Temperature May Play a More Important Role in Environmental DNA Decay than Ultraviolet Radiation

Abstract

Environmental DNA (eDNA) preservation is crucial for biological monitoring using eDNA technology. The decay of eDNA over time in natural water bodies and the effects of temperature and ultraviolet (UV) radiation on the decay rate are largely unknown. In this study, the linear and exponential decay models were used to explore the relationship between residual eDNA content and decay time, respectively. It was found that the residual eDNA content treated with a higher temperature decreased by an average of 89.65% at the end of experiment, while those in the 4 °C treatment group remained stable. The higher decision coefficient (R2) of the exponential decay models indicated that they could better reflect the decay of eDNA over time than linear. The difference in the decay rates of the exponential modes was slight between the 20 °C (25.47%) and 20 °C + UV treatment groups (31.64%), but both were much higher than that of the 4 °C group (2.94%). The results suggest that water temperature significantly affected the decay rate of eDNA, while UV radiation had little effect.