Question

Decomposition of organic nitrogen to ammonium ions is called

• A. Nitrification
• B. Ammonification
• C. Denitrification
• D. Nitrogen fixation

Hint:

Organic Nitrogen \(\rightarrow\) Ammonia = Ammonification (Mineralization).
Ammonia \(\rightarrow\) Nitrite \(\rightarrow\) Nitrate = Nitrification.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The nitrogen cycle in aquatic ecosystems consists of biogeochemical pathways that transform nitrogen compounds into different chemical forms.

Step 2: Detailed Explanation:
- Ammonification: The biological process where heterotrophic bacteria and fungi decompose organic nitrogen (from dead plants, animals, and uneaten fish feed) into inorganic ammonium ions (\(\text{NH}_4^+\)).
- Nitrification: The oxidation of ammonium to nitrite (\(\text{NO}_2^-\)) and then to nitrate (\(\text{NO}_3^-\)) by autotrophic bacteria.
- Denitrification: The reduction of nitrates to nitrogen gas (\(\text{N}_2\)) in anaerobic conditions.

Step 3: Final Answer:
The correct option is (B).