How does algae exchange gas with the environment?

Algae exchange gases with the environment primarily through a process called diffusion. Carbon dioxide (CO2) from the surrounding water enters the algal cells, while oxygen (O2), produced during photosynthesis, diffuses out into the water. This exchange occurs directly through the cell membranes, as algae do not have specialized gas exchange structures like those found in higher plants. The efficiency of this process is enhanced by the large surface area of algal cells and their aquatic environment.