Pérez-Rosales et al. 2021

Mesophotic coral communities escape thermal coral bleaching in French Polynesia

Pérez-Rosales G, Rouzé H, Torda G, Bongaerts P, Pichon M, Under The Pole Consortium, Parravicini V, Hédouin L

scientific article R Soc Open Sci Open Access
Abstract

Climate change and consequent coral bleaching are causing the disappearance of reef-building corals worldwide. While bleaching episodes significantly impact shallow waters, little is known about their impact on mesophotic coral communities. We studied the prevalence of coral bleaching two to three months after a heat stress event, along an extreme depth range from 6 to 90 m in French Polynesia. Bayesian modelling showed a decreasing probability of bleaching of all coral genera over depth, with little to no bleaching observed at lower mesophotic depths (greater than or equal to 60 m). We found that depth-generalist corals benefit more from increasing depth than depth-specialists (corals with a narrow depth range). Our data suggest that the reduced prevalence of bleaching with depth, especially from shallow to upper mesophotic depths (40 m), had a stronger relation with the light-irradiance attenuation than temperature. While acknowledging the geographical and temporal variability of the role of mesophotic reefs as spatial refuges during thermal stress, we ought to understand why coral bleaching reduces with depth. Future studies should consider repeated monitoring and detailed ecophysiological and environmental data. Our study demonstrated how increasing depth may offer a level of protection and that lower mesophotic communities could escape the impacts of a thermal bleaching event.

Keywords
Metadata (pending validation)
Depth Range
6–90 m
Mesophotic Mentions
20 × (total of 4045 words)
Classification
  • Presents original data
  • Focused on 'mesophotic' depth range
  • Focused on 'mesophotic coral ecosystem'
Locations
French Polynesia
Platforms
Rebreather
Author Profiles