A new study led by Michigan State University researchers utilizes satellite data and machine learning to explore how climate change and human activities impact algal blooms in 24,000 U.S. lakes, providing vital insights for environmental management.
A recent study led by researchers at Michigan State University (MSU) offers new insights into the intricate relationship between climate change and algal blooms in 24,000 freshwater lakes across the United States.
Using open-access data and novel analytical methods, the study elucidates how climate interacts with human activities to affect these critical ecosystems.
Complex Interactions Unveiled
Each summer, lake beaches are increasingly closed due to the menace of toxic algal blooms.
While climate change is often perceived as the primary culprit, this study reveals a more nuanced scenario where climate and human activities, such as agriculture and urban runoff, collectively influence the proliferation of these blooms.
“Our research demonstrates that the relationship between climate change and algal biomass is more complex than previously understood,” co-lead author Patricia Soranno, a professor in the MSU College of Natural Science, said in a news release. “While climate change is a significant driver in algal biomass, we found that the impacts are not always gradual or predictable. To effectively manage and protect lakes, we need to study these effects in many different local and regional contexts.”
Innovative Methods
The MSU team, led by Soranno and Patrick Hanly, a quantitative ecologist in the MSU College of Agriculture and Natural Resources, utilized over three decades of publicly available satellite imagery alongside machine learning techniques.
This approach generated an unprecedented dataset that tracks chlorophyll levels — a key indicator of algal biomass — in 24,452 lakes across the United States.
The comprehensive dataset was paired with LAGOS-US, a geospatial research platform detailing lake features in the United States. This integration allowed the researchers to uncover climate-related patterns in algal biomass and probe their changes over time.
Significant Findings
The study, published in the Proceedings of the National Academy of Sciences, disclosed that climate-driven changes in algal biomass were evident in 34% of the lakes studied.
However, the responses were diverse: only 13% of affected lakes experienced long-lasting regime shifts, 4% showed increased productivity and 71% exhibited abrupt but temporary changes.
Although these temporary changes can seem reassuring, the annual fluctuations they represent have historically been understudied, leading to gaps in understanding climate’s impact on water quality.
Variability and Human Impact
This large-scale analysis also highlighted how variation in climate responses depends on environmental conditions and the extent of human disturbances.
Lakes with low to moderate human impact showed higher climate responsiveness, while those already heavily impacted by activities like agriculture were less directly influenced by climate.
“Our findings emphasize the importance of considering both climate and other measures of human impacts when assessing the health of lakes, especially over decades,” added co-author Spence Cheruveli, the dean of MSU’s Lyman Briggs College. “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.”
Broader Implications
MSU’s findings hold significant implications for environmental management practices. By demonstrating the complex interactions between climate and human activities, this study underscores the necessity for holistic approaches to manage and preserve freshwater lakes amidst climate change.