Genetic analysis of marine water samples based on eDNA methods assumes that samples are taken in a very clean and conscientious way avoiding every potential risk of contamination with other eDNA molecules that do not belong to the respective water sample. A rosette sampler with a CTD sensing system that is equipped with 5-L-Niskin bottles is used for water sampling. Samples are collected at the desired stations during surveys on research vessels. To prove the absence of DNA contamination every survey should include a sampling control from each Niskin bottle used. Careful cleaning of used gears, materials and surrounding areas is a main requirement to yield reliable results in genetic downstream analysis. To guarantee the traceability of the samples, correct labelling and documentation of water sampling are needed.
Eschbach et al. (2025) studied this question.