On our winter stay in Arizona, we took a day trip from Benson to tour Biosphere 2 in the Santa Catalina Mountains at Oracle, north of Tucson. We arrived in time for an 11:00 “Tour Under the Glass,” which describes the narrated walk-through of the glass dome structure covering 3.14 acres. The tour is approximately an hour and a half walking one way; we did not return to any biome. A caution for those who have health or mobility issues: the tour includes steps.

Originally built between 1987 and 1991 as an artificial, materially-closed ecological system designed to study how the earth’s natural systems work, Biosphere 2, named because our planet earth is considered Biosphere 1, was inhabited by eight individuals from September 26, 1991 to September 26, 1993. Although some touted the closed mission as the most exciting scientific project in the United States since our astronauts launched for the moon, critics called the experiment a complete failure.

Our guide on the tour admitted that despite the original mission crew’s extensive training aboard a ship and in the Australian outback, they encountered unexpected challenges. The concept behind the mission was to explore the complex life systems in an isolated structure that included five areas or biomes: ocean, tropical rain forest, savannah, marsh and desert. The eight people lived in an agricultural and human living/working space the size of three football fields. They studied the interactions between humans, farming, and technology with the rest of nature. They also explored the possible use of closed biospheres totally isolated from the outside world with the idea that Americans might one day colonize Mars. The group included a doctor and a doctor’s assistant who could do some minor dental work, and people trained in mechanics and different areas of science. Yet, they had to start from scratch to grow their food and in the first year, everyone became stressed by the low calorie diet. The amount of physical work required did not match their dense caloric intake. Also, during those first months, oxygen levels inside the bubble dropped, causing further physical and mental challenges. Going into the program, the team members were close friends and contemporaries. Still, friction erupted. Our guide said, “They were brilliant people and had different ideas about how to do things. We’ve heard that at times people wanted to leave, but no one would be the first. So they all stuck it out for two years.”

On July 1, 2011, the University of Arizona assumed full ownership of Biosphere 2, accepting the land and buildings as a donation from a former owner, CDO Ranching & Development. The Philecology Foundation (a nonprofit research foundation founded by Ed Bass) pledged $20 million for the ongoing science and operations. Researchers are now involved in the largest experiment ever in environmental science, using this huge facility as a sophisticated controlled instrument that allows scientists to measure and manage every factor in the five ecosystems. Because of its enormous size, Biosphere 2 can support these systems on a close to real scale. Each of the communities is planned and measured by the soil, temperature, and absence or presence of water. In fact, water is the main focus of Biosphere 2 research. Mr. and Mrs. John Q. Public and their families have the privilege of peeking into these research projects on the daily tours.

Our tour began in the orchard where the biospherians grew and gathered fruit for their diet. From there, we moved on to the 20,000 square-foot rain forest modeled after one in the Amazon Basin or a Costa Rica mountainside. Plants of manageable size were initially brought in from different countries in Central and South America. In 2012, we looked at 20 years of growth and adaptation, a jungle-like environment with waterfalls and an earthy smell. The biome is 90 to 92 feet in height, so plants that grow only to 85 feet were chosen. The rain forest, as all other biomes, is computer controlled, so scientists can create wind, fog, or rain—or withhold those elements.

Our guide often reminded us that when the biospherians lived there, everything was open from one biome to the other. Today, walkways, platforms, and even plastic barriers are in place so visitors can view the different areas under the glass dome. All the time that visitors are looking and learning, sensors in the soil or cameras high above the trees document and measure all moisture and trace gases and how they affect the plants. A bamboo belt across the front of the rain forest protects its trees from saltwater spray of the man made ocean.

The ocean may not be the picturesque image in our mind because it is a laboratory tool. However, this man made ocean is the only place in the world where scientists can study coral reefs in a completely controlled environment. Our guide told us that the ocean in Biosphere 2 holds 676,000 gallons of Pacific saltwater. The first 100,000 gallons were actually transported from the Pacific Ocean to the Arizona desert on milk trucks. The remaining gallons came from wells on the property and mixed with the right amount of salinity to create a Pacific saltwater ocean with tropical fish. A vacuum tube at the far right end of the ocean creates a gentle wave lapping on shoreline to mix oxygen and food throughout the saltwater. The fish survive on whatever food they get from the 25-foot deep ocean. Researchers at Biosphere 2 study the ocean waters and different aspects, such as ocean viruses. Following the narrated tour, we were on our own to go to the lower level and view the bottom of the ocean through windows. The water had a yellow haze, which signs informed us was algae, not dirty water. Numerous species of tropical fish swim past the windows.

On our walking tour, we stood before a savannah, principally grass and an acacia tree patterned from a savannah typically found in Australia. Inside Biosphere 2, the acacia is not subjected to a large volume of wind and does not develop the thick bark that helps it to stand upright. Ropes fastened to the ceiling looped around the tree’s limbs to hold up the sagging branches.

Next, we walked along a platform and down steps to the mangrove marsh. While the rain forest is called the lungs of the earth, the marsh is called the kidneys of the ocean. All the plants and soil in that biome came from the Florida Everglades. The other biomes are a mixture of Arizona soil and plants from around the world. The mangrove marsh becomes a salt-water marsh as it gets closer to the ocean. The dense system of roots harbors small animals and some fish. In the outside world, that kind of marsh would also be home to small birds, but no birds reside inside Biosphere 2. Insects, lizards, frogs, and possibly a few snakes inhabit the biomes under the glass bubble.

The desert biome is a desert fog area, typical of land found along a coast line near the ocean, such as the Baja Peninsula in California. The desert biome of Biosphere 2 has a high level of moisture and humidity. The typical cactus is a cardone, often called an elephant cactus because with age, it turns gray and wrinkled like an elephant’s trunk.  Cave-like structures in the desert are connected to air shafts that control the amount of wind.  On the last portion of the tour in the lower level of Biosphere 2, we walked in front of the huge air handlers and felt their power.

Gray pipes running along the glass at the top of the dome are attached to the facility’s large water storage tanks downstairs. When researchers do different projects in certain areas, they control the rainfall that comes through those pipes. When the biospherians lived inside the dome, the desert area produced a large part of the oxygen under the glass, especially in the wintertime. Above it, a thorn scrub area, active in summertime, provided oxygen for those months.

We exited the glass dome through the lower level, listening to our guide’s explanation of all the mechanical elements—air handlers, pipes, valves, pumps, and coils—that make Biosphere 2 operate. During the first closed mission in which the eight people lived inside the glass bubble, they had to maintain all the equipment. Biosphere 2 is encased in steel and concrete and during the closed mission there was less than a ten percent exchange of air to the outside world. Our guide said that at the time of its construction, Biosphere 2 was considered an engineering marvel.

On our own, we returned to Door 7 of the Biosphere 2 complex and toured accommodations of the biospherians during their two-year stay on the patch of earth under glass. We viewed one of the two-story apartments occupied by an individual. The lower room, which we could see through a window, appeared to be an art studio. But signage stated that each biospherian decorated to his or her taste. Some lined the walls with books on shelves. A spiral steel staircase climbed to a bedroom above. The crew shared a central kitchen with every modern convenience and a large dining area. Each person cooked every eight days, starting with dinner, and then preparing the next day’s breakfast and lunch. Some animals—chickens, goats, and pigs—went into Biosphere 2 with them, but they had to do their own butchering and processing of meat. Although each participant completed the mission fit and healthy, their 2200 calorie daily diet, mainly vegetarian, had been an adjustment.

Biospherians no longer inhabit Biosphere 2. Their quarters and common areas are silent; the kitchen’s gleaming black and white appointments show no trace that two year’s of daily meals were prepared there. The closed mission—at least from one participant’s perspective—is recounted in Jane Poynter’s book: The Human Experiment: Two Years and Twenty Minutes Inside Biosphere 2. The controversy about what those eight people accomplished continues, but the bottom line is what is left: an enormous scientific tool that allows scientists to study and manipulate aspects of Earth without causing harm to our fragile planet. Under the ownership and management of the University of Arizona, water is the main focus of research under the glass. A spokesman for Biosphere 2 says:  “Water stitches the physical and biological world together. If we better understand water, then we have a tool to go after the global changes and to make predictions about their impacts.” And while scientists learn, we citizens have the opportunity to observe, and perhaps, also learn how to better care for Biosphere 1.