The primary aim of this project is to characterize and monitor physiological and genetic baseline parameters in marine sponges and their associated microbial symbionts using modern molecular methods, before and after exposure to petroleum products. This project will develop sponges and their microbes as potential “sentinel” species to assess the impact of past and potential oil contamination on reef habitats. Sponges and their associated microbes are excellent environmental sentinels. Using next generation molecular tools such as transcriptomics and metagenomics, we will simultaneously trace the direct impact of crude oil (and byproducts) and dispersants on both sponge physiology (a general marker of reef health) and sponge microbial community dynamics (a general marker of regional seawater quality). Evaluating shifts in the composition and function of these organisms and their resident microbes will allow us to determine the overall effects of hydrocarbon loading in the water column that have resulted from the Deepwater Horizon oil spill. Controlled oil exposure pilot experiments will also be performed in closed aquaculture systems.