Dying seagrasses, algae blooms found in Tampa Bay could be lingering effects of Piney Point releases

Before Hurricane Ian struck, scientists were monitoring water from the mouth of Tampa Bay near Manatee River, all the way up to Cockroach Bay, on the southeastern shore of Hillsborough County for possible effects of a Piney Point stormwater release.

While monitoring the August release of millions of gallons of stormwater from the Piney Point phosphate plant into Tampa Bay, researchers discovered portions of dying seagrasses and concerning amounts of algae. The most affected areas were Middle to Lower Tampa Bay.

Between August 13 and 25, Piney Point discharged 4.5 million gallons of stormwater near Port Manatee, but Maya Burke with Tampa Bay Estuary Program said water quality results show not much of an immediate impact from those added nutrients, which can feed algae blooms.

Here's a site map of the sampling areas. Joe Bay is S4T3a, Bishop Harbor is S4T2a, Bishop Harbor Deep is S4T2b, Manbirtee Key is S4T1c, Port Manatee S3T6a, Port Manatee Deep is S3T6b, Cockroach Bay is S3T5a, Cockroach Bay Deep is S3T5b, and Emerson is SMR1.

"Conditions looked within normal ranges of what we expect to see in the summertime months,” she said. “Usually, water quality isn't at its best in the summertime because we see so much rainfall in our summer months. And that's really providing a lot of the nutrient load that the bay needs to assimilate over the course of a year during that time."

However, scientists did take note of a marine cyanobacteria, previously known as Lyngbya, now labeled Dapis pleousa. It’s commonly referred to as “snot grass” or “gumbo.”

“We observed it in multiple different ways,” Burke said.