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UT Professor Develops Model to Better Manage Toxic Algae

University of Tennessee, Knoxville Professor of Microbiology Steven Wilhelm and postdoctoral research Robbie Martin recently co-authored a publication that may change how inland waters, such as lakes, are managed. 

Cyanobacterial (or blue-green algae) blooms occur in inland waters during warmer months and are part of a normal water ecosystem. However, cyanobacteria can be harmful for both people and animals. Exposure to or ingestion of cyanobacteria can cause a number of unpleasant symptoms including fevers, muscle and joint pain, stomach cramps, skin irritation and more – in some cases the blooms can lead to death. Contaminated waterways are especially concerning for children and pets.  

“Harmful cyanobacteria are a global environmental problem, because they can produce potent toxins that endanger animals and humans,” said Wilhelm. “To date we don’t understand the factors which control the balance between toxin-producing and non-toxin producing strains, and under what conditions toxins are produced.” 

Historically, a number of approaches have been taken to reduce cyanobacteria in water, including reducing levels of phosphorous in wastewater. This phosphorous strategy was recently adopted by the U.S. and Canada in an attempt to reduce the presence of blue-green algae in the Great Lakes, particularly Lake Erie which suffers from regular algal blooms. 

However, Wilhelm and his collaborators have discovered that this strategy may backfire. The international team consisting of researchers from Technical University of Berlin, the University of Michigan, and UT developed a model to predict the behavior of cyanobacteria in response to control methods, such as the reduction of phosphorous. 

The team’s model determined that while reducing phosphorous does decrease the total number of cyanobacteria in a body of water, the remaining cyanobacteria have greater access to nitrogen. Higher concentrations of nitrogen give certain cyanobacteria the ability to produce a toxin that protects them against oxidation damage. This toxin, in turn, is highly dangerous to people and animals. The findings call for a different approach to water management that considers additional factors in the growth of cyanobacteria, like nitrogen. 

“An ability to predict when blooms become toxic is important – blooms now occur in more than 160 countries and affect large bodies of water, like Lakes Erie and Okeechobee. The paper highlights the importance of science-based decision making with state-of-the-art tools. It demonstrates the proverbial law of unintended consequences and suggests a path forward in developing management approaches that consider outcomes,” said Wilhelm.  

This work is the result of decades of research for Wilhelm and more than ten years of collaboration with the senior co-authors of the paper. The team believes their model will be useful in developing future approaches to water management. 

“No model is perfect,” said Wilhelm. “We hope that this model is a starting point to begin to integrate better science into decision making with regards to our valuable natural resources.  

This study was supported by the National Oceanic and Atmospheric Administration, the National Institute of Environmental Health Sciences, and the National Science Foundation.