for National Geographic News
When British polar explorer Robert F. Scott discovered Antarctica's Taylor Valley in 1903 he described it as a "valley of the dead."
"We have seen no living thing, not even a moss or a lichen," he wrote in The Voyage of the Discovery, his book about the journey.
The valley is part of the McMurdo Dry Valleys, a cold, barren desert comprising 1,853 square miles (4,800 square kilometers) in southeastern Antarctica. It is the frozen continent's largest ice-free area and has become a focal point of scientific research in the 100 years since its discovery.
Contrary to Scott's 1903 observation, researchers have found that an ecosystem thrives in the soils, under the surface of frozen lakes, and even inside rocks. Nematodes, or worms, are the top predators.
"In the streams you have mosses and algal mats. In lakes you have phytoplankton and benthic algal mats, and the soils contain nematodes and other critters like rotifers and tardigrades," said Andrew Fountain, a geologist at Oregon's Portland State University.
Fountain is one of several scientists who regularly visit the dry valleys to study this life, trying to understand how it can survive in such a harsh environment.
"The dry valleys are an end member ecosystem. They provide us with an example of how an ecosystem—the organisms and the physical environment that supports them—can function on the edge of survivable conditions," said Peter Doran, an earth scientist at the University of Chicago in Illinois.
Doran, like Fountain and many other scientists, regularly visits the dry valleys as part of the National Science Foundation's McMurdo Long Term Ecological Research (LTER) program. There are 24 LTER sites spread around the world, allowing scientists to study ecological processes over long time scales. The dry valleys were added to the network in 1993.
100 Years of Same
John Priscu, an environmental scientist at Montana State University in Bozeman who has conducted research in Antarctica since the early 1980s, said the McMurdo Dry Valleys are "one of the oldest landscapes on the planet."
The Transantarctic Mountains block the seaward flow of the East Antarctic Ice Sheet from covering the region. Glaciers that grow from the surrounding mountains do not accumulate enough snow to fill the valleys with ice.
Researchers say that while lake levels have risen about 33 feet (10 meters) since Scott first set foot in the valleys 100 years ago and glaciers have shifted, the region has looked pretty much the same for the past 3 million years.
|
SOURCES AND RELATED WEB SITES
|
