What contributes to the natural purification of surface water?

Natural agencies like vegetation and microbial processes play a crucial role in the purification of surface water. Vegetation along water bodies acts as a buffer, reducing runoff and filtering pollutants before they enter the water. Plants absorb nutrients and contaminants, helping to maintain water quality.

Microbial processes are essential for breaking down organic matter and other pollutants in the water. Beneficial microorganisms in aquatic ecosystems, such as bacteria and fungi, decompose organic substances and can convert nutrients into forms that are less harmful to the ecosystem. This biological activity is vital for maintaining a balanced and healthy aquatic environment.

In contrast, while climate variations can affect water levels and flow patterns, they do not directly contribute to purification. Human activities generally introduce pollutants and can impair natural purification processes. Soil composition can influence water quality, but it is the specific actions of vegetation and microbes that are primarily responsible for the natural purification of surface water.