Forest scents help UA researchers solve climate change mysteries at Biosphere 2

Smells of the forest help Biosphere 2 scientists understand stresses of climate change
Smells of the forest help Biosphere 2 scientists understand stresses of climate change(KOLD)
Published: Nov. 21, 2022 at 6:54 PM MST
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TUCSON, Ariz. (KOLD News 13) -Forests are Earth’s natural air purifier, but climate change is messing with this important tool for cleaning up our air.

University of Arizona researchers at Biosphere 2 think the solution may have something to do with how plants smell.

Dr. Joost van Haren has been studying how and why plants make compounds that create certain scents. He found they shift with conditions. Consider the smell of desert rain.

“Here in Arizona for instance, when it rains, you immediately smell Creosote - that is a chemical released by the plants in response to the rainfall,” van Haren said.

By forcing B2′s 30-acre “rainforest under glass” into an artificial drought for three months, the team could see - and smell - the effects of climate stress.

“What we found, during this drought, it shifts in time, when they’re producing these compounds and how much of these compounds they produce, as well as the kinds of compounds they produce” van Haren said.

The plants can even use the compounds to warn each other about predators, like insects. But most of these compounds can’t be detected with the human nose because they don’t build up enough in Earth’s atmosphere. So, Biosphere 2 laced tubing and sensors to collect data and measure reactions along the forest floor using hyper-sensitive devices.

This Southern Arizona rainforest is the perfect place to watch the response to this fabricated stress.

“You can control how much air is in here, how much water, what is the variable. You have control over whatever variables you want to test,” said Miranda Quiroz, a B2 tech and UA Environmental Science major.

All plants clean the air by taking in carbon dioxide and releasing oxygen. But, what if they can’t?

“If the leaves cannot fix any carbon any more because they are too stressed, they close their pores,” van Haren said. “That would be a problem, especially because these plants use some of these compounds the plants make actually help the plants to seed clouds.”

When an ecosystem is in drought, plants may use these compounds to drive the formation of clouds - and rain. If the healthy cycle breaks, a vicious one begins.

“One-third of rain in a rainforest, like in the tropical basin, is actually recycled water from the trees,” said von Haren, “If it needs to produce more of these compounds because it’s under stress or wants to seed its own clouds, then there’s less carbon left over for growth, which is the carbon that’s stored in its trunk.”

That’s bad news for humans. The carbon can stay in the trunk for hundreds of thousands of years, protecting our air. The team is also tracing the carbon dioxide to see how trees use it.

“When you cut the trees, they can’t put water back up into the atmosphere, which is still happening in the amazon basin this could become a runaway effect potentially,” said von Haren.

So, how do we keep this natural cleaning crew - and scents that come with them - flowing and healthy? The answer - may be under the dome.