Sarasota Bay sees major water quality gains, state says. Other local waters doing worse

Sarasota Bay’s water quality has significantly improved, according to state regulators, who are proposing its removal from Florida’s list of nutrient-polluted waters.

The Florida Department of Environmental Protection assesses the health of water bodies every two years. Estuary scientists who oversee the health of the bay are celebrating the news, but they also have some advice to keep the progress going.

Sarasota Bay’s watershed spans about 150 square miles of the Intracoastal Waterway along Sarasota and Manatee counties, where it provides vital wildlife habitat, fishing and boating grounds.

Sarasota Bay Estuary Program director Dave Tamasko agrees that the bay’s health has seen a big boost.

“If you look at the last eight years, it’s a clear improvement in less algae,” said Tomasko, whose organization oversees the restoration and protection of the bay through the National Estuary Program.

While parts of the bay have faced setbacks, including red tide algae blooms and pollution from the Piney Point wastewater spill, Tomasko said the overall trend has been a decline in nutrient pollution.

Four segments of the bay — Sarasota Bay, Roberts Bay, Little Sarasota Bay and Blackburn Bay — are set to be de-listed for nutrient pollution, according to a draft list published this month by FDEP.

Seagrass beds, another indicator of estuary health, also appear to be recovering in some areas after several years of losses, Tomasko said.

Estuary program scientists hope the increase will be reflected in Southwest Florida Water Management District’s next seagrass mapping survey, which will be released in 2024.

Meanwhile, other area waters have seen an increase in pollution, FDEP says, and will soon be listed as “impaired.”

Tomasko said the estuary program is taking stock of what is going well and what can still be done to improve water quality as it formulates its next improvement plan for the bay.

What is helping local water quality?

The state measures chlorophyll-a — a green pigment that helps marine plants photosynthesize — as an indicator of how much algae is in the water column.

In 2022, chlorophyll-a dropped to the lowest levels seen in eight years for many parts of Sarasota Bay, data in the state’s report shows.

In addition to those measurements, the change has been observable in cleaner, clearer water, Tomasko said.

What caused the improvement?

Tomasko argues that it wasn’t a decrease in rainfall. Over the eight-year period, rainfall amounts did not correspond with levels of chlorophyll in the water, data compiled by SBEP show.

Instead, he cites major investments in infrastructure by local municipalities that have led to a drop in wastewater discharges and pollution.

They include upgrades to Manatee and Sarasota counties’ wastewater treatment plants and projects to retrofit outdated stormwater systems.

Going forward, SBEP is calling for continued investments in controlling pollution from both old and new development.

“We need to make sure that an increase in population growth doesn’t cause an increase in pollution loads,” Tomasko said.

“At the same time, an acre of Lakewood Ranch doesn’t produce nearly as much pollution as an acre of downtown Bradenton,” Tomasko said. “Those older neighborhoods don’t have near as much treatment.”

That can be amended with more retrofit projects, he said.

Now that the state requirement for nutrient pollution has been met, SBEP is also working to develop stronger water quality targets. Tomasko said that the state’s requirements don’t go far enough to limit nitrogen, a nutrient that can fuel harmful algal blooms like red tide.

“There is now not a regulatory requirement to further improve water quality,” Tomasko said. “We need to make sure this does not slip away again.”

He said he hopes the region can serve as a model for other areas of the state.

“If you want to fix Indian River Lagoon and Biscayne Bay, do what we’re doing here in Sarasota Bay,” Tomasko said. “Let science drive restoration.”

Scott Moore, a local fishing captain, agreed that he has seen improvements in Sarasota Bay’s water quality.

“The water has gotten a lot better down there,” Moore said. “It’s recovering from that red tide we had.”

Moore urged local leaders to continue to work on improvements.

“The county needs to look at pockets that are still on septic tanks,” Moore said.

Other Bradenton-area waters on impaired list

Some local waters are on a different draft list of water bodies to be declared “impaired,” which means they do not meet water quality standards set by the state.

Water bodies can be impaired for different reasons, including too many nutrients in the water or too much bacteria.

In Manatee County, waters on the draft impaired list include Anna Maria Sound and a segment of the Manatee River, from west of the Braden River to Lower Tampa Bay, both of which have seen an increase in nutrient pollution.

In Anna Maria Sound, Tomasko said it could be a “hangover” from Piney Point pollution.

“That was the area that I think got hit hardest by Piney Point,” Tomasko said. “You can have a longtime impact from an episodic event.”

Moore said the Lyngbya algae are still overabundant in some local waters. When Lyngbya dies, it sucks the oxygen from the water column, driving away fish, and forms thick, stinky mats at the water’s surface.

A dozen Manatee County water bodies, mostly inland creeks, are also on the draft impaired list because levels of fecal bacteria are too high in the water.

Once a water body is placed on the impaired list, FDEP works with local governments to create a plan to bring it back in compliance.

“If enough people demand it of officials, good things can happen,” Tomasko said.

This story was originally published October 24, 2023 at 5:50 AM.