Near real-time monitoring of the Biscayne Bay Watershed (South Florida, USA) and major tributaries by water quality research buoys

Biscayne Bay (South Florida) is a subtropical estuary that requires freshwater inputs to maintain its ecological balance. Over the past 50+ years, the bay has been disrupted by contaminated freshwater released from tributaries and canals, negatively affecting its water quality. Specific areas of the bay have been recognized as impaired with respect to nutrients, chlorophyll and bacterial contamination. High human population densities in cities and municipalities within Miami-Dade County significantly influence urban water discharges with large amounts of pollutants released to relatively small areas. In August of 2020, 2021, and 2022, the negative consequences of continued pollution inputs triggered nutrient pulses resulting in significant fish kills followed by atypical algae blooms. To understand these events, we deployed water quality research buoys to monitor the complex system of environmental nutrient contamination in the freshwater canals and saltwater marine environments of Biscayne Bay. The system was designed to produce real-time continuous data for a variety of water quality parameters including chlorophyll a (Chl-a), conductivity, dissolved oxygen (DO), fluorescent dissolved organic matter (FDOM), pH, salinity, temperature, and turbidity. The buoys were strategically positioned in segments of the bay and major outfalls of tributaries and canals. The water quality data collected from the buoys gave a deeper understanding of normal baseline conditions of the tributaries and bay. Seasonal fluctuations of these parameters are significantly different in the dry and wet seasons with tidal influence evident in the managed tributaries. This paper elucidates the utility of a buoy network system for characterizing baseline conditions of various parameters in aquatic environments with varying degrees of environmental degradation. Furthermore, it underscores how a water quality network, comprised of stationary buoys, can serve as an early warning mechanism for stochastic events and provide invaluable data to help guide long-term restoration activities in the Greater Biscayne Bay Watershed. © 2024 Elsevier B.V.