The role of the microbiome on coral heat tolerance

Global warming presents an unprecedented challenge to one of the world’s most iconic ecosystems, coral reefs. Scleractinian (stony) corals, the primary architects of warm water reefs, are in steep decline due to rising ocean temperatures. The world’s most heat-tolerant corals are found in the Persian/Arabian Gulf (PAG) where they endure summer temperatures around 35°C for more than 2 months every year. Comparable levels of heat stress would kill conspecifics anywhere else (Hume et al, 2016). Notably, the PAG is a geologically young sea that has formed only ~12k years ago and the heat tolerant coral communities have established themselves within less than the last 4-7k years, making them ideal models to study adaptations to extreme temperature environments. Critically, coral heat tolerance needs to be understood in the context of a complex physiological response to local environmental parameters (D’Angelo et al 2015).

Stony corals are complex organisms characterised by the association of an animal host with symbiotic, photosynthetic dinoflagellates (zooxanthellae) and microbial communities. Collectively, this association is referred to as the “coral holobiont”. The breakdown of the symbiosis between the animal and zooxanthellae can lead to the phenomenon of mass “coral bleaching”, the discoloration of the animal host that results often in coral mortality and subsequent reef habitat degradation. The coral-associated microbiome has been proposed as a key contributor to the holobiont health and temperature tolerance. However, despite its potential significance, the role of the microbial communities in the extreme heat tolerant corals from the PAG is yet to be fully established (Bourne et al 2016).

This project aims to discern the effect of the microbial communities in the response of PAG corals to anomalous high temperature in combination with distinct environmental parameters that define their natural habitat. To this end, PAG corals will be exposed, under carefully controlled environmental conditions, to stressful levels of salinity and temperature. The microbiome structure will be characterised by 16S rDNA gene amplicon sequencing. Both targeted and meta-omics bioinformatic analyses will be used to identify the key microbial taxa and associated changes in their metabolic functions in response to the simulated changes in the water parameters.

Training

All doctoral candidates will enrol in the Graduate School of NOCS (GSNOCS), where they will receive specialist training in oral and written presentation skills, have the opportunity to participate in teaching activities, and have access to a full range of research and generic training opportunities. GSNOCS attracts students from all over the world and from all science and engineering backgrounds. There are currently around 170 full and part-time PhD students enrolled (~60% UK and 40% EU & overseas). 

Specific training will include:

Molecular techniques (including DNA extraction, PCR and Sequencing), Bioinformatic analyses (specialist software, sequence analysis). Aquaculture, coral husbandry, experimentation with live corals under controlled environmental conditions. The successful applicant will be embedded within the larger project funded by the Leverhulme Trust and will participate in scientific collaborative initiatives.