EDNA Sampler: A fully integrated environmental DNA sampling system

Abstract

Abstract Species monitoring using environmental DNA (eDNA) is a powerful new technique for natural resource scientists and the number of research groups employing eDNA detection is growing rapidly. However, current eDNA sampling technologies consist mainly of do‐it‐yourself solutions, and the lack of purpose‐built sampling equipment is limiting the efficiency and standardization of eDNA studies. Here, we describe the first fully integrated sampling system (Smith‐Root eDNA Sampler) designed by a team of molecular ecologists and engineers for high‐throughput eDNA sample collection. It consists of a backpack portable pump that integrates sensor feedback, a pole extension with remote pump controller, custom‐made filter housings in single‐use packets for each sampling site and onboard sample storage. The system is optimized for sampling speed and replicability, while minimizing risk of contamination. We present an example pilot study designed to identify optimal eDNA Sampler system parameter values (i.e. pump pressure, flow rate, filter pore size, sample volume) in a new sampling environment. We identified a peak in filtration efficiency at a flow rate threshold of 1.0 L/m, and found that 5 μm filters captured significantly more target eDNA than 1 μm filters. Results also suggest that high filtration pressures may reduce eDNA retention, which implies that pressure should be standardized to avoid biasing detection data. Similar to the technological evolution of backpack electrofishers, eDNA sampling technology is in the process of transitioning from a nascent phase to professionally engineered research tools. Such innovations will be essential as eDNA monitoring becomes one of the industry standard methods used for species detection and management.