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Biosphere 2: Morningglories contribute to failure of ecosystem
by Bob Hartzler

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11/20/96 -- Biosphere 2, a 3.15-acre closed ecosystem in Oracle, Arizona, containing soil, air, water, plants, and animals was designed to allow eight humans to survive for two years without contact with the external environment. However, many problems quickly arose in the ecosystem, therefore cutting the scientists stay short. Among the problems facing the scientists was a runaway weed problem. Morningglories (Ipomoea hederacea) were established in Biosphere 2 to act as a carbon dioxide sink. However, problems with construction of the structure resulted in disruption of the O2/CO2 balance. The morningglories were exceptionally aggressive in the CO2 depleted atmosphere, therefore allowing them to overtake the crop plants. "The weeds required a great deal of hand weeding, which was not entirely successful."

This is yet another example of weeds adapting to a niche created by man's activities, which occurs continually in agriculture.

Source: Biosphere 2 and Biodiversity--The Lessons So Far. SCIENCE 15 Nov 1996; 274 (5290):1150. Joel E. Cohen and David Tilman.  

Prepared by Bob Hartzler, extension weed management specialist, Department of Agronomy, Iowa State University

For more information contact:
ISU Extension Agronomy
2104 Agronomy Hall
Ames, Iowa 50011-1010
Voice: (515) 294-1923
Fax: (515) 294-9985
http://www.weeds.iastate.edu
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