Deciphering Metazoan Community Dynamics Using eDNA in a Human-Impacted Gulf Ecosystem: Spatiotemporal Patterns and Environmental Drivers

Simple Summary Coastal seas are increasingly affected by human activities such as urban expansion and industrial development, which can disrupt marine life and ecosystem stability. Semi-enclosed gulfs are particularly vulnerable because water exchange is limited, allowing pollutants and nutrients to accumulate more easily. In this study, we explored how small marine animals, which form the base of ocean food webs, change across seasons and under different levels of human influence in the Beibu Gulf. Our results show that seasonal environmental changes play a stronger role than location in shaping these communities. At the same time, areas with intense human activity tend to lose their unique biological characteristics, while less disturbed island regions still maintain distinct communities. These findings highlight the combined influence of natural variability and human pressure on marine ecosystems. Understanding these patterns is important for improving conservation strategies and supporting sustainable management in coastal regions facing rapid development.