Effect of Marine Heat Waves for Coral Bleaching in Lombok Waters
Achmad Nagi 1, Susanna Nurdjaman 2, Ivonne Milichristi Radjawanne 2,3, Gandhi Napitupulu 4, Ahmad Dhuha Habibullah 1, Hansan Park 3

1. Earth Science Study Program, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Jalan Ganesha 10, Kota Bandung, Jawa Barat, 40132 Indonesia

2. Oceanography Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Jalan Ganesha 10, Kota Bandung, Jawa Barat, 40132 Indonesia

3. Korea-Indonesia Marine Technology Cooperation Research Center, Bandung Institute of Technology, Jl. Kebonturi Arjawinangun, Kab. Cirebon, Jawa Barat, 45162 Indonesia

4. Oceanography Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung, Jl. Kebonturi Arjawinangun, Kab. Cirebon, Jawa Barat, 45162 Indonesia

Abstract

Extreme climate and weather events shape the structure of terrestrial biological systems and affect the biogeochemical functions and services they fundamentally provide for society. 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. Coral bleaching occurs when corals lose their symbiosis with zooxanthellae algae due to extreme environmental stress, such as rising sea surface temperatures (SST). 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. Notably, a substantial increase in SST results in coral disassociation with zooxanthellae algae, leading to a noticeable paling of coral color. Additionally, the research establishes a direct relationship between the duration and intensity of marine heat waves and coral bleaching rates. 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. From 2019 to 2022, there was another decline, although the area remains above the 10,000-hectare mark. 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, hu

Keywords: Coral bleaching, Lombok, Marine Heat Waves, Sea Surface Temperature

Topic: Ocean Remote Sensing and Marine Technology