Vertical stratification of the air microbiome in the lower troposphere.

The troposphere constitutes the final frontier of global ecosystem research due to technical challenges arising from its size, low biomass, and gaseous state. Using a vertical testing array comprising a meteorological tower and a research aircraft, we conducted synchronized measurements of meteorological parameters and airborne biomass (n = 480) in the vertical air column up to 3,500 m. The taxonomic analysis of metagenomic data revealed differing patterns of airborne microbial community composition with respect to time of day and height above ground. The temporal and spatial resolution of our study demonstrated that the diel cycle of airborne microorganisms is a ground-based phenomenon that is entirely absent at heights >1,000 m. In an integrated analysis combining meteorological and biological data, we demonstrate that atmospheric turbulence, identified by potential temperature and high-frequency three-component wind measurements, is the key driver of bioaerosol dynamics in the lower troposphere. Multivariate regression analysis shows that at least 50% of identified airborne microbial taxa (n = ∼10,000) are associated with either ground or height, allowing for an understanding of dispersal patterns of microbial taxa in the vertical air column. Due to the interconnectedness of atmospheric turbulence and temperature, the dynamics of microbial dispersal are likely to be impacted by rising global temperatures, thereby also affecting ecosystems on the planetary surface.

Comparison of Two Measures of Working Memory Impairments in 220 Adolescents and Adults With ADHD.

Objective: This study tests the hypotheses that (a) adolescents and adults with ADHD score lower on two normed measures of verbal working memory, relative to their overall verbal abilities, than the general population and (b) a specific story memory test is a more sensitive and relevant measure of working memory impairment than a numerically based test. Method: Scores on normed story memory and numerical memory tests of 220 adolescents and adults with ADHD were corrected for the individual's verbal abilities and compared with each other and national norms. Results: Participants with ADHD scored significantly below their verbal ability measure on both verbal and numerically based memory tests in comparison with national norms. Scores on verbal memory test were lower than scores for numerically based memory tests. Conclusion: This story memory test is a more sensitive measure of working memory impairments in adolescents and adults with ADHD than measures based on recall of numerical data.