5 Ways To Make Ecosystem Dynamics Interesting For Students

Ecosystem Dynamics refers to those ingrained ecological processes through which an ecosystem becomes self-regulating, self-sustaining, and capable of recuperation from external pressures. It is also the transformation in ecosystem structure caused by environmental disturbances or by internal forces. An example of ecosystem dynamics is the effect of fertilizer on the phosphorus cycle. The phosphorus cycle is the process whereby phosphorus travels through the lithosphere, hydrosphere, and biosphere, gets disrupted when fertilizers are added to the soil. Fertilizers contain phosphorus, which adds to the phosphorus levels already existing in the soil, and are particularly destructive when such products are washed into local aquatic systems. This turnout of events affects the natural run of the ecosystem.

Figure 1: An extract from ecosystem dynamics simulation by Labster ecosystem activities.

Nutrients are essential for organisms to grow since they form part of many different biomolecules. Photosynthetic organisms, specifically, need different nutrients to grow and flourish. Carbon, nitrogen, phosphorus, sulfur, and potassium compounds are among the most important nutrients for photosynthetic organisms.

As you read, here are some of the questions you'll find answers to:

• How do students learn about the phosphorus cycle in nature?
• How can teachers explain the importance of measuring phosphate in ecosystem dynamics?
• What are the advantages of a virtual laboratory?

Why Ecosystem Dynamics Can Be Challenging 

There are three reasons in particular why ecosystem dynamics can be difficult, even for the most diligent of students.

1. It is difficult to determine when a need arises 

Normally, determining which nutrient limits organisms' growth is not easy. Ideally, we would monitor the concentration of the main nutrients in the soil and analyze if there is a limitation in the supply of any of them. To analyze whether the organisms are limited by any of the nutrients, it is important to focus on any trends. If any of the nutrients decrease constantly over time and reach very low concentrations while the rest of them maintain their concentration and/or experience no decrease, then probably the organisms will be limited by the first.

If it is determined that the organism is limited by one nutrient, in particular, one possible solution is to use a fertilizer that is enriched in the limited nutrition.

The phosphorus cycle occurs at the cellular level. You can’t see or feel it. Not being able to visualize the processes and not seeing their relevance to the real world can make studying it demoralizing and make it hard for students to stay motivated.

2. Its content-heavy

Fertilizers are compounds that are applied to the soil to supply an extra input of one or several nutrients. Fertilizers are used to increase the concentration of certain nutrients in the soil to increase the production of crops.

Fertilizers can be natural (manure) or human-made and have been used by humans for centuries. The prolonged and constant use of fertilizers for extended periods has also caused some environmental problems in human history. The addition of fertilizer may interfere with the natural cycle of elements and cause an (if uncontrolled) eutrophication phenomenon in surrounding water masses.

Before using fertilizers in a big expanse of fields, it is first necessary to assess the impact of this fertilization on the cycle and the possible effect on the surroundings. One possible way to do this is to do a pilot experiment and analyze the cycle before and after adding the fertilizer.

3. It's Complicated 

The phosphorus cycle is extensive, and many different processes and phosphorus fractions are involved. They can be divided into   

• Inputs
• Fractions
• Outputs

Figure 2: Example of the phosphorus cycle

Phosphorus Inputs to the Cycle

The phosphorus that reaches the soil can have four different sources:

1. Atmospheric deposition: atmospheric deposition consists of the small particles (dust) that are transported by the wind and land on top of the soil. Dust particles contain phosphorus and it can be incorporated into the soil.
2. Phosphorus minerals: Many different rocks contain phosphorus in their structure. Rocks are the biggest reservoir of phosphorus in the Earth's crust. This phosphorus can be available for photosynthetic organisms due to weathering of the rocks, and this is the only process that creates "new" phosphorus and makes it available for organisms.
3. Organism residues: Another important input of phosphorus to the soil is the decomposition of corpses or debris from organisms. Corpses of organisms contain organic phosphorus compounds and when they decompose those compounds are released and available to be used by other organisms.
4. Fertilizer: Fertilizers are used to increase the concentration of nutrients in the soil. More information on the Fertilization theory page.

5 Ways To  Make The Concept Of Ecosystem Dynamics Easier For Students To Understand 

With those challenges clearly explained, here are five things you can consider incorporating into your ecosystem dynamics classroom to make teaching more engaging, accessible, and enjoyable for you and your students.

1. The birth of the concept

Ecosystem dynamics as a scientific concept was likely mentioned first by the Evolutionary economist Kenneth E. Building in the late 1970s. His work Ecodynamics which is a multidisciplinary pursuit focused on unveiling the universal patterns in physical, biological, and social science to distill and perceive therefrom, "patterns of space and time…"

2. Relate to the real world

Figure 3: An extract from ecosystem dynamics simulation by Labster ecosystem laboratory activities.

Furthermore, use the known-unknown teaching approach. Address what the students already know about the topic, then tactfully take them through the unknown. This is effective because it won't make students feel they are learning something new; rather, it will only make them build on already existing knowledge. Phosphorus Fractions in the soil: The different phosphorus fractions in the soil are dynamic, which means that, through different processes, they can be transformed from one into another depending on their concentration. The rate at which the transformation of one phosphorus fraction into another occurs depends on the nature of the process, so different processes may occur at different rates.

• Organic phosphorus: The organic phosphorus in the soil consists of humus and the microorganisms living in the soil. Humus is the organic matter that is partially degraded and typically has a dark brown color.
• Soluble phosphorus: Soluble phosphorus is the phosphorus that is dissolved in the water present in the pores of the soil, mainly as phosphate ions. This phosphorus fraction is particularly important because it is the only one that can be directly taken up and used by photosynthetic organisms and is typically the least abundant. 
• Adsorbed phosphorus: The adsorbed phosphorus is the soluble phosphorus that is attached to the surface of certain rocks, such as clays. The phosphate ions attached to the surface of the rock are then immobilized, making them not directly available for living organisms.

Phosphorus Cycle Outputs: Phosphorus can leave a system in three different ways:

• Harvest: Part of the phosphorus can leave the soil due to the harvesting of crops that have been planted. Photosynthetic organisms take up phosphorus from the soil and accumulate it in their tissues, so when they are collected the phosphorus leaves the soil with them.
• Teaching: After rain or irrigation, water can flow through the soil and dissolve part of the nutrients contained in it. Some of his water can sometimes leave the soil in other systems. If this destination system is an enclosed body of water (such as a lake) it can cause an increase in nutrients and ultimately cause eutrophication.
• Runoff and Erosion: After rain or irrigation, part of the water may flow on top of the soil surface and take away part of the nutrients through the dissolution of the nutrients. This is known as runoff.

Erosion refers to the process by which environmental variables (such as wind) may drag particles of soil (containing phosphorus) and transport them out of the original system.

3. Seeing is believing

When a topic is as complex and abstract as ecosystem dynamic, making it visual can make all the difference. Phosphate Measurement Protocol: Phosphate in water samples can be measured using several different methods, but ready-to-measure kits are one of the fastest. Ready-to-measure kits are typically based on colorimetry methods. This means that the analysis is based on the change of color of a substance present in the measuring strip when exposed to phosphate. The more concentrated the phosphate is in the water, the darker the color will be in the strip.

Figure 4: Phosphate strips example.

4. Make it stick with word-play

Knowing the complexity of the teaching of eco-dynamics, these mnemonics will help simplify the concept. An example is "ED-Fsphere" which shows how the movement of the ecosystem when interrupted by fertilizer has adverse effects on the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

ED - Ecodynamics

F -   Fertilizer

Sphere - Lithosphere

              Hydrosphere

              Biosphere

5. Encourage the use of virtual lab simulations

A unique way to teach ecosystem dynamics is through a virtual laboratory simulation. 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 the Labster ecosystem dynamic simulation that allows students to learn through active, inquiry-based learning. In the simulation, students will go on a mission to learn how fertilizers can modify the phosphorus cycle in ecosystems and find a way to increase the yield of crops without impacting the phosphorus cycle and the environment in general.