Mo Shaohua, Chen Tianran, Chen Zesheng, Zhang Wenjing, Li Shu
Beihai Marine Environmental Monitoring Center Station, State Oceanic Administration, Beihai 536000, China.
Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
Sci Total Environ. 2022 Jun 15;825:154100. doi: 10.1016/j.scitotenv.2022.154100. Epub 2022 Feb 24.
Frequent marine heatwaves (MHWs), concurrent with climate warming, threaten global low-latitude, pristine coral reefs, leading to growing interest in identifying marginal coral reefs (relatively high-latitude and/or turbid reef environments) that can serve as thermal refugia from mass coral bleaching. However, the thermal refugia potential of marginal reefs remains controversial. We evaluated the thermal refugia potential of inshore reefs in the northern South China Sea (nSCS), a globally typical marginal reef system, by characterizing the long-term trend of MHW intensity and frequency and assessing thermal stress during a mass bleaching event in summer 2020. An unprecedented peak intensity of around 20 °C-weeks of cumulative heat stress, associated with a prolonged anomalous western Pacific subtropical high (WPSH) and weakened monsoon activity, induced record-breaking bleaching. The geographical variability of bleaching was strongly related to the extent of heat exposure and satellite-derived temperature anomalies. Under ongoing global warming, the frequency and intensity of MHWs over nSCS coral habitats show a markedly increasing trend, especially during the last decade. Intense MHWs and coral bleaching have already occurred throughout all El Niño-Southern Oscillation (ENSO) phases (e.g., 2010, 2015, and 2020). Climate change has pushed marginal coral reefs to or beyond the limits of their resilience, and frequent MHW events have amplified the increasing risk of thermal stress. There are no long-term thermal refugia for marginal reefs in the nSCS.
频繁出现的海洋热浪（MHWs），与气候变暖同时发生，威胁着全球低纬度的原始珊瑚礁，这使得人们越来越有兴趣去识别那些可以作为抵御大规模珊瑚白化热避难所的边缘珊瑚礁（相对高纬度和/或浑浊的珊瑚礁环境）。然而，边缘珊瑚礁的热避难所潜力仍存在争议。我们通过刻画海洋热浪强度和频率的长期趋势，并评估2020年夏季一次大规模白化事件期间的热应激，来评估南海北部（nSCS）近岸珊瑚礁的热避难所潜力，南海北部是全球典型的边缘珊瑚礁系统。与西太平洋副热带高压（WPSH）长期异常和季风活动减弱相关的约20℃-周的累积热应激前所未有的峰值强度，引发了破纪录的珊瑚白化。白化的地理变异性与热暴露程度和卫星反演的温度异常密切相关。在全球持续变暖的情况下，南海北部珊瑚栖息地的海洋热浪频率和强度呈现出明显增加的趋势，尤其是在过去十年间。强烈的海洋热浪和珊瑚白化在所有厄尔尼诺-南方涛动（ENSO）阶段（如2010年、2015年和2020年）均已发生。气候变化已将边缘珊瑚礁推向或超出其恢复力的极限，频繁的海洋热浪事件加剧了热应激风险的上升。南海北部的边缘珊瑚礁不存在长期的热避难所。
