The Dry Valleys: Antarctica’s Ice-Free Region
Polygons of permafrost, liquid lakes that leak from towering glaciers, stark-white ice emerging from rocky Grand Canyon-like landscapes: this is the McMurdo Dry Valleys region of Antarctica.
Ecologically, a desert is an ecosystem that receives less than 10 inches of precipitation per year. Despite the fact that 98 percent of Antarctica is covered with ice, the continent is the world’s largest and driest desert; it is classified as a polar, or cold, desert rather than a hot desert like the Sahara. The Dry Valleys region, comprising most of the two percent of Antarctica not covered in ice, is one of the most unique ecosystems in the world. It receives little to no measurable precipitation each year; it is ice-free because of the high mountain ridge that blocks the flow of the East Antarctic Ice Sheet into the region; and the ground is permanently frozen.
Scientists from many disciplines, including biology, geology, chemistry, seismology and glaciology, are working together in the Dry Valleys to determine the ancient history of the region and the climatic changes that shaped it. The National Aeronautics and Space Administration (NASA) is studying how the Dry Valleys region compares to the surface of Mars three million years ago. You can do a virtual fly-through of Taylor Valleys, one of the Dry Valleys, courtesy of the National Science Foundation’s Long-Term Ecological Research project there: http://www.mcmlter.org/video/fly_through.htm.
The Dry Valleys house several lakes, including Don Juan Pond, which contains so many salts and minerals that it never freezes, even in sub-zero Antarctic temperatures.
Because the Dry Valleys lack rainwater and heat to aid in decomposition, animals that die there become mummified. Contaminants can remain there long after they are leaked, so environmental protection is of the utmost importance. Everything brought into the Valleys – including human waste – must be collected and shipped back to the country of origin, and no natural materials such as rocks or animal fur may be removed. The McMurdo Dry Valleys area was one of the first regions designated as an Antarctic Specially Managed Area (ASMA).
View photos and descriptions of Ann and Dan’s trip to the Dry Valleys at Dan’s Wild Wild Weather blog and below.