Seasonal variability in airborne bacterial communities at a high-elevation site

• Published in: Atmospheric environment (1994) 2012-04, Vol.50, p.41-49
• Main Authors: Bowers, Robert M., McCubbin, Ian B., Hallar, Anna G., Fierer, Noah
• Format: Article
• Language: English
• Subjects: aerosols; atmospheric chemistry; Bacteria; bacterial communities; cold zones; Colorado Rocky Mountains; Community; community structure; High altitude site; Primary biological aerosol; seasonal variation; sequence analysis; snow; soil; spring; Storm Peak Laboratory; summer; winter
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2012.01.005

Although bacteria are ubiquitous in the near-surface atmosphere, the temporal dynamics of airborne bacterial communities have not been well-studied. We examined seasonal shifts in bacterial abundances, the relative contribution of bacteria to total aerosol loads, and bacterial community structure at a high-elevation research station in northern Colorado, USA. Aerosol samples were collected from the near-surface atmosphere over 5–10 days during each of the four calendar seasons. Bacterial abundances varied by season with the highest concentrations observed during the fall and spring seasons, consistent with the changes in total particle concentrations, with bacterial cells often representing a large fraction (22% on average) of the total near-surface aerosol particles >0.5 μm. Bacterial community composition, determined via barcoded pyrosequencing, also varied significantly by season. The dominant taxa in the spring, winter, and second half of the fall sampling periods (when the ground was snow covered) were bacterial taxa commonly found in other cold environments while the summer and first half of the fall samples contained taxa that were likely derived from soil and leaf-surface environments. Bacteria are clearly an important component of atmospheric aerosols with the abundance and composition of these airborne bacterial communities shaped by seasonal shifts in atmospheric conditions and the conditions of the local terrestrial environment. ► Total particle and bacterial concentrations vary by season. ► Bacteria represent a large proportion of the near-surface atmospheric aerosol >0.5 μm. ► Bacterial community composition changed significantly across the four seasons. ► Seasonal shifts in airborne bacterial communities linked to shifts in bacterial source environments.