Q.How is the rate of decomposition affected by the nature of detritus and temperature ?
You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.
Start your 14-day free trial to unlock the full solution →Decomposition proceeds faster when detritus is rich in nitrogen and water-soluble substances (like sugars) and slower when it contains resistant compounds like lignin and chitin; warm, moist conditions accelerate the process, while cold or dry environments slow it dramatically.
The speed at which dead organic matter breaks down is not uniform. Two factors dominate this variation: what the detritus is made of chemically, and the temperature of the environment where decomposition occurs. Both shape how quickly decomposers can do their work.
Nature of Detritus
The chemical composition of dead plant and animal material determines how easily microbes and detritivores can attack it. Detritus rich in nitrogen and water-soluble compounds—sugars, amino acids, simple proteins—decomposes rapidly. These substances are readily accessible to bacteria and fungi; they require little enzymatic effort to break down, so microbial populations multiply quickly and the material disappears fast.
In contrast, detritus high in lignin (the tough polymer in wood) or chitin (the structural material in insect exoskeletons and fungal cell walls) resists decomposition. Lignin is a complex, cross-linked molecule that only specialized fungi can degrade, and even they work slowly. Chitin, though less recalcitrant than lignin, still demands specific enzymes. Leaves from deciduous trees with thin cuticles and low lignin content decompose in weeks to months, while pine needles or woody stems, packed with lignin, may take years.
The NCERT textbook explicitly contrasts these two extremes: nitrogen-rich, water-soluble detritus decomposes quickly, while lignin- and chitin-rich material decomposes slowly.
The carbon-to-nitrogen ratio (C:N ratio) is a useful shorthand. Low C:N ratios mean more nitrogen relative to carbon, which microbes need for their own growth—decomposition is swift. High C:N ratios signal carbon-rich, nitrogen-poor material that microbes struggle to process efficiently.
Temperature
Temperature governs the metabolic rate of decomposers. Microbial enzymes work faster in warmth, so decomposition accelerates in tropical and subtropical climates. The textbook notes that warm, moist environments are optimal: heat speeds up enzyme activity, and moisture keeps microbial cells hydrated and active, while also dissolving nutrients for easier uptake. …
Unlock everything free for 14 days
- Full step-by-step solutions
- Concept-first explanations
- Methods, shortcuts & mistakes
- PYQ mapping + timed mock tests
Full access for 14 days. No credit card required.