Anna Roik

Reef-building corals are threatened by ocean warming and pollution that progress too rapidly for the long-lived organisms to genetically adapt. However, a new perspective of corals as ‘holobionts’ suggests that resilience could be conferred by the microbiome within one generation. Bacterial microbiome communities are highly diverse and dynamic. However, our understanding of their ecology and functions in corals is limited. I propose to study bacterial microbiomes of resilient corals and low-resilience conspecifics to know more of their drivers and functions, and explain their role in coral acclimatization and resilience. In the Andaman Sea, large-amplitude internal waves (LAIW) create highly variable habitats in terms of temperature and nutrients, giving rise to corals more heat tolerant compared to conspecifics from more stable habitats nearby. Corals will be surveyed across different habitat and resilience traits. Taxonomic profiling of bacterial communities alongside with high-resolution host genotyping will provide new insights into (1) hostmicrobe-environment relations and (2) microbiome specificity of coral resilience. The role of the microbiome in acclimatization will be addressed by an in situ time-series study of taxonomic and functional microbiome dynamics during the LAIW peak and low season (3). Lastly, stress-exposure experiments will show (4) to what extent taxonomic and functional changes in the microbiome can be linked to the physiological and transcriptomic host response of stress vs stress-tolerance. Increasing our knowledge of the coral microbiome will likely lead to novel restoration strategies using microbiome manipulation to help build coral resilience.