UPSC CSE Prelims
Question 37
In the context of ecosystem productivity, marine upwelling zones are important as they increase the marine productivity by bringing the
- decomposer microorganisms to the surface.
- nutrients to the surface.
- bottom-dwelling organisms to the surface.
Which of the statements given above is/are correct ?
View correct answer and explanation
Correct answer: B
Correct Option: B
Explanation: Upwelling brings deep, cool, nutrient-rich water into the photic zone, stimulating phytoplankton and the marine food chain.
Statement / Item-wise Analysis:
1: Incorrect - Incorrect as the primary mechanism: bringing decomposers to the surface does not explain productivity increase.
2: Correct - Correct: dissolved nitrate, phosphate and other nutrients stimulate primary production.
3: Incorrect - Incorrect: moving bottom-dwelling animals upward is not the productivity mechanism.
Option-wise Analysis:
A: Incorrect - includes unsupported item 1.
B: Correct - includes the supported statements and excludes the unsupported ones.
C: Incorrect - includes unsupported item 3.
D: Incorrect - includes unsupported item 3; omits supported item 2.