Self purification of water bodies occurs in how many stages?

Self-purification of water bodies is a natural process that occurs mainly through biological, physical, and chemical mechanisms. This process generally involves four distinct stages, which include:

1. Oxygenation: Water bodies receive oxygen from the atmosphere and through photosynthesis by aquatic plants. Oxygen is essential for the survival of aerobic microorganisms that play a crucial role in breaking down organic matter.

2. Sedimentation: This stage involves the settling of suspended solids in the water column. Larger particles sink to the bottom, which helps reduce turbidity and improves water clarity. Sediment can also harbor microorganisms that contribute to the breakdown of pollutants.

3. Decomposition: During this vital phase, microorganisms such as bacteria break down organic matter into simpler substances. Aerobic bacteria use oxygen to decompose organic materials, while anaerobic bacteria take over in oxygen-depleted environments. This microbial activity leads to the reduction of pollutants in the water.

4. Nutrient cycling: In this stage, nutrients released during decomposition (like nitrogen and phosphorus) can be taken up by plants and other organisms, promoting a balanced ecosystem within the water body.

These stages interact with one another and collectively contribute to the purification process, making four stages the correct answer