CBSE Class 10 Answered

Eutrophication is the process by which lakes and streams are enriched by nutrients (usually phosphorus and nitrogen) which leads to excessive plant growth. This reduces the dissolved oxygen content and often causes the extinction of other organisms. The aging process of the lake is accelerated by eutrophication.

The productivity or fertility of such an ecosystem increases as the amount of organic material that can be broken down into nutrients increases. This material enters the ecosystem mainly through runoff that carries debris. Water blooms often develop on the surface, preventing the light penetration and oxygen absorption necessary for underwater life.