Fig. 3.

Model simulations. (A) Comparison of eCO₂-induced percent changes of hydrolytic and oxidative enzymes observed by GeoChip to the simulated effects by gMEND and traditional MEND without gene information (tMEND) at low N supply. The GeoChip data were obtained from the samples from 2009. (B) Parameter uncertainty quantified by the coefficient of variation (CV) for the nonmicrobial C-only TECO, tMEND, and gMEND models; the bars show mean CV of 10 calibrated parameters represented by dots. (C) Model calibration with the soil respiration (R_s, 1998 to 2009) at aCO₂-aN. (D) Model validations were performed using R_s at eCO₂-aN, aCO₂-eN, and eCO₂-eN for gMEND and TECO. (E) Percent changes of gMEND-simulated heterotrophic respiration (R_h) between different CO₂ and N levels. The error bars represent SEs. P values of the permutation t test are labeled as **P < 0.01.