Task force focuses on preventing HABs

Posted 8/8/19

FORT PIERCE — Members of Florida’s Blue-Green Algae Task Force said emphasis should be on preventing harmful algal blooms (HABs) and expressed concerns about potential side effects of trying to …

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Task force focuses on preventing HABs


FORT PIERCE — Members of Florida’s Blue-Green Algae Task Force said emphasis should be on preventing harmful algal blooms (HABs) and expressed concerns about potential side effects of trying to treat HABs in the water.

Preventing, combating and cleaning up HABs were among of the topics of discussion at the Aug. 1 meeting of the task force, held at Harbor Branch in Fort Pierce. The group is tasked with helping to help the state get the most “bang for the buck” with projects to prevent and address HABs. The scientists on the task force will help set the criteria for evaluating technologies proposed to deal with HABs.

“I think we should be squarely focused on prevention,” said Dr. Wendy Graham, director of the Water Institute at the University of Florida. “Clean up is important, but not the top priority.”

“If we are going to start cleaning nutrients out of the water, we need to understand how do the nutrients cycle, which ones are we cleaning,” said Dr. James Sullivan, executive director of Florida Atlantic University’s Harbor Branch.

Habitat restoration goes along with HAB prevention, added Dr. Valerie Paul, director of the Smithsonian Marine Station at Fort Pierce. Restoring wetlands north of the lake and the marshes around the edges of the lake would help clean the water.

Cleaning up or treating a HAB includes challenges.

“Trying to clean something up in a canal is radically different than trying to clean up a bloom that is hundreds of acres on Lake Okeechobee,” said Dr. Thomas Frazer, Florida’s chief science officer. It might be different in a lab-based experiment, might be different in a canal, might be different in an open water situation, he said.

“Anything introduced into a water body to combat algae would have to be species specific,” said Dr. Sullivan.

“Not all algae are bad,” he said. “Algae are the base of the food chain. If we destroy all the algae in a water body, the ecosystem collapses.”

Dr. Sullivan added that not all cyanobacteria (called blue green algae) bad. Certain species of blue green algae are the dominant organisms in the ocean and in freshwater, he explained.

“It has to be almost species specific if you start to introduce some kind of chemical agent that is going to work on the algae itself,” he said.

“I don’t know if we can even imagine all of the potential consequences,” said Dr. Graham.

“If you introduce a biological agent of some kind there are always risks,” said Dr. Frazer.

“When using organisms to combat a bloom, we should ask, is it natural? Is it native?” said Dr. Michael Parsons, professor of marine science at Florida Gulf Coast University and director of the Coastal Watershed Institute and Vester Field Station. He said if they can use natural organisms that are native to Florida, that “would receive high marks from me.”

Dr. Sullivan said preventing or combating a bloom in the lake would require they understand the bloom dynamics of the species of blue green algae involved. “Is there a limiting factor for that species? If we target a particular nutrient, will it keep the bloom down?”

He said there are usually a combination of things involved.

Dr. Frazer said solutions that work in the lab may not work in open water.

“You can introduce a biological agent into a beaker and get a result,” he said. “It’s incredibly difficult to carry that out on a large scale.”

Dr. Sullivan said microcystis seems to be the main problem currently in Lake Okeechobee. He said they should find a way to deal with it in the winter when it hibernates on the bottom of the lake or when a bloom is small. “Start targeting your efforts right there,” he said. “Don’t wait for a large bloom.”

“We want to be focusing on technologies that can clean up the drivers of the blooms and not let them get started,” said Dr. Graham.

Dr. Sullivan said he is concerned about suggestions they use chemical controls on algae in the lake. He said chemicals used to control algae could have an effect on human health. He added that he is also worried how long the chemical would remain in the system.

“You can’t just wholesale spray a chemical algaecide over the lake,” he said.

Dr. Paul said killing the blue-green algae could create more problems.

“For blue green algae that are toxic, you will have immediate toxin release,” she said. In addition, “the degradation of that dying material will cause low oxygen to the environment and potentially cause another bloom or death to organisms that could prevent another bloom.

“Ultimately we are looking at nutrient reduction as the solution,” said Dr. Parsons. “If you are just killing it and putting it on the bottom you are not reducing the nutrients.”

Dr. Parsons said the Caloosahatchee and St. Lucie estuaries have varying salinity levels, which adds another complicating factor when dealing with algal blooms.

“If we kill the cells, we are going to release that material to the environment,” said Dr. Paul. “It releases all of the nutrients that are bound up in those cells.” She said it might not be possible to design a testing facility that could fully anticipate all of the consequences.

“If there is a byproduct or a waste product of this technology, how do you dispose of it?” asked Dr. Frazer. “It does it create a larger problem.”

Killing the blue green algae in the water could also create another problem, said Dr. Sullivan. “If you kill a mass of microcystsis, the aerosol toxin levels will go way up because the toxins are released.”

He said there is also research that indicates once microcystin is free in the water, if that water is sprayed on plants, the microcystin can get into the plants.

Dr. Sullivan said a lot of strains of Microcystis (the blue green algae most commonly connected with toxins in the Lake Okeechobee waterway) are not toxic.

“There are specific cues that can flip it from being nontoxic to toxic,” he said. “Whether or not they become toxic is also an environmental trigger.”

“The genes that produce these compounds are known and they can be monitored,” said Dr. Paul. “They are not always toxic. Sometimes they have the genes to produce toxins but don’t turn them on. Sometimes they don’t even have the genes to produce toxins. A lot of people have studied this but it is not fully understood.”

Dr. Sullivan said blue green algal blooms are a problem worldwide.

“What drives blooms in large lakes in China is not the same thing that happens in Lake Okeechobee,” he said. There are different environmental factors.

Another option is to remove the blue green algae from the lake.

“If you do remove the biomass, there has to be a disposal method,” said Dr. Parsons. “One possibility would be doing a second stage treatment, maybe an ozone style, peroxide style treatment. Then how do you dispose of that?

“If somebody has a mechanical removal method, they should have a plan for disposal,” he said.

If someone can create a good technology for dealing with algal blooms, there is a worldwide need, there would be a lot of customers,” said Dr. Sullivan.

“It’s not just a Lake O problem,” agreed Dr. Graham. “Any technologies developed can be applied statewide.”

“I think human health and human exposure should be the priority, and after that the ecological value of the water body,” said Dr. Sullivan.

“There is cyanobacteria in every little lake and pond in the world,” he said. It’s part of the natural system. The problems occur when the cyanobacteria bloom.

“Nutrient reduction approaches are valuable,” said Dr. Frazer. “We want to try to tackle things at the source. He said with some algae treatment technologies there could be potential negative environmental consequences. There could also be by-products of the technologies that are harmful to the environment.

“The risks related to managing nutrients are lower,” said Dr. Graham. “If nutrients are an issue, the investment should be in reducing them before they get into the water body.”

“Controlling the nutrients will control the bloom,” agreed Dr. Parsons.

Dr. Graham said more storage is needed to clean the water before it goes into the lake.

“When you build the storage to hold the water, you are going to have algal blooms in that reservoir,” she said. “I can envision treating it in that area — not in Lake Okeechobee.”

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