Rivers, coastal waters, lakes, tributaries, and even estuaries are at risk due to a process known as Eutrophication. This involves a surge in nutrients, primarily phosphorus and nitrogen, which will lead to an explosive growth of algae referred to as algal blooms.
We can divide eutrophication into two types:
- Natural eutrophication
- Cultural eutrophication.
Natural eutrophication occurs when a basin is filled gradually over centuries with organic and inorganic nutrients along with sediments.
Cultural eutrophication, by definition, occurs when humans impact a water basin by augmenting the input of nutrients so as to yield profound ecological shifts within water bodies over decades.
The cultural eutrophication is principally associated with phosphorus, which is abundant in fertilizers and treated sewage, phosphorus being one of the greatest drivers to algae proliferation. In layman terms, the waters become oversaturated with plant and algal life, to the extent where it harms the environment and the bodies themselves.
The explanation for cultural eutrophication lies within the fact that it stems from human perception – the perception that transparent water with little to no life is preferable to water abundant in life.
Today, with an increased use of phosphates in detergents and fertilizer runoffs, we are facing a greater challenge to our water supply. This phenomenon is known as cultural eutrophication.
In this scenario, an ecosystem utilizes the processes of plants and green algae cyclically to capture and dissolve chemicals, providing a nutritional base to herbivores and carnivores. Dead animals and plant materials are also decomposed by aerobic and anaerobic decomposers into simple forms that can be easily recycled into the natural cycles.
Still, water bodies have no problem with the recycling of matter it, maintaining water quality. In cultural eutrophication, however, a larger amount of artificial matter is put into the water ecological system, bypassing the cycle, which leads to eutrophication of the water body that has previously been oligotrophic.
Where the oligotrophic water bodies differ from eutrophic, abundant with algae, is that they contain a higher supply of oxygen. An example of a human approach to damaging the ecology is uncontrolled dumping of sewage into a water body. This uncontrolled discharge of sewage fertilizes algae, thus increasing their growth.
When algae increase, the aerobic decomposers multiply, creating a greater consumption of oxygen in the water. If there is too much oxygen demand, the available oxygen will not be able to meet the demand which would make survival difficult for fish and other aquatic organisms.
In the absence of oxygen, some harmful microorganisms capable of existing without oxygen would begin to decompose organic substances and in the process, emit hydrogen sulfide and ammonia. This is how the process of cultural eutrophication works.
Various Causes of Cultural Eutrophication
Some of the common causes of human-induced eutrophication include:
1. Fertilizers.
Fertilizers are usually the main reason for eutrophication. Use of fertilizers, especially nitrate and phosphate fertilizers used on farms, lawns, and even golf courses, results in blocks of accumulated phosphate and nitrate in water bodies.
Once such nutrients reach oceans, lakes, rivers, and other water sources, plankton and algae, and other aquatic plants circulate very actively and would tend to multiply, greatly increasing their photosynthetic activities.
Photosynthesis activity contributes to the excessive growth of algal blooms and other flora. This excessive growth shall result in a reduced concentration of oxygen in water, and this would trigger the eutrophication process.
2. Concentrated Animal Feeding Operations.
Concentrated Animal Feeding Operations (CAFOs) have a huge output of artificial nutrients into rivers, lakes and oceans. These nutrients are able to blend and mix causing water bodies to have the issue of algal blooms as well as cyanobacteria.
3. Sewage and Industrial Discharge
Many primary and developing towns do have access to untreated industrial sewage which could be an easy access point for water bodies and lead to the overwhelming growth of algal blooms and plants, which in turn, may overpower the aquatic life in various ways.
Even after being treated, water should never be discharged back into water bodies as it leads to an accumulation of nutrients in the water.
4. Aquiculture
Modern methods of growing shellfish and fish alongside aquatic plants without soil is further accelerating the rate of cultural eutrophication in modern society.
Without proper control in aquculture, feed and waste by fish are able to escape into the water and subsequently support rampant growth of smaller floating plants.
5. Deforestation
The harvesting of trees increases the chances for eutrophication. Trees serve an important purpose in maintaining soil structure.
Once trees are removed, soil is eroded, which leads to the washing away of silt and other nutrients into water bodies, which is conducive to the rapid development of algae blooms.
Effects of Cultural Eutrophication
Some of the common impacts bearing eutrophication with them include;
1. Deterioration of Water Quality
The first and foremost is the decline in water quality. Eutrophication causes algae to grow, which in turn deteriorates the water quality. In comparison to eutrophic water, human beings prefer clear and clean water.
Some people using nutrient-rich water sounds ludicrous. For example, if a water source is polluted, people that depend on rich waters would have to wait for the water to improve in quality before they can use it.
The blooms of algae and their toxins is another factor that should be considered as well. It should also be noted that algae become more toxic in an anaerobic environment. Algal blooms reduce the amount of fresh drinking water available.
Moreover, the enhanced growth of algal blooms and other vegetation can lead to blockage of the water supply systems, which greatly reduces the supply of piped water.
2. Threatens Survival of Aquatic Life
One commonplace feature of eutrophication is the dramatic increase in phytoplankton and plant life. The dramatic increase in vegetative life results in a higher use of oxygen and, consequently, the availability of dissolved oxygen for breathing by other plants and animals in the water gets severely decreased.
In addition, dying and decomposing algae continue to use oxygen, further perpetuating the cycle of asphyxiation for fish and other aquatic life. It creates conditions for the proliferation of bacteria that are poisonous to sea life and birds and are incapable of being neutralized once the water has reached a saturation point of being devoid of oxygen.
3. Poisoning
Eutrophication intensifies the spread of cyanobacteria, a type of bacteria capable of causing a red tide which pours out highly poisonous toxins into water. Even a concentration too minute is enough to be lethal. Eutrophication has also shifted the balance towards toxic compounds in any body of water.
At even the faintest trace of this toxin in drinking water, it is capable of resulting in death to humans and animals alike. It can also result in other health problems such as different forms of cancer due to bio-accumulation and bio-magnification through the food chain.
For instance, shellfish poisoning is an example of where eutrophication is relevant. Shellfish, due to their filter-feeding, accumulate poison in their muscles which then get transferred to humans. Infants are also at risk because high concentrations of nitrogen in water may cause them to have blood circulation problems.
4. Inhibit Fishing
Eutrophication stimulates the growth of algae, small plants, and photoautrophic bacteria. Sometimes called the “green revolution”, uncontrolled growth of algae and plants can result in dense, extensive mats of floating vegetation that impede the setting of fishing nets in the water. They can also restrict the movement of boats and other fishing crafts.
5. Degradation of Recreational Opportunities
Algal blooms and other plants can be extensively spread so that they lower the clarity of the water as well as its navigable waters, thereby reducing the recreational values and uses of these water bodies. The growth, especially on the surface, will slow down activities like boating and swimming.
Solutions to Cultural Eutrophication
Some of the solutions to cultural eutrophication include the following:
1. Managing Water Pollution
Since pollution is undoubtedly the major causative factor of eutrophication, its control in its manifold forms can help alleviate further damage to water bodies. Reducing discharges of nitrogen and phosphates into water bodies can assist in minimizing the concentration of nutrients in the water body system and therefore control eutrophication.
However, this solution would depend on collaboration among industries, municipalities, and individuals in pollution abatement. There is little benefit if industries reduce their pollution, but municipalities continue to contaminate water bodies.
2. Composting
Since pollution is undoubtedly the major causative factor of eutrophication, its control in its manifold forms can help alleviate further damage to water bodies. Reducing discharges of nitrogen and phosphates into water bodies can assist in minimizing the concentration of nutrients in the water body system and therefore control eutrophication.
However, this solution would depend on collaboration among industries, municipalities, and individuals in pollution abatement. There is little benefit if industries reduce their pollution, but municipalities continue to contaminate water bodies.
3. Create and Strengthen Non-Point Pollution Laws
There is a need for governments to legislate and develop policies against non-point pollution. According to the EPA, a major difficulty in controlling eutrophication lies in non-point pollution.
Controlling nutrient sources can significantly limit eutrophication, which means that governments and municipalities across the world should implement measures aimed at reducing on-point pollution.
Less non-point pollution leads to a lower eutrophication nitrogen and phosphorus is fed into water systems. These measures should promote higher water quality target levels and lower pollution levels.
4. Ultrasonic Irradiation
Developers in conjunction with scientists have already or are in the process of devising means aimed at mitigating pollution or even restoring the- unfortunately- already inflicted damage during the past few years.
As an example, ultrasonic irradiation made great strides towards mitigating eutrophication, as the technology produces cavitation which creates free radicals capable of destroying algae. The technology has been instrumental in accomplishing this.
There has also been progress in other types of technology which convert biomass from water bodies into energy. However, though these inventions are still quite costly, they do set the foundation for combating decades of harmful pollution leading to cultural eutrophication.
In this regard, it is imperative for governments to also turn their attention toward funding and offering support for novel technologies that address notable environmental issues.