Marine invertebrates in the Caribbean basin have experienced several severe epizootic events in recent decades that have resulted in population collapse of the impacted species. The well-documented die-off episode of the long-spined sea urchin Diadema antillarum (Philippi, 1845) in the early 1980s, stands out among these events. The collapse in this keystone species resulted in a significant top-down trophic cascade in which macroalgae cover increased significantly, altering the reef community. Nearly 40 years later, Diadema populations in many localities have not recovered to pre-die-off density levels. Early in 2022, a new mortality event of D. antillarum has been reported in the U.S. Virgin Islands and eastern Puerto Rico. Preliminary observations in several localities in Culebra Island (midway between USVI and PR) indicate that close to 90% of the urchins are dead. However, mortality has not been observed yet on the main island of Puerto Rico. 

This study aims to: 1) provide insights into the causative agent(s) of this disease by applying high-resolution metagenomics; 2) determine the metabolic footprint of microbes from urchins with contrasting health conditions, by applying metabolomics strategies; 3) study the effects of the disease at the population and community levels by establishing monitoring sites along the northeastern coast of Puerto Rico during the early stage of the disease; 4) Determine if abiotic variables such as temperature, pH, dissolved oxygen and conductivity/salinity, significantly influence disease prevalence.