TABLE 3.

Calculation of cell-cell distance

Day	Total no. of cellsa/ml	Mean cell-cell distanceb (μm)	Maximum avg interspecies distance for H2 transferc (μm)
2	6.2 × 106	55.3	14
4	5.0 × 107	27.1d	6.3d
6	9.2 × 107	22.2	2.7
8	13.7 × 107	19.6	1.9

^aThat is, for strain 195 plus S. wolfei.

^bThe cell-cell distance was based on one sample and was calculated for suspended cells using the cell number quantified from quantitative PCR analysis.

^cThat is, for the transfer of S. wolfei to strain 195 at the observed substrate oxidation rate. Values were calculated using Fick's diffusion law.

^dDetailed calculations for these values can be found in the supplemental material, part 4.