Global airborne microbial communities controlled by surrounding landscapes and wind conditions

Abstract

The atmosphere is an important route for transporting and disseminating microorganisms over short and long distances. Understanding how microorganisms are distributed in the atmosphere is critical due to their role in public health, meteorology and atmospheric chemistry. In order to determine the dominant processes that structure airborne microbial communities, we investigated the diversity and abundance of both bacteria and fungi from the PM10 particle size (particulate matter of 10 micrometers or less in diameter) as well as particulate matter chemistry and local meteorological characteristics over time at nine different meteorological stations around the world. The bacterial genera Bacillus and Sphingomonas as well as the fungal species Pseudotaeniolina globaosa and Cladophialophora proteae were the most abundant taxa of the dataset, although their relative abundances varied greatly based on sampling site. Bacterial and fungal concentration was the highest at the high-altitude and semi-arid plateau of Namco (China; 3.56 × 106 ± 3.01 × 106 cells/m3) and at the high-altitude and vegetated mountain peak Storm-Peak (Colorado, USA; 8.78 × 104 ± 6.49 × 104 cells/m3), respectively. Surrounding ecosystems, especially within a 50 km perimeter of our sampling stations, were the main contributors to the composition of airborne microbial communities. Temporal stability in the composition of airborne microbial communities was mainly explained by the diversity and evenness of the surrounding landscapes and the wind direction variability over time. Airborne microbial communities appear to be the result of large inputs from nearby sources with possible low and diluted inputs from distant sources.

Microbial functional signature in the atmospheric boundary layer

“…CC BY 4.0 License. different local sources were upwind (Tignat-Perrier et al, 2019). Our results did not show a specific (metabolic) functional potential signature for the atmosphere, which was rather mainly driven by the surrounding landscapes.…”

“…Microorganisms are ubiquitous in the atmosphere and reach concentrations of up to 10 6 microbial cells per cubic meter of air (Tignat-Perrier et al, 2019). Due to their important roles in public health and meteorological processes (Ariya et al, 2009;Aylor, 2003;Brown and Hovmøller, 2002;Delort et al, 2010;Griffin, 2007), understanding how airborne microbial communities are distributed over time and space is critical.…”

“…Due to their important roles in public health and meteorological processes (Ariya et al, 2009;Aylor, 2003;Brown and Hovmøller, 2002;Delort et al, 2010;Griffin, 2007), understanding how airborne microbial communities are distributed over time and space is critical. While the concentration and taxonomic diversity of airborne microbial communities in the planetary boundary layer have recently been described (Els et al, 2019;Innocente et al, 2017;Tignat-Perrier et al, 2019), the functional potential of airborne microbial communities remains unknown. Most studies have focused on laboratory cultivation to identify possible metabolic functions of microbial strains of atmospheric origin, mainly from cloud water (Amato et al, 2007;Ariya et al, 2002;Hill et al, 2007;Vaïtilingom et al, 2010Vaïtilingom et al, , 2013.…”

“…The number of fungal and bacterial cells was also estimated using 16S rRNA and 18S rRNA gene copy numbers per cubic meter of air, respectively. qPCR results on air samples are available inTignat-Perrier et al, 2019. Air samples had ratios between bacterial cell and fungal cell concentrations from around 4.5 times up to 160 times lower than soil samples(Table S4).…”

Atmospheric Biodetection Part I: Study of Airborne Bacterial Concentrations from January 2018 to May 2020 at Saclay, France

“…Therefore, the origin of atmospheric bacteria measured at Saclay is mostly continental, which is in accordance with what has been reported by the authors of [ 23 , 24 ]. The results of the model agree very well with what has been observed by the authors of [ 95 , 96 ], both in terms of seasonality and of daily variability. It underlines the strong capacity of the surrounding ecosystem to generate epiphytic and telluric bacteria (see Figure A2 ).…”