Microbial ecology of the atmosphere

Abstract

The atmosphere connects habitats across multiple spatial scales via airborne dispersal of microbial cells, propagules, and biomolecules. Atmospheric microorganisms have been implicated in a variety of biochemical and biophysical transformations. Here, we review ecological aspects of airborne microorganisms with respect to their dispersal, activity, and contribution to climatic processes. Latest studies utilizing metagenomic approaches demonstrate that airborne microbial communities exhibit pronounced biogeography, driven by a combination of biotic and abiotic factors. We quantify distributions and fluxes of microbial cells between surface habitats and the atmosphere and place special emphasis on long-range pathogen dispersal. Recent advances have established that these processes may be relevant for macroecological outcomes in terrestrial and marine habitats. We evaluate the potential biological transformation of atmospheric volatile organic compounds and other substrates by airborne microorganisms and discuss clouds as hotspots of microbial metabolic activity in the atmosphere. Furthermore, we emphasize the role of microorganisms as ice nucleating particles and their relevance for the water cycle via formation of clouds and precipitation. Finally, potential impacts of anthropogenic forcing on the natural atmospheric microbiota via emission of particulate matter, greenhouse gases and microorganisms are discussed.

Antimicrobial Resistance in the Environment: Towards Elucidating the Roles of Bioaerosols in Transmission and Detection of Antibacterial Resistance Genes

“…Bioaerosols are representative of their sources and together form a combined sample of multiple origins, although a recent hypothesis tends to support the existence of a specific atmospheric microbiota [ 22 ]. Following transport by bioaerosols, microorganisms can colonize depositional environments, cause infections, or simply decay after settling; additionally, their genetic material (free or within cells) can be transferred throughout the environment.…”

“…The resistome of clouds will also be characterized. Clouds can be considered as an oases for microorganisms, providing them with more favourable conditions such as water or shading against UV radiation [ 22 ]. Such situations can potentially affect their atmospheric transport and, therefore, facilitate the atmospheric dispersion of ARGs worldwide.…”

Distribution and diversity of anaerobic thermophiles and putative anaerobic nickel-dependent carbon monoxide-oxidizing thermophiles in mesothermal soils and sediments

“…An analogous proposal has been presented for anaerobic thermophiles in deep-sea sediments, with ocean currents accounting for the dispersal of spores presumably originating from hydrothermal vents or other heated systems, e.g., Guyamas Basin ( Müller et al, 2014 ). Although these proposals have focused on Firmicutes, they might apply more generally to a wide range of thermophiles, since the troposphere and the oceans represent well known media for short-and long-range transport of phylogenetically diverse taxa originating from numerous sources (e.g., Smith et al, 2013 ; Schmale and Ross, 2015 ; Maki et al, 2019 ; Santl-Temkiv et al, 2022 ).…”

Structure and Protein-Protein Interactions of Ice Nucleation Proteins Drive Their Activity

“…Once, released into the environment, INpro are long lived and can maintain their activity for at least 30,000 years (Creamean et al, 2020). They are found ubiquitously in terrestrial and marine habitats as well as on microbial, plant, fungal and animal surfaces, which all serve as sources for atmospheric INpro (Šantl-Temkiv et al, 2020(Šantl-Temkiv et al, , 2022Huang et al, 2021). INpro are unique in that they can initiate freezing just below 0°C, i.e., close to the melting point of ice (Delort and Amato, 2017;Kanji et al, 2017).…”