Landscape Topography and Regional Drought Alters Dust Microbiomes in the Sierra Nevada of California

Abstract

Dust provides an ecologically significant input of nutrients, especially in slowly eroding ecosystems where chemical weathering intensity limits nutrient inputs from underlying bedrock. In addition to nutrient inputs, incoming dust is a vector for dispersing dust-associated microorganisms. While little is known about dust-microbial dispersal, dust deposits may have transformative effects on ecosystems far from where the dust was emitted. Using molecular analyses, we examined spatiotemporal variation in incoming dust microbiomes along an elevational gradient within the Sierra Nevada of California. We sampled throughout two dry seasons and found that dust microbiomes differed by elevation across two summer dry seasons (2014 and 2015), which corresponded to competing droughts in dust source areas. Dust microbial taxa richness decreased with elevation and was inversely proportional to dust heterogeneity. Likewise, dust phosphorus content increased with elevation. At lower elevations, early season dust microbiomes were more diverse than those found later in the year. The relative abundances of microbial groups shifted during the summer dry season. Furthermore, mutualistic fungal diversity increased with elevation, which may have corresponded with the biogeography of their plant hosts. Although dust fungal pathogen diversity was equivalent across elevations, elevation and sampling month interactions for the relative abundance, diversity, and richness of fungal pathogens suggest that these pathogens differed temporally across elevations, with potential implications for humans and wildlife. This study shows that landscape topography and droughts in source locations may alter the composition and diversity of ecologically relevant dust-associated microorganisms.

Respirable Metals, Bacteria, and Fungi during a Saharan–Sahelian Dust Event in Houston, Texas

“…Future research also needs to complement metagenomically identified bacteria and fungi by monitoring culturability to better assess microorganisms’ role in ecosystem, human, plant, and animal health. ,,,,− Such studies should also measure other water-soluble aerosol components and metal speciation, some of which might affect viability. Additionally, airborne pollutants have the capacity to influence aerobiome abundance, diversity, transport, and deposition, and conversely, bioaerosols can facilitate the transport and deposition of airborne pollutants. , The interplay between bioaerosols and anthropogenic emissions is complex and dependent on multiple factors, including pollutant type, concentration levels, and meteorological parameters.…”

Aerosolized Desert Dusts Collected Near a Drying Lake and Pulmonary Inflammation in Mice: Implications for Environmental Exposures and Asthma

“…At each of four sites, we collected dust using passive collectors; our collectors consisted of a modified round bundt pan (Nordic Ware, Minneapolis, MN, USA) coated with Teflon (25.4 cm in diameter), which was lined with Kevlar mesh (Industrial Netting, Maple Grove, MN, USA), as described in Aciego et al (2017) 24 and Maltz et al (2022). 25 Glass marbles were suspended from the bottom and rested atop the mesh within the pan. Pans were fitted with overarching cross-braced strapping, which was covered in bird repellent (Bird-X, Elmhurst, IL, USA) to deter bird visitation or roosting.…”