红壤地下水厌氧氨氧化菌分布特征及环境响应

Distribution characteristics and environmental responses of anammox bacteria in groundwater of red soil areas

【目的】进一步了解红壤区地下水中厌氧氨氧化菌群落结构分布规律及其生态功能差异化机制。【方法】以酸性红壤地下水为研究对象,结合理化指标和微生物高通量测序技术,研究吉安市地下水中微生物群落结构和厌氧氨氧化菌的分布规律及其影响因子。【结果】11个地下水研究点中,氮含量超标点位有3个,超标率达27.3%;仅有2个站点的水质符合《生活饮用水卫生标准》(GB 5749—2022)要求,超标率达81.8%。地下水中厌氧氨氧化菌广泛存在,11个样品的厌氧氨氧化细菌hzsB基因拷贝数在3.67×10^(4)−6.62×10^(8) copies/g,与其他生态系统相比,红壤地下水厌氧氨氧化菌功能基因拷贝数更高,说明地下水环境特性更适合厌氧氨氧化细菌生长代谢。每个点位均检测出厌氧氨氧化菌的4个属:Candidatus Brocadia为优势菌属,平均丰度值为62.47%,Candidatus Scalindua平均丰度值为17.44%,Candidatus Jettenia平均丰度值为14.41%,Candidatus Kuenenia平均丰度值为5.67%。相关性分析表明,厌氧氨氧化菌基因丰度与氨氮、锰、氯化物相关性显著,可见地下水中氨氮、锰、氯化物含量的升高可能会增强厌氧氨氧化菌的活性及丰度。【结论】本研究结果突出了厌氧氨氧化菌对红壤地下水元素地球化学生物循环的重要价值,可为我国红壤区地下水污染的生物防治技术的研究提供基础资料。

[Objective]To further understand the community structure,distribution,and ecological function differentiation mechanism of anammox bacteria in the groundwater of red soil areas.[Methods]We employed physical and chemical tests and high-throughput sequencing to study the microbial community structure,distribution of anammox bacteria,and their influencing factors in the groundwater of Ji’an.[Results]The nitrogen content exceeded the limit at three sites among the 11 groundwater sampling sites,with an over-limit rate of 27.3%.The water quality of only two sites met the requirements of the Standard for Drinking Water Quality(GB 5749—2022),which indicated an over-limit rate of 81.8%.Anammox bacteria presented wide distribution in groundwater,and the abundance of hzsB gene in the 11 samples ranged from 3.67×10^(4) copies/g to 6.62×10^(8 )copies/g.Compared with other habitats,the groundwater in red soil areas showed increased copy number of functional genes of anammox bacteria,which indicated that the environmental characteristics of groundwater were more suitable for the growth and metabolism of anammox bacteria.Four genera of anammox bacteria were detected at each site.Specifically,Candidatus Brocadia,Candidatus Scalindua,Candidatus Jettenia,and Candidatus Kuenenia showed the average abundance of 62.47%,17.44%,14.41%,and 5.67%,respectively.The correlation analysis suggested that the gene abundance of anammox bacteria was significantly correlated with ammonia nitrogen,manganese,and chloride,which indicated that the increases in ammonia nitrogen,manganese,and chloride in groundwater may enhance the activity and abundance of anammox bacteria.[Conclusion]The results of this study highlight the importance of anammox bacteria in the geochemical and biological cycling of elements in the groundwater of red soil areas,which will provide basic data for the bioremediation of groundwater pollution in the red soil areas of China.