Biosphere 2

Biosphere 2 is a manmade closed ecological system in Oracle, Arizona built by John Polk Allen, Space Biosphere Ventures and others. Constructed between 1987 and 1989, it was used to test if and how people could live and work in a closed biosphere, while carrying out scientific experiments. It explored the possible use of closed biospheres in space colonization, and also allowed the study and manipulation of a biosphere without harming Earth's. The name comes from the idea that it is modeled on the first biosphere, which is Earth. The funding for the $200,000,000 project came from Edward Bass.

As of June 2006, the structure is no longer airtight, and the property, which is in exurban Tucson, is slated to be redeveloped for a planned community.^*

History

Missions

The project conducted two sealed missions; the first from September 26,1991 to September 26, 1993 and the second for six months in 1994. During the first mission, oxygen levels began falling at a steady pace of 0.5% per month. This continued to the point where the atmosphere inside resembled that of a community at an elevation of over 4,000 feet (1,200 m). Eventually, oxygen levels fell to dangerously low levels, and pure oxygen was pumped in from the outside.

These issues were partly caused by low light levels- the weather that year was unusually overcast, reducing photosynthesis; while a side effect of the building construction meant that a significant fraction of the light was blocked by the structure's support beams.

Many suspected the drop in oxygen was due to microbes in the soil. The agricultural, savanna and rain forest sections had all been infused with microbes in order to encourage plant growth. In addition, the overall quantity of carbon installed in the soil at the beginning of the experiment was too high. It was now felt that these microbes were consuming too much oxygen; converting the carbon in the soil into carbon dioxide and removing the oxygen from the air.

One problem critics of this theory have cited was that microbes breathing that much oxygen would also be creating a massive amount of carbon dioxide. Yet this jump in CO₂ was undetected in the atmosphere readings. Further investigation revealed that the concrete at the base of the facility had been absorbing the carbon dioxide as it cured. This effect absorbed a large portion of the carbon dioxide being produced by the microbes which in turn had been depleting the facility's oxygen supply. Nevertheless, since oxygen and other supplies were provided, the project lost some credibility.

Difficulty of creating successful artificial biospheres

An interesting consequence of the experiment is that it showed the difficulty of copying the functions of the natural capital of the Earth biosphere with infrastructural capital constructed by humans with present technology. Despite expenditure of over $150 million, this attempt at a new biosphere did not sustain eight humans for a prolonged time.

Columbia University

In 1995 the Biosphere 2 owners transferred management to Columbia University. Since 1996, hundreds of college students have spent at least one semester at the Biosphere 2 Center campus (as of 2003). The site has its own hotel and conference center. Columbia has since divested itself of all Biosphere-related responsibilities.

For sale

On January 10, 2005 Decisions Investments Corporation, owners of Biosphere 2, announced that the Biosphere 2 campus was for sale. They preferred a research use to be found for the complex but were not excluding buyers with different intentions, such as universities, churches, resorts, spas, etc. Finally, in February, 2006, Fairfield Homes agreed to purchase Biosphere 2 and use its 1600 acres to build a planned community. ^*

Engineering

Like Project Apollo, Biosphere 2 is an achievement of engineering more than science. The above-ground physical structure of Biosphere 2 was made of steel tubing and high-performance glass and steel frames. The frame and glazing materials were designed and made to specification by a firm run by a one-time student of Buckminster Fuller, Peter Pearce (Peter Pearce & Associates). The window seals and structures had to be designed to be almost perfectly airtight, such that the air exchange would be extremely slow to avoid damage to the experimental results.

The structure was notable for how it dealt with atmospheric expansion. During the day, the heat from the sun caused the air inside to expand and during the night it cooled and contracted. To avoid having to to deal with the huge forces that maintaining a constant volume would create, the structure had large diaphrams kept in domes called "lungs". These permitted the structure to remain at ambient pressure at all times, without allowing air in or out of the habitat. Essentially this permitted the building to grow larger during the day, and shrink during the night.

Since opening a window was impossible, the structure also required huge air conditioners to control the temperature and avoid killing the plants within. For every unit of solar energy that entered the structure the air conditioners had to expend something like 3 to cool the habitat back down.

Science

A special issue of the Ecological engineering journal edited by B.D.V. Marino and Howard T. Odum (1999) represents the most comprehensive assemblage of collected papers and findings from Biosphere 2. The papers range from calibrated models that describe the system metabolism, hydrologic balance, and heat and humidity, to papers that describe rainforest, mangrove, ocean, and agronomic system development in this carbon dioxide-rich environment.

External links

Official Website
Website on biospherics and Biosphere 2
- Patent for the expanding chambers used to equalize pressure in Biosphere 2.
Book-The Human Experiment: Two Years and Twenty Minutes Inside Biosphere 2

References

BIOSPHERE 2: RESEARCH PAST AND PRESENT B.D.V. Marino and Howard T. Odum (1999)

Controlled Ecological Life Support Systems | Ecology

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