Els Nora, Greilinger Marion, Reisecker Michael, Tignat-Perrier Romie, Baumann-Stanzer Kathrin, Kasper-Giebl Anne, Sattler Birgit, Larose Catherine
Institute of Ecology, University of Innsbruck, Innsbruck, Austria.
Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna, Austria.
Front Microbiol. 2020 May 20;11:980. doi: 10.3389/fmicb.2020.00980. eCollection 2020.
We investigated the interactions of air and snow over one entire winter accumulation period as well as the importance of chemical markers in a pristine free-tropospheric environment to explain variation in a microbiological dataset. To overcome the limitations of short term bioaerosol sampling, we sampled the atmosphere continuously onto quartzfiber air filters using a DIGITEL high volume PM10 sampler. The bacterial and fungal communities, sequenced using Illumina MiSeq, as well as the chemical components of the atmosphere were compared to those of a late season snow profile. Results reveal strong dynamics in the composition of bacterial and fungal communities in air and snow. In fall the two compartments were similar, suggesting a strong interaction between them. The overlap diminished as the season progressed due to an evolution within the snowpack throughout winter and spring. Certain bacterial and fungal genera were only detected in air samples, which implies that a distinct air microbiome might exist. These organisms are likely not incorporated in clouds and thus not precipitated or scavenged in snow. Although snow appears to be seeded by the atmosphere, both air and snow showed differing bacterial and fungal communities and chemical composition. Season and alpha diversity were major drivers for microbial variability in snow and air, and only a few chemical markers were identified as important in explaining microbial diversity. Air microbial community variation was more related to chemical markers than snow microbial composition. For air microbial communities Cl, TC/OC, SO , Mg, and Fe/Al, all compounds related to dust or anthropogenic activities, were identified as related to bacterial variability while dust related Ca was significant in snow. The only common driver for snow and air was SO , a tracer for anthropogenic sources. The occurrence of chemical compounds was coupled with boundary layer injections in the free troposphere (FT). Boundary layer injections also caused the observed variations in community composition and chemistry between the two compartments. Long-term monitoring is required for a more valid insight in post-depositional selection in snow.
我们研究了整个冬季积雪期空气与雪之间的相互作用，以及原始自由对流层环境中化学标志物对解释微生物数据集变化的重要性。为克服短期生物气溶胶采样的局限性，我们使用DIGITEL大容量PM10采样器将大气连续采样到石英纤维空气过滤器上。将使用Illumina MiSeq测序的细菌和真菌群落以及大气中的化学成分与晚季雪剖面的进行比较。结果揭示了空气和雪中细菌和真菌群落组成的强烈动态变化。秋季，这两个部分相似，表明它们之间存在强烈的相互作用。随着季节的推进，由于整个冬季和春季积雪层内部的演变，重叠部分减少。某些细菌和真菌属仅在空气样本中被检测到，这意味着可能存在独特的空气微生物群落。这些生物体可能未被纳入云层，因此不会在雪中沉淀或清除。尽管雪似乎是由大气播种的，但空气和雪都显示出不同的细菌和真菌群落以及化学成分。季节和α多样性是雪和空气中微生物变异性的主要驱动因素，并且仅确定了少数化学标志物对解释微生物多样性很重要。空气微生物群落变化比雪微生物组成与化学标志物的关系更大。对于空气微生物群落，Cl、TC/OC、SO、Mg和Fe/Al，所有与灰尘或人为活动相关的化合物，都被确定与细菌变异性有关，而与灰尘相关的Ca在雪中具有显著性。雪和空气唯一的共同驱动因素是SO，它是人为来源的示踪剂。化合物的出现与自由对流层（FT）中的边界层注入有关。边界层注入还导致了两个部分之间观察到的群落组成和化学变化。需要进行长期监测才能更有效地了解雪中沉积后选择情况。
