Tracking Bacterial, Viral, and Gene Expression Shifts throughout SCTLD Development in the Dry Tortugas

The rapid spread of SCTLD throughout Florida’s Coral Reef has hampered efforts to identify the causative pathogen, due in part to the difficulty of finding disease-susceptible corals with no prior disease exposure. This project leveraged integrative multi-omic and histological analyses to characterize SCTLD pathogenesis and coral immunity in four species of coral collected from Dry Tortugas National Park before and after the arrival of SCTLD. Histopathology of samples from this study showed consistent patterns to other histological analyses of SCTLD, although healthy samples from the Dry Tortugas exhibited an unusual amount of exocytosis. Initial analyses of coral microbial function and taxonomy based on shotgun sequencing data suggest that while microbial communities of corals naïve to SCTLD in Dry Tortugas National Park may differ from other corals sampled in the Florida Keys, microbial community function and composition of diseased samples from this study were similar to samples that have been previously sequenced. We found that diseased coral samples across coral species harbored viruses hypothesized to interact with the algal symbiont and viruses (including herpesvirus) that may influence host immunity capacity against other infections. Immune function in samples of healthy coral varied by species and patterns of change in function followed observed patterns of disease prevalence by month. Continued analyses supported by Florida DEP will focus on the development of robust, integrative analytical approaches to leverage the true power of this data set.