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On 1 January 1996 (1), Columbia University took over scientific management of Biosphere 2, a 3.15-acre closed ecosystem in Oracle, Arizona, containing soil, air, water, plants, and animals. Since then, the facility has been seeking suggestions for its future research mission from a broad range of scientists. In September, Columbia's Wallace Broecker, Biosphere 2's new chief scientist, convened a committee of ecologists, plant physiologists, and population geneticists to propose possible biodiversity experiments at Biosphere 2 (2). These have yet to be evaluated, in part because the new director of Biosphere 2, William C. Harris, has just moved to Columbia from the National Science Foundation. Nevertheless, the committee on biodiversity experiments was struck by some fundamental lessons already learned from Biosphere 2.
No existing closed-environment facilities for ecological research approaches the size and sophistication of Biosphere 2: the original airtight footprint covered 13,000 m2 and enclosed 204,000 m3. Despite the enormous resources invested in the original design and construction (estimated at roughly $200 million from 1984 to 1991) and despite a multimillion-dollar operating budget, it proved impossible to create a materially closed system that could support eight human beings with adequate food, water, and air for 2 years. The management of Biosphere 2 encountered numerous unexpected problems and surprises, even though almost unlimited energy and technology were available to support Biosphere 2 from the outside. Isolating small pieces of large biomes and juxtaposing them in an artificial enclosure changed their functioning and interactions rather than creating a small working Earth, as originally intended.
The staff of Biosphere 2, and several reports (3-5), revealed to the committee numerous examples of surprises that had been encountered since the facility began its first "mission," the widely publicized enclosure of eight Biospherians from 1991 to 1993. By January 1993, 1.4 years after material closure of Biosphere 2, the oxygen concentration in the closed atmosphere fell from 21% to about 14% (see...