TABLE 2.

Observed and estimated total OUs for phenanthrene-contaminated samples^a

Library	nb	No. of OUs	Rarefaction analysisc						Chao1d
			R1		R2		R3
			a1	r12	a2	r22	a3	r32
T63LP	37	4	4.01 + 0.22	0.941	4.63 + 0.19	0.977	5.16 + 0.21	0.963	4
T63CP	85	23	23.22 + 0.16	0.991	27.72 + 0.37	0.999	30.96 + 0.16	0.998	30.2

^aRarefaction analysis and the nonparametric richness estimator Chao1 were used for diversity estimation.

^bn, number of clones in the clone library.

^ca, asymptote of the regression equation giving the estimated total diversity; r, correlation coefficient.

^dChao1, estimated total diversity.