杭州西湖沉积物中产甲烷菌群落结构和多样性研究

发布时间：2019-05-14 13:07

【摘要】：湖泊湿地是甲烷气体的重大排放源。产甲烷菌在地球生物化学碳素循环过程中起着关键作用,它是产生温室气体的主要因素之一。探究湖泊沉积物中产甲烷菌可为甲烷气体的排放研究提供生物学支撑。本文以杭州西湖为研究对象,采用限制性片段长度多态性分析及分子克隆等技术,研究了西湖春夏两季不同区域沉积物中产甲烷菌群落结构和多样性,并分析水生植物、沉积物营养水平等对菌落的影响。主要结果如下:1、通过产甲烷菌16SrDNA克隆文库的酶切图谱分析,冬季西湖共得到38种酶切类型。测序结果表明,西湖共存在着4种菌目:甲烷微菌目、甲烷八叠球菌目、甲烷杆菌目和甲烷球菌目,前两种菌目均隶属于甲烷微菌纲,该菌纲在西湖各子湖中作为优势种存在,部分比例高达68%。隶属于各甲烷菌目的甲烷菌科检测出7种,分别为M.sarcinaceae、M.caldococacceae、M.regulaceae、M.microbiaceae、M.bacteriaceae、M.thermaceae和M.saetaceae。2、夏季西湖共得到21种酶切类型,检测出3种菌目:甲烷微菌目、甲烷八叠球菌目和甲烷杆菌目,其中,同属于甲烷微菌纲的甲烷微菌目、甲烷八叠球菌目的比例差异性较大;前者作为优势菌存在,含量明显高于后者。隶属于各甲烷菌目的甲烷菌科有5种:M.microbiaceae、M.bacteriaceae、M.saetaceae、M.regulaceae和M.saricinaceae,甲烷微菌科仍作为优势菌科存在于各子湖中,后三者所占比例较少,皆低于15%。3、冬季西湖湖西区和外湖区沉积物中,产甲烷菌16SrDNA克隆文库的酶切类型分别是23、24种。反映湖西区沉积物产甲烷菌群落结构多样性的Shannon指数介于1.978-2.323,而外湖区该指数最大值仅为2.002,大部分均低于1.978,Simpson多样性指数规律与其类似,说明湖西区各子湖产甲烷菌结构的多样性高于外湖区各子湖。另外,冬季湖西区各子湖的甲烷菌科种类高于外湖区各子湖,M.sarcinaceae和M.caldococaceae仅在湖西区发现。4、冬季湖西区各子湖水生植物恢复区的产甲烷菌菌落均匀度高于匮乏区,但产甲烷菌种类规律不明显,茅家埠的恢复区和匮乏区的产甲烷菌纲数量等同;乌龟潭匮乏区的菌纲种类高于恢复区1种;而浴湖湾的结论与之相反。可能因为各子湖恢复区的水生植物覆盖率和生长周期不同,外加沉积物本底营养物浓度的综合作用所致。5、在冬夏季节,甲烷微菌科均作为优势菌科存在,比例高达50%。但冬季西湖产甲烷菌结构和种类多样性高于夏季,M.thermaceae和M.caldococcaceae仅在冬季检测到。可能由于大部分水生植物在夏季处于生长旺盛期,根系泌氧作用对于沉积物中局部氧化还原状态的贡献较大,一定程度上抑制厌氧产甲烷菌的生长。
[Abstract]:Lake wetland is an important source of methane gas emission. Methanogenic bacteria play a key role in the process of biogeochemical carbon cycle, and it is one of the main factors to produce greenhouse gases. To explore the methanogenic bacteria in lake sediments can provide biological support for the study of methane gas emissions. In this paper, the community structure and diversity of methanogenic bacteria in sediments of different regions of West Lake in spring and summer of Hangzhou were studied by restriction fragment length polymorphism analysis and molecular cloning, and aquatic plants were analyzed. Effects of sediment nutrition level on colony. The main results are as follows: 1. A total of 38 restriction endonuclease types were obtained in West Lake in winter by restriction endonuclease analysis of methanogenic bacteria 16SrDNA clone library. The results of sequencing showed that there were four species of bacteria in the West Lake: methane microflora, methane octacoccus, methanomycetes and methanomycetes. The first two bacteria belonged to methane microflora, which existed as dominant species in each lake of the West Lake. Some of them are as high as 68%. Seven species of methanomycetes belonging to various methanogens were detected, which were M. sarcinaceae, M. caldococacceae, M. microbiaceae, M. thermaceae and M. saetaceae.2. A total of 21 enzyme digestion types were obtained in the West Lake in summer. Three kinds of bacteria were detected: methane microbacteria, methanosporium and methanomycetes, among which, the proportion of methane microbacteria belonging to methane microflora and methanosporium was quite different. The former exists as the dominant bacteria, and the content of the former is significantly higher than that of the latter. There are five species of methanomycetes belonging to each order: M. microbiaceae, M. bacteriaceae, M. saetaceae, M. regulaceae and M. saricinaceae. methane microbacteria still exist as dominant bacteria in each lake, and the proportion of the latter three is less than 15%. In winter, the restriction endonuclease types of methanogenic bacteria 16SrDNA clone libraries in the sediments of West Lake and Outer Lake were 23 and 24 species, respectively. The Shannon index, which reflects the diversity of methanogenic bacteria community in the western part of the lake, is between 1.978 and 2.323, while the maximum value of the index is only 2.002, most of which are lower than 1.978. the law of Shannon diversity index is similar to that in the outer lake area. The results showed that the diversity of methanogenic bacteria structure in the western lake was higher than that in the outer lake. In addition, the methanogens of each lake in winter were higher than those in the lake, and M.sarcinaceae and M.caldococaceae were only found in the west of the lake. 4. The uniformity of methanogenic bacteria in the recovery area of aquatic plants in the western part of the lake was higher than that in the scarce area. However, the species of methanogenic bacteria was not obvious, and the number of methanogenic bacteria in the convalescent and scarce areas of Maojiabu was the same. The species of bacteria in Wuqiutan fatigue area were higher than those in restoration area, but the conclusion in Bath Lake Bay was opposite. It may be due to the different coverage and growth cycle of aquatic plants in each sub-lake restoration area, and the comprehensive effect of sediment background nutrient concentration. 5. In winter and summer, methane microflora exists as the dominant family, the proportion is as high as 50%. However, the structure and species diversity of methanogenic bacteria in West Lake in winter were higher than those in summer, and M.thermaceae and M.caldococcaceae were only detected in winter. It may be that most aquatic plants are in the peak growth period in summer, and the root oxygen secretion contributes greatly to the local redox state in sediments, and to a certain extent, it can inhibit the growth of anaerobically methanogenic bacteria.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X172

【参考文献】