Estimation of αCO_2 and pKapp of hemolymph acid-base balance in Mytilus coruscus between 16℃ and 28℃

The influence of temperature on the hemolymph CO_2 solubility coefficient (αco_2) and the apparent dissociation constant of carbonic acid (pKapp) in Mytilus coruscus was investigated. Mytilus coruscus hemolymph was equilibrated with standard CO_2 gas mixtures to obtain expressions for αco_2 and pKapp as a function of temperature. The relationship between αco_2 and temperature (T) is expressed as follows： αco_2 = 138.247 – 11.253 • T + 0.554 • T^2 − 0.0140 • T^3 + 0.000138 • T^4. The following relationship between pKapp and temperature was found： pKapp = 6.6407 – 0.01589 • T . The parameter units are ℃ for T and µM/L/torr for αco_2. These equations enable estimation of hemolymph αco_2 and pKapp at arbitrary temperatures and simple calculation of Pco_2 and [HCO_3^–].