Table 1.

Microbial cell counts in different samples types and the percent contribution of autofluorescent (AF) cells to the total (DAPI) cells.

Samples	DAPI counts	AF counts	%AF counts
Dust traps	6.1 × 103 ± 1.6 × 103	3.1 × 102 ± 4.2 × 101	5.1 ± 2.6
Snow	5.5 × 102 ± 1.2 × 102	6.1 × 101 ± 1.0 × 101	11.0 ± 8.1
C0	3.8 × 107 ± 9.8 × 106	3.2 × 106 ± 4.2 × 105	8.5 ± 4.3
C1	3.6 × 107 ± 9.6 × 106	2.5 × 106 ± 3.5 × 105	7.0 ± 3.7
C2	3.7 × 107 ± 9.9 × 106	3.8 × 106 ± 3.8 × 105	10.1 ± 3.9
C3	3.9 × 107 ± 1.0 × 107	6.6 × 106 ± 8.8 × 105	17.0 ± 8.5
C4	3.8 × 107 ± 1.0 × 107	5.5 × 106 ± 7.1 × 105	14.3 ± 7.1
C6	4.0 × 107 ± 1.0 × 107	7.1 × 106 ± 8.6 × 105	17.8 ± 8.4
DI0	5.7 × 106 ± 1.2 × 106	9.3 × 105 ± 8.2 × 104	16.3 ± 6.5
DI1	6.2 × 106 ± 1.4 × 106	3.6 × 105 ± 3.4 × 104	5.9 ± 2.4
DI2	6.3 × 106 ± 1.4 × 106	4.1 × 105 ± 3.9 × 104	6.6 ± 2.8
DI3	5.8 × 106 ± 1.2 × 106	1.0 × 106 ± 9.8 × 104	17.9 ± 7.7
DI4	5.9 × 106 ± 1.3 × 106	7.8 × 105 ± 6.9 × 104	13.3 ± 5.2
DI6	6.1 × 106 ± 1.3 × 106	6.1 × 105 ± 6.6 × 104	10.0 ± 4.9

The counts are in cells mL^-1 melted snow for the snow samples and cells g^-1 of debris for the remaining samples. Errors were calculated as 1σ (n = 3).