Eutrophication

Eutrophication is the overproductivity of algae and aquatic plants which eventually lead to the removal of the life-supporting qualities of the ecosystem.

[|Causes]:
 * natural runoff of nutrients from the soil and the weathering of rocks;
 * runoff of inorganic fertilizer containing nitrates and phosphates;
 * runoff of manure from farms containing nitrates, phosphates and ammonia;
 * runoff from erosion following mining, construction work or poor land use;
 * discharge of detergents containing phosphates; and
 * discharge of partially treated or untreated sewage containing nitrates and phosphates.

Main nutrients that cause eutrophication are phosphorus, nitrogen, and other organic growth substances.

An example of eutrophication is the algae blooms off the coast of Maine. As the nutrient runoff from Maine travels into the bodies of water, the algae in the water's population increases substantially. Eventually the algae die and sink to the bottom of the water. Their decomposition uses up oxygen in the bottom of the ocean. This lack of oxygen forces fish to swim up and creatures who live on the ocean floor to die.