[FWD: A Sea of Mystery, Frozen in Time [LONG]]

From: Rodent of Unusual Size (Ken.Coar@Golux.Com)
Date: Thu Apr 19 2001 - 03:16:15 PDT

What odds they find archaea in the lake?

#ken    P-)}

Ken Coar <http://Golux.Com/coar/> Apache Software Foundation <http://www.apache.org/> "Apache Server for Dummies" <http://Apache-Server.Com/> "Apache Server Unleashed" <http://ApacheUnleashed.Com/>

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A Sea of Mystery, Frozen in Time

Miles below the antarctic ice, a freshwater lake may harbor ancient life. The dilemma: how to study it without destroying it.


VOSTOK, ANTARCTICA -- At the coldest spot on Earth, Michael Studinger is mapping a world he cannot see.

Around him stretches a snow-scape as smooth as a starched shirt, so empty of landmarks that any sense of scale or distance is lost in the white. But hidden miles beneath the icecap on which he stands is a freshwater lake as long as Lake Ontario and as deep as Lake Tahoe--its untouched waters a time capsule from more than a million years ago.

For 18 days in January, the young geophysicist from the Lamont-Doherty Earth Observatory in New York and a dozen colleagues crisscrossed the ice sheet with radar and other sensors. They bounced a low-frequency signal at bedrock three times every second, neatly outlining the riddle below and setting the stage for an international effort to probe its mysterious depths.

The pristine waters of Lake Vostok, as it is called, have been isolated by a continental shield of ice two miles thick for millions of years. The lake may harbor microbes unchanged from a time when Antarctica was as green as the rain forests of Brazil, offering scientists a unique test tube of life from a primordial era. A Desert of Ice

The lake--discovered in 1996 after researchers combined decades' worth of seismic studies, radar surveys and satellite imaging--is "one of the last unexplored frontiers of our planet," said ecologist John Priscu at Montana State University. He is leading an effort funded by the National Science Foundation to study the microbial life of the Vostok ice.

Indeed, the conditions in Lake Vostok appear so exotic that researchers at the Jet Propulsion Laboratory believe it could offer a foretaste of how life might evolve in the frozen oceans of Jupiter's moons Europa and Ganymede or in the icecaps of Mars.

No one knows how this lake stays liquid in a region where the temperature recently fell to minus 132 degrees Fahrenheit, the lowest ever recorded on Earth. The temperature has not risen above freezing for millions of years.

No one knows how any organism, cut off from air, sunlight or any apparent source of life-sustaining energy, could survive in its frigid currents or under such crushing pressure--more than 360 times the atmospheric pressure at sea level.

If the lake does contain life, "it would not be an overstatement to say it could be one of the biological finds of the millennium," said USC Dean of Research Donal T. Manahan, a biologist who is chairman of the polar research board of the National Academy of Sciences.

The opportunity to sample such an ancient, untouched habitat, Manahan said, "comes once in a million years."

And whatever mysteries Lake Vostok may preserve, it embodies a troubling question at the heart of every human activity in Antarctica: How can researchers study a place so unique and delicate without destroying it?

Antarctica, the last open continent, is a world of killing extremes and unexpected grace, a desert of ice where compasses lie and it is usually too cold to snow.

Sun dogs--vast sparkling halos of ice crystals in the air--wheel in the sky. Penguins and seals dawdle on the sea ice. Mirages dance on the horizon. Volcanoes fume under the ice. Lake water fizzles with laughing gas.

Despite herculean efforts by the U.S. National Science Foundation to minimize the impact of human activities in recent decades, people can hardly help but jeopardize the study areas that draw them here.

Indeed, this is a land where biologists gingerly walk from rock to rock, lest they unintentionally trample rare soil colonies of microbes or sparse lichen. Drums of human waste routinely are shipped thousands of miles to California. No one dares touch the birds or marine mammals because, under the terms of an international treaty, they could be fined or even deported.

Nevertheless, to reach remote study sites, they contaminate the purest air on Earth with exhaust fumes from fleets of motorized vehicles and aircraft. In a single season, one remote ecological study area in Antarctica's Dry Valleys logged 700 helicopter landings and takeoffs.

Although NSF researchers conscientiously recycle tons of trash and waste every year, hundreds of thousands of gallons of raw sewage spew into coastal waters every day from McMurdo, the main U.S. base in Antarctica.

It may be another two years before a waste water treatment plant will be built.

Scientists worry too about the long-term impact of the research tools they employ, from the stream gauges that monitor meltwater flows and the radioisotopes used as tracers in Antarctica's few streams and lakes, to the remote-controlled robots that explore under the ice shelf.

In the broadest sense, such concerns are central to any scientific endeavor.

In physics, the problem was formulated mathematically by Werner Heisenberg as the uncertainty principle, which suggests it is impossible to separate the experimenter from the experiment. At least at the level of quantum physics, no one can measure a particle without disturbing it and altering its properties in unexpected ways.

"Lake Vostok is the biological equivalent of the Heisenberg uncertainty principle," said atmospheric chemist James H. Butler. "How do you sample something without changing it?"

Butler is one of a team of scientists from the National Oceanic and Atmospheric Administration camped a mile from the South Pole this year to analyze the ancient air preserved in the snow there.

To avoid having their work ruined by fumes blown from the U.S. South Pole station nearby, they are conducting their research at the far edge of a special clean-air quadrant. The area is upwind of the station's busy runway, where cargo planes took off and landed 262 times last year.

Rarely, however, is the scientific paradox posed by human presence framed so starkly as in the effort to explore Lake Vostok.

"It is very special because it is a fossil lake, where we do not know if some biological community might have survived for a million years or more," said Mario Zucchelli, manager of the Italian Antarctic Program.

In a sense, Lake Vostok is a planet in the ice, isolated by extreme depths of frost rather than by the cold vacuum of space.

The robot probes being considered to explore Vostok are the same as those being designed to probe the icy interiors of Ganymede and Europa.

One plan envisages the use of a bullet-shaped robot that melts its way through the icecap into the lake with instruments, cameras and perhaps even a robotic submarine on board. JPL scientists have tested a prototype of such a probe at the Monterey Bay Aquarium.

But when they lower a robot probe into the lake, scientists could risk contaminating its waters with microbes from the surface or altering its chemistry with hydraulic fluids or grease from the probe itself. If they do successfully sample the lake, there is at least a remote chance that they may bring to the surface some pathogen against which humankind has no natural immunity.

An international consortium of scientists has been brooding for four years over how best to proceed --or whether to proceed at all.

"Here you risk having to go out and sacrifice some part of the planet in order to learn more about the planet," said University of Hawaii oceanographer David Karl, who discovered microscopic life forms in the ice above Lake Vostok. "It is an ethical dilemma.

"How do you bring up a sample without contaminating the lake?" said Karl. "No one wants on their tombstone: 'I polluted Lake Vostok.' " A Hidden Landscape

Standing outside his tent, Studinger of New York's Lamont-Doherty observatory waves one gloved hand at the emptiness around him.

"We are right over the lake," he said. "The shoreline runs that way."

His humid breath crystallizes in icicles on his beard as he speaks. Bundled in a scarlet parka, he stands out like a tulip in the snow. It is 32 degrees below zero. The snow underfoot crunches like cornmeal on glass.

A few hundred yards away, a ski-equipped U.S. Air National Guard cargo plane thunders on idle as the camp's fieldworkers load canisters of trash and other waste aboard for recycling or disposal in the United States.

The austral summer air is so frigid that the air crew does not risk turning off the engines, in case the hydraulic fluid congeals or pistons become so chilled that they crack. It routinely gets cold enough for diesel fuel to freeze, for dripping oil to form icicles.

There is nothing obvious at the surface to indicate anything of a lake, save a flatness so all-encompassing that it can be seen from space.

But after so many days poring over the chiaroscuro of seismic plots and radar readings, Studinger can easily see the contours of that hidden landscape in his mind's eye.

The lake is crescent shaped, with a steep escarpment almost 3,000 feet high along its northern shoreline and broad shoals to the south. As best anyone can tell, the lake is 124 miles long and covers 5,400 square miles. In its deepest basin, its waters are 3,200 feet deep.

The overlying tide of ice creeps across the lake surface so slowly that it takes 15,000 years for it to cross from shore to shore, sagging imperceptibly as it slides over the water, then buckling as it grounds on the opposite bank.

The lake water is cradled on a bed of sediments 229 feet thick, offering the possibility that they contain a unique record of the climate and life in Antarctica before the icecap formed.

In all there are at least 76 subglacial lakes in Antarctica. There is even a lake under the South Pole.

But not until 1996--with the advent of advances in satellite surveying and radar studies--did anyone realize that the lake under the ice at Vostok was the biggest subglacial lake in the world and the largest geographic feature on Earth discovered in the past 100 years.

Like Lake Baikal in Siberia and Lake Malawi in East Africa, it may have formed in a rift valley created by the shifting of tectonic plates, according to geophysicist Robin Bell at the Lamont-Doherty Earth Observatory, who oversees the $4.5-million NSF mapping effort. Researchers have detected three moderate earthquakes in the area that seem to be evidence of tectonic activity.

"It is not a piece of old, quiet crust," said Bell. "It is a place where the Earth is moving."

If so, geothermal vents at the lake bottom could provide the heat and minerals to sustain life forms, just like the towering hydrothermal vents at the bottom of the Pacific Ocean.

It may be six months before Bell and Studinger finish their analysis of all the radar readings, seismic plots and gravity measurements they collected at Vostok.

The new map is a mosaic pieced together from systematic aerial surveys conducted by a chartered Twin Otter aircraft operated by the Support Office for Aerogeophysical Research (SOAR), an NSF-funded project at the University of Texas at Austin's Institute for Geophysics.

For people working out of small, isolated camps like Vostok in the interior of Antarctica, the twin-engined DeHavilland aircraft is a kind of aerial dog sled. On this mission, it carried a ton of radar, laser altimeter, gravity sensors and other geodetic gear.

The crew flew three flights a day, skimming for four hours at a stretch about 1,100 feet above the ice along a predetermined grid measuring 205 miles by 105 miles, explained SOAR operations manager Thomas Richter.

"The Twin Otter we fly is the only one like it in the world," said Richter. "No one else collects so much data or makes such a complete set of measurements simultaneously."

So thin and cold is the air at Vostok--at an altitude equivalent to 12,800 feet--that each stabbing breath holds only 60% of the oxygen in the air at sea level. The heart sprints. The mind numbs.

Some of the researchers slept with oxygen bottles. Most took pills to stave off altitude sickness. So arid is the atmosphere that they packed IV drip bags to ensure that no one became dangerously dehydrated.

Even so, four people were evacuated by aircraft when conditions became more than they could medically bear.

Life, children once were taught, is best lived in moderation.

And until recently, biologists focused their attention on those life forms that shared humanity's conservative taste for the temperate climatic and chemical conditions of middle Earth.

With that in mind, researchers long considered Antarctica's polar plateau, with its extreme cold, aridity and high levels of ultraviolet radiation, as sterile as an autoclave.

But now they realize that life is easily taken to extremes, in Antarctica and elsewhere. They're Everywhere

Microbes can be found in rocks a mile underground and in the clouds overhead. Some microbes make their home in toxic waste, while others shrug off radiation or survive in brine five times saltier than the sea. Many species of single-celled creatures readily grow in the absence of oxygen, warmth and light.

And, if one recent published research report can be believed, at least one spore-forming microbe survived unthinkable extremes of time, reviving after being dormant for 250 million years.

So many simple organisms thrive in conditions lethal to conventional life forms that biologists now suspect that life must have evolved under conditions dramatically different from those so hospitable to humankind today.

The first single-celled citizens of Earth may have taken form during a primordial time of fire and ice about 750 million years ago when the entire planet looked something like Lake Vostok, some biologists speculate.

They envision a primitive "snowball Earth" encrusted in a rind of ice that covered pockets of water kept liquid by the heat from geothermal vents. There, protected from space by the ice and invigorated by the energy of the hot vents, microbes adapted and evolved in an intricate dance with extremes of heat and cold.

Today some heat-loving microbes thrive in temperatures above the boiling point of water in hot springs and deep-sea volcanic vents. A few microbial species find temperatures less than 194 degrees Fahrenheit too cold to reproduce.

At the other extreme, bacteria living in the sea ice around Antarctica find it too hot to breed if the temperature gets much above 53 degrees. Bacteria discovered in the gravel under alpine glaciers in Switzerland live quite comfortably at the freezing point of water.

In the interior of Antarctica, with winds so violent and ice so thick that no root can hold, life ekes out a surprisingly rich existence.

Some microbes find refuge from the cold between the grains of porous stone.

Others live and die in the minute gaps between snow crystals at the South Pole, biologist Ed Carpenter at San Francisco State University and USC environmental biologist Douglas Capone discovered.

Those one-celled organisms were comfortable living in prolonged darkness and at temperatures so low that liquid water--normally a prerequisite for life on Earth--is almost completely absent.

The ambient temperature in the snow where they were found hovered just above 1 degree Fahrenheit. Their habitat was continually bathed in high levels of sterilizing ultraviolet radiation common in the polar region.

To survive in such conditions, these seemingly simple creatures each inherit four copies of their genome and an elaborate DNA repair mechanism that compensates for the destructive genetic effects of radiation and desiccation.

In ice samples taken a few hundred feet above Lake Vostok--at a depth of 11,778 feet below the surface--scientists recently discovered dormant colonies of microbes.

At that depth, the ice itself turns from cloudy, tightly packed crystals to larger, almost transparent "gem" ice. Researchers believe that is a sign that the ice is composed not of ancient compacted snow but of frozen water from the lake itself.

Using DNA fingerprinting techniques, ecologist Priscu and his colleagues determined that these bacteria are closely related to species of soil microbes found elsewhere in Antarctica. So far, no one knows whether these bacteria actually lived in the lake and evolved there, or sifted down through the ice from the surface over half a million years.

If microbes do survive in the lake, they are micro-denizens of perpetual darkness with no obvious source of food and under a weight of ice so heavy that the water in which they swim contains almost no dissolved oxygen, methane or other gases.

"The more we look, the more we see that life can adapt to more extreme conditions than we ever imagined," Carpenter said. "It makes microbial life on other planets seem a little more plausible." A Russian Outpost

At the far end of the landing strip--at the very edge of the ice horizon--is a sliver of snow-drifted buildings and radio towers known as Vostok Station--a Russian scientific outpost on the ice above the lake that researchers have manned almost continuously for 40 years.

The station sits over the south end of the lake at the precise geomagnetic South Pole, surrounded by decades' worth of discarded machinery, waste and rubbish.

In the annals of Antarctica, the privations of the Russian scientists at Vostok have made the station's name a synonym for hardship.

Over the years, the Russian scientists here have endured temperatures colder than parts of Mars, dwindling support and reflexive skepticism about the quality of their research from colleagues in Europe and the United States.

Recent financial cutbacks in the Russian Antarctic Program have left the station with half its normal staff. The austerity measures also mean that Vostok can be resupplied just once a year. Fuel and food are hauled overland by tractors about 900 miles from the coast. Mechanical breakdowns sometimes prevent the overland tractor trains from reaching Vostok.

When the supply column stalled halfway to Vostok late last year, the U.S. Air National Guard airlifted emergency supplies to keep the Russian supply train moving.

"They are hanging by a thread," said Scott Borg, who oversees the NSF research effort at McMurdo.

It was Russian scientists at Vostok Station who discovered the lake and who first realized its unique potential.

Now they hope that the international effort to explore the life in the lake might benefit their own faltering research program.

By coincidence, the Russians have already drilled through most of the icecap over Lake Vostok. They had no idea the lake was there when they began decades ago.

In the most ambitious drilling program ever undertaken on the southernmost continent, the Russian scientists produced the world's deepest ice core, containing an irreplaceable chemical record of more than 400,000 years of Earth's changing climate and atmosphere. They did not learn of the lake's existence or appreciate its importance until the project neared completion.

But in 1998, as the drill reached within a hundred yards of the surface of the lake, they deliberately stopped. No one wanted to risk contaminating the water.

To keep the ice hole from freezing shut as they worked, however, the Russian scientists over the years pumped it full of aviation fuel and Freon. Now there is too much drilling fluid to be safely pumped out of the hole, stored aboveground, recycled or removed, Russian officials have reported.

At least 60 tons of the toxic chemicals sit in a narrow column that reaches to within a few hundred feet of the lake, like a needle poised above a bubble of expectations.

It could be five years before all the difficulties have been resolved and a project can be organized to explore the lake, and a decade before its pristine waters are breached, U.S. officials said.

"Lake Vostok is an international treasure," said Karl Erb, director of the NSF Office of Polar Programs, which oversees most research conducted in Antarctica.

"We have to convince not just the scientific community but the entire world that we can do this without contaminating the lake."

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