Florida’s Red Tides Are Getting Worse

The blooms are caused by high concentrations of a plant-like microscopic organism known as Karenia brevis fed by nutrients in runoff from stormwater, agricultural lands and wastewater treatment plants. A key stimulant is phosphorus from fertilizer used on farms and ranches in the Kissimmee River Basin, which forms the headwaters of the Everglades and drains into Lake Okeechobee, which in turn reaches the coasts through rivers and man-made canals.

The algal blooms, which at one point in 2018 covered 90 percent of the lake’s surface, can have devastating impacts on ecological resources and communities, causing respiratory and eye irritation in humans and “widespread reports of fish, sea turtle, marine mammal, and other wildlife mortalities,” according to the Florida Harmful Algal Bloom Task Force.

Released on Jan. 10, the task force’s report recommends more research to determine the causes of red tides, more investment in mitigation technologies and continued work under the Clean Waterways Act of 2020.

What the task force described as a “prolonged 2017-2019 red tide event” began with an algal bloom on Lake Okeechobee and resulted in “estimated total losses of nearly $1 billion in revenue and an additional loss of $178 million in tax revenue in 23 Gulf coast counties.”

The impacts of climate change, which the task force said “may be impossible to change,” contribute to the algal blooms “through a complex variety of mechanisms including warmer water temperatures, changes in salinity, changes in rainfall patterns… changes in coastal upwelling, and sea level rise.”