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Biosphere Project

Biosphere Project

The physical structure

The residents

Scientific objectives

Earlier Biosphere experiments

Designing Biosphere 2



The Biosphere 2 Project was an experiment in which scientists, engineers, and some intrepid biospherians (or dwellers) within the Biosphere recreated several of the main terrains and habitats of the planet Earth and attempted to co-habit with these environments to the environments benefit. Many environmentalists see Earth as the first, original, and only known biosphere endangered by pollution, acid rain, global warming, the destruction of tropical rainforests, and a thousand other artificially produced ills. The Biosphere 2 Project was an experiment to prove that humans can live in the most precious terrains on Earth successfully and nondestructively.

The physical structure

Biosphere 2 is located in the Sonora Desert at the foot of the Santa Catalina Mountains not far from Tucson, Arizona. It is one of the most spectacular structures ever built. It is the worlds largest greenhouse, made of tubular steel and glass, covering an area of three football fields (137,416 sq ft [12,766 sq m]), and rising above the desert floor to a height of 85 ft (25.9 m). Within the structure, there is a human habitat and a farm for the biospherians to work to provide their own food. There are five other wild areas representing the savanna (extensive grasslands), a rainforest, a marsh, a desert, and the ocean. These five areas plus the Human Habitat and the farm are called biomes, which might be interpreted to mean biological homes or dwellings for life forms.

Biosphere 2 was completely sealed during the experiment so no moisture or air could flow in or out. Beyond the Biosphere, two large white domes also dominate the landscape and capture the imagination. These are balloonlike structures that operate like a pair of lungs for Biosphere 2 in maintaining air pressure inside the biosphere. Only sunlight and electricity are provided from outside.

The residents

Within the biosphere, four women and four men from three countries lived in the Human Habitat during a two-year experiment; later a six-month experiment was performed. During this time, they ran the farm and grew their own food in the company of some pigs, goats, and many chickens. They shared the other biomes with over 3,800 species of animals and plants, which are native to those habitats. It was the responsibility of the humans, scientists, and environmentalists to make sure the model of the planet in miniature survived and thrived. In 1991, the doors to Biosphere 2 were sealed for the two-year-long initial program of survival and experimentation.

Scientific objectives

The idea behind Biosphere 2 was to establish a planet in miniature where the inhabitants not only survived but learned to live cooperatively and happily together. The resident scientists observed the interactions of plants and animals, their reactions to change, and their unique methods of living. In the real world, scientists still know little about many of these relationships and how Earth achieves a balance or regains balance after some disruption. The residents also had the assignment of experimenting with new methods of cleaning air and water. Lessons learned from Biosphere 2 may help engineers to design workable living environments and life-support systems for space stations and settlements on other planets. Other biospheres may also be adaptable to less hospitable parts of the own planet. They may be used to house endangered species or environments, along with providing recreational areas of vastly different terrains near cities and, perhaps most importantly, they may be used as living classrooms to educate future generations about preservation of the original biosphere, Earth.

Earlier Biosphere experiments

Scientists have struggled for generations to understand the complex interrelationships of life forms and the atmospheric and hydrologic cycles that provide life on Earth with its essentials. Russian scientist Vladimir Vernadsky (18631943) was the first scientist to understand that the life systems of Earth are perfectly balanced and able to self-correct. Efforts to recreate these water, air, and life cycles began in 1968 when American experimenter Clair Folsome, while in Hawaii, accidentally discovered that microbes, sea-water, and algae trapped and sealed in a glass bottle did not die but created their own tiny environment in which the materials recycled naturally. Folsomes sealed bottles survived for some years, and, even after he added shrimp, the shrimp were able to live although they did not reproduce.

In Russia scientists sealed humans into small buildings to study methods of creating life-support systems in space. These experiments were known as BIOS-3, but the dwellers only had to produce half their food, and waste was disposed outside the buildings. When the Biosphere 2 Project was conceived, its creators met with Folsome, the Soviet scientists who had worked on the BIOS-3 experiments, and experts at the National Atmospheric and Space Administration (NASA) whose spacecraft and lunar module designs had allowed Americans to land on the moon.

Designing Biosphere 2

The design of the Biosphere habitats was the work of an international team of hundreds of engineers, scientists, and specialists in agriculture and diverse life species. The site in the Arizona desert was chosen because of the relative ease, in the United States, of obtaining building permits and of importing the species that would reside in the Biosphere. The project was funded by Ed Bass, a billionaire from Texas, and initiated by John Allen, a leading ecologist. The name was chosen in deference to Earth; there was no Biosphere 1 Project because the home planet of Earth is the original biosphere. The five wild zones, the human microcity, and the farm were selected to show diversity representing the planet Earth but also to improve survival of as many species as possible. Roof heights for each zone had to be selected to allow air and rain to rise and fall as it does in nature, sunlight was essential to the survival of all zones, and the habitats had to be somewhat separated so desert life would not relocate to the rainforest.

To be perfectly isolated, Biosphere 2 needed a floor separating it from the supporting ground. After the groundbreaking in 1987, construction of this sealed floor began. To support the extensive glass, steel space frames consisting of 5-ft (1.5-m) lengths of strong but lightweight tubular steel were constructed. During building, the glass panes were lifted by cranes into place. They were sealed with liquid silicone to retain interior air and moisture and to keep out the exterior. The surface of Biosphere 2 consists of 170, 000 sq ft (15, 794 sq m) of glass. Because of the purpose of the project and the huge expanse of glass, Biosphere 2 was nicknamed the Glass Ark. The domelike lungs were needed to equalize air pressure as the air inside Biosphere expands under the heat of the sun; the domes do not provide or replenish any of Biospheres air, they only provide room for heated air to evacuate.

A smaller Biosphere module was made as a proving ground. The test module was only 1/400th of the size of Biosphere. The test module was sealed to make sure it was leak-proof, and then a living test was performed using plants. A plants-only habitat was installed, along with the correct moisture and air balance, and the module was sealed for a month. Opening the door and smelling the air immediately indicated whether or not the test had succeeded; if the plants had not adjusted to this environment, they would have produced gas that smelled. The test was a success with healthy, growing plants.

In 1988, the first of three humans moved into the test module for a three-day period. John Allen had his health monitored constantly as he lived exclusively on a small tropical garden and in the fully sealed environment. The second scientist occupied the module for a five-day-long test, and the third lived in the module for three weeks. These three early experimenters were all amazed at the cause-and-effect relationships they witnessed in the module, which were much more obvious than those in the larger world.

Mechanical devices were needed to regulate the temperature and to provide rain, but the moisture supply remained constant in Biosphere 2. Soil-bed reactors were constructed to use the properties of soil and its microbes to clean the air. An artificial mountain was built to provide stream flow by gravity to add moisture to the rainforest, flow past the savanna, enter the marsh, and empty in the ocean.

The animal residents of the biomes were chosen by the captain of each biome. No large predators were allowed, and many species were rejected because their needs were greater than the scale of Biosphere 2 could support. Hummingbirds were an easy choice because they are surprisingly hardy and are excellent pollinators. Bees, bats, moths, and butterflies were also brought in as pollinators. About 40 land dwelling species included snakes, reptiles, and turtles. The resident mammals were bats and bushbabies. Of Earths thousands of species of insects, ants, termites, and cockroaches were chosen to share the habitat because they break down dead plants and animals into recyclable materials that benefit the Biosphere. Oysters and crabs were brought in to populate the replica ocean. Even a small coral reef was incorporated in the Biosphere 2 ocean. The plants were equally important and included medicinal plants, the agave, the jojoba, rubber trees, mosses, ferns, and trees that produce gums and soaps. Plants and animals that were imported into the United States were quarantined before being allowed in Biosphere 2.

The Human Habitat, or microcity, was also given special consideration to prevent the scientists from experiencing cabin fever or any feeling of being trapped. Windows look out over all other parts of the Biosphere, and each biospherian had a private apartment with an upstairs bedroom and a downstairs sitting room. The bathrooms were equipped with showers and toilets; but shower time was limited to conserve water, and toilet paper was forbidden. Drinking water was collected from moisture produced by the plants in the Biosphere. The Habitat also includes laboratory space, a medical clinic, an exercise room, recreation facilities, and a communications center. Kitchen, cooking, and cleanup duties were all shared.

The farm for the humans food consisted of eighteen separate garden plots designed to produce three crops per year. Beans, potatoes, and peanuts for protein were key elements of the farm. Oats, barley, and rice were grown; and the grains were used by the biospherians to bake bread. Fruits included pineapple, guava, apples, bananas, grapes, strawberries, oranges, and papayas; these produced not only fruit but also juice and jam. Sugar cane was grown as a sweetener. The biospherians all received special training before they were finally selected for their assignments. Physical fitness courses, training in emergencies, skin diving classes (to care for the ocean), and special training in cooking were all provided.

The pulse of Biosphere was monitored constantly by extensive instrumentation. The functions of the limited external systems were carefully controlled, and internal health including moisture, temperature, and other vitals were also monitored both by the biospherians and scientists working beyond the containment. It was up to the biospherians to adjust living conditions for all the Biospheres residents, but external monitoring provided a final check on the safety of the Biosphere population.


The eight human residents of Biosphere 2 lived inside the containment from September 26, 1991, to September 26, 1993, the longest period on record that humans have lived in an isolated confined environment. The biospherians experienced many difficulties, including an unusually cloudy year in the Arizona


Biome A geographically extensive ecosystem, usually characterized by its dominant life forms.

Biosphere Life forms that not only live together, but provide functions to maintain their environment.

Soil-bed reactor A bed of soil that, when air is passed through it, works like a filter to clean the air.

Spaceframe Steel tubes that form lightweight frames to shape and support walls, floors, and ceilings.

desert that stunted food crops, proliferation of some ant species, and unusual behavior by bees fooled by the glass walls. Another experiment was conducted for six months in 1994. Columbia University took over the operation of the facility in 1996, a visitors center was opened later in 1996, and Biosphere 2 has been maintained for study but without human inhabitants. As of 2005, the new owners of Biosphere 2, the Decisions Investments Corporation, announced that Biosphere 2 was for sale. In February 2006, Fairfield Homes purchased Biosphere 2 in order to redevelop it into a planned master community. It is unknown at this time whether the Biosphere 2 structure and facilities will be demolished or saved. As of November 2006, Biosphere 2 is currently still open daily for visitor tours.



A Living Laboratory for Earth & the Environment. New York: Columbia University Press, 2001.

Poynter, Jane. The Human Experiment: Two Years and Twenty Minutes Inside Biosphere 2. New York: Thunders Mouth Press, 2006.


Elliott, Caroline. My Holiday in a Giant Greenhouse. Focus, (February 1998): 106-109.

Stover, Dawn. Second Chance for Biosphere. Popular Science (April 1997): 56-59.


Alper, Joseph. Biosphere II: Out of Oxygen. <> (accessed November 10, 2006).

Biosphere II Center. Project Home. <> (accessed November 10, 2006).

Gillian S. Holmes

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