highly significantP =6.42 x 10 −7
Regression analyses of the log-transformed ratio of archaeal to bacterial 16S rRNA gene copies indicated a highly significant and inverse relationship with pH ( β =−0.22, adjusted R 2 =0.29, P =6.42 x 10 −7 ; Supplementary Figure S1 ) but no significant correlation with temperature ( β =0.00, adjusted R 2 =−0.01, P =0.83).