Diversity and slope distribution of bacteria and archaea in the soil of Baiyin Copper Mine pit from Gansu Province

Abstract:

[Background] Gansu Baiyin Copper Mine is an important mining area in western China. It is of great significance to explore the diversity and slope distribution of bacteria and archaea in the area. [Objective] To analyze the community diversity of bacteria and archaea in soil samples at different slopes of Baiyin Copper Mine pit and further the relationship between the diversity and physico-chemical properties of soils. [Methods] Illumina HiSeq was employed to elucidate the diversity of bacteria and archaea in soil samples at different slopes of the pit. [Results] Alpha and beta diversity indices of ACE index, Chao1 index, Shannon index, and Simpson index showed significantly different among samples. The top ten classes of bacteria in the pit included Gammaproteobacteria, Oxyphotobacteria, Alphaproteobacteria, Bacteroidia, Actinobacteria, Clostridia, Nitrospira, Bacilli, Mollicutes, and Acidimicrobiia, among which Gammaproteobacteria was most abundant. At the class level, the archaea of the pit were composed of Thermoplasmata, Nitrososphaeria, Methanomicrobia, Halobacteria, Methanobacteria, Group_1.1c, and Bathyarchaeia, and the abundance of Thermoplasmata was the highest. Redundancy analysis (RDA) suggested that pH and available phosphorus were the major factors affecting soil diversity. [Conclusion] Baiyin Copper Mine is a strong acid mine. The content of copper ions was the highest in soil of Baiyin Copper Mine pit. The pit registered the pH trend of first decreasing and then increasing (2.18-4.75), trends of copper ions (20-150 mg/kg) and total iron (2.5-50 mg/kg) opposite to pH, low contents of ammonium nitrogen (3.61-44.90 mg/kg), available phosphorus (0-56.79 mg/kg), and available potassium (9.07-35.65 mg/kg) with fluctuation, and no obvious variation of sulfide (1 mg/kg) from the surface to the bottom. At the genus level, Acidithiobacillus was most abundant among the bacteria, while the counterparts for archaea were uncultured_bacterium_ f_Ferroplasmaceae and uncultured_bacterium_ f_ Nitrososphaeraceae. pH and available phosphorus were the main factors causing the variation of bacterial and archaeal diversity, respectively. This study is expected to deepen the understanding of changes in soil microbial communities in Baiyin Copper Mine.