Q15.Each year a large amount of plant material, cellulose, is deposited on the surface of Planet Earth. What are the natural processes this cellulose undergoes before yielding carbon dioxide, water and other end products ?

Each year, a substantial amount of cellulose, the primary structural component of plant cell walls, is deposited on Earth's surface. Its natural decomposition is a critical biogeochemical process.

Initial Physical and Chemical Breakdown

Decomposition commences with physical fragmentation by detritivores like insects and worms. This is followed by initial chemical hydrolysis, weakening the cellulose structure.

Microbial Enzymatic Action

Microorganisms, predominantly bacteria and fungi, play a pivotal role. They secrete specific cellulase enzymes that hydrolyze cellulose into simpler disaccharides and monosaccharides.

Aerobic Decomposition Pathway

In oxygen-rich environments, these simpler sugars undergo complete oxidation by aerobic microbes, releasing carbon dioxide, water, and heat energy.

Anaerobic Decomposition Pathway

Conversely, in oxygen-deprived conditions (e.g., wetlands), anaerobic microbes perform incomplete decomposition, generating methane, organic acids, carbon dioxide, and water.

These diverse natural processes are fundamental to the global carbon cycle, nutrient cycling, and soil formation, underpinning ecosystem health.