AIIMS 2008
- Exam
- AIIMS
- Year
- 2008
- Subject
- Botany
- Chapter
- Environmental Issues
AIIMS 2008 · Botany · Environmental Issues
A lake near a village suffered heavy mortality of fishes within a...
A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this?
Options
- ALots of urea and phosphate fertilizer were used in the vicinity.
- BThe area was sprayed with DDT by an aircraft.
- CThe lake water turned green and stinky.
- DPhytoplankton polulations in the lake declined initially thereby greatly reducing photosynthesis.
Correct answer
A. Lots of urea and phosphate fertilizer were used in the vicinity.
Step-by-step solution
Part of fertilizers added to crop fields are passed down to water bodies during rains through surface run-off. Presence of extra nutrients brings about dense growth of plant and animal life. The phenomenon is called eutrophication. Eutrophication leads to organic loading, depletion of oxygen, death of animals and fouling of water.