Differences in geological conditions have reshaped the structure and diversity of microbial communities in oily soils

High-throughput sequencing was used to study the microbial community structure diversity changes in oil-contaminated soils under different spatial distances and environmental conditions. 239 Phyla, 508 Classes, 810 Orders, 1417 Families, 2048 Genera, 511 Species of microbial communities were obtained from 16 samples in three regions. The physicochemical properties of the soil, microorganisms' community structure has been changed by Petroleum hydrocarbon (PHA). Alpha diversity results showed that the soil contained high bacterial diversity, especially in Qingyang's loess soil. The bacterial abundance was in the order of loess soil > black soil > sandy soil. Beta diversity revealed that spatial distance limitation and random variation of repeated samples may be the main factors leading to soil heterogeneity and microbial community structure differences. The dominant bacteria phyla with broad petroleum hydrocarbon degradation ability such as Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were identified. Pseudomonas, Bacillus, Nocardioides, Oceanobacillus, Sphingomonas, Alkanindiges and Streptomyces were identified as functional microbial for the PHA degradation. The microbial communities manifested the co-exclusion under different geological conditions, and played the key role in the soil PHA degradation through amino acid metabolism, energy metabolism and carbohydrate metabolism. The correlation results of amos structural equation showed that the diversity and abundance of soil microorganisms in different regions were controlled by soil PHA content and environmental factors. Altitude, annual average temperature and annual rainfall were positively correlated with microbial diversity. Annual rainfall and soil physical and chemical factors exhibited the most significant influence on it. Microbial diversity indirectly affected the PHA content in different type soil. We believe that reshape the structure and diversity of microbial communities in soil could be changed and reshaped by different geological conditions, pollutants and soil type. This study can provide helps for understanding the ecological effect of geomicrobiology formation under the driving force of geographic environment and other factors.