Marcus Beck , Andrew Altieri, Christine Angelini, Maya Burke, Jing Chen, Diana Chin, Jayne Gardiner, Katherine Hubbard, Yonggang Liu, Cary Lopez, Miles Medina, Elise Morrison, Edward Phlips, Gary Raulerson, Sheila Scolaro, Edward Sherwood, David Tomasko, Bob Weisberg, Joe Whalen

From March 30th to April 9th, 2021, 814 million liters of legacy phosphate mining wastewater and marine dredge water from the Piney Point facility were released into lower Tampa Bay (Florida, USA). This resulted in an estimated addition of 186 metric tons of total nitrogen, exceeding typical annual external nitrogen load estimates to lower Tampa Bay in a matter of days. Elevated levels of phytoplankton (non-harmful diatoms) were first observed in April in the lower Bay. Filamentous cyanobacteria blooms (Dapis spp.) peaked in June, followed by a bloom of the red tide organism Karenia brevis. Reported fish kills tracked K. brevis concentrations, prompting cleanup of over 1600 metric tons of dead fish. Seagrasses had minimal changes over the study period. By comparing these results to baseline environmental monitoring data, we conclude that many of the biological responses observed after the release from Piney Point are abnormal relative to historic conditions.