Background Information
Eutrophication occurs when bodies of water—such as oceans, rivers, and lakes—become overly enriched with nutrients like nitrogen and phosphorus (Akinnawo, 2023). These nutrients often originate from agricultural fertilizers, industrial waste, and untreated sewage. During rainfall, these substances are carried into water systems through runoff. Farmers frequently use fertilizers rich in nitrogen and phosphorus to boost crop yields and support the growing global population. However, these nutrients do not always stay on the fields where they are applied. Instead, excess nutrients are washed away during rain events, entering streams and rivers, and ultimately flowing into larger bodies of water like oceans (US EPA, 2022). This nutrient overload leads to algal blooms and other environmental impacts, significantly disrupting aquatic ecosystems.
Eutrophication is a significant environmental issue in Finland, affecting its lakes, rivers, and coastal areas, particularly the Baltic Sea (Schiewer 1991). Finland has implemented measures to combat eutrophication, such as promoting sustainable farming practices, improving wastewater treatment, and participating in international initiatives like the Baltic Sea Action Plan (HELCOM 2021) While progress is being made, continued efforts are needed to protect Finland’s water resources and marine ecosystems.
Activity Studying Eutrophication
1. Gather three equal-sized mason jars, pond water, a graduated cylinder, a pipette, and microscope slides for the experiment.
2. Half-fill each of the three jars with equal amounts of pond water, ensuring consistent volume across all jars.
3. Stir the water in each jar before placing a drop from any jar onto a microscope slide.
4. Using a microscope, count and estimate the number of visible algae cells in each water sample.
5. Hold each jar against a white sheet of paper and observe the color of the water, noting any differences.
6. Decide on administering treatments: control (no treatment), “press” (continuous disturbance), and “pulse” (short-term disturbance).
7. Determine the concentration of fertilizer to be used for the “press” and “pulse” treatments.
8. Set the duration of the experiment and decide how often to check the results.
9. Regularly check and record observations for the control, “press,” and “pulse” treatments over the set period.
ii. Measurement of Oxygen in Water
1. Obtain a calibrated oxygen meter, a small amount of fertilizer containing phosphorus and nitrogen, and a pond water sample.
2. Use the oxygen meter to measure and record the initial oxygen levels in the water sample.
3. Add a small quantity of fertilizer to the water and then measure the oxygen levels again.
4. Repeat the process daily for one week as algae begin to grow, monitoring the effects of eutrophication on oxygen levels in the water.
iii. Measurement of Temperature Difference
1. Take 500 mL of water and divide it equally into two samples.
2. Place one water sample in direct sunlight and the other in a shaded area.
3. Over the course of 7 days, measure the oxygen content in both water samples daily. 4. After 7 days, compare the two samples to observe how higher temperatures may accelerate the effects of eutrophication, focusing on differences in oxygen levels and water quality.
The Future of Eutrophication and How to Address It
The impacts of eutrophication are already being felt globally, and this problem could worsen if effective measures are not taken. Here’s what eutrophication might cause in the future and how we can mitigate its effects.
i. What Could Eutrophication Cause?
Eutrophication leads to an excessive nutrient buildup, particularly nitrogen and phosphorus, which fuels the overgrowth of algae in aquatic environments. Although nutrients are essential for plant life, an overabundance causes uncontrolled algae blooms. These algae block sunlight, harming aquatic plants. When the algae die, bacteria decompose them, consuming large amounts of oxygen in the process. This creates low-oxygen (hypoxic) conditions that are incapable of supporting most aquatic life forms, leading to “dead zones” in water bodies where few organisms can survive (Luna Juncal et al., 2023).
ii. Coral Bleaching
Coral reefs, which support thousands of marine species, are threatened by eutrophication. Excessive nutrients from runoff can trigger algae growth that suffocates corals, leading to coral bleaching. As corals bleach and die, biodiversity declines, negatively affecting species that rely on coral reef systems for shelter and food (Willige, 2024).
iii. Accelerated Global Warming
When algae decay, they release methane, a potent greenhouse gas that traps heat in the atmosphere more effectively than carbon dioxide. The release of methane from decaying algae contributes to global warming, exacerbating climate change and causing rising temperatures (Willige, 2024).
iv. Decline in Marine Diversity
As oxygen levels plummet due to eutrophication, fish, crabs, and other marine life may die, causing a significant decline in marine biodiversity. Entire ecosystems may collapse, leading to the loss of species diversity and disruption of ecological balance, which could result in lasting devastation (Luna Juncal et al., 2023).
v. Starvation of Fishing-Dependent Societies
Eutrophication poses a threat to communities that rely on fishing as their primary source of food and income. A decline in fish populations due to dead zones can lead to food shortages and economic hardship, particularly in coastal regions of Southeast Asia, Africa, and Latin America, which are already vulnerable to food insecurity.
vi. Increased Flooding Due to Coral Loss Coral reefs act as natural barriers that protect coastlines from storms and wave surges. When corals die due to eutrophication, this protection diminishes, making coastal areas more vulnerable to flooding from storms, hurricanes, and tsunamis. The destruction of coral reefs can lead to devastating floods and damage to coastal communities.
How Can We Help?
i. Corporate Efforts
Several companies are taking action to reduce the amount of nitrogen and phosphorus that enters waterways. Agricultural firms are developing precision farming techniques to help farmers use fertilizers more efficiently, reducing runoff. Additionally, advancements in wastewater treatment technology are helping to ensure that sewage and industrial waste are treated before they enter water systems. The U.S. Environmental Protection Agency (EPA), for example, has launched initiatives to reduce nutrient pollution in key areas such as the Chesapeake Bay and the Gulf of Mexico (US EPA, 2022).
ii. Donate
Supporting environmental organizations involved in wetland restoration can make a difference. Wetlands act as natural filters that remove excess nutrients from water, reducing the effects of eutrophication. Donations to organizations involved in advocacy and conservation can help expand these efforts and ensure stronger environmental regulations are enforced.
iii. Direct Action
Individuals can make an impact by participating in local river or beach cleanups and spreading awareness about nutrient pollution. Small changes, like reducing personal fertilizer use, planting buffer strips around farmland, or choosing sustainably produced goods, can collectively help reduce nutrient runoff and prevent eutrophication (Walker, 2019).
In summary, eutrophication poses a serious threat to aquatic ecosystems and human societies, but with concerted efforts from governments, industries, organizations, and individuals, we can mitigate its effects and protect the environment for future generations.
References:
Akinnawo, S. (2023). Eutrophication: Causes, Consequences, Physical, Chemical and Biological Techniques for Mitigation Strategies. Environmental Challenges, 12(2667-0100), 100733–100733. https://doi.org/10.1016/j.envc.2023.100733
HELCOM (2021) Baltic Sea Action Plan. Baltic Marine Environment Protection Commissison 1–101. http://helcom.fi/Documents/Baltic %5Cnsea action plan/BSAP_Final.pdf
Schiewer U (1991) Eutrophication of the Baltic Sea Foreword. Internationale Revue der gesamten Hydrobiologie und Hydrographie 76:293–294. https://doi.org/10.1002/iroh.19910760302
Luna Juncal, M. J., Masino, P., Bertone, E., & Stewart, R. A. (2023). Towards nutrient neutrality: A review of agricultural runoff mitigation strategies and the development of a decision-making framework. Science of the Total Environment, 874, 162408. https://doi.org/10.1016/j.scitotenv.2023.162408
US EPA. (2022, October 28). The Sources and Solutions: Agriculture. US EPA; United States Environmental Protection Agency. https://www.epa.gov/nutrientpollution/sources-and-solutions-agriculture
Walker, S. (2019). In World That Says It’s Cutting Nutrient Pollution, Progress Is Lacking. Www.wri.org. https://www.wri.org/insights/world-says-its-cutting-nutrient-pollution-progress-lacking
Willige, A. (2024, May 29). What causes coral reef bleaching? World Economic Forum. https://www.weforum.org/agenda/2024/05/coral-reef-bleaching-global-warming/
