No toxic chemicals could be used, since they would quickly impact health.During the first year the eight inhabitants experienced hunger as they adapted.It has in fact been extended for ten years, and is engaged in multi-year research projects including research into the water use of various Arizona grass species.
They manipulated carbon dioxide levels for global warming research, and injected desired amounts of carbon dioxide, venting as needed.
On June 26, 2007, the University of Arizona announced it would take over research at the Biosphere 2.
During the second year, the crew produced over a ton more food, average caloric intake increased, and they regained some weight lost during the first year.
They consumed the same low-calorie, nutrient-dense diet which Roy Walford had extensively studied in his research on extending lifespan through diet.
The crew were: medical doctor and researcher Roy Walford, Jane Poynter, Taber Mac Callum, Mark Nelson, Sally Silverstone, Abigail Alling (a late replacement for Silke Schneider), Mark Van Thillo and Linda Leigh.
The agricultural system produced 83% of the total diet, which included a wide variety of crops including bananas, papayas, sweet potatoes, beets, peanuts, lablab and cowpea beans, rice, and wheat.During week-long periods of simulated full closure, data was gathered on agricultural operations and productivity, and crew adapted to their workload.These mini-missions were, of course, far too short to attempt any meaningful agriculture or animal husbandry.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..They recycled water including human waste, maintained a healthy atmosphere and tended a small agricultural area.These experiments were too short to attempt long-term agriculture or animal husbandry.Medical markers indicated the health of the crew during the two years was excellent.Strikingly, they showed the same improvement in health indices such as lowering of blood cholesterol, blood pressure, enhancement of immune system.At 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 above sea level at the base of the Santa Catalina Mountains.