Deposition of Sahara dust (SD) particles is a frequent phenomenon in Europe, but little is known about the viability and composition of the bacterial community transported with SD. The goal of this study was to characterize SD-associated bacteria transported to the European Alps, deposited and entrapped in snow. During two distinct events in February and May 2014, SD particles were deposited and promptly covered by falling snow, thus preserving them in distinct ochre layers within the snowpack. In June 2014, we collected samples at different depths from a snow profile at the Jungfraujoch (Swiss Alps; 3621 m a.s.l.). After filtration, we performed various microbiological and physicochemical analyses of the snow and dust particles therein that originated in Algeria. Our results show that bacteria survive and are metabolically active after the transport to the European Alps. Using high throughput sequencing, we observed distinct differences in bacterial community composition and structure in SD-layers as compared to clean snow layers. Sporulating bacteria were not enriched in the SD-layers; however, phyla with low abundance such as Gemmatimonadetes and Deinococcus-Thermus appeared to be specific bio-indicators for SD. Since many members of these phyla are known to be adapted to arid oligotrophic environments and UV radiation, they are well suited to survive the harsh conditions of long-range airborne transport.
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机译:在欧洲,撒哈拉尘埃(SD)颗粒的沉积是一种常见现象,但是对于用SD运送的细菌群落的生存能力和组成知之甚少。这项研究的目的是鉴定与标清相关的细菌,这些细菌被运输到欧洲阿尔卑斯山,沉积并积存在雪中。在2014年2月和2014年5月的两次不同事件中,SD颗粒沉积并迅速被降雪覆盖,因此将它们保存在雪堆中不同的o石层中。 2014年6月,我们从少女峰(瑞士阿尔卑斯山; 3621 m a.s.l.)的积雪中收集了不同深度的样本。过滤后,我们对源自阿尔及利亚的雪和尘埃颗粒进行了各种微生物学和理化分析。我们的结果表明,细菌在运输到欧洲阿尔卑斯山后仍存活并具有代谢活性。使用高通量测序,我们观察到与清洁雪层相比,SD层中细菌群落组成和结构存在明显差异。产孢细菌未富集在SD层中。然而,诸如Gemmatimonadetes和Deinococcus-Thermus的丰度低的门似乎是SD的特定生物指标。由于已知这些门的许多成员都适合干旱贫营养环境和紫外线辐射,因此它们非常适合在远程空中运输的恶劣条件下生存。
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