铜尾矿废弃地生态恢复过程中参与铁硫氧化和氮转化的功能微生物研究

发布时间：2018-03-01 08:09

本文关键词： 重金属尾矿生态修复铁硫氧化氮转化细菌群落　出处：《安徽大学》2017年博士论文　论文类型：学位论文

【摘要】：矿业尾矿及其相关污染物通过风层分散以及水力侵蚀向外扩散,使它成为造成周围环境土壤、水体和大气污染的重要污染源。植物重建是现今矿业废弃地修复的主要方式,然而尾矿的铁硫氧化过程导致的尾矿酸化以及尾矿自身营养元素匮乏在很长一段时间内限制了尾矿中植物的定植和补充,使得植被修复非常困难。众所周知铁硫氧化菌的存在会加速硫化物矿物的氧化过程,同时微生物氮转化过程也会影响重金属尾矿生态系统的发展。因此生态修复过程能否控制重金属尾矿的铁硫氧化过程和其对氮转化的影响是亟待阐明的。本研究以铜陵市水木冲铜尾矿库为研究对象,主要通过分析其中的微生物组成和功能微生物,探讨重金属尾矿铁硫氧化和氮转化以及植物修复对该过程的影响。主要研究结果如下:1.为分析尾矿酸化过程中活性微生物的组成,本研究使用添加葡萄糖的方式刺激尾矿中大多数微生物的活性。结果发现添加8 mg C/g葡萄糖并没有显著刺激pH 7.5的尾矿中微生物的活性,分别增加了 pH 5.5和pH 3尾矿中微生物的活性。在未添加硝酸铵的情况下,葡萄糖添加后pH 5.5和pH 3尾矿中CO2排放量增加了 3.4倍和2.8倍;在同时添加8 mg C/g葡萄糖和1 mgN/g硝酸铵的情况下,pH 5.5和pH 3尾矿中CO2排放量增加了 9.1倍和39.1倍。在pH 7.5的尾矿中,葡萄糖的添加增加了优势属(相对丰度1%)、次优势属(相对丰度位于0.1%-1%)和非优势属(相对丰度0.1%)的相对丰度,这些微生物隶属于变形菌门、酸杆菌门、放线菌门、拟杆菌门、厚壁菌门和浮霉菌门等。然而随着尾矿酸化的加剧,活性微生物主要属于优势和次优势的类群且仅隶属于变形菌和放线菌。2.本研究分析尾矿上优势植物群落的构建对尾矿的硫化物矿物氧化、细菌群落结构和氮转化功能的影响。结果表明植被构建主要影响表层0-20 cm的尾矿。与裸地尾矿相比,植被构建减缓了表层尾矿pH的降低,具有更低的游离氧化铁含量和硫酸根含量;同时能够降低了关键铁硫氧化细菌的数量。另一方面,优势植被的构建改变了表层尾矿的细菌群落结构,其中alpha-、delta-变形菌门、酸杆菌门、厚壁菌门和硝化螺旋菌门的相对数量出现显著的差异。同时植被构建通过改变nifH基因多样性,提高nifH基因的转录增加表层尾矿的固氮速率和氮含量。此外,研究发现受试区域的白茅是几种植物中能够最有效地减少铁硫氧化微生物的数量以及提高根际固氮基因转录的物种,从而被认为可以作为先锋物种的种植用来抑制硫化物矿物的氧化以及促进固氮微生物的表达。3.本研究通过比较两种用于生态修复的植被重建措施(直接植被重建和自然覆土)下尾矿剖面中的生化特性,研究自然覆土对土壤生物地球化学功能的影响。尾矿覆土区域覆土层约40 cm厚,人工覆土时间长达10年。人工覆土层具有比直接植被种植更高的总氮、总有机碳和含水量和较低的重金属(Fe、Cu和Zn)含量。另外,在覆土区域10-40 cm处的细菌多样性增加,细菌群落结构发生显著改变。人工覆土措施是主要影响尾矿中细菌群落的主要因素,其解释了细菌群落最大的变异(29.96%)。与直接植被重建相比,人工覆土策略显示了较高的酸杆菌门和delta-变形菌门的相对丰度和较低的拟杆菌门、芽单胞菌门、beta-和Gamma-变形菌的相对丰度。PICRUSt分析进一步指出人工覆土导致了能量代谢功能的改变,主要体现在碳氮硫代谢。总之,人工覆土策略可能用来加速自然微生物的建立以及有利于稳定的原生植物物种生物地球化学过程的修复。综上所述,重金属尾矿的生态修复过程并不会因为有机碳的添加导致尾矿酸化的加剧;成功的植被构建能够抑制尾矿中硫化物矿物的氧化并且改善尾矿表层的生物化学性质;尾矿中的先锋群落白茅可以广泛用于尾矿的修复因为其能够抑制硫化物矿物的氧化,延缓铜尾矿酸化进程,同时促进固氮微生物生长;人工覆土能够加快表层尾矿自然细菌群落的形成。
[Abstract]:Mining tailings and related pollutants by wind and water erosion layer scattered outward diffusion, make it become the cause of surrounding soil, an important source of pollution of water and air pollution. The plant is the main way of the reconstruction of mining wasteland restoration. However, iron sulfur oxidation process in tailings tailings tailings acidification and its nutrition in very short for a long time limit of colonization and tailings plant, the vegetation restoration is very difficult. The oxidation process of iron sulfur oxidizing bacteria as everyone knows the existence of sulfide minerals will accelerate, while microbial nitrogen transformation processes will also affect the development of heavy metal mine ecosystem. Therefore the ecological restoration process can iron sulfur oxidation process control of heavy metals in tailings and its effect on nitrogen transformation is the urgent need to clarify. The research on Tongling city water rushed copper tailing as the research object, mainly through Analysis of microbial composition and function of microbial the effect of heavy metal tailings of iron sulfur oxidation and nitrogen transformation and Phytoremediation of the process. The main results are as follows: 1. for the analysis of active microbial tailings acidification process, the activity of most microorganisms using glucose stimulation in the tailings. The results showed that the addition of 8 mg C/g glucose did not significantly stimulate microbial activity in the tailings of pH 7.5, pH 5.5 and pH were increased by 3 in the tailings microbial activity. In the case without the addition of ammonium nitrate, CO2 emissions of glucose after adding pH 5.5 and pH 3 in the tailings increased 3.4 times and 2.8 times; in addition to 8 mg C/g glucose and 1 mgN/g ammonium nitrate under the condition of pH 5.5 and pH CO2 emissions of 3 tailings has been increased by 9.1 times and 39.1 times. In 7.5 pH of tailings, glucose add genera (phase The abundance of 1% times), the dominant genera (relative abundance in non dominant genera (0.1%-1%) and the relative abundance of 0.1%) the relative abundance of these microorganisms belonging to Proteobacteria and acidobacteria, Actinobacteria, Bacteroidetes and Firmicutes and planctomycetes. However, with the aggravation of the tailings acidification the main advantage, microbial activity and belongs to the dominant group and only belong to Proteobacteria and the analysis on the advantages of plant community construction tailings tailings of sulfide minerals oxidation of actinomycetes.2., affecting the function of community structure and nitrogen transformation bacteria. The results show that the main effect of planting tailings was constructed. Compared with the 0-20 cm bare tailings, vegetation construction slowed down the decrease of pH surface tailings, with lower content of free iron oxide and sulfate content; at the same time can reduce the number of key iron sulfur oxidizing bacteria. On the other hand, the construction of the dominant vegetation change table The bacterial community structure, layer of tailings in which alpha-, delta- Proteobacteria, acidobacteria, there was significant difference between the relative number of Firmicutes and nitrospirae. At the same time, vegetation construction by changing the nifH gene diversity, improve the transcription of nifH gene increased the rate of nitrogen fixation surface tailings and nitrogen content. In addition, it is found that the participants of the regional cylindrica is several plants can be the most effective way to reduce the number of iron sulfur oxidizing microorganisms and improve the rhizosphere nitrogen fixation gene transcription species, it is considered as a pioneer species of plant oxidation can be used to inhibit sulfide minerals and promote the expression of.3. of nitrogen fixing organisms this study by comparing the two kinds of measures for vegetation reconstruction ecological restoration (direct vegetation reconstruction and natural soil) and biochemical characteristics of tailing profile in the influence of natural soil on soil biogeochemical functions of the tail. Mine overburden area soil layer about 40 cm thick, artificial soil for 10 years. The artificial soil with planting vegetation than higher total nitrogen, total organic carbon and water content and low heavy metals (Fe, Cu and Zn) content. In addition, the bacterial diversity increased in soil area at 10-40 cm, the bacterial community structure changed significantly. The artificial soil covering measures are the main factors that mainly influence the bacterial community in the tailings, which explains the variation of bacterial community the largest (29.96%). Compared with the direct artificial vegetation restoration, soil covering strategy shows a higher relative abundance of acidobacteria and delta- proteobacteria. And lower bacteriodetes, gemmatimonadetes, beta- and Gamma- analysis further pointed out that the relative abundance of Proteobacteria.PICRUSt artificial soil resulted in energy metabolism changes, mainly reflected in the carbon metabolism of nitrogen and sulfur. In short, artificial soil strategy can be used to accelerate the self However, microbial establishment and repair is conducive to the stability of the native plant species biogeochemical process. In summary, the ecological restoration process of heavy metals in tailings and not because of added organic carbon in tailings acidification intensified; biochemical properties of successful revegetation can inhibit the oxidation of sulfide minerals in tailings tailings and improve the surface of the Pioneer community Imperata; the tailings can be used in the repair of tailings can inhibit the oxidation because of sulfide minerals, delaying the copper tailings acidification process, and promote the growth of nitrogen fixing microorganisms; artificial soil can accelerate the formation of surface layer of tailings natural bacterial communities.

【学位授予单位】：安徽大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X172;X171.4

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