An unprecedented drought experiment at Biosphere 2 highlights nature’s surprising resilience.

Their findings, published this week in the journal Science, revealed a roughly 70% drop in the rainforest’s carbon storage — speaking to concerns surrounding forests’ ability to capture and store carbon dioxide from the atmosphere as climate change progresses. However, an intricate web of water-use strategies and soil interactions were found to support the forest’s stability in the face of extreme drought.

«The forest was, in some ways, surprisingly resilient to the drought,» said Laura Meredith, one of three leads on the project and an assistant professor in the School of Natural Resources and the Environment in the College of Agriculture and Life Sciences.

The glass-enclosed rainforest at Biosphere 2, which houses 90 plant species across an area the size of seven tennis courts, allowed the researchers to simulate a full ecosystem drought.

The experiment, called Water, Atmosphere and Life Dynamics — or WALD, which is German for «forest» — set out to capture every bit of data possible throughout the drought and rewet process. Nearly 2 miles of Teflon tubing and more than 133 sensors were placed throughout the roughly 3-acre rainforest to simultaneously collect measurements on everything from carbon pools in the atmosphere and vegetation, to microbiome and deep-water soil processes.

«We used stable isotopes to trace the movement of carbon and water through the ecosystem under normal conditions and severe drought, which revealed surprising plant-ecosystem interactions,» Meredith said. «Importantly, individual plants did not all respond to drought in the same way. Some were highly drought sensitive and quickly slowed their critical carbon and water cycling to play it safe, while others were more tolerant of drought and maintained their function even under more risky drought conditions.»

In their experiment, the researchers categorized the plants’ reactions by their drought-tolerance and drought-sensitivity in both large canopy trees and undergrowth species.

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Materials provided by University of Arizona. Original written by Rosemary Brandt. Note: Content may be edited for style and length.