Table 3 Model variables and parameters
Symbol | Unit | Description | Value |
|---|---|---|---|
Input variables | |||
Q Fe | μmol Fe (mol C)−1 | Total intracellular Fe quota |  |
pH | Â | pH value in medium | Â |
pCO2 | μatm | Partial pressure of medium dissolved CO2 |  |
Parameters to be optimized | |||
\(f_{{\mathrm{Fe}}}^{{\mathrm{PS}}}\) | Â | Fraction of metabolic Fe allocated to photosystems | Â |
\(f_{\mathrm{E}}^{{\mathrm{CF}}}\) | Â | Fraction of produced energy allocated to C fixation | Â |
Constant parameters | |||
\({\mathrm{pH}}_{{\mathrm{bsl}}}\) | Â | Medium pH value under baseline condition | 8.02 |
\(p{\mathrm{CO}}_{2,{\mathrm{bsl}}}\) | μatm | Medium pCO2 under baseline condition | 400 |
\(Q_{{\mathrm{Fe}},{\mathrm{bsl}}}^{\mathrm{c}}\) | μmol Fe (mol C)−1 | Critical QFe for Fe luxury uptake under baseline condition | 24.4 |
OAST | Â | Coefficient representing the strength of OA impact on Fe storage threshold \(Q_{{\mathrm{Fe}}}^{\mathrm{c}}\) | 0.71 |
f ST | Â | Portion of luxury Fe uptake | 90% |
E max | kJ (mol C)−1 d−1 | Maximum cellular energy production rate | 2060 |
\(K_{{\mathrm{Fe}}}^{{\mathrm{PS}}}\) | μmol Fe (mol C)−1 | Half-saturating coefficient for energy production | 35 |
ecCF | kJ (mol C)−1 | Energy consumption rate of carbon fixation | 590 |
f BC |  | Contribution of HCO3− to total inorganic carbon uptake under baseline condition | 80% |
l k | Â | Percentage of total inorganic carbon uptake leaked as CO2 | 50% |
OAlk | Â | Coefficient representing relative reduction of CO2 leakage with increasing medium CO2 | 0.1 |
ecCCM | kJ (mol C)−1 | Energy consumption rate of HCO3− transportation | 60 |
ecAtS | kJ (mol C)−1 | Coefficient representing energy consumption rate for anti-stress | 780 |
ecMT | kJ (mol C)−1 | Energy consumption rate of maintenance | 90 |
ecNF | kJ (mol N)−1 | Energy consumption rate of N2 fixation | 1 110 |
IUEMT | mol C (μmol Fe)−1 d−1 | Fe use efficiency in maintenance | 0.12 |
\(Q_{{\mathrm{Fe}},{\mathrm{ref}}}^{{\mathrm{NF}}}\) | μmol Fe (mol C)−1 | Reference nitrogenase Fe used in representing impact of pH on nitrogenase efficiency | 25 |
NFmax | mol N (mol C)−1 d−1 | Maximum N2 fixation rate | 0.37 |
\(K_{{\mathrm{Fe}}}^{{\mathrm{NF}}}\) | μmol Fe (mol C)−1 | Half-saturating coefficient for N2 fixation | 91 |
\(r_{\mathrm{N}}^{\mathrm{C}}\) | mol C (mol N)−1 | Carbon to nitrogen ratio of Trichodesmium cell | 5.6 |
