RAPID: Coastal consequences of engineered water control systems: the role of freshwater discharges in Florida's ongoing harmful algal bloom crises

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Several hundred tons of marine life have died along the Gulf shores of Florida since October 2017 from exposure to algal blooms known as a "red tide". The intensity of these blooms is believed to be related to nutrients in freshwater releases from Lake Okeechobee, a large inland lake in south-central Florida that is managed for flood prevention. However, strong scientific evidence to support the connection between the red tide and Lake Okeechobee water releases is lacking. The objective of this project is to collect, analyze, and model water quality data prior to and throughout major freshwater releases. These data will provide insight into cause-and-effect relationships between freshwater releases, and algal blooms. Findings from this study will directly inform management of one of the nation's most elaborate freshwater flood prevention systems, and support efforts to address the ecological emergency caused by red tide. The central goals of the proposed work are to define the effects of human-managed freshwater control regimes on the magnitude and duration of coastal algal blooms, and transfer knowledge gained from this study to the public and decision-makers through education and outreach activities. We will investigate connections between Lake Okeechobee releases and coastal algal blooms of the species Karenia brevis using an interdisciplinary, data-intensive, multi-scale, and integrated fresh-marine systems approach. This effort necessitates rapid mobilization to collect targeted data on nutrient and algal loads along the Caloosahatchee River and Estuary that connects to Lake Okeechobee via canals. The project has the following objectives: (1) quantify spatial variability in water column conditions (water chemistry and phytoplankton community) across 13 sites from a fresh-marine gradient in southwest Florida prior to, during, and after Lake Okeechobee discharges, and (2) explain spatiotemporal variability in water column conditions as a function of physical, chemical, and biological factors. The combination of an ongoing red tide and imminent freshwater discharges from Lake Okeechobee creates a unique setting for investigating causal relationships between freshwater discharges and coastal algal blooms. To our knowledge, this study will be the first to couple multi-scale observations (i.e., in situ point observations, continuous monitoring data, and satellite imagery products) to analyze connections between freshwater discharges and marine red tides.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.