Spatiotemporal Dynamics of Vibrio Communities and Abundance in Dongshan Bay, South of China

Abstract

The <i>Vibrio</i> genus inhabit estuarine and marine ecosystem throughout the world and can cause severe infections in humans and animals. Previous studies have demonstrated the dynamics of <i>Vibrio</i> at both community and population levels and assessed the close relationship between environmental factors and <i>Vibrio</i> diversity and abundance, such as temperature, salinity, and dissolved oxygen. It is also generally believed that aquaculture is the fastest-growing food sector, which is also applying great environmental impacts on microbial communities in aquatic ecosystems. However, our understanding of the spatiotemporal quantification of <i>Vibrio</i> throughout the four seasons in the aquaculture zone and response to environmental factors remains poor. To explore the spatiotemporal distribution and abundance of the <i>Vibrio</i> community with their related environmental factors and detect the relationships among them, we collected 10 seawater sites spanning four seasons across the whole year in Dongshan Bay for investigating the <i>Vibrio</i> community dynamics. Marked differences in diversity and abundance of the <i>Vibrio</i> community were observed between seasons, which were mainly driven by temperature, dissolved oxygen, nitrate, and nitrite. qPCR analysis showed that <i>Vibrio</i> abundance was most abundant in the summer (5.37 × 10⁶ copies/L), compared with the autumn (4.58 × 10⁶ copies/L), spring (1.18 × 10⁶ copies/L), and winter (1.55 × 10⁴ copies/L). A total of 22 <i>Vibrio</i> operational taxonomic units (OTUs) and 28 species were identified by universal bacteria 16S rRNA gene and cultivation methods, with <i>Vibrio fortis</i> the dominant in these aquaculture areas. To summarize, our present study is one of the few studies to research the occurrence of <i>Vibrio</i> in marine aquaculture of South China, and the results indicate that <i>Vibrio</i> are widely distributed in aquaculture environment and that a further risk assessment is needed to be conducted.