FIG. 1.

VFA-induced methane formation in microcosms with soil from F1 (eutrophic), F4 (transition), and U3 (oligotrophic) regions of the Florida Everglades. Propionate (A) and butyrate (B) results are shown. 12C labels indicate the addition of unlabeled carbon donor; 13C labels indicate the labeled isotope. Analyses were conducted in duplicate, and mean values are presented; error bars represent ±1 standard deviation. A second addition of [¹³C]butyrate or [¹³C]propionate was performed at 4 weeks.