TABLE 2.

Average fractionation into biomass for different organismic groups and substrates^a

Organismic group	Substrate	Δsubstrate-biomass (avg ± SD)	No. of replicates
Acetogens	CO2	−12.9 ± 5.0	18
Methanogens	CO2	−18.5 ± 6.3	23
Sulfate reducers	CO2	−20.4 ± 13.9	5
Phototrophs	CO2	−23.0 ± 8.4	8
Methanogens	Methanol	−20.5 ± 11.9	5
Methanogens	Acetate	+1.4 ± 6.7	4
Sulfate reducers	Acetate	−6.5 ± 1.3	2
Fermenting bacteria	Glucose	−0.4 ± 1.9	6
Acetogens	Glucose	−3.3 ± 3.0	6

^aDetails can be found in Table S1 in the supplemental material.