Capitol News

Michigan State University researchers have unveiled new insights into the complex relationship between climate change and algal blooms in U.S. lakes. The study, published in the Proceedings of the National Academy of Sciences, highlights how climate interacts with human activities like agriculture and urban runoff to influence lake ecosystems.

The research team used open-access data and satellite remote sensing to analyze chlorophyll levels, an indicator of algal biomass, across thousands of lakes over a 34-year period. This approach revealed significant climate-related patterns affecting freshwater lakes.

Patricia Soranno, a professor at MSU's College of Natural Science and co-lead author of the study, explained that "the relationship between climate change and algal biomass is more complex than expected." She emphasized the need for diverse local and regional studies to effectively manage lake ecosystems.

To address data limitations faced by previous researchers, Soranno and Patrick Hanly developed a novel method using machine learning on over three decades of satellite imagery. This resulted in a comprehensive dataset covering 24,452 U.S. lakes, combined with LAGOS-US, a geospatial research platform detailing U.S. lake features.

The findings showed that climate influenced algal biomass changes in about one-third of the studied lakes but often in unexpected ways. Only 13% experienced regime shifts; 4% saw increased productivity; while 71% underwent abrupt but temporary changes.

These abrupt changes are typically not captured by traditional methods, highlighting gaps in understanding climate impacts on water quality. The study's methods offer a way to identify these fluctuations more accurately.

Additionally, variability was found in how lakes responded to climate based on environmental conditions and human disturbance levels. Lakes with low to moderate human impacts were more responsive to climatic influences compared to those heavily affected by human activities such as nutrient input from agriculture.

Kendra Spence Cheruvelil emphasized the importance of considering both climatic and human factors when evaluating lake health: "This research provides a crucial foundation for developing effective strategies to mitigate the impacts of these stressors and protect the valuable resources that lakes provide."