Effect of Marine Heat Waves for Coral Bleaching in Lombok Waters

Abstract

Abstract Coral reefs are fragile and endangered ecosystems in the tropical marine and coastal environment. Thermal stress induced by marine heatwaves (MHWs) can significantly harm coral health, leading to bleaching of the coral ecosystem. This study aims to quantify coral bleaching intensity in the Lombok region over recent decades, by analyzing MHWs intensity data derived from satellite-measured SST. In 1998, the coral reef area reached its peak with 36,550.71 ha. There was a sharp decline in 1999, reaching the lowest point at 4,865.76 ha. A significant increase was observed until a new peak in 2018 with 23,120.19 ha. The Western region experienced a significant increase from 1998 to 2018, followed by a decline. The Eastern Region showed significant fluctuations but generally trended upwards until 2018, followed by a sharp decline in 2019-2022. The Southern Region also experienced fluctuations, with an increase until 2018, followed by a significant decrease until 2022. The Northern Region showed a stable trend until 2016, then experienced a significant decline in 2017, and increased again in 2018. However, in subsequent years, the coral reef area in the Northern region remained relatively stable. Factors such as changes in sea surface temperature, human activities (e.g., overfishing or pollution), and climate change may have contributed to these fluctuations in the coral reef area on Lombok Island.