Metagenomic Analysis of Microbial Diversity in the Urban Air of Sofia (Bulgaria) during Spring and Winter

Abstract

The main scientific interest for decades remained focused primarily on physical and chemical air pollutants, which severely limited our knowledge of microbial diversity in the atmosphere. The ecology of airborne microorganisms is poorly understood, even though they are a constant element of the air we breathe. Their exploration is very important for understanding health and ecological impacts, mainly in the highly urbanized cities. The main purpose of this study is to explore the biodiversity of microorganisms in the atmosphere over the densely populated centre of Sofia (Bulgaria) during spring and winter by Next-generation sequencing. The results showed that the most prevailing bacteria in the urban bioaerosols were representatives of phyla Firmicutes, Proteobacteria, Bacteroides, Actinobacteria. Many of the identified species were soil and leaf  surface dwellers. Most of the detected fungal sequences belong to the phylum Ascomycota. Some pathogenic bacterial and fungal taxa were also found. This study provides the first information about microbial diversity in the outdoor air above Sofia and contributes to better understanding of urban airborne microbiota.