Sea Chimneys Hold Clues on Life in Harsh Habitats

July 20, 1998

Sea Chimneys Hold Clues on Life in Harsh Habitats

By JOHN NOBLE WILFORD

EATTLE -- Like the astronauts who brought back the first rocks from the Moon 29 years ago this month, an expedition of scientists returned to port here this weekend with exotic souvenirs but this time from a world even stranger than anything lunar and more geologically and biologically alive: the ocean floor.
For the first time, the scientists had raised from the depths of the Pacific Ocean huge sections of rocky chimneys that rise from the sea floor like stalagmites, spewing toxic chemical-laden smoke. The black smokers, as they are called, are where scalding water percolating out of Earth's interior forges a wealth of minerals and supports colonies of bizarre forms of life that thrive in the harshest of environments.
The scientists' catch, displayed on Saturday on the deck of the Thomas G. Thompson, a University of Washington research vessel, included four such chimneys, 5 to 7 feet tall and 1,200 to 4,000 pounds. They were mainly dark and rough, like meteorites just fallen from the sky. But they were also marked by seams of white minerals and patches with a golden glitter, which might have sent Forty-Niners rushing to celebrate at the nearest saloon under what would have been the mistaken impression that they had struck it rich.
Two of the largest chimneys were recovered while still hot and teeming with small worms, sea spiders and limpets.
Countless worms inside tiny tubes, though dead on arrival at the surface, clung to the chimney surfaces like a fringe. Still alive inside were microbes that may be among the most primitive forms of life found. Scientists were already making cultures of the microbes in laboratory dishes.
"The important thing is not the size of the smokers," said Dr. Edmond A. Mathez, chairman of earth and planetary sciences at the American Museum of Natural History in New York. "It's that we raised something alive and hot. We can now study something about the maximum conditions at which life can exist."
Expedition scientists said they expected the chimneys and specimens to provide important clues about how life can originate and persist in such extreme conditions, in volcanic vents beneath the sea where temperatures reach several hundred degrees and without sunlight. Their investigations could shed light on the theory, controversial but winning support, that life on Earth might have originated in such sea-floor cauldrons. An abundance of life there suggests that life may be more widespread than once thought.
Speaking after the ship's arrival, Ellen V. Futter, president of the American Museum, one of the expedition sponsors, said, "These amazing structures and the unusual life forms they support offer tantalizing implications about the origins of life on Earth and the possibility of life on other planetary bodies, or the possibility that sunlight-based life as we know it here on Earth is quite rare."
Dr. John R. Delaney, a University of Washington oceanographer and the expedition's chief scientist, had his eye on the extraterrestrial implications. "Our research will help us look for life off the planet," he said. "In the long term, that's the essential point of what we are doing."
The search for life elsewhere has focused on Mars, encouraged recently by findings in meteorites from the planet and evidence of widespread surface water there in the past. But scientists are increasingly interested in Europa, a moon of Jupiter. The Galileo spacecraft has found considerable evidence that beneath the ice surface of Europa lies a deep ocean warmed by internal heat and a possible haven for simple life.
The three-week expedition was mounted by the University of Washington and the American Museum. The chimneys will be analyzed in the university's laboratories and made available for study by international scientists. At least one of the smokers will be shipped to the American Museum for study and eventual display in its new hall of earth science, to open next spring.
A Canadian ship joined the search, and it was a Canadian remotely operated vehicle that traveled more than a mile to the sea floor to find the chimneys, separate them with a chain saw and attach them to an 8,000-foot line to be hauled to the surface. A camera on the vehicle videotaped the life around the smokers and the recovery. A section of one chimney is to be sent to the Royal Ontario Museum in Toronto.
The world of submarine hot springs bubbling with sulfide minerals and gases from Earth's interior and crawling with exotic life was unknown until 1977, when the first such site was discovered off the Galapagos Islands. Two years later, off Mexico, the first pinnacle-shaped black smokers were observed. They appeared to be a common phenomenon along the volcanically active ridges under the Pacific.
From photographs scientists have measured one chimney to be as high as 140 feet. Only a few small pieces of the chimneys had been retrieved until now. The expedition made its haul near the Juan de Fuca Ridge, 180 miles off the coast of Washington and British Columbia.
In conversations and interviews on the final leg of the voyage, scientists described the geology of the samples they had retrieved. The bulk of the chimney structures consisted of metal-bearing sulfur compounds, like the minerals pyrite, chalcopyrite, wurtzite and sphalerite, with silica and the white calcium sulfate mineral anhydrite.
Chalcopyrite is a copper iron sulfide that glitters like gold.
The scientists could not estimate the age of the smokers, but they appear to build quickly. Five days after the last retrievals, remotely controlled video showed 2 or 3 feet of new minerals had accumulated on top of the chimney stumps.
Dr. John A. Baross, a University of Washington microbiologist, said the two largest chimneys were still hot internally when they were brought on deck. Heat-loving, or thermophilic, microbes were still growing on the surfaces and interiors.
"We have lots and lots of positive cultures of these microbes," he said. "This cruise will add a great deal to our quest for what is the upper limit of temperatures at which life can exist."

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