和田市大气颗粒物细菌群落结构及影响因素

Bacterial Community Structure and Influencing Factors of Airborne Particulate Matter in Hotan City

文章采集极干旱区域和田市城区2020年1月(非沙尘)和2020年7月(沙尘)2个不同时期的可吸入颗粒物(PM_(2.5)和PM_(10)),并采用离子色谱法和高通量测序法分别分析可吸入颗粒物中水溶性离子和细菌群落组成。结果表明,和田市城区PM_(2.5)质量浓度越高,可吸入颗粒物中细菌丰富度和多样性越低,而PM_(10)质量浓度越高,可吸入颗粒物中细菌丰富度和多样性越高;变形菌门(PM_(2.5):沙尘43.5%和非沙尘32.6%,PM_(10):沙尘33.9%和非沙尘45.4%)和厚壁菌门(PM_(2.5):沙尘22.7%和非沙尘28.5%,PM_(10):沙尘23.8%和非沙尘17.3%)是大气颗粒物中最丰富的细菌,不动杆菌属(PM_(2.5):沙尘16.2%和非沙尘7.2%,PM_(10):沙尘9.2%和非沙尘13.9%)是大气颗粒物中优势细菌属。冗余分析结果显示,温度和Ca2+对细菌群落结构分布有较大影响。气团轨迹结果表明,非沙尘期500 m气团来源于城区较近的塔克拉玛干沙漠,1 000 m和1 500 m高度时,气团来源于中国周边国家;沙尘期气团都经过塔克拉玛干沙漠。

In this study, inhalable particulate matter(PM_(2.5)and PM_(10)) were collected in two different periods from the urban area of Hotan City in the extremely arid region in January 2020(nondust)and July 2020(dust), and the water-soluble ions and bacterial community composition were detected by ion chromatography and high-throughput sequencing, respectively.The results showed that the higher the PM_(2.5)mass concentration in the urban area of Hotan, the lower the bacterial richness and diversity in PM_(10)particles, while the higher the PM_(10)mass concentration, the higher the bacterial richness and diversity in PM_(10)particles. Proteobacteria(PM_(2.5):dust 43.5% and nondust 32.6%,PM_(10):dust 33.9% and nondust 45.4%)and Firmicutes(PM_(2.5):dust 22.7% and nondust 28.5%,PM_(10):dust 23.8% and nondust 17.3%)were the most abundant bacteria in atmospheric particulates. Acinetobacter(PM_(2.5):dust 16.2% and nondust 7.2%,PM_(10):dust 9.2% and nondust 13.9%)was the dominant bacteria in atmospheric particulates. The results of redundancy analysis showed that temperature and Ca2+had great influence on the bacterial community structure. The results show that the air mass at 500 m in nondust period originated from the Taklimakan Desert near the urban area, and at 1 000 m and 1 500 m, the air mass originated from the surrounding countries of China. The dust period air mass passes through the Taklimakan Desert.