Jinhae Bay coast is likely to have continuous community structural changes due to seasonal hypoxia. Conventional methods that rely on morphological identification have limitations in identifying these changes. In the present study, using eDNA metabarcoding technology, the monthly changing zooplankton community composition was investigated and identified around hypoxia period in Jinhae Bay. Study of eight months of eDNA survey confirmed significant changes in community in summer when hypoxia and stratification occurred. This change in composition was largely influenced by phylum Arthropoda that showed a negative correlation with hypoxic water mass, especially in the order Calanoida and Poecilostomatoida, thus confirming negative influence of hypoxia on species diversity. After the disappearance of hypoxia, the species diversity recuperated with recovery of only a few species that had disappeared during hypoxia along with detection of new members of the community. Moreover, environmental factors affecting each ASVs were identified through WGCNA, and nine families assumed to be resistant to hypoxic environment were detected. Our study suggests eDNA metabarcoding as an efficient game changing tool in identification of variations in community composition upon environmental changes in the marine ecosystem.

environmental DNA, hypoxia, ecosystem