Epigenetics in Aquatic Toxicology

Abstract

Aquatic toxicology is a multidisciplinary, multifaceted field of study that seeks to understand how anthropogenic and natural chemicals interact in marine and freshwater environments and exert adverse effects across the biological hierarchy. Epigenetic mechanisms are recognized as important endpoints to help better understand mechanisms of toxicity as well as potential biomarkers for monitoring ecosystem health and recovery. DNA methylation, histone structure, and the expression of multiple noncoding RNAs can be modified following environmental stress. The use of epigenetic mechanisms as endpoints in aquatic toxicology is still in its infancy and studies are expected to continue to increase as sequencing costs come down. Here we explore the role of epigenetics in aquatic toxicology with an overall focus on the effects of pesticides and other contaminants of emerging concern on aquatic organisms and ecosystems. We begin by reviewing the basics of toxicology and the role of epigenetic mechanisms in xenobiotic metabolism. The role of model organisms and human health toxicology are also briefly discussed. How epigenetic mechanisms are altered following environmental stress, whether these changes are adaptive or maladaptive, correlated to apical endpoints (i.e. survival, reproduction, growth/development), and/or used as molecular biomarkers and endpoints are extensively explored. We also examine topics across climate change, rapid evolution, aquaculture, and risk assessment to provide examples of the variety of subdisciplines aquatic toxicologists may incorporate into studies and how epigenetics advances these areas of study.