Giant Mineral Deposit, Strange Life Forms Surround Hot-Water Vents Two Miles Down : ‘Detective Search’ for Geysers in Atlantic Yields Treasures for Scientists

Like treasure hunters probing the deep for sunken galleons, scientists spent years in search of hot-water geysers on the floor of the Atlantic Ocean. Then came the big find, with a bonus of a mineral deposit the size of the Houston Astrodome and forms of life never seen before.

“It was like a detective search,” said Peter Rona, a geophysicist for the National Oceanographic and Atmospheric Administration who led the search. “There were only a few of us who believed geysers should be present in the Atlantic.”

The geysers, more than two miles deep and spouting water at temperatures of up to 700 degrees Fahrenheit, are rich in dissolved metals. They are also home to never-before-seen eyeless shrimp, bacteria, a crab species and one creature that appears to be a “living fossil.”

Important Finds

The discoveries of the Atlantic geysers and similar boiling vents found earlier in the Pacific are among the more important scientific finds of the century, Rona said.

Undersea geysers have potential applications in mining, energy and biotechnology industries, he said.

Rona’s decade-long quest enlisted researchers from the Massachusetts Institute of Technology and Woods Hole Oceanographic Institute. Last summer, the expedition videotaped the geysers and scooped up samples of the life forms from a special deep-dive submarine along the mid-Atlantic ridge, about 1,000 miles due east of Miami and 12,000 feet below the surface.

“There’s a valley in the middle of the ridge,” Rona said. “In this valley we found a mound, the size and shape of the Houston Astrodome, a giant mineral deposit created by the geysers.”

Ocean Floor Expands

Ridges in the Atlantic and Pacific oceans are places where the ocean floor expands. This happens at a rate of about 10 inches yearly in the Pacific. For unknown reasons, the Atlantic floor expands at only about one inch a year.

To counter this expansion, the Earth also contracts, via earthquakes.

“The sea floor is leaky; it’s full of cracks,” Rona said. Along cracks, cold ocean water seeps deep into the Earth, where it is heated and absorbs dissolved metals from volcanic rock.

The heated water shoots back out in mineral-packed jets of the geysers. When the hot flow hits cold ocean water, the dissolved metals cool and crystallize so quickly that geysers look like they are spouting a black smoke plume. The minerals fall back around the geyser, forming mounds that teem with life.

Found in Pacific

Pacific geysers, also full of minerals and new life forms, were found in 1979. But many researchers did not think they would occur in the Atlantic because the ocean floor expands so slowly.

“The bandwagon had gone to the Pacific,” Rona said.

But his joint research group confirmed the existence of Atlantic geysers and mineral deposits at least 10 times larger than those in the Pacific, he said.

The Atlantic mound of iron, copper, gold, silver and zinc--all mixed in with sulfides--glitters with a dusting of iron sulfide (fool’s gold).

“For the first time, geologists can see mineral deposits at the time of formation,” Rona said. “They can get clues to aid the exploration on land . . . which could lead them to the richest deposits.”

Mining Too Costly

Undersea mining is too costly now, but Rona predicts that that will change as land supplies dwindle.

The Atlantic geyser mounds contain about 5 million tons of minerals, Rona said.

“These are resources of the future,” he said. “It’s a living laboratory of the processes that have gone on through Earth’s history, and the history of life.”

While geologists are thrilled with the geysers, biologists are excited about the life forms around them. In the Atlantic, millions of eyeless shrimp live crammed around the toxic hot jets.

“It’s intrigued biologists who don’t know how they live,” Rona said. “They get as close to the jet as they can. They’d be boiled shrimp if they went too close.”

New Species

“They belong to a new species,” said Woods Hole researcher Cindy VanDover. The shrimp are odd because they live so crammed together and have no eyes. Scientists are not sure what they eat but think it is sulfides or bacteria, she said.

The shrimp resemble species found near the Pacific geysers. Biologists wonder how they evolved so similarly while so far apart.

Near Pacific vents, researchers found huge “tube” worms, standing up to six feet high, and giant clams. They also found methane-producing bacteria and others that love temperatures hot enough to cook other species.

Some bacterial finds have been put to work in laboratories making enzymes for such biological industry projects as breaking down DNA, said Woods Hole microbiologist Holger Jannasch.

Won’t Fall Apart

“Companies want these badly,” he said, explaining that the bacteria can produce enzymes that will not fall apart when heated.

No giant creatures have been found in the Atlantic vents, but they have yielded heat-loving bacteria that could produce enzymes, Jannasch said.

During the summer of 1985, Rona cruised over the sea floor on the government ship Researcher and used a variety of methods to look for the geysers, such as measuring dissolved manganese and measuring light scattered by minerals suspended in water. The shipboard measurements indicated where the geysers were and a remote video camera was sent down.

Special Submarine

In the summer of 1986, Rona videotaped the geysers from the special deep-dive submarine ALVIN, which can squeeze in three passengers for the two-hour trip to the ocean floor. The geysers are two miles below where the sun shines, where the pressure is 400 times the pressure of air.

Once on the bottom, ALVIN’s arms, like those developed for exploration on spaceships, reached out and scooped up samples of soil and creatures.

Among the samples were the eyeless shrimp, but they did not survive the pressure changes on the way up. Organisms brought to the surface need to be put in a container that simulates their own environment.

Hexagonal Shapes

When Rona saw the hundreds of silver-dollar-sized, hexagonal shapes photographed around the outer mound area, he thought photographers were playing darkroom jokes on him.

They weren’t. But no one could identify the shapes. A German paleontologist thinks the shapes are similar to holes left by Paleodyctum nodosum , a worm that lived 70 million years ago.

“These appear to be living fossils,” Rona said.

The “fossils” were carefully placed in a container that should preserve them, but the container has not yet been opened by scientists at Woods Hole.

Theories Changed

Ocean floor geysers have changed some theories about the seas.

“The ocean is a chemical soup,” Rona said. “It was thought rivers washed the ingredients in. But it’s not just a big bathtub. Many of the ingredients come from the sea floor itself.”

Rona and other scientists are planning their next trip to the bizarre undersea world sometime in 1989.

“This just opens up this world,” Rona said. “Now we have to understand it--the global impact.”