Acoustic localization and positioning techniques for environmental DNA sampling applications

A new approach is being developed to integrate passive acoustic sensing with environmental DNA (eDNA) sampling for enhanced marine species monitoring. Acoustic signal processing provides real-time information on the presence and location of vocalizing animals, while eDNA offers a complementary record of recent biological activity—even after animals have moved on. Together, these methods enable adaptive sampling strategies that improve detection rates and reduce reliance on blind sampling, especially for elusive or transient species. Most underwater acoustic systems use single hydrophones and lack directional or synchronized environmental data, limiting their effectiveness. The PLUTOS system (Passive Localized Underwater Transiting Observing System) addresses this gap with multiple 3-D hydrophone arrays capable of classifying and localizing marine species using beamforming and time-difference-of-arrival techniques. Designed as a low-cost, moored or drifting platform, PLUTOS supports multi-modal sensing, including acoustic, physical, and eDNA data streams. A recent field test in Ashumet Pond (Falmouth, MA) using synthetic seal calls from multiple locations demonstrated successful source separation and localization, validating the system’s core capabilities. Challenges and potential solutions for determining array position and orientation during drifting deployments will also be discussed, as precise localization is essential for correlating acoustic and eDNA signals. [Work supported by NSF.]