Integrating Remote Sensing and Field Observations: A Water Quality Framework for Coral Reef Management in Puerto Rico
Puerto Rico’s neritic coral reefs are in a critical state, having lost over 70% of their substrate cover. Effective restoration is hindered by limited comprehensive water quality assessments, which are vital for understanding chronic exposure to stressors such as land-based sources of pollution (LBSP). To address this, the Puerto Rico Coral Reef Water Quality Program established a sustainable, archipelago-wide framework that integrates state-of-the-art remote sensing with in situ observations to empower resource managers. The program uses a multi-scale assessment strategy with moderate-resolution (e.g., MODIS, Sentinel-3) and high-resolution (e.g., Landsat 8/9, Sentinel-2) satellite sensors for water quality products such as chlorophyll-a (Chl-a), diffuse attenuation coefficients (Kd490, KdPAR), total suspended matter (TSM), and sea surface temperature (SST). To overcome optical challenges in complex coastal waters, a “virtual station” approach is implemented, strategically positioning measurements several pixels from land to minimize interference from land adjacency and bottom reflectance. The framework standardizes historical datasets from 2002 to the present, establishing regional climatological baselines. By cross-referencing field data with satellite records, the program identifies seasonal and annual trends and significant anomalies. A core component of the program is the development of water quality trigger values (e.g., for Chl-a, SST) tailored to Puerto Rico’s shallow reefs, derived from local data using the 20th and 80th percentiles to establish desired ranges and alert systems for acute disturbances. This integrated monitoring program provides a practical workflow for rapid, accurate, archipelago-wide assessments, ensuring management decisions support the long-term protection and resilience of Puerto Rico’s marine life.
Alba Guzmán-Morales, Environmental Mapping Consultants LLC, [email protected], https://orcid.org/0000-0003-1349-6554
William J. Hernández, Environmental Mapping Consultants, [email protected], https://orcid.org/0000-0002-4314-1634
María Vega-Rodríguez, Puerto Rico Department of Natural and Environmental Resources, [email protected]
