Figure Captions
Figure 1. Effect of temperature and enzyme allocation fraction on SOC ecosystem equilibrium. a , Structure of the microbial-enzyme ecosystem model (see Methods for details): SOC stock is the balance of plant input, I , and loss by exoenzyme-mediated degradation to DOC (D ), which in turn is allocated between (fraction φ ) production of exoenzymes (Z ) and (fraction 1−φ ) growth of microbial biomass (M ). b , Effect of temperature and exoenzyme allocation fraction, φ , on SOC equilibrium, C , in the baseline scenario of temperature dependence. c , Response of SOC ecosystem equilibrium, C , to a 5°C increase in temperature (from 20 °C to 25 °C) as a function of exoenzyme allocation fraction,φ . Parameters are set to their default values (Supplementary Table 1), except \({I=5\ 10}^{-3}\), \(v_{0}^{U}=10^{5}\),\(E_{v}^{U}=38\), \(c_{0}=1.17\).
Figure 2. Effect of microbial evolutionary adaptation on the SOC equilibrium response to + 5 °C warming (EVO effect). Temperature influences enzyme kinetics only (baseline scenario of temperature dependence). a , Influence of microbial biomass production efficiency, γ M, and microbial mortality rate,d M. b , Influence of microbial resource acquisition traits \(v_{0}^{U}\) and \(E_{v}^{U}\). c-d , Influence of competition asymmetry, c 0, and initial temperature, T 0. In all figures, constant parameters are set to their default values (Supplementary Table 1) andI is set to 5 10-3. Points A1 and B1 indicate the default parameter values. Point A2 (respectively B2) exemplifies values of γ M and d M (resp.\(v_{0}^{U}\) and \(E_{v}^{U}\)) for which the EVO effect is strong. Panel c (resp. d ) shows the influence ofc 0 and T 0 on the EVO effect at A2 (resp. B2).
Figure 3. Ecosystem (ECOS) and ecosystem-evolutionary (EVOL) responses of SOC equilibrium to warming (up to + 5 °C) for three scenarios of temperature dependence. Ecosystem and ecosystem-evolutionary changes in SOC equilibrium C given by equation (10) (without evolution, dashed curves) and equation (9) (with evolution, plain curves) are plotted as a function of the increase in temperature. Blue curves , initial temperatureT 0 = 5°C. Black curves ,T 0 = T ref = 20°C.Red curves , T 0 = 30°C. Insets , Direction and magnitude of EVO effect (%), from - 150 % to + 150 %, color code indicates T 0 as before. a , Baseline scenario of temperature dependence (enzyme kinetics only).b , Temperature-dependent microbial mortality, withE dM = 25 < \(E_{v}^{U}\). c , Temperature- dependent microbial mortality withE dM = 55 > \(E_{v}^{U}\).d , Temperature-dependent MGE, with m = 0.014. Parameters values correspond to point B2 in Fig. 2 (\({I=5\ 10}^{-3}\),\(v_{0}^{U}=10^{5}\), \(E_{v}^{U}=38\), \(c_{0}=1.17\)); other parameters are set to their default values (Supplementary Table 1).