An attempt to create a man-made, self-sustaining ecosystem in Arizona failed because humans simply do not understand all of the elegant intricacies that nature uses to keep the planet operating, researchers say.
Biosphere 2 was supposed to be a glass-enclosed copy of a pristine and smoothly functioning miniature Earth. But it evolved into a place choked with carbon dioxide and infested with uncontrollable weedy vines."It was the boldest attempt ever" to create a closed ecosystem, but it failed miserably, said David Tilman, a University of Minnesota scientist.
"This suggests that there are areas of nature that are sufficiently great mysteries that we don't know how to manage them or make them better," he said. "This is very humbling."
An analysis of the Biosphere 2 experiment by Tilman and Joel E. Cohen of Rockefeller University and Columbia University in New York is published Friday in the journal Science.
Built in Oracle, Ariz. at a cost of about $200 million, Biosphere 2 was designed to contain the soil, water, air, animals and plants needed for a self-contained living system capable of supporting eight humans without outside help.
Eight people were sealed into the Biosphere in September 1991. They were to be isolated for two years, raise their own food, breathe air recirculated by plants living with them and drink water cleaned by natural processes.
But in less than 18 months, it was clear the system was terribly out of balance, said Tilman. Oxygen concentration dropped from 21 percent to 14 percent, about the same level present at 17,500 feet and barely enough to keep the crew functioning.