Question

Excessive accumulation of organic matter in water bodies leads to:

• A. Decrease in species diversity.
• B. Increase in species diversity.
• C. Green house effect.
• D. No effect on species diversity.

Answer 1

Answer: (A)

Decrease in species diversity.

• Organic matter (organic wastes) contains a number of pathogen secondary pollutant pesticides etc.
• Biological oxygen demand becomes high, and therefore the dissolved oxygen reduced. Hence, planktons, molluscs and fishes will be eliminated due to reduced dissolved oxygen and presence of secondary pollutants.
• Some species like annelid worm Tubifex and some insect larvae (Chironomus) survive since they are tolerant to pollution.
• So, the correct answer is option A.