Table 2.

Diversity estimation of the 16S rRNA gene libraries for the R- and S-samples.

Sample	OTU number		Chao 1 index		Shannon index		Simpson index
	R	S	R	S	R	S	R	S
L	2007 ± 275	1492 ± 274	8704 ± 582	6947 ± 1464	7.41 ± 0.78	5.51 ± 1.20	0.96 ± 0.02	0.86 ± 0.08
M	1986 ± 268	1618 ± 246	9759 ± 1750∗	6557 ± 685∗∗	7.34 ± 0.85	5.70 ± 0.90	0.96 ± 0.03	0.86 ± 0.07
H	2089 ± 202	1698 ± 251	8338 ± 407	7234 ± 859	7.85 ± 0.71	6.50 ± 1.03	0.97 ± 0.02	0.91 ± 0.04

R: root samples; S: substrate samples; L: low influent TAN concentration group (0.75 mg/L); M: middle influent TAN concentration group (2.31 mg/L); H: high influent TAN concentration group (7.23 mg/L). Differences among the L, M, and H groups were tested using one-way ANOVA. Different characters indicate significant differences (p < 0.05). Differences between the R- and S-samples of each group were determined using Student's t-test. “∗” and “∗∗” indicate significant differences (p < 0.05) (means ± SD, n = 3).