where Cc is the CO2 partial pressur

where Cc is the CO2 partial pressure at the reaction site (μbar); ∗ is the CO2 partial pressure at which the carboxylation rate is equal to half the oxygenation rate (μbar); Vcmax is the maximal carboxylation rate (μmol m−2s−1); Kc is the CO2 Michaelis Menten constant (μbar); O is the O2 partial pressure at the reaction site (mbar); Ko is the O2 Michaelis Menten constant (mbar); and Rd is the cellular respiration in light not associated with the PCO pathway (μmol m−2s−1). Note that some of these parameters vary between autotroph species. Values were selected from von Caemmerer and Quick (2000).