Biosphere 2
With a size comparable to two and a half football fields, it remains the largest closed system ever created. The glass facility is elevated nearly 4,000 feet (1300 m) above sea level at the base of the Santa Catalina Mountains, about a half hour outside of Tucson.
Biosphere 2 contained representative biomes: a 1,900 square meter rainforest, an 850 square meter ocean with a coral reef, a 450 square meter mangrove wetlands, a 1,300 square meter savannah grassland, a 1,400 square meter fog desert, a 2,500 square meter agricultural system, a human habitat, and a below-ground level technical infrastructure. Heating and cooling water circulated through independent piping systems and passive solar input through the glass space frame panels covering most of the facility, and electrical power was supplied into Biosphere 2 from an onsite natural gas energy center through airtight penetrations.
Biosphere 2 had two closure experiments, Missions 1 and 2, during which the structure was sealed with researchers living inside. The first, with a crew of eight people, ran for two years from 1991 to 1993. Following a six month transition period during which researchers entered the facility through airlock doors and conducted research and system engineering improvements, a second closure with a crew of seven people was conducted March 1994 – September 1994. In the course of that second mission, a dispute over management of the financial aspects of the project caused the on-site management to be locked out, and the mission itself to be ended prematurely. The sealed nature of the structure allowed scientists to monitor the continually changing chemistry of the air, water and soil contained within. Health of the human crew was monitored by a medical doctor inside and an outside medical team.
In 1995, Columbia University took over management of the facility for research and as a campus until 2003. In 1996, they changed the virtually airtight, materially closed structure designed for closed system research, to a "flow-through" system, and halted closed system research. They manipulated carbon dioxide levels for global warming research, and injected desired amounts of carbon dioxide, venting as needed.
By 2006, the property, which is in exurban Tucson, was slated to be redeveloped for a planned community. As of June 5, 2007, the property including surrounding land, totaling 1,650 acres (6.7 km2), had been sold to a residential home developer for US$50 million. A development including homes and a resort hotel was planned for a portion of the land. The Biosphere itself remained open for tours.
On June 26, 2007, the University of Arizona announced it would take over research at the Biosphere 2. The announcement ended immediate fears that the famous glass vivarium would be demolished. University officials said private gifts and grants enabled them to cover research and operating costs for three years with the possibility of extending that funding for 10 years. It has in fact been extended for ten years, and is engaged in multi-year research projects including research into the terrestrial water cycle and how it relates to ecology, atmospheric science, soil geochemistry, and climate change. In June 2011, the University announced that it would assume full ownership of Biosphere 2, effective July 1.
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