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Question #45917
The Question
An aquatic ecosystem characterized by an inverted pyramid of biomass experiences a severe, sustained thermal spike. This environmental change leads to a rapid depletion of dissolved oxygen (DO) and a subsequent ecosystem collapse. Which of the following statements correctly identifies the integrated physiological and ecological mechanisms driving this catastrophic collapse?
Options
- A.
The increased temperature enhances oxygen solubility, but the rapid turnover rate of phytoplankton outpaces oxygen production, leading to an algal bloom and hypoxia.
- B.
Oxygen ceases to act as the terminal electron acceptor in the mitochondrial inner membrane of decomposers, forcing a shift to anaerobic decomposition and the release of toxic byproducts.
- C.
The thermal spike decreases the Biochemical Oxygen Demand (BOD) of the water body, causing aerobic benthic organisms to undergo obligate fermentation in their cytoplasm.
- D.
Phytoplankton standing crop exceeds zooplankton biomass due to thermal stress, converting the inverted pyramid into an upright pyramid and permanently halting energy flow.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Terminal Electron Acceptor|Inverted Biomass Pyramids|Primary Productivity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating macroscopic ecological phenomena (eutrophication, BOD, inverted pyramids) with microscopic cellular physiology (ETS, terminal electron acceptor).
The common misconception is treating Ecology and Plant Physiology as isolated units.
Students must recognize that ecosystem hypoxia directly halts the ETS at complex IV (Cytochrome c oxidase) in aerobic decomposers, triggering the anaerobic shift.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Respiration in Plants - Class 11 |
| Concept | Terminal Electron Acceptor |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |