Microorganisms vary in both biomass and diversity composition along glacial depthprofiles. However, it is not well known about the major processes controlling thestructure diversity shift of microorganisms in a glacier, although, aeolian deposition hasbeen widely accepted as one mechanism regulating the distribution of microorganisms insnow. To better understand the distribution of microorganisms in a glacier, variations inbacterial diversity and biomass along a pit profile from the Kuytun 51 Glacier in theTianshan Mountains in China were investigated by using 16S rRNA gene librarysequencing and flow cytometric analysis with cell sorting markers. Four clone librarieswere established from each of the different sampling depths from the snow pit. A total of311 insert clones were preliminarily screened by HaeIII-based amplified rRNA restrictionanalysis (ARDRA), and 83 representatives of the unique ARDRA patterns weresequenced. Sequence analysis showed that the bacteria in the snow pit were affiliatedwith 23 known subphyla within the members of the Proteobacteria, Bacteroidetes,Actinobacteria, Firmicutes, and Cyanobacteria phyla. To examine diversity shifts insnow, the diversity structures from the snow pit were also compared with thosepreviously recovered from the different habitats along the Kuytun 51 Glacier surface andfrom the deep Malan Glacier. The results showed structure shift patterns in bacterialdiversity among the surface, deep snow, and deep ice. Sequence analysis displayed adramatic diversity shift from a mixture of Cyanobacteria and other eubacteria across theglacial surface to other eubacteria without Cyanobacteria in the deep snow. However, thebiogeochemical analyses showed great variability in the measured abiotic and bioticcomponents along the pit profile, which reinforced the idea of aeolian deposition being adominant mechanism controlling the size and diversity of microorganisms in snow.Overall, the findings indicated a significant bacterial diversity shift between the surfaceand deep snow, confirming our hypothesis of a postdeposition influence on the microbialdiversity structures in the glacier.
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