INDIAN RIVER, Fla. — A federal researcher has found three varieties of toxins from microscopic algae that he said are responsible for the deaths of manatees, dolphins and pelicans in the Indian River Lagoon in the past year.
Scientists said manatees have been eating more of the toxins, which stick to seaweed, because algae blooms have killed the sea grass they normally eat.
Peter Moeller, a research chemist at the National Ocean Service in Charleston, said he still doesn’t know which algae are producing them and they don’t know how to eliminate it.
His lab collected the algae in May in a spot where many manatees were dying. More than 100 manatees, 51 dolphins and 300 pelicans have died from unexplainable causes in the lagoon in the past year.
Florida Today reports Moeller’s lab tested the algae toxins on mice neurological cells and human breast cancer cells.
Moeller said the next step is to describe the molecular structure of the three “suites” of toxins, then determine if the same toxins exist in the manatee, dolphin and pelican tissues.
The Indian River Lagoon, which is one of the largest estuaries on the East Coast, has been choked by a thick, brown sludge on and off for the past few years. At times, there’s been too much and other times, there’s too little. The excess algae is thought to be the result of excess nutrients such as nitrogen and phosphorous. As the brown tide lingers, fish and sea grass are also disappearing.
The St. Johns River Water Management District committed up to $3.7 million in April to research a bloom of the same algae species that occurred last year and a toxic algal bloom that occurred in 2011.
Earlier this week, Florida Senate President Don Gaetz announced that a select committee will study the potential environmental impact of discharges from Lake Okeechobee into Indian River Lagoon and other nearby bodies of water. The discharges are controlled by the U.S. Army Corps of Engineers. There have been concerns that too much freshwater is coming from the lake into estuaries that rely on a mixture of both fresh and salt water.
Brian LaPointe, a researcher with Florida Atlantic University’s Harbor Branch Oceanographic Institute in Fort Pierce, suspects septic tanks, sewer plants and reclaimed water may be the culprit behind the harmful algae bloom. His tests on the algae showed it includes nitrogen in forms that normally occur after passing through a long digestive tract such as a human’s or through the biological processes at a sewage treatment plant.
In 2010, Nova Southeastern University used an acoustic sensor to survey the lagoon’s drift algae from Titusville to Sebastian Inlet. They found drift algae had increased by 46 percent in two years, to 102,162 metric tons over the 109 square-mile study area.