Which of the following is the Primary consumer in an Aquatic Ecosystem?

Option 3 : Zooplankton

The correct answer is Zooplankton.

Concept:

• Food chain: A food chain shows the feeding relationship between different organisms in a particular environment and/or habitat. A food chain shows how energy is passed from the sun to producers, from producers to consumers, and from consumers to decomposers such as fungi. They also show how animals depend on other organisms for food.
• Tropic level: Based on the source of their nutrition or food, organisms occupy a specific place in the food chain that is known as their trophic level.
• Producers belong to the first trophic level, herbivores (primary consumer) to the second, and carnivores (secondary consumer) to the third. The important point to note is that the amount of energy decreases at successive trophic levels.

Explanation:

• Zooplankton is present on the second trophic level in a food chain in the aquatic ecosystem.
• They are primary consumers as they eat phytoplankton (producers) and are themselves in turn eaten by small fishes (secondary consumers).

Most of the zooplankton are very small microscopic species. For example, single-celled protists that feed mostly on bacteria. However, some zooplankton species can grow quite large such as the jellyfish, arrow worms, etc.

So, Zooplankton is the Primary consumer in an Aquatic Ecosystem.