Agricultural and climatic changes badly affect the oceans and estuaries. Eutrophication is one such phenomenon observed in aquatic ecosystems where the concentration of nutrients like nitrogen and phosphorus exceeds the average level. Naturally, these nutrients are present at low levels limiting algal and plant growth. The main reason for eutrophication is the leaching of fertilizers and sewage into nearby waters.
Eutrophication is the enrichment of inorganic nutrients in the water, leading to the enhanced production of algae and macrophages. Initially, the algae produce oxygen which seems favorable for fish to thrive. However, algae grow exponentially after a while, forming a sheet of algal blooms on the water surface that appears as a green mat giving off a foul smell and indicating the eutrophic site.
The sunlight fails to penetrate through this layer of overgrown algae and out-compete other organisms living in depth. The algae production exceeds the demand; thus, unconsumed algae die and sink to the seabed. This collection of dead algae and plants motivates the decomposing bacteria to thrive, further depleting the water's oxygen level. Thus, water quality and dissolved oxygen levels drop dramatically, developing a death zone where no organisms can survive.
Eutrophication's intricacies and intricate details make some educators and students feel overwhelmed. To find a solution to this problem, continue reading this article and discover five effective strategies you could implement in your class. These ideas would help make this topic interesting and engaging for your students.
What unseen aspects make eutrophication a tricky topic?
Before diving into the solutions, let's briefly discuss what makes the topic daunting. This complex process is limited and regulated by many factors, making it a content-length and challenging topic for educators and students. The educators often find it tricky to connect all the dots while making the lesson a comprehensive and fun experience.
1. Humans are not always responsible for eutrophication
Eutrophication has been highlighted as environmental havoc caused by human activities; however, it is not always true; it is also a natural process. Students feel overwhelmed to learn that algal blooms can also occur naturally.
The eutrophication rooted in human activities is termed anthropogenic eutrophication, while the one that occurred through natural events is termed natural eutrophication. Farmer's supply fertilizers to the crops intending to enhance production and yield. These fertilizers are rich in nutrients like nitrogen and phosphorous, which get washed away by rains, eventually falling into rivers and lakes. Likewise, deforestation favors soil erosion, leading to soil deposits (rich in phosphorous) in water. As already discussed, these excess nutrients lead to the development of algal blooms in water bodies.
Some lakes are naturally rich in nutrients (eutrophic) which increases with time as the lake gets older. Flood washes nutrients from land and deposits them into the lake or river. It is a relatively slow process that occurs over time; however, temperature change due to global warming speeds up the process.
2. Use of microscope and spectrophotometer
Analyzing water samples for the levels of dissolved oxygen and nutrients is essential to understand the phenomenon of eutrophication. Students at the college/university level are expected to use apparatus like microscopes and spectrophotometers. This adds to the pressure of understanding the problematic biological phenomenon. Some students are reluctant to learn using such a complex device or aren't interested in practical work. Such issues make It hard for educators to deliver such biological phenomena effectively.
3. Additional concepts like the nitrogen cycle
The science behind eutrophication could easily be understood with the precise background knowledge of subjects like the nitrogen cycle, dissolved oxygen level, decomposing bacteria, photosynthesis, etc. Students at the college/university level are familiar with these basic concepts but might not exactly remember the phenomena. It makes them feel uninterested as they’ll have to revise and return to the old concepts.
5 ways to make eutrophication a more approachable topic for students
Eutrophication doesn’t have to be a dull topic for college/university students. Educators could adopt many exciting strategies to make learning fun and approachable for students. We’ll discuss the five most practical solutions and ideas guaranteed to help educators make things easier.
1. Brainstorming to boost engagement
Most students would be familiar with the basic concepts included in the topic of eutrophication but might experience clouded memory. This is an excellent opportunity for educators to increase the engagement rate in their classes. Use the tool of brainstorming and start by asking simple questions. Appreciate all the answers but share correct answers, in the end, to help all students jog their memory. Here are some of the brainstorming questions related to eutrophication.
What is photosynthesis?
What are fertilizers?
Are algae capable of photosynthesis?
What are algal blooms?
What is a microscope, and would you be able to prepare a slide of a given specimen?
Could aquatic organisms survive in polluted water?
What happens when sunlight fails to penetrate the top layer and reach underlying plants?
Start with simple questions and slowly increase the difficulty level to encourage all students to participate in classroom discussions.
2. Seeing is believing
Students are more likely to understand the significance of a scientific event when they experience or see it in person. Most scientific processes are abstract and challenging to visualize. Similarly, the mechanism of eutrophication is also not visible, but the end product (algal blooms and death of organisms) is pretty noticeable.
The field trips to the eutrophic sites filled with algal blooms are efficient and practical strategies. Educators will have to research nearby areas with lakes or estuaries filled with algae and dead fish. Motivate students to collect and bring back water samples making them more interested in the field trip. Some of the most famous sites of eutrophication are as follows:
Mississippi/Atchafalaya River Basin
Kabetogama Lake, Voyageurs National Park
Milford Lake, Kansas
Copco Reservoir in California.
3. Motivate students to check the water quality of samples collected during the field trip
Dissolved oxygen (DO) is the amount of gaseous oxygen dissolved in water. Oxygen diffuses into the water from the surrounding air, by aeration and as a by-product of photosynthesis. Dissolved oxygen levels are used as an indicator of water quality.
Hands-on experience would engage students and help them clearly understand how algal blooms decrease the dissolved oxygen content in water. Introduce different levels of dissolved oxygen and their importance in sustaining life. You are welcome to take advantage of the table below from Labster theory.
The colorimetric method could be used to measure the dissolved oxygen levels in the water sample. The dissolved oxygen test utilizes indigo carmine. In an acidic solution, oxygen oxidizes the yellow-green leuco form of indigo carmine to form a brightly colored blue dye. The resulting blue color is proportional to the dissolved oxygen levels in the water sample.
4. Highlight the effects of eutrophication to help students relate to the topic
Eutrophication poses a significant threat to the ecosystem and biodiversity. Its negative impact is not limited to the animals living in the water. Some land animals and humans might drink the polluted/intoxicated water and fall sick or die. Giving real-life examples make it easier for students to relate to the topic. Here are a few points you could discuss in your class to boost student engagement and interest in the matter.
The inedible and toxic species of phytoplankton and gelatinous zooplankton bloom in the rivers/lakes filled with an algal bloom.
The layer of algal blooms disturbs the water's transparency, color, and odor. The water appears green and murky and becomes difficult to treat.
The population of fish and shellfish is dramatically depleted. The polluted shellfish impact the food chain as they make popular seafood. It causes neurotoxic and diarrhoeic shellfish poisoning.
Loss of valuable biodiversity in rivers is attributed to the process of eutrophication.
The harmful algal species release neurotoxins and hepatotoxins that may lead to health problems.
The invasive species might outcompete native species causing a mass shift in the ecosystem.
5. Use virtual lab simulations
A virtual laboratory simulation is a great way to teach eutrophication. At Labster, we're dedicated to delivering fully interactive advanced laboratory simulations that utilize gamification elements like storytelling and scoring systems inside an immersive and engaging 3D universe.
Check out Labster's simulations for eutrophication. You’ll be able to utilize microscopy and spectroscopy techniques to solve a massive fish-kill mystery. Using these devices as a game-play makes things simpler for students and teachers. Also, you’ll get to investigate how dissolved nitrogen levels and an algal bloom are linked to the fish population.