TABLE 1.

Phylum level composition of 16S rRNA gene libraries from uranium-contaminated sites in the United States^a

Parameter	Site
	Tennessee							Colorado
	Background area		Area 1		Area 2			Up-gradient		Down-gradient
	FB300	FB605	TPB10	FW015	TPB15g	TPB16	DP13	G07	G16	P02	P03
% of clones of bacterial phylum
Proteobacteria	15.0	38.7	14.0	3.5	6.9	11.1	11.9	24.6	29.4	32.1	39.7
Chloroflexi	2.7	1.3	20.2	20.2	5.1	4.7	14.3	18.0	17.6	12.5	14.7
Actinobacteria	11.0	6.7	10.1	16.7	3.5	7.9	2.4	6.6	17.6	10.7	10.3
Acidobacteria	17.8	20.0	9.0	15.5	1.7	3.2	7.1	0	11.8	7.1	2.9
Firmicutes	4.1	2.6	5.1	1.2	0	52.4	0	3.3	2.0	14.3	8.8
Chlorobium	0	2.6	3.8	2.6	69.0	0	4.8	8.2	2.0	1.8	7.4
Verrucomicrobia	5.5	4.0	1.2	0	3.5	0	14.3	13.1	5.9	0	1.5
Gemmatimonadetes	2.7	0	6.3	7.1	1.7	0	0	0	0	3.6	1.5
Incertae sedisb	5.5	4.0	3.8	0	6.9	1.6	0	6.6	3.9	3.6	1.5
Other	12.3	9.3	6.3	6.3	0	3.2	0	4.9	5.9	8.9	2.9
Unclassifiedc	23.3	14.6	20.2	26.2	1.7	15.9	45.2	14.7	3.9	5.4	8.8
Total no. of clones	73	75	79	84	58	63	42	61	51	56	68
Total no. of sequence typesd	73	75	78	73	29	61	42	61	51	56	68
Phylum richnesse	12	11	10	9	8	7	6	10	7	12	11
Library coveragef	1	1	1	1	2	1	1	1	1	1	1

^aCells containing >10% of sequences for that library are in boldface type.

^bGenera insertae sedis includes members of the candidate phyla TM7, WS3, OP10, and OP11.

^cUnclassified sequences could not be placed into any known phylum with high confidence.

^dTotal number of sequence types determined using the FastGroup program as described in the supplemental material.

^ePhylum richness is the number of divisions identified in the clone library not including sequences in the “unclassified” category.

^fLibrary coverage is the number of clones divided by the number of sequence types.

^gThis sample is located downstream of a reactive barrier for U removal from groundwater.