India, Oct. 27 -- If you forget to water a houseplant for a week or two, it will droop quickly. Now imagine doing that to an entire rainforest on purpose. That is what scientists at Biosphere 2 in Arizona did in 2019. In a Science paper, Werner and colleagues describe how they turned off the rain for 9.5 weeks and watched what happened to the trees, soil, and air. The goal was to explore how a severe drought affects a forest's carbon and water dynamics.

Biosphere 2 is a University of Arizona research facility located in Oracle, Ariz. Its glass-enclosed rainforest, about the size of seven tennis courts, has 90 species of plants. It's a rare place for scientists to control the rain and watch an entire ecosystem respond. According to Univer...