CARBON, NITROGEN, AND PHOSPHORUS MINERALIZATION IN NORTHERN WETLANDS

Abstract

We examined rates of C, N, and P mineralization in soils from 16 northern Minnesota wetlands that occur across an ombrotrophic–minerotrophic gradient. Soils were incubated at 30°C under aerobic and anaerobic conditions for 59 wk, and the results were fit with a two-pool kinetic model. Additionally, 39 different soil quality variables were used in a principal components analysis (PCA) to predict mineralization rates. Mineralization of C, N, and P differed significantly among wetland types, aeration status (aerobic vs. anaerobic), and their interaction term. Despite low total soil N and P, there was a rapid turnover of the nutrient pools in ombrotrophic sites, particularly under aerobic conditions. On a volumetric basis, C and N mineralization increased in a predictable manner across the ombrotrophic–minerotrophic gradient, largely due to increasing soil bulk density. However, P mineralization per cubic centimeter remained relatively high in the bogs. The higher total P content of more minerotrophic soils a...