Abstract: To investigate the water quality variations and microbial community structure in the aquaculture zone of a freshwater pond with an embedded container recirculation aquaculture system, this study measured water quality indicators in the zone containing a three - stage biofilter (sedimentation tank, oxidation tank, purification tank, and filter dam) and biofill (filter cotton and brush). High - throughput sequencing was also employed to analyze the microbial community structure in the water column of each biofilter and on the biofill. Results indicate that the water purification system in the aquaculture zone operates stably and effectively, with the treated water quality meeting aquaculture requirements. The removal rates of ammonia nitrogen (NH4+-N), nitrite nitrogen (NO2--N), and total nitrogen (TN) were 52.97%, 63.23%, and 53.51%, respectively. The bacterial community in the aquaculture zone consisted mainly of 33 phyla, including Proteobacteria, Actinobacteria, and Bacteroidota. In the biofilter, the bacterial community structure of the biofilm differed from that of the water column, with a significantly higher relative abundance of Actinobacteria on the biofilm (P < 0.05). The water column samples had higher bacterial community diversity and richness than the biofilm samples. Correlation analysis revealed that NH4+-N, NO2--N, and TN significantly influenced the microbial community structure in the water column group (P < 0.05), while TP, AP, and DO had a more significant impact on the bacterial community structure in the biofilm group. In conclusion, the three - stage biofilter can effectively increase the microbial flora that promotes nitrogen and phosphorus metabolism, contributing to stable water quality. These findings provide theoretical support for the construction and water quality regulation of freshwater pond embedded container recirculation aquaculture systems.

Key words: assembly tank recirculating aquaculture system, biofilter, biofilm, microbial community, 16Sr RNA

摘要： 为研究淡水池塘嵌入式集装槽循环水养殖系统养水区的水质变化以及微生物群落结构特征，测定了养水区3级生物滤池（沉淀池、氧化池、净化池、过滤坝）及生物填料（过滤棉、毛刷）所在区域的水质指标；利用高通量测序技术测定了各生物滤池水体中及生物填料上的微生物群落结构。结果显示：养水区净水系统稳定有效运行，经过各生物滤池处理后的水质最终符合养殖用水的要求。其中氨氮（NH4+-N）、亚硝酸盐氮（NO2--N）、总氮（TN）的去除率分别达到52.97%、63.23%、53.51%。养水区细菌群落主要由变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、拟杆菌门（Bacteroidota）等33个门组成，生物滤池中水体和滤料上生物膜细菌群落结构有所差异，生物膜的放线菌门（Actinobacteria）相对丰度显著高于水体（P＜0.05）。水体样本组的细菌群落多样性高于生物膜样本组，水样中的细菌种类更多，细菌群落的丰富度较高。相关性分析显示，NH4+-N、NO2--N和TN环境因子显著影响水体组微生物群落结构（P＜0.05），总磷（TP）、有效磷（AP）、溶氧（DO）是对生物膜组细菌群落结构影响较大的环境因子。研究表明，3级生物滤池可有效增加水体中促进氮、磷代谢的微生物菌群，有利于保持水质的稳定，研究结果可为淡水池塘嵌入式集装槽循环水养殖系统构建及水质调控提供理论支撑。

关键词: 集装槽循环水养殖系统, 生物滤池, 生物膜, 微生物群落, 16Sr RNA