Microbial Diversity Analysis Of The Salt Lakes In Badain Jaran Desert

In Badain Jaran desert, most of salt lake is alkaline, salinity is up to 470 g/L, while p H between 9 to 11. As a result of the groundwater recharge, there are many freshwater lake there, thus, salinity gradient change appears, microbial resources are very abundant. The microbial community structure under different salinity and alkalinity were investigated deeply by the methods of molecular ecology with Clone Library Sequencing(CLS) and High Throughout Sequencing(HTS) as well as Mothur and R software. This research discussed the relationship between biodiversity and environmental factors. Which revealed microbial diversity of desert salt lakes and provided theoretical and technical support for extreme microbial classification and identification. The results of this study were:(1) The diversity of bacteria was higher than archaea. Bacteria mainly belong to Proteobacteria, Bacteroidetes, Firmicutes, Verrucomicrobia. While archaea belong to Euryarchaeota only.(2) Microbial diversity in soil samples is generally greater than in water samples. When the coverage is over 99.5%, 16 categories were identified in water samples while 37 categories in soil samples, Shannon diversity index and Simpson’s diversity index of soil samples were higher than water samples.(3) The cluster of samples were affected majorly by salinity. Samples with high salinity clustered together, so were low salinity. The relative ratio of bacteria to archaea was influenced by salinity, higher salinity brought about more archaea.(4) There was no obvious relationship between diversity and salinity. High shannon diversity could be detected in freshwater lakes, salt lakes, moderate salt lakes and extreme salt lakes. Besides, the fluctuation of alkalinity was 8.52 ~ 10.27 and the diversity did not show linear variation.(5) PSB and SOB were key factors of sulfur biological cycle in soda lakes and abundance in samples are very high. Bacteria contained in soil samples were basically SOB which belong to Sulfuricurvum, Desulfonatronospira and Dethiobacter. The amount of SOB in water samples were less than soil samples, which belong to:1) non-halophilic Thiothrix, distributed only in fresh water lakes; 2) moderately halophilic Spiribacter, existed in high and moderate salt lakes.(6) In fresh water lakes,most of the bacteria are SOBs and cyanobacteria; In moderate salinity salt lakes,Halorubrum and Halomonas, which belong to moderate halophilic bacteria, are the dominent; In high salinity lakes, extremely halophilic archaea with rhodopsinth distribution mostly, such as Halohasta.