Figure 1.

Cumulative CO₂ (mean±s.e.) from ¹³C uniformly labeled glucose respired during 10 days in control and NaN₃-treated soils (top left), +NaN₃:Control ¹³C (mean±s.e.) respiration rate ratio from individual glucose position (top right) and cumulative ¹³C (mean±s.e.) recovered in CO₂ released from position-specific ¹³C-labeled glucose applied to soil with control (bottom left) and azide-exposed (bottom right). ¹³C curves were fitted with nonlinear least-square regressions according to an exponential equation (cum¹³C(t)=¹³C_max*(1−e^−kt)), where cum ¹³C (t) is the cumulative ¹³C amount depending on time, ¹³C_max is the parametrically determined maximum of ¹³C, k is the mineralization rate and t is time (parameter estimates in Supplementary Table S4). Steven' runs test for the fitted ¹³C curves revealed no deviation from linearity (Supplementary Table S5). Significant differences between fitted curves are displayed in Supplementary Table S6.