Responses of Free-Living Community to Seasonal Environmental Variation in a Subtropical Inland Bay.

are widely distributed in aquatic environments and strongly associated with eutrophic environments and human health through the consumption of contaminated seafood. However, the response of the community to seasonal variation in eutrophic environments is poorly understood. In this study, we used a -specific 16S rRNA sequencing approach to reveal the seasonal distribution pattern and diversity of the community in the Maowei Sea, Beibu Gulf of China. The Shannon diversity of the community was highest in the summer, while β-diversity analysis showed that community structures were significantly different between seasons. Distance-based redundancy analysis (dbRDA) and Mantel test analysis suggested that total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), dissolved inorganic nitrogen (DIN), salinity, and temperature were the key environmental factors shaping the community structure, indicating a strong filtering effect of trophic condition on communities. Furthermore, through random forest analysis, , , , , and the other eight species were more sensitive to eutrophic changes. This study revealed seasonal changes in communities and the influence of environmental variation on community composition, contributing to a better understanding of their potential ecological roles in a subtropical inland bay.