Bacterial Diversity Characteristics In The Soils From Different Eco-environments In Typical Karst Basins

More and more attention is paid to global environmental change and carbon cycle research now. Karstification has proven to have carbon sink effect. In order to clarify the effect of soil microorganism in the process of karst carbon cycle and carbon sink, it is necessary to study the characteristics of soil microbial diversity in karst basin while the current research is lacking. In this paper PCR-DGGE method was used to determine the spatiotemporal characteristics of surface soil bacterial diversity of different eco-environment in typical karst basins. The correlation between surface soil bacterial diversity and surface soil basic physicochemical properties and soil CA activity were preliminary discussed. At the same time the significance of surface soil bacterial diversity on the carbon cycle in the different eco-environment in karst basins was discussed. The main results in this paper are as followed:(1) The diversity index and richness of the surface soil bacterial community in different sampling plots of Changjiang River basin were influenced by the vegetation types and varied according to the season changes which highest in winter, autumn second, summer third and lowest in spring. Correlation analysis showed that the diversity index and richness of the surface soil bacterial community had significantly positive correlation(P<0.05) with the available nitrogen, available phosphorus and available potassium and a certain degree of positive correlation with the SOC and soil CA activity.(2) The diversity index and richness of the surface soil bacterial community in Wujiang River basin upstream were different between different land use types. The arbor lands had the highest average surface soil bacterial community diversity index and richness, the shrub lands second and the agricultural lands were the lowest. Land use types had no obvious effect on the diversity index and richness of the surface soil bacterial community in Yachi River small watershed. Correlation analysis showed that in Wujiang River basin upstream the surface soil bacterial community was significantly positive correlation(P<0.01) with the SOC and in Wujiang River basin upstream the surface soil bacterial community had positive correlation with the soil moisture, available nitrogen, available phosphorus and soil CA activity. In Yachi River small watershed a certain positive correlation was found between the surface soil bacterial community and soil CA activity.In general, the diversity index and richness of the surface soil bacterial community in typical karst basins can be influenced by the eco-environment of the sampling plots and the positive correlation between the diversity index and richness of the surface soil bacterial community with the SOC and soil CA activity implied that bacteria in typical karst basins soil may play a positive role in the soil carbon cycle and the process of carbon sequestration in soil. The intensity of carbon sequestration of the bacteria in typical karst basins soil is worth in-depth study.