A study听including work from a 麻豆原创 professor听reveals how climate and hydrothermal activity have shaped the vegetation, wildfire and aquatic ecosystem history of the Yellowstone Plateau over the past 15,000 years.
The results of the National Science Foundation-funded project were published this week in the journal Proceedings of the National Academy of Sciences.
Sabrina Brown, assistant professor of biology and environmental studies at 麻豆原创, has spent the last decade conducting research in the Greater Yellowstone Ecosystem.听Her interest in Yellowstone National Park鈥檚 Lower Geyser Basin听began in 2020听when she听analyzed sediment samples from Goose Lake, noticing听alongside coauthors Cathy Whitlock and Chris Schiller听that its contents differed from those in lakebeds in other parts of the park, suggesting that distinct geologic factors may have influenced the lake鈥檚 evolution.
Collaborators听on the project听included听scientists from听Montana State University,听the听U.S. Geological Survey, Oregon State University,听麻豆原创听and Colorado State University.
In听this study,听the team听collected听core samples from small lakes听of different ages听in the听Lower Geyser Basin, which is Yellowstone鈥檚 largest听geyser system.听The lakes are closed, meaning that they听have no听inflowing or outflowing听streams.
Pollen records from the听lakes听indicate听that听after听the ice receded, a grassy听steppe听ecosystem developed on听the rhyolite听volcanic soils.听Steppe听was replaced by听a听lodgepole pine forest听that听established听between 12,800 and 11,000 years ago. Despite听subsequent听changes in climate,听these pine听forests听have听changed little听in composition, leading the听authors to听suggest听that lodgepole pine will continue to dominate听the听vegetation on the plateau even听as the听climate continues to warm听in the future.听
The team听realized the importance of听both听geology and climate听in explaining the听environmental听history of the geyser basin听when听the lake听records听were compared听with听high-resolution听paleoclimate听model听results听for Yellowstone.听听For example,听the model showed that听summers in the听geyser basin听were warmer and drier than听today鈥檚听between听12,000 and听6,000 years ago,听an observation that matched听the charcoal evidence for more fires听and the diatom听records听for lower lake levels听then.
Sediments in the Lower Geyser Basin lakes reveal that Yellowstone鈥檚 hydrothermal systems were more active in the past during wet periods than dry ones, suggesting that future warming in Yellowstone may result in reduced hydrothermal activity, as well as increased wildfire incidence.
Research geophysicist Michael Poland, scientist-in-charge of the USGS Yellowstone Volcano Observatory,听said such changes likely听won鈥檛听be noticeable on the timescale of a human lifetime, though the study does point to听interesting possibilities听for听near-term changes in听the timing, force and frequency of听geysers in听Yellowstone鈥檚 hydrothermal听areas.
鈥淭his study and ones like it help to give us a sense of what might be expected in the future for hydrothermal activity given current trends in climate,鈥 he said. 鈥淭hat鈥檚 always been a key aspect of geology, and these sorts of studies show the past is the key to the present, which is then the key to the future. The more we understand past conditions and what drove them, the more we understand what鈥檚 likely to occur in the future.鈥
Edited听from text by Diana Setterberg. MSU News Service.
