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When will red tide go away? It’s not looking good

Scientists warn red tides will get worse

Red tide in Manatee County persists and scientists are warning that it may get worse into the future.
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Red tide in Manatee County persists and scientists are warning that it may get worse into the future.

The persistence and severity of one of the worst red tides to hit the shorelines of Manatee County is raising a lot of questions and leaving scientists scrambling to find answers for a future many see as grim.

The current bloom, though in Manatee County for only a little more than two weeks, has been around since October. From Aug. 7 to Aug. 15 alone, red tide claimed the lives of 15 dolphins and more than 165 sea turtles in Gulf waters.

Vincent Lovko, staff scientist and program manager for Phytoplankton Ecology at Mote Marine in Sarasota, said red tide season is typically from late summer to late fall. Lovko said from September to October is typically when red tides reach their peak of severity so there is concern across the coastal communities that this bloom has yet to do its worst as conditions ripen for it to increase.

“It doesn’t always fit that pattern and certainly, this one hasn’t,” Lovko said. “This one has kind of expanded and contracted, but most recently since May, it’s been on an upward trajectory in expanding in size and hasn’t appeared to slow.”

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Gretchen Lovewell, Mote Marine’s stranding investigations program manager performs a necropsy on a Kemp’s ridley sea turtle on Aug. 7. This year’s red tide has killed several sea turtles, manatees and up to 13 dolphins to date. Conor Goulding Mote Marine Laboratory

As of Friday, Manatee County’s red tide count has remained in the high category, which is more than a million cells per liter of the bacteria Karenia brevis, which when fed nutrients creates red tide. Lovklo said there are areas around Mote Marine where they do routine tests that are counting in the 80-to-90 million per liter range.

“Which is kind of ridiculous,” Lovko said. “It might be the highest counts we’ve ever had. It’s still only August so we are a little way from when you would normally expect to see a bloom begin to terminate, but we are still into that season where conditions are in favor of it sticking around.”

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This year’s red tide ranks amongst one of the most severe, but it’s not unprecedented.

An 18-month long bloom occurred from 2004 until 2006, though Lovko said scientists aren’t sure if they were actually two separate blooms. Most blooms tend to be patchy and affect a beach here or there before moving on, but the existing bloom is affecting just about every beach from Collier County in the south to Pinellas County in the north.

“This is a problem that is not going to go away,” said Kathleen Rein, a chemist at Florida International University in Miami. “The evidence suggests that we will have increasing blooms in the years to come. We really don’t know what the effects of climate change will be on these blooms. We need to understand these issues and we, as a society, have to find the resolve to deal with them.”

It’s an unfortunate outlook as this year’s red tide has had a devastating impact on local business, tourism and sea life.

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Dead fish still outnumbered beach goers as of Thursday, particularly along the shoreline of the inlet that separates Coquina Beach from Longboat Key and the Gulf of Mexico from Sarasota Bay. This year’s red tide has devastated sea life and scientists are scrambling to understand why. Mark Young myoung@bradenton.com

“It seems the amount of dead wildlife is shocking because there has been so much,” Lovko said. “But if you remember we had a normal pattern in 2012 and then all of a sudden in 2013 we had a bloom where a record number of manatee deaths were recorded. I wouldn’t say this bloom is normal by any stretch of the imagination, but it’s not unprecedented. None of that is to say that this isn’t bad because it is.”

Residents in Manatee County’s Whitfield/Bayshore Gardens neighborhood woke up to thousands of dead fish and a dead shark in their backyards in Bowlees Creek after the red tide carnage started to flow into the waterway from Sarasota Bay Wednesday.

Various species of sport fish have also been affected heavily. Michael Crosby, president and CEO of Mote Marine, is grateful for the rapid response from the Florida Fish and Wildlife Conservation Commission, as well as the Florida Department of Environmental Protection.

“The emergency support will allow Mote’s Stranding Investigation Program to respond to a significant increase in reports of sick and dead sea turtles, manatees and dolphins,” Crosby said.

Mote stands ready, Crosby said, to respond around the clock, “While also working tirelessly to learn all we can from these recovered marine animals. Of course, the Florida fisheries are also hard-hit by this bloom, including large snook in the summer spawning areas along Charlotte and Lee county beaches.

Assessment of the potential long-term damage to fisheries up and down the coast continues.

Capt. Chad Huff found an 80- to 100-pound tarpon floating dead in August near Ding Darling National Wildlife Refuge in Sanibel, where some of the worst fish kills have occurred since a red tide appeared off Southwest Florida in October 2017.

How and when a red tide bloom will end is difficult to predict. A good storm with enough wind and rain can break up a bloom and push it out to sea, “but that doesn’t always work,“ Lovko said. “In 2012 we had a remnant of a hurricane come through and broke it apart, but it came back and was one of the worse we’ve seen.”

Cause and effect

Virtually everyone agrees that it’s nutrients, natural and man made, that feed the bacteria that then creates the red tide. But not everyone agrees just how that is happening.

Lovko said he understands the need for people to point fingers and assign blame, but he doesn’t agree with the notion that Lake Okeechobee is solely to blame. Lovko said recent research has identified up to 12 sources of nutrients that are feeding red tide.

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Mote Marine Laboratory’s ‘Genie’ glider returns from a 15-day mission in the Gulf of Mexico. The winged, yellow torpedo-like device collected data on seven different factors, which will allow Mote scientists to learn more about how blooms of *Karenia brevis*, the Florida red tide algae, occur. Olivia Raney Mote Marine Laboratory

“Certainly estuary flow, but rivers flow into estuaries in Florida and that complicates things,” Lovko said. “It stays there for awhile so we don’t have an open pipe into the Gulf. There are a lot things that use that nutrients including the ecosystem of our fish. If we didn’t have those nutrients, we wouldn’t have fish.

Lovko said when looking at the released from Lake Okeechobee that flow down the Caloosahatchee River into Charlotte Harbor and Pine Island Sound, “How much of those nutrients are making it to the coast? It’s something quite frankly that hasn’t been evaluated in a consistent and methodical way. And people tend to forget this important fact: This bloom started in October, but the major flows from Lake Okeechobee didn’t start until June.”

Lovko said he could not rule out that Lake Okeechobee releases could be playing a part, “But it seems unlikely.”


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FIU marine scientist Jose Eirin-Lopez it’s just the nature of the beast in Florida’s natural makeup.

“With such a unique blend of diverse aquatic environments, a constant source of energy in the form of sunlight all year round, and, most importantly, a persistent increase int he flow of nutrients to the ocean,” Eirin-Lopez said. “South Florida represents a perfect haven for these algae to grow free and without limit.”

Eirin-Lopez said that’s why, “We must worry,” noting increased nutrients, a growing density in population and challenges to adequately manage residual waters packed with agricultural nutrients are worsening the problem.

Rein said it’s a healthy debate within the scientific community and there are other theories that Karenia brevis can also feed on other bacteria. So there is a double-edged sword in that red tide can occur naturally and be enhanced by agricultural runoff. Whether it’s one or the other, or both, “Many scientists believe that the frequency, size and duration of these blooms is increasing,” Rein said.

Dr. Vince Lovko talks about how Mote tests water for Karenia brevis, or the red tide phytoplankton.

Future outlook is grim

If there is a silver lining in this year’s bloom, it has been the opportunity created for researchers to gather important data in hopes of one day to better forecast and predict red tide, and yes, ultimately figure out how to destroy it.

In the meantime, scientists believe it could get worse before it gets better just based on what is going on globally.

“The overall perception is that it’s getting worse worldwide,” Lovko said. “For a lot of reasons. Part of the reason is that we are living on coastal areas more so we are seeing it more, but they are getting worse. We know the addition of nutrients is probably one of the major causes here, but when you get into different blooms, different species, and different environments, the cause can be different.”

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Crews continue to do a great job keeping the shorelines of Anna Maria Island clear from dead fish that continue to float ashore, victims of a persistent and severe red tide outbreak. But the fish kill continues. Mark Young myoung@bradenton.com

With the improvements in technology, the data gathering process is improving. While there are still many missing pieces to the overall puzzle, more pieces are being discovered.

“Nothing is more important than collecting that data that can help us understand the difference between a bad bloom year or a non bloom year or a minor bloom year,” Lovko said. “So you say, ‘OK, what does that do for us now?’ It moves us toward prediction and forecasting capability. It’s like the weather, we don’t necessarily try to change it, but we put a great deal of effort to forecast it and that’s made possible by all the monitoring tools out there. We aren’t there yet, but there is a growing call to make that happen.”

Lovko said it’s all part of solving that puzzle.

“We get closer all the time. We’ve learned a lot about Karenia brevis, where it initiates offshore near the bottom, but haven’t pinpointed it yet. We don’t have the monitoring capability to cover that much water area, but we are getting little pieces of that puzzle. We get a lot of new information and sometimes it’s clear and sometimes it’s blank and think it goes there. How close are we to finishing the puzzle? I wish I could say. I don’t know.”

Is bacteria vs. bacteria the answer?

There are several ways a red tide bloom dies off, whether it’s weather-related, natural or a competing virus or parasite. Lovko said there are particular parasites that attack and kill red tide.

“But it needs a lot more research,” he said. “It is something that maybe we can learn through more research.”

The red tide bacteria is a family member of the Dinofalgellate species, but Lovko said a similar member of the species “plays a major role in controlling natural blooms in the northeast. If it can be effective, then maybe there is a way we can enhance it, but there are many steps to go before we are there.”

The only issue is that other forms of the Dinofalgettate species mimic symptoms of red tide.

“Scientists are very wary, and rightly so, of fusing these biological approaches to tinker with the delicate balance of microbes in coastal waters,” Rein said. “It is quite possible that we could end up with a situation that is even worse than what we have now. Many years ago there was an attempt to use chemical methods to stop the bloom, but this approach has adverse effects on other marine life.”

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