EUTROPHICATION
When water bodies such as lakes, estuaries and slow moving streams receive excess nutrients ,it results in excessive plant (algal) growth . This process is called eutrophication. This excessive growth of plants such as Water hyacinth and algae reduces the dissolved oxygen (BOD- biological oxygen demand) in water. The water body then becomes incapable of supporting fishes and other forms of aquatic life. Excessive growth of algae in such water bodies is described as algal bloom. Nitrates and phosphates are the two main substances(nutrients) that causes such condition, which is a direct result of pollution. These nutrients come from a variety of sources,such as fertilizers applied to agricultural fields and golf courses, excessive use if detergents, erosion of soil containing nutrients,untreated sewage and discharges from sewage treatment plants. EUTROPHICATION not only leads to reduced oxygen but also produce foul odour and slow death of water body. Thus, biodiversity in t