eutrophication

Gradual increase in the concentration of phosphorus, nitrogen, and other plant nutrients in an aging aquatic ecosystem such as a lake. 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. See also water pollution.

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