FIG 2 .

Percentages of reactions showing different fluxes at doubled HCO₃ levels per group as identified by the solution space sampling of the genome-scale metabolic model of P. tricornutum. Pigment metabolism contains most of the reactions with different fluxes under the two conditions, i.e., 43% of the reactions in this group were upregulated at high HCO₃ concentrations, followed by nucleotide metabolism (19% in total; 17% upregulated and 2% downregulated) and amino acid metabolism (10%). Three reactions, namely, ITCY_c, CMP_c, and ITPA_c, belonging to nucleotide metabolism were downregulated at high HCO₃ concentrations.