eutrophication

Slow aging process during which a bay, estuary, lake, river, stream, or other shallow body of water deteriorates into a bog or marsh, and eventually 'dies.' Nutritive pollution (containing nitrogen and phosphorous compounds) generated by human activities is a major factor in eutrophication because it causes an explosive growth of algae. Decaying algae consumes the oxygen dissolved in water, ...

Humans need to be more environmentally conscious with our activities because eutrophication can destroy the fish and affect the ocean, as well as ourselves.