Suspended Matter And Chlorophyll-a Dynamics Along The Coasts of Western Java and Banten

Oil spills are recurring hazards for tropical coastal ecosystems, yet their ecological impacts remain insufficiently understood in monsoon-dominated waters such as northern Java, Indonesia. Two large spills in Karawang (July 2019 and April 2021) provided a natural experiment to evaluate how suspended matter and phytoplankton respond to acute disturbances under contrasting seasonal conditions. Unlike earlier studies focusing on single incidents, this work integrates multiple parameters and events to reveal long-term ecosystem trajectories. We analyzed satellite-derived datasets from 2019–2023, including Sentinel-3 OLCI Total Suspended Matter (TSM) and Suspended Particulate Matter (SPM), Aqua-MODIS Chlorophyll-a (Chl-a), ERA5 winds, and NOAA OISST sea surface temperatures. Spatial anomalies, seasonal climatologies, and site-specific time-series at Lontar, Karawang, and Cirebon were combined with linear trend analyses to separate natural variability from anthropogenic disturbance. Both spill events caused sharp increases in TSM and SPM, with July 2019 producing broader anomalies due to east monsoon transport, while April 2021 impacts were more localized. Chl-a anomalies dropped most strongly at Karawang, indicating phytoplankton suppression from turbidity and hydrocarbon stress, with weaker declines west and east. Over 2019–2023, suspended matter showed significant decreases while Chl-a trended upward, suggesting clearer waters enhanced light penetration and supported partial biological recovery. These findings demonstrate that optical recovery is faster than ecological recovery, with oil spill legacies persisting unevenly across northern Java’s coastal waters.