| Karst terrains extend over 20% of the earth’s surface.Caves, one of the most important forms of karst topography, are very important tourism resources and rich speleothems formed by deposition and many dissolution at features.Compared with the external environment, the environment inside a cave is relatively closed and stable. The environment inside cave is dark, damp, and temperature stability. Nutrition conditions in such a relatively poor environment, there are still many kinds of microbial life. Caves are also generally isolated from the influence of solar UV radiation and physical weathering due to wind, rain,or freezing.The knowledge of nutrient cycling in aphotic systems is limited, especially in the context of how nutrient cycling and microbial diversity might be linked. Caves are important and relatively accessible habitats to study subsurface microbial diversity.The ecological system of Groundwater system takes an important part of the Critical Zone. For the growth of microorganisms to provide the conditions such as Nutrition, water pH, osmotic pressure and temperature. Provide a good living place for microorganisms. Microbes in caves closely related with cave environments, and play a very important role in the substance circulation and the energy flowing. Community structure and diversity of microorganisms is important to clarify the relationship between microbial community structure and their environment, and to explore the development and use of microbial resources, reveal aspects of the relationship between structure and function in the community and so on.Few reports of microbial groups associated with the groundwater flow system are available in China. Selected xueyu cave and shuiming cave which located at chongqing as the research station. First of all, using the traditional method of cultivating plate count to research the spatial distribution and time distribution of three types of microorganisms (bacteria, fungi, actinomycetes) in the subterranean streams. Due to the inherent defects of traditional training methods,we analyzed by 16S rRNA gene analytical methods to acquire the data of microorganism communities’ distribution of microorganism in groundwater samples from the xueyu cave and shuiming cave. Conclusions were drawn as followed:(1) In a seasonal scale, Three types of microorganisms(Bacteria, actinomyces and fungi) are relatively small in the dry season, more during the rainy season, This trend were positively correlated with changes of precipitation and temperature.The change between bacteria and actinomycetes, fungi are not synchronized, When the number of fungi, actinomycetes in the trough in January, bacteria have a modest increase instead. This may be related to the ability of bacteria to survive, while the main source of fungi and actinomycetes is soil and air, Less precipitation at this time, Soil fungi and actinomycetes into the cave through the underground river is relatively small, and it is a off season for cave tourism at the same time.Therefore,a very small cave tourists, microorganisms by visitors into the cave is relatively small.(2)In the spatial scales, under the same geological and environmental conditions, human activity has significant impact on the number and community of caves microbes.Microbiological data of different sampling points in Xueyu Cave showed that:The number of microorganisms underground river at different sampling points were significantly different. Diminishing from the entrance to the cave inside. At the same time the composition of the microbial community structure of different sampling points are different. There are significant differences in the microbial population cave tour and unexplored caves in microbial populations. Microorganisms are rich in the tourist caves, while poor in the unexplored caves. This shows that the undeveloped cave by human interference is relatively small and thus better maintain the microbial population characteristics of the original cave.(3) The microbial diversity of xueyu cave is higher than the shuiming cave.(4)The advantage of bacteria in xueyu cave is:Alphaproteobacteria,beta proteobacteria, Gammaproteobacteria, Epsilonproteobacteria, Actinobacteria, Sphingobacteria, Bacteroidetes, Firmicutes, Cyanobacteria. The advantage of bacteria in shuiming cave is beta proteobacteria, Gammaproteobacteria, Flavobacterium, Nitrospira.The advantage of Fungi is same between xueyu cave and shuiming cave Agaricomycetes, Microbotryomycetes, Sporidiobolales, Clitopilus, Trichosporon,Chytridiomycota,Blastocladiomycota,Eurotiomycetes,Microascales,Diaporthales,Asp ergillus,Mycosphaerella,Saccharomycetales,Pucciniomycetes,Malasseziales.The advantage of Archaea is same between xueyu cave and shuiming cave:Crenarchaeota, Euryarchaeota, Thaumarchaeota.(5) In summary it can be inferred that human activities Significantly affect the Microorganism of xueyu cave on the dry season. |
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