Red tide, Lyngbya algae blooms persist in Manatee County waters

Blooms of red tide and Lyngbya algae continue to impact waters around Manatee County this week.

Bloom levels of the red tide organism, Karenia brevis, were observed in recent samples in lower Tampa Bay near Port Manatee and in the Terra Ceia Aquatic Preserve, according to the Florida Fish and Wildlife Conservation Commission.

“Low” and “very low” concentrations of K. brevis continue to be observed in the vicinity of the Sunshine Skyway Bridge, and one water sample collected on Monday showed a very low concentration at the northern tip of Anna Maria Island.

Significant levels of the algae were not found elsewhere around Anna Maria Island and Longboat Key, according to recent sampling data.

Fish kills thought to be associated with red tide were reported in Manatee County over the past week, while respiratory irritation was not, according to FWC.

The patchy red tide bloom affecting the Tampa Bay area has grown particularly strong around Pinellas County in recent days, where breathing trouble and thousands of dead fish have been reported along area beaches. Two recent samples in Gulf coast Pinellas County waters show that red tide has reached “high” concentrations there, or more than 1 million cells of K. brevis per liter.

FWC is expected to issue its next red tide report on Friday.

Lyngbya bloom still present

An unusually large bloom of the cyanobacteria, or blue-green algae, called Lyngbya continues farther south in waters around Anna Maria Island and other parts of coastal Manatee County.

Unlike with red tide, there are no weekly reports from the state on the status of Lyngbya blooms. But scientists and environmental advocates are filling the gap by keeping a close watch on the potentially harmful algae.

Lyngbya is naturally occurring, but when overabundant it can crowd out vital seagrass beds. Mats of the algae carried to the surface deplete oxygen from the water as they decompose, which can cause fish kills or drive marine life away. The debris can also create an unsightly and smelly mess along the shoreline.

Scientists and residents alike say they have never seen a bloom this big, and many see the Piney Point discharge as the likely culprit.

The wastewater discharged in May contained phosphorous and nitrogen, both nutrients known to fuel algal blooms.

The groups monitoring the Lyngbya algae bloom say that conditions have gotten better in some areas and worse in others this week.

Rusty Chinnis, a board member of Suncoast Waterkeeper, has been routinely checking on the bloom by air and sea.

“It’s sort of a mixed bag. There’s not as near as many floating mats of it,” Chinnis said. “But it’s still at the bottom, so I think there’s more to come.”

Chinnis said he observed the algae in several new places this week, including around Miguel Bay and Rattlesnake Key in the Terra Ceia Aquatic Preserve. He also noted waters are still discolored and smelly in some areas.

Sarasota Bay Estuary Program is also keeping tabs on the bloom. As of Wednesday, water in some areas of Palma Sola Bay and Anna Maria Sound looked better, according to executive director David Tomasko, while others remained the same or had more algae impacts than before.

“Whatever is happening, we’re still in the middle of it,” Tomasko said. “There’s still a lot of it forming out in the bay.”

The algae still on the ocean floor could continue to detach and send more waves of detritus to the surface and the shore.

“It’s like a conveyor belt,” Tomasko said.

This story was originally published June 17, 2021 at 5:00 AM.