Towards the determination of the dissolved CO₂ concentration in aqueous solutions under extreme climatic stress conditions

Abstract

The global carbon dioxide in the atmosphere is predicted to rise due to fossil fuel emissions during the next century. Carbon dioxide is soluble in water and partially dissociates into bicarbonate and carbonate, releasing protons that decrease the pH. This change in pH is expected to play a critical role in some earth systems, such as the hydrosphere, where ocean acidifcation affects the survival of marine organisms. This study used aqueous solutions consisting of water with sodium bicarbonate, Miller’s lysogeny broth, Roswell Park Memorial Institute 1640 medium, and Dulbecco’s Modified Eagle Medium to develop a colourimetric method for the quantification of dissolved carbon dioxide. Various environmental testing conditions were studied using a fuorescent microplate spectrophotometer. The temperature varied between 27 and 42 °C, and the carbon dioxide levels ranged from 0.20 to 10% v/v in the air. The data showed that the amount of dissolved carbon dioxide decreased by 50% in broth solutions, while the reduction in water samples was approximately 18% when the temperature rose from 27 to 42 °C. Furthermore, the composition of the solutions impacted the amount of gas dissolved. The highest amount of dissolved carbon dioxide was observed in the water sample with the lowest salinity, which reached 20,000 ppm CO2 at 27 °C. The lowest amount of dissolved carbon dioxide concentrations was obtained in Miller’s lysogeny broth with the highest salinity level, which reached 1200 ppm under the same conditions. The results obtained can be considered a robust estimation method to calculate the amount of dissolved carbon dioxide under different conditions.