What is the predominant degradation pathway in soil and aquatic sediments?

The predominant degradation pathway in soil and aquatic sediments is microbial degradation. This process involves the breakdown of organic materials by microorganisms, such as bacteria and fungi, which are crucial for nutrient cycling and ecosystem health. Microbial activity is particularly significant in these environments because it leads to the decomposition of organic matter, mineralization of nutrients, and detoxification of harmful substances. Microorganisms utilize various metabolic pathways to break down compounds, making them integral to both soil fertility and water quality.

While oxidation, hydrolysis, and photolysis can play roles in the degradation of certain substances, their impact is often less pronounced in soil and aquatic sediments compared to microbial processes. Oxidation generally requires oxygen and may not be as effective in anaerobic environments like certain aquatic sediments. Hydrolysis typically involves the reaction of water with a compound to split it into smaller molecules, which can occur but is less significant than the widespread and diverse activities of microbes. Photolysis occurs through the action of light, primarily affecting surface layers exposed to sunlight and not as relevant in deeper soil or sediment layers where microbial action dominates. Thus, microbial degradation is recognized as the primary mechanism for breaking down organic materials in these environments.