Phytoplankton are primary producers in aquatic ecosystems and form the basis of life in these ecosystems. They absorb the sun's light energy by using the pigment in their cell structure and produce organic substances under the photosynthesis phenomenon and using the carbon dioxide in the environment and water, as a result, the sun's light energy is converted into chemical energy. Important economic and ecological values of phytoplankton, are energy production, organic matter, preparation of alginic acid, carrageenan, diatomaceous earth, agar, fertilizer, antibiotic, medical uses, animal and human nutrition, as fodder, and fish food, water reagent is contaminated and transparent. Algae play a small but important role directly in the economy of many countries. Four important economic products are extracted from algae, which are agar, carrageenan, alginic acid and diatomaceous earth. The first two products are extracted from red marine algae (Rhodophytes), the third substance is extracted from brown algae (Phaeophytes) and the fourth substance is extracted from salt and fresh water diatoms. Other direct uses are food for humans and animals, as well as organic and inorganic fertilizers. Summarizing all the economic importance of algae growth is impossible, but based on most considerations, it is estimated that algae play a role in ۵۰% of global carbon stabilization. In aquatic ecosystems, algae are a part of the food chain, and crustaceans and fish feed on it. In agricultural lands, they form an important part of soil flora and are used in wastewater treatment. They play an important role in oxygenation and filtration. Sometimes the growth of algae becomes harmful. This damage causes the production of toxic poisons for fish and other organisms. Some of them are good indicators of pollution in water places. Meanwhile, in some other situations, they themselves can be the polluting factor. For example, Euglena viridis is representative of highly polluted reservoirs, Chlorella vulgaris is representative of moderately polluted reservoirs, and Synura uvella is representative of low pollution reservoirs. In scientific works, they are used as organisms to measure vitamins and the physics of food sources, carbon dioxide absorbers and oxygen providers. They are important tools for research in many physiological processes such as photosynthesis, nitrogen fixation and ionic action.