研究发现，与尘埃有关的空气传播的微生物的可变性提示，地理位置、气候与土壤条件可能影响空气传播的微生物群落的组成。尽管长久以来人们知道大气中存在细菌和真菌，以及可能的长距离大气运输，大陆尺度的微生物群落空间变化尚未得到评估。为了测绘空气传播的微生物多样性，Noah Fierer 及其同事收集了来自美国各地超过1200所住宅的外表面的尘样本，然后评估了存在的细菌与真菌物种。尽管微生物群落组成具有高度的空间可变性，沿海地区有类似的空气传播群落，这提示气候与土壤因素可能解释其中的某些变化。枝孢属(Cladosporium)是一个真菌属，它是常见的过敏原，在美国中西部与东部等湿润地区丰富存在。没有发现城市尘埃含有不同于农村尘埃的群落，但是城市尘埃表现出的变化性少于农村尘埃，这提示城市化可能导致空气传播的微生物群落的均匀化。这组作者说，这些结果提示，关于空气传播的微生物的大陆分布的信息可能有助于识别出空气传播的微生物与疾病之间的联系。

    原文链接：Continental-scale distributions of dust-associated bacteria and fungi

    原文摘要：We inhale thousands of microbial cells when we breathe in outdoor air, and some of these airborne microbes can serve as pathogens or triggers of allergic disorders. Using settled dust samples from ∼1,200 locations, we generated the first atlas, to our knowledge, of airborne bacterial and fungal distributions across the continental United States. We found that airborne microbial communities, such as terrestrial plants and animals, exhibit nonrandom geographic patterns, and we identified the factors that shape the continental-scale distributions of microbial taxa. Furthermore, we found that the airborne microbes found in urban and more rural areas are not distinct in composition, but the dust-associated communities found in more urbanized areas are more homoGENEous across the United States.