UF study finds Florida’s dependence on reclaimed water making red tides worse

by | Sep 25, 2023

False color image courtesy of NASA

  • A new University of Florida study links stormwater ponds and reclaimed water to red tide algae growth.
  • Florida faces a complex challenge with over 76,000 urban stormwater ponds and extensive reclaimed water usage, contributing to persistent red tide issues.
  • The study found that the age of stormwater ponds and nutrient sources play a role, with younger ponds contributing to red tide more than older ponds.

University of Florida researchers have discovered a significant link between nutrients in stormwater ponds and the alarming growth of red tide algae blooms. The groundbreaking study, in collaboration with Mote Marine Laboratory in Sarasota, the Department of Crop Sciences at Colorado State University, and the Florida State University National High Magnetic Field Laboratory in Tallahassee, identified both stormwater ponds and reclaimed water as key nutrient sources that feed the toxic red tide algae, known as Karenia brevis.

The problem could be difficult to solve. Florida is one of the world’s largest users of reclaimed water, with over 380 systems supplying more than 900 million gallons a day of reclaimed water usage. According to the Water Reuse Association, reclaimed water is used to irrigate over 6,000 acres of edible crops, over 500 golf courses, and for more than 1,000 schools and 500,000 residences in the Sunshine State. The state is also home to over 76,000 urban stormwater ponds, which are necessary to control flooding and water flow in the state’s developed areas.

But Florida is also no stranger to red tide, a persistent environmental issue with severe consequences, including devastating marine life, causing respiratory problems in humans, killing tourism and crippling coastal economies.

The study noted that the age of the water in the ponds appears to play a role in the growth of red tide. The study found that younger stormwater ponds contributed more significantly to the growth of red tide algae than older ones. Although the reason for this is not yet fully understood, it suggests that properly aging Florida’s ponds could be a crucial factor in controlling red tide outbreaks.

Advanced techniques were in the peer-reviewed study and revealed a wide range of compounds—from amino sugars to more complex organic matter—fuel the algae’s growth. This means that both stormwater ponds and municipal wastewater can be potential nutrient sources for red tide algae blooms, underlining the need for effective water flow and retention strategies that can minimize the damage.

Ongoing research at the University of Florida aims to find ways to remove or retain nutrients from water sources, emphasizing both the urgency of the problem and the commitment to finding a solution. The study also suggests that targeted strategies could be developed to manage nutrient levels in stormwater and reclaimed water, potentially leading to future public or private sector initiatives aimed at improving water quality.

But the researchers also noted that the public shouldn’t wait for scientific or governmental solutions. Residents can significantly contribute to red tide management by reducing fertilizer use to prevent nutrient runoff and opting for native plants that require less water and fertilization. Proper disposal of chemicals and pet waste is crucial to minimize pollution. Installing rain barrels can capture and recycle stormwater, reducing the strain on treatment plants.

The study also urged the importance of science-based methods for ensuring effective water quality improvement, an effort that will likely require investment from both the public and private sectors.


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