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Question #46025
The Question
In a highly productive terrestrial ecosystem, a massive shedding of leaves results in a sudden influx of detritus exceptionally rich in lignin and chitin. Shortly after, the surrounding plants begin to exhibit severe nitrogen deficiency, despite the large addition of organic matter to the forest floor. Which of the following ecological phenomena best explains this paradoxical observation?
Options
- A.
Rapid mineralization of the detritus, which causes immediate volatilization and loss of nitrogenous compounds from the soil.
- B.
Sequestration of available inorganic soil nutrients by decomposing microbes, leading to a state of nutrient immobilization.
- C.
Complete cessation of the fragmentation step by detritivores due to the high tensile strength and toxicity of lignin.
- D.
Accelerated leaching of water-soluble inorganic nutrients driven by the hydrophobic nature of the accumulated chitin.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Humification vs Mineralization|Decomposition Rate Modifiers
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often harbor the misconception that adding organic matter (detritus) to soil always immediately increases its fertility.
The trap lies in failing to integrate two distinct NCERT concepts: 'factors affecting decomposition rate' and 'nutrient immobilization'.
Students must recognize that high-lignin detritus creates a high microbial demand for inorganic nutrients, turning the microbes into competitors with plants for soil nitrogen.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Nutrient Immobility |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |