has been erupting almost continuously for five years. The NW Rota-1 volcano is crawling with shrimp, and has grown 130 feet in height since scientists visited in 2006.

"Our observations here are some of the first direct observations of an erupting submarine volcano ever," wrote NOAA oceanographer Sharon Walker in an e-mail to the Pacific Daily News. "We have made several visits to this volcano since 2003, with the first confirmation of an active eruption during our 2004 visit."

The scientists analyzed samples of seawater around the volcano, measured the rock and deposits, and studied the microbe, shrimp, and limpet populations living atop NW Rota-1.

"Studying the chemistry of these volcanoes can help provide a better understanding of how excessive amounts of carbon dioxide affect marine environments," Walker added.

The site of the eruption is 1,700 feet below the ocean surface.

"There have been no reports that I am aware of that this eruption has had any effect on Rota, Guam or any of the surrounding islands," wrote Walker.

Walker and her colleagues observed "billowing clouds of yellow and white smoke" made of sulfur, carbon dioxide bubbles streaming out of the vent, and "ash and pebble-sized rocks raining out of the plume."

Thriving species

Underwater lava flowing out of a volcano blooms into pillars and bulbs, solidifying from the contact with the cold ocean. Some of that hardened rock shatters, and the fragments shoot up into the plume. Gaseous sulfur and water vapor in the magma cool and condense into liquids during the eruption. The miniscule drops of liquid sulfur form great clouds that billow from the volcano, according to an entry by volcanologist Kathy Cashman on the expedition's website.

Scientists also found two species of shrimp, limpets and barnacles thriving in the sulfur, carbon dioxide, and heat produced by the volcano. The animals survive on the complex, diverse communities of microbes that blanket the volcano.

"The extreme acidity of the fluids coming out of the vent alter the rocks and limit what sort of animals can live here," Walker noted, adding that scientists watched a fish drop abruptly to the sea floor after accidentally swimming into the volcanic plume.

Instruments

Along with sonar systems, plume sensors, and hydrophones -- instruments that detect sound waves from an underwater source -- the researchers are also using a Jason ROV, a remotely operated vehicle that can collect oceanic data in conditions inhospitable to humans.

Jason ROVs have been used to explore sunken warships and trading ships, along with deep ocean explorations of the Earth's crust and microbial life forms living at those extreme depths, according to the Woods Hole Oceanographic Institution, where the remote explorer was invented. The Jason ROV approached within 10 feet of a major eruptive site on NW Rota-1.

Scientific studies of NW Rota-1 will continue.

"The instruments we plan to leave behind will monitor the area continuously for the next year," wrote Walker.

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