More than 200 scientists, policy-makers and students from across the country converge on Sarasota next week for the seventh Symposium on Harmful Algae in the U.S. Local research scientists will be talking about their latest findings on red tide.
The single celled organism Karenia brevis is responsible for causing red tide blooms which are the most prevalent harmful algal blooms in Southwest Florida. The algae release a powerful neurotoxin that kills fish and other marine life including birds, sea turtles and dolphins. A bloom that dissipated this past May is estimated to be responsible for the deaths of about 270 endangered manatees mostly in Lee County. Red tide can also be a respiratory irritant to humans and beaches fouled with washed up dead fish can threaten tourism in the region.
While red tide blooms occur naturally in the Gulf of Mexico, researchers say human-caused nutrient pollution has made blooms worse in recent years. “We have been seeing that the intensities are increasing and the durations of the blooms are increasing,” said symposium presenter and research scientist Richard Bartelson with the Sanibel Captiva Conservation Foundation. “Red tide absorbs nutrients like every other phytoplankton except that it’s better at it. It can take up a variety of forms of nutrients so it doesn’t need dissolved nutrients and it can take up organic nutrients.”
Currently, no red tide blooms are present in the region, but water sampling over the last few weeks has shown Karenia brevis to be present in higher than background levels. “Still low levels over the last few weeks and it is not surprising because this is the time of year that it typically starts,” said Florida Fish and Wildlife Conservation Commission research scientist Leanne Flewelling. “So the question is ‘Are conditions going to be right to concentrate Karenia brevis to cause a bloom and move it inshore?’ And it’s still too early for us to say.”
Heather Barron is Clinical Director at the Clinic for the Rehabilitation of Wildlife on Sanibel, or CROW, and will be speaking at the symposium about red tide’s impact on birds and sea turtles. About 8% of the clinics 4,000 yearly patients is due to red tide poisoning and Double-crested Cormorants are particularly susceptible.
“In the past 18 months we saw about 320 Double-crested Cormorants affected by brevetoxicosis or red tide poisoning,” said Barron. “That is basically adding up to about $75,000 a year in medical care that these animals need because of this problem.”
The symposium is October 27-31 at the Hyatt Regency in Sarasota.