海洋科学家观测到最深的海底火山爆发

Scientists funded by the National Science Foundation美国国家科学基金会 (NSF) and NOAA美国国家海洋和大气局 have recorded the deepest erupting volcano yet discovered--West Mata Volcano--describing high-definition video of the undersea eruption爆发，喷发 as "spectacular壮观的，惊人的." "For the first time we have been able to examine, up close在很近距离内的, the way ocean islands and submarine volcanoes are born," said Barbara Ransom, program director in NSF's Division of Ocean Sciences. "The unusual primitive原始的，远古的 compositions of the West Mata eruption lavas火山岩浆 have much to tell us."

The volcanic eruption, discovered in May, is nearly 4,000 feet below the surface of the Pacific Ocean, in an area bounded by周围是，以……为边界 Fiji, Tonga and Samoa.

"We found a type of lava never before seen erupting from an active volcano, and for the first time observed molten熔化的，炽热的 lava flowing across the deep-ocean seafloor," said the expedition's chief scientist Joseph Resing, a chemical oceanographer海洋学家 at the University of Washington.

"It was an underwater Fourth of July, a spectacular display of fireworks nearly 4,000 feet deep," said co-chief scientist Bob Embley, a marine geologist at NOAA's Pacific Marine Environmental Laboratory in Newport, Ore.

"Since the water pressure at that depth suppresses the violence of the volcano's explosions, we could get an underwater robot within feet of the active eruption. On land, or even in shallow water, you could never hope to get that close and see such great detail."

Imagery includes large molten lava bubbles three feet across bursting into cold seawater, glowing red vents exploding lava into the sea, and the first-observed advance of lava flows across the deep-ocean floor.

Sounds of the eruption were recorded by a hydrophone水中听音器 and later matched with the video footage.

Expedition scientists released the video and discussed their observations at a Dec. 17 news conference at the American Geophysical Union (AGU)'s annual fall meeting in San Francisco.

The West Mata Volcano is producing boninite玻古安山岩 lavas, believed to be among the hottest on Earth in modern times, and a type seen before only on extinct volcanoes more than one million years old.

University of Hawaii geochemist地球化学家 Ken Rubin believes that the active boninite eruption provides a unique opportunity to study magma formation at volcanoes, and to learn more about how Earth recycles material where one tectonic plate地壳构造板块 is subducted除去，减去 under another.

Water from the volcano is very acidic酸性的, with some samples collected directly above the eruption, the scientists said, as acidic as battery acid or stomach acid.

Julie Huber, a microbiologist at the Marine Biological Laboratory, found diverse不同的，多种多样的 microbes even in such extreme conditions.

Tim Shank, a biologist at the Woods Hole Oceanographic Institution伍兹霍尔海洋研究所 (WHOI), found that shrimp were the only animals thriving in the acidic vent water near the eruption. Shank is analyzing shrimp DNA to determine whether they are the same species as those found at seamounts more than 3,000 miles away.

The scientists believe that 80 percent of eruptive activity on Earth takes place in the ocean, and that most volcanoes are in the deep sea.

Further study of active deep-ocean eruptions will provide a better understanding of oceanic cycles of carbon dioxide and sulfur硫磺 gases, how heat and matter are transferred from the interior of the Earth to its surface, and how life adapts to some of the harshest conditions on Earth.

The science team worked aboard the University of Washington's research vessel Thomas Thompson, and deployed Jason, a remotely-operated vehicle owned by WHOI.

Jason collected samples using its manipulator arms, and obtained imagery using a prototype still and HD imaging system developed and operated by the Advanced Imaging and Visualization Lab at WHOI.