Fig. 2. Microbial degradation of organic acids as measured by microbially respired ¹⁴CO₂ in a high pH calcareous Typic Rendoll and low pH Typic Fragiochrept soil. (A) Low (0.005 µmol g^-1) and (B) high (5 µmol g^-1) organic acid addition to the soil. Clear bars represent the amount of ¹⁴CO₂ recovered in a static NaOH-trap (Step 1), while striped bars represent the amount of ¹⁴CO₂ recovered after the addition of HCl to the soil (Step 2; see Materials and Methods for details). Values represent means ± standard error of the mean, n = 3 (n.d. indicates not detectable)