Despite being one of the simplest metazoans, corals harbor some of the most highly diverse and abundant microbial communities. Differentiating core, symbiotic bacteria from this diverse host-associated consortium is essential for characterizing the functional contributions of bacteria but has not been possible yet. Here we characterize the coral core microbiome and demonstrate clear phylogenetic and functional divisions between the micro-scale, niche habitats within the coral host. In doing so, we discover seven distinct bacterial phylotypes that are universal to the core microbiome of coral species, separated by thousands of kilometres of oceans. The two most abundant phylotypes are co-localized specifically with the corals’ endosymbiotic algae and symbiont-containing host cells. These bacterial symbioses likely facilitate the success of the dinoflagellate endosymbiosis with corals in diverse environmental regimes.

Depth range
1- 123 m

Mesophotic “mentions”
4 x (total of 5911 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'

Fields
Biodiversity
Ecology
Molecular ecology

Focusgroups
Scleractinia (Hard Corals)
Bacteria and Archaea

Locations
Australia - Coral Sea
Australia - Great Barrier Reef
USA - Hawaii

Platforms
SCUBA (open-circuit or unspecified)
Rebreather
Manned Submersible