(Table 1) Geographical location and nutrient composition of saline lake sediments (SLS) and nearby adjacent biological soil crusts (BSC) identified as potential dust sources

While microbial communities of aerosols have been examined, little is known about their sources. Nutrient composition and microbial communities of potential dust sources, saline lake sediments (SLS) and adjacent biological soil crusts (BSC), from Southern Australia were determined and compared with a previously analyzed dust sample. Multivariate analyses of fingerprinting profiles indicated that the bacterial communities of SLS and BSC were different, and these differences were mainly explained by salinity. Nutrient concentrations varied among the sites but could not explain the differences in microbial diversity patterns. Comparison of microbial communities with dust samples showed that deflation selects against filamentous cyanobacteria, such as the Nostocales group. This could be attributed to the firm attachment of cyanobacterial filaments to soil particles and/or because deflation occurs mainly in disturbed BSC, where cyanobacterial diversity is often low. Other bacterial groups, such as Actinobacteria and the spore-forming Firmicutes, were found in both dust and its sources. While Firmicutes-related sequences were mostly detected in the SLS bacterial communities (10% of total sequences), the actinobacterial sequences were retrieved from both (11–13%). In conclusion, the potential dust sources examined here show highly diverse bacterial communities and contain nutrients that can be transported with aerosols. The obtained fingerprinting and sequencing data may enable back tracking of dust plumes and their microorganisms.

虽然气溶胶中的微生物群落已被研究，但人们对其来源知之甚少。本研究测定了澳大利亚南部潜在沙尘来源——盐湖沉积物（saline lake sediments, SLS）及邻近生物土壤结皮（biological soil crusts, BSC）的营养成分和微生物群落，并与先前分析的沙尘样本进行比较。指纹图谱的多变量分析表明，SLS和BSC的细菌群落存在差异，且这些差异主要由盐度解释。不同位点的营养浓度存在差异，但无法解释微生物多样性模式的差异。微生物群落与沙尘样本的比较显示，风蚀对丝状蓝细菌（如念珠藻目群）具有选择排斥作用。这可能归因于蓝细菌丝状体与土壤颗粒的牢固附着，以及/或风蚀主要发生在受干扰的BSC中（此类BSC的蓝细菌多样性通常较低）。其他细菌类群（如放线菌门和产孢厚壁菌门）在沙尘及其来源中均有发现。尽管厚壁菌门相关序列主要在SLS细菌群落中检测到（占总序列的10%），但放线菌门序列在两者中均有检出（11–13%）。综上，本研究检测的潜在沙尘来源具有高度多样的细菌群落，并含有可随气溶胶传输的营养物质。获得的指纹图谱和测序数据或可实现尘羽及其微生物的溯源。