PS 64-73
Effects of precipitation variation on distribution pattern of soil bacterial diversity in broad-leaved Korean pine mixed forest
Precipitation-induced soil moisture changes will directly influence water utilization of plants and soil microbes and will indirectly influence the functions and processes of terrestrial ecosystems. In a forest ecosystem, soil microbes are easily influenced by environmental factors resulting in variation. In this study, we used high-throughput 454 sequencing to study the bacterial community in surface soils (at soil depths of 0 to 5 cm and 5 to 10 cm) and in the rhizosphere soil of the virgin broad-leaved Korean pine mixed forest on Changbai Mountain. We analyzed such parameters as bacterial diversity, community structure, and sample similarity in sample plots with different precipitation levels. Our goal was to investigate the effects of variation in precipitation on the soil microbe community and to reveal spatial heterogeneity of soil microbes that might be driven by this variation. This work may provide a theoretical basis and scientific reference for further research into the response patterns of soil bacterial communities to variation in precipitation in broad-leaved Korean pine mixed forests.
Results/Conclusions
The results showed that the diversity and the richness of soil bacteria decreased with soil depth. The diversity and evenness of soil bacteria responded differently for precipitation variation in two layers of topsoil, and the diversity and evenness of rhizosphere decreased as precipitation increased. The bacterial diversity index is related with soil physical and chemical properties and microbial biomass, especially significantly correlated with soil organic carbon. The significant correlation between bacterial diversity index and soil organic carbon indicates that soil organic matter plays a decisive role on soil bacteria community in acidic soil.
The dominant microorganism population in different precipitation plots was same: Proteobacteria, Acidobacteria, Planctomycetes, Actinobacteria and Chloroflexi. From the sample similarity, we found that precipitation variations influenced the soil bacterial community composition, and the response magnitude of topsoil differed from rhizosphere.
Precipitation variation changed abundance of dominant microorganism population, but did not change the type of advantage bacterium group. The response mechanism of dominant microorganism population for precipitation variations is different with each other.