Living organisms are influenced by their environment, promoting changes in their phenotypes and function. These acclimatory changes within a lifetime are the consequence of alterations in genome function through epigenetic modifications, or changes in the way the instructions found in DNA are interpreted, without changes in the DNA bases. It is still unclear, however, how environmental signals are transduced into the epigenome, affecting ecological and evolutionary outcomes. This project uses symbiotic, metabolically complex reef-building corals as a model system to test the connections between the environment, energetics, and epigenetics.