Phaeophyceae, commonly known as brown algae, owe their characteristic brown or olive color to the pigment fucoxanthin. This is a type of xanthophyll, a class of oxygen-containing carotenoid pigments, that masks the green color of chlorophyll. Rhodophyceae, commonly known as red algae, are predominantly colored by the pigment r-phycoerythrin. This pigment reflects red light and absorbs blue light, which allows red algae to live at greater depths than many other types of algae because blue light penetrates water deeper than light of longer wavelengths. These pigments, along with chlorophylls, not only give these algae their distinctive colors but also allow them to perform photosynthesis by capturing light energy at specific wavelengths.