| Caribbean acroporid corals suffered region-wide declines during the past two decades, prompting their recent listing as 'threatened species'. A diverse microbiota associated with these corals is thought to participate in coral health and disease processes. This project identified microbial associates of acroporid corals along the length of the Florida reef tract during 2003 and investigated the influence of location, coral species, temporality, sample processing methodology, and health status on resulting community profiles.;Sample type (mucus, tissue or tissue/skeleton) and processing method introduced significant variability in community profiles. Coral mucus however, produced consistent community structures using clone library sequencing methodologies. Healthy coral mucus had largely consistent microbial community structure across the study area and among acroporid species. The microbiota of healthy corals sampled in late spring was dominated by Pseudomonadaceae and Xanthomonadaceae (at a predictable ratio). Corals sampled six weeks later lacked this association and hosted more diverse assemblages, indicating a consistent restructuring of the microbial communities over this time period.;Similar mortalities of acroporids occurred throughout southern Florida during 2003. Primers designed to detect previously noted coral pathogens, revealed no consistent associations with diseased corals. Microbial communities of corals exhibiting disease signs in the northern Florida Keys had unique microbial profiles as compared to healthy, with increased occurrence of Flavobacteriaceae, Vibrio spp., and Photobacterium spp. Diseased corals from the Dry Tortugas were not significantly different from reference corals. These data and histologic examination support a unique pathology in that population of corals. A key histologic distinction was an increase in intertissue bacterial aggregates (BA). Laser capture microdissected BA were notably enriched in a Pseudomonas mendocina-like bacterium (350% increase over control).;This work required the most extensive coral 16S rDNA sequencing to date (>25,000 sequences examined from cultured and uncultured microbes inhabiting the coral mucus, tissues, skeleton, and the surrounding water column). The complexity of these data sets (69 libraries matrixed over time, space, species, and health condition) necessitated novel bioinformatic data analysis approaches, including the adaptation of heat map analysis, allowing for simultaneous compositional comparison of multiple bacterial populations. |
