Writer: Lava Naz Bagdu
Water scarcity is one of the greatest threats to our age, yet the necessary precautions still need to be taken. People continue to pollute and deplete all the freshwater sources in many ways. One of the most common forms of water pollution is eutrophication. In this article we’re going to explore eutrophication, how it occurs, and its impacts on nature and humanity.
What is Eutrophication?
Eutrophication is a serious environmental problem that occurs in aging aquatic systems like lakes when they get enriched with nutrients such as phosphorus, nitrogen, and other plant nutrients. Leading to the plentiful growth of simple plant life and an increase in phytoplankton (“phytoplankton are microscopic organisms that live in watery environments, both salty and fresh.”). The excessive growth of algae and plankton in a water source is mostly an index of eutrophication. It usually results in the degradation of water quality and the demolition of dissolved oxygen which eventually can make the water a “death zone” since it’s incapable of supporting life anymore. (Byju’s, n.d.; Britannica, 2024; Earth Observatory, 2010)
The diagram shows the eutrophication process, starting with the increase of nutrients which leads to algal blooms, decreased oxygen levels, and loss of food and habitat for aquatic life. (dreamstime.com)
“ Human activities have accelerated the rate and extent of eutrophication through both point-source discharges and non-point loadings of limiting nutrients, such as nitrogen and phosphorus, into aquatic ecosystems (i.e., cultural eutrophication), with dramatic consequences for drinking water sources, fisheries, and recreational water bodies.” (Chislock, et. al., 2013)
Point-Source Discharges
The U.S. Environmental Protection Agency (EPA) identifies point-source discharges as “any single identifiable source of pollution from which pollutants are discharged, such as a pipe, ditch, ship or factory smokestack.” (National Ocean Service, n.d.)
Key Characteristics of Point-Source Discharges:
Identifiable sources: The discharge originates from a specific source such as a factory’s waste pipe, smokestacks, sewage treatment plant, or drainage ditches
Direct impact: Since pollutants are released from a single point, the immediate area around it gets affected the most. Some of these effects are reduced water quality or harm to aquatic life.
In many countries, point-source discharges are regulated under laws such as the U.S. Clean Water Act (“The CWA is the principal law governing pollution control and water quality of the Nation's waterways. The object of the CWA is to restore and maintain the chemical, physical, and biological integrity of the Nation's waters”) (BOEM, n.d.).
Point-source discharges are easier to manage than Non-point loadings since the pollution comes from a single identifiable point, unlike non-point loadings.
Non-Point Loadings
Non-point loadings are quite the opposite of point-source where in non-point, the pollutants are spread over a wide area and do not originate from a single, identifiable source (National Geographic, 2023).
Key Characteristics of Non-Point Loadings
Diffuse nature: Unlike point-source discharges, the pollution originates from many small, widespread areas making it difficult to trace and regulate.
Linked to land use: Non-point loadings are often related to agricultural activities, urban development, or logging which involve large areas of land.
Transported by runoff: Pollutants are carried by water as it flows over the land and into the water bodies, making this dependent on weather events such as rainstorms, or blizzards.
Solutions for non-point loading often include better land management practices, using less fertilizers, controlling erosion, or creating buffer zones of vegetation near water bodies to trap pollutants before they reach the water.
Differences of point and non-point sources (epa.gov)
Eutrophication’s Effects on Nature and Humanity
“Eutrophication sets off a chain reaction in the ecosystem, starting with an overabundance of algae and plants. The excess algae and plant matter eventually decompose, producing large amounts of carbon dioxide. This lowers the pH of seawater, a process known as ocean acidification. Acidification slows the growth of fish and shellfish and can prevent shell formation in bivalve mollusks. This leads to a reduced catch for commercial and recreational fisheries, meaning smaller harvests and more expensive seafood.” (National Ocean Service, n.d)
As a result, eutrophication occurs as one of the massive threats to both aquatic ecosystems and human activities. Still, most people aren't aware of how serious the problem is. To reduce the eventual harm to a minimum, people should be educated about managing land areas and be informed about the possible harm that may, and most likely will occur. If we fail to take immediate action, the health of our water bodies, furthermore our well-being will continue to deteriorate.
References
Eutrophication, Byju’s, (2024.09.06)
Eutrophication, (2024), Britannica
What are Phytoplankton?, (2010), Earth Observatory
Eutrophication Process Illustrations & Vectors, Dreamstime, (2024.09.06)
Chislock, M. F., Zitomer, R. A., Wilson, A. E., (2013), Eutrophication: Causes, Consequences, and Controls in Aquatic Ecosystems, The Nature Education
Point Source, National Ocean Service, (2024.09.06)
Clean Water Act (CWA), BOEM, (2024.09.06)
Point Source and Nonpoint Sources of Pollution, (2023), National Geographic
Addressing Nonpoint Source Pollution through EPA’s National Nonpoint Source Program Webcast, (2023), EPA
What is eutrophication?, National Ocean Service, (2024.09.06)
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