Algal Symbionts Indicate Heatwave Vulnerability in Corals From Hotspots but Not From Thermal Refugia.

ABSTRACT: Reef-building corals face continued declines due to climate change-amplified marine heatwaves. In addition to affecting coral heat tolerance, corals' algal endosymbionts (family Symbiodiniaceae) can reflect their prior heatwave exposure, although understanding is often limited to heatwave-induced shifts between symbiont genera. Here, we used ITS2 metabarcoding to characterise Symbiodiniaceae assemblages in 293 individuals of the common Indo-Pacific coral Acropora aff. digitifera in Palau (Western Pacific), between two outer-reef regions with contrasting heatwave histories. During the strongest recorded heatwaves, southwestern 'hotspot' reefs have typically accrued an additional 2°C-weeks of heat stress compared to thermal 'refugia' located 60 km north. In contrast to previous studies that

SUBMITTER: Buzzoni D 

PROVIDER: S-EPMC12811821 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature