Which among the following constitute the upper part of the aquatic ecosystem?

Option 2 : Planktons

• Planktons constitute the upper part of the aquatic ecosystem like water.
• Planktons are a diverse collection of organisms that live in large bodies of water unable to swim against the current.
• They provide a crucial source of food to many large aquatic organisms, such as fish and whales.

• Planktons:
  • They are very minute or microscopic organisms freely floating on the surface of the water in a pond, lake, river, or ocean.
  • Planktons float near the surface of the water and provide food for many fish and other aquatic animals.
• There are two types of planktons:
  • Phytoplanktons:
    • The microscopic aquatic plants freely floating on the surface of the water in a pond, lake, river, or ocean.
    • The free-floating alga is an example of phytoplanktons.
    • Phytoplanktons are capable of producing food by the process of photosynthesis.
  • Zooplanktons: ​
    • The microscopic aquatic animals freely floating on water are called zooplanktons.
    • The free-floating protozoa are an example of zooplanktons.
    • A very, very small fish is also zooplankton.