Also known as hypertrophication, eutrophication refers to the over-enrichment of water with nutrients, especially phosphorus and nitrogen, that leads to an increase in the growth of aquatic plants and algae. For this process to occur, these nutrients have to overwhelm the water body’s capacity to purify itself naturally. This process has several effects, such as a significant reduction in the amount of oxygen in the water. Eutrophication is observed in cases where there is a phytoplankton bloom in a water body due to an increase in the quantity of nutrients. Given the abundance of nutrients like phosphorus and nitrogen throughout the world, all water bodies can experience eutrophication naturally. However, human activities such as modern farming techniques and fertilizer use accelerates the process.
Factors Causing Eutrophication
There are two primary factors that cause eutrophication: human activities and natural processes. Humans affect the eutrophication process through activities such as farming and waste drainage. Fertilizers and other nutrient-increasing substances used in farming can be washed away into water bodies during periods of rain. The discharge of waste into water bodies may also play a part. Both of these processes increase the nutrient content of water, thus leading to eutrophication.
Eutrophication can occur naturally through processes such as sedimentation, which causes water to lose its natural ability to purify itself. A reduction in water’s capacity to purify itself leads to a decrease in the quality of water, and a subsequent increase in the chances of eutrophication occurring.
The Eutrophication Process
An increase in the quantity of algae and aquatic plants in a water body is a sign of eutrophication. This increase leads to a subsequent increase in the biomass of these plants that have to degrade at the end of their lifecycles. For total degradation of these dead plants to occur, the relevant microorganisms require a high amount of oxygen. Due to the high intake of oxygen, an oxygen-free environment is created and microorganisms that depend on oxygen may eventually die out. The role of degrading biomass is passed on to microorganisms that do not require oxygen. This degradation releases toxic compounds, like hydrogen sulphide and ammonia, which may cause the death of plant and animals in the water. This will only occur if the rate of oxygen intake for degradation is higher than the rate of oxygen regeneration, which is usually the case.
Effects of Eutrophication
One of the most obvious effects of eutrophication is an increase in the quantity of inorganic substances, such as ammonia, which is harmful to any organism or plant relying on the water. Additionally, the degradation process leads to an increase in pungent and discolored water due to the degraded or degrading organic substances. These organic substances can form complicated compounds that are harmful to the water. Other effects include a reduction in fish quality, lower income generated by tourism, and other harmful effects.
Prevention and Control of Eutrophication
Prevention techniques include improving the ability of water to purify itself, introducing ecosystems for water filtration, and using better or alternative agricultural methods. When eutrophication has already occurred, techniques for controlling or eliminating the issue include drainage of the most affected water, oxygenating the water, removing phosphorous chemically, and treatment of the water.