India, Oct. 27 -- Every three months, an ocean in the Arizona desert took a trip through time. In 1996, Columbia University researchers used Biosphere 2's marine mesocosm to recreate three sets of ocean conditions: those of a glacial ice age, the present day, and the 22nd century. According to the University of Arizona's Biosphere 2 ecosystems page, the researchers alternated between these conditions at three-month intervals over three years. The experiment examined how changing carbon dioxide levels and seawater chemistry affected photosynthesis and coral calcification.

The tank behind the experiment is no ordinary aquarium. Originally designed to simulate a Caribbean coral reef, the enclosed ocean system has a surface area of 35 by 20 ...