(i) Diatom algae are golden-yellow in color. A complete diatom cell is called a frustule.
(ii) Their cell walls are strong, robust, composed of silica and richly ornamented bilayers.
(iii) They are called the ornaments of the sea or the living spectrum stones as they look very beautiful.
(iv) Dinoflagellate algae produce light in the darkness of night. The phenomenon is called bioluminescence (Noctiluca sp.).
(v) They have 10,000 species in 200 genera.
Some diatoms- Fragilaria capucina, Asterionella formosa, Tabellaria fenestrata, Navicula fossa, Noctiluca miliaris etc.