温州市境内城市河流底泥氨氧化菌富集培养物微生物群落结构分析

【背景】城市河流底泥含有丰富的微生物资源,底泥表面更是硝化作用的主要位点之一,其表面微生物在河流生态系统氮的转化过程中发挥着重要作用。【目的】以温州市境内的城市河流水系温瑞塘河茶山段舜岙河和横江河的4条河道作为采样点,比较分析4种不同环境下城市河流表层底泥氨氧化菌富集培养物的微生物群落结构。【方法】通过野外采样及室内培养对底泥中氨氧化功能菌进行富集培养,采用高通量测序技术分析微生物群落的组成、丰度和多样性。【结果】富集培养后主要优势类群为变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)。4个样品共涉及氨氧化细菌3个属,分别为亚硝化单胞菌属(Nitrosomonas)、亚硝化螺菌属(Nitrosospira)、亚硝化球菌属(Nitrosococcus),涉及氨氧化古菌1个属为Nitrososphaera,其中所有样品均以Nitrosomonas为主。不同底泥富集样品氨氧化微生物可操作分类单元(Operational taxonomic unit,OTU)组成存在明显差异,栽种有水生植物的河道底泥样品DA2具有最高的氨氧化细菌OTU数量和相对丰度,而存在生活餐饮污染的河道底泥样品DA4具有最高的氨氧化古菌OTU数量和相对丰度;相较于滞留水体,采自相对流动水体的富集样品DA2、DA4具有更高的氨氧化微生物OTU数量和相对丰度。【结论】阐述了4种不同环境下城市河流底泥氨氧化菌富集培养物微生物群落结构的多样性,确定了富集培养之后的优势类群,为氨氧化微生物培养源的选择提供了参考,也为城市河流底泥中氨氧化菌进一步的筛选分离及其生理生态特征的研究提供了科学依据。

Microbial community structure of ammonia-oxidizing enrichments from urban river sediments in Wenzhou City

[Background] Urban river sediments are rich in microbial resources, and the surface sediment is a major site for nitrification. Microorganisms in surface sediment play an important role in nitrogen transformations of river ecosystems. [Objective] To compare and analyze the microbial communities of ammonia-oxidizing microorganism enrichments from sediments under different environmental conditions, sediment samples were collected at four sampling sites at the Shunao and Hengjiang Rivers, which are tributaries of the Wen-Rui Tang River located in Wenzhou. [Methods] Ammonia-oxidizing microorganism enrichments were obtained through field sampling and laboratory cultivation. The microbial composition, abundance and diversity of ammonia-oxidizing microorganism enrichments were studied by high-throughput sequencing. [Results] Proteobacteria and Bacteroidetes were the two dominant phyla in enrichments. The microbial communities in four samples contained three genera of ammonia-oxidizing bacteria (Nitrosomonas, Nitrosospira and Nitrosococcus) and one genus of ammonia-oxidizing archaea (Nitrososphaera), of which the genus Nitrosomonas was dominant in each sample. There were marked differences in the composition of ammonia-oxidizing microorganism OTUs (operational taxonomic units) among different enrichments. The number and relative abundance of ammonia-oxidizing bacteria OTUs were highest in the sample DA2 from the site that has many aquatic plants, while those of ammonia-oxidizing archaea OTUs were highest in the sample DA4 from the site where untreated municipal wastes are often dumped there. The number and relative abundance of ammonia-oxidizing microorganism OTUs were higher in the enrichment samples DA2 and DA4 from lotic-dominated sites compared to those from lentic-dominated sites. [Conclusion] The results revealed microbial diversity in enrichments from urban river sediments under four different environments, and described the dominant phyla in enrichments. Such data provides a reference for selecting the culture source of ammonia-oxidizing microorganism, and provides fundamental knowledge for isolation and further study of ammonia-oxidizing microorganism in urban river sediments.