Background/Question/Methods
The benthic environments of coral reefs are shaped not only by physiochemical factors, but also by the ecological interactions of the animals and plants in the reef ecosystem. Microbial populations may be shared among the ecosystem of sediments, seagrasses and reef fish, however it is unknown to what degree these components draw from a common microbial pool. We investigated the potential connections between the microbiomes of sediments, seagrass blades and roots, the guts of herbivorous fish included both Surgeonfish (Acanthurus nigricauda, A. sp. , Ctenochaetus striatus) and Parrotfish (Calotomus spinidens) in reef areas of Fiji. We place these site-specific results in a broader biogeographic context by contrasted Fijian sediment diversity to sediment samples from reefs in the Florida Keys.
Results/Conclusions
We show connectivity of a core microbiome between seagrass, fish and sediments in Fiji, including identifying a potential environmental reservoir of a surgeonfish symbiont. We also show that fish guts have different microbial populations from crop to hindgut, and that microbial populations differ based on food source, yet there is a general homogenization of microbial gut fauna occurs across different host species. Finally our observed patterns in microbial diversity mirror those macro diversity patterns with a higher diversity of sediment microbial communities in Fiji compared to the Florida Keys. However, many of the same taxa are shared in these chemically similar environments. These diversity patterns suggest that reef organisms are connected through a shared microbial pool at the scale of individual reefs, but that individual taxa predominate according to the ecology of their hosts.