Exposure to airborne bacteria depends upon vertical stratification and vegetation complexity

Abstract

Exposure to biodiverse aerobiomes supports human health, but it is unclear which ecological factors influence exposure. Few studies have investigated near-surface green space aerobiome dynamics, and no studies have reported aerobiome vertical stratification in different urban green spaces. We used columnar sampling and next generation sequencing of the bacterial 16S rRNA gene, combined with geospatial and network analyses to investigate urban green space aerobiome spatio-compositional dynamics. We show a strong effect of habitat on bacterial diversity and network complexity. We observed aerobiome vertical stratification and network complexity that was contingent on habitat type. Tree density, closer proximity, and canopy coverage associated with greater aerobiome alpha diversity. Grassland aerobiomes exhibited greater proportions of putative pathogens compared to scrub, and also stratified vertically. We provide novel insights into the urban ecosystem with potential importance for public health, whereby the possibility of differential aerobiome exposures appears to depend on habitat type and height in the airspace. This has important implications for managing urban landscapes for the regulation of aerobiome exposure.

An Overview of Environmental Risk Factors for Food Allergy

“…Yet, on the other hand, sufficiently high levels of vegetation could also reduce UVB radiation exposure as the tree canopy can block out sunlight. Diversity of environmental microbiota is also related to vegetation levels [ 86 , 87 ]. Pollen requires the presence of vegetation and therefore, vegetation can determine levels of pollen exposure.…”

Reciprocal Inclusion of Microbiomes and Environmental Justice Contributes Solutions to Global Environmental Health Challenges

“…Important health benefits associated with access to green spaces include improved mental and physical health and long-term reduction in mortality ( 32 – 34 ). Environmental microbiome exposures in green spaces relate to similar health benefits ( 35 – 37 ), and conversely, the biodiversity hypothesis suggests that reduction of environmental microbial exposures negatively impacts human health ( 38 ).…”

“…Microbiome stewardship benefits human and non-human entities. For example, incorporating beneficial microbial exposure as a feature of urban landscape design supports community health ( 35 – 37 ). In agroecosystems, intensive agriculture and land management practices that contribute to soil erosion and nutrient loss are linked to detrimental human health outcomes ( 100 ).…”

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“…Furthermore, studies looking at the effects of the aerobiome (the collection of microorganisms in a given airspace) on murine models have shown that it affects their guts’ microbial composition, short-chain fatty acid production, and has anxiolytic effects ( 45 ). Also, evidence shows vertical stratification of the vegetation in greenspaces influences the aerobiome composition, with potential implications for human health ( 46 ).…”