The old Piney Point phosphate plant has dominated the news cycle in Tampa Bay for weeks. Wastewater from the reservoir was pumped into Tampa Bay to avoid a catastrophic breach on land. The environmental restoration of Tampa Bay is an internationally recognized success story. In the 1970s, excessive nitrogen loads from commercial activities and urban growth were polluting the bay. In 1991, The Tampa Bay Estuary Program (TBEP) was formed. TBEP set a science-based goal that the bay would support as much seagrass as it did in 1950, before pollution and algae took over. In 2015, the goal was surpassed! Seagrasses now cover over 40,000 acres of Tampa Bay’s seafloor (about equivalent to the land area of the City of St. Petersburg). This achievement was accomplished through a voluntary public-private partnership called the Tampa Bay Nitrogen Management Consortium, the purpose of which is to proactively manage nitrogen loads that enter the bay.

Tampa Bay is the largest open water estuary in Florida. The Hillsborough River is the largest freshwater source to Tampa Bay, with the Alafia, Manatee, and Little Manatee rivers the next largest sources. In addition, there are over a hundred small tributaries, rather than a single river emptying freshwater into the bay. Its large watershed covers portions of four Florida counties (Pinellas, Hillsborough, Manatee and Pasco) and approximately 2,200 square miles. Tampa Bay’s habitats include mangrove hammocks, seagrass flats, softbottom habitat, hardbottom habitat, and artificial reefs; all of which support critical fish and wildlife populations. Tampa Bay also has a shipping channel and smaller boating channels, all of which support a robust commercial and recreational fishing economy, nature-based tourism, and oyster and shellfish aquaculture operations in this part of the bay.

The Tampa Bay Estuary Program and public-private partners are committed to reducing nutrient pollution, no matter the source. As such, at the end of March 2021, when a seepage point in the liner in the new gypsum stack south (NGS-S) at the Piney Point facility in Manatee County started impacting the bay, the community rapidly mobilized. Environmental managers, marine scientists, conservation organizations, and marine industries have been hard at work coordinating over email, zoom, phone, text, and VH radios.

To prevent collapse of the 480-million-gallon south storage reservoir, nutrient rich water, a mixture of stormwater, seawater, and process water, was pumped through pipes, out into Tampa Bay through Port Manatee. As of April 9th, approximately 215 million gallons have been discharged to Port Manatee and into Tampa Bay. Approximately 232 million gallons of water remain in the NGS-S. At its peak, 38 million gallons of water were being discharged to the bay each day. For better or worse, the draining of that water into Tampa Bay helped to avoid a public-safety disaster on land. However, environmental concerns remain.

While we cannot predict the impact that these discharges will have on Tampa Bay, one of the biggest ecological concerns are algal blooms of either phytoplankton (microscopic algae) and/or macroalgae (large seaweed). The primary pollutants of concern in the discharge water are high concentrations of phosphorus and nitrogen (primarily ammonia nitrogen) which can stimulate algal blooms and further affect the bay’s seagrass, fish and wildlife resources. NOAA has reported an area along the coast of Manatee County which is showing high levels of chlorophyll. How this event ultimately impacts the bay is highly dependent upon how much nutrients are retained and recycled in the bay. Therefore, understanding where the plume of the discharge is being circulated and diluted in the bay is crucial. University of South Florida College of Marine Science Ocean Circulation Lab is working on forecasts to further aid our efforts and understanding in this regard. Managers are particularly concerned about the shallow backbays of the southeastern shore, from Cockroach Bay south toward Sunshine Skyway Causeway near the mouth of the Manatee River.

In addition to understanding where the plume water will move within the bay, The Tampa Bay Estuary Program is working with regional partners to coordinate and synthesize monitoring efforts for water quality, benthic habitats, seagrass, macroalgae, and fisheries monitoring data. TBEP efforts and data can be found at their dashboard . The dashboard is a synthesis of data that can be used to assess baseline conditions prior to discharge and to evaluate changing water quality conditions as new data become available. All data are provisional and subject to revision.

While the impacts of the release are daunting, Tampa Bay is resilient. Per the Florida Department of Environmental Protection April 9^th press release, “all discharges of untreated water to Port Manatee are currently ceased. As we deploy innovative technology on-site, the Florida Department of Environmental Protection’s (DEP) goal is to ensure that any future required discharges to the port are treated to reduce nutrients entering surrounding waterways and minimize possible ecological impacts such as algal blooms.” In a statement Tuesday, April 13^th Governor DeSantis said, “We want this to be the last chapter of the Piney Point story. So today, I’m directing the Department of Environmental Protection to create a plan to close Piney Point.” The governor said he’s requested a team of engineers and scientists from the DEP to develop plans for the permanent closure of the site.

The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) and Florida Sea Grant have experts in water quality, harmful algal blooms, sediment nutrient flux, and estuarine habitats. Our scientists have been involved in the regional conversations and associated response. Multiple agencies and organizations are monitoring the bay using macroalgae monitoring protocols that UF/IFAS Extension Sea Grant agent Betty Staugler developed in 2019 to monitor macroalgae in Charlotte Harbor. This rapid response assessment will allow resource managers to quickly characterize conditions before a macroalgal response occurs and then track the balance between macroalgae and seagrass as they react to the nutrient rich discharge waters. Macroalgae and water samples are being analyzed by Dr. Elise Morrison at the UF Center for Coastal Solutions who will be conducting nutrient source tracking with stable isotopes.The faculty listed in the blog linked here, can answer media questions regarding the ongoing Piney Point Reservoir (Manatee County) issue.

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