Q. What do you mean by eutrophication?

The Eutrophication is the process of excessive increasing of nutrients, like nitrate and phosphate in water due to direct deposit of non treated sewage. The nutrients proceed as fertilizers leading to abnormal proliferation of aquatic algae. With the exaggerated expansion of the alga population the numbers of aerobic bacteria that cause decomposition of organic material also enhance. The proliferation of these bacteria depletes the dissolved oxygen killing animals and other fishes. Further, the lack of oxygen causes the decomposition to be assumed by anaerobic bacteria. The Anaerobes multiply and release hydrogen sulfide that makes water improper to other living beings and creates a putrid smell.