Posted on 09/09/2003 11:04:45 AM PDT by presidio9
hat started as a hunch is now illuminating the origins of life.
A few years back, Dr. Derek R. Lovley and colleagues at the University of Massachusetts found that a few kinds of bacteria used iron as a means of respiration (just as humans use oxygen to burn food) and that a surprising but common byproduct of this form of microbial breathing was magnetite, a hard black magnetic mineral.
The scientists wondered if hidden swarms of microbes might account for the vast deposits of magnetite that dot the earth and sea.
So they turned to one of the strangest, most ancient of environments — the deep sea's volcanic gashes, where mineral-rich waters hot enough to melt lead gush forth to nourish riots of life ranging from microbes to eight-foot-long tube worms. From the deep Pacific and other sites, the scientists obtained many samples of hot fluids.
To their surprise, they found that all the heat-loving microbes, known as hyperthermophiles, could breathe iron and make magnetite. Not only that, but one type broke the high-temperature record, thriving at an astonishing 250 degrees — far above the boiling temperatures usually associated with sterilization. The alien organism was judged to be among the most primitive forms of life ever discovered.
"It was a crapshoot," Dr. Lovley said of the hunt. "The surprising thing was that all the hyperthermophiles turned out to use iron."
That discovery, he and other scientists say, suggests that all life on earth may have originated from a microbe that breathed iron — potentially a key insight to learning about the chemical pathways that eons ago led to the dawn of biologic evolution.
In the quarter century since the discovery of the hydrothermal ("hot water") vents, scientists have found a world's worth of life: hundreds of unfamiliar species, new genera, new families and whole new orders. Together, they constitute major gains in measures of global biologic diversity, and they have gained a name: the dark biosphere.
Today in Los Angeles, filmmakers, drawing on waves of such excitement, are releasing a big-screen movie that celebrates the vents.
"It has been a passion for a number of us," said Dr. Richard A. Lutz, a Rutgers biologist who aided the film and the original discovery. "We've been enamored by the vents ever since."
The ocean floor was once thought to be a wasteland that possessed no light, no heat, no plants and very little life, if any.
That image shattered in 1977, when oceanographers working deep in the Pacific found bizarre ecosystems lush with clams, mussels and long tube worms.
When brought to the surface, the creatures smelled of rotten eggs, a sign of sulfur. It turned out that the ecosystem's main energy source was sulfur compounds emitted by the hot vents, in particular hydrogen sulfide. The primary producers (like plants on land) were tiny microbes thriving on volcanic heats and chemical energies rising from the earth's interior.
The dark ecosystems forced scientists to conclude that not all life on earth depends on the sun's energy or on photosynthesis.
As similar communities were found in the deep, intrigued scientists theorized that the vents were perhaps windows on a deep microbial world, a hidden biosphere extending for miles into the earth's crust, with a total mass rivaling or exceeding that of all surface life. Even stranger, they suggested that life on earth might have begun in such realms, nurtured by a steady diet of hot chemicals.
Since those frenetic early days, ocean scientists have found not only scores of such deep oases but strong evidence that they do in fact represent the tip of a very old, very large ecosystem. Recent papers report censuses of the tribe's most fundamental members — microbes.
"We find bugs pretty much everywhere we look," said Dr. John A. Baross, a biologist at the University of Washington who studies hyperthermophiles and used a deep-sea robot to retrieve the water sample containing superhot organism.
(Excerpt) Read more at nytimes.com ...
The primary reason for posting science threads is to keep supernaturalists entertained?
It's evolving!
In my case it's because I find them interesting.
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