Bloom Watch: Forecasting Trouble in Lake Okeechobee with New Model

July 28, 2025

By Dr. Paul Julian, Biogeochemist and Lead Study Author

Algae bloom in Lake Okeechobee. Photo by The Everglades Foundation.

Every summer, algae blooms erupt across Florida’s largest lake, choking the ecosystem, threatening public health, and complicating Everglades restoration efforts. But what if we could predict these outbreaks before they begin? A new peer-reviewed study from The Everglades Foundation and the National Park Service is doing just that. Using cutting-edge modeling and decades of water quality data, researchers have created a powerful tool that helps explain where and when blooms are likely to occur. Using this predictive tool, this study explores how smarter water management can help reduce bloom severity. 

At the heart of the study is a custom-built model that links lake levels and nutrient patterns with bloom behavior across five key zones of Lake Okeechobee. The findings offer a science-based roadmap for restoration planners, showing how decisions about water storage and infrastructure can reduce harmful algae—and protect the health of the entire Everglades ecosystem. 

Improving Forecasts for Harmful Algae Blooms

Port Mayaca Lock and Dam in Lake Okeechobee. Photo by the USACE.

Algae blooms are a persistent seasonal occurrence in Lake Okeechobee. Driven by high nutrient concentrations, harmful algae like Microcystis, a toxin-producing blue-green algae, bloom during the warm summer months. Harmful algae blooms pose a significant challenge to ecosystem health and downstream restoration efforts in the Everglades. A new study published in Frontiers in Water, led by Foundation scientists in collaboration with the National Park Service, took a data-driven, science-based approach to predicting algae blooms using advanced modeling techniques.  

In this study, we re-evaluated prior modeling efforts that used lake stage (i.e. water level) to evaluate bloom risk across the lake. Generally, higher water levels increase the likelihood or chance of algae bloom development. However, this model was limited in its ability to predict blooms across the lake. Therefore, a second model was developed to account for variation in algae bloom driver across the Lake.  

The second model, the Lake Okeechobee Hydrodynamic and Biogeochemical Chlorophyll Hierarchical Additive Zonal Model (LOK HABAM), uses decades of water quality and hydrologic data to predict summer chlorophyll-a concentrations, a key indicator of algae blooms. Specifically, the model predicts chlorophyll-a concentrations across five distinct ecological zones using a combination of water quality and hydrologic variables.  

Animation of predicted monthly Chlorophyll-a concentration across Lake Okeechobee from 2008 to 2025. Top plot it the time series (red solid line is monthly median concentration, dashed lines are 95th and 5th percentile concentrations).

These models were applied to restoration and operational planning efforts, such as the Lake Okeechobee System Operating Manual (LOSOM) and the Lake Okeechobee Component A Reservoir (LOCAR). The goal was to evaluate how operations and restoration infrastructure can influence algal blooms in the lake. The model demonstrates how restoration strategies, such as adjusting lake stages or modifying infrastructure, can help significantly reduce bloom risk. 

Why this matters for Everglades restoration 

Commonly called the beating heart of the Everglades, Lake Okeechobee is a major headwater to the Everglades ecosystem. The lake provides not only water to the Everglades but also supplies domestic and agricultural water supply, is an essential component to regional flood protection, and has a unique ecology that makes it popular for recreational activities (i.e. boating, fishing, hunting). While algal blooms on the lake are a tell-tale manifestation of other issues (i.e., poor lake water quality) it can also impact downstream waters by affecting water quality.  

The model provides a powerful tool for informing water management decisions, optimizing restoration infrastructure, and tracking ecological responses to management actions. Understanding how lake levels and nutrients drive algal blooms is key to turning the tide. This work showcases interdisciplinary, applied science with direct implications for ecosystem restoration and water policy, delivering data-driven tools for real-world decision-making.

St. Lucie River in Florida. Photo by Robert Miller, Adobe Stock.

Read the full Frontiers in Water article here: https://www.frontiersin.org/journals/water/articles/10.3389/frwa.2025.1619838/full

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