Plant Remains are Great Biomarkers for Clues on Ancient Climate Change

Students in Aaron Diefendorf and Krista Smilek’s “Geology through Film” spring quarter class have been learning about real science as seen through a Hollywood lens.

“We’ve watched some quality Hollywood movies, like Day After Tomorrow—which has terrible science,” says Diefendorf. “The cartoon Ice Age, on the other hand, is pretty accurate.”

The class—built for non-science majors—is fun to teach, Diefendorf says. But it also weighs heavy with importance.

“It’s critical to teach science to non-science majors because it interacts with their lives all the time. It’s important that if this is going to be the only science class they take, that we teach them the concepts that touch on their lives, like climate change, natural disasters and human impacts on the world,” he says.

Considering Diefendorf’s research interests in climate change, his urgency for science outreach and education are understandable. While earning a PhD in geology and biogeochemistry from Penn State, Diefendorf spent much of his time studying carbon isotope values of fossil plant remains from millions of years ago to better understand rising levels of carbon dioxide that caused rapid climate change.

In a study published in Proceedings of the National Academy of Sciences, Diefendorf and colleagues at Penn State found that environmental conditions and plant types have important controls on the ratio of carbon isotopes in modern leaves and by using this information, you can better constrain ancient changes in the carbon cycle.

“By looking at fossilized organic matter, we can actually use different molecules on different scales to reconstruct what plants were there in the past and how climate influences different types of plants,” Diefendorf says. “They may be from 150 million years ago, but it has some pretty powerful applications for today.”

He arrived at the University of Cincinnati in January as an assistant professor in the

Department of Geology

, but his research is only partly focused on the major Earth systems. Leaning heavily on chemistry and biology, Diefendorf hopes to create a research group in the

McMicken College of Arts and Sciences

that focuses on reconstructing past climates through biogeochemistry. He is also collaborating with other A&S faculty to obtain an isotope ratio mass spectrometer which will help Diefendorf and others study carbon isotopes.

Even though he’s been at UC a short time, he is busy teaching, applying for grants, and preparing for field work this summer in Tennessee, Florida and South Carolina.

“Right now I’m getting my lab going and finding graduate students,” Diefendorf says. “We’re already building the analytic capabilities of the geology department, which is a lot of fun. The department has been really supportive and it’s great to be in a place that has a huge commitment to doing great research.”