Coral bleaching due to cold stress on a central Red Sea reef flat

Ocean warming is leading to more frequent coral bleaching events. However, cold stress can also induce bleaching in corals. Here, we report observations of a boreal winter bleaching event in Jan 2020 in the central Red Sea, mainly within a population of the branching coral Stylophora pistillata on an offshore reef flat. Sea surface temperatures rarely fall below 24°C in this region, but data loggers deployed on several nearby reef flats recorded overnight seawater temperatures as low as 18°C just three days before the observations. The low temperatures coincided with an extremely low tide and cool air temperatures, likely resulting in the aerial exposure of the corals during the nighttime low tide event. The risk of aerial exposure is rare in winter months, as the Red Sea exhibits seasonal fluctuations in sea level with winter values typically 0.3-0.4m higher than in summer. These observations are notable for a region typically characterized as a high-temperature sea, and highlight the ...

海洋变暖正导致珊瑚白化事件愈发频发。然而，低温胁迫同样可诱发珊瑚白化。本研究报道了2020年1月红海中部的一次冬季珊瑚白化观测结果，该事件主要发生在离岸礁坪上的分枝型皮氏杯形珊瑚（Stylophora pistillata）种群中。该区域海域表层水温通常极少低于24℃，但在本次观测前三天，部署于附近多处礁坪的水温数据记录仪记录到夜间海水温度低至18℃。此次低温过程与极端低潮及低温大气条件同步发生，大概率使得珊瑚在夜间低潮时段暴露于空气中。由于红海海平面存在季节性波动，冬季海平面通常较夏季高出0.3-0.4米，因此冬季出现珊瑚空气暴露的风险极低。上述观测结果对于这片通常被定义为高温海域的区域而言具有重要研究价值，且凸显了……