Transcriptomic sequencing of four coral species in various stages of SCTLD development

Dry Tortugas National Park is separated from the Lower Keys by 70 miles, and has minimal impacts from anthropogenic stressors compared to other areas of Floridas Coral Reef. SCTLD was first observed in the outer margins of Dry Tortugas National Park in May 2021. In September 2021, researchers from Mote Marine Laboratory sampled 36 colonies at three sites in Loggerhead Forest and returned to these same colonies as SCTLD developed. Corals of four species: Montastraea cavernosa, Orbicella franksi, Orbicella faveolata, and Colpophyllia natans collected from the Dry Tortugas National Park. Three sites within Loggerhead Reef were each sampled before SCTLD reached the site and at two points during the initial outbreak, when sitewide disease prevalence was approximately 25 percent and 50 percent. By sampling colonies of four coral species throughout disease progression, we will capture shifts in both microbiome and virome composition and function in response to disease development within a single colony, potentially helping identify a causative pathogen/pathogen. We also assessed coral host response to disease development, which will help inform future approaches to increase coral immunity to SCTLD and related diseases.