Applied Soil Ecology ( IF 4.8 ) Pub Date : 2021-02-10 , DOI: 10.1016/j.apsoil.2021.103916 Jing Guo , Yuxiu Zhang , Hai Huang , Fan Yang
Subsidence caused by underground coal mining results in soil degradation. However, little is known about bacterial community structure and its response to a 1-year-old coal mining subsidence area in arid and semiarid areas northwest China. Soil samples from 5 unexplored areas (MC, RC, YC, LC and ZC) and a 1-year-old subsidence area above a coal working face were collected and soil biogeochemical properties and bacterial community structure were determined. Results showed electrical conductivity (EC), soil water content (SWC), soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), dissolved organic carbon (DOC), available nitrogen (AN), available phosphorus (AP) and available potassium (AK) decreased with depth. The microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and the activity of β-1,4-glucosidase (BG), β-1,4-N-acetylglucosaminidase (NAG), alkaline phosphatase (PP) and catalase (CAT) were also reduced. The nutrients, BG, PP and MBC in subsidence of marginal zone of a coal working face were significantly lower than those in control, suggesting subsidence led to a loss in nutrients and a reduction in microbial biomass. High-throughput sequencing revealed that the Sphingomonas, Gemmatimonas, Pseudomonas and Gp6, involved in C and N nutrient cycles, were dominant in this region. The relative abundances of Sphingomonas, Pseudomonas and Arthrobacter were decreased in subsidence due to the nutrient leakage and microbial biomass reduction. The predicted abundances of genes for metabolisms of xenobiotics via cytochrome P450 pathways and nitrogen were low in marginal zone, while peroxidase was high, indicating low capacities of degrading for xenobiotics and polycyclic aromatic hydrocarbons (PAHs) occurred marginal zone, while resistance to hydrogen peroxide was strengthened. Redundancy analysis (RDA) revealed EC, SWC and soil depth governed bacterial community structure. Overall, subsidence caused losses in soil water, nutrients and microbial biomass, alteration of bacterial community structure, and ultimately reduced soil nutrient conversion. Therefore, the cracks in the subsidence area should be filled manually in time, especially in marginal zone.