While the Indian River Lagoon is relatively free of toxic algae blooms right now, residents shouldn’t get too comfortable because more are bound to occur in the future – including blooms of some algae we haven’t seen before.

"This isn't going away anytime soon," Dr. James Sullivan told a large audience at the Emerson Center. "Worldwide, harmful algal blooms are increasing in type, frequency, duration and severity. There are a whole bunch of algae that were never there before ... [and] Florida is the most impacted state in the U.S."

That was also the gist of a talk Sullivan, executive director of Harbor Branch Oceanographic Institute and member of the state’s blue-green algae task force, gave at a public meeting of the Clean Water Coalition of Indian River County in Vero Beach last Thursday.

Algae blooms are caused by nutrient pollution from phosphorus and nitrogen due to fertilizer runoff and leaking septic systems; warming waters due to climate change; and other human impacts related to land use practices, stormwater management and dredging, according to Sullivan.

The scientist said not all algae produce toxins, but even some that don’t, such as the "brown tide" that plagues the northern lagoon, cause plenty of damage by clouding the water and sucking up oxygen.

Toxins produced by algae pose a direct health threat to people, Sullivan said. They include microcystin, which damages the liver; red tide (brevetoxin), which causes respiratory and skin problems; saxitoxin, which causes paralytic poisoning if consumed in fish; and ciguatera, also a type of neurotoxin.

Sullivan said there’s an emerging threat of a new harmful algal bloom just spotted along the U.S. east coast that could make its way into the lagoon, and a large-scale microcystin bloom in Lake Okeechobee that so far has been held back from the St. Lucie estuary by floodgates, but that could enter the lagoon south of Vero in the event of more heavy rain.

"Microcystin is becoming a scourge across the world," Sullivan said "It is very good at exploiting nutrient-polluted waters."

Sullivan said the state of Florida is working on the problem through its recently formed blue-green algae and red tide task forces, which he said may merge in the future. The blue-green task force will hold its fourth meeting this month and issue its first set of recommendations to the governor and the Department of Environmental Protection in September.