Environmental RNA Biomarkers: Rethinking What Aquatic Monitoring Can Measure

Environmental DNA has transformed how aquatic species are detected, but environmental RNA (eRNA) may provide something more: information about what organisms are doing. Realizing that potential requires understanding how RNA moves from an organism into the environment, what controls the signal that remains, and how that information can be preserved and interpreted. Across a series of controlled aquatic experiments, this work traces eRNA from its biological origins through environmental transport and loss, using a mass-balance framework to separate release, degradation, and sedimentation. These dynamics are then connected to practical approaches for preserving eRNA and, ultimately, to targeted biomarkers that detect physiological responses directly from water. Together, the research explores how environmental samples can move aquatic monitoring beyond identifying which species are present toward measuring how organisms are responding to their environment.