Chrysophytes mainly includes diatoms which occur in aquatic and moist habitats. They may float free or may occur at the bottom. They have gliding type of movement with mucin. They have frustules made of silicon which do not decay easily. They aggregate at the bottom of water table and form diatomaceous earth. It is also known as diatomite.
Frustule has couple of valves known as epitheca and hypotheca. They are basically unicellular and do not posses flagella except in special circumstances like reproduction. They may be bilateral symmetrical or radial symmetrical. Bilateral symmetry is referred as pennate and radial symmetry as centric. Cells are uni nucleate with chloroplasts having chlorophyll a and c. They have a pigment called fucoxanthin especially in diatoms. It imparts brown color to diatoms. Food is stored in the form of oil and polysaccharides. Binary fission is the most common mode of reproduction followed by spores and gametic meiosis. Zygote leads to formation of auxospore.
They are important food producing organisms. They make more than half of the food of aquatic animals. Their dead bodies help in the production of petroleum products. They are inert and are used in filtration of liquid products. They are used in tooth pastes as cleansing agent. They act as an excellent insulating material. They are very good indicators of pollution.
