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Yellow band disease (YBD) is a common and wide-spread Caribbean syndrome that affects the genus Orbicella, a group of species that constitute the framework of Caribbean coral reefs. Previous studies have shown that the structure and function of bacterial assemblages vary between healthy tissues and YBD lesions; however, how the molecular composition of tissues varies as tissues transition from healthy to YBD has not been determined before. The present study provides the first survey of macromolecules found from healthy (H), apparently healthy (AH), transition (TR) and YBD tissues of Orbicella faveolata. For this, we used Fourier-transformed mid-infrared spectroscopy (FTIR) to compare absorption profiles as a proxy for the gross molecular composition of decalcified H, AH and YBD tissues. We found a significantly higher level of infrared absorption for bands assigned to lipids in H tissues compared to YBD tissues, suggesting that lipid compounds are more abundant in compromised tissues in relation to other macromole- cules. We also found a lower level of intensity of bands assigned to carbohydrates and proteins in YBD tissues, compared to H and AH tissues. A similar pattern was observed for phospholipidic compounds in relation to fatty acids. This study is the first to show that healthy and YBD-compro- mised tissues have different infrared absorption profiles, suggesting that alterations in the bio- chemical composition occur during pathogenesis. Future studies should focus on determining the actual concentration of these compounds in H, AH, TR and YBD tissues and on testing the role of translocation of photoassimilates from H tissues and/or from endolithic algae to YBD tissues.

The bacterial 16S rRNA gene diversity of waterborne bacterial (WBB) communities was assessed using PCR/denaturing gradient gel electrophoresis (DGGE) techniques, along with sequence analysis of selected bands. 16S rRNA gene diversity varied between seasons, and significant differences were recorded between night and day. However, there were no significant differences detected between low, ebb, flood and high tides when the water body sampled would have originated from completely different areas including those off-reef. These results suggest that changes in productivity and/or vertical diurnal migrations of plankton may have greater effects than large-scale water movements effected by tidal flows. These results do not demonstrate a strong link between WBB communities and their underlying benthos. This either suggests a lack of coupling between the benthos and the water column (benthic-pelagic coupling) or that the processes are extremely rapid and efficient with strong mixing. Previous studies at this site have shown cycling between coral reef and lagoon sediments via coral mucus release and tidal transport, supporting the latter. We found a strong seasonality in the abundance and composition of WBB communities, with Alphaproteobacteria being more prevalent during winter and Gammaproteobacteria during summer, but quantitative PCR (qPCR) showed no significant differences in vibrios between seasons.

Geographic assessments of coral diseases are needed to understand their local and geographic spatial-temporal variability. Coral and octocoral diseases and their prevalence were assessed along 4 permanent 10 x 2 m band-transects in each of 3 depth habitats (4, 5-12 and15 m) in each of 2 reefs in each of 6 countries across the wider Caribbean during the summer and fall of 2005. A permutational multivariate analysis of variance was used to test variability of major diseases and community level disease prevalence in corals and octocorals among habitats, reefs and countries. The most common and damaging diseases reported for the region were found in most reefs surveyed, but prevalence at the community level was generally low (ca. 2%) increasing from northern to southern latitudes. A significant interaction between sites (nested within country) and depth habitats was found (F = 2.1, df = 12, p = 0.02), with higher prevalence of coral diseases in deep habitats of Culebrita, Puerto Rico (14.8 +/- SE 6.5%) and in shallow habitats of Roldán, Panama (10.2 +/- SE 3.5%). The relative importance of each particular disease was dependent on site and habitat (depth intervals) (F = 1.7, df = 12, p = 0.001), with black band disease more prevalent in shallow habitats of Rita's, Bermuda (1.7 +/- SE 0.4%) and yellow band disease (YBD) more prevalent in deeper habitats of Chub Cut, Bermuda (3.7 +/- SE 0.5%). There was a significant interaction of total octocoral diseases with country and habitat (F = 2.8, df = 10, p = 0.04) with higher prevalence in deeper habitats of Curaçao (25.9 +/- SE 4.2%). Our results indicate that patterns of prevalence of coral and octocoral diseases were not consistent across the different spatial scales, showing differences produced by particular diseases and community composition present. There were no widespread epizootics, but local white plague-II and YBD epizootics were observed in Puerto Rico and other localities.

Geographic assessments of coral/octocoral diseases affecting major reef-building genera and abundant reef species are important to understand their local and geographic spatial-temporal variability and their impact. The status and spatial variability of major Caribbean coral/octocoral diseases affecting important reef-building coral (Montastraea, Diploria, Siderastrea, Stephanocoenia, Porites, and Agaricia) and common, widespread octocoral genera (Gorgonia and Pseudopterogorgia) was assessed along 4 permanent 10 x 2 m band-transects in each of 3 depth habitats (4, 5-12 and15 m) on 2 reefs in 6 countries across the wider Caribbean during the summer and fall of 2005. A permutational multivariate analysis of variance was used to test the spatial variability (countries, reef sites and depth habitats) in prevalence of major diseases in these genera. We found a significant interaction of disease prevalence in the different coral and octocoral genera between reef sites and habitats (depth intervals). Montastraea was primarily affected by both white plague (WP-II) and yellow band disease in deep (16.9 +/- SE 16% and 16.9 +/- SE 2.3%) and intermediate (8.1 +/- SE 1.6% and 15.5 +/- SE 2.3%) depth habitats of Culebrita (Puerto Rico) and Chub Cut (Bermuda), respectively. Prevalence of multiple diseases simultaneously and other compromised-health problems affecting Montastraea colonies varied between 0.2 to 2% and 0.2 to 1.8%, respectively. Agaricia and Diploria were mostly affected by WP-II (0.5 to 16%), black band disease (0.4 to 5%) and Caribbean ciliate infections (0.2 to 12%). Siderastrea and Stephanocoenia were mainly affected by dark spots disease in Curaçao, with higher prevalence in intermediate (40.5 +/- SE 6.2%) and deep (26.6 +/- SE 4.2%) habitats. Aspergillosis and other compromised-health conditions affected Gorgonia ventalina (0.2 to 8%) and other common and widespread octocoral genera (1 to 14%), respectively.

This is the first report of a putative pathogenic ciliate protozoan that has been associated with Caribbean corals. Previously, only 2 species of the phylum Ciliophora had been linked to coral diseases, and they were exclusive to the Indo-Pacific region. In this study, a ciliate of the genus Halofolliculina was found on 10 hard coral species at the National Parks of Los Roques and Morrocoy, Venezuela. The general morphology of this ciliate is very similar to that of Halofolliculina corallasia from the Indo-Pacific, which is known to cause skeletal eroding band. None of the other 31 genera in the family Folliculinidae are known to cause diseases in corals or in any other animal species. The presence of this ciliate, which shows a prevalence comparable to that of other epizootics in the Caribbean, suggests it could be a new threat to the coral reefs of this region.