- UA Green 
The University of Arizona's Biosphere 2, built as a sealed research platform to determine if human life could be sustained for long periods on distant planets, has become a center for the study of sustainability here on Earth.
The Biosphere 2 facility was built in the 1980s to research and develop self-sustaining space colonization technology. Two missions in the early 1990s saw teams of researchers called Biospherians sealed inside the enclosure to determine if they could survive in a limited environment similar to what might some day be built on another planet.
The visually striking 3.14 acre domed facility featuring 6,500 sealed glass windows – which has been managed by the UA since June 2007 – now offers a unique test bed for research closer to home, said Nate Allen, Biosphere 2 sustainability coordinator.
While other scientific disciplines boast huge research facilities and tools, like supercolliders for physics and enormous telescopes for space exploration, life sciences, and especially ecology, lacked such a major research facility until Biosphere 2, Allen said.
"Biosphere 2 was the largest attempt ever to create a natural environment, or as close to it as you can," he said. "Now we primarily use Biosphere 2 as a place where we can not just observe natural phenomena, but where we can try to control it in order to learn more about what the mechanisms of environmental change are. So it's really an apparatus for exploring ecological questions of scale, of interrelationships, and of change.
"Almost everybody who knows anything about Biosphere 2 knows about the rainforest and the ocean and the other biomes that we have inside. They are not really environments but they are pretty close to that and they allow us to learn things about the real environments because we control and manipulate those things," Allen said. "So this concept of what we can use Biosphere 2 for, to model, in very many different ways, has become the central theme for the University of Arizona for doing research here at the Biosphere 2."
While Biosphere 2 offers researchers a unique opportunity to undertake controlled studies in a closed environment that would be impossible to find in nature, scientists combine their indoor work with what is going on outside the facility, said John Adams, assistant director of planning and facilities.
"A lot of the researchers not only are doing research inside Biosphere 2, but they also have research sites exterior to Biosphere 2," Adams said. "We're not only doing experiments here, we've also got researchers who have watersheds and they've got them instrumented in very similar fashion in the Catalina and the Santa Rita mountains. Biosphere 2 is one tool that can be used to better understand these processes but it is critical we integrate that with what is going on outside."
Adams is working on the UA's Landscape Evolution Observatory, a project to build the largest artificial watershed ever seen. The effort so far has seen the soil removed from Biosphere's half-acre former agricultural area where Biospherians grew their food.
Three huge soil-covered watersheds set at 10-degree slopes will be constructed beginning this summer that will allow researchers to closely and under controlled conditions study how "rain" water moves through and interacts with soil and eventually vegetation, he said. Each slope, when covered with about three feet of black cinder soil sourced from the northern Arizona, will weigh about 10 million pounds.
"The fundamental question is how does water, when it rains in the mountains, end up in the river," he said. "How is it partitioned as it moves through the landscape, how does it that partitioning change as you have land use changes, an are there tools and mechanisms by which we can better predict this potential behavior as we see some of these changes happen?"
Researchers are currently testing sprinkler systems to find the best way to provide the test bed with a uniform level of precipitation, he said.
Biosphere 2 also offers a chance for the public to get up close and personal when learning about sustainability research, Allen said.
"One of the prime goals of the University of Arizona here at Biosphere 2 is that it's a facility that offers a unique opportunity for the public to directly interrelate with scientists," he said as a tour of about 20 high school students passed by. "Visitors can ask scientists questions, like why should we care about this, is climate change real and how do we know that? All of those kinds of opportunities to directly interact with scientists area pretty unique."