青藏高原冻土区石油污染对土壤微生物多样性的影响研究

发布时间：2018-07-24 15:10

【摘要】：近年来,我国青藏高原冻土区石油开采、运输、加工等过程中事故频发,对冻土土壤环境造成严重污染。本文对青藏高原冻土区土壤石油污染微生物多样性进行研究,对北麓河地区土壤温度连续监测,富集筛分石油土著低温菌,通过高通量测序技术,分析石油污染下冻土区微生物的种群结构变化以及混合石油菌的生物种群结构,结合实验室低温模拟冻土石油污染修复试验,研究土著低温石油菌在不同实验条件下对土壤石油污染物修复效果,旨在为冻土区石油类污染生物修复工程提供技术支持。本文主要成果为以下几个方面:(1)青藏高原北麓河地区夏季7月中旬至9月上旬土壤温度最高,为微生物活性最高时间段,是青藏高原石油污染微生物修复的关键季节。北麓河土壤显弱酸,有机质含量较高,石油污染微生物修复所需的营养元素在北麓河区域土壤中含量较高,总氮、总磷等基本可以满足低浓度石油污染生物修复的需求,对于高浓度石油污染修复,则需采用添加营养剂的方法满足修复过程中对营养盐的需求。(2)石油污染影响土壤微生物种群结构,高通量测序显示北麓河地区未污染土壤(表层、下层)、柴油污染土、机油污染土中优势菌群存在较大差异,反映了油类污染对土壤微生物结构产生了较大的影响,改变了原有群落结构,致使部分微生物消亡,同时对适应以油类为C源的降解菌群所占比重提高,现场油类污染有利于高效油类降解菌的实验室筛选驯化。(3)恒温震荡培养箱对土著低温石油菌进行富集筛选,利用微生物平板法结合电子显微镜进行检验,显示柴油、机油菌液生长形态以杆状为主。低温营养摇瓶条试验显示:柴油低温降解菌17天对柴油的降解率达60%以上;机油低温降解菌30天对机油的降解率达54.7%。(4)高通量测序分析显示:土著低温柴油降解菌、机油降解菌在种群结构上存在一定的相似性,主要为变形菌门。土著低温柴油降解菌测序显示为71个菌种,优势菌群为Alkanindiges(54.4%)和Pedobacter(18.2%);土著低温机油降解菌测序显示为91个菌种,优势菌群为PYR10d3_norank(23.0%)、Sulfuritalea(19.4)、Parvibaculum(10.94%)和Sphingobium(10.89%)。(5)柴油降解土壤试验显示噬冷柴油降解菌液对柴油污染具有较好的降解效果,提高菌液配比、添加营养盐和表面活性剂可提高其降解效率;在不同柴油污染强度下,菌液对土壤柴油降解的效率具有显著差异,低污染强度下降解效率远高于高污染强度。
[Abstract]:In recent years, oil mining, transportation, processing and other accidents occurred frequently in the frozen soil area of Qinghai-Tibet Plateau, which caused serious pollution to the frozen soil environment. The microbial diversity of soil oil pollution in frozen soil of Qinghai-Xizang Plateau was studied in this paper. The soil temperature was continuously monitored and screened by high-throughput sequencing technique. This paper analyzes the changes of microbial population structure in frozen soil under petroleum pollution and the biological population structure of mixed petroleum bacteria, and combines with laboratory experiments to simulate oil pollution in frozen soil at low temperature. In order to provide technical support for bioremediation of petroleum pollution in frozen soil, the remediation effect of indigenous low temperature petroleum bacteria on soil oil pollutants under different experimental conditions was studied. The main achievements of this paper are as follows: (1) the soil temperature is the highest from mid-July to early September in the northern part of Qinghai-Xizang Plateau in summer, which is the most active period of microorganism, which is the key season for microbial remediation of oil pollution in Qinghai-Tibet Plateau. The soil of the Beilu River shows weak acid, the content of organic matter is high, the nutrient elements needed for the microbial remediation of petroleum pollution are higher in the soil of the Beilu River region, the total nitrogen and total phosphorus can basically meet the demand of bioremediation with low concentration of petroleum pollution. For the remediation of high concentration oil pollution, it is necessary to use the method of adding nutrients to meet the demand for nutrients. (2) Oil pollution affects the structure of soil microbial population, and high-throughput sequencing shows that the soil is not contaminated in the Beilu River region. In the lower layer, the dominant microflora in diesel-contaminated soil and oil-contaminated soil is different, which reflects that oil pollution has a great influence on soil microbial structure, which changes the original community structure and results in the extinction of some microbes. At the same time, the proportion of biodegradable bacteria adapted to C source was increased, and field oil pollution was beneficial to the laboratory screening and domestication of high-efficiency oil-degrading bacteria. (3) enrichment and screening of indigenous low-temperature petroleum bacteria in constant temperature shock incubator. The microbiological plate method combined with electron microscope showed that the growth of diesel oil and oil was mainly rod-like. The low temperature nutrition flask test showed that the degradation rate of diesel oil was over 60% in 17 days and 54.7% in 30 days. (4) High throughput sequencing analysis showed that the degradation rate of diesel oil was 60% in 17 days, and 54.7% in 30 days. (4) the results of high throughput sequencing showed that the degradation rate of diesel oil was 60% in 17 days, and 54.7% in 30 days. There was some similarity in the population structure of oil degrading bacteria, mainly Proteus. Alkanindiges (54.4%) and Pedobacter (18.2%) were dominant strains in 71 strains of native low-temperature diesel oil degrading bacteria and 91 strains of native low-temperature oil degrading bacteria were sequenced. The results showed that PYR10d3_norank (23.0%) Sulfuritalea (19.4) Parvibaculum (10.94%) and Sphingobium (10.89%). (5) had better degradation effect on diesel oil pollution. Under different pollution intensity of diesel oil, the degradation efficiency of bacteria solution on soil diesel oil was significantly different, and the degradation efficiency of low pollution intensity was much higher than that of high pollution intensity.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;X172

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