One of the keys to a successful biosphere, Burgess says, is redefining the role that humans will play in their environment. ”On Earth we view all ecosystems on the basis of how they benefit humans,” he says. ”Things will be different here. The biospherians will be allowed to use a limited amount of medicinal plants and condiments. But whatever they take out (of the system)
has to be replaced with an equivalent amount of nutrients.” The nutrients will be in the form of compost.
Putting the Biosphere`s seven biomes in a line, with the rain forest highest in altitude and the others progressively lower, is intended to facilitate the movement of moisture by convection. Warm air, less dense than cold, will rise from the desert and move toward the rain forest, picking up the moisture evaporating from the ocean. When the warm moist air reaches the rain forest biome, it will be cooled by refrigerated coils, allowing the moisture to fall as misty rain or condense on the plants. The cooled air then flows down and back to the lower biomes. SBV believes the closed cycle will perpetuate itself. Although natural systems will be used as much as possible, mechanical circulation will be necessary for some wind, and electricity, perhaps solar-generated, will be used for pumping water and cooling.
One of the major problems Biosphere designers face is how to make sure it won`t be ”summer” in all of the biomes at the same time. Should all of the plants ”kick on” in unison, they would consume all available carbon dioxide and starve themselves. One solution is to use some species of plants in the desert biome that grow in the winter, when most other plants are dormant. Another way is to have a series of large metal louvers on the outside of the structure adjusting ”photoperiods” to vary the growing and dormant periods of different plants. The louvers will be operated by computers that take into account the amount and angle of sunlight falling on the structure on each day of the year.
Computer programs, like the one that runs the louvers, are integral to the Biosphere II project. ”You couldn`t have built Biosphere II 20 years ago,” says consultant Hodges. ”You had the soil and glass and almost everything else, but you didn`t have the computer capability.”
Off to the side of the wilderness biomes are the human habitat area and an intensive-agriculture settlement. The human habitat, which looks as if it might have been inspired by the Taj Mahal, contains apartments for the researchers, workshops, laboratories and a library. The people inside will be in constant contact via telephone and computer with scientists monitoring the project from the outside. When problems arise–and project sponsors expect to deal with many problems until they work the bugs out–those inside and out can work together to solve them. SBV expects scientists from all over the world, including some from the Soviet Union, to visit the site and observe portions of the experiment.
One of the goals of the project is to look at ways that humans, in their
”technosphere,” or manmade environment, can more harmoniously exist with the natural environment.
The social questions inherent in a project that puts people living closely together in a terrarium for two years are numerous. Should the biospherians be picked in terms of their personal relationships as well as their scientific abilities? Will they have to be celibate for two years? These and other questions have not been publicly addressed, and SBV officials say details of the experiment will not be available until early 1988. ”We`ll use common sense,” says Dyhr, who hopes to be one of the biospherians herself.
The Environmental Research Laboratory (ERL), headed by Biosphere consultant Hodges, is one of the project`s prime contractors. Its role is to figure out how the Biosphere will maintain human life by growing enough food but without polluting the closed environment with chemical fertilizers. A nonteaching research arm of the University of Arizona, ERL works out of a group of rather insubstantial metal buildings on a dusty, barren plot of ground near the Tucson International Airport. But that lowly appearance belies the ground-breaking research going on there.
ERL has done remarkably well with its agricultural research, and one of its successes grew out of a failed experiment. Asked to design an economical solar-powered method of removing salt from salt water, ERL researchers failed, but from their efforts came a greenhouse system that uses salt water to humidify the air. In this system plants lose much less water through transpiration and therefore take in 90 percent less water through their roots. In another big project, ERL has developed as a commercial crop a plant called a halophyte, which produces an edible oil and can be fed to livestock in meal form. Because it thrives in alkaline soil and with ocean water, it can be grown in such barren areas as the alkaline desert country of the Middle East. ERL also designed the Land Pavilion of the Disney World EPCOT Center in Florida, a 6.5-acre complex that presents a spectrum of the world`s agricultural regions and displays many ERL-developed technologies.
In considering different methods of growing food inside the Bio-
sphere, ”we`re looking at pretty much a normal American diet,” says Kevin Fitzsimmons, ERL`s bearded, youthful-looking program coordinator for the Biosphere`s agricultural section. He pauses for a moment and grins. ”Well, hopefully better than a normal American diet.”
Along with such common fruits and vegetables as tomatoes, potatoes, lettuce, grapes and berries, biospherians will grow wheat, soybeans, sorghum, squash, papayas, kiwi, rice and many different varieties of beans. Computers
–fed with complex data on balanced diets, the resistance to disease of various plants, which plants thrive well together, which serve as natural pesticides, etc.–will help them decide when, where and which crops to plant. Biospherians will also have juices and goat`s milk, chicken eggs and meat, some goat meat–and lots of fish.
The fish will be primarily the ugly but remarkable orange-and-gray creature called tilapia. Equally at home in salty and fresh water, the
hardy tilapia feeds on waste plant products and tastes good–not great, but good. In turn, ammonia-laden waste from the tilapia will be collected from their small growing vats by water-wheel-shaped filters and broken down by microorganisms in the filters into nitrates and nitrites, which, when mixed with other nutrients, can be used in hydroponics, the cultivation of plants in water filled with inorganic nutrients.
Aside from hydroponics, both SBV and ERL are researching other agricultural techniques for use in the Bio-
sphere. One of them is aeroponics, or the growing of plants in the air. In this technique, the plants–spinach, for example–are grown in rows of holes on a tent-shaped shed some 5 feet high. A patch of peat anchors each plant to its hole, green leaves outside, roots hanging freely in the air in the pitch- dark interior of the shed. Every few
minutes for several seconds a pump sprays nutrient-filled water on the roots from a shallow trough on the bottom of the structure.
One of the most prominent buildings on the SunSpace Ranch is a futuristic-looking structure that houses the plant tissue culture laboratory. Tissue culture, also called cloning, will play a pivotal role should the Biosphere get off the ground.
To clone a plant, say an orchid, a small piece is cut from a growing orchid tip. At this stage the young cells in the tip are unspecialized–anyone of them can be cultured into a complete orchid. Only later, when specialized, will some cells become the flower, others the stem, and still others the leaves, and so on. The young unspecialized cells are separated and placed in nutrient-filled water, and each will be grown into an orchid plant.
The technique is crucial to the Biosphere project in two ways. Should the Biosphere have 20 tomato plants and all of them except one or two came down with a serious disease, culturing could be done from a growing tip of a healthy plant. This is a faster process than waiting for the healthy plants to bear fruit and then planting their seeds. It is therefore ideal for the rapid regeneration of plants in space colonies on a distant planet.
The cells also take up an extremely small space, much smaller than that for grown plants and even seeds. ”Look at a vial of bull semen,” says Stephen Storm, a tissue culturist specializing in cloning endangered species who runs the tissue-culture lab at SunSpace, ”and compare that to the size of the bull. If we wanted to build a complex ecosystem (in outer space), we could never afford the freight bill (for fully grown plants). But with tissue culturing, we could store a thousand different kinds of plants in the space that one coconut seed takes up.” Furthermore, Storm says, the growing of cells in a soil-less medium avoids the possible contamination of soil by pests.
Plant diseases, in fact, pose a major potential threat to the project, especially because the plants are coming from all over the world. To meet this threat, quarantine facilities have been set up at ERL and the SunSpace Ranch to monitor all plants before they are placed in the terrarium. Soil is steamed to kill harmful bacteria. If a disease does show up on a plant in the Biosphere, affected parts are to be cut off and isolated. And should diseases or pests crop up that the biospherians can`t handle by themselves, video cameras attached to microscopes will allow scientists outside to ”look in”
and help solve the problem.
Other problems that could affect food production must also be faced. Plants, for instance, take in carbon dioxide, turn it into carbohydrates in the form of fruit and give off oxygen. ”We`re concerned that all the plants could fix all the available carbon dioxide in one day,” Fitzsimmons says.
”If the plants don`t get enough carbon dioxide, you won`t get enough productivity (to feed the Biosphere`s people and animals).” The solution is careful monitoring. During the long, warm days of June, for example, when plants do a lot of growing, the louvers can be used to shade them and thus keep them from growing too much and using up too much carbon dioxide. In an extreme lack of the gas, Hodges says, all the biospherians and the goats could be made to run 20 laps around the rain forest to produce the needed carbon dioxide.
Another concern is the natural emission by plants of methane, ethylene and carbon monoxide–toxic gases that normally pose no problem outdoors but could upset the balance of the Biosphere`s contained atmosphere. ERL`s solution is to pump the air through soil in metal boxes about the size of large refrigerators. The gases from the air percolate through the soil, where they are devoured by both introduced and naturally occurring microbes. Because these air-purification boxes, or ”soil bed reactors,” also serve as additional, space-saving planting space, Hodges sees great promise in them for spinoff technology. ”I see a day when a secretary in an office might have, not a potted plant on her desk, but a banana tree in a soil bed reactor than can filter out copying-machine fumes, cigarette smoke and other pollutants,” he says.
