Fig. 2.

16S rRNA gene copy number of bacteria and archaea in each density fraction of gradients obtained by isopycnic centrifugation of soil DNA from different treatments. Relative values were calculated considering the total number of copies in each gradient. Each panel depicts controls and treatments (H₂¹⁸O, H₂¹⁸O DCMU incubated in the light or in the dark). Significant differences (p < 0.05, Student’s t-test) between controls and treatments are indicated by an (*). Bars indicate standard deviation of triplicates