We grew three phytoplankton species (Prorocentrum micans [dinoflagellate], Dunaliella tertiolecta [green algae] and Ditylum brightwelli [diatom]) in batch culture under three pCO₂ concentrations (ambient [400 ppmv], 750 ppmv and 1000 ppmv) and measured cell sizes, cellular growth rates and nutrient uptake rates. In addition, we measured pH and alkalinity at three times to calculate the pCO₂. These measurements were made to see if there would be morphological or physiological changes in the phytoplankton in the different CO₂ concentrations.