Difference between phytoplankton and zooplankton

Main difference

The main difference between phytoplankton and zooplankton is that phytoplankton is a microscopic, photosynthetic organism that lives in rivers, lakes, fresh water, and streams, while zooplankton are small aquatic animals that also live in bodies of water, but do not they can produce their own food dependent on phytoplankton.

Phytoplankton vs. zooplankton

Phytoplankton are actually plants, while zooplankton are animals. Phytoplankton synthesize their food in the presence of direct sunlight and are also dependent on minerals, while zooplankton use phytoplankton and other small and large zooplankton for food. Phytoplankton act as the primary producer in aquatic food chains, while zooplankton are known as consumers. Phytoplankton prepare their food by photosynthesis or chemosynthesis, whereas zooplankton cannot produce their food. Phytoplankton release a lot of oxygen into the water while zooplankton do not release oxygen. Phytoplankton use sunlight to feed so they prefer to live near the water surface where there is a lot of sunlight, on the other hand,

Comparative chart

Phytoplankton Zooplankton
Phytoplankton are photosynthetic microscopic autotrophic organisms Zooplankton are heterotrophic organisms
This name comes from the Greek word phyton which means “plant”. « The name zooplankton is derived from the Greek meaning “animal.”
They prepare their own food in the presence of sunlight. They feed on bacterioplankton and other species of zooplankton.
Phytoplankton live near the surface of bodies of water. They live in colder and darker places than oceans and bodies of water.
They can’t move Can move freely
Ecological importance
They serve as food for marine organisms and maintain the stability of marine life. They help to check the level of toxicity of the water body.
Algae, blue-green algae, flagellates and diatoms Crustaceans, radiolaria, ctenophores, krill and mollusks
What is phytoplankton?

Phytoplankton is the microscopic photosynthesizing organism found in the sunny upper layer of all oceans. This name comes from the Greek word phyton which means plant. They are also the main producers of marine life; They get their energy from direct sunlight and prepare food through photosynthesis. Like all other plants, they use sunlight, carbon dioxide, and other nutrients and convert them into carbohydrates and oxygen. They serve as food for marine individuals and maintain the stability of marine life. Phytoplankton are the main source for producing approximately 50% of oxygen from the marine ecosystem, as they release oxygen as a result of photosynthesis. They also vary in different sizes, as they consist of single-celled organisms to organisms found in colonies. They are sometimes known as pastures of the seas. They play a role in food chains. Phytoplankton exist in different sizes; They can be so small that they cannot be seen with the naked eye, and they can also be large.


Algae such as diatoms and blue-green algae, dinoflagellates, cryptomones, true flagellates, and green algae.

What is zooplankton?

Zooplankton are small aquatic animals that live in freshwater lakes and streams. The name zooplankton is derived from the Greek word for animal. They are all mobile. Zooplankton are classified into two categories. One is holoplankton and the other is meroplankton. Holoplankton contain permanent zooplankton such as polychaetes, larvaceans, copepods, etc. Meroplankton includes temporary plankton, for example crustaceans, mollusks, and some small fish. Some of them have the ability to swim against the flow of water like jellyfish and combs. The size of zooplankton can vary from microscopic to more massive than that of a human. They help to check the level of toxicity of the water body. They also play an important role in aquatic food webs as a resource for other consumers.


Radiolaria, foraminifera, crustaceans, ctenophores called comb jellyfish, rotifers, mollusks, and dinoflagellates.

Key differences

  1. Phytoplankton are plants and are known as vagrant plants, on the other hand, zooplankton is an animal.
  2. Phytoplankton are known as autotrophs, since they can produce their food, while zooplankton are known as heterotrophs, since they cannot prepare their own food.
  3. Phytoplankton cannot move freely while zooplankton can move freely.
  4. Phytoplankton are directly dependent on plants, while zooplankton is dependent on phytoplankton and other zooplankton.
  5. Phytoplankton are found on the upper surface of the water, where it receives enough light, while zooplankton prefer darker and cooler places.
  6. Phytoplankton release oxygen into the water, whereas zooplankton do not release oxygen.

Final Thought

The conclusion of this article is that plankton consists of phytoplankton and zooplankton where “Phyto” means plant and “zoo” means animal. Phytoplankton are marine and freshwater plants, and zooplankton are marine animals. Some planktonic organisms are neither plants nor animals, which is why they are known as protists. Both are very important for the stability of marine life. Both help to check the health of the water body.

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