Carbon sources with the greatest contribution to the
patterns illustrated in Figure 2B were identified by the
Pearson product moment coefficient of correlation (r),
which indicates the strength of the linear relationship
between the carbon source and axis 1 (Table 2). For all
carbon sources listed, r was negative, meaning that
color development, hence microbial activity, was higher
for samples taken from undisturbed sites than it was for
disturbed sites. A list of sites for which the optical
density reading for each of the substrate wells was
greater than 0.5 (which represents the maximum color
change in any of the control wells), revealed greater
microbial activity from undisturbed sites and campsite 7