There is the food chain where each organism is in a producer, consumer, predator, and prey relationship; there is the oxygen cycle and the water cycle that sustains the organisms. When an ecosystem gets polluted, the natural balance in the system is disturbed and this affects the organisms in different ways. It is important to know how a simple act like introducing sewage water or toxic waste into a lake can threaten several life species and plants in the area.
Pollution and the ecosystem
Pollutants like oil, detergents, nitrogen and phosphate from fertilizers and lead can have a tremendous impact on the ecosystem, especially if the water gets polluted. In a lake, for example, it can wreak havoc on the ecological balance by stimulating plant growth and causing the death of fish due to suffocation resulting from lack of oxygen. The oxygen cycle will stop, and the polluted water will also affect the animals dependant on the lake water.
How to study the effect of pollution on an ecosystem
To understand how pollution impacts an ecosystem, select an ecosystem in your neighbourhood. It could be a lake, a river or a sea shoreline. You will need to understand what are the different organisms in the ecosystem and how each organism is related to the other; which level are they in the food chain; how do they adapt to their environment.
Make your project more focused by choosing one or two major organisms in the ecosystems. You will need to track their behaviour, food habits, life cycle, breeding habits and how they are coping with the changes in the ecosystem. Though these changes are usually slow, you can track them over a period of time, say 6 months or one year. Note all your observations and findings, taking care to note down specific details of each species that you are studying.
For the display of the results you can create presentation slides on chart paper or on the computer. Use pictures of the ecosystem and the species you have studied when you discuss each point. You should be able to draw a comparison of the status of the ecosystem before such pollution and its status after the study. You can collect facts about the population of species and migration of other species etc. from your local authorities. The main features that you should cover in your presentation are:
- Name of the pollutants
- Possible source of the pollutants
- Level of pollution
- Effects on the species being studied- food habits, health
- Effects on food chain
- Effects on oxygen cycle
- Effects on water cycle