Antarctica’s Biggest Mysteries: Secrets of a Frozen World

By Andrea Mustain
Live Science

One hundred years ago this week, on a fine summer afternoon, Norwegian explorer Roald Amundsen and four travel-weary companions plunged a bright flag atop a spindly pole into the Antarctic ice, marking their claim as the first humans to set foot at the bottom of the world. The South Pole was theirs.

“That moment will certainly be remembered by all of us who stood there,” Amundsen wrote in his account of the arduous trek. On Dec. 14, 1911, two months after they set out from the continent’s coast, the men had reached their goal — a frozen plain of endless white in the middle of the highest, windiest, coldest, driest and loneliest continent on Earth.

A century after Amundsen planted the flag — beating out Englishman Robert Falcon Scott’s doomed expedition by a full month — an explosion of technological progress has transformed the scope of human knowledge of Antarctica.

Watchful satellites sail overhead; probing radar and lasers have allowed scientists to peer beneath the thick ice. And yet, in spite of the reach of these new tools, the continent still holds its secrets close. Many mysteries remain, and they are far more intricate and nuanced than the uncharted wilderness Amundsen and Scott confronted.

What is emerging from the research is that Antarctica is a far more dynamic place than anyone could have imagined a century ago — and that what happens there can have dramatic consequences for millions of people around the world.Now, instead of mapping new geographical discoveries, scientists are seeking to map the inner workings of the strange forces at play in Antarctica, from the biological mechanisms that allow tiny organisms to seemingly awake from the dead, to the little-understood forces that are gnawing away at the continent’s ice — with increasing vigor.

Antarctica is home to about 70 percent of the planet’s fresh water, and 90 percent of the planet’s freshwater ice. Two massive ice sheets, nearly 3 miles (4 kilometers) thick in some places, cover about 99 percent of the continental landmass. Including its islands and attached floating plains of ice, Antarctica is roughly 5.4 million square miles (14 million square km), about one-and-a-half times the size of the United States.

Not surprisingly, most Antarctic research is focused on the ice — what is happening under it, in it, and to it. And it was beneath the ice that scientists made one of Antarctica’s most screenplay-worthy discoveries: a sweeping kingdom of rocky slopes and liquid lakes, secreted under the icefor millennia.

During a 1958 mapping expedition, a Soviet team was trekking from the coast across the interior of the eastern half of the continent, and detonating explosives every hundred miles to measure the thickness of the ice. In the middle of the East Antarctic Ice Sheet, the team was traveling across ice 2 miles (3 km) thick, when something strange started to happen, according to Robin Bell, a geophysicist and professor at Columbia University’s Lamont-Doherty Earth Observatory.

“They suddenly found this very thin ice in the middle of the ice sheet, and they said, ‘Hey, there are mountains here,'” Bell told OurAmazingPlanet.

Big mountains. The team had stumbled upon what were later dubbed the Gamburtsev Mountains, a range of steep peaks that rise to 9,000 feet (3,000 meters) and stretch 750 miles (1,200 km) across the interior of the continent.

“It’s really hard to imagine that there are mountains under there. It doesn’t matter which way you spin — it’s pretty flat,” said Bell, who has studied the area for years. Yet, she added, the truly mysterious part of the hidden mountains is not that they exist, but how they still exist. The inexorable march of geological time erodes mountains away (if we came back in 100 million years, the Alps would be gone, Bell said) and the Gamburtsevs, at the ripe old age of 900 million to a billion years old, should have been worn down eons ago.

However, recent research indicates the mountains are a kind of geological do-over. “They were born a long time ago, but somewhere between 100 (million) and 200 million years ago, they had a renaissance,” Bell said.

It happened during a rifting event, Bell said, when tectonic forces were wresting apart continental masses during the breakup of Gondwana, the ancient supercontinent. At the time, the eroded mountains’ heavy roots apparently underwent a density change — as though a bar of solid chocolate suddenly morphed into the fluffy stuff inside a Three Musketeers bar — which buoyed the mountain range back up, “like a life preserver,” Bell said.

Exactly how that change in the Gamburtsevs’ root happened is a mystery. “That’s the biggest thing that has us scratching our heads,” Bell said. “We don’t know if the rifting added a little heat, added a little water — we know the rifting happened, and [the mountain range] popped up, but we’re still working on the question of how you make that phase change,” she said.

In among the Gamburtsev Mountains lies another enigmatic feature of the Antarctic: Lake Vostok — a pristine freshwater lake buried beneath 2.5 miles (3.7 km) of solid ice. About the size of Lake Ontario, it is the largest of the more than 200 liquid lakes strewn around the continent under the ice.

The lakes are largely created when heat from the Earth’s core melts the bottom of the ice sheet; the thick blanket of ice on top acts as insulation. Some of the lakes have been isolated for hundreds of thousands to millions of years, and scientists are racing to collect water samples; the sequestered lakes could be bastions of biological discovery, full of never-before-seen microbial life.

So far, nobody has managed to directly sample an Antarctic lake, but at least three projects — a Russian team, a British team and an American team — are tackling the problem. The Russians, at Lake Vostok, and the British, at Lake Ellsworth, may have samples by 2012.

And although lake water has so far eluded capture, scientists do have samples of the ice sheet itself, which, it turns out, sparks biological mysteries of its own.

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