( The hydrothermal vents were miles from ...)Hydrogen and methane provide raw energy for life at 'Lost City'

Scientists who named the spot Lost City knew they were looking at something never seen before when the field was serendipitously discovered in December 2000 during a National Science Foundation expedition to the mid-Atlantic.

This week in Science, researchers publish for the first time findings about the gases produced at Lost City and the organisms that make their living off them. Both are so different from so-called black-smoker hydrothermal vents that they may provide a whole new avenue for looking for the earliest life on Earth and for signs of life on other planets, according to Deborah Kelley, University of Washington oceanographer and lead author of the Science article.

Microorganisms at Lost City are living in fluids with alkaline pH that ranges from 9 to 11, which is nearly as caustic as Liquid-Plumr, Kelley says. This compares to the previously studied black-smoker vents where organisms are well adjusted to acidic pHs.

Further, she says, Lost City microbes appear to live off bountiful methane and hydrogen. Absent is carbon dioxide, the key energy source for life at black-smoker vents. And there is little hydrogen sulfide and only very low traces of metals, on which many of the microbes at the other kind of vents depend. The difference in what's available is because water circulates through the Lost City hydrothermal vent field via serpentinization, a chemical reaction between seawater and the mantle rock on which Lost City sits. The resulting fluids are 105 F to 170 F. At the other kind of field, first discovered in the early 1970s, volcanic activity or magma drives venting and fluids can reach 700 F. The vents at such sites are often referred to as black smokers because some e
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