pH和水化学类型对内蒙古巴丹吉林沙漠盐湖古菌群落结构的影响

Effects of pH and hydrochemical types on archaeal community structures in salt lakes of Badain Jaran Desert, Inner Mongolia

摘要:

【背景】沙漠湖泊微生物具有独特的群落结构，对于维持沙漠生态平衡和促进生物多样性至关重要。【目的】探究巴丹吉林沙漠盐湖古菌群落结构及其与环境因子的关系。【方法】以巴丹吉林沙漠6个盐湖水体中的古菌群落为研究对象，使用16S rRNA基因扩增子测序技术和生物信息学分析方法，分析古菌群落分布、群落多样性和群落组成；结合水体理化参数，通过Pearson相关性分析、Mantel test和冗余分析(redundancy analysis, RDA)探究环境因子对古菌群落结构的影响。【结果】Piper图显示6个湖泊均为Na⁺-Cl^--CO₃^2-型的盐湖；拟合分析表明古菌群落的Simpson指数、Shannon指数和Pielou指数均与盐度呈线性正相关；盐湖古菌群落隶属于11门17纲25目38科59属，嗜盐古菌门(Halobacteriota)以99%的相对丰度占据绝对主导地位，盐红菌属(Halorubrum)为6个盐湖共有的优势属，属水平上尚存在大量未注释物种；相关性分析表明pH值、Cl^-、CO₃^2-和K⁺浓度显著影响古菌群落α多样性；Mantel test表明pH值、CO₃^2-、Cl^-和K⁺浓度是影响古菌群落属水平物种的重要环境因子；RDA结果表明CO₃^2-浓度显著影响盐湖的古菌群落变化。【结论】巴丹吉林沙漠不同盐湖古菌群落多样性与盐度呈正相关，盐湖古菌群落主要受pH值、CO₃^2-、Cl^-和K⁺浓度的影响，并且存在丰富的新物种资源。

Abstract:

[Background] The microbial communities in desert lakes have unique structures, which are crucial for maintaining the ecological balance and improving the biodiversity in deserts. [Objective] To explore the relationship between archaeal community structures and environmental factors in salt lakes of Badain Jaran Desert. [Methods] The 16S rRNA gene amplicon sequencing and bioinformatics were employed to analyze the distribution, diversity, and structures of archaeal communities in six salt lakes of Badain Jaran Desert. The Pearson correlation analysis, Mantel test, and redundancy analysis (RDA) were performed to explore the effects of environmental factors on archaeal community structures. [Results] Piper diagram showed that the six lakes were all salt lakes of the Na⁺-Cl^--CO₃^2- type. The fitting analysis showed that the Simpson index, Shannon index, and Pielou index of the archaeal community had linearly positive correlations with salinity. The archaea in salt lakes belonged to 59 genera, 38 families, 25 orders, 17 classes of 11 phyla, among which Halobacteriota was absolutely dominant with the relative abundance of 99%. Halorubrum was the dominant genus shared by the six salt lakes, and there were still a large number of unclassified genera. The correlation analysis showed that pH, Cl^-, CO₃^2-,and K⁺significantly affected the alpha diversity of archaeal communities. The Mantel test showed that pH, CO₃^2-, Cl^-, and K⁺ were important environmental factors affecting archaeal genera. The results of RDA showed that CO₃^2- significantly influenced the archaeal community. [Conclusion] The diversity of archaeal communities in different salt lakes of Badain Jaran Desert is positively correlated with salinity, and the archaeal communities in salt lakes are mainly affected by pH, CO₃^2-, Cl^-, and K⁺. In addition, there are abundant unclassified archaeal genera, which indicate the existence of abundant new species resources.