Figure 4. Variables influencing enzyme activities and iron-bound lignin phenols in the alpine wetland soils.

(a) Correlations of phenol oxidative and β-glucosidase activities with ferrous iron [Fe(II)] content; (b) correlations of soil pH and specific ultraviolet absorbance at 254 nm (SUVA₂₅₄) in the water-extractable organic matter with phenol oxidative activity; and (c) correlation between SUVA₂₅₄ and iron-bound lignin phenol content. Solid lines indicate significant linear correlations across the entire soil profile (n=32 in a, b and n=24 in c).