In addition, as these organisms grow, their predators and other organisms that live on their decayed materials also grow and deplete the oxygen supply. Consequently, other aerobic organisms such as fish starve for oxygen and die. This phenomenon is known as eutrophication. Phosphate - the growth of organisms such as algae and cyanobacteria, that fix their own carbon and nitrogen, is limited by phosphate. Thus if a phosphate source is introduced into the environment, these primary producers will proliferate and eutrophication may occur.
Fertilizers are rich in such nitrogenous materials.
The main point is that releasing untreated, nutritious materials into the environment may favor the growth of certain microorganisms, upset the normal balance of ecosystems, and kill many larger creatures that require oxygen to live, such as fish. B. Water-Borne Pathogens 1. Contamination may occur by accidental mixing of water flowing through pipes having treated and untreated water. Many countries have poor or non-existent water treatment facilities. It is wise to avoid the various sources of polluted water.