Fig. 2: Consumer-resource model describes metabolite dynamics.
From: Functional regimes define soil microbiome response to environmental change
Left column, a consumer-resource model describes the community-level metabolism via a single functional biomass (x), nitrate concentration (A (mM)) and a growth-limiting nutrient concentration (C (mM)). Nitrate consumption rate (\(\mathop{A}\limits^{.}(t)\)) takes a Monod form with a reduction rate parameter (rA (mM per g biomass per day)) and an affinity parameter (KA (mM)). A non-substitutable nutrient (C) is consumed at a rate rC (mM per g biomass per day) with affinity KC (mM). Growth of functional biomass (\(\mathop{x}\limits^{.}(t)\)) is determined by the product of Monod uptake terms for non-substitutable nutrients (A and C) and the growth rate (γ (day−1)). If either nutrient is exhausted, growth halts. The middle and right columns show dynamics of x(t), A(t) and C(t) for two regimes. Chloramphenicol-treated conditions always show constant A and C utilization rates. Middle column, small C(0), large x(0). With low initial C(0) and large x(0), C is rapidly exhausted (at t*), arresting biomass growth (bottom) and resulting in constant A utilization (top). Right column, large C(0), small x(0). Excess C(0) and small x(0) lead to exponential growth in functional biomass, driving exponential depletion of A (black line, top). Growth arrests when A is exhausted. We assume KA ≪ A(0) and KC ≪ C(0) (Methods). Tables define variables and parameters. See Extended Data Fig. 3a–c.
