Modeling of soil nitrification responses to temperature reveals thermodynamic differences between ammonia-oxidizing activity of archaea and bacteria

Soil nitrification potential (NP) activities of ammonia-oxidizing archaea and bacteria (AOA and AOB, respectively) were evaluated across a temperature gradient (4–42 °C) imposed upon eight soils from four different sites in Oregon and modeled with both the macromolecular rate theory and the square root growth models to quantify the thermodynamic responses. There were significant differences in response by the dominant AOA and AOB contributing to the NPs. The optimal temperatures ( T opt ) for AOA- and AOB-supported NPs were significantly different ( P 12 °C greater than AOB. The change in heat capacity associated with the temperature dependence of nitrification (Δ C P ‡ ) was correlated with T opt across the eight soils, and the Δ C P ‡ of AOB activity was significantly more negative than that of AOA activity ( P