highly significantp < 0.001
Mantel correlation further indicated that while the bacterial community structure of the FL and PA size fractions were significantly different (ANOSIM test: R = 0.37, p < 0.001; Supplementary Table S9 ), there was a highly significant positive relationship between the two size fractions ( r = 0.92, p < 0.001; Partial mantel test) ( Figure 8 ).