Microbial vertical diversity in core sediments and its response to environmental factors near the hydrothermal field of the southern Okinawa Trough

In recent years, microbe and its adaptation mechanism in submarine hydrothermal environment have become the focus of marine science research. At present, relevant researches focus on the horizontal distribution diversity of surface sediments and microorganisms, and only few researches on the vertical distribution diversity of microorganisms in columnar sediments. Based on the columnar sediment samples from the S2 station in the southern hydrothermal area of the Okinawa Trough in the western Pacific Ocean, we revealed the vertical community distribution characteristics of culturable microorganisms and the overall microorganisms in the samples through isolation, culture, and high-throughput sequencing of 16S rRNA gene from the samples at different levels. At the same time, the microbial community structure and its response to environmental factors were discussed by using statistical methods such as the evaluation of major elements, trace elements, carbon and nitrogen contents, and redundancy analysis. Results show that the organic matter content of the core sediment at this site is relatively poor, and Cu-Zn-Pb is rich in two layers; the microbial community of each layer is composed of mainly Proteobacteria, while the surface sediments exhibit higher microbial diversity. Meanwhile, it indicated a closer relationship between the organic carbon content of core sediments and the composition of their microbial communities. This study obtained bacterial strain resources and provided a basis for further research into microbial participation in the geochemical cycle of elements in submarine hydrothermal environment.