Table 3.

Tests for comparing parameterisation or model structure on the difference between ${\delta }^{13}\mathrm{C}$ of A and f _ci.

Case	Test	Changed parameter or formula
a	Standard
b	The effect of pool volume on δ13C A and f ci	Vi: 2e−4, Vc: 6e−4, Fig. 2 and Eqn 1
c, d	The effect of respiration discrimination on δ13C A and f ci	‘high e and f’: e = −1, f = 16, ‘low e and f’: e = −11, f = 6 Ratios $R_d^{13}:R_d^{12}$and $R_p^{13}:R_p^{12}$in Fig. 2; Eqns 12, Supporting Information Eqn S1.3
e	The effect of the release location of respired carbon on δ13C A and f ci	$R_d^j$ and $R_p^j$ to ζi instead of ζc in Fig. 2 $\frac{\mathrm{d}{\zeta }_{i,l}^j}{\mathrm{d}t}=f_{\mathrm{ci}}^j‐f_{\mathrm{cc}}^j+R_{\mathrm{d}}^j+R_{\mathrm{P}}^j$ (Eqn 2) $\frac{\mathrm{d}{\zeta }_{c,l}^j}{\mathrm{dt}}=f_{\mathrm{cc}}^{\mathrm{j}}‐A^j$ (Eqn 3)