Eutrophication: Definition, Causes, Ways To Overcome

Table of Contents

Definition of Eutrophication:

It happens



Here are some ways to overcome:

Definition of Eutrophication:

Eutrophication refers to when the environment is enriched in nutrients.

For life to be possible, all living beings require certain nutrients. Natural resources do a great job of providing nutrients, as too few or too many can lead to health problems. Aquatic ecosystems are very dynamic. When there are not enough nutrients, water becomes oligotrophic. It is natural that aquatic environments are oligotrophic if they lack sufficient nutrition for all the organisms.

There are also problems when there is too much nutrients. This is called eutrophication. Eutrophic streams, rivers or lakes can occur when there is too much of a particular nutrients, such as nitrogen or phosphorous. The runoff from the surrounding soil usually causes this. These nutrients are very attractive to plankton, algae and other microorganisms. They can also be a source of food for aquatic organisms. Eutrophication can lead to serious health problems for other organisms (e.g. fish, birds, etc.). What happens? The rainwater is able to wash away excess fertilisers from agricultural land and into nearby ponds or waters. When fertilisers are added to water, the water’s nutrient levels rise. This phenomenon is known as eutrophication. This allows phytoplankton grow faster and reproduces more quickly. Algal blooms will be the result. Algae block sunlight from reaching aquatic plants, so they can’t photosynthesis. The algae and aquatic plants both die, creating sediment at the bottom. This has a negative effect on the ecosystem and encourages detritus growth. The detritus uses up all oxygen in the water and decomposes it. This results in a rise in biochemical oxygen demand (BOD). Many aquatic organisms die when there is not enough oxygen. Algae are responsible for producing toxic bi-products in ponds. These can be harmful to ecosystems. How to determine Bod

A sample taken from a water pond.

BOD can be defined as a high level of oxygen in the sample to allow for organic matter decomposition. This indicates that the water sample is extremely polluted.

BOD rises when water is very polluted with bacteria.

BOD is affected by water that has been contaminated with toxic substances.



Eutrophication is caused by human actions. The human species is dependent on the use of phosphate and nitrate fertilizers. People must fertilize lawns, fields, farms, and courses. When it rains, these fertilizers are emitted into streams, rivers and lakes, as well as the oceans. You provide food for plankton, alga and other aquatic plants. This improves photosynthesis activity. This results in dense plant growth, such as water hyacinths or algal blooms within aquatic environments.

Concentrated animal-feeding operations

Concentrated animal feed operations (CAFOs), are the primary contributors to nitrogen and other nutrients that lead to eutrophication. Concentrated animal feeding operations (CAFOs) usually release high levels of nutrients. It somehow manages to get into the waterways, streams and rivers where they build up in large quantities. The water bodies are afflicted by recurring cyanobacterial/algal blooms.

Direct sewage discharge and industrial waste in water bodies. In the developing countries, sewage water can be directly channeled into rivers, oceans and lakes. This means that there are high levels of chemical fertilizers. This can lead to algal blooms, dense growth and other aquatic plants that could threaten the survival aquatic life.


Aquiculture is a method of growing fish and aquatic plants in water that contains dissolved nutrients. It is a popular practice that has been used in recent years and it qualifies as a major contributor to eutrophication. If aquiculture management is poor, unconsumed foods particles as well as fish excretion could increase levels of phosphates or nitrogen in water. This will cause the growth of microorganisms floating plants.

Nature events

Natural events are also possible to cause eutrophication. Any excess nutrients may be washed away by a stream, river, or lake flooding. In areas where there aren’t fertilized lands nearby, eutrophication may be less likely.

Lake Erie was one of the most well-known examples of eutrophication between the 1960s & 1970s. It was known as “dead lakes”.

The nutrients that were being pumped into the Great Lakes’ smallest and deepest lakes came from urban and agricultural areas. As a result, most species that live in the lake were wiped out by algae and plant growth. It made beaches unusable due to the smell from decaying algae. Consequences

Alarm about the survival and well-being of fish and other aquatic life

When there is an increase of nutrients in the water, photosynthetic and phytoplankton plants grow explosively. This phenomenon is often called algal blooms. Algal blooms cause a reduction in oxygen dissolved, which is essential for the respiration of other animals and plants. Oxygen depletion occurs when the plant or algae life cease to exist and die. Hypoxic levels are reached when dissolve oxygen reaches the water. This can lead to the death of aquatic and plant species as well as animal species. Anaerobic conditions may encourage bacteria growth, which can cause toxins to be harmful for marine mammals and birds. Because of phytoplankton, light penetration is decreased to lower depths. This reduces aquatic life and aquatic dead zones as well as biodiversity.

Bound access and protection from unsafe drinking water.

High levels of toxic algal blooms can be deadly. Anaerobic conditions promote the growth of toxic bacteria. This results in a decrease in clean drinking water availability and a significant deterioration in water quality. The dense growth of photosynthetic bacteria on the water surface and the algal blooms can block water systems. This results in a limited supply of piped water. Many water supply lines around the globe have been affected by toxic algal blossoms. Because of severe algal blooms at Lake Taihu in 2007, over 2 million Wuxi residents were unable access drinking water for longer than one week. Refer to appendix 9

Imperil fishing

Eutrophication is characterised by the increased growth and density of floating plants (photosynthetic bacteria and alga) and the proliferation of dense, floating mats of plants (water hyacinths/Nile cabbage). This is a sign that fishing is at risk in a body of water. When the plants are floating it will make it difficult to fish from the nets. This will also affect the movement and stability of fishing boats.

Mortification of recreational possibilities

Eutrophication is caused by the rapid growth of algal and aquatic plants that float on large areas. It makes it difficult to navigate the lake and reduces transparency. This can lead to a decrease in recreational benefits and opportunities, such as boating and swimming. Water hyacinths can spread across large areas of shoreline. Sometimes it can float across the entire surface to the ground.

Health effects of contaminants

Red tide can also be caused by dinoflagelates, also known as Cyanobacteria. This is a group that releases very strong toxins in water. Anaerobic conditions that result from the growth of explosive plants in water can cause the increase in toxic compounds to double. Even at low levels, the toxic compounds can cause death in humans and animals. Toxic compounds can also be introduced to the food chain, causing various health problems such as cancer. Biotoxins can cause increased incidences of neurotoxic and paralytic in humans, as well as diarrhoetic symptoms in shellfish. This can cause death. Shellfish can build up poison in their muscles, which then poisons humans. High nitrogen levels in water are associated with infants’ inability to stop blood circulation. This is known as blue-baby syndrome. There are ways to overcome this condition:

Making compost

Eutrophication is mainly caused by the excessive use of phosphate and nitrate fertilizers. In an effort to combat this problem, composting is an option. It is the practice of making compost from organic matter like food residues or decaying plants. The compost manure contains nutrients that are deficient in nutrients. This is why water bodies have high levels of phosphates as well as nitrates. The compost fertilizer contains all the necessary elements that are synthesized by plants and then broken down by them. This prevents eutrophication. This is one way to control eutrophication.

Reduced pollution

It is easy and effective to reduce the amount of phosphate or nitrogen that is being released into water systems by limiting pollution.

Large manufacturing companies and municipalities should stop releasing waste into the water system and work to reduce pollution. This will decrease the amount of nutrients, toxins and other pollutants that end up in water supplies. Municipalities and industries that limit the amount of waste and pollution they emit to waterways will reduce their nutrient levels, which can help control eutrophication.

Ultrasonic radiation

Ultrasonic radiation is one method that has been used to control and manage algal blooming in the face of eutrophication. Cavitations can be used to produce free radicals which destroy the cells of algae. Research is ongoing to determine its uniqueness in controlling the problem of eutrophication.

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