FIG. 1.

Inverse Gaussian-mixed Poisson and mixture-of-two-geometrics frequency count distributions fitted to 97% OTU data. The inverse Gaussian-mixed Poisson distribution was calculated as follows:

(1)

where j = 0, 1, and so forth, t₁ = 0.3431, and t₂ = 0.7959. The mixture-of-two-geometrics distribution was calculated as follows:

(2)

where j = 0, 1, and so forth, t₁ = 0.3672, t₂ = 7.2341, and t₃ = 0.8220. (A) Frequency count distribution fitted to frequency data. (B) Fitted frequency count distribution extended to zero.