Carolyn N. Kinder
Earth’s biosphere depends on a natural water cycle. Energy from the sun evaporates water from lakes, oceans, and other bodies of water. Water vapor builds up in the atmosphere, clouds form and become saturated, rain falls, which feeds streams and rivers that eventually return the water to lakes and oceans.
Biosphere 2 is too small to ensure the complete natural water cycle. The job of managing the water cycle was made more difficult by the demands of controlling levels of acidity and alkalinity; acidic water flowing from the rainforest would affect the neighboring Savannah, whose plant life depends on less acidic water. Fresh water also would flow into the ocean, making necessary a method for recovering fresh water again or else all the fresh water in the wilderness would eventually mix with the sea water, leaving brackish brew. A design was settled on to wed mechanical systems with natural forces, supplementing the natural evaporation from the ocean with a system to desalinate the amount of water needed to maintain the fresh water reservoir.
The closest thing to rainfall expected in the Biosphere 2 was an artificial cloud in the top of the rainforest biome generated by pumps misting nozzles, a necessity to maintain the health of rainforest species accustomed to high humidity, and the condensation on the glass and glazing that would drip. The drip and fog will modestly feed a pool atop the rainforest mountain, whose major inflow will come from water pumped out of the reservoirs in the basement. The pool feeds the rainforest stream, which meanders toward the Savannah. Before reaching the Savannah, most of the water in the rainforest stream will be diverted to pipes leading it back to the basement reservoirs, recycling it within the rainforest.
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