- Farmers use fertilisers that usually contain nitrates and phosphates.
- The leaching of chemical fertiliser from agriculture area to the lake may occur when it rains.
- Increase the fertility of lake.
- Encourages eutrophication (algal growth)
- The growth of algae prevents the light from reaching the base of the lake.
- This reduce and prevents photosynthesis by aquatic plants.
- Reduce the oxygen release.
- Aquatic animals and plants die due to lack of oxygen.
- Decomposition of dead plants, animals and organic matter by bacteria rapidly.
- This will increase the dissolved oxygen content.
- BOD increases the water polluted.
- This cause the aquatic animals die.
Explain briefly about the acid rain phenomenon and its effect to the environment.
EXPLANATION
- Occurs when motor vehicles / factory released large amount of nitrogen oxide
- and sulphur dioxide
- Nitrogen oxide combine with water vapour in atmosphere to form nitric acid.
- Sulphur dioxide combine with water vapour in atmosphere to form sulphuric acid.
- The rain fall as the acid rain.
EFFECT
- May corrode the building
- Acidic water causes aquatic animals die
- Minerals in soil dissolved in water
- Soil becomes infertile / not suitable for plant to growth
- Less yield / plant die because of infertile soil
- The ecological balance of ecosystem distrupt
Explain how ozone depletion occurs. Discuss its effects on human and the environment and suggest the ways to solve this problem.
EXPLANATION
- Thinning of ozone layer is due to widespread use of CFC
- It is used in aerosol, industrial solvents, electronics and in air conditioner
- Ultraviolet radiation strikes CFC molecule cause chlorine atom to break away
- Then chlorine atom collides with an ozone molecule and combines with an oxygen atom to form chlorine monoxide and oxygen.
- Then the free atom of oxygen collides with the chlorine monoxide, the two oxygen atoms form a molecule of oxygen.
- The chlorine atom is released and free to destroy more ozone molecules.
- The chlorine produced re-enters the cycle.
- When the ozone layer becomes thinner, more ultraviolet radiation reaches the Earth.
- Reduction of body's immune system
- Skin cancer
- Eye cataract
- Reduction of rate of plant growth / reducing crop yields
- Death of plankton / Reduce food supply to aquatic organisms
WAYS TO OVERCOME
- Reduce / Stop using CFC or chlorine-based products
- Replace CFC with HCFC
- Use wrapping paper instead of polysterene boxes
Discuss how forest burning causes disasters to the environment.
- Releases a lot of carbon dioxide into atmosphere.
- Carbon dioxide traps heat and causes global warming.
- Releases heavy smoke which reduces light intensity for photoynthesis.
- Smoke particles cause health hazards
- Destroys flora and fauna
- Lost of herbs for medical puposes
- Lost of habitat and extinction of flora and fauna
Explain the effect of an increase in carbon dioxide concentration on the ecosystem.
- Increase in carbon dioxide is due to the burning of fossil fuels in vehicles and excessive cutting down of trees in the forests.
- Increase in the carbon dioxide traps heat.
- Mirrored buildings reflect heat
- which causes a rise in temperature of Earth.
- This phenomenon is called greenhouse effect.
- Industries increase the amount of CFCs and methane in atmosphere and cause global warming.
- It will cause the melting of ice at the poles.
- The sea level rises
- which causes low-lying areas to be flooded.
- It will affect the weather pattern, wind directions and rainfall
- which will affect the yield of crops and water supply.
- The land becomes dry and infertile due to drought.
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