| 作者简历 | 第7-9页 |
| 摘要 | 第9-12页 |
| Abstract | 第12-15页 |
| Chapter 1 Introduction | 第20-31页 |
| 1.1 Geothermal arsenic | 第20-28页 |
| 1.1.1 Arsenic in the environment | 第20-23页 |
| 1.1.2 Arsenic distribution and source in geothermal areas | 第23-24页 |
| 1.1.3 Geochemical characteristics of As in geothermal water | 第24-25页 |
| 1.1.4 Microbially mediated As transformation in geothermal environments | 第25-28页 |
| 1.2 Tengchong geothermal area | 第28-29页 |
| 1.3 Objectives of this study | 第29-31页 |
| Chapter 2 Arsenic geochemistry in geothermal systems of Tengchong,China | 第31-46页 |
| 2.1 Introduction | 第31-32页 |
| 2.2 Geological setting of the study area | 第32-33页 |
| 2.3 Materials and methods | 第33-35页 |
| 2.3.1 Sample collection and preservation | 第33-34页 |
| 2.3.2 Hydrochemical and statistical analyses | 第34-35页 |
| 2.4 Results and discussion | 第35-45页 |
| 2.4.1 Chemical characteristics of geothermal water | 第35-41页 |
| 2.4.2 Arsenic geochemical behavior of geothermal water | 第41-43页 |
| 2.4.3 Potential mixing of geothermal water and shallow groundwater and derived As environmental risk | 第43-45页 |
| 2.5 Summary | 第45-46页 |
| Chapter 3 Arsenic biogeochemistry and microbial community at theoutflow of an acid vapor-formed spring | 第46-65页 |
| 3.1 Introduction | 第46-48页 |
| 3.2 Materials and methods | 第48-52页 |
| 3.2.1 Site description | 第48页 |
| 3.2.2 Field measurements and sample collection | 第48-49页 |
| 3.2.3 Laboratory geochemical analysis | 第49-50页 |
| 3.2.4 DNA extraction, amplification and sequencing | 第50-51页 |
| 3.2.5 Sequence data preprocessing and statistical analysis | 第51-52页 |
| 3.3 Results | 第52-61页 |
| 3.3.1 Water and sediment geochemistry | 第52-55页 |
| 3.3.2 Alpha diversity of microbial communities | 第55-56页 |
| 3.3.3 Microbial community compositions | 第56-58页 |
| 3.3.4 Microbial community structure statistics | 第58-61页 |
| 3.4 Discussion | 第61-64页 |
| 3.4.1 Potential As, S and Fe oxidation processes | 第61-62页 |
| 3.4.2 Significant environmental factors shaping the microbial community structure | 第62-64页 |
| 3.5 Summary | 第64-65页 |
| Chapter 4 Arsenic biogeochemistry and microbial community at theoutflow of an alkaline sulfide-rich hot spring | 第65-83页 |
| 4.1 Introduction | 第65-66页 |
| 4.2 Materials and methods | 第66-69页 |
| 4.2.1 Site description | 第66-67页 |
| 4.2.2 Field measurements and sample collection | 第67-68页 |
| 4.2.3 Laboratory geochemical analysis | 第68页 |
| 4.2.4 As(Ⅲ) oxidization experiments | 第68页 |
| 4.2.5 DNA extraction, amplification and sequencing | 第68-69页 |
| 4.2.6 Sequence data preprocessing and statistical analysis | 第69页 |
| 4.3 Results | 第69-79页 |
| 4.3.1 Water and sediment geochemistry | 第69-72页 |
| 4.3.2 Alpha diversity of microbial communities | 第72-73页 |
| 4.3.3 Microbial community compositions | 第73-75页 |
| 4.3.4 Microbial community structure statistics | 第75-78页 |
| 4.3.5 As(Ⅲ) oxidization and As(Ⅲ) oxidase gene (aioA) diversity | 第78-79页 |
| 4.4 Discussion | 第79-82页 |
| 4.4.1 Microbially mediated As species transformation | 第79-81页 |
| 4.4.2 Significant environmental factors shaping microbial community structure | 第81-82页 |
| 4.5 Summary | 第82-83页 |
| Chapter 5 Diversity and abundance of the As(Ⅲ) oxidase gene aioA ingeothermal areas of Tengchong, Yunnan, China | 第83-99页 |
| 5.1 Introduction | 第83-84页 |
| 5.2 Materials and methods | 第84-87页 |
| 5.2.1 Site description and sample collection | 第84页 |
| 5.2.2 Geochemical measurements | 第84页 |
| 5.2.3 DNA extraction and aioA gene amplification | 第84-85页 |
| 5.2.4 Clone library construction and phylogenetic analysis | 第85-86页 |
| 5.2.5 qPCR | 第86页 |
| 5.2.6 Statistical analyses | 第86-87页 |
| 5.3 Results | 第87-94页 |
| 5.3.1 Geochemistry | 第87-90页 |
| 5.3.2 Abundance of aioA and 16S rRNA genes | 第90-92页 |
| 5.3.3 Diversity of aioA gene | 第92-94页 |
| 5.4 Discussion | 第94-97页 |
| 5.4.1 Neutral or alkaline springs contained higher As concentrations than acidic springs | 第94页 |
| 5.4.2 Abundance of aioA and its correlation with environmental factors | 第94-96页 |
| 5.4.3 aioA origin:bacterial or archaeal? | 第96-97页 |
| 5.4.4 Different aioA genes in hot springs with different geochemistry | 第97页 |
| 5.5 Summary | 第97-99页 |
| Chapter 6 Isolation and identification of As(Ⅲ) oxidizing bacteria inTengchong geothermal area, China | 第99-109页 |
| 6.1 Introduction | 第99-100页 |
| 6.2 Materials and Methods | 第100-102页 |
| 6.2.1 Site description and sample collection | 第100页 |
| 6.2.2 Enrichment and isolation | 第100页 |
| 6.2.3 Phylogenetic analysis | 第100-101页 |
| 6.2.4 Physiological characteristics and As(Ⅲ) oxidization | 第101-102页 |
| 6.2.5 As(Ⅲ) oxidase assays | 第102页 |
| 6.3 Results and Discussion | 第102-108页 |
| 6.3.1 Isolate characterization and identification | 第102-105页 |
| 6.3.2 As(Ⅲ)oxidization | 第105-107页 |
| 6.3.3 As(Ⅲ)Oxidase Genes | 第107-108页 |
| 6.4 Summary | 第108-109页 |
| Chapter 7 Conclusions and suggestions | 第109-112页 |
| 7.1 Conclusions | 第109-110页 |
| 7.2 Suggestions | 第110-112页 |
| Acknowledgements | 第112-113页 |
| References | 第113-128页 |
