巴里坤盐湖退化区土壤微生物群落结构及生态功能分析

Community structure and ecological functions of soil microorganisms in the degraded area of Barkol Lake

摘要:

【目的】微生物是湖泊生态系统的重要组成部分，参与碳、氮和硫等元素的生物地球化学循环过程，其群落组成和功能对环境的稳定性和可持续性至关重要。然而，新疆的部分湖泊出现退化和盐渍化等问题，微生物如何响应湖泊退化值得研究。【方法】本研究基于16S rRNA基因的扩增子高通量测序，对巴里坤盐湖退化区域的土壤微生物群落结构进行分析，同时对微生物的潜在生态学功能进行预测。【结果】本研究发现，假单胞菌门(Pseudomonadota)、绿弯菌门(Chloroflexota)和拟杆菌门(Bacteroidota)是巴里坤盐湖退化生境中的优势类群。在轻度退化阶段，脱硫菌门(Desulfobacterota)和弯曲杆菌门(Campylobacterota)是主要类群，但随着湖泊退化程度加剧，这些类群急剧减少甚至消失；在极度退化阶段，酸杆菌门(Acidobacteriota)和浮霉菌门(Planctomycetota)等类群逐渐占据主导地位。基于BugBase对氧的需求进行预测，结果发现好氧类群主要是放线菌门(Actinomycetota)、假单胞菌门(Pseudomonadota)和绿弯菌门(Chloroflexota)等，且大多分布在重度退化阶段；而厌氧类群则主要是假单胞菌门(Pseudomonadota)、拟杆菌门(Bacteroidota)和酸杆菌门(Acidobacteriota)等，且主要分布在轻度退化阶段。利用FAPROTAX对不同区域微生物类群的生态学功能进行预测，结果表明，随着湖泊退化过程的加剧，由微生物主导的硫酸盐呼吸过程、发酵过程，以及烃降解过程逐渐减弱，但硝化作用逐渐加强。【结论】巴里坤盐湖退化区域的微生物多样性丰富，并且主导了多个生物地球化学循环过程，随着湖泊退化程度加深，微生物生态位逐渐改变。本研究为巴里坤盐湖微生物资源多样性的保育及开发利用提供了重要的理论基础。

Abstract:

[Objective] As an important part of lake ecosystem, microorganisms play an essential role in the biogeochemical cycle of carbon, nitrogen, sulfur, and other elements, and the community structure and functions of them are crucial to environmental stability and sustainability. However, the lakes in Xinjiang are degraded and salinized, and how microorganisms respond to the degradation is unclear. [Methods] The 16S rRNA gene amplicon sequencing was performed to analyze the soil microbial community structure of the degraded area of Barkol Lake and the potential ecological functions of the microorganisms were predicted. [Results] Pseudomonadota, Chloroflexota, and Bacteroidota dominated different parts in the degraded area. In addition, the abundance of Desulfobacterota and Campylobacterota was the highest in the mildly degraded part of the lake, but the two drastically decreased and even disappeared as the degradation aggravated. The extremely degraded part was dominated by Acidobacteriota, Planctomycetota,etc. According to the oxygen utilization predicted by BugBase, the aerobic groups were mainly Actinomycetota, Pseudomonadota, and Chloroflexota, and the majority of them were in the severely degraded part. Moreover, the anaerobic groups were Pseudomonadota, Bacteroidota, and Acidobacteriota, which were mainly in the mildly degraded part. FAPROTAX was employed for predicting the ecological relevant functions of microorganisms in different parts of the degraded area and the result suggested the weakened sulfate respiration, fermentation, and hydrocarbon degradation, and the enhanced nitrification of microorganisms with the aggravation of degradation. [Conclusion] Microorganisms show high diversity in the degraded area of Barkol Lake, which dominate multiple biogeochemical cycles. As the degradation becomes serious, the microbial niche changes. This study lays a theoretical basis for the rational development and utilization of microbial resources in Barkol Lake.