For a third straight year, Utah officials are warning residents that a toxic algae bloom has made parts of Utah Lake near Provo unsafe for recreation.
State and county agencies said Tuesday that recent tests on water samples showed high levels of toxin-producing cyanobacteria in the waters of Provo Bay.
Other parts of the lake are not affected by the algal bloom and considered safe for recreation.
Blue-green algae occur naturally in many freshwater systems and can proliferate rapidly under the right conditions of warm weather, plentiful sunshine and still, nutrient-rich water.
They can be fed by runoff from farms, lawns and industrial facilities.
Large quantities can be dangerous to people, animals and fish.
Humans exposed to the bacteria can exhibit headaches, fever, pains and nausea.
Meanwhile, red tide algae are blooming with an increase in concentrations in Sarasota County, a Florida Fish and Wildlife Conservation Commission report says.
According to a June 8 report from the FWC, using 28 samples, FWC found amounts ranging from background to medium concentrations.
The increase in the algae bloom resulted in dead fish on Englewood Beach over the past week. Respiratory irritation was also reported at Englewood Beach, Lido Key, Manasota Beach, Nokomis and Venice North Jetty, Siesta Key and Venice Beach, the report said.
On Monday, Siesta Key had a "heavy" sighting of dead fish, a few dead jellyfish and "slight" respiratory irritation, with some coughs and sneezes heard in about 30 seconds, according to the visitbeaches.org report posted by Mote Marine Laboratory.
The algae blooms can start about 40 miles offshore, said Tracy Fanara, a staff scientist and program manager at Mote Marine Laboratory and Aquarium.
Blooms come up to the surface with rising water caused by temperature differences and can wash up on shore due to currents and wind.
A toxin is released if algae are dying or stressed. Fanara said studies have shown ideal water temperatures for the algae cells are between about 60 and 86 degrees, Fanara said.
If levels are above or below the range, cells can become stressed.
"Cells can be naturally dying," Fanara said.