Tropical reefs are hotspots of biodiversity and provide coastal protection and food security to seaside communities worldwide. Corals are the foundation species of most tropical reefs, providing structural habitat and food to the populations of animals and plants that reside there. In recent years, corals reefs have increasingly suffered significant habitat loss and ecosystem degradation with coral disease being a major contributor to this decline. In the past most scientific research has focused on bacterial or fungal diseases of corals. This project, however, explored and evaluated the viruses associated with tropical corals in order to better determine how they affect coral development, health, and disease. This project also aimed to better understand how environmental factors such as climate change, pollution, overfishing, and hurricanes induce viral production in these important ecosystems. Using funds from this NSF grant we used molecular and microscopy techniques, next generation sequencing, and computational analyses to evaluate the viral composition of a diversity of coral species from Hawaii, the Atlantic, Gulf of Mexico, South Pacific, and Great Barrier Reef. We also compared the viral types present in healthy and diseased corals. As a result of these efforts, we have discovered several unique groups of viruses. For example, we have found a new group of viruses called small circular single-stranded DNA viruses (SCSDVs) that may be the culprits behind a group of common coral diseases called æwhite plagues.Æ We also have discovered two types of viruses (a nucleocytoplasmic large DNA virus and a single stranded RNA virus) that infect the symbiotic algae of corals. These symbiotic algae, named Symbiodinium, are essential to the health of the animal, and therefore we suspect that these viruses disrupt the collaboration between the corals and their algae, ultimately resulting in a phenomenon called coral bleaching. Further, we have established that viral disease outbreaks are linked to increased nutrients in the water column, increases in seawater temperature, and fragmentation or breakage of corals by hurricanes. Lastly, we have found that viral infection results in reduced coral development and settlement as well as changes in coral larval physiology. Along with these scientific findings, this project provided direct education and training to 2 postdoctoral, 3 graduate, and 6 undergraduate students whose work has been presented at national and international forums and in highly regarded scientific journals. We developed several multimedia productions, blogs, and websites as well as a monthly science café on ocean-related issues called, æEat, Think, and be Merry,Æ which to date has had over 700 attendees in Miami, Fl, USA. Overall this project has created a foundation of information on the causes and dynamics of viral disease in coral biology and ecology and provided hands on training to numerous students at various levels of education. Last Modified: 07/02/2014 Submitted by: Rebecca L Vega