Table 1.
Statistical results from the mixed effects models of the variables measured per sediment layer.
| Factors |
|||||
|---|---|---|---|---|---|
| RM | DPD × RM | ||||
| Variable | Sediment layer | F(2,18) | p | F(4,18) | p |
| WC (%) | Surface | 5.38 | 0.018 | 0.45 | ns |
| Deep | 7.64 | 0.0005 | 0.13 | ns | |
| Sediment NO3− (μg N g−1 DM) | Surface Deep |
1.23 2.28 |
ns ns |
0.36 11.62 |
ns 0.0002 |
| Sediment NH4+ (μg N g−1 DM) | Surface Deep |
4.75 4.03 |
0.022 0.035 |
2.90 0.97 |
0.05 ns |
| Sediment DON (mg N g−1 DM) | Surface Deep |
1.22 2.17 |
ns ns |
2.06 0.65 |
ns ns |
| AO rates (μg NH4+-N g−1 DM h−1) | Surface Deep |
0.48 39.56 |
ns <0.0001 |
0.67 10.24 |
ns 0.0003 |
| DNA (ng DNA g−1 DM) | Surface Deep |
2.20 0.07 |
ns ns |
0.45 0.32 |
ns ns |
| AOA (RA) | Surface Deep |
3.72 1.51 |
0.004 ns |
0.37 0.89 |
ns ns |
| Marine AOA (RA) | Surface Deep |
0.45 0.61 |
ns ns |
0.48 |
ns ns |
| Soil AOA (RA) | Surface Deep |
0.98 20.88 |
ns <0.0001 |
0.66 3.35 |
ns 0.038 |
| AOB (RA) | Surface Deep |
0.68 13.97 |
ns <0.001 |
0.91 2.40 |
ns ns |
| amoA AOA (n° copies g−1 DM) | Surface Deep |
0.54 3.61 |
ns 0.048 |
2.38 9.48 |
ns 0.0003 |
| amoA AOB (n° copies g−1 DM) | Surface Deep |
13.53 |
0.0003 0.05 |
2.33 1.08 |
ns ns |
Models included the factors: dry period duration (DPD = 3, 6, and 9 weeks), rainfall magnitude (RM: 0, 4, and 21 mm) and interaction of both factors. Results from the effects of the RM and from the interaction RM × DPD are only shown. ns indicates results no significant at P-value > 0.05. WC: water content, AO: ammonia oxidation; AOA: ammonia-oxidizing archaea; AOB: ammonia-oxidizing bacteria; DM: dry mass. RA: relative abundance. Marine AOA refers to the order Nitrosopumilales while Soil AOA refers to the order Nitrososphaerales.