Question

Given below are two statements:
Statement (I): When organic fertilizers are used zooplankton will develop through saprophytic food chain.
Statement (II): When inorganic fertilizers are used zooplankton will develop through saprophytic food chain.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Remember:
- Organic Fertilizers \( \rightarrow \) Bacteria \( \rightarrow \) Saprophytic Food Chain.
- Inorganic Fertilizers \( \rightarrow \) Phytoplankton \( \rightarrow \) Autotrophic/Grazing Food Chain.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Fertilizing pond water helps stimulate the growth of natural food organisms (phytoplankton and zooplankton) for cultured fish.
Organic and inorganic fertilizers promote plankton development through different ecological pathways.

Step 2: Detailed Explanation:
Let us analyze both statements:
Statement (I):
Organic fertilizers (such as cow dung, poultry manure, and oil cakes) contain complex organic carbon and nutrients.
When added to a pond, they must be broken down by heterotrophic bacteria and fungi.
This decomposition process initiates a detritus or saprophytic food chain.
The multiplying bacteria form a rich organic detritus that is consumed by protozoans, rotifers, and other zooplankton.
Therefore, when organic fertilizers are used, zooplankton develop primarily through this saprophytic food chain.
Thus, Statement I is correct.
Statement (II):
Inorganic fertilizers (such as urea, single superphosphate, and ammonium phosphate) release dissolved nutrients like nitrogen, phosphorus, and potassium directly into the water.
These dissolved nutrients are absorbed by photosynthetic autotrophs (phytoplankton) to produce energy from sunlight.
The zooplankton then feed directly on this live phytoplankton.
This process initiates a grazing or autotrophic food chain, not a saprophytic food chain.
Thus, Statement II is incorrect.

Step 3: Final Answer:
Statement I is correct, and Statement II is incorrect.
This corresponds to Option (C).