Continuous nutrient monitoring in coastal waters is essential for understanding ecosystem dynamics and managing water quality. Recent advances in sensor technology and decreasing costs have facilitated the expansion of real-time in situ water quality networks. Traditionally, these networks rely on multi-parameter sensors that measure core parameters such as temperature, salinity, pressure, and dissolved oxygen, and often include fluorometers for various optical measurements. While these sensors are reliable, affordable, and relatively low-maintenance, they generally lack direct nutrient detection capabilities. Only a limited number of in situ nutrient sensors are available that are specifically designed for high-biofouling marine environments.

To address this limitation, in 2020, as part of a regional initiative, we tested a commercially available nutrient sensor and integrated it into the River Estuary Coastal Observing Network (RECON). Established in 2007, RECON consists of nine monitoring stations throughout the Caloosahatchee River and Estuary in southwest Florida. The Shell Point site, located at the mouth of the river, was selected for this test because it experiences the greatest tidal variability and salinity fluctuations, up to 25 PSU. Initial testing produced promising results, although several operational challenges were identified. A longer deployment period was needed to evaluate the sensor’s long-term feasibility and stability. Building upon the initial deployment, this study further assesses the sensor’s performance, compatibility, and potential to enhance continuous nutrient data collection in dynamic coastal environments.