Indiana State University Newsroom

Sycamore goes back in time to help predict the future

November 2, 2016

Climate change is a little less unpredictable, thanks to recent research by an Indiana State University student.

Emily Brana, a junior earth and environmental studies major specializing in paleolimnology, used sediment samples from Devil's Lake in Wisconsin to find out the climate history of in that area by performing diatom research.

A unique type of algae, diatoms are small, single-celled organisms located in freshwater systems such as the lake in south-central Wisconsin.

"Diatoms have the ability to establish climate history with the silicon they're made of, and when they die, they drift to the bottom of a freshwater system and become fossilized," said Brana of Terre Haute. "They're good to study, because different types of diatom fossils indicate characteristics and conditions of the lake, such as temperature and plant life."

In July, Brana studied 11 slides containing diatoms from Devil's Lake to determine each type of diatom and what their existence revealed.

While conducting this research, a collection of indicators of the lake's condition were detected. Because of the information from the diatom slides, it was possible to piece together a history of the changes in Devil's Lake from hundreds of years ago.

"Our analysis indicates that there were a number of significant climate transitions in the lake region throughout the Holocene period (roughly 11,500 years ago), as glaciers receded from the landscape and the lake developed," Brana's research summary said.

The research helps scientists determine what was happening in the lake's environment before humans inhabited the area, in tandem with predicting future climates for the surrounding areas of Devil's Lake, said Brana's faculty supervisor Jeffery Stone, an assistant professor in the department of earth and environmental systems at State.

"Diatoms provide a look back in time and some context for the environment before humans arrived, as well as give us a look at the landscape in case we want to restore it or realize the impact we're having on the environment," Stone said.

Along with the diatoms, Brana studied pollen, charcoal, isotopes and metals from Devil's Lake to help make up the variables that work together to provide a more concrete prediction of climate patterns. The diatoms lived in the lake, and the other elements examined mostly represent changes in surrounding basin.

"(The indicators are) responsive to what has happened in the environment," Stone said. "Changes in diatoms indicate changes in the lake environment, and the other indicators show the climate changes outside the lake."

Even though this study has concluded, there is a possibility to do more with the data. Stone sent the preliminary results of the study to a colleague this fall in hopes of furthering research by collecting more diatom samples and looking at a higher time resolution of the climate patterns in Devil's Lake.

To have information about what the lake was like before landscape changes occurred would be beneficial to the environment to know how to preserve the organisms that live there, he said. For Brana, who plans to enter graduate school and eventually become a science professor, the experience was both rewarding and challenging.

"The hardest part was how redundant the work was at times, because I had to check over the slides numerous times to make sure they were correct," she said. "But knowing how much the samples could indicate about climate change made the experience all the more rewarding."


Contact: Jeffery Stone, assistant professor of environmental geosciences, Indiana State University, 812-237-2249 or

Writer: Kayla Carmicheal, media relations assistant, Office of Communications and Marketing, Indiana State University, 812-237-3773 or