泰山云雾分粒径液滴化学组分及其细菌群落的研究

发布时间：2018-02-02 13:55

本文关键词： 云雾水样品三级采样器化学组成细菌群落　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：云雾事件是由气相、液相组成的混合系统。研究云雾的生成过程和探讨云雾的形成机理,可以揭示大气组分在云雾中的迁移转化规律,对研究污染物的生成和转化具有重要意义。本次泰山观测实验于2015年06月至2015年08月在泰山山顶进行,共计监测记录到20个云雾发生过程,收集到了 17组三级云雾水。在本次泰山云雾水观测实验过程中,首次配置三级云雾水采样器进行样品采集。分粒径采集的云雾水样品随后进行了分析测定,包括云雾水的pH值、水溶性离子、痕量金属元素以及细菌群落分析,其中的部分项目的测定是在采集完毕以后现场立即进行的,如云雾水的pH和电导,样品采集完毕后立即取小部分样品并使用pH计、电导计进行测定;部分项目的测定是将样品保存好移送至实验室内进行的,如表征云雾水氧化还原性的小分子H2O2、HCHO和S(IV)等在采样结束后一小时内通过化学方法进行测定,以避免因样品长期存储而引起的待测组分损失问题;而水溶性离子、痕量金属元素和细菌群落分析则分别将样品冷冻保存,待观测实验完成后带回实验室统一分析测定。测定结果分析显示:三级云雾水样品的pH值表现出随着云雾液滴粒径的减小而降低的趋势;硫酸根(SO42-)、硝酸根(NO3-)以及铵根(NH4+)是云雾水样品中最主要的二次无机离子,它们的离子浓度随着云雾液滴粒径的不同而展现出不同的分布情况。NH4+在偏小的液滴(第2级和第3级)中浓度较高一些;在多数样品中,SO42-的最高浓度出现在第2级中(12组)并且最低浓度出现在第3级中(13组)。NO3-在偏大的液滴(第1级和第2级)中浓度较高一些。除此之外,钙离子(Ca2+)浓度在小粒径、中粒径、大粒径样品中的浓度依次升高。进一步的分析认为:三级云雾水样品中,小粒径的样品pH值最低是其中含有较多的酸性离子(SC42-和NO3-)和较少的碱性离子(NH4+和Ca2+)所共同引起的。本次研究首次对分粒径云雾水中的细菌群落进行了探究,研究表明:云雾水中占主导的细菌属包括乳杆菌属(Lactococcus)(平均丰度34.9%)和芽孢杆菌属(acillus)(平均丰度34.0%)。LEfSe分析进一步展示了细菌群落随云雾液滴粒径变化的差异:拟杆菌属(Bacteroides)是样品中拟杆菌科(Bacteroidaceae)的唯一菌属,同时也构成了第1级(粒径最大液滴)云雾水样品的特征分类群;地杆菌属(Pedobacter)是第2级云雾水样品的特征分类群;放线菌门是第3级云雾水样品中的特征分类群。这些差异很可能是由于云雾水中细菌的粒径所决定的。细菌群落进行环境因素的冗余分析发现:H2O2,NO2-浓度以及痕量金属元素均对细菌群落有着复杂的影响,
[Abstract]:Cloud event is a mixed system composed of gas phase and liquid phase. Studying the formation process of cloud and fog and discussing the formation mechanism of cloud and fog can reveal the law of the migration and transformation of atmospheric components in cloud and mist. This observation experiment was carried out from June 2015 to August 2015 at the top of Mount Tai. A total of 20 cloud and fog processes were recorded. 17 groups of third-level cloud and fog water were collected. In this experiment, the sample was collected with a three-stage water sampler for the first time. The sample of cloud and fog water collected by particle size was then analyzed and determined. These include pH values, water-soluble ions, trace metal elements and bacterial community analysis, some of which are determined immediately after collection, such as the pH and conductance of cloud and fog water. After the sample is collected, a small part of the sample is taken and the pH meter is used to measure the sample. Some of the tests were carried out by transferring the samples to the laboratory, such as H _ 2O _ 2, a small molecule that characterizes the redox property of cloud and mist water. HCHO and Schiv were determined by chemical method within one hour after sampling to avoid the loss of the components to be tested due to the long-term storage of the samples. Water soluble ions, trace metal elements and bacterial community analysis were used to freeze the samples. The results show that the pH value of the third-order cloud and mist water sample decreases with the decrease of droplet size. So _ 42-H _ 2SO _ 4, no _ 3) and NH _ 4) are the most important secondary inorganic ions in cloud and mist water samples. Their ion concentration is different with the droplet size of cloud and mist. The concentration of NH4 is higher in the smaller droplets (grade 2 and stage 3). In most samples. The maximum concentration of SO42- appears in group 2 / 12) and the lowest concentration appears in group 3 / 13 (grade 1 and level 2) in larger droplets (stages 1 and 2). Medium concentration is higher. Other than that. The concentration of Ca ~ (2 +) in the small, medium and large size samples increased in turn. Further analysis showed that the concentration of Ca ~ (2 +) in the third-order cloud and mist water samples increased in turn. The pH value of the sample with small particle size is the lowest, which contains more acidic ions SC42- and NO3) and less alkaline ions (NH4 and Ca2). This study was the first time to explore the bacterial community in cloud-mist water with particle size. The results show that the dominant bacteria in the water of cloud mist include Lactococcus (mean abundance 34.9m) and Bacillus acillusus (P < 0.05). The analysis of the mean abundance of Bacteroides further showed the difference of bacterial community with droplet size: Bacteroides is a family of Bacteroides (Bacteroides) in the sample. The sole genus of Bacteroidaceae. At the same time, it also forms the characteristic classification group of the first grade (largest droplet size) cloud and mist water sample. The genus Pedobacter is the characteristic taxa of the second grade of cloud and mist water samples. Actinomycetes is the characteristic taxa in the third grade cloud and mist water samples. These differences are probably determined by the size of bacteria in the cloud and mist water. The redundancy analysis of the environmental factors found that: h _ 2O _ 2 was used in the bacterial community. The concentrations of NO2- and trace metal elements have complex effects on the bacterial community.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X513;P426

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