A global view of the biocomplexity underlying coral holobiont health and climate change resilience

• Applicant: Professor Dr. Christian Voolstra, Ph.D.
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions ; General Genetics and Functional Genome Biology ; Microbial Ecology and Applied Microbiology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 458901010

Productivity and biodiversity of coral reef ecosystems depend on healthy corals, sessile cnidarians of the class Anthozoa that engage in symbioses with microalgae of the family Symbiodiniaceae and a suite of other microbes (bacteria, archaea, etc.) that all contribute critically to the resilience and functioning of the emerging coral metaorganism or holobiont. This notion necessitates that one must examine the biocomplexity of the coral holobiont (i.e., the interplay between metaorganism biodiversity, ecological function, and the emergent phenotype) to better understand how identity and functional diversity of associated microbes contribute to the health and resilience of coral metaorganisms. However, at present, we lack an integrative understanding of how holobiont diversity and the implied functional differences scale over geographical and environmental regimes, and how this in turn affects coral metaorganism phenotypes. Here we aim to build an analytical framework that integrates holobiont biodiversity, stress tolerance, and environmental setting to elucidate coral holobiont ‘configurations’ that are representative/predictive of metaorganism resilience. We propose to do this through collection of environmental parameters and the recording of heat stress phenotypes of four common coral species across four major coral reef regions (the Central Pacific Ocean, the Caribbean, the Arabian Seas, and the Coral Sea) with subsequent molecular elucidation of the underlying coral holobiont biodiversity through marker gene and metagenomic sequencing. Integrative analysis and modeling with these data will allow us to derive a global view of the links between coral holobiont composition, ecological success, and stress resilience. Such transdisciplinary and broad geographical approaches are rare, but fundamental to understand how holobiont diversity and environmental complexity shape patterns of species resilience. In addition, elucidation of metaorganism ‘signatures’, e.g. the presence of specific organismal entities, genotypes, or genes that are indicative of holobiont phenotypes, provides a critical building block to develop conservation/restoration strategies and predictive models about the future of coral reefs and the sites where coral reefs have a future. It will also allow for follow-up studies testing detailed mechanistic and functional aspects of animal-microbe associations. Insights from the here-proposed research will inform biology at large, e.g. on the compositional/functional landscape of metaorganisms across environments and how this affects metaorganism health and resilience, a topic of direct relevance to human well-being under climate change.

• DFG Programme: Research Grants