A tracer model nowcast/forecast study of the Tampa Bay, Piney Point effluent plume: Rapid response to an environmental hazard.

An emergency discharge of nutrient-rich effluent from the defunct Piney Point fertilizer stack into Tampa Bay at Port Manatee occurred from 30 March-8 April 2021. This resulted in a pollutant plume that evolved over time and space across the entire bay, including its environmentally sensitive marine preserves, and out onto the adjacent continental shelf. As a rapid response to environmental concerns, the plume evolution was simulated using the high resolution, unstructured grid, Tampa Bay Coastal Ocean Model (TBCOM) nowcast/forecast system, with an embedded tracer module that included realistic point discharge rates. Normalized tracer distributions were automatically updated each day, providing 1-day hindcasts and 3.5-day forecasts. Due to mixing and advection, tracer concentration was quickly reduced by two or more orders of magnitude as the plume spread out. Highest tracer concentrations hugged the southeastern Tampa Bay shoreline during the first week. Lower tracer concentrations were gradually advected to the western side of Tampa Bay, and the tracer was slowly flushed out of the bay to be transported primarily northward along the coast. The modeled plume evolution served as principal guidance for coordinating environmental monitoring by state, local and academic personnel. The model results also provide a basis for future multidisciplinary studies.

Initial estuarine response to inorganic nutrient inputs from a legacy mining facility adjacent to Tampa Bay, Florida.

Legacy mining facilities pose significant risks to aquatic resources. From March 30th to April 9th, 2021, 814 million liters of 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. An initial phytoplankton bloom (non-harmful diatoms) was first observed in April. 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 demonstrate adverse water quality changes in response to abnormally high and rapidly delivered nitrogen loads.

Towards integrated modeling of the long-term impacts of oil spills.

Although great progress has been made to advance the scientific understanding of oil spills, tools for integrated assessment modeling of the long-term impacts on ecosystems, socioeconomics and human health are lacking. The objective of this study was to develop a conceptual framework that could be used to answer stakeholder questions about oil spill impacts and to identify knowledge gaps and future integration priorities. The framework was initially separated into four knowledge domains (ocean environment, biological ecosystems, socioeconomics, and human health) whose interactions were explored by gathering stakeholder questions through public engagement, assimilating expert input about existing models, and consolidating information through a system dynamics approach. This synthesis resulted in a causal loop diagram from which the interconnectivity of the system could be visualized. Results of this analysis indicate that the system naturally separates into two tiers, ocean environment and biological ecosystems versus socioeconomics and human health. As a result, ocean environment and ecosystem models could be used to provide input to explore human health and socioeconomic variables in hypothetical scenarios. At decadal-plus time scales, the analysis emphasized that human domains influence the natural domains through changes in oil-spill related laws and regulations. Although data gaps were identified in all four model domains, the socioeconomics and human health domains are the least established. Considerable future work is needed to address research gaps and to create fully coupled quantitative integrative assessment models that can be used in strategic decision-making that will optimize recoveries from future large oil spills.