Table 1.

Numbers of amplified sequences, OTUs and assigned genera for the different denitrification genes.

Gene	Total sequence numbers before noise removal	Total sequence numbers after noise removal	OTU threshold (%)	No. of OTUs	No. of assigned genera
napA	19140	12358	93	436	34
narG	13684	6786	96	1025	70
nirS	13286	2389	95	369	30
nirK	7665	4178	95	642	23
qnorB	10508	4683	83	465	31
nosZ	11213	4439	89	164	26

The OTU thresholds were defined based on the taxonomic assignment, for detailed information see Supplementary Figures S1–S6.