Fungus above us: Eco-environmental drivers of fungal diversity and transport in the atmosphere

Fungi are among the most important biota on the planet, mediating ecosystem processes and contributing to the global bioaerosol budget and pollution even when metabolically inactive. Despite this, diversity and transport of fungi in the atmosphere are poorly explored. Here I show that the atmosphere contains diverse fungi with varied ecological roles and recruitment reflecting underlying habitats. The atmospheric mycobiome is dominated by decomposers and pathogens; over 40% of the total airborne mycobiota are known pathogens of plants or animals, including humans, with the capacity to transfer antibiotic resistance genes. Using aircraft surveys between 2022-2023 and unprecedented comprehensive environmental datasets, I found that remote sensing and meteorological data can predict diversity of fungi comprising the rare/transient portion of the atmospheric mycobiome. Vegetative decay/turnover is linked to increased fungal richness in the atmosphere, strengthening the view that phenology is a major determinant of atmospheric biodiversity. Additionally, ecological selection and niche effects can shape vertical assembly of the atmospheric mycobiome. Forward trajectory models predict air masses carrying the sampled fungi will reach Africa, Europe, and Asia as far as east as Kazakhstan, with global impacts and long-range transport beyond 11,000-km possible. This work sheds light on how genomic and environmental datasets acquired by aircraft and satellites can be used for multipronged data forecasts and dispersal predictions to allow proactive measures, clarify aerobiology questions, and provide a unified view of fungal ecology for planetary protection.