High survival following bleaching underscores the resilience of a frequently disturbed region of the Great Barrier Reef

• DOI: 10.1002/ecs2.4280
• Publication Date: 2023-02-14T01:48:46Z
• Authors: Cathie A. Page; Christine Giuliano; Line K. Bay; Carly J. Randall
• Keywords: Acropora; Coral bleaching; Porites; Dominance (genetics); Symbiodinium

Abstract Natural bleaching events provide an opportunity to examine how local‐scale environmental variation influences severity and recovery. During the 2020 marine heat wave, we documented widespread severe coral affecting 75%–98% of cover throughout Keppel Islands in southern inshore Great Barrier Reef. Acropora , Pocillopora Porites were most severely affected genera, while Montipora was comparatively less susceptible. Site‐specific heat‐exposure metrics not correlated with severity, but recovery faster at sites that experienced lower exposure. Despite exposure accumulated often results mortality (degree heating weeks ~4–8), remained stable. Approximately 94% fate‐tracked millepora colonies survived, perhaps due reduced irradiance stress from high turbidity, heterotrophic feeding, large tidal flows can increase mass transfer. Severe followed by rapid continuing dominance populations is indicative resilience. These communities have survived a 0.8°C average temperatures over last 150 years. However, following driven easing thermal stress, which may challenge their potential under further warming.