by Adam Hinterthuer
In 1985, a landmark paper in the journal, BioScience helped broaden horizons in the field of aquatic ecology and led to a series of whole-lake experiments conducted by Center for Limnology (CFL) researchers on lakes within the University of Notre Dame’s Environmental Research Center (UNDERC) along the borders of northern Wisconsin and Michigan’s Upper Peninsula. Not only did the paper explore concepts like top-down impacts on aquatic food webs and the idea of managing lakes by manipulating fish populations, it also launched an ambitious research collaboration that continues to this day.
Named “Cascade” the project set out to use the unique opportunity afforded by UNDERC lakes to conduct a series of long-term, whole-lake experiments to answer questions about things like food web structure, the impacts of excess nutrients and how our lakes are changing over time. The goal was to produce actionable science – research that could lead to new knowledge and methods for resource managers tasked with conserving our invaluable freshwaters.
CFL director emeritus Steve Carpenter, a founder of the project and lead author of the BioScience study, remembers the excitement behind the work they were doing. “Ecosystem experiments are a sure-fire path to novel and interesting results,” he says and the ability to use lakes at UNDERC, especially the ecologically famous Peter and Paul Lakes, enabled the team of researchers to test all sorts of hypotheses. Carpenter likes to compare the ecological sciences to a “four-legged table” held up by whole-lake experiments, long-term data, cross-landscape comparisons and modeling. Cascade gave limnolgists rare access to the whole-lake experiment part of that equation.
This summer, CFL graduate student Danny Syzdlowski continued the Cascade legacy by, well, dyeing a lake blue. Algae blooms are caused by a complex combination of factors, Syzdlowski explains, which is why he helped devise a whole-lake manipulation using a non-toxic dye called Aquashade. “Algae need light to grow, so we wanted to see if by blocking out that light we could change the resilience of the lake and make it harder for algae blooms to happen,” he says.
Unfortunately, Syzdlowski and his summer undergraduate field technician encountered an unusually stormy summer this year and their dye additions kept getting flushed out by rains. The good news, though, is that, just like every summer since 1985, researchers will be back out at the Cascade lakes next field season and can “try again to get more definitive results,” he says.
The ability to keep long-term research projects going through different challenges is a key component of the Cascade project, says associate professor Grace Wilkinson. Work like Syzdlowski’s may someday provide critical insight into making informed decisions about how to best take care of our fresh waters. “The combination of accelerating climate change interacting with changes in land use, land cover, and [fishing] harvest by humans is leading to a higher chance of abrupt ecological change,” Wilkinson says. And those changes can have “profound” consequences for both human and environmental well-being. “Our current experiment is an effort to move ‘resilience’ as a concept out of our textbooks and into the toolbox for policy and management,” she says.
Wilkinson is now the lead researcher on the Cascade project and says she’s looking forward to leading it into the future. “I’m excited to carry on the legacy of whole-lake experiments in Peter and Paul Lakes,” she says, adding that she hopes the project grows to involve new collaborations that will help researchers “tackle pressing questions about the response and management of lakes in an era of unprecedented global change.”