Table 4. PERMANOVA main tests of bacterial community composition based on Bray-Curtis dissimilarities of OTUs (16S ribosomal amplicon pyrosequencing; ‘no dilution’ and ‘serial dilution’).
| Sources of variation | d.f. | SS | pseudo F | p (perm) 1 | Sq. root |
| Season | 3 | 74205 | 22.705 | 0.001 | 34.644 |
| Dilution | 1 | 71118 | 65.279 | 0.001 | 42.167 |
| pH | 1 | 3637.6 | 3.339 | 0.005 | 8.0436 |
| Season×Dilution | 3 | 62133 | 19.011 | 0.001 | 44.63 |
| Season×pH | 3 | 10129 | 3.0993 | 0.001 | 15.237 |
| Dilution×pH | 1 | 3431.6 | 3.1499 | 0.002 | 10.906 |
| Season×Dilution×pH | 3 | 10272 | 3.1429 | 0.001 | 21.771 |
| Residuals | 63 | 68634 | 33.007 | ||
| Total | 78 | 303900 |
1
Significant results (p (perm)<0.05) are highlighted in bold.
Displayed are tests for the factors ‘season’, ‘dilution’, ‘pH’ and their interactions and the partitioning of multivariate variation for ’no dilution’ and ‘serial dilution’ treatments. p-values were obtained using type III sums of squares and 999 permutations under the full model. d.f.: degrees of freedom, SS: sums of squares, Sq. root: square root of the component of variation attributable to that factor in the model, in units of Bray-Curtis dissimilarities.