Visitors and locals alike in South Florida are getting an up-close experience with a deadly beach condition. Harmful algal blooms (HABs, also referred to as “red tides”) occur when warm water is fed by nutrient overload. Toxic microorganisms feed on the nutrients like phosphorus and bloom in vast quantities, distributing their poison as they go. They can cause respiratory, skin, and neurological problems in animals of all sorts, including humans. In southeast Florida, 15 people have been sent to the ER with symptoms related to the super bloom. While HABs are a natural process that happens in the warm months of summer, humans contribute to these more frequent and intense blooms.
This 10-month long HAB is the longest and largest continued algal bloom since 2006. It’s reached as far north as Tampa Bay and as far south as Key West. Blooms can vary in color depending on the species responsible. This HAB appears green due to the blue-green bacteria. This and other events have occurred following the release of nutrient-loaded water from Lake Okeechobee, one of the top 10 largest freshwater lakes in the United States. Human’s relationship with the land has drastically changed the Lake and Florida itself.
Over 100 years ago, Lake Okeechobee historically drained south, feeding the Everglades and over 10 watersheds in southern Florida with clean fresh water. As more people moved to Florida, the Army Corp of Engineers and the South Florida Water Management District built a dike to hold in the water and dry up 400,000 acres of wetlands. Sugar Cane fields surrounded the lake and the agricultural powerhouses that own them are collectively known as “Big Sugar.”
The nitrogen and phosphorus that are distributed in the Big Sugar fields to encourage fast growth run off into the Lake. Over time, the nutrients build up to intense concentrations and provide the perfect blooming ground for the microorganisms that cause HABs. As the Lake fills, this nutrient and algae-loaded water is diverted west to the Caloosahatchee River and east to the Saint Lucie River. Fish kills and damages to human health start at 10,000 algal cells per liter. The current bloom carried by the Caloosahatchee to the Southwest coast is well above one million cells per liter.
Agencies and businesses in affected cities are responding as quickly and efficiently as they can to manage local impacts of this HAB. Beaches are declared hazardous until the bloom clears, a financial blow to the local tourism businesses. The City of Sanibel has hired additional workers to remove dead animals from the beach, including sea turtles, manatees, and a whale shark. Waterfront property owners are now allowed to collect and dispose of fish near their land, something that usually requires a fishing license. Wildlife rehabilitators up and down the Southwest coast are busy treating animals with neurological and muscular issues that are symptoms of HAB exposure. The Sanibel-Captiva Conservation Fund that responds to 30-35 sick or injured turtles per year saw 53 in June and July alone.
Aside from the altering of Florida’s natural flow, one of the biggest problems is the lack of vegetation along the Rivers. Plants act as a natural filter and remove the nutrients that cause HABs. They also slow down the water, making it even easier to suck up all the extra nitrogen and phosphorus. A satellite scan by NOAA revealed that 30% of Lake Okeechobee’s open water contains an algal bloom, while the marsh areas with vegetation had little to no bloom present. Creating man-made filtration methods in Lake Okeechobee’s drainage canals is one piece of the solution puzzle.
A problem 100 years in the making is not going to be solved overnight. It’s up to us to work towards a solution to protect where we live, work, and play. If you live in Florida, connect with local and state governments to encourage positive change for our health and the health of the marine environment. Get the latest updates on HABs across the state by visiting the Florida Fish and Wildlife Conservation Commission’s Red Tide Status page.