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Question #46155
The Question
In a closed aquatic ecosystem, excessive nutrient loading leads to a massive algal bloom. Shortly after, a population of aquatic molluscs in this habitat exhibits a sharp drop in hemolymph pH due to metabolic acidosis. Which of the following best explains the physiological mechanism behind this observation?
Options
- A.
Depletion of dissolved oxygen by decomposing bacteria renders the ctenidia in the mantle cavity unable to extract sufficient O2, forcing cellular anaerobic respiration.
- B.
Algal toxins paralyze the radula, preventing the intake of oxygenated water into the mantle cavity and inducing respiratory acidosis.
- C.
Hyperoxia from intense algal photosynthesis over-saturates the ctenidia, leading to the formation of reactive oxygen species that acidify the hemolymph.
- D.
The accumulation of immobile nutrients blocks the osphradium, preventing the excretion of nitrogenous wastes from the mantle cavity and causing uric acid buildup.
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
Mantle_Cavity|Ctenidia|Nutrient_Immobility
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Synthesizing Class 12 Ecology (Eutrophication/BOD) with Class 11 Animal Kingdom (Molluscan anatomy: mantle cavity, ctenidia, radula, osphradium) and Class 11 Respiration (Anaerobic respiration causing lactic acidosis).
Common Misconception: Students often confuse the specific functions of molluscan organs (e.g., assuming the radula or osphradium are involved in respiration) and misunderstand the ultimate cause of mortality in algal blooms (assuming direct hyperoxia rather than decomposition-induced hypoxia).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Mollusca Mantle Cavity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |