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Question #46029
The Question
The pyramid of biomass in a marine ecosystem is typically inverted because the standing crop of phytoplankton is much lower than that of the fishes they support. If a severe environmental stratification causes complete nutrient immobilization in the benthic sediments, which of the following will be the most direct consequence on the ecosystem dynamics?
Options
- A.
The standing crop of phytoplankton will increase due to reduced grazing, making the biomass pyramid upright.
- B.
The inverted biomass pyramid will collapse because the rapid turnover rate of phytoplankton cannot be sustained.
- C.
The pyramid of energy will temporarily invert to compensate for the lack of nutrient upwelling.
- D.
The primary productivity will shift entirely to benthic macrophytes, maintaining the inverted biomass pyramid.
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
Inverted Biomass Pyramids|Standing Crop quantification|Nutrient Immobility
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT fact that 'aquatic biomass pyramids are inverted' without understanding the kinetic mechanism (high turnover rate) that sustains it.
The trap tests the realization that a small standing crop is only viable if nutrient cycling is rapid; if nutrients are immobilized (benthic sink), the turnover ceases, and the inverted pyramid collapses.
Option C exploits the common functional confusion between biomass and energy pyramids.
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 |