In 1977, scientists aboard the research submarine Alvin, half a mile below the surface of the Pacific west of Ecuador, discovered exotic hydrothermal vents on the sea floor. Tubeworms, clams, and bacteria, whose primary source of energy is sulfur compounds from the vents, were flourishing nearby. Since then, dozens of other vents have been found at various undersea locations.
This has led Jack Corliss, a marine biologist now working at NASA's Goddard Space Flight Center, to suggest that these vents might have provided an environment where the beginning of life might have been nurtured.
"The thing about hot springs is that they provide a nice, safe, continuous process by which you can go from very simple molecules all the way to living cells and primitive bacteria," he told Discover magazine.47
Some popular periodicals, long on speculation but short on specifics, have promoted this concept. However, when science writer Peter Radetcky asked origin-of-life researcher Miller about it, he got undisguised hostility. "The vent hypothesis is a real loser. I don't understand why we even have to discuss it," an exasperated Miller told him.48
Bradley also was skeptical when I brought up this theory. "Granted, the vents might provide an unusual energy source that could prompt some chemicals to become reactive," he said. "But it never even addresses the assembly problem. This theory does nothing to solve the problem of how to put together the building blocks of life in the right sequence and with the right connections."
What's more, he said, experiments by Miller and Jeffrey Bada at the University of California at San Diego have suggested that the high temperatures of these super heated vents would destroy rather than create complex organic compounds.
Explained Bradley: "It's now thought that all of the water in the ocean is periodically recirculated through these vents. If you were finally getting some molecules that were beginning to get bigger and more complex, they would be so fragile that they would get destroyed by the heat when they were recirculated. That means the time scale for chemical evolution would be shrunk dramatically. The vents would make you go back and start over at pretty short intervals-and that would work against the development of life."
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