摘要：Large-scale biomonitoring of Arctic coastal marine communities is essential to track temporal changes in ecosystems. Despite the potential of environmental DNA (eDNA) as an innovative coastal biomonitoring tool, important questions remain pertaining to its temporal and spatial variation and how this may affect the evaluation of ecosystem changes over time in hydrodynamic ecosystems. In this study, we used eDNA metabarcoding of coastal water samples in two Canadian Arctic ports to evaluate the potential of eDNA to detect temporal transition in marine coastal communities. We sequenced eDNA from approximately 20 surface water samples collected each month ( N ≈ 150 samples) covering the transition period between summer and late fall using four different universal primer pairs (two pairs of COI mitochondrial genes and two pairs of 18S rRNA genes). Our results from both primer pairs highlighted a significant transition from the summer to the fall marine community. We also observed a putative link between eDNA peaks of read abundance and timing for different life stages (e.g., spawning and larvae) of several species with the most abundant sequence reads. As such, our results show that temporal variation must be considered in ensuring comprehensive coastal biomonitoring with eDNA. Although much remains to be investigated about the ecology of eDNA, our results contribute to fundamental knowledge on the origin of eDNA and highlight the importance of considering temporal variation in developing guidance for coastal biomonitoring with this approach.
