Again? Killer brown algae responsible for 2016 mass fish deaths is blooming

COCOA BEACH — Just when you thought that the Indian River Lagoon might be getting a little better, it's back: the brown algae that kills fish by the thousands is blooming, foreshadowing more doom for the troubled ecosystem.

State biologists say the same algae responsible for the 2016 fish kills — the worst on record — is growing at similar levels again.

"The cell concentrations that we've had in February have been actually quite similar to the cell concentrations in 2016," said Ed Phlips, a professor of algae physiology and ecology at University of Florida.

When algae cell concentrations reached comparable levels in 2016, the algae depleted oxygen dissolved in the water, suffocating fish by the thousands. Fish carcasses filled entire canals in Cocoa Beach.

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Biologists began tracking the "brown tide" algae in January — unseasonably early. While, they say, it, is less extensively distributed than it was two years ago, they are worried that its appearance so early in the year is a warning sign that another large-scale fish die-off is imminent, especially as temperatures in the lagoon rise and the algae growth explodes.

Kayakers paddling the lagoon are already reporting that the water resembles an olive-brown soup. They said they can't see the bottom, let alone the fish or manatees that pass within feet of their boats. Both paddlers and property owners alike fear what is coming if the algae goes on growing like this.

"I think it will start affecting our economy," said Amy DeBoer, of Cocoa Beach, as she set out with her husband, Bill, to kayak at Ramp Road Park, where the lagoon resembled chocolate milk. "People won't want to come here."

Some people said they couldn't remember when the lagoon wasn't brown. Others lamented the days when dolphins and manatees were visible beneath a clear lagoon surface. The days of crystal clear water and sandy bottom may not return for decades, biologists warn.

"People are looking for some immediate response," said Duane DeFreese, executive director of the Indian River Lagoon Council, which oversees lagoon cleanups. "It took Tampa Bay 25 years to recover."

The main algae at play these days — Aureoumbra lagunensis — first showed up in lagoon water samples in 2005 and first reached bloom concentrations here in August 2012.

Now, the algae, mixed with several other algae species, spreads over much of the Banana River, especially between State Roads 520 and 528. None of the algae species are known to be toxic, Phlips said, but pointed out that they still kill fish. The shape and amount of algae particles in the water can clog up the gills of fish and shellfish, such as oysters and scallops, and suck up all the available oxygen in the water, suffocating marine life.

Satellite images of the lagoon's current algae blooms even resemble similar images from the spring 2016 algae blooms. The images show levels of chlorophyll — an indicator of algae blooms — remain high in much of Brevard's portion of the lagoon, due to the mix of single-celled algae, mostly the species responsible for brown tide.

As of Friday, no lagoon fish kills had been reported to a state fish-kill hotline.

During daylight, algae produce oxygen through photosynthesis, replenishing oxygen levels in the water. But at night, the algae consume oxygen. This, coupled with the normal demand for oxygen from fish, crabs and other marine life can cause dips in dissolved oxygen in the lagoon, with the lowest levels just before dawn.

When dense clusters of fish die and rot, bacteria increase, further diminishing the available oxygen in the water.

Winds could help aerate the water, but stagnant days pose more of a threat.

Brown tide algae is so small that it would take 200 of its cells to stretch across the period at the end of this sentence. But biologists warn the harm this tiny algae could inflict on the lagoon is enormous. Brown-tide and other algae blooms block the sunlight that seagrass needs to photosynthesize.

Seagrass is the keystone of the lagoon food web. It's the manatee's main diet. Mutton snapper, lane snapper, gag and red grouper, spotted sea trout, blue crabs and other marine life depend on seagrass for habitat. Studies have shown one acre of seagrass can support as many as 10,000 fish.

Seagrass loss in recent years has boosted the potential for brown tide blooms, Phlips said, because it stabilizes sediments that can stir up and make nutrients available to fuel excess algae. "Because the seagrass communities have suffered a lot ... when there's any kind of rainfall and external nutrient loading, then you're going to have an elevated potential for blooms," Phlips said.

A 2015 study by scientists at Stony Brook University in New York shows that brown tides thrive off of the forms of nitrogen typically found in sewage, which has contributed to the proliferation of the algae in the lagoon and elsewhere.

Recent large sewage spills from Hurricane Irma and the heavy rains during and after — including 20 million gallons spilled in the Satellite Beach area — added nutrients to feed the bloom. But those spills are not considered the sole trigger for the current bloom, scientists said, but one of many sources contributing nitrogen and phosphorus for the algae to feed on. Fertilizers, leaky septic tanks and sewer pipes, air pollution and decades of organic muck buildup on the lagoon bottom also contribute, they said.

"We have hot spots in Banana River Lagoon and Sykes Creek that are very reminiscent of what we looked like going into March 2016," DeFreese said. "So we're concerned. It's very hard to predict what's going to happen."

In March 2016, dead fish blanketed Cocoa Beach canals and dotted the lagoon from Titusville to as far south as Palm Bay.

Biologists aren't sure how brown tide got here, whether the species always resided in the lagoon or was introduced from the ballast water of a boat. In the Long Island area, brown tides have been linked to nutrients from septic tanks polluting the groundwater, then oozing up in the bays.

Brown tide put countless scallop fishermen and clammers out of work in Long Island in the 1980s and has bloomed there almost every year since.

The same brown tide species hit Laguna Madre and Baffin Bay along Texas' Gulf Coast in the early 1990s, killing off seagrass for years. The bloom lasted almost eight years, making it the longest continuous harmful algae bloom ever recorded.

In the summer of 2012, brown tide began in Mosquito Lagoon and moved west to the northern lagoon. It was the first bloom of the species documented in Florida. At that time, it never spread south of Titusville. But as much as 50 square miles of lagoon seagrass had already died a year earlier, after another type of algae bloomed from Titusville to Eau Gallie and a separate, concurrent bloom stretched from Eau Gallie to south of Vero Beach. In all, more than 47,000 acres — 73 square miles — of seagrass would die in the blooms, according to the water management district.

For now, boaters and biologists and fishermen will watch to see whether the brown water grows browner.

"We'll know in two or three weeks," Phlips said of the potential for fish kills similar to March 2016. "Right now it's sort of a wait and see game."

Contact Waymer at 321-242-3663

or jwaymer@floridatoday.com.

Twitter: @JWayEnviro