By Megan Sam
That’s the question driving Taryn Chaya, a Ph.D. student in the University of Florida’s School of Natural Resources and Environment. She is investigating whether mosquito impoundments — wetlands modified to control mosquito populations — can also be managed to capture nutrients and improve water quality in coastal systems. Her work focuses on the Indian River Lagoon (IRL), once a thriving estuary on Florida’s east coast. Over time, excess nutrients from sources like leaking septic systems and stormwater runoff have fueled harmful algal blooms, leading to fish kills, seagrass loss and shellfish decline. While restoration efforts can be complex, Chaya is exploring whether part of the solution already exists on the landscape.
During the 1950s and 1960s, large areas of the lagoon’s wetlands were modified for mosquito control. Low dikes and pipes were installed to control water flow, flooding wetlands during mosquito breeding season and reconnecting them to the lagoon later in the year. Even though these wetlands have been altered, they still trap and process nutrients, with built-in inflows and outflows that allow managers to control water levels, similar to human-made wetlands designed to clean water.
“The infrastructure is there,” Chaya, whose advisor is Todd Osborne, Ph.D., a professor at UF’s Department of Soil, Water and Ecosystem Sciences, said. “These impoundments already exist. If we can better understand how they function, we may be able to manage them in ways that support water quality without major new investments.”
To study the systems, Chaya monitored several impoundments across the lagoon over two years, collecting data on water quality, nutrients and sediments to understand how water levels affect nutrient behavior. Her analysis revealed that during summer flooding, inorganic nitrogen is converted into organic forms stored in plants, algae and soils, trapping nutrients within the wetland. In winter, when impoundments are drained and reconnected to the lagoon, oxygen levels rise and inorganic nitrogen increases, which can contribute to downstream water quality problems.
“It’s very seasonal,” Chaya said. “Temperature and dissolved oxygen play a large role in controlling how nutrients behave. It’s hard to separate those seasonal changes from flooding and draining because they happen at the same time, but if impoundments are drained less often, that could prevent nutrient release. By understanding when and how these systems store or release nutrients, we can refine management to support both mosquito control and water quality.”
Chaya is continuing her analysis, including how impoundment management affects mangrove decomposition and how different parts of the wetland remove nitrogen. These insights could help optimize the nutrient-removal potential of mosquito impoundments.
“These systems haven’t been studied extensively,” she said. “But I want people to feel hopeful. With data-driven science, they could become part of the solution to water quality problems in the Indian River Lagoon and beyond.”