Early Life Stages of a Common Broadcast Spawning Coral Associate with Specific Bacterial Communities Despite Lack of Internalized Bacteria

Abstract

Coral-associated bacteria are critical for the well-being of their host and may play essential roles during ontogeny, as suggested by the vertical transmission of some bacteria in brooding corals. Bacterial acquisition patterns in broadcast spawners remain uncertain, as 16S rRNA gene metabarcoding of coral early life stages suggests the presence of bacterial communities, which have not been detected by microscopic examinations. Here, we combined 16S rRNA gene metabarcoding with fluorescence in situ hybridization (FISH) microscopy to analyze bacterial assemblages in Acropora tenuis egg–sperm bundles, embryos, and larvae following a spawning event. Metabarcoding results indicated that A. tenui..