Simulation of Total Phosphorus in Biscayne Bay, USA

Abstract

This research presents a preliminary water quality model for Biscayne Bay (Florida, USA). During the month of December 2018, water quality monitoring stations located in central Biscayne Bay reported total phosphorous concentration (TP) peaks ranging from 0.03 to 0.052 mg/L. Median TP concentrations range between 0.003 to 0.004 mg/L. The water quality simulations presented in this research show that the observed TP peaks were most probably caused by a surge in TP in the Atlantic Ocean waters close to the ocean boundary of Biscayne Bay. Analysis of observed chlorophyll-a concentrations showed that high TP concentrations during December 2018 were not related to algae or phytoplankton bloom. Computational experiments showed that the observed TP peaks are not likely caused by the transport of a sudden release of a high-concentration TP pulse at the coast. Dilution of TP concentration by ocean water limits the spatial reach of coastal contaminant plumes. In testing the TP ocean-surge-origin hypothesis, pulses of 0.044 and 0.024 mg/L were applied to the ocean boundary. The latter pulse generated TP concentrations of around 0.03 mg/L in most of central Biscayne Bay. This estimated concentration is very similar to the TP peaks observed in December 2018. Therefore, those concentration peaks could have originated by a TP pulse of magnitude similar to 0.024 mg/L that occurred in the Atlantic Ocean waters close to the ocean boundary of Biscayne Bay.