Dust

storms transport entire Saharan microbial communities to the Alps

To move from the Saharan desert to the Dolomites would not be an easy task for anyone. However, due to climate change and land use we are witnessing increasingly frequent episodes of microbial migrations from the Sahara to areas with very different climatic conditions than those in their place of origin. In February 2014, an extremely rare event occurred, known as a ‘pink snowfall’, when large amounts of snow containing Saharan sand fell on the Alps, leaving summits ‘painted in pink’. Thanks to successive snowfalls, the deposited sand remained sealed and frozen for months in layers of clean snow. However, this sand is not inanimate. The peculiarity of the event and the natural preservation of the samples provided researchers with a unique opportunity to study the microbiological load of the sand using advanced genetic analyses. In the samples collected on the Marmolada and Latemar, a multidisciplinary team of microbiologists, geologists, chemists and bioclimatologists from the Fondazione Edmund Mach, Institute of Biometeorology of the National Research Council, Universities of Florence, Venice and Innsbruck discovered that large dust storms can move entire microbial communities from the Saharan areas to Europe, and that this microbiota is rich in many extremely resistant organisms capable of surviving in different environments. By comparing the DNA sequences from the frozen bacteria and fungi, to those from local soil microbial communities, the researchers also found that some of the Saharan microbes can persist in the alpine soil even after the snow has melted. This suggests that, with climate change and the subsequent increasing frequency of events like the one studied, the microbial communities of our soils could significantly change. The study published in the prestigious journal Microbiome paves the way for new research areas in the field of microbiology and has been listed as a ‘success’ by Research Italy (MIUR) and highlighted by the World Meteorological Organization (WMO), in national and international news bulletins, and widely read internet platforms.