Abstract Wind-blown dust is an important source of trace metals, nutrients, and biological material to montane ecosystems. Mountain ranges in northern Utah are located downwind of multiple dust sources including the Great Basin Desert and the Wasatch Front urban area, providing an opportunity to investigate regional-scale differences in dust deposition chemistry and bacterial composition. We sampled discrete dust layers from snowpack across multiple locations in the Wasatch and Uinta Mountains (Utah) and the Snake Range (Nevada) during spring 2014 and 2015. Dust chemistry was unique in each airshed, suggesting that spatial variability and local sources were more important than temporal variability for the sampling period. The central Wasatch dust contained the highest concentrations of playa-associated elements (U, Mg, Li, Ca, Sr, As) and anthropogenic elements (Sb, Cu, Pb, Se) compared with lowest concentrations of these elements in the northern Wasatch, which is further from playa and anthropogenic sources. Sequential extractions indicate that the majority of Ca, Sr, and Cd is potentially available for transport during snowmelt while other elements are relatively immobile. Central Wasatch dust was more reactive to acetic acid than northern Wasatch dust for most elements, including REE + Y. Sr isotopes (87Sr/86Sr ratios) were also unique to each sampling area, with the most radiogenic values in the central Wasatch. Similar to dust chemistry, bacterial communities in dusty snow reflected geographically localized dust events. In the central Wasatch, 69% of bacterial species were unique, suggesting that the airshed received the most diverse dust inputs from a combination of playa and anthropogenic sources. Gram-positive Actinobacteria and Firmicutes were common in snow but specific bacterial families distinguished airsheds (e.g., Bacillaceae, Geodermatophilaceae, Nakamurellaceae). Our results demonstrate that evaluating dust chemistry and bacteria in snow on a regional scale may more clearly link dust sources to the entrainment of pollutants and seeding of bacteria species to montane systems.

中文翻译：

---

雪中​​的风尘化学和细菌群落是美国犹他州北部空气流域所独有的

摘要 风尘是山地生态系统中微量金属、养分和生物材料的重要来源。犹他州北部的山脉位于大盆地沙漠和瓦萨奇前线市区等多个沙尘源的下风处，为研究沙尘沉积化学和细菌组成的区域尺度差异提供了机会。2014 年和 2015 年春季，我们从 Wasatch 和 Uinta 山脉（犹他州）以及蛇岭（内华达州）的多个地点的积雪中采样了离散的尘埃层。每个空气流域的尘埃化学都是独一无二的，这表明空间变异性和本地来源更为重要而不是采样周期的时间变化。中央瓦萨奇尘埃含有最高浓度的 playa 相关元素（U、Mg、Li、Ca、Sr、As) 和人为元素 (Sb、Cu、Pb、Se) 与这些元素在北部 Wasatch 的最低浓度相比，远离海滩和人为来源。连续提取表明，大部分 Ca、Sr 和 Cd 可能在融雪期间可用于运输，而其他元素则相对固定。对于包括 REE + Y 在内的大多数元素，中央 Wasatch 灰尘对乙酸的反应性高于北部 Wasatch 灰尘。每个采样区域的 Sr 同位素（87Sr/86Sr 比率）也是独一无二的，中部 Wasatch 的放射性值最高。与尘埃化学类似，尘土飞扬的雪中的细菌群落反映了地理上局部的尘埃事件。在瓦萨奇中部，69% 的细菌种类是独一无二的，这表明空气流域从海滩和人为来源的组合中获得了最多样化的灰尘输入。革兰氏阳性放线菌和厚壁菌在雪中很常见，但特定的细菌家族区分了气域（例如，芽孢杆菌科、土皮病菌科、Nakamurellaceae）。我们的结果表明，在区域范围内评估雪中的灰尘化学和细菌可以更清楚地将灰尘源与污染物的夹带和细菌物种的播种联系到山地系统。