Application of remotely sensed sea surface temperature for assessment of recurrent coral bleaching (2014–2019) impact on a marginal coral ecosystem

Abstract

The 2014–2016 El Niño Southern Oscillation (ENSO) caused a prolonged marine heatwave that led to widespread coral bleaching and mortality across the Indo-pacific coral reefs. Prediction of coral bleaching and assessment of bleaching impact on corals is vital for reef ecosystem functioning, services and management. Wherein, advanced satellite remote sensing approach to determine and quantify the thermal stress on corals can assist as an alternative and convenient tool for reef monitoring programs. The present study examines the impact of consecutive coral bleaching episodes on shallow-water marginalized patch reef ecosystems on the Eastern Arabian Sea. Advanced Very High-Resolution Radiometer (AVHRR) satellite data from the NOAA Coral Reef Watch’s (NOAA-CRW) platform, known as CoralTemp, were used to analyze the thermal stress on the coral reefs. Coral bleaching indices like Bleaching Threshold (BT), Positive Anomaly (PA), and Degree Heating Weeks (DHW) were calculated. Ground-truthing revealed that detected thermal stress from satellite-derived Sea Surface Temperature (SST) data over this region well corroborate with the mass coral bleaching events, and found reliable for detecting coral bleaching episodes in the marginalized turbid coral habitats. This study signifies the potential benefit of incorporating remote sensed SST data in coral bleaching monitoring program, which may guide to undertake targeted coral surveys and aid in decision-making and conservation of the vulnerable coral reef ecosystems.