Table 5. Absolute and relative quantification of 16S rRNA, nirK and nirS genes in both estuarine sediment types (HBM and LBM).

Sample	Absolute quantification			Relative quantification
	16S rRNA a gene	nirK b gene	nirS c gene	ratio	ratio
	copies / g sediment	copies / g sediment	copies / g sediment	nirK/16S rRNA	nirS/16S rRNA
HBM1	(6.68 ± 0.85) x 107	(3.39 ± 0.38) x 104	(2.93 ± 0.16) x 105	0.0005	0.0044
HBM2	(3.75 ± 0.13) x 107	(5.40 ± 0.72) x 104	(2.53 ± 0.18) x 105	0.0014	0.0068
HBM3	(7.98 ± 0.48) x 107	(6.09 ± 0.70) x 104	(3.35 ± 0.26) x 105	0.0008	0.0042
LBM1	(5.56 ± 0.64) x 106	(1.48 ± 0.15) x 103	(3.66 ± 0.60) x 104	0.0003	0.0066
LBM2	(5.19 ± 0.40) x 106	(8.61 ± 0.36) x 103	(6.00 ± 0.55) x 104	0.0017	0.0116
LBM3	(8.25 ± 0.24) x 105	(2.72 ± 0.37) x 103	(6.23 ± 0.14) x 104	0.0033	0.0755

Analyses was performed in triplicate for each biological replicate (n = 3). Gene copy numbers given were corrected for PCR inhibition.

a. Detection limit, 10¹ copies; PCR efficiency, 90.4%; standard curve R², 0.99; inhibition factor range: 0.07–0.10.

b. Detection limit, 10¹ copies; PCR efficiency, 87%; standard curve R², 0.99; inhibition factor range: 0.36–0.62.

c. Detection limit, 10¹ copies; PCR efficiency, 62.9%; standard curve R², 0.99; inhibition factor range: 0.31–0.55.