TABLE 2.

Numbers of translated nifH sequences and OTUs, diversity, and coverage at different amino acid sequence similarity levels in ambient and elevated CO₂ plots across sites^a

OTU similarity (%)	Site	No. of sequences		No. of OTUs		1/D		Coverage
		Amb	Elv	Amb	Elv	Amb	Elv	Amb	Elv
99	MDE	383	408	170	185	40.9	53.9	0.71	0.71
	NCD	121	121	53	64	20.0	35.5b	0.79	0.65
	TNO	116	171	60	66	41.1	20.5	0.69	0.78
	WIR	133	159	36	40	5.33	5.46	0.83	0.88
95	MDE	383	408	95	102	22.8	27.5	0.87	0.88
	NCD	121	121	17	29	6.02	4.92	0.96	0.84
	TNO	116	171	18	27	6.78	4.23	0.95	0.92
	WIR	133	159	19	19	4.57	4.05	0.95	0.97
90	MDE	383	408	47	48	6.12	9.29	0.94	0.96
	NCD	121	121	9	14	3.70	2.97	0.98	0.93
	TNO	116	171	11	16	3.38	3.59	0.97	0.96
	WIR	133	159	10	10	3.00	3.10	0.99	0.99

^aAmb, ambient; Elv, elevated. Temperate brackish tidal marsh (MDE), n = 5; warm temperate pine plantation (NCD), n = 3; warm temperate deciduous plantation (TNO), n = 2; cool temperate deciduous plantation (WIR), n = 3. See Materials and Methods for detailed site and soil information.

^bSignificant effect of elevated CO₂ (P < 0.05).