Pollution regulations hit rural areas hardest
Pollution regulations hit rural areas hardest | Image Credit – Herald.Wales

In the present context, we all are fed up with the messy situation of our natural water resources and the waterways. The importance of water is realized when our well is dried. The introduction and dumping of chemical fertilizers, detergents, and sewage in rivers, lakes, seas, and oceans have deteriorated the original water quality. 

Who desires to seek such harsh water conditions? Of course, no one. Due to industrialization and the agricultural revolution, water stress has been a topic of concern today. Who is fully responsible for such disasters? Let’s visualize the topic that concerns cultural eutrophication, causes, impacts, solutions, and the scenario all across the globe. 

Table of Contents

Cultural Eutrophication

Cultural Eutrophication has been an international issue among people regarding the name of aquatic bodies worldwide. It is inferred as one of the forms of water pollution as a cause of anthropogenic-induced interventions. It is the process of water nutrient enrichment in the water bodies, basically nitrogen and phosphorus. 

When there is a disorder in the water quality because of the enrichment of nitrogen and the phosphorus compound, the water becomes impure to thrive for the living creatures for a prolonged period. Cultural eutrophication denotes the human involvement in increasing nutrients, thereby causing the alga increase known as “The Algal Blooming.” 

The primary difference between eutrophication and cultural eutrophication is that eutrophication is the cause of the natural aging process, while cultural eutrophication entails human activities. 

Cultural Eutrophication
Cultural Eutrophication | Image Credit – Flickr

Mechanism of the cultural eutrophication

No doubt, because of the cultural eutrophication, there is an alteration in the ecological water bodies over long years. The whole water cycle gets disturbed from oligotrophic to eutrophic.

There is an ample supply of oxygen to the aquatic creatures in the oligotrophic water bodies. Algal fertilization maximizes algal growth when introducing untreated sewage and industrial effluents into the water resources.  The algal has too specific a span to thrive. 

When it increases massively and dies naturally, the aerobic decomposers increase, creating a higher oxygen demand. Once the oxygen gets higher, it could have detrimental effects and make it difficult for the aquatic organisms, including fish, to survive in the water bodies.

Besides this, the most troubling part is that the microorganisms decompose the organic matter, releasing very harmful gasses such as ammonia and hydrogen sulfide. 

The eutrophication caused by humans occurs when the algae degradation rate by the microorganisms is greater than the oxygen regeneration within aquatic bodies such as estuaries, rivers, lakes, and oceans. 

Excess fertilizers in the runoffs
Introduction of untreated waste material in the river
Animal feeding materials and their operation
Reduction in the water self-purifying capacity
Sewage and industrial effluents
Species invasion
Degradation of recreational opportunities
Food chain and food web
Treatment cost for nitrogen removal in drinking water
Replacing chemical fertilizers with compost manure
Sophisticated technologies
Soil management practices

Sources of the cultural eutrophication

1. Excess fertilizers in the runoffs

Excess fertilizers in the runoffs
Excess fertilizers in the runoffs | Image Credit – Flickr

One of the crucial sources of cultural eutrophication is the fertilizers used extensively. When these fertilizers are swept away by the rain, they are introduced into the water bodies during the runoff. Since the fertilizers possess phosphates, they could undoubtedly deplete the water quality and make them unsuitable for other purposes. 

2. Detergents

Detergents | Image Credit – Wikimedia Commons

Among numerous additives, phosphate is considered significant in detergents. It holds the suspected carcinogens, a harmful chemical known as Nonylphenol, and the various ingredients which hardly get degraded in the environment. The detergents are heavily used in European countries such as France, Hungary, Czechia, Poland, and Portugal, releasing most phosphate. Since it inhibits the biodegradation of organic materials, it deteriorates water quality.

Besides this, detergents also comprise the oxygen-depleting substances that possess cascade damage to the fishes and other aquatic creatures. It looks troublesome to mention that they can destroy the external mucus layer of the fish, which protects them from bacteria and parasites and, thus, damages the gills. 

3. Introduction of untreated waste

Untreated waste
Untreated waste | Image Credit – Flickr

It becomes very substantial to release the industrial effluents and the sewages only after the perfect pre-treatment. You can seek most large factories and industries to introduce their unwanted effluents back into the water without any treatment activities. It can directly ruin the water quality. Those households who rely on the water bodies for washing and rinsing can be affected by poor water quality. 

Causes of the cultural Eutrophication

Phosphorus is one of the significant contributors which stimulates the algal growth in aquatic sources such as rivers, estuaries, coastal waters, and many more. Because of the high amount of artificial matter injection into the water resources, our water resources have been degraded daily. Here is the inclusion of numerous causes of cultural eutrophication throughout the globe, as described briefly.

1. Fertilizers

Fertilizers | Image Credit – Flickr

People often use fertilizers intending to increase their agricultural yield. They use fertilizers, primarily phosphate and nitrate, on the awns, farms cause nutrient enrichment in water bodies. 

The precipitation carries them in the form of rainfall. As a result, there is an increase in the photosynthesis process, causing the growth of the algal blooms and causing oxygen lacing for the aquatic living organisms.   

2. Animal feeding materials and their operation

The larger industrial companies which do produce the animal feeding substances introduce the unwanted higher discharge directly into rivers and the lake. Because of this, there can be an accumulation of the nutrients that target the algal blooms and ultimately triggers eutrophication. Since the water bodies could not hold the organic loads, the blooming of the algae thus degrades the whole water quality. 

3. Reduction in the water self-purifying capacity

Self Purification or Natural Recovery of Water Bodies | Video Credit – Continuous Learning

Over decades, the lakes and the larger rivers have held the massive solid materials that the sediments may transport. As time passes, the basin gets initiated to the full up by the sediment accumulation. Such a natural process could deteriorate the water quality and finally cause eutrophication. 

Thankfully, water itself has a self-purifying capacity. But sometimes, the water could not get self-purified. In such circumstances, the nutrients are overloaded in the water bodies and reflect green color.

4. Sewage and industrial effluents

Sewage and industrial effluents
Sewage and industrial effluents | Image Credit – Pixabay

Industrial effluents infer to the unwanted liquids released from the industries, which have detrimental effects once released into the aquatic bodies without adequate treatment. The release of the industrial effluents directly into the water without treatment is surplus in the developing countries compared to the developed countries. 

The nitrate and phosphate in the untreated industrial effluents and sewages could undoubtedly hamper the water quality and directly threaten the living creatures. 

Image of the industrial effluents discharged into the river via https://www.dreamstime.com/industrial-factory-waste-water-discharge-pipe-canal-sea-water-pollution-industrial-factory-waste-water-image149004144

5. Aquaculture

The current world is undergoing several modern methods and techniques. With the rise in globalization, the rearing of a variety of fish and shellfish species and growing the aquatic plant species lacking in the soil have been visualized as fundamental contributors in the name of cultural eutrophication. It can have detrimental adverse outcomes in commercial aquaculture and pose complications concerning the fisheries and the shellfisheries. 

It is noteworthy to mention that until and unless the aquaculture is not well managed, the fish excretion, food particles, and other various substances initiate to find their way and are finally injected into the water bodies, which creates pollution and a good home for the growth of the microscopic floating plants. 

6. Deforestation

Deforestation | Image Credit – Wikimedia Commons

Upon deforestation, there are likely effects of cultural eutrophication. You cannot deny that trees contribute to holding up the soil tightly. Deforestation at an alarming rate can cause soil erosion, thereby carrying the sediments and other nutrients into the aquatic bodies. It could provide a favorable environment for the success of immense growth of the algal bloom, a biological productivity. 

Impacts imposed by the cultural eutrophication

1. Species invasion

Eutrophication can create a very suitable environment for invading the species. Because of the alteration in the nutrient balance of the water bodies, one species that easily adapts to the changing environment initiates invading the other species within the same water bodies. 

It can restrict proper growth and physical development. Green-blue algae and cyanobacteria blooming could threaten the wildlife and livestock and cause premature aging. 

2. Biodiversity

Threats to biodiversity
Threat to biodiversity | Image Credit – Freepik

Eutrophication imposes several threats to biodiversity. For instance, the nitrogen released from the agriculture of the residential sewages threatens the survival of the coral reefs in the coastal regions. 

The primary threat that has been visualized is a reduction in the calcification, initiating a favorable environment for the significant coral diseases and algae propagation in the corals in the water bodies. It could alter the species composition of the aquatic ecosystem. 

The water bodies comprise several endangered and threatened fish species and macroinvertebrates. Eutrophication makes it challenging to take the oxygen since the oxygen depletes after the eutrophication. 

It could pose several water-borne diseases in the wildlife and decline the species population. The keystone and the sensitive aquatic species may be lost out. As a result, the species may reach the brink of extinction. 

3. Degradation of recreational opportunities

Degradation of recreational opportunities
Degradation of recreational opportunities | Image Credit – Circle of Blue

The enrichment of the nutrients such as phosphate and nitrogen depletes water quality and restricts recreational services. They reduce the transparency in the water. The poor water quality makes the water unfit for various purposes such as swimming, boating, surfing, white water rafting, and water fun parks.

Because of this, it highly affects the national and the international economy/revenue both in inland and the coastal parts. The tourism sector could be drastically affected when no recreational services are carried out in several water bodies such as lakes and rivers. 

4. Food chain and food web

When various chemicals reach the food chain, they can impose health risks on the aquatic organisms that thrive in their natural environment. Ultimately, you can also seek the cascade effect in the food web because the food web relies on the food chain. 

When the primary consumers are affected by the chemicals and the eutrophication induced by the nutrients increases, it can hamper the tertiary consumers overall. You may visualize the significant negative consequences of the prey-predator relationship in the natural ecosystem.  

5. Treatment cost for nitrogen removal in drinking water

The larger water bodies facing the severe eutrophication issue require higher investment in eradicating the algal toxin, algal decomposition products, and, most importantly, nitrogen levels from the water bodies. 

When there is nitrogen presence, the government needs to invest heavily in cleaning up the waterways, thereby dredging and weed-cutting and controlling the excessive nitrogen level. Suppose the water bodies serve drinking water for the nearby communities or the coastal regions. In that case, the water treatment cost may be high to make the water quality free from nitrogen and fit for drinking purposes.

Pros of the cultural Eutrophication

1. Productivity increment

Algae is a food for many fishes
Algae is a food for many fishes | Image Credit – Freepik

Cultural eutrophication indicates nutrient enrichment in the aquatic bodies, causing an algal bloom. In the aquatic ecosystem, most tiny organisms such as fishes rely on algae for their diet. 

Sometimes, the increase in the algal bloom can increase productivity, which may be a huge food source for the fish. Upon getting the appropriate diet at maximum, the fishes and other creatures may proliferate. 

2. Food chain running

The increase in productivity of the algae makes it convenient for the fishes to have their diet at maximum. When there is healthy growth and development of the fishes in the water bodies, the larger fishes could quickly get an opportunity to feed the small fishes. It can no doubt run the food chain cycle with ease and in a perfect way. Nature finds its way to run the natural cycle and balances the ecosystem. 

Solutions to the cultural eutrophication

1. Replacing chemical fertilizers with compost manure

Replacing chemical fertilizers with compost manure
Replacing chemical fertilizers with compost manure | Image Credit – Flickr

Eutrophication is the fundamental cause of the overload of nutrients such as phosphate and nitrogen. The best solution could be the replacement of chemical fertilizers with compost manure. Compared to chemical fertilizers, compost manure possesses less nitrogen and phosphates and can be degraded, restricting the eutrophication process in the aquatic resources. 

2. Sophisticated technologies

Ultrasonic irradiation, one of the technologies, has been extensively used to control eutrophication, causing cavitations that produce free radicals and destroy the algae cells. The other technology entails converting the plant growth to energy and has been used to control eutrophication with ease.

Image of algal bloom control technique via https://www.researchgate.net/figure/Algae-control-techniques-a-chemicals-b-aeration-c-mixing-and-d-ultrasonic_fig4_341481565

3. Soil management practices

The soil should be well preserved, thereby restricting it from degradation. Since the soil determines the suitability of the vegetation, there should be effective management of the soil quality. It is best to keep the soil from contaminating chemicals and other hazardous substances.  

4. Awareness

Awareness | Image Credit – Freepik

Awareness is inferred as one of the best solutions to tackle all the issues and challenges. Considering the case of cultural eutrophication, creating awareness about the impacts of eutrophication is pivotal. When we know its cascade consequences, people will undoubtedly target their activities concerning the water qualities in numerous water resources. 

Concluding Remarks

This article entails information regarding cultural eutrophication, its sources, causes, impacts, and solutions so far. Did you have some ideas about it? Is the article interesting to read since it has become a public concern among us? Don’t you seek the responsibility of we people in keeping our water bodies safe and clean? It’s upon our hands whether to make it messy or protect it for our future generations, thereby preventing eutrophication at both temporal and spatial scales. 

(Last Updated on April 30, 2022 by Sadrish Dabadi)

Kalpana Ghimire holds a post-graduate degree in Environmental Science from Nepal. She possesses numerous research experiences working in water pollution, community forestry, environment conservation status, and wildlife ecology. She was an internee in the Department of Environment (EIA monitoring and auditing section) under the Government of Nepal. Kalpana Ghimire is an avid traveler, an enthusiastic wildlife researcher, and has a huge passion for working in the environment sector. She loves far traveling to the natural areas, conducting field wildlife research and reading the novels.