Table 2. Contribution of functional genes implicated in the N cycle to compositional dissimilarity as determined by SIMPER.

Process	Gene	Average Dissimilarity	Percent Contribution	Cumulative Percent Contribution
Denitrification			67.2	67.2
	napA	1.8	24.9
	narG	1.4	19.1
	norB	1.1	15.3
	nosZ	0.3	3.8
	nirK	0.2	2.7
	nirS	0.1	1.4
Assimilatory NO3 reduction			21.5	88.7
	nirB	0.9	12.0
	nirA	0.7	9.5
Nitrification			6.6	95.3
	nxrB	0.3	4.4
	ureA	0.2	2.2
N Fixation			4.8	100
	nifD	0.2	2.8
	nifH	0.2	2.0