Phosphorus loading effects on extracellular enzyme activity in everglades wetland soils

The impact of P loading to the northern Florida Everglades has been implicated in changing vegetation patterns, pest accretion rates, and other soil physico-chemical properties. This investigation focused on determining the influence of P loading on the activities of various extracellular enzymes along a P-enrichment gradient and relating measured enzyme activities to soil physico-chemical parameters. Alkaline phosphatase activity (APA) was the only enzyme affected by P loading and was negatively related to soil P concentrations and microbial biomass C and P, Arylsulfatase, beta -d-glucosidase, protease, and phenol oxidase were not affected by P loading and were not related to measured soil C, N, S, and P physical and chemical parameters. All enzyme activities were highest in the surface detritus layer and decreased with soil depth. Due to significant relationships between APA and soil and microbial P parameters, APA appears to be a useful indicator for assessing impacts of P enrichment in wetland soils.