海水养殖循环系统不同功能区域微生物群落结构比较

为了探究海水养殖循环系统不同功能区域微生物群落结构特征，深入了解水质理化因子与微生物群落之间的相关性，通过16S rRNA扩增子高通量测序技术对系统不同功能区域水体微生物群落结构进行了分析。结果表明，变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)为整个系统绝对优势菌门，不同功能区域优势属组成差异较大，但是弧菌(Vibrio)丰度都在1%以上。脉红螺养殖池和生物滤池水体α多样性最高，鲍鱼养殖池水体和自然海水多样性最低。NMDS分析结果显示生物滤池和养殖池进水口微生物群落结构相似，其他区域微生物群落结构有明显差异。生物滤池到养殖池NH₄⁺和NO₂^-去除率分别为8.77%和45.12%，NO₃^-质量浓度在整个系统内都处于较高水平(148.50~200.47mg/L)。环境因子与微生物群落结构没有显著相关性，温度T和NO₂^-对微生物群落结构的影响相对较大。研究结果为下一步循环水养殖系统设计的完善和日常管理提供了参考。

Comparison analysis of microbial community structure in different functional areas of recirculating aquaculture system

In order to explore the microbial community structure in different functional areas of recirculating aquaculture system, as well as to understand the relationship between environmental factors and the microbial community, microbial community structure in recirculating aquaculture system was analyzed by using high-throughput sequencing with 16S rRNA in this study. The results showed that Proteobacteria and Bacteroidetes were the most dominant phyla in overall system, the compositions of dominant genera were quite different in different areas of system, while the relative abundances of Vibrio in whole system were both exceeding 1%. α-diversity (Shannon, ACE and chao1) of samples collected from biofilter and Rapana venosa pond were highest, and that in abalone pond and natural seawater were lowest. Non-metric multi-dimensional scaling (NMDS) analysis showed the system areas possessed distinctive distances of microbial communities except samples between biofilter and culture pond inlet. The removal rates of ammonia nitrogen and nitrite nitrogen from biofilter to the inlet of culture pond were 8.77% and 45.12%, respectively. The concentrations of nitrate nitrogen maintained a high level in the whole system (148.50~200.47 mg/L). There was no significant correlations between environmental factors and microbial community structure, temperature and nitrite nitrogen had relatively stronger effects on microbial community structure. This study provides a reference for the design improvement and daily management of recirculating aquaculture system in the next step.