However, increased atmospheric CO2 levels, accompanied by increased dissolved inorganic carbon (DIC), can similarly increase the nutrient uptake rates of U. lactuca and enhance the photosynthesis of this alga . Although increased CO2 concentrations, simultaneously with increased DIC, have been documented to have a considerable influence on G. lemaneiformis and U. lactuca, the physiological impacts of CO2 levels on the interspecific competition between G. lemaneiformis and U. lactucafor growth and photosynthesis need to be understood.