Phosphatase and arylsulphatase activities in wetland soils: annual variation and controlling factors

Phosphatase and arylsulfatase activities were measured in three wetland soils (bog, fen and swamp) in North Wales, UK over 12 months. The fen site (85–176 nmol g−1 min−1) showed the highest phosphatase activity of the three, whilst there was little difference between the arylsulphatase activities of the fen (4–14 nmol g−1 min−1) and the swamp (5–16 nmol g−1 min−1). For both enzymes, the lowest activity was observed in the bog site (20–61 nmol g−1 min−1 for phosphatase; 1–3 nmol g−1 min−1 for arylsulphatase). Hydrogen ion concentration was a dominant controlling factor for the phosphatase activities in all sites. Waterlogging and low temperature seem to restrict enzyme activities in the fen and the swamp sites, as both factors showed significant correlations with the enzyme activities. No temporal relationships between the enzyme activities and the inorganic nutrient concentrations were detected. However, a negative relationship between phosphatase activity and phosphate content was discernable, when compared on a spatial basis.