Collectively, phytoplankton grow abundantly in oceans around the world.
Phytoplankton are microscopic plants that live in the ocean. Like all plants, phytoplankton use the pigment chlorophyll to convert sunlight into food. Phytoplankton differ from land-based plants in that they do not have roots, stems, or leaves.There are many species of phytoplankton, each of which has a characteristic shape.
Because phytoplankton photosynthesises they must therefore live in the well-lit surface layer (termed the euphotic zone) of an ocean, sea, lake, or other body of water. Through photosynthesis, phytoplankton are responsible for much of the oxygen present in the Earth's atmosphere. Two-thirds of all the photosynthesis that takes place on this earth occurs in the oceans that yearly creates 80 to 160 billion tons of carbohydrates.
As the primary producers phytoplankton are at the base of the oceanic food web, Very abundant phytoplankton include the diatoms and dinoflagellates. Among the most abundant are the diatoms. Some 20,000 species make up this plant group. Under favorable conditions, a single diatom can reproduce 100 million offspring in a month. Diatoms are essentially cool water inhabitants, their counterparts in tropical waters are the dinoflagellates.