Table 3. Nutrient effect on carbon and nitrogen content (% DW) and on the CN ratio.
Split-plot ANOVA with the fixed factor ‘Nutrient’ and the random factors ‘Mesocosm’ and ‘Sibling group’. Effects of the nutrient treatment were analysed for (A) the carbon content (% DW), (B) the nitrogen content (% DW) and (C) the CN ratio. Df: degrees of freedom, SS: sums of squares and MS: mean squares. ‘Den. Syn. Error df’ and ‘Den. Syn. Error MS’ describe the denominator synthesis of degrees of freedom and mean squares, respectively.
| Source of variation | df | SS | MS | Den. Syn. Error df | Den. Syn. Error MS | F-value | p-value |
|---|---|---|---|---|---|---|---|
| (A) Carbon content | |||||||
| Nutrients | 1 | 36.563 | 36.563 | 1.998 | 17.839 | 2.05 | 0.289 |
| Mesocosm (Nutrients) | 4 | 79.878 | 19.969 | 16 | 15.482 | 1.290 | 0.315 |
| Sibling | 4 | 145.584 | 36.396 | 4 | 13.352 | 2.726 | 0.177 |
| Sibling x Nutrients | 4 | 53.407 | 13.352 | 16 | 15.482 | 0.862 | 0.507 |
| Error | 16 | 247.718 | 15.482 | ||||
| (B) Nitrogen content | |||||||
| Nutrients | 1 | 6.676 | 6.676 | 3.669 | 38.545 | 0.173 | 0.700 |
| Mesocosm (Nutrients) | 4 | 159.792 | 39.948 | 16 | 5.462 | 7.314 | 0.002 |
| Sibling | 4 | 16.647 | 4.162 | 4 | 4.059 | 1.025 | 0.491 |
| Sibling x Nutrients | 4 | 16.235 | 4.059 | 16 | 5.462 | 0.743 | 0.576 |
| Error | 16 | 87.387 | 5.462 | ||||
| (C) CN ratio | |||||||
| Nutrients | 1 | < 0.001 | < 0.001 | 4.488 | 333.810 | < 0.001 | 1 |
| Mesocosm (Nutrients) | 4 | 1226.652 | 306.663 | 16 | 42.265 | 7.256 | 0.002 |
| Sibling | 4 | 297.260 | 74.315 | 4 | 69.412 | 1.071 | 0.474 |
| Sibling x Nutrients | 4 | 277.649 | 69.412 | 16 | 42.265 | 1.642 | 0.212 |
| Error | 16 | 676.237 | 42.265 | ||||