不同类型冰川雪中可培养细菌多样性变化及其与环境因子关系研究

Culturable Bacteria in Snow Pits of Different Type Glaciers:Diversity and Relationship with Environment

通过荧光显微计数和恢复培养,分析了东天山和卓奥友峰冰川区雪的细菌数量及可培养细菌多样性.结果表明:不同地点不同深度雪中微生物数量都与可溶性离子Ca2+、Mg2+和NO3-等的浓度显著相关,两种不同类型冰川雪坑中可培养细菌多样性存在明显差异.从卓奥友样品中培养得到高G+C(67%)、低G+C(22%)、α-Proteobacteria(4%)、β-Proteobacteria(4%)、γ-Proteobacteria(1%)和Cytophaga-Flavobacterium-Bacteroides(CFB)(2%)6种不同类群细菌,但从东天山雪样中仅分离得到β-Proteobacteria(48.5%)、α-Proteobacteria(25.5%)、低G+C(25%)和高G+C(1%)4种不同类群细菌.冰雪微生物的数量及种类与环境密切相关.

Snow samples at different depths were collected from two different types of glaciers, one from Mt. Cho Oyu, the Himalayas and another from East Tianshan Mountains, China. Total bacteria abundance were determined by 4＇, 6-diamino- 2-phenylindole （DAPI）. Culture-dependent method was used to examine the bacterial diversity. The microbial abundance has a close relationship with major ion concentrations. The ions, such as Ca^2＋, Mg^2＋ and Cl^- etc., are good indicators of climate and environment. The volume of microbe changes with depths for both two sampling sites. The snow pits in the East Tianshan Mountains have more microbial abundance than that in the Mr. Cho Oyu. The 16S rDNA gene of culturable bacteria from Mt. Cho Oyu snow pit belongs to the following groups： proteobacteria （α-, β-, γ-）, Cytophaga-Flavobacteriurn-Bacteroides （ CFB） , high GC and low GC. Among them, the high GC is the dominant group. However, the 16S rDNA gene of culturable bacteria from the East Tianshan Mountains belongs to proteobacteria（a-, β-）, high GC and low GC. Among them, β-Proteobacteria is the dominant group. It is revealed that the snow bacteria community is controlled by many factors. The study indicates that the microbial abundance and the diversity of culturable bacteria in snow are dependent on the environment and the geographical position very significantly.