For Vanderbilt researchers in the Department of Earth and Environmental Sciences, entering a cave is like stepping into a time machine that allows them to uncover thousands of years of environmental history and better understand modern climate shifts.
Led by department chair Jessica Oster, professor of earth and environmental sciences, the lab recently secured two major funding awards: a prestigious joint grant from the U.S. National Science Foundation and the Swiss National Science Foundation, and a competitive national graduate research fellowship for doctoral student Bethan Lodge.
Caves as climate time capsules
The Oster lab’s primary research focus is studying chemical clues trapped inside cave minerals. Modern weather records only go back about a century, but cave minerals preserve detailed climate history across thousands of years.
“We use caves as time capsules, specifically looking at stalagmites and using measurements of their chemistry to reconstruct the climate of the past,” Oster said. “With stalagmites, we are able to date them really precisely using radioisotopes, which unlocks potentially up to the last half million years.”
While cave formations include stalactites hanging from ceilings and stalagmites growing from floors, the Oster lab focuses primarily on stalagmites.
“A stalagmite is always going to grow from the bottom up, laying down lovely, predictable layers,” Lodge said. “With stalactites, water drips move around and can flow inside or outside hollow straws, making them much harder to date. Stalagmites provide an exceptionally clear chronological record.”
A global collaboration on wildfire research
Oster is the lead U.S. principal investigator on an international initiative called “Collaborative Research: NSF-SNSF: Fire Impacts on the Response of Terrestrial Ecosystems.”
Her project examines the formations in a cave near the Bighorn River in Wyoming, analyzing how ecosystems and plants adapt to repeat incidences of wildfires over time.
To unravel the full picture, the project incorporates specific expertise from three other institutions. Researchers at ETH Zürich, a public university in Switzerland, use radiocarbon dating to see how fire affects the global carbon cycle. A team from the University of Connecticut extracts organic molecules from cave rocks to determine what kinds of plants burned and at what temperatures, while Colgate University researchers track how wildfires affect the microscopic life in the soil and cave.
Internal Scaling Success grant at work
When the Bureau of Land Management conducted a controlled burn over the Wyoming site in 2024, Oster’s team had monitoring instruments already in place. To keep the field research alive during this crucial window, Oster applied for and received a Scaling Success internal award from the Office of the Vice Provost for Research and Innovation in early 2025.
The university funding ensured that her team could travel repeatedly to the cave to track the landscape’s rapid response to the fire and provide the foundational preliminary data needed to secure the larger federal grant.
“Without the Scaling Success funds, we would have lost that critical year right after the fire when everything’s changing really quickly,” Oster said.
That vital interim support reflects the central mission of Vanderbilt’s internal funding strategy.
“Scaling Success is designed to catalyze and accelerate the progression of ambitious research,” Vice Provost for Research and Innovation Susan Margulies said. “We celebrate Dr. Oster’s NSF-SNSF collaborative international research award, which is a perfect example of how Vanderbilt investments facilitate follow-on funding for impactful faculty research.”
Doctoral fellowship explores Utah’s past ecosystems
Lodge was recently awarded the $20,000 Charles W. Maus Graduate Research Fellowship in Karst Studies from the Cave Conservancy Foundation, which is awarded to only one graduate student nationwide each year.
Lodge’s research centers on Spanish Moss Cave, a vertical cave in the Uinta-Wasatch-Cache National Forest near Provo, Utah, where work is conducted with permission from the U.S. Forest Service. Retrieving samples from the cave requires rappelling deep underground on ropes.
By analyzing the geochemistry of cave minerals, Lodge is working to reconstruct regional climate conditions over the past 4,000 years, collaborating with paleontologists at the Natural History Museum of Utah to pair cave records with local fossil remains.
“I had done a lot of geochemistry work and really enjoyed field work, so this project was a good fit,” Lodge said. “All the caves in Utah require rappelling in on ropes, so learning those vertical caving techniques has been an exciting part of the process.”
Whether navigating vertical caves in Utah or tracking fire baselines in Wyoming, the research highlights how much modern science can learn by looking backward.
“The further back you look, the more we’re seeing climate states that we haven’t experienced before in our lifetimes,” Oster noted. “What we do really helps people take a longer view across geologic time. It gives you a good perspective on our present and our future as well.”
