Florida Department of Health officials in Collier County are cautioning people to stay away from the 60-acre Lake Avalon, a popular spot for watersports, due to the presence of toxic blue-green algae.
"Do not drink, swim, wade, use personal watercraft, or come into contact with waters where there is a visible bloom," the health department wrote in its cautionary advisory this week. "Wash your skin and clothing with soap and water if you have any contact with algae, or discolored water that smells unpleasant."
Lake Avalon is the centerpiece of Sugden Regional Park southeast of Naples, where there is a gazebo, playground, butterfly garden, sailing center, and a pathway around the lake. On the water, people typically waterski, fish, boat, and swim in the freshwater along a sandy shoreline.
The presence of blue-green algae in Collier County freshwater bodies reflects a broader issue plaguing Florida's freshwater bodies, where the harmful algae are common. The microorganisms thrive in lakes, rivers, and estuaries throughout the region, often blooming when conditions are favorable such as when warm temperatures and nutrient levels are high due to agricultural and urban runoff.
Marine biologists have proven that stormwater and agriculture runoff can feed the outbreaks and make them last longer and be more damaging than they would have been without those man-made nutrients.
"To tackle toxic cyanobacterial blooms, we need to cut back on both nitrogen and phosphorus," said Brian Lapointe, a research professor at Florida Atlantic University's Harbor Branch Oceanographic Institute, who is studying blue-green algae in Lake Okeechobee and the Caloosahatchee River. "Managing both nutrients is crucial because of their combined impact, which often lead to more severe and persistent harmful algal blooms."
Lapointe's research found that human waste played a significant role in fueling these blooms. In urban areas, it's a major source of the nutrients that feed the algae that often are released from old or leaky septic tanks.
Lake Avalon is not alone with its algal woes.
Collier County's waterways have been facing a mixed bag of water quality challenges, according to a report released by Collier County Pollution Control last year that revealed problems with water health across the region.
Blue-green algae became an unwelcome chapter of the larger Southwest Florida history when a bloom set in from late 2017 to early 2019, coating docks and boats in green goo, coloring the water of the Caloosahatchee River green, and causing millions of dollars in economic damage.
The Collier County Parks & Recreation Administration runs waterskiing and sailing classes in Lake Avalon for those with special needs. Children frolic on the sandy beach where the beach toys are tied down at the water's edge, so they are always available for everyone.
The health department cautioned that blue-green algae can produce harmful toxins even when not visible as a bloom, and the elderly, children, and immunocompromised "may still be at risk even at low concentrations and should avoid any exposure."
Blue-green algae and red tide are unique from one another; however, they both can smell awful, can suck all the oxygen from the water and kill fish that wash up on shore and rot, and can last for months at a time if not longer.
Blue-green algae are most noticeable when freshwater and brackish streams, rivers, and lakes are coated in a slimy coating of green floating on the water. In canals, blotchy blue and green patches pile up in the dead-ends of canals and start to rot.
The situation at Lake Avalon underscores the delicate balance between human activity and natural ecosystems in Florida.
Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health.
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