8 results found.
... : Jan-Feb 1991 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects An Amusing Assemblage Of Anomalies We don't read much about "waterguns" in the modern scientific literature, but a century ago Nature published many ear-witness accounts of them. These muffled detonations heard near the coasts of almost all the continents are believed by some to be caused by eruptions of methane from the seafloor. The same eruptions probably also account for the myriads of "pockmarks" found in the sediments of shallow seas. Whether this outgassing of methane comes from shallow accumulations of organic matter or from deep within the crust is still debated. Here, geophysics merges with biology. Recently, a group of researchers discovered a large (540 square meters) patch of chemosynthetic mussels in a brine-filled pockmark, at a depth of 650 meters, off the Louisiana coast. The mussels grew in a ring around the concentrated brine. The mussels harbor symbionts which consume the methane still seeping up through the brine from a salt diapir (a massive fingerlike intrusion 500 meters below the brine pool. The origin of some diapirs is not well-understood.) The mussels get the oxygen they require from the ordinary seawater covering the dense brine. Like the biological communities surrounding the "black smokers" and other ocean-floor seeps, the brine-filled pockmark community includes several species of shrimp, crabs, and tube worms. We have here another example of the astounding ability of lifeforms to take advantage of unusual, even bizarre niches. (MacDonald, I ...
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... -carrying comets or meteorites. P.J . Boston et al have investigated one possible Martian ecosystem: "We have reexamined the question of extant microbial life on Mars in light of the most recent information about the planet and recently discovered nonphotosynthetic ecosystems on Earth -- deep sea hydrothermal vent communities and deep subsurface aquifer communities. On Mars, protected subsurface niches associated with hydrothermal activity could have continued to support life even after surface conditions became inhospitable. Geochemical evidence from the SNC meteorites and geomorphological evidence for recent volcanism suggest that such habitats could persist to the present time...We suggest a possible deep subsurface microbial ecology similar to those discovered to depths of several kilometers below the surface of the Earth." (Boston, Penelope J., et al; "On the Possibility of Chemosynthetic Ecosystems in Subsurface Habitats on Mars," Icarus, 95:300, 1992.) Comment. Although Boston et al speak in terms of microscopic Martian life, there is no reason why chemosynthetic life forms could not be large -- perhaps even large enough to leave traces on the Martian surface! Reference. Our catalog The Moon and the Planets has an entire chapter (AM) on Martian geology and possible biology. Details here . From Science Frontiers #82, JUL-AUG 1992 . 1992-2000 William R. Corliss ...
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... Science Frontiers ONLINE No. 18: Nov-Dec 1981 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Life's origin within the earth?Biologists usually hark back to warm, sunlit swamps and tidal pools when contemplating the origin of life. Lately, Hoyle has proposed a cosmochemical origin (see OR DID IT DRIFT IN FROM WITHOUT? ). Few look within the earth. Yet, when Mt. St. Helens erupt-ed it essentially sterilized all lakes and ponds in the immediate area as far as known life forms were concerned, and then introduced previously unknown chemosynthetic bacteria. At least, this is one interpretation. Scientists at Oregon State University found the waters around the volcano to be teeming with these bacteria, up to a billion per drop. The bacteria resemble nothing in the local soil but do seem related to bacteria existing around Precambrian volcanos. (Anonymous; "Secrets of Life in a Volcano?" Boston Globe, July 14, 1981.) Comment. Were the new bacteria in the volcanic ejecta or had they just gone unnoticed in the soil? Could the hot rocks, geothermal brines, and restless magmas beneath our feet be the real cradle of terrestrial life, with photosynthesis-dependent surface species being relatively unimportant to the big picture? From Science Frontiers #18, NOV-DEC 1981 . 1981-2000 William R. Corliss ...
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... Science Frontiers ONLINE No. 88: Jul-Aug 1993 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Whale falls: stepping stones across the ocean abysses Unique biological communities flourish at widely separated "oases" on the deepsea floors, where hydrothermal vents supply the energy and chemicals necessary for life. Here are found free-living bacteria, tube worms, molluscs, and several other species that prosper without the benefit of photosynthesis. These chemosynthetic, thermal-vent communities are separated by thousands of kilometers of sea-floor "desert." Yet, the species involved are similar worldwide and must, at some time, have crossed these wide, forbidding expanses. One possible mechanism for this mysterious dispersion came in 1987, when the research submersible Alvin chanced upon the remains of a 21-meter whale at a depth of 1,240 meters off California's coast. The whale's skeleton was covered with bacterial mats like those at the hydrothermal vents. Also sustained by the carcass were mussels, snails, and worms; all in all, a community much like those at the vents. Furthermore, many of the species partaking of the whale's energy and chemical resources are not normally found in that part of the Pacific. Subsequently, more "whale falls" with attached biological communities were found elsewhere. Calculations suggest that whale falls are more common that one might suppose -- perhaps occurring with average spacings of only 25 kilometers. They could very well be the stepping stones that allow hydrothermal vent communities to disperse across the ...
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... nonexistent. Still more recently, similar life forms have been found clustered around oil seeps in the Gulf of Mexico. As at the hydro-thermal vents, the clams, worms, crabs, and other organisms depend mainly upon the ability of bacteria to chemosynthesize -- the primary energy source being hydrogen sulfide in the vented water. (Paull, C.K ., et al; "Stable Isotope Evidence for Chemosynthesis in an Abyssal Seep Community," Nature, 317:709, 1985; Also: Weisburd, S.; "Clams and Worms Fueled by Gas?" Science News, 128:231, 1985.) Comment. Since the earth's crust seems honeycombed with fissures and rivers of life-sustaining fluids, subterranean life may be as common as the abyssal chemosynthetic life at the vents and seeps. This versatility of life signals us that we should look for life wherever there is energy of any kind. From Science Frontiers #43, JAN-FEB 1986 . 1986-2000 William R. Corliss ...
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... filters on the camera recorded a spectrum close to that of a 350 C plume. But the deep-sea shrimp camped around the vents have raised second thoughts. The shrimp, only a few inches long, live in the perpetual darkness of the miles-deep vents. They do not need and do not have ordinary eyes. Rather, they sport a mysterious organ on their backs that is connected to their brains by a nerve-fiber bundle much like an optic nerve. This organ is packed with the same light-sensitive pigments found in the eyes of surface creatures. Despite its unusual location on the shrimp, it is an "eye" of sorts. But of what use is it in the Stygian abysses? To find, perhaps, vent glows that betray the presence of chemosynthetic food sources. If this is so, the shrimps' optical organ, which is most sensitive in the blue-green portion of the spectrum, is badly mismatched to the infrared of the vent glow. It is a truism that nature is a perfectionist and would not tolerate such bad design. The eyes of animals are always well-tuned to their ways of life. Some possible conclusions: (1 ) The vent glows are not entirely due to thermal radiation; (2 ) The shrimps' organ is tuned to "something else"; and (3 ) The vent-shrimp link is recent, and evolution has not yet had time to fine-tune the shrimps' "eye." (Travis, John; "Probing the Unsolved Mysteries of the Deep," ...
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... Science Frontiers ONLINE No. 90: Nov-Dec 1993 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Depths Of Ignorance Oceanographers have been heard to complain that science knows more about the surface of Mars than it does about the topography of the deep ocean floors. Marine biologists, however, have even more reason to feel slighted. To illustrate, the usual picture painted of the abyssal terrain beyond the continental shelves and slopes is one a a frigid biological desert -- endless plains of sterile muck, broken once in a while by oasis-like deepsea vents, where weird tube worms thrive amidst clouds of chemosynthetic bacteria. This is a highly misleading portrayal. The situation, in fact, recalls what happened when biologists first released clouds of insecticides in rain forest canopies, thus precipitating a deluge of uncataloged insects into collecting nets waiting below. Now, instead of a mere million species of insects worldwide, entomologists are thinking perhaps 10 million or more. Will the same diversity prevail in the deepsea muck? C.L . Van Dover believes so: "Away from the vents, in the great ocean plains, life is much less dramatic and often scaled down to minute proportions -- threadlike worms, tiny snails, delicate, transparent clams. Yet, the diversity of animals in the cold abyssal muds, it now appears, may rival the celebrated biodiversity of the tropical rain forests." We now know virtually nothing about this fauna, how it survives, and how it evolved. Millions of undescribed species may be awaiting discovery by ...
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... Science Frontiers ONLINE No. 107: Sep-Oct 1996 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Rock-Based Life Virtually all biology textbooks insist that all terrestrial life ultimately depends upon sunlight for its survival. The ecosystems clustered around the deep-sea vents and the bacteria found in deep aquifers demonstrate that the sun is not essential to life -- chemical energy does just fine. In fact, the domain of chemosynthetic life has now been extended to a Romanian cave that has apparently been almost completely sealed off from surface influences for 5.5 million years. Air does leak in through tiny cracks, and water partially fills the cave. What is most remarkable in this sunless, sealed ecosystem is its biodiversity: 48 animal species, including 33 brand-new species. The roster includes isopods, a millipede, a centipede, a water scorpion, and a leech. Of course, bacteria and fungi thrive there, too. In contrast to unsealed caves, where insects, bats, and other sources of food filter in from the surface, life in the Romanian cave seems to derive entirely from hydrogen sulfide present in the cave's rocks. This compound is consumed by microorganisms, which are then grazed by cave occupants higher up the food chain. A NASA scientist has called Movile cave a "Mars analog site." And indeed it might be, for Mars has plenty of rocks and subsurface water. (Skinrud, E.; "Romanian Cave Contains Novel Ecosystem," Science News, 149: 405, ...
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