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Saharan microbial communities on the Alps

In Microbiome a study by Unifi, the National Research Council and the Edmund Mach Foundation
Climate change and land use are causing migrations that cannot be stopped: those of microorganisms. A multidisciplinary team of microbiologists, geologists, chemists and bioclimatologists from the University of Florence, the Edmund Mach Foundation of San Michele all'Adige (FEM), the Institute of Biometeorology of the National Research Council, the universities of Venice and Innsbruck, studied the microbial community resulting from one of the most intense transport events of Saharan dust that reached the Alps in 2014, publishing the results in the prestigious journal Microbiome ( "Legal immigrants: invasion of alien microbial communities during winter occurring desert dust storms" doi: 10.1186 / s40168 -017-0249-7)

The great storm that occurred three years ago deposited huge amounts of Saharan dust on the Dolomite Alps, which was then sealed between layers of "clean" snow. This enabled a precise determination of the microorganisms associated with the deposition.

In snow samples collected on the Marmolada and Latemar, the researchers found evidence that large dust storms can move not only fractions, but entire microbial communities (bacteria and fungi) from the Saharan areas towards Europe and that such microbiota contains many organisms which are extremely resistant and able to survive in different environments.

The interdisciplinary team was led by Duccio Cavalieri (University of Florence), Tobias Weil (FEM) and Franco Miglietta (CNR-IBIMET, FOXLAB) who, together, coordinated experts in geology, environment, meteorology, microbiology and bioinformatics Edmund Mach Foundation, National Council research, University of Florence, Innsbruck, Venice.

"The idea of ​​studying a unique winter event," the scientists explain, "made it possible to discover almost entire communities of Saharan microbes, carried by wind and frozen in a layer of pink snow, kept isolated below zero by the previous and subsequent layers." The analysis of genetic imprints of frozen bacteria and fungi and of soil microbial communities, made it possible to verify that some of these Saharan microbes survive even after the snow has melted, probably because they are present in large quantities.

These findings suggest that climate change and the increasing frequency of these events can significantly change the microbial communities of our soils, moving entire microbial communities far away from their origins.

Accepting the challenge recently launched by the United Nations for the implementation of monitoring and protection activities in the field of sand and dust storms that cause long-range transport, the authors indicate rapid and effective methods to monitor the risks associated with the melting of snow and glaciers contaminated by microbial populations that arrive from afar. It is one way to develop effective early warning systems.

The study was made possible by modern and sophisticated research instruments: these include the metagenomic and FEM computational biology. "Since the latest generation sequencing techniques have given man the ability to see without cultivating microorganisms on a plate, but identifying them directly from the 'imprint' of the DNA, it was discovered that bacteria and fungi are present in all environments, including air, the clouds and the wind," conclude the researchers. 

30 March 2017