Distribution of arsenite-oxidizing bacteria and its correlation with environmental factors in geothermal areas of Tengchong, Yunnan, China

摘要

Arsenic (As) is an ubiquitous constituent in geothermal water. Arsenite (AsIII) is oxidized via microbial processes as the waters equilibrate with oxygen in the geothermal effluent. The distribution of arsenite oxdizing bacteria and its correlation with environment factors were studied in Tengchong geothermal areas of Yunnan, China. A total of 230 aioA clone sequences were obtained and these sequences were affiliated with four phyla: Betaproteobacteria, Alphaproteobacteria, Deinococcus-Thermus and Aquificae. Temperature was negatively correlated with aioA diversity and was the only environment factor that had correlation with diversity index. Betaproteobacteria was mainly distributed in low temperature (T = 28 to 43°C) and circumneutral or light alkaline (pH = 7 to 9) springs; Alphaproteobacteria was mainly predominant in low pH (pH = 3.3 to 3.6) springs; Deinococcus-Thermus and Aquificae mainly inhabited in high temperature (T=55 to 78°C) springs with a wide range of pH. Usually, Deinococcus-Thermus was dominant when springs had a pH within 4.0 to 8.0. Aquificae was dominated in springs with pH > 8.0 or pH < 4.0.