Investigation Of Bacterial Community Structure In Biological Soil Crusts Of Inner Mongolia Deserts

On the fixed and semi-fixed sandlot as well as the flowing sandlot of desert areas, microbes,alga vegetation,lichen and moss can condense soil pellet to form biological soil crusts(BSCs),which owes a dramatically important significance on the soil vegetation recovery in desert areas.This essay,based on the BSCs in Hunsandake desert and Maowusu desert of InnerMogolia as researched target,comparatively analyze the changing features®ular pattern of soil bacterium colony structure,and further identify the status of taxology&systematic growth of BSCs,adopting the method of building up soil bacteria 16S rDNA in clone library.5 libraries was constructed in this article(Sample H1-Sampled in November 2008 from Hunshandake desert,H2-09.4,H3-09.6,H4-09.8;M-Sampled in August 2009 from Muwusu desert).The bacterial community of BSCs were similar,mainly comprises 13 categories,the main component is the Gram-negative proteobacteria(includingα,β,γ,δandε,all the subphylum),and the Gram-positive bacteroidetes,all of libraries include the 4 groups ofα-proteobacteria,Actinobacteria,Cyanobacteria and Bacteroidetes.Among them Sphingomonas subordinate toα-proteobacteria has the highest content(are respectively 14.5%,14%,15.2%,28%,30% in Sample H1,H2,H3,H4andM);Cynaobacteria occupies the following ratio in the library:1.8%,2.3%,4.4%,5.4%and2.2%;while Acinetobacter occupies the following ratio in the library: 18.2%,6.9%,6.5%,6.5%and4.1%,has the secretion of this bacteria can make sands cohered,and further can nurture more microbes.These microbes play a significant role in fixing&recovering sandlots,so active studies have been launched on this bacteria.There also exists proteobacteria(includingβ,δandε,all the subphylum),Thermomicro- bia,Chlamydiae,Firmicutes,Chloroflexi,TM7.The organising feature of bacterial community obviously distinct from mature BSCs,hence,in the early developing period of BSCs,the one which plays a dominant&extending role might be the other heterotroptrophic bacteria and autotrophic bacteria except for Cyanobacteria.Furtherly,this research promotes a better understanding and comprehension on microbe diversity as well as ecological effect of BSCs and also provides foundamental theory basis and technological support for the recovery of ecological system of desert soil.