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By Andy Parsons Special to ABCNEWS.com The McMurdo Dry Valleys form the largest, year-round ice-free area on the Antarctic continent. It’s one of the planet’s most extreme environments. Temperatures average minus 13 degrees Fahrenheit. It gets less precipitation than the Sahara Desert, and powerful winds scour the land.
Life in the dry valleys is scarce, and any life you do find tends to live at the very edge of survival. The McMurdo Dry Valleys is one site that’s part of the Long Term Ecological Research (LTER) Network, a collaborative research effort funded by the National Science Foundation. One goal of the program is to better understand how ecosystems work. The research project looks at the major features of the dry valley ecosystem — the soils, the lakes, the streams and the glaciers. Each year during the austral summer (which is wintertime in the Northern Hemisphere), a team of about 30 researchers descend on the dry valleys.
This harsh environment remains virtually unexplored. By studying such a simple system, uncomplicated by the thousands of interactions between organisms found in temperate locations, we can better understand how all ecosystems function. Ice covers the lakes year-round, streams flow for only a few weeks each year, glaciers lose more water by evaporation than by melting, and soils face low temperatures and virtually no precipitation. Microorganisms, mosses, lichens and relatively few groups of invertebrates are present in the dry valleys; higher forms of life are virtually nonexistent. The soils I’m studying are very dry, similar to a coarse sandy beach, with a few rocks thrown in here and there. The organisms living in the soil are bacteria, yeasts, protozoa, nematodes and the occasional tardigrade and rotifer, both minute water animals. All of these things are too small to see with the naked eye. In most dry valley soils, you find only two or three nematode species at the top of a very simple food chain, and for that reason have been described as the “lions of the dry valleys.” In most temperate soils you would find more than a hundred species of nematode alone, not to mention the thousands of other organisms in the food chain. In Antarctica, we get to see what effect these microscopic creatures have on each other and on the overall system, without the normal larger beasts getting in the way to confuse the issue. 
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S U M M A R Y A soil biologist looks at the microscopic creatures at the bottom of the world to better understand how all ecosystems function.
E - M A I L U S Write to Andy Parsons 
W E B L I N K S
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