What is eutrophication?

Eutrophication is the process of excessive enhancing of nutrients, like phosphate and nitrate, in water because of direct deposit of non treated sewage. The nutrients act as fertilizers leading to abnormal proliferation of aquatic algae. With the exaggerated growth of the alga population the number of aerobic bacteria that cause decomposition of organic material also enhances. The proliferation of these bacteria depletes the dissolved oxygen killing fishes and other animals. Besides, the lack of oxygen causes the decomposition to be supposed by anaerobic bacteria. Anaerobes multiply and release hydrogen sulfide that makes water improper to other living beings and makes a putrid smell.