title: Depth-resolved abundance and diversity of arsenite-oxidizing bacteria in the groundwater of Beimen, a blackfoot disease endemic area of southwestern Taiwan.
abstract: The role of arsenite oxidizers in natural attenuation of arsenic pollution necessitates studies on their abundance and diversity in arsenic-contaminated aquifers. In this study, most probable number-polymerase chain reaction (MPN-PCR) and denaturing gradient gel electrophoresis (DGGE) was applied to monitor depth-wise abundance and diversity of aerobic arsenite oxidizers in arsenic-enriched groundwater of Beimen, southwestern Taiwan. The results revealed that the abundance of arsenite oxidizers ranged from 0.04 to 0.22, and the lowest ratio was observed in the most arsenic-enriched and comparatively more reduced groundwater (depth 200 m) of Beimen 1. The highest ratio was observed in the less arsenic-enriched and less reduced groundwater (depth 60 m) of Beimen 2B. DGGE profiles showed a shift in diversity of arsenite oxidizers, consisting of members of the Betaproteobacteria (61%), Alphaproteobacteria (28%) and Gammaproteobacteria (11%), depending on mainly arsenic concentration and redox level in groundwater. Groundwater with the lowest arsenic and highest dissolved oxygen at Beimen 2B harbored 78% of the arsenite oxidizers communities, while groundwater with the highest arsenic and lowest dissolved oxygen at Beimen 1 and Beimen-Jinhu harbored 17 and 22% of arsenite oxidizers communities, respectively. Pseudomonas sp. was found only in groundwater containing high arsenic at Beimen 1 and Beimen-Jinhu, while arsenite oxidizers belonging to Alpha- and Betaproteobacteria were dominated in groundwater containing low arsenic.
authors.affiliation: Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: Suvendu
authors.initials: S
authors.lastname: Das
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kar
authors.forename: Jiin-Shuh
authors.initials: JS
authors.lastname: Jean
authors.forename: Jagat
authors.initials: J
authors.lastname: Rathod
authors.forename: Sukalyan
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Hsiao-Sheng
authors.initials: HS
authors.lastname: Liu
authors.forename: Jochen
authors.initials: J
authors.lastname: Bundschuh
mesh_terms: D020561:Alphaproteobacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D018053:Arsenites / Q000378:metabolism*; D020562:Betaproteobacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D044822:Biodiversity; D058645:Denaturing Gradient Gel Electrophoresis; D019353:Endemic Diseases; D060587:Groundwater / Q000032:analysis / Q000737:chemistry / Q000382:microbiology*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism; D013624:Taiwan; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D018053:Arsenites; D014874:Water Pollutants, Chemical; C015001:arsenite
keywords: Arsenite oxidizing bacteria; Groundwater arsenic; MPN-PCR; PCR-DGGE