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Danforth Center, Wash U Scientists Study Increasing Carbon Dioxide Levels On Plants

Danforth Center researcher Malia Gehan next to a growth chamber containing plants in September 2019.
Eli Chen | St. Louis Public Radio
Researchers at Washington University and the Donald Danforth Plant Science Center, including Malia Gehan, are observing the growth of plants exposed to high levels of carbon dioxide for a four-year study.

Scientists at the Donald Danforth Plant Science Center and Washington University are studying the long-term consequences of exposing plants to high levels of carbon dioxide.

Carbon dioxide levels in the Earth’s atmosphere are the highest they’ve been in 800,000 years, according to the National Oceanic and Atmospheric Administration. Scientists expect levels of the greenhouse gas to continue to rise and worsen the effects of climate change over the next several decades if people do not reduce their use of fossil fuels and other natural resources.

Some studies have shown that higher levels of carbon dioxide could change the times when plants flower or the size of leaves. But not a lot is known about how that could affect plants and their offspring, said Keith Slotkin, an associate member of the Danforth Center. 

“We’re now breaking 400 parts per million of carbon dioxide, and we don’t know how our crops are going to respond, and that’s critically important for energy, fuel, fiber,” Slotkin said. “We don’t know what we’re going to expect, and that’s what’s so exciting about this project.” 

The four-year study, funded by a $3 million National Science Foundation grant, will allow researchers to monitor the growth of six plant species, including moss, tomatoes and rice. The carbon dioxide levels inside the Danforth Center’s growth chambers will range from 400 parts per million to 800 ppm. 

The atmosphere contains nearly 415 ppm of carbon dioxide, according to NOAA. Some research suggests that levels could exceed 500 ppm in 50 years

Research has shown that higher temperatures do cause plants to grow faster, said Malia Gehan, an assistant member of the Danforth Center. However, those plants produce fewer seeds, a consequence that the study’s researchers will keep in mind during their experiments. 

“If you measure a plant’s fitness or how well it does at passing its genetic material to the next generation, that plant is less fit even though it actually grows faster,” Gehan said. 

The researchers want to avoid using the term climate change in discussing the study.

“For our particular question, we just want to look at carbon dioxide levels which we think we’re going to hit, and it doesn’t matter why that is,” Slotkin said, “but there’s also a political aspect to that as well where you take fact and you try to remove the politics from that.”

The scientists also plan to allow high schoolers to observe the study as a part of the Danforth Center’s Mutant Millets outreach program. 

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Eli is the science and environment reporter at St. Louis Public Radio.