Scientists probe ocean floor secrets

Web posted September 5, 1998

 Inside the Alvin

By Kathy Sawyer
The Washington Post

ABOARD DSV ALVIN -- Wedged inside a titanium sphere in his stocking feet, geophysicist H. Paul Johnson strained to peer out a five-inch porthole into a midnight dreamscape 1 12 miles below the surface swells of the eastern Pacific.

Johnson and Dudley Foster, pilot of their three-person research submarine, had been at work on the sea floor for almost six hours in badlands of jumbled black rock, deep fissures and hot towering fumaroles where oases of color and life bloomed crazily in the pitch dark.

Moving up a wall of black lava sculpted eerily into geometric shapes of fans and wheels, the divers had just discovered a previously unknown field of hot springs, populated by long white tube worms tipped with jaunty red plumes, scatterings of pale sea sponges and cucumbers, snow-white drifts of bacterial colonies and predatory spider crabs that seemed to watch the intruders with wizened ancient faces.

But the researchers' quarry lay even deeper. On a safari of sorts, the divers were hunting the smallest, most elusive game imaginable, in one of the most hostile environments on the planet. They were on an expedition to test a provocative theory: that there is a vast, clandestine horde of microscopic organisms thriving deep below the sea floor in Earth's crust. Mounting evidence, including newly discovered fossil signs of rock-eating microbes living almost a mile beneath the ocean bottom, suggests that this zone is a giant incubator of life.

This dive was part of an unprecedented effort to trap cells, molecules, DNA and other telltale evidence swept up in heated fluids that well up from this underworld.

Inside the cramped life-support sphere of the 17-ton Deep Submergence Vehicle (DSV) Alvin, Johnson, Foster and a Washington Post reporter along as an observer had been lowered that morning from the pitching deck of the mother ship, the research vessel Atlantis, into waves aglitter with sunlight. This was one of 15 deep-sea dives conducted during a 19-day cruise funded by the fledgling Life in Extreme Environments (LExEn) project of the National Science Foundation, the first such expedition with this theme as its major focus.

Atlantis would travel 1,125 miles during the hunt, criss-crossing a stretch of the undersea Juan de Fuca Ridge some 200 miles off the Oregon coast. The volcanically active ridge, where the landmarks have names like Hell, Inferno and Ashes, is part of the 46,000-mile seam that girdles Earth like stitching on a baseball. Here, the giant jigsaw plates of the outer shell pull apart and the planet's very heartbeat can be detected in pulses of sulfurous superhot water, flows of molten lava and swarms of seaquakes.

The plumbing system of hot-water (hydrothermal) vents that follows the ridge line has been a major focus of research since the first vent field was discovered by an Alvin team (including Foster) in 1977, with sooty black water gushing out at temperatures approaching 700 degrees Fahrenheit. Researchers were astonished to discover complex food chains built on ancient, previously unknown forms of heat-loving microorganisms that thrive in the perpetual night of the sea floor amidst the very elements of hell: fiery heat and brimstone (sulfur).

Scientists now regard these deep-sea hot spring systems as a tantalizing window into conditions that may have harbored primordial life forms on Earth billions of years ago. The findings helped revolutionize thinking about the nature of life and the ease with which it can arise on Earth, and on other worlds.

But even these bizarre sea floor oases were not deep enough for the LExEn researchers. If the theory is correct, said Johnson, there are microbes ``infesting the pores'' of the vast labyrinth beneath the ocean floor. After years of scattered attempts, Johnson and his colleagues have launched a multiyear effort to capture the first definitive biological evidence from this mysterious world, to understand its diversity, its habitats and habits.

``We have just awakened to the possibilities. It's still a frontier,'' biogeochemist James P. Cowen of the University of Hawaii, chief scientist of the July expedition, had said during a break on Atlantis' foredeck. ``It's not just that it's unexplored, and it's not just that it's so different, so extreme, an environment. What excites me is the fact that it's such a tremendous area and volume. It's vast. It's huge!''

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These explorations are physically daunting and logistically nightmarish. Temperatures on the deep ocean floor range from near freezing to beyond boiling-hot enough to melt Alvin's 3.5-inch thick acrylic portholes -- and pressures are thousands of times those at sea level. The pervasive darkness is heavy and aggressive, like a solid. Depending on the amount of sediment and other factors, it swallows Alvin's light beams before they travel more than a few feet or yards.

For these determined souls, however, the treks seemed almost workaday. Johnson, 58, a wiry and ebullient marine geophysicist from the University of Washington who sports an Einstein mustache, had made dozens of dives; and the coolheaded Foster, 52, a stocky former naval aviator, has become a figure of legend in the ``deep submergence'' community, with more than 500 deep-ocean dives to his credit.

They were part of an international research dive team of 18 men and women that ranged from graying senior scientists to graduate students and one wide-eyed college sophomore. A broad mix of disciplines, they included an organic geochemist, a molecular microbiologist, oceanographers and engineers. Each worked on a different piece of the complex puzzle while all were confined together on their floating laboratory, with their contrasting priorities and cultures.

They had at their disposal one of the most sophisticated research vessels in the world. The 275-foot Atlantis -- operated by the Woods Hole Oceanographic Institution (WHOI) in Massachusetts -- carries precision navigation, satellite telecommunications and bottom mapping systems, and a crew of 28 that included seven people dedicated to the tricky demands of maintaining and operating Alvin.

Even with all this support, the team contended with glitches in the navigation system, bad information about landmarks, poor visibility in sediment-clouded waters, an instrument that fell down a deep drill hole, a delay or two for repairs on Alvin, and a gale. With Alvin operations costing $25,000 a day, the researchers were in a perpetual race against time, working night and day.

Rushing from chaotic sites recently repaved with fresh lava flows to ancient landscapes softened by more than 3 million years worth of sediment, the team eked out precious bits of new knowledge: their initial analyses revealed a tidal process that affects sub-floor water circulation, for example, and they measured unexpectedly prodigious quantities of water and heat emerging -- not just from high pressure vents -- in widespread, diffuse flows rising through the flanks of the ridges. ``There was megawatts of heat (at the sea floor),'' Johnson said. ``I was astounded.''

``It's amazing to me that we know more about the surfaces of some other planets than we do about this one,'' said team member Robert Embley, of the National Oceanic and Atmospheric Administration's Vents program.

The strategy of the LExEn researchers may seem odd: they were searching for water in the depths of an ocean. But not just any water would do. They were determined to isolate the particular fluids that had percolated downward toward the planet's molten interior and now, in an altered state, were trickling, seeping or spewing back up again in high volumes, but at ``bath-water'' temperatures temperate enough to preserve biological evidence of the suspected microbial throngs far below.

``I call it small game hunting,'' said microbiologist Stephen J. Giovannoni, of Oregon State University, one evening. ``We've been talking about this for years, but nobody has ever done it before in this way.''

Fortunately for the explorers, given their stingy rations of piped-in light on the sea floor, even the temperate waters from below stand out visually against the chill seawater around them: they shimmer.

``They're chemically different,'' said chemist David Butterfield, of University of Washington, analyzing samples from the day's dive. For example, ``the fluids we got yesterday from one vent were bubbling like seltzer water.'' (Apparently the molten rock through which they had flowed was saturated with carbon dioxide, which carbonated them.)

To isolate the targeted waters and biological specimens from the ocean into which they flowed, under such harsh conditions, the team was constantly improvising. They re-engineered equipment overnight, repaired breaks, jury-rigged components -- often seemingly out of little more than duct tape and baling wire. ``If we knew what we were doing,'' quipped sleep-deprived technical assistant Michael Hutnak, also of UW, ``it wouldn't be research.''

On this dive, which started about 8 a.m. and took about 1 12 hours to reach bottom, the starboard view at first showed nothing but a dusty-looking gray-black expanse. Then the sub turned to port and a scene of irrational color leaped out of the darkness-mottled oranges, browns, reds, whites, pinks-inches from the ports.

``Tube worms!'' Johnson said. ``Jesus, what a spot!''

They had fallen into exactly the site they had planned, a field of warm water springs along the west wall of the axial valley, to the south of a major vent field called Endeavour. Humans had explored this particular spot just once before, Johnson noted. ``There's shimmering water below us.''

A pale pink spider crab with the dimensions of a manhole cover shifted his weight in the currents just outside the starboard port. A field of red-plumed tube worms undulated in the currents, and smaller reddish-brown palm worms, shaped like little hands, seemed to wave. Around and beneath them, cloaked in the ooze and grit of the bottom, smaller things wriggled and teemed.

With strains of Aretha Franklin playing on the sound system, Foster quickly had Alvin's port claw in motion, filling the air with the whine of tiny motors as he ``clearcut'' a semilevel patch in the tube worm jungle and moved boulders to even out the rough ground. His hands played expertly over dials and switches.

Soon he had collected some worms for the biologists waiting on the surface. Nearby, he deployed another odd, experimental device: a 2-foot-square thermal ``bio-blanket'' with wires and a data collector attached.

With a minimum of talk, Foster and Johnson worked intently down their list of tasks, using the floodlights sparingly to stretch Alvin's limited battery power. Occasionally, the dive coordinator on the mother ship would signal the sub, and Foster, his eyes glued to the front port, would reach behind him to key a rapid Morse code ``B'' for ``busy,'' letting the surface know things were okay.

Along the way, Johnson took a series of measurements intended to reveal regions where the rock below the sea floor was most porous and therefore provided the most habitable real estate for the team's quarry. To accomplish this, he had arranged for a complex gravity meter borrowed from the Navy's ballistic missile program to be installed inside the sub.

As they moved northward along the wall, the divers passed rock mounds resembling huge heads sporting what appeared to be dreadlocks, or giant powdered wigs. Each strand was a tube worm up to two or three feet long. In some places, there appeared to be thousands of the animals, disappearing into the gloom. Just as plants grow toward sunlight, the worms apparently angle their plumes in the direction of the flow of hydrogen sulfide ``food,'' giving each community a common angle of repose, team member Janet Voight explained.

The sub sailed past rat-tail fish, small clams, a slithering eel, a small octopus and a strange creature, possibly a jellyfish, that flared luminously in the shape of a star and then, in an instant, became a ball that seemed to jet away. The big spider crabs lined the route at intervals, like official greeters.

In the wastelands between the hot springs, there were leathery-looking expanses of lava flash-frozen by the cold sea in midflow. The flows had stalled in big folds and billows, almost like cumulus clouds, assuming strangely organic shapes: a bear; a sleeping person. As the divers worked their way further up the wall, the sculptures became sharper, as if carved by a power tool: huge chaotic stacks and piles of finely etched fans, wheels, orange slices and the like, each maybe three feet in diameter, but the whole pile perhaps several football fields in extent, with radial groves and concentric curves. These shapes are familiar to geologists, Johnson explained. ``These things erupt like a tube of toothpaste, then fracture into these 'pillow' wedges, like a slice of pie.''

Reaching the main Endeavour field, the divers flew past a rusty chimney, a tower six stories high, with wing-like flanges, built up by minerals deposited out of a fountain of hot fluids from below. Nearby, there was a shorter vent -- a ``black smoker'' -- that appeared to be puffing soot. (The colors of the vent emissions vary from scintillating clear, to gray, to black, even sometimes glowing like flame, depending on the temperature and pressure.)

It was about 2 p.m. when the explorers realized with delight that they had stumbled onto a new field of vents, high on the valley's west wall. Time itself seemed to fly past. An hour later, they crested the black ridge to turn eastward on what they intended to be a ``midwater flight'' across the valley floor, for a final gravity measurement.

``I'm seeing bottom!'' Johnson announced urgently.

Foster cursed softly as a rust-colored wall suddenly loomed in front of them. Alvin plowed into it. In the tunnel of illumination from their headlights, they could see clouds of reddish-orange debris billowing from the point of impact.

``That was an uncharted ridge,'' Johnson said. ``There's nothing on the map close to that (high). It beats me.'' Of course, he noted, the ``map'' for this terrain was only six months old, and patchy.

In a typical tradeoff for this line of work, Foster explained, the Alvin team had removed part of the sonar navigation equipment that might have given some warning of the unseen obstruction. That made it possible to accommodate Johnson's heavy gravity meter and still meet the sub's strict weight restrictions.

Unruffled, the veteran pilot backed the sub off with no harm done.

By 3:40, Johnson had completed his final gravity measurement and Foster dropped ballast, announcing, ``Weights away.'' Like the wizard's balloon departing Oz, the sub began to rise slowly toward ``home.''