Environmental epigenetics investigates the cause-effect relationships between specific environmental factors and the subsequent epigenetic modifications promoting acclimatory responses in organisms. Given the dynamic and potentially heritable nature of different types of epigenetic marks, environmental epigenetics and its interaction with genetics constitute a promising venue for developing fast and sensible biomonitoring programs. Nevertheless, the lack of epigenetic knowledge in other ecologically and environmentally relevant organisms has hampered our understanding of these mechanisms in a broader range of ecosystems, most notably in aquatic environments. Fortunately, the growing availability of complete reference genome sequences along with the development of high-throughput DNA sequencing and bioinformatic methods are making the epigenetic study of non-model species (and more specifically marine and aquatic organisms) a reality. This session will include studies deepening our understanding of expression regulation in response to environmental cues, as well as studies using environmental epigenetic analyses for critical issues such as conservation and management of natural resources in marine and aquatic environments under global change impacts.