National Geographic Today
In the McMurdo Dry Valleys of Antarctica, worms are the most sophisticated life-forms around.
The valleys are so cold, arid and bleak that they are used to simulate conditions on Mars. No plants, birds or insects survive there. But beneath the rocky, frozen polar soil dwell microscopic worms called nematodes that may be harbingers of the effects of climate change throughout the world.
Every year since 1989, Diana Wall, a soil ecologist and director of the Natural Resource Ecology Laboratory at Colorado State University in Fort Collins, has come to the valleys to help identify and understand the spectrum of microscopic creatures that make up the soil's food web. She wants to know what will happen to this web if the climate changes.
"Four out of five animals on Earth are nematodes," Wall says. About 15,000 species have been identified, and Wall suspects that there may be thousands if not millions more to discover. Common nematode parasites include roundworm and ringworm.
Nematodes and other microfauna help boost soil fertility by accelerating decomposition and decay, recycling the nutrients and making them available to plants. "Basically you have got to care about soil if you want to eat," Wall says.
For scientists, a challenge is to gauge how the microscopic soil creatures will react to warmer global temperatures.
"If you raised the temperature in Central Park and tried to understand all the changes that were happening, you couldn't do itthere are too many organisms and too many species," says Byron Adams, Wall's colleague, an evolutionary biologist and nematode expert at Brigham Young University in Provo, Utah.
Worms in Suspended Animation
For example, handfuls of dirt from the base of six plants in the tall-grass prairies of Kansas yielded more than 350 species of nematode, with thousands of other species and millions of individuals.
In the Dry Valleys the food web is basic. The main players are the bacteria that live in the soil and the three species of nematode that feed on them.
Taylor Valley, a 40-minute helicopter ride from McMurdo Station, the largest research facility in Antarctica, is one of the coldest, driest places on Earth, with temperatures averaging 4 degrees Fahrenheit (20 Celsius); and precipitation equivalent of less than four inches (10 centimeters) of rain per year.
"This place is a natural laboratory," says Rob Jackson, a global change biologist at Duke University in Durham, North Carolina, who is familiar with Wall's work. "With fewer species it is much easier to see the cause and effect when you manipulate the ecosystem."
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