Involved Members: Dr. Leo Lai CHAN, Prof. Jianwen QIU

Coral communities in China’s Greater Bay Area (GBA) experienced an unprecedented coral bleaching event in the scleractinian coral communities located in the northern South China Sea (nSCS) from July to August 2022. This research conducted field surveys at 6 sites in the three main coral distribution areas of the GBA. The results indicate that coral bleaching was observed at all sites, with the bleaching being more severe in the shallow waters (1-3 meters) compared to the deeper waters (4-6 meters). By analysing oceanographic data, marine heatwaves (MHWs) were detected during the summer in 3 of the surveyed areas, with mean intensities between 1.62 and 1.97°C and durations between 5 and 22 days. Histological oceanographic data further suggested a significant increase in the frequency, intensity, and total days of MHWs in 2022 compared to previous years. This impacted the structure of subtropical coral communities in the nSCS and weakened their potential as thermal refugia.

Reference:
Zhao, Y., Chen, M., Chung, T.H., Chan, L.L., Qiu, J.W., (2023). The 2022 summer marine heatwaves and coral bleaching in China's Greater Bay Area. Marine Environmental Research, 189, 106044. (impact factor: 3.737)