Table 2.

Counts of methanogenic populations in anoxic soil of different flooded rice paddy soil microcosms determined by the MPN dilution method

SubstrateIncubation time (wk)Cell count (per g of dry soil)95% Confidence interval
H2-CO264a4.6 × 1069.9 × 105–1.3 × 107
572.0 × 1064.6 × 105–6.1 × 106
132.3 × 1074.4 × 106–8.3 × 107
Formate64a2.7 × 1065.2 × 105–9.9 × 106
132.9 × 1055.6 × 104–1.1 × 106
Acetate64a6.1 × 1051.7 × 105–1.7 × 106
571.3 × 1062.5 × 105–4.6 × 106
555.1 × 1051.4 × 105–1.4 × 106
Methanol64a2.2 × 1054.7 × 104–9.9 × 105
137.5 × 1051.3 × 105–3.7 × 106
  • a Total community DNA extracted from the same soil sample was used to generate the clone library analyzed in this study (see the text).