Correlations between the phylogenetic distance (weighted UniFrac distance) of airborne bacteria and fungi identified from the 5 sampling events and measured meteorological conditions during each 4-h sampling event (Euclidean distances)a

Meteorological variableCorrelation (Spearman's r value)
Air temp0.29-0.37
Solar irradiance0.08-0.06
Barometric pressure-0.15-0.07
Avg wind speed-0.30-0.47
Peak wind speed-0.30-0.47
Wind direction-0.66-0.59
  • a UniFrac distances between samples are identical to those in Fig. 4, except that we have only included samples collected from Boulder, CO, in the analyses. Combining variables did not significantly improve any of the correlations, so we have only shown correlations between individual meteorological variables and the UniFrac distances. A negative correlation indicates that the samples that were more similar with respect to the measured meteorological variable were less similar with respect to their bacterial or fungal assemblages. The asterisk indicates a significant correlation (P = 0.05, corrected for multiple comparisons).