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 January 2020 in the central Red Sea, mainly within a population of the branching coral Stylophora pistillata on an offshore reef flat. Sea surface temperatures (SSTs) 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 3 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 night time 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 0.3–0.4 m higher than in summer. These observations are notable for a region typically characterized as a high-temperature sea, and highlight the need for long-term monitoring programs as this rare event may have gone unnoticed.
Bibliographical noteFunding Information:
We thank the King Abdullah University of Science and Technology (KAUST) Coastal and Marine Resources Core Lab for providing the tidal data and support for fieldwork. We thank Ute Langner for creating the map in Figure 1 . Funding for this study was provided by KAUST (baseline funds to MLB).
© 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
- aerial exposure
- cold stress
- Stylophora pistillata
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Nature and Landscape Conservation