14/05/2022
Causes of Eutrophication
1. Fertilizers (nitrates and phosphates)
Eutrophication is predominantly caused by human actions due to their dependence on using nitrate and phosphate fertilizers. Agricultural practices and the use of fertilizers on lawns, golf courses and other fields contribute to phosphate and nitrate nutrient accumulation.
When these nutrients are washed by surface runoff into lakes, rivers, oceans and other surface waters when it rains, the hungry plankton, algae and other aquatic plant life are well fed, and their photosynthesis activity is increased. This causes a dense growth of algal blooms and plant life, such as the water hyacinths in the aquatic environments.
2. Concentrated Animal Feeding Operations
Concentrated animal feeding operations (CAFOs) are as well the main contributor of phosphorus and nitrogen nutrients responsible for eutrophication.
The concentrated animal feeding operations normally discharge high scores of the nutrients that find a way into rivers, streams, lakes and oceans where they accumulate in high concentrations, thereby plaguing the water bodies by recurring cyanobacterial and algal blooms.
3. Direct Sewage Discharge and Industrial Waste into Water Bodies
In some parts of the world, especially the developing nations, sewage water is directly discharged into water bodies such as rivers, lakes and oceans.
As a result, it introduces high amounts of chemical nutrients, thereby stimulating the dense growth of algal blooms and other aquatic plants, which threatens the survival of aquatic life in many ways.
Some countries may also treat the sewage water, but still discharge it into water bodies after treatment. As much as the water is treated, it can still cause the accumulation of excess nutrients, ultimately bringing about eutrophication. The direct discharge of industrial wastewater into water bodies presents similar outcomes.
4. Aquiculture
Aquiculture is a technique of growing shellfish, fish and even aquatic plants