increased with depth, ranging from 13% to 27% and was generally higher at the reference

sites, with the exception of ENP-TS.

 Compared to the benthic layer, hydrolytic enzyme activities in the soil layer had

fewer significant differences along the P gradient (Tables 4-4 & 4-5). Average soil layer

BGL activity was consistently lower than the benthic activity. Soil BGL ranged from

0.05 to 0.39 .moles g-1 AFDM h-1 and decreased from the ENR to REF site in all areas

with significant differences in 2 of 3 sampling periods in WCA-3A and ENP-TS. The

largest contrast between the ENR and REF sites occurred in ENP-TS. Soil BGL was

negatively correlated with Mg.

 Soil leucine aminopeptidase (LEU) activity was lower in 10 of 12 sites in

comparison to the benthic layer and ranged from 1.92 to 3.58 [moles g-1 AFDM h-1.

LEU was generally not significantly different between the enriched and reference sites.

LEU was negatively correlated with TN, TOC, and lignin. There was not a consistent

relationship between LEU activity and the P gradient. Soil PHO also did not

significantly vary between the REF and ENR sites. Values were consistently lower in the

soil layer, reflecting activities as great as 10 times lower those in the corresponding

benthic layer. This depth relationship has been previously documented in other areas

(Newman and Reddy, 1993; Wright and Reddy, 2001b). Soil PHO was negatively

correlated with TP, TN, TOC, lignin, and positively correlated with Ca (Table 4-6). Soil

PHE and PER activities increased with depth. PHE was weakly negatively correlated

with TN, TOC, and lignin, while PER was not correlated with any parameters. The

increase of oxidative activity with depth is in disagreement with earlier studies within the