Miami ecologist Lesley Knoll part of emerging field of wintertime lake research
Thousands of lakes worldwide that historically froze over every winter now experience ice-free years. Knoll is part of international team that contributed to a new review in Science on environmental and societal consequences of winter ice loss from lakes
Miami ecologist Lesley Knoll part of emerging field of wintertime lake research
Most of the world’s freshwater lakes are rapidly losing ice in response to climate change, with major implications for human safety, as well as water quality, biodiversity, and global nutrient cycles.
The rate of lake ice loss has markedly accelerated over the past 25 years and is expected to affect a substantial portion of the world’s population who rely on these lakes for diverse needs, including drinking water, fisheries, transportation, and more, according to a new review by an international team of researchers recently published in the journal Science.
Miami University ecologist Lesley Knoll, ‘01, Ph.D. ‘11, assistant professor of Biology, is a co-author of the review, Environmental and societal consequences of winter ice loss from lakes.
Knoll is among 16 researchers from 15 institutions based in the United States, Canada, and Sweden who contributed to this analysis — which represents a “major call-to-action for wintertime freshwater ecology research,” according to the lead author, Stephanie Hampton.
“Most of the world’s millions of freshwater lakes freeze, with a median ice duration of 218 days. The average duration of iced-over conditions has decreased by 31 days over the last 165 years and thousands of lakes that historically froze over every winter now experience ice-free years,” writes Hampton, deputy director for the division of Biosphere Sciences and Engineering at Carnegie Science.
“Over a billion people live near lakes that freeze, and these changes are now affecting people’s uses of lakes,” the researchers reported.
Key areas for more research
Lake scientists across the world are trying to figure out how changing winter conditions may impact lakes throughout the year, Knoll said. “Our study highlights what we know about how lake ice loss is affecting lake ecosystems and people. We also identify areas where more research is needed to enable predictions and develop management strategies.”
Several of those key areas that have major implications for human and environmental health include:
- Shorter ice duration and warmer temperatures affect biogeochemistry and microbial metabolism in lakes and put them at greater risk for water quality impairments. For example, toxic blooms of cyanobacteria can form in warmer water, putting both fish and humans at risk.
- Loss of lake ice affects the global carbon cycle. Evidence indicates that ice cover enables lakes to sequester carbon from the atmosphere and warming water releases more methane, nitrous oxide, and other greenhouse gases.
- Ice loss results in increased evaporation of lake water — which over time could decrease the surrounding community’s access to freshwater — and potentially exposes those living nearby to more intense snowfall events and greater erosion.
Wintertime lake research — an emerging field
Knoll, whose research focuses broadly on how global change affects freshwater systems, was associate director and station biologist at Itasca Biological Station and Laboratories at the University of Minnesota Twin Cities from 2015-2022. Much of her research focused on winter limnology, the study of lakes. Although scientists have been studying the ecology of Northern Hemisphere and high-elevation lakes for decades, wintertime lake research is an emerging field, according to the study authors.
“Recent advances in sensor technology allow us to more easily collect year-round data on lakes,” Knoll said. “This is beneficial because some lakes, like those in our area of Ohio, do not form thick enough ice to safely trek out on. The past two winters, my lab at Miami deployed sensors on Acton Lake to help us see how biologically active the algae are. The lake I worked on in Minnesota had ice thick enough that trucks regularly drove across an ice-road that community members kept plowed and ice houses dotted the landscape.”
Some of her new research at Miami is focused on winter limnology in Acton Lake and other nearby reservoirs. Although winters are different in southwestern Ohio than her previous location in northern Minnesota, Knoll said “we are still experiencing different winters than in the past. We do not know how this may influence lakes in the winter or into the summer.”
Long-Term Research in Environmental Biology
Knoll received her bachelor’s degree in Botany in 2001 from Miami, where she was a Regionals student for her first three years. After earning a master’s degree from Michigan State University, she received her Ph.D. from Miami in 2011, working with advisor Mike Vanni, professor of Biology who retired this past summer.
Vanni leads a team of researchers, including Knoll, that received its fifth National Science Foundation Long Term Research in Environmental Biology (NSF LTREB) grant, in support of long-term research at Acton Lake, a reservoir in Oxford, Ohio.
Awarded in July 2024, The LTREB grant provides $639,999 over the next five years for Vanni and his research team and co-principal investigators: Knoll; Maria Gonzalez, professor of Biology, Bart Grudzinski, associate professor of Geography, and Thomas Fisher, professor of Statistics.
The project has been funded continuously through the NSF LTREB program for more than 20 years.
