Spatiotemporal Analysis of the Potential Impact of the Masinloc Power Plant on the Thermal Pollution in Oyon Bay, Zambales, and its Correlation to the Seagrass Cover

Abstract. The proximity of power plants to protected seascapes presents a significant environmental concern, yet research on thermal pollution and its effects on marine ecosystems in the Philippines remains limited. This study examined the relationship of thermal pollution from the Masinloc Power Plant on the marine ecosystem of Oyon Bay, Zambales, focusing on seagrass ecosystems. Remotely sensed sea surface temperature (SST) data from Landsat satellites (5, 7, and 8) were used to track SST changes from the pre-operation period (1993-1998) to the operational period (1999-2023). Time series decomposition of SST data indicates a gradual increase in temperature, with emerging hotspots analysis identifying localized thermal pollution near the plant's outfall. A time-lagged correlation analysis revealed a moderate negative relationship (R = -0.47) between increased SST and seagrass percent cover, with a delayed response of approximately seven months. Seagrass cover significantly decreased after the plant started operating but showed partial recovery over time. These findings highlight the adverse effects of thermal pollution on seagrass ecosystems, emphasizing the need for effective management strategies to mitigate such impacts. This research contributes to the limited understanding of thermal pollution in marine protected areas, offering valuable insights for environmental monitoring and policy development.