Table 2.

Results of AMOVA

Sequence subset	Grouping parameter	% variation			Variation among groups
		Among groups	Among clone libraries within groups	Within clone libraries	No. of degrees of freedom	P valuea
All sequences	Region	8.44	25.16	66.40	7	0.017 ± 0.001
	Temp	2.67	29.89	67.44	2	0.102 ± 0.003
	Sample type (F)b	6.28	28.09	65.63	4	0.046 ± 0.002
	Sample type (F&P)c	15.81	21.76	62.44	4	0.000 ± 0.000
Microbial mat samples only	Region	8.31	19.85	71.84	2	0.028 ± 0.001
	Temp	4.71	23.35	71.94	2	0.124 ± 0.003
OTU 1	Region	12.63	82.94	4.43	2	0.118 ± 0.003
	Temp	−11.98	106.87	5.11	1	0.939 ± 0.003
OTU 2	Region	29.96	30.52	39.52	2	0.107 ± 0.003
	Temp	2.41	45.00	52.59	2	0.232 ± 0.004
Subset with known [Fe]	Region	3.33	21.30	75.37	2	0.245 ± 0.004
	Temp	4.20	19.61	76.19	2	0.161 ± 0.004
	Total Fe (μM)	−3.47	25.54	77.93	3	0.371 ± 0.005

^aSignificant P values (α = 0.05) are highlighted in boldface.

^bF, full-length data set only.

^cF&P, full- plus partial-length data set.