Phytoplankton grow or 'bloom' very quickly and in huge quantities. These plants multiply rapidly in spring and summer as the daylight hours and temperature increase. Diatoms are the most prevalent species of phytoplankton. It is a member of the largest group of algae. There are more than 12,000 different species of diatoms, and about 100 species inhabit the waters around Antarctica.
Diatoms are circular or oblong shaped.
They are single-celled, and float helplessly in the water or attach themselves with a jellylike substance to stones or other water plants. Diatoms reproduce by cell division. Under some conditions, they can make their own food. They produce their own organic nutrients from the environment, and store food in fatty deposits inside the cell. Diatoms are single-celled algae that add silica to their cell walls for strength.