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Science Frontiers ONLINE No. 38: Mar-Apr 1985 |
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Life In The Dark
Two most interesting discovery have been made recently in deep ocean waters. First, abundant plant life has been found at depths of up to 268 meters, well beyond the 200-meter limit biologists had set based on the availability of sunlight. It wasn't difficult to discount photosynthetic life at 268 meters, because light there is only 0.0005% that at the surface. But there it was; and it may be found even deeper now that we've taken off the blinders.
(Littler, Mark M., et al; "Deepest Known Planet Life Discovered on an Uncharted Seamount," Science, 227:57, 1985.)
The second discovery came at 10,000 feet in the Gulf of Mexico. There, scientists in the submersible Alvin found a well-developed community of large clams, crabs, mussels, and tube worms, which closely resembles those around the Pacific hydrothermal vents. These life colonies do not use sunlight at all, nor do they depend on other life forms based on solar energy. They employ chemosynthesis, and the hydrogen sulfide and other substances in the vented waters replace sunlight. Although there are no obvious vents at the Gulf of Mexico site, the waters there contain plenty of hydrogen sulfide, indicating seepage from somewhere. The life forms are all new to science, although they resemble those in the Pacific.
(Anonymous; "Worms without Vents," Oceans, 17:50, September/October 1984.)
Comment. Question: how do non-mobile life forms travel the great distances from one vent or seepage locale to another? It seems as if we are just beginning to appreciate life's colonizing capabilities. Who knows what life forms subsist in the hot geothermal fluids circulating deep in the earth's crust?