Mote Marine's ozone experiment works, sort of, but it's not the silver bullet to kill Red Tide

The ozone machine Mote Marine Laboratory was testing ran for five days, trying to clean up a canal on Damfino Street in Boca Grande. [Courtesy of Mote Marine Laboratory]
The ozone machine Mote Marine Laboratory was testing ran for five days, trying to clean up a canal on Damfino Street in Boca Grande. [Courtesy of Mote Marine Laboratory]
Published Sept. 26, 2018

In a phone call with his state wildlife commissioners this week, Gov. Rick Scott touted his decision to give Mote Marine Laboratory in Sarasota $2.2 million to run some experiments on stopping Red Tide.

That included using an ozone machine to clean the water.

But the Mote scientist in charge of the ozone experiment, Richard Pierce, says they're done with it and have moved on.

The experiment worked, sort of. But it also underscored the limitations of human efforts to combat or control a massive toxic algae bloom that's covering more than 100 miles of the state's coastline — one that's been called the worst in a decade.

"It's a very daunting task to try to control something like Red Tide," Gil McRae, director of the state-run Florida Fish and Wildlife Research Institute. He was addressing members of the Florida Fish and Wildlife Conservation Commission after Scott's call.

Mote, a nonprofit scientific institution that's funded primarily by donations and government grants, is primarily known for its marine research. However, it also rescues and rehabilitates sea turtles and dolphins.

Its 25,000-gallon tanks where injured or ailing animals swim around are connected to Sarasota Bay. Mote uses a machine that makes ozone to clean the bay water before it reaches the tanks. That's where the idea for using ozone to break up a Red Tide algae bloom came from, Pierce said.

A water molecule has two oxygen atoms in it, while ozone has three. Ozone's oxygen atoms "are highly reactive," Pierce explained. As a result, when ozone comes into contact with the Red Tide algae, "It just tears it apart," the Mote scientist said. "It does the same thing to the toxins."

To test whether their ozone machine could clean up Red Tide in Florida's waterways, Pierce said, the lab got permission from a group of Boca Grande homeowners to test the machine in a canal that he described as "putrefied" with "mud and everything."

According to the Boca Beacon newspaper, the canal was on Damfino Street on the island, but attempts by a Tampa Bay Times reporter to contact Damfino residents failed to turn up anyone who had seen the experiment.

Mote scientists ran the machine for five days, starting on a Monday and not turning it off until a Friday. The machine sucked up water from the canal, hit it with ozone, then pumped it back into the canal.

Two staff members paddled around in a kayak checking the water quality to make sure it was better than before, not worse. Mote director Michael Crosby said earlier this week that dumping bleach into the water would kill the algae, but it would also kill everything else — something Mote wants to avoid.

The result of the ozone experiment was somewhat mixed.

"It works," Pierce said, "but you'd need a much larger unit to tackle it."

At the end of the five days the machine had indeed cleaned the water in the canal and banished the Red Tide. But despite a boom blocking the entrance to the canal, more toxic algae washed into the canal beneath the boom, contaminating it once again.

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"With the tidal action, we can't keep all the (algae) out," Pierce said. "We did not get to the point of clarifying the water."

To completely clean the canal, he said, would require a machine so large that it would cost more than $1 million, and perhaps as much as $2 million, he said.

"The concept would be to have a couple of machines that are big enough," he said, "and load them on barges and go around and start cleaning those canals."

But don't look for Mote to do that.

"Mote is not interested in getting into the canal-cleaning business," Pierce said. "We leave that to others."

Instead, Mote is now starting to test other types of technology to try combating Red Tide. Pierce did not want to disclose what that might be, but state officials said it involves hydrogen peroxide and the use of enzymes.

Asked for reaction to the fact that Mote has moved on from its experiment with ozone to battle Red Tide, a spokesman for the governor said the money can be used for the center's broader efforts to address algae blooms.

"This funding was provided to Mote Marine as they continue to work with FWC and other partners in a multifaceted approach to combat Red Tide and put forward innovative mitigation technologies," said McKinley P. Lewis. "We look forward to seeing their work.

Contact Craig Pittman at Follow @craigtimes.