Award: OCE-1928753

Coral disease is a significant and increasing threat to Caribbean coral reef ecosystems. Stony coral tissue loss disease (SCTLD) is a recently emergent coral disease that affects multiple species of Caribbean corals. This disease is considered among the most devastating coral diseases ever recorded due to its wide range of host species, high mortality rates, and unrelenting spread. In early 2019, a multi-species rapid tissue loss disease with signs and species susceptibility characteristics matching those described for SCTLD was found severely affecting a reef off the southwest coast of St. Thomas in the United States Virgin Islands. Rapid surveys by our group determined the initial incidence area of the disease to be limited to a 50 km2 area southwest of St. Thomas. This project conducted further work that was coordinated with local governmental and conservation groups to track the disease as it spread throughout the entire U.S. Virgin Islands territory. The onset of the epizootic offered the unprecedented opportunity to test hypotheses about the impact of species susceptibility on disease spread and impact during the early stages of an outbreak. We performed experiments to directly compare species physiological responses to disease exposure and test the effect of species assemblage on disease spread. Our results documented differences in disease incidence, lesion expansion, and mortality among species, and identified microbial signatures of disease that related to susceptibility. Our results also demonstrated that general disease spread was driven by dominant ocean currents, but that coral community composition mattered such that greater species diversity was associated with higher disease prevalence as well as greater losses due to disease. Overall, our project resulted in seven peer-reviewed publications, including the publication of genomic resources for use by the SCTLD field in identifying potential pathogens, and more publications are in development. This project brought together students and researchers from six different institutions, including from five women-led laboratories, which resulted in an abundant collection of opportunities for cross-training and multi-level mentoring. In addition, a graduate-student led capstone project provided a significant published contribution to project results, and the experience provided research and manuscript-development training for a whole cohort of Masters of Science students at the University of the Virgin Islands, an Historically Black University. Broader impact outcomes also included one masters student graduating and going on to a PhD program at Pennsylvania State University, and one masters student graduating and becoming a biological technician who continues to work on SCTLD issues in the U.S. Virgin Islands. One black Virgin Islander undergraduate research assistant went on to receive an NSF GRFP and began in a PhD program at Texas A&M University. Project personnel and students contributed to multiple U.S. Virgin Islands-local, national, and international presentations, many of which were virtually delivered during the pandemic. A highlight was a virtual seminar by PI?s M. Brandt and A. Apprill who were joined by legendary oceanographer Dr. Sylvia Earle. Project personnel at the University of the Virgin Islands also led the development of a website, vicoraldisease.org, that provides regularly updated disease tracking and intervention information and resources for the U.S. Virgin Islands. Last Modified: 09/09/2022 Submitted by: Marilyn Brandt