浙闽沿海生态牧场技术示范区浮游细菌群落和功能的时空变化

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

摘要:

【目的】本文通过不同季节的4个航次调查研究了2个浙闽沿海生态牧场技术示范区的浮游细菌群落的变化，揭示了示范区菌群结构的时空变化，探究其对于海洋生态系统的潜在影响。【方法】使用16S rRNA基因扩增子测序技术，对2个示范区4个季节航次共128个样点中浮游细菌的16S rRNA基因V4区序列进行测序，并通过分析其组成和多样性，借助FAPROTAX功能预测，分析不同季节和示范区浮游细菌的差异。【结果】128个样品量化后共获得2 510 976条优质序列，2个示范区的主要优势浮游细菌类群均为α变形菌纲、γ变形菌纲、β变形菌纲、放线菌纲、黄杆菌纲等，2个示范区浮游细菌的α多样性指数随季节演替而产生波动，且大多数环境因子都与其具有显著相关性；浙闽沿海浮游细菌的群落构建过程随时空变化而产生差异，扩散限制是2个示范区浮游细菌群落构建过程中占比最大的生态过程(除台山岛示范区秋季)，2个示范区多数季节的浮游细菌群落相似性基于Bray-Curtis的地理距离衰减印证了这一点；基于FAPROTAX功能预测得到的2个示范区浮游细菌的功能以化能异养和氮硫循环为主，从一定程度上与当地的环境因子变化相关联。【结论】浙闽沿海生态牧场技术示范区的浮游细菌群落结构受地理距离、理化因子和季节影响存在显著时空变化，且以化能异养为主的浮游细菌的潜在生态功能在不同季节具有显著变化，掌握浮游细菌群落变化规律有助于在微生物层面为我国海洋牧场建设提供理论支持。

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.