exhibited in both samples. This concentration was 8 times lower than another wetland

study that examined phosphatase linearity in order to establish optimum substrate

concentrations (Kang and Freeman, 1999).

P-glucosidase

 The highest MUF-glucoside concentration of 500 pM yielded Tf-Ti activity

differences with average values of 565 and 989 in Fl and U3 samples respectively, with

laboratory replicate standard errors of 1.8% and 9.3% of the mean (Figures 2-3a & 2-3b).

Quasi-linear graphs were produced with the highest activity values occurring at the U3

site. 5 pM average activity values were 267 and 88 with standard errors representing

7.6% and 50.8% of the mean for the Fl and U3 sites, respectively. The relationship of

enzyme activity between sites shifted from the general trend at approximately 200 [tM

and continued until approximately 300 [tM (Figure 2-3c). This illustrates the profound

effect that substrate concentrations can have on formulating conclusions.

 The most consistent substrate concentration in terms of net activity, linearity and

error was identified at 100 aM. These runs yielded mean activities of 416 and 248 with

standard errors of 8.1% and 4.8% of the mean for the Fl and U3 sites, respectively.

 There was a linear response of enzyme activity over time with no apparent effect of

increasing incubation time on mean activities or differences among the sites.

Leucine Aminopeptidase

 Leucine aminopeptidase exhibited typical activity responses to increasing substrate

concentrations (Figure 2-4c). Peak activity was around 800 [aM and decreased in

response to a higher or lower concentration. As substrate concentration was decreased

from 800 [aM, the differences between the two sites and the replicate errors also