Variations in microbial characteristics of overland flow from steep slopes with biocrusts during rainfall in a semiarid region

• Published in: Journal of hydrology (Amsterdam) 2024-05, Vol.635, p.131158, Article 131158
• Main Authors: Chen, Guo, Chang, Chao, He, Xiao-bing, Zhang, Qing-wei, Li, Ming, Wang, Jian, Geng, Ren, Qiao, Jiang-bo, Zhang, Feng-bao, Wang, Hao
• Format: Article
• Language: English
• Subjects: Biocrusts; biological soil crusts; community structure; data collection; functional diversity; microbial communities; Microbial community structure; Migration patterns; mosses and liverworts; overland flow; phylogeny; rain; rainfall duration; rainfall simulation; runoff; Semiarid regions; semiarid zones; Simulated rainfall
• ISSN: 0022-1694
• DOI: 10.1016/j.jhydrol.2024.131158

•Variation of microbial traits in runoff from steep slopes with biocrusts were studied.•Differences in microbial community structure in overland flow from slopes were found.•Microbial community assembly in overland flow from different slopes are different.•Microbial functional potential was gradually increased with the biocrusts succession.•Variation of microbial traits were due to the biocrust types and rainfall duration. Microorganisms within biocrusts are important in semiarid ecosystems. The structure and function of microbial communities in biocrusts have been carefully assessed, while studies on microbial migration patterns during rainfall-runoff processes remain limited. Therefore, we conducted the simulated rainfall experiments on the four runoff plots (i.e., cyanobacteria crust-covered runoff plot (CC), mixed crust-covered runoff plot (MIC), moss crust-covered runoff plot (MOC), and bare runoff plot as the control (CK)) located on the steep slopes covered with biocrusts of different successional stages. The overland flow samples were collected at specific time intervals. The differences in the community structure and assembly processes, network complexity, and functional potential of the microbial community in overland flow and their variations with rainfall duration were systematically analyzed by the high-throughput sequencing dataset combined with qPCR. The results revealed that variations in microbial abundance and diversity of overland flow with rainfall duration were different for both the CK and CC. Microbial abundance in overland flow generally increased, whereas microbial diversity in overland flow were firstly increased and then decreased with rainfall duration. However, microbial abundance and diversity in the overland flow generally decreased with rainfall duration for the MIC and MOC. The microbial richness, phylogenetic diversity and functional diversity of overland flow were significantly affected by the successional stage of the biocrusts within the runoff plots. Specifically, the microbial community assembly processes gradually transitioned from homogeneous selection to stochastic processes with rainfall duration for the CK and CC. In contrast, these processes were not affected by the rainfall duration for the MIC and MOC. Moreover, the complexity of the microbial network in the overland flow generally increased from CC to MOC, and gradually decreased with rainfall duration. Furthermore, the functional potential of the microbial c