Figure 2. Color change in meltwater fractions 25 through 30.
Table 5 gives descriptive information, total plate
100 mL, except for the final sample and rinse-water
counts, and fecal streptococcal counts for each melt-
sample where the counts were only slightly higher, 24
CFU/100 mL. There does not appear to be any prefer-
water fraction. Again, the initial samples had signifi-
ential survival of bacteria based upon gram reaction or
cant color and odor while the final samples were rela-
tively clear and had minimal odor. In this case we did
of 24]) of the bacteria in the meltwater were gram posi-
not see the multiple concentration events that were ob-
tive (Table 5) and the remainder were gram negative.
served in the first study, especially with respect to color.
In the previous study, the concentration events were
associated with a period of prolonged warmth that fol-
In this study, the snow column was placed outside,
lowed a significant freezing event. In this study, this
and all the fractions were collected and sampled. Table
occurred on August 4 and we observed that the first
6 gives information on the color and odor of these
samples drawn after this event (on 8/6) had more odor
samples. We see a similar concentration effect in that
than the previous samples.
Total counts were approximately 101 CFU/mL in the
the initial samples had significant color and odor.
initial meltwater and increased to 106 CFU/mL by the
Samples drawn on 7/23 show a slight concentration
event, corresponding with significant warming after a
end of the study when significant warming had oc-
freezing event. The final samples had some sediment
curred. Again, there was a significant increase in the
and thus were a little cloudy but had only a faint musty
number of bacteria in the meltwater when compared
odor. Total counts fluctuated from 101 CFU/mL to 103
with the initial concentration in the snow sample (Table
4). Fecal streptococcal counts were generally <2 CFU/
CFU/mL throughout the experiment and did not in-
Table 4. Summary of total numbers of bacteria in snow and meltwater-
Total number of
of bacteria in
bacteria in last
bacteria in all
volume in column = (mL/bottle)(# bottles collected from column).
number bacteria in snow = (# CFU/mL in snow)(total # mL melted snow in column).
cColony Forming Unit
dNumber bacteria in last meltwater sample = (# CFU/mL in sample)(# mL in sample).
eTotal number bacteria in all the meltwater = Σ #5 for all the fractions.