PNNL

Abstract

Dynamic pH change promoted by biogeochemical reactions in Arctic tundra soils can be a major control on the production and release of CO2 and CH4, which contribute to rising global temperatures. Large quantities of soil organic matter (SOM) in these soils are susceptible to microbial decomposition during permafrost thaw, with pH changes observed during anaerobic decomposition. Soil pH buffering capacity (ß) modulates the extent of pH change, but has not been thoroughly studied in Arctic tundra soils and is not represented in predictive ecosystem scale biogeochemical models. In this study, we generated titration curves for 21 acidic tundra soils from three Arctic sites across northern Alaska, United States. Geochemical and hydrological soil properties were evaluated, and correlations with ß were developed. Strong correlations between ß and both gravimetric water content (?g) (R2 = 0.847, p