| Xinjiang is one of the important lake distribution areas in China, where nearly half of natural lakes have been evolved to the salt lake. So,it is also one of the main areas where salt lakes are distributed. Ebinur Lake(81°39′-83°16′E,44°44′-45°08′N) is located at the lowest catchment center in the southwest margin of Xinjiang Junggar Basin. This region features warm temperate continental climate, scarce precipitation, strong evaporation and perennial windiness. Since the 20 th century, under dual influences of regional climatic fluctuation and human activities, the surface of Ebinur Lake has sharply shrunk, the salinity of lake water has been gradually increased, and it has been evolved into the salt lake. Salt lakes with different salt ions contain rich and diversified salt tolerant and halophilic microorganism resources.So, he actinomycetes and archaea diversity in the sediment from Ebinur Lake were investigated by culture-independent method, that is of great significance to enrich researches of microorganism in salt lakes and the influence on microbial diversity at different salt lake development stages in Xinjiang.In the experiment,the sediments of four sampling points located in the place away from 50 m at the lakeside of the northwest part of Ebinur Lake are collected. After mix of samples, physical and chemical factors of sediments are determined,the actinomycetes and archaea diversity in sediment were investigated by culture-independent method.The test result of physical and chemical factors of the sediments shows that pH of the sediments is 8.6, organic matter is 1.45%, potassium ion is 18.8g/kg, calcium ion is 64.4g/kg, sodium ion is 44.2 g/kg, magnesium ion is 22.7 g/kg, chloride ion is 51.7g/kg, sulfate ion is 44.2 g/kg, carbonate ion is 0.07 g/kg, and bicarbonate ion is 0.27 g/kg. Among them, the content of positive ion Na+ and Ca2+ is very high, and the content of negative ion Cl- and SO42- is very high. The salinity of lakebed sediments is 246.34g/kg(dry weight of soil). The result shows that Ebinur Lake has been developed into a salt lake(brine lake). If replenishment still can’t be relieved, Ebinur Lake will be developed towards the stage of self-precipitated salt.In the experiment,45 actinomycetes of OTUs have been obtained. The analysis result of the obtained actinomycete taxon clusters shows that the obtained actinomycetes can be divided into two taxa. The first taxon belongs to Actinobacteria, Actinobacteridae and Actinomycetales. Such taxon includes four suborders including Actinomycineae, Propionibacterineae, Micrococcineae and Corynebacterineae, which accounts for 21.1% of the clone library. The other taxon is unclassified actinobacteria, which accounts for 78.9% of the entire clone library.Besides, in the experiment,34 archaea of OTUs have been obtained from the sediments in Ebinur Lake. They are divided into four taxa. The first taxon belongs to Euryarchaeota, which accounts for 96.6%; the second taxon belongs to Nanoarchaeota, which accounts for 1.1% of the clone library; the first taxon belongs to an unclassified archaebacteria, which accounts for 1.7%; the other unclassified clone accounts for 0.6%. Among them, Euryarchaeota is the main archaea type in the sediments of Ebinur Lake.The experimental analysis result shows that the actinomycetes and archaea 16 S rDNA sequences obtained from Ebinur Lake are not be classified,which indicates that some new taxa of actinomycetes and archaea exist in Ebinur Lake. Meanwhile, through homology comparison it is found that the actinomycetes and archaea 16 S rDNA sequences from Ebinur Lake have high homology with the sequences from other salt lakes, which indicates that microbial resources in similar extreme environment has very high similarity in Xinjiang。... |
PDF Full Text Request