TY - JOUR
T1 - The 2022 summer marine heatwaves and coral bleaching in China's Greater Bay Area
AU - Zhao, Yu
AU - Chen, Mingru
AU - Chung, Tzu Hao
AU - Chan, Leo Lai
AU - Qiu, Jian Wen
N1 - This project was supported by Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) ( L2019005 , GML2019ZD0404 ) and Lantau Conservation Fund ( RE-2020-22 ).
Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2023/7
Y1 - 2023/7
N2 - From July to August 2022, scleractinian coral communities in China's Greater Bay Area (GBA) in the northern South China Sea (nSCS) experienced an unprecedented bleaching event, despite the fact that coral communities in this area are often considered coral thermal refugia due to their high latitude distribution. Field surveys of six sites covering three main coral distribution areas of the GBA revealed that coral bleaching occurred at all sites. Bleaching was more severe in shallow water (1–3 m) than in deep water (4–6 m), as indicated by both percent bleached cover (51.80 ± 10.04% vs. 7.09 ± 7.37%) and bleached colonies (45.86 ± 11.22% vs. 6.58 ± 6.53%). Coral genera Acropora, Favites, Montipora, Platygyra, Pocillopora, and Porites showed high susceptibility to bleaching, and Acropora and Pocillopora suffered high post-bleaching mortality. In the three areas surveyed, analysis of oceanographic data detected marine heatwaves (MHWs) during the summer, with mean intensities between 1.62 and 1.97 °C and durations between 5 and 22 days. These MHWs were primarily driven by increased shortwave radiation due to strong western Pacific Subtropical High (WPSH), combined with reduced mixing between the surface and deep upwelling waters due to reduced wind speed. Comparing with histological oceanographic data showed that the 2022 MHWs were unprecedented, and there was a significant increase in the frequency, intensity, and total days of MHWs during 1982–2022. Furthermore, the heterogeneous distribution of summer MHW characteristics indicates that the coastal upwelling may modulate the spatial distribution of summer MHWs in nSCS through its cooling effect. Overall, our study indicates that MHWs may have affected the structure of the subtropical coral communities in the nSCS, and impaired their potential as thermal refugia.
AB - From July to August 2022, scleractinian coral communities in China's Greater Bay Area (GBA) in the northern South China Sea (nSCS) experienced an unprecedented bleaching event, despite the fact that coral communities in this area are often considered coral thermal refugia due to their high latitude distribution. Field surveys of six sites covering three main coral distribution areas of the GBA revealed that coral bleaching occurred at all sites. Bleaching was more severe in shallow water (1–3 m) than in deep water (4–6 m), as indicated by both percent bleached cover (51.80 ± 10.04% vs. 7.09 ± 7.37%) and bleached colonies (45.86 ± 11.22% vs. 6.58 ± 6.53%). Coral genera Acropora, Favites, Montipora, Platygyra, Pocillopora, and Porites showed high susceptibility to bleaching, and Acropora and Pocillopora suffered high post-bleaching mortality. In the three areas surveyed, analysis of oceanographic data detected marine heatwaves (MHWs) during the summer, with mean intensities between 1.62 and 1.97 °C and durations between 5 and 22 days. These MHWs were primarily driven by increased shortwave radiation due to strong western Pacific Subtropical High (WPSH), combined with reduced mixing between the surface and deep upwelling waters due to reduced wind speed. Comparing with histological oceanographic data showed that the 2022 MHWs were unprecedented, and there was a significant increase in the frequency, intensity, and total days of MHWs during 1982–2022. Furthermore, the heterogeneous distribution of summer MHW characteristics indicates that the coastal upwelling may modulate the spatial distribution of summer MHWs in nSCS through its cooling effect. Overall, our study indicates that MHWs may have affected the structure of the subtropical coral communities in the nSCS, and impaired their potential as thermal refugia.
KW - Climate change
KW - Coastal waters
KW - Greater Bay Area
KW - High-latitude reef
KW - Marginal coral reef
KW - Upwelling
KW - Western pacific subtropical high
UR - http://www.scopus.com/inward/record.url?scp=85162179604&partnerID=8YFLogxK
U2 - 10.1016/j.marenvres.2023.106044
DO - 10.1016/j.marenvres.2023.106044
M3 - Journal article
C2 - 37321888
AN - SCOPUS:85162179604
SN - 0141-1136
VL - 189
JO - Marine Environmental Research
JF - Marine Environmental Research
M1 - 106044
ER -