Table 1.

Equations for the model with two metabolic functional types—aerobic heterotroph (B_O) and anaerobic heterotroph (B_N)—in a virtual chemostat

$\frac{d{B}_O}{dt}={\underbrace{B_O\left({\mu }_O\right.}}_{\mathrm{biomass}\mathrm{synthesis}}\left.-D\right)$	(T1)
$\frac{d{B}_N}{dt}={\underbrace{B_N\left({\mu }_N\right.}}_{\mathrm{biomass}\mathrm{synthesis}}\left.-D\right)$	(T2)
$\frac{dOM}{dt}={\underbrace{D\left(O{M}_{in}\right.}}_{\mathrm{supply}}\left.-OM\right)-{\underbrace{\frac{1}{y_{O{M}_O}}{\mu }_O{B}_O-\frac{1}{y_{O{M}_N}}{\mu }_N{B}_N}}_{\mathrm{organic}\mathrm{matter}\mathrm{consumption}}$	(T3)
$\frac{d{\mathrm{O}}_2}{dt}={\underbrace{D\left({\mathrm{O}}_{2in}\right.}}_{\mathrm{supply}}\left.-{\mathrm{O}}_2\right)-{\underbrace{\frac{1}{y_{{\mathrm{O}}_2}}{\mu }_O{B}_O}}_{\mathrm{oxygen}\mathrm{consumption}}$	(T4)
$\frac{dN}{dt}={\underbrace{D\left(N_{in}\right.}}_{\mathrm{supply}}\left.-N\right)+{\underbrace{\left(\frac{1}{y_{O{M}_O}}-1\right){\mu }_O{B}_O+\left(\frac{1}{y_{O{M}_N}}-1\right){\mu }_N{B}_N}}_{\mathrm{remineralization}}-{\underbrace{\frac{1}{y_N}{\mu }_N{B}_N}}_{\mathrm{denitrification}}$	(T5)

Growth rates of the two populations (μ_O and μ_N) are calculated with Eq. (1). To correctly estimate the consumption of both limiting and nonlimiting substrates, uptake is written in terms of the growth rate as $V_j=y_j^{-1}\mu$ for substrate j. For organic substrate, (1 − y_j)V_j is partitioned towards respiration (remineralization) rather than biomass synthesis. Biomass B, organic matter OM, and dissolved inorganic nitrogen (N) are resolved in concentrations of nitrogen