Health & Science
Nation & World
Friday, March 23, 2001, 12:00 a.m. Pacific
Close-up
Lake Vostok is miles beneath Antarctic ice, yet it's liquid - and might contain life
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by Robert Lee Hotz
Los Angeles Times
MICHAEL STUDINGER / THE LOS ANGELES TIMES
A scientist traverses the 2-mile-thick mantle of ice atop Antarctica's Lake Vostok, which may hold microbes unchanged from millions of years ago.
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. 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 2 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.
Conditions like other planets
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 (NSF) to study the microbial life of the Vostok ice.
Indeed, Lake Vostok's conditions appear so exotic that researchers at the Jet Propulsion Laboratory (JPL) believe they could offer a foretaste of how life might evolve in the frozen oceans of the Jovian moons Europa and Ganymede or in Mars' icecaps.
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 sea-level pressure.
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 University of Southern California Dean of Research Donal 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."
Will humans contaminate it?
Lake Vostok 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?
Despite herculean efforts by the NSF to minimize the impact of human activities in recent decades, people can hardly help but jeopardize the unique study areas that draw them here.
They contaminate the purest air on Earth with exhaust fumes from fleets of vehicles and aircraft. In a single season, one remote ecological study area logged 700 helicopter landings and takeoffs.
In the broadest sense, such concerns are central to any scientific endeavor.
In physics, the problem was formulated by Walter 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 Butler. "How do you sample something without changing it?"
Antarctic Andromeda Strain?
In a sense, Lake Vostok is a planet, isolated by extreme depths of ice 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 a bullet-shaped robot that melts through the icecap into the lake with instruments, cameras and perhaps even a robotic submarine on board. JPL scientists have tested a prototype.
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.
And there is at least a remote chance they may bring to the surface some pathogen against which humans have no immunity.
An international consortium of scientists has been brooding for four years over how 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? No one wants on their tombstone: 'I polluted Lake Vostok.' "
What the lake is like
Standing outside his tent, Studinger, the geophysicist, waved a gloved hand at the emptiness around him.
"We are right over the lake," he said. "The shoreline runs that way."
There is nothing obvious at the surface to indicate a lake, save a flatness so all-encompassing that it can be seen from space.
But after so many days poring over the 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 extends 5,400 square miles. Its deepest waters are 3,200 feet deep.
The overlying tide of ice creeps across the lake surface so slowly 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 atop a bed of sediments 229 feet thick, offering the possibility 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 advances in satellite surveying and radar studies - did anyone realize that Vostok was the biggest subglacial lake in the world and the largest geographic feature 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. Researchers have detected three moderate earthquakes that seem to be evidence of tectonic activity.
If so, geothermal vents at the lake bottom could provide the heat and minerals to keep the lake liquid and sustain life, just like the towering hydrothermal vents at the bottom of the Pacific Ocean off the Washington coast.
Moving methodically
It may be six months before scientists finish their analysis of all the radar readings, seismic plots and gravity measurements.
It could be a decade before Vostok's waters are breached.
"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."
Copyright © 2001 The Seattle Times Company
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