Table 2. Relative abundances of bacteria phyla (classes) on day 0 and when 20% of PAH contamination had disappeared, i.e. days 91 and 189 in sand and other soils (both pristine and contaminated), respectively.

	Week 0		No creosote		Creosote added
Phylum	Mean	1SD	Mean	1SD	Mean	1SD
Acidobacteria	0.240	0.110	0.269	0.089	0.268	0.170
Actinobacteria	0.150	0.060	0.092*	0.041	0.049*	0.016
Armatimonadetes	0.001	0.001	0.002	0.002	0.000	0.000
Bacteroidetes	0.048	0.026	0.069*	0.034	0.010*	0.013
Candidate_division_WPS-1	0.000	0.000	0.001	0.002	0.000	0.000
Candidatus_Saccharibacteria	0.014	0.010	0.013*	0.006	0.002*	0.003
Chlamydiae	0.001	0.001	0.004	0.007	0.001	0.002
Chloroflexi	0.002	0.003	0.002	0.004	0.001	0.001
Fibrobacteres	0.001	0.003	0.002	0.003	0.000	0.000
Firmicutes	0.008	0.010	0.015	0.015	0.031	0.062
Gemmatimonadetes	0.030	0.060	0.007	0.013	0.001	0.003
Nitrospirae	0.001	0.004	0.002	0.003	0.001	0.002
Parcubacteria	0.001	0.001	0.003*	0.003	0.001*	0.000
Planctomycetes	0.004	0.005	0.005	0.005	0.004	0.006
Proteobacteria	0.358	0.077	0.315*	0.071	0.509*	0.166
Alphaproteobacteria	0.100	0.026	0.120	0.033	0.127	0.075
Betaproteobacteria	0.165	0.035	0.082*	0.032	0.234*	0.057
Gammaproteobacteria	0.043	0.021	0.054	0.019	0.076	0.018
Deltaproteobacteria	0.047	0.015	0.057	0.041	0.061	0.022
Unclassified proteobacteria	0.004	0.002	0.003	0.001	0.010	0.003
Spirochaetes	0.003	0.008	0.009	0.022	0.000	0.001
Unclassified bacteria	0.081	0.070	0.130	0.107	0.049	0.061
Verrucomicrobia	0.040	0.030	0.060	0.035	0.074	0.054

To compare contaminated and pristine treatments, we conducted t-test between creosote added and no creosote.

Significant differences indicated by asterisk (p<0.05).

P-values corrected by FDR.