Bacterial communities in habitats of Dongchuan, China: Their role in slate weathering in triggering and flowing areas of debris flow

Abstract

Debris flow is one of the most severe disasters in China’s mountainous areas. Landslide soil materials are deposited on steep hill terrains or in channels and, once triggered by heavy rainfall, they can evolve into lethal debris flows. Some studies have suggested a prominent role of rock weathering in the formation of large landslides. In the present study, the a-diversity, composition, and weathering potential of bacterial communities inhabiting surfaces of slate rocks from the triggering area (altered less or more) and slate rocks from the flowing area of debris flows were studied. We found that a-diversity indices were positively correlated with the organic matter content, and Firmicutes accounted for about 66% of the total bacterial community. The variation in bacterial community composition was majorly driven by available Ca. The highest relative abundances of genetic families associated with organic acid production, flagellar assembly and carbonic anhydrase were found in surfaces of less-altered slate rocks from the triggering area by using PICRUSt. All the bacterial strains isolated from rock surface have the ability to accelerate the weathering of slate, among which Pantoea and Pseudomonas genera showing the highest ability to enhance the dissolutions of Fe, Si, Al, and Ca from slate. These results indicated an important role of the rock surface-inhabiting bacterial communities in the weathering of slate in both triggering and flowing areas of debris flow. This study also provides new insights into the biological characterizations of rocks in debris flow areas of Dongchuan, China.