Coral reefs are among the most biodiverse marine ecosystems on the planet, and provide substantial economic and ecological benefits to coastal communities. Corals are composed of both the Cnidarian animal host and complex communities of unique and underexplored microbial organisms. Today these natural wonders are in global decline, threatened by the intersecting effects of multiple stressors including overfishing, pollution, and climate change. These stressors can alter coral microbial communities in ways that may make corals more susceptible to disease or algal competition. Therefore understanding the relationships between corals and their microbiota may be useful for efforts to combat coral disease and preserve reef ecosystems. While much effort is underway to understand coral reef ecosystems and help steward them for future generations, most studies of the microbial communities present on corals have focused on a relatively small portion of coral diversity, in terms of both the locations in which it has been studied and the evolutionary linages of the corals. As a result the microbial diversity of coral species in many diverse and ancient groups remains unexplored, but understanding these communities will help to extend the knowledge gained in well-studied corals to diverse reefs worldwide. This project therefore aims to describe microbial diversity across all major groups of reef-building corals in each of several distinct ecosystems across the globe, to determine the genome sequences and metabolic capabilities of key coral bacteria, and to test whether the composition of coral microbial communities helps to explain the overall vulnerability or resistance of different coral species to stress or disease.
Coral species differ in their susceptibility to bleaching and disease, but these differences are only partially explained by coral phylogeny. Therefore this project will test the extent to which incorporating the microbiota (or their contributed genes) better predicts these and other traits. Recent technological advances will allow us to examine the role of more complex microbiomes in shaping the life history, physiology, and evolution of their multicellular hosts (e.g., the human microbiome). The use of newly developed DNA sequencing techniques will allow a more complete exploration of microbial diversity than has previously been feasible, while advanced computational methods will help to maximize the value of sequenced bacterial genomes. Improved predictive models that incorporate both coral phylogeny and microbial function will help us inform conservation strategies and yield predictive biomarkers for coral vulnerability to disease or bleaching. Relating the diversity of corals to the diversity of their microbes will also provide important insights into how intimate symbiotic associations with microorganisms arose and are maintained in diverse animals- including us.
Timely updates will be posted on Ryan's blog, the Cnidae Gritty. We have also been collaborating with the marketing department at Oregon State University to produce professional articles, videos, and other media. So far, we have been featured in Terra Magazine, Beavernation.is, and previews for a feature film Saving Atlantis.
Sequence data, sample metadata, raw photos, and other files will be available as soon as possible on our server. Some preliminary 16S and Symbiodinium ITS2 data from our first expeditions in Australia are already available.
Processed photos of our corals are on Flickr, where you can use keywords such as taxonomy (try 'Acropora palmata', 'Fungiidae', or 'Clade XVII') or location ('KAUST', 'Australia', etc.) to narrow the list. Nobody's perfect at coral taxonomy, so let us know if we can improve our coral IDs! We have tagged corals that we're unsure of with the keyword 'Taxonomy uncertain'.
Joe gave a great talk about our preliminary results at ICRS, which you can watch here: