A recent study conducted by MSU researchers discovered that the landscape of Lower Geyser Basin, located in Yellowstone National Park, was altered by hydrothermal activity about 3,800 years ago to form what is the mostly treeless landscape we see today. This evidence was discovered when scientists from MSU used specialized equipment to extract a 30-foot core of mud and silt from the bottom of Goose Lake to study the area’s prehistoric climate and vegetation.
The Goose Lake study was initiated by Cathy Whitlock, Ph.D., regents emerita professor in the Department of Earth Sciences, and Christopher Schiller, the lead author of the study and a post-doctoral researcher in MSU's Paleoecology Lab. About half a dozen MSU undergraduates were also involved in doing fieldwork and lab analyses. This study was part of a much larger project led by the Woods Hole Oceanographic Institution, MSU and various other institutions.
Whitlock has been researching Yellowstone’s ancient climate for nearly 40 years, using lake sediments to reconstruct past patterns of vegetation, fire and climate change. During her years of research, Whitlock has yet to find another site within Yellowstone to exhibit a sudden reduction in forest around that time period.
“Prior to 3,800 years ago, we found abundant arsenic in Goose Lake sediments, which is mostly absent in more recent sediments,” Schiller said. “At the same time, the pollen shifts to noticeably less lodgepole pine pollen in the sediment after 3,800 years ago. This suggests to us that a major change in the Lower Geyser Basin must have caused the distribution of hydrothermal features to change and open up the landscape--creating the mostly treeless landscape we see today.”
This evidence has led the team to infer that hydrothermal activity caused this change rather than climate —which would have affected all paleoecological sites in Yellowstone.
“Yellowstone is a landscape of change. We have seen thermal areas change due to earthquakes and other processes,” Schiller said. “Our study reveals that the constant change in thermal areas has been going on for thousands of years. They will continue to frequently change into the future as well.”
The researchers are returning to Yellowstone this summer with the intent of answering two questions: “Were changes in hydrothermal activity happening throughout the Lower Geyser Basin or just at Goose Lake? What was the cause of these past changes [in] hydrothermal activity?” Schiller said. They will conduct this study by taking core samples of a group of lakes in Lower Geyser Basin to explore whether the sediments of the lakes are similarly impacted by hydrothermal activity and when such impacts occurred.
Although the future of the ever-changing geo-ecosystem of Yellowstone is unknown, there is much about the past we still have yet to discover and MSU is working on bringing more of it to light.