[目的]了解罗氏沼虾亲虾越冬时循环养殖系统对水质的调控效果,探明其中微生物群落的作用.[方法]采集循环养殖系统运行88 d后的越冬池池水、池中人工水草(普通纤维膜)以及外置式生物滤器中的纳米纤维膜等3种不同基质上的微生物,利用DNA抽提、PCR扩增和定量以及高通量MiSeq测序技术等对3种不同基质上的微生物进行16S rRNA基因序列V4-V5区的测定和分析,并根据测序得到的双端测序读长(Pair-end reads)进行质量控制和过滤,之后进行操作分类单元(OTU)聚类分析,并基于OTU对微生物群落的多样性指数和群落结构进行分析;每3-4 d对越冬池池水水质进行监测.[结果]养殖池塘的水质保持在良好的状态,其中氨氮和亚硝氮浓度控制在0.17+0.08 mg/L和0.28±0.15 mg/L;不同基质上的微生物组成和多样性都不相同.在3种基质上共检测并鉴定出细菌64种,隶属于9门64属,包括变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、绿弯菌门(Chloroflexi)、厚壁菌门(Firmicutes)、浮霉菌门(Planctomycetes)、硝化螺旋菌门(Nitrospirae)、酸杆菌门(Acidobacteria)和绿菌门(Chlorobi).从属水平上对3种基质上的细菌进行分析,发现养殖池水中含量最高的为丛毛单菌科下的一个未分类类群(Comamonadaceae unclassified),其也是3种基质的共有优势类群;普通纤维膜上为Inhella,纳米纤维膜上则是小纺锤状菌属(Fusibacter).3种基质上细菌群落多样性顺序为:纳米纤维膜＞普通纤维膜＞养殖池水.通过对亲虾越冬养殖全过程的水质监测,发现越冬期间亲虾池水质始终保持在良好状态,并且在循环水系统开启约40 d后水质达到了相对稳定的状态.[结论]通过在育苗池中悬挂人工水草,配合内含纳米纤维膜的外置式生物滤器,可使罗氏沼虾越冬亲虾池保持良好的水质.随着新型材料科学的发展,开发出适用于水产养殖业的滤料很有必要.

In order to study the biodiversity of microbial community structure and explore the water quality purification mechanism of bio-filter in the recirculating aquaculture system for Litopenaeus vannamei,microorganism samples were collected from 5 different positions which were the outer and inner surfaces of the upper part of nano-membrane,the outer and inner surfaces of the lower part of the nano-membrane,and the collecting tray.Microbial diversity,functional microorganisms and purifying capacity among different samples were analyzed according to molecular biological methods and 16S rRNA gene pyro sequencing.The results showed that 10 phyla were identified in 5 different positions,in which Proteobacteria was the dominant group.Nitrospirae was detected in the nano-membrane (4.3％),while with low abundance in the collecting tray (0.33％).Ammonia oxidizing bacteria and nitrite oxidizing bacteria in nano-membrane were the primary microorganisms to remove nitrogen and the proportions were 1.70％ and 6.99％,respectively.There were 41 dominant species identified in total.Among which,Pedobacter was absolutely dominant,Parvularcula was the second dominant species,and both abundance ratios were above 10％.Nitrospira was the third dominant species,whose average abundance on membrane (4.31％) was significantly higher than that in the collecting tray (0.28％).Rich biodiversity of microorganism and stable microorganism ecosystem in the biological filter had a crucial role in buffering water quality.The analysis of effective biomass indicated that nitrification happened mostly in the upper part of the biological filter,and the nitrification effect was weakened in the lower part,while almost disappeared in the collecting tray.Therefore,in order to improve efficiency of nitrification,the hanging membrane density and length should be scientifically designed and rationally distributed.