TABLE 1.

Descriptive statistics for the observational study in the Upper Arkansas River^a

Location	Season	n	pH		Sediment Cd		Sediment Cu		Sediment Zn		Observed OTUs		Shannon index
			Mean	StdDev	Mean	StdDev	Mean	StdDev	Mean	StdDev	Mean	StdDev	Mean	StdDev
Upstream	Spring	8	7.63 a*	0.21	1.59 a	0.41	4.29 a	1.15	220.24 a	92.16	4825 a	1132	6.56 a	0.35
CalGulch	Spring	4	7.12 b*	-	23.66 b	10.15	331.30 b	113.47	6300.8 b	1673.60	2414 b	1403	5.84 b	0.25
Downstream	Spring	13	7.41 c*	0.05	6.29 c	4.09	53.56 c*	69.58	1145.10 c*	590.00	4095 a*	1149	6.49 a	0.33
Upstream	Fall	8	7.75 A**	0.53	1.74 A	0.58	4.19 A	2.28	167.17 A	111.22	5288 A	1011	6.70 A	0.23
CalGulch	Fall	4	7.50 B**	-	33.45 B	16.58	382.49 B	174.56	6488.64 B	1059.45	2729 B	389	5.65 B	0.06
Downstream	Fall	14	7.49 B**	0.07	5.14 C	2.81	18.13 C**	8.24	767.12 C**	395.35	5033 A**	827	6.49 A	0.41

^aDifferent letters refer to a statistically significant difference (α = 0.05) among locations (upstream, California Gulch [CalGulch], and downstream samples) in the spring (lowercase) and in the fall (uppercase). Asterisks refer to a statistically significant difference (α = 0.05) between spring and fall for each location. OTU, operational taxonomic unit; -, not applicable (sample size of 1).