甘肃白银铜矿矿坑土壤细菌和古菌的多样性及坡度分布特征

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

摘要:

【背景】甘肃白银铜矿作为西部地区的重要矿区，探究其细菌和古菌多样性及坡度分布特征对明确矿区微生物多样性分布具有关键意义。【目的】通过分析白银铜矿矿坑不同坡度的土壤细菌群落多样性和古菌群落多样性，探究不同坡度土壤样品细菌及古菌多样性与理化性质之间的关系。【方法】以不同坡度的白银铜矿土样为材料，采用Illumina HiSeq测序技术，分析样品的细菌多样性和古菌多样性。【结果】α和β多样性分析表明，ACE、Chao1、Shannon和Simpson等多样性指数在样品间存在显著差异。白银铜矿矿坑土壤的细菌排名前十的纲是Gammaproteobacteria、Oxyphotobacteria、Alphaproteobacteria、Bacteroidia、Actinobacteria、Clostridia、Nitrospira、Bacilli、Mollicutes和Acidimicrobiia，相对丰度最高的是Gammaproteobacteria。在纲水平上，白银铜矿的古菌由Thermoplasmata、Nitrososphaeria、Methanomicrobia、Halobacteria、Methanobacteria、Group_1.1c和Bathyarchaeia组成，相对丰度最高的是Thermoplasmata。冗余分析(redundancy analysis,RDA)得出，pH和速效磷是影响土壤多样性的最重要因素。【结论】白银铜矿为强酸性铜矿，其土壤铜离子含量最高。从坡顶到坡底，pH呈现先降低再升高的趋势(2.18-4.75)，铜离子(20-150mg/kg)和总铁(2.5-50mg/kg)呈现先升高后降低的趋势，铵态氮(3.61-44.90mg/kg)、速效磷(0-56.79mg/kg)和速效钾(9.07-35.65mg/kg)含量低且呈现波动趋势，硫化物(1mg/kg)无明显变化。白银铜矿矿坑土壤细菌相对丰度最高的属为Acidithiobacillus，古菌相对丰度较高的属为uncultured_bacterium_f_Ferroplasmaceae和uncultured_bacterium_f_Nitrososphaeraceae。其中，细菌多样性受到pH驱动，古菌多样性受到速效磷的驱动。本研究有助于我们进一步了解白银铜矿土壤微生物群落的变化。

关键词:白银铜矿矿坑;浸矿微生物;多样性;环境因子

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.

Key words:Baiyin Copper Mine pit;bioleaching microorganisms;diversity;environmental factors