TABLE 1.
Potential CH4 and NH4+ oxidation rates and the contribution of methanotrophs to nitrification in soil slurries from the root and nonroot compartments of rice microcosms
| Compartment | CH4 oxidationa (μmol of CH4 · g [dry wt]−1 · h−1) | NH4+ oxidation (nmol of NO3− + NO2− · g [dry wt]−1 · h−1)
|
Contribution of methanotrophs to NH4+ oxidation (% of total activity)
|
|||
|---|---|---|---|---|---|---|
| Without CH4 | With CH4 | With CH4 + CH3F | Without CH4b | With CH4c | ||
| Root | 1.43 ± 0.09*d | 2.99 ± 1.66 | 9.95 ± 0.32* | 1.51 ± 0.82 | 55.74 ± 14.32 | 84.97 ± 7.72 |
| Nonroot | 0.66 ± 0.30 | 2.13 ± 0.58 | 3.09 ± 1.09 | 1.05 ± 0.79 | 44.48 ± 25.90 | 61.69 ± 35.55 |
a
Without NH4+.
b
Calculated as [1 − (NH4 oxidation with CH4 plus CH3F/NH4 oxidation without CH4 or CH3F)] × 100.
c
Calculated as [1 − (NH4 oxidation with CH4 plus CH3F/NH4 oxidation with CH4 alone)] × 100.
d
Asterisks indicate significant differences between root and nonroot compartments (t test; P > 0.05; n = 4).