Résumé
Coral reefs host hundreds of thousands of animal species that are
increasingly threatened by anthropogenic disturbances. These animals host
microbial communities at their surface, playing crucial roles for their
fitness. However the diversity of such microbiomes is mostly described in
a few coral species, and still poorly defined in other invertebrates and
vertebrates. Given the diversity of animal microbiomes, and the diversity
of host species inhabiting coral reefs, the contribution of such
microbiomes to the total microbial diversity of coral reefs could be
important, yet potentially vulnerable to the loss of animal species.
Analysis of the surface microbiome from 74 taxa, including teleost fishes,
hard and soft corals, crustaceans, echinoderms, bivalves and sponges,
revealed that more than 90% of their prokaryotic phylogenetic diversity
was specific and not recovered in surrounding plankton. Estimate of the
total diversity associated to coral reef animal surface microbiomes
reached up to 2.5% of current estimates of Earth prokaryotic diversity.
Therefore, coral reef animal surfaces should be recognized as a hotspot of
marine microbial diversity. Loss of the most vulnerable reef animals
expected under present-day scenarios of reef degradation would induce an
erosion of 28% of the prokaryotic richness, with unknown consequences on
coral reef ecosystem functioning.