Spatial and temporal changes of bacterioplankton community and function in Zhejiang and Fujian coastal ecological pasture technology demonstration areas

Abstract:

[Objective] This study investigated the temporal and spatial changes of bacterioplankton community in Zhejiang and Fujian coastal ecological pasture technology demonstration areas through four voyages in different seasons, aiming to explore their potential impact on the marine ecosystem. [Methods] The 16S rRNA gene V4 region of bacterioplankton was sequenced for 128 samples from four seasonal voyages in two demonstration areas. The composition, diversity and functions of bacterioplankton were compared among different seasons and between different demonstration areas.[Results] A total of 2 510 976 high-quality bacterioplankton sequences were obtained from 128 samples after quantization. The main dominant bacterioplankton groups in the two demonstration areas were Alphaproteobacteria, Gammaproteobacteria, Betaproteobacteria, Actinobacteria, Flavobacteria, etc. The α-diversity index of the bacterioplankton in the two demonstration areas fluctuated with seasonal succession and had significant correlations with most of the environmental factors. The bacterioplankton community assembly in Zhejiang and Fujian coastal areas varied over time, and diffusion restriction was the most important ecological process in the two demonstration areas (except the Taishan island demonstration area in autumn). This finding was confirmed by the distance decay of Bray-Curtis similarity in the two demonstration areas. The prediction with functional annotation of prokaryotic taxa (FAPROTAX) demonstrated that the bacterioplankton in the two demonstration areas were mainly involved in chemoheterotrophy and nitrogen/sulfur cycle, which were associated with the changes of local environmental factors to a certain extent. [Conclusion]The structure of the bacteiroplankton community in Zhejiang and Fujian coastal ecological pasture technology demonstration areas was affected by geographical distance, physicochemical factors, and seasons. The potential ecological functions of bacterioplankton dominated by chemoheterotrophs varied among different seasons.Revealing the changes of potential ecological functions and community assembly of bacterioplankton provides theoretical support for the future development of marine pasture at the microbial level.

Key words:ecological pasture;bacterioplankton;16S rRNA gene;community assembly;function prediction