2.4.Calculation of metabolic functional diversity indices
Average well-color development (AWCD) was calculated by averaging the final absorbance values for all substrate wells, as described by Garland (Jay L. Garland, 1997):
AWCD = ∑(Ci-R)/31,
where Ci is the absorbance value of each reaction well at different incubation times at 590 nm, excluding the control well, and R is the absorbance value of the control well. The Shannon index (H) was calculated as follows:
H = -∑(Pi × lnPi), Pi = (Ci-R)/∑(Ci-R),
where pi is the proportion of the corrected absorbance value of each well to the sum of absorbance values of all wells and n is the total number of carbon sources (Jay L. Garland, 1997). The Simpson diversity index (D) was determined via the following equations:
D = 1-∑Pi2.
McIntosh diversity (U):
U =, ni = Ci-R.