Question

Eutrophication is the natural ageing of lake by

• A. sewage enrichment
• B. nutrient enrichment
• C. physical enrichment
• D. fertilisers enrichment.

Answer 1

The Correct Option is B

Eutrophication is the natural aging of a lake by nutrient enrichment of its water. In a young lake the water is cold and clear, supporting little life. With time, streams draining into the lake introduce nutrients such as nitrogen and phosphorus, which encourage the growth of aquatic organisms. As the lake?s fertility increases, plant and animal life burgeons, and organic remains begin to be deposited on the lake bottom. Over the centuries, as silt and organic debris pile up, the lake grows shallower and warmer, with warm-water organisms supplanting those that thrive in a cold environment. Marsh plants take root in the shallows and begin to fill in the original lake basin. Eventually, the lake gives way to large masses of floating plants (bog), finally converting into land. Depending on climate, size of the lake and other factors, the natural aging of a lake may span thousands of years. However, pollutants from man?s activities like effluents from the industries and homes can radically accelerate the aging process. This phenomenon is called as cultural or accelerated eutrophication.