Table 3.
Effects of drought on the sizes of soil carbon and microbial marker lipid pools for the peak drought and the recovery labeling campaigns.
| Labeling | Parameter | C content (μgC gdm-1) | ||
|---|---|---|---|---|
|
|
||||
| Control | Drought | D a | ||
| Peak drought | EOC | 34 ± 4 | 102 ± 8 | ∗∗∗ |
| MBC | 402 ± 33 | 429 ± 20 | n.s. | |
| AM fungi | 24 ± 3 | 17 ± 2 | ∗ | |
| Saprotrophic fungi | 1.1 ± 0.1 | 1.2 ± 0.2 | n.s. | |
| Gram (-) bacteria | 5.7 ± 0.4 | 7.1 ± 0.3 | ∗∗ | |
| Gram (+) bacteria | 4.1 ± 0.3 | 4.8 ± 0.2 | ∗ | |
| Actinobacteria | 2.4 ± 0.2 | 2.9 ± 0.1 | ∗ | |
| Recovery | EOC | 32 ± 3 | 32 ± 1 | n.s. |
| MBC | 393 ± 18 | 393 ± 15 | n.s. | |
| AM fungi | 34 ± 2 | 19 ± 2 | ∗∗∗ | |
| Saprotrophic fungi | 0.9 ± 0.1 | 0.9 ± 0.1 | n.s. | |
| Gram (-) bacteria | 6.0 ± 0.4 | 6.6 ± 0.4 | n.s. | |
| Gram (+) bacteria | 4.3 ± 0.3 | 4.6 ± 0.4 | n.s. | |
| Actinobacteria | 2.8 ± 0.2 | 2.9 ± 0.2 | n.s. | |
aLevels of significance for drought effects: ∗∗∗Paovp < 0.001, ∗∗Paovp < 0.01, ∗Paovp < 0.05, (∗)Paovp < 0.1; n.s., not significant. AM, arbuscular mycorrhizal; EOC, extractable organic carbon; MBC microbial biomass carbon. Values represent averages among the mesocosms for each treatment (mean ± SE, n = 6), after averaging over the sampling times (four for EOC and MBC, two for microbial marker lipids) for each mesocosm.