NOAA SCIENTIST AND COLLEAGUES FIND HOT SPRINGS IN COLD WATERS

January 15, 2003 — One of the last places that NOAA scientist Ed Baker thought he would discover a dozen hydrothermal vents was in the icy cold Arctic Ocean, but that’s just where an international team of scientists found them. (Click NOAA map for larger view of Gakkel Ridge. Click here for high resolution version, which is a large file. Please credit “NOAA.)

“On the Gakkel Ridge, which is in the Arctic Ocean between Greenland and Siberia, we found evidence of nine to 12 hydrothermal vents along about 680 miles of the rift valley,” said Baker, a supervisory oceanographer at the NOAA Pacific Marine Environmental Laboratory in Seattle, Wash. Baker, who has been studying hydrothermal vents for almost 20 years, said the discovery was among the most remarkable and unexpected of his career.

The findings of Baker and his colleagues, including H.N. Edmonds of the University of Texas at Austin, and P.J. Michael of the University of Tulsa, will be published in the Jan. 16 issue of the science journal Nature. Using a combination of temperature and light measurements, along with an actual fresh sulfide chimney acquired in a dredging operation, the scientists present the first evidence for hydrothermal venting on the Gakkel Ridge.

“This discovery is significant because it is so unexpected,” Baker said. “The tectonic plates on either side of the Gakkel Ridge spread apart, or open, very slowly. In fact, it’s the planet’s slowest spreading ridge, moving at about a half an inch a year or less. We expected to find no more than four or five vent sites because this sluggish spreading rate creates far less volcanic activity than on most mid-ocean ridges.”

Hydrothermal vents, first discovered in 1976 on the Galapagos Ridge in the Pacific Ocean, are seafloor hot springs found along the 30,000 miles of global mid-ocean ridge that forms the Earth’s largest volcano. The hot spring water can reach 750 degrees Fahrenheit and is rich in dissolved chemicals. Colonies of unusual marine life, such as clams, tubeworms, and exotic microorganisms, cluster around these vents, feeding on the chemical soup that spews from the ocean floor.

Hot spring water rises and forms a plume above the vent, somewhat like smoke rising from a house chimney into the air. These plumes can be detected by oceanographic instruments, like Miniature Autonomous Plume Recorders (MAPRs), a self-contained instrument developed at PMEL to record temperature and light scattering caused by tiny mineral grains suspended in the water—clues that hydrothermal vents are on the seafloor below. (Click NOAA image for larger view of Miniature Autonomous Plume Recorder or MAPR.)

During a side-by-side expedition of the U.S. Coast Guard cutter Healy and the German Polastern icebreakers, which were conducting petrological sampling and geophysical surveys along the ridge in 2001, the scientists deployed MAPRs on all dredges and rock cores.

The scientists report that of 145 successful deployments of the MAPR, 119, or 82 percent, showed evidence of increased light scattering consistent with hydrothermal plumes. Of those, 58 showed temperature peaks that correlated to the light scattering.

Physical evidence came when fresh sulfide chimneys, which are created from the chemicals spewed into the water, and hydrothermally altered rocks were acquired during dredging operations. After photographs from a camera tow showed shimmering water and “abundant” biological activity in the area, the scientists named the area “Aurora.”

The unusual marine life found in Atlantic Ocean vent sites are “markedly different” from those found in the Pacific Ocean vent sites. Baker and his colleagues suggest that since the Gakkel Ridge is not connected to other parts of the mid-ocean ridge system south of Iceland, it is likely that new species of vent marine life await discovery.

“We are eager to return and see what is living down there,” Baker said.

The scientists note in their paper that “understanding the frequency and geological setting of hydrothermal venting along the mid-ocean ridge system is key to estimating the fluxes of heat and matter exchanged in these systems.” The NOAA VENTS program has been conducting research into hydrothermal vent systems since 1984, especially along the Juan de Fuca Ridge in the Pacific Ocean.

Relevant Web Sites
NOAA VENTS Program

Mid-Ocean Ridges

Scientists Return to Where Science Fiction Became Science Fact

Media Contact:
Jana Goldman, NOAA Research, (301) 713-2483
(Gakkel Ridge image courtesy of Peter Sloss of the NOAA National Geophysical Data Center. Photo of Miniature Autonomous Plume Recorder courtesy of Ed Baker of the NOAA Pacific Marine Environmental Laboratory.)