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No. 87: May-Jun 1993

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The vent glow and "blind" shrimp

In 1988, when the research submersible Alvin was exploring those remarkable hydrothermal vents or "black smokers." Its CCD (Charge-Coupled Device) camera detected a ghostly glow emanating from the vents. Since this mineral-laden water gushing from these cracks in the deep-sea floor exits at 350-400C, the simplest explanation of the vent glow is that is is simply thermal radiation from the hot fluid. Indeed, color filters on the camera recorded a spectrum close to that of a 350C 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," Science, 259: 1124, 1993.)

From Science Frontiers #87, MAY-JUN 1993. 1993-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987