腾冲地热区砷的环境生物地球化学研究
发布时间：2024-04-13 10:40
砷是一种有毒的致癌物质,可以通过岩石风化、地热流体、火山喷发等自然过程,也可以通过含砷农药、除草剂的使用、采矿、工业废水的排放、化石燃料的燃烧等人为活动释放到环境中。地热流体中砷的浓度一般在1-10 mg/L,有的甚至高达50 mg/L以上。深部地热流体是一种还原环境,砷主要以三价砷存在。当它上升至地表的过程中遇到浅层富氧的地下水,或者出露地表后的排泄,就会在微生物的作用下被氧气氧化成五价砷。因而汇集地热流体的地下水或者地表水就会含有较高的砷的浓度,从而构成一种潜在的环境威胁。在过去的十年,地热流体来源砷的迁移和转化及其环境威胁越来越引起研究者的关注,并且已经在很多国家调查过,包括美国、加拿大、日本、新西兰、菲律宾、冰岛、法国、西班牙、俄罗斯、土耳其以及像墨西哥、智利等一些拉丁美洲的国家。然而在各种类型热泉的环境中,微生物介导砷的环境地球化学作用还尚不清楚。本研究选取我国典型的高温地热流体云南腾冲地热区为研究区,采用地球化学与微生物分子生态学相结合的方法,分析腾冲地热区砷的地球化学特征和不同类型热泉环境中砷的生物地球化学作用,调查砷功能微生物群落的多样性和丰度,以及研究分离的砷氧化菌作...
【文章页数】：128 页
【学位级别】：博士
【文章目录】：
作者简历
摘要
Abstract
Chapter 1 Introduction
1.1 Geothermal arsenic
1.1.1 Arsenic in the environment
1.1.2 Arsenic distribution and source in geothermal areas
1.1.3 Geochemical characteristics of As in geothermal water
1.1.4 Microbially mediated As transformation in geothermal environments
1.2 Tengchong geothermal area
1.3 Objectives of this study
Chapter 2 Arsenic geochemistry in geothermal systems of Tengchong,China
2.1 Introduction
2.2 Geological setting of the study area
2.3 Materials and methods
2.3.1 Sample collection and preservation
2.3.2 Hydrochemical and statistical analyses
2.4 Results and discussion
2.4.1 Chemical characteristics of geothermal water
2.4.2 Arsenic geochemical behavior of geothermal water
2.4.3 Potential mixing of geothermal water and shallow groundwater and derived As environmental risk
2.5 Summary
Chapter 3 Arsenic biogeochemistry and microbial community at theoutflow of an acid vapor-formed spring
3.1 Introduction
3.2 Materials and methods
3.2.1 Site description
3.2.2 Field measurements and sample collection
3.2.3 Laboratory geochemical analysis
3.2.4 DNA extraction, amplification and sequencing
3.2.5 Sequence data preprocessing and statistical analysis
3.3 Results
3.3.1 Water and sediment geochemistry
3.3.2 Alpha diversity of microbial communities
3.3.3 Microbial community compositions
3.3.4 Microbial community structure statistics
3.4 Discussion
3.4.1 Potential As, S and Fe oxidation processes
3.4.2 Significant environmental factors shaping the microbial community structure
3.5 Summary
Chapter 4 Arsenic biogeochemistry and microbial community at theoutflow of an alkaline sulfide-rich hot spring
4.1 Introduction
4.2 Materials and methods
4.2.1 Site description
4.2.2 Field measurements and sample collection
4.2.3 Laboratory geochemical analysis
4.2.4 As(Ⅲ) oxidization experiments
4.2.5 DNA extraction, amplification and sequencing
4.2.6 Sequence data preprocessing and statistical analysis
4.3 Results
4.3.1 Water and sediment geochemistry
4.3.2 Alpha diversity of microbial communities
4.3.3 Microbial community compositions
4.3.4 Microbial community structure statistics
4.3.5 As(Ⅲ) oxidization and As(Ⅲ) oxidase gene (aioA) diversity
4.4 Discussion
4.4.1 Microbially mediated As species transformation
4.4.2 Significant environmental factors shaping microbial community structure
4.5 Summary
Chapter 5 Diversity and abundance of the As(Ⅲ) oxidase gene aioA ingeothermal areas of Tengchong, Yunnan, China
5.1 Introduction
5.2 Materials and methods
5.2.1 Site description and sample collection
5.2.2 Geochemical measurements
5.2.3 DNA extraction and aioA gene amplification
5.2.4 Clone library construction and phylogenetic analysis
5.2.5 qPCR
5.2.6 Statistical analyses
5.3 Results
5.3.1 Geochemistry
5.3.2 Abundance of aioA and 16S rRNA genes
5.3.3 Diversity of aioA gene
5.4 Discussion
5.4.1 Neutral or alkaline springs contained higher As concentrations than acidic springs
5.4.2 Abundance of aioA and its correlation with environmental factors
5.4.3 aioA origin:bacterial or archaeal?
5.4.4 Different aioA genes in hot springs with different geochemistry
5.5 Summary
Chapter 6 Isolation and identification of As(Ⅲ) oxidizing bacteria inTengchong geothermal area, China
6.1 Introduction
6.2 Materials and Methods
6.2.1 Site description and sample collection
6.2.2 Enrichment and isolation
6.2.3 Phylogenetic analysis
6.2.4 Physiological characteristics and As(Ⅲ) oxidization
6.2.5 As(Ⅲ) oxidase assays
6.3 Results and Discussion
6.3.1 Isolate characterization and identification
6.3.2 As(Ⅲ)oxidization
6.3.3 As(Ⅲ)Oxidase Genes
6.4 Summary
Chapter 7 Conclusions and suggestions
7.1 Conclusions
7.2 Suggestions
Acknowledgements
References
本文编号：3952911
【文章页数】：128 页
【学位级别】：博士
【文章目录】：
作者简历
摘要
Abstract
Chapter 1 Introduction
1.1 Geothermal arsenic
1.1.1 Arsenic in the environment
1.1.2 Arsenic distribution and source in geothermal areas
1.1.3 Geochemical characteristics of As in geothermal water
1.1.4 Microbially mediated As transformation in geothermal environments
1.2 Tengchong geothermal area
1.3 Objectives of this study
Chapter 2 Arsenic geochemistry in geothermal systems of Tengchong,China
2.1 Introduction
2.2 Geological setting of the study area
2.3 Materials and methods
2.3.1 Sample collection and preservation
2.3.2 Hydrochemical and statistical analyses
2.4 Results and discussion
2.4.1 Chemical characteristics of geothermal water
2.4.2 Arsenic geochemical behavior of geothermal water
2.4.3 Potential mixing of geothermal water and shallow groundwater and derived As environmental risk
2.5 Summary
Chapter 3 Arsenic biogeochemistry and microbial community at theoutflow of an acid vapor-formed spring
3.1 Introduction
3.2 Materials and methods
3.2.1 Site description
3.2.2 Field measurements and sample collection
3.2.3 Laboratory geochemical analysis
3.2.4 DNA extraction, amplification and sequencing
3.2.5 Sequence data preprocessing and statistical analysis
3.3 Results
3.3.1 Water and sediment geochemistry
3.3.2 Alpha diversity of microbial communities
3.3.3 Microbial community compositions
3.3.4 Microbial community structure statistics
3.4 Discussion
3.4.1 Potential As, S and Fe oxidation processes
3.4.2 Significant environmental factors shaping the microbial community structure
3.5 Summary
Chapter 4 Arsenic biogeochemistry and microbial community at theoutflow of an alkaline sulfide-rich hot spring
4.1 Introduction
4.2 Materials and methods
4.2.1 Site description
4.2.2 Field measurements and sample collection
4.2.3 Laboratory geochemical analysis
4.2.4 As(Ⅲ) oxidization experiments
4.2.5 DNA extraction, amplification and sequencing
4.2.6 Sequence data preprocessing and statistical analysis
4.3 Results
4.3.1 Water and sediment geochemistry
4.3.2 Alpha diversity of microbial communities
4.3.3 Microbial community compositions
4.3.4 Microbial community structure statistics
4.3.5 As(Ⅲ) oxidization and As(Ⅲ) oxidase gene (aioA) diversity
4.4 Discussion
4.4.1 Microbially mediated As species transformation
4.4.2 Significant environmental factors shaping microbial community structure
4.5 Summary
Chapter 5 Diversity and abundance of the As(Ⅲ) oxidase gene aioA ingeothermal areas of Tengchong, Yunnan, China
5.1 Introduction
5.2 Materials and methods
5.2.1 Site description and sample collection
5.2.2 Geochemical measurements
5.2.3 DNA extraction and aioA gene amplification
5.2.4 Clone library construction and phylogenetic analysis
5.2.5 qPCR
5.2.6 Statistical analyses
5.3 Results
5.3.1 Geochemistry
5.3.2 Abundance of aioA and 16S rRNA genes
5.3.3 Diversity of aioA gene
5.4 Discussion
5.4.1 Neutral or alkaline springs contained higher As concentrations than acidic springs
5.4.2 Abundance of aioA and its correlation with environmental factors
5.4.3 aioA origin:bacterial or archaeal?
5.4.4 Different aioA genes in hot springs with different geochemistry
5.5 Summary
Chapter 6 Isolation and identification of As(Ⅲ) oxidizing bacteria inTengchong geothermal area, China
6.1 Introduction
6.2 Materials and Methods
6.2.1 Site description and sample collection
6.2.2 Enrichment and isolation
6.2.3 Phylogenetic analysis
6.2.4 Physiological characteristics and As(Ⅲ) oxidization
6.2.5 As(Ⅲ) oxidase assays
6.3 Results and Discussion
6.3.1 Isolate characterization and identification
6.3.2 As(Ⅲ)oxidization
6.3.3 As(Ⅲ)Oxidase Genes
6.4 Summary
Chapter 7 Conclusions and suggestions
7.1 Conclusions
7.2 Suggestions
Acknowledgements
References
本文编号：3952911
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