POTENTIAL RATES OF METHANOGENESIS IN SAWGRASS MARSHES WITH PEAT AND MARL SOILS IN THE EVERGLADES

Comparisons of methanogenesis in two sawgrass wetlands of the Florida Everglades revealed that marl soils had a much greater potential rate of methanogenesis than peat soils. In these wetlands methanogenesis (1) decreased rapidly with increased soil depth, (2) increased at higher temperatures, (3) increased with lower Eh, (4) was stimulated by organic compounds (cellulose, glucose and acetate), and (5) remained unaffected by ammonium and phosphate. Lowering the Eh in peat and marl soils with sulfide or sulfate stimulated methanogenesis. Methanogenesis potentials decreased to undetectable values when water levels dropped below the surface, and peaked 1 month after heavy rainfall in November 1989.