Biosphere 2 legacy lives on more than quarter century later

In this July 31, 2015 photo, tourists check out the Biosphere 2 Ocean, holding a million gallons of seawater, designed as an enclosed ecological system to research interactions within ecosystems, in Oracle, Ariz. University of Arizona officials say that 25 years after that New Age-style experiment in the Arizona desert, the glass-covered greenhouse thrives as a singular site for researchers from around the world studying everything from the effects of the ocean’s acidification on coral to ways of ensuring food security. (AP Photo/Ross D. Franklin)

ORACLE, Ariz. — They lived for two years and 20 minutes under the glass of a miniature Earth, complete with an ocean, rain forest, desert, grasslands and mangroves. Their air and water were recycled, and they grew the sweet potatoes, rice and other food they needed to survive.