Control and Management

The BiosphereSG Biology

Learning Outcomes 1

• State that pollution affects air, fresh water, sea and land.

• State that the main sources of pollution are domestic, agricultural and industrial, giving an example of a pollutant from each.

• Give an example of one way in which pollution may be controlled.

Pollution is caused by the presence of a substance that is harmful to an animal or a plant, it can affect freshwater, sea, land and air.

Sources of Pollution

Pollutants come from 3 main sources:

o Industrial Pollution

o Agricultural pollution

o Domestic pollution

Agricultural Pollution

• Crops sprayed with pesticides

• Pesticides wash off and reach the rivers

• This damages the river habitat and kills organisms.

Industrial Pollution• Most of our electricity

comes from power stations which burn fossil fuels.

• Fossil fuels release harmful gases into the air when they are burned, e.g.– Sulphur dioxide– Nitrogen dioxide

• When there gases dissolve in rainwater they form acid rain.

Acid Rain

Acid Rain

• Acid Rain– Kills fish and trees– Damages buildings, especially limestone– Falls into lakes and poisons fish and birds

Questions – Acid Rain

1. What is acid rain?2. Why is 'acid rain' a misleading term?3. What two elements are responsible for acid

rain?4. What human activities cause acid rain?5. What effects does acid rain have on

humans?6. What effects does acid rain have on trees

and plants?7. What effects does acid rain have on

buildings and structures?

Domestic Pollution

• Domestic rubbish• Old car parts• Car exhausts release toxic gases to the

air.

Controlling Pollution

Pollutant Method of Control

Soot in smoke

Lead in exhaust fumes

Domestic sewage

Controlling Pollution

Pollutant Method of Control

Soot in smokeClean Air Act prohibits factories from releasing black smoke.

Lead in exhaust fumes

Domestic sewage

Controlling Pollution

Pollutant Method of Control

Soot in smokeClean Air Act prohibits factories from releasing black smoke.

Lead in exhaust fumesIntroduction of lead free petrol

Domestic sewage

Controlling Pollution

Pollutant Method of Control

Soot in smokeClean Air Act prohibits factories from releasing black smoke.

Lead in exhaust fumesIntroduction of lead free petrol

Domestic sewageTreatment at sewage works before waste is discharged

Quick Test

1. Name the three main sources of pollution.2. Name four parts of the environment that

pollutants affect.3. Name a gas which causes acid rain.4. Name an agricultural chemical that can

cause pollution.5. How can we reduce the effect of domestic

sewage on the environment?

Copy and complete the diagram of acid rain

Acid Rain

Power station,

industry, houses, traffic

Sulphur dioxide, nitrogen oxides

SO2 and NOx react with water to form acid rain clouds containing

sulphuric acid and nitric acid.

Older trees die back

Acid rain in soil, surface run off

Acidification in

lakes, fish die

Learning outcomes 2

• State that organic waste is a food source for microorganisms.

• Explain the relationship between level of pollution with organic waste, numbers of micro-organisms, oxygen concentration and numbers of species.

• Describe the effect of increased numbers of microorganisms on the oxygen available to other organisms.

• Explain what is meant by “indicator species”.

Sewage

• Organic waste (sewage) provides food for bacteria, which allows them to grow and reproduce

• Bacteria use up the oxygen in the water.

• There is less oxygen for other organisms such as fish and insects.

• Animals such as fish, stonefly nymphs and shrimps decrease in number.

Domestic Pollution – sewageDescribe the trends shown in the graph below.

• As the concentration of sewage pollution rises, the population of bacteria rises.

• This is because the bacteria feed off the sewage which provides raw materials and energy for growth and reproduction.

• At the same time the concentration of oxygen falls.

• This is because the bacteria use up the oxygen as they break down the organic waste in the sewage.

• Animals such as fish and stonefly nymphs decrease in number.

Domestic Pollution – sewage

Mayfly nymphs cannot survive in waters low in oxygen.

They are an indication that the waters are clean

Pollution Indicators

• The presence or absence of particular organisms can indicate whether the water is polluted or not.

• These are called Indicator Species

Freshwater pollution

• Indicator Species– Animals found in water

with low levels of oxygen• Sludge worm• Rat-tailed maggot• Blood worm

– Animals found in water with high levels of oxygen

• Mayfly nymph• Stonefly nymph• shrimp

Air Pollution Indicators• Lichens

– Different types of lichen have different sensitivities to sulphur dioxide gas.

– 3 main types – crusty, leafy and shrubby

Indicator species present

Appearance of lichen

SO2 concentration

Crusty lichens only High

Crusty and leafy Medium

Shrubby low

Air Pollution Map

• Look at the air pollution map, and explain the distribution of the different types of lichen.

Quick Test1. What effect does domestic sewage have on the

number of bacteria in a river?2. How do the bacteria numbers affect the level of

dissolved oxygen in the water?3. How does the reduction in oxygen level affect the

numbers of fish and invertebrate numbers in the river?

4. What name is given to an organism whose presence or absence gives information about the level of pollution in a river?

5. Name two organisms that can live in water where the oxygen level is low.

6. Name two organisms that can only live in water that is unpolluted.

7. Which organisms are indicators of air pollution?

Learning Outcomes 3

• Explain an adverse effect of using fossil fuels and nuclear power as energy sources.

• Give 2 examples of poor management of natural resources and suggest possible improvements.

• Describe how the effect of poor management of natural resources can produce problems.

• Explain how components of an ecosystem are controlled in agriculture.

Alternative energy

• Alternative sources of energy need to be used to reduce the harmful effects of fossil fuels.

• Sources of energy include:-– Solar power– Wind power– Tidal power– Nuclear power

Solar Power

• Uses the suns energy to generate electricity.

• Advantages– No pollution

• Disadvantages– Initially expensive– Not useful in areas

with limited sunshine

Wind Power

• Uses movement energy from the wind to generate electricity.

• Advantages– Renewable– Low-level technology– No atmospheric pollution

• Disadvantages– Visual and noise pollution– Limited to windy sites– No wind, no energy

Tidal Power• Uses movement energy

of the tides to generate electricity.

• Advantages– Reliable– Low running costs– No air pollution– Renewable

• Disadvantages– Possible flooding– High initial costs– Obstacle to water

transport.

Nuclear Power

• Nuclear energy is an alternative to fossil fuels but it:– Produces radioactive waste, which can cause

cancer.– It is difficult to dispose of safely.

• Waste should be sealed in lead containers and dumped on the ocean beds.

Management of Resources

• Humans obtain resources from the Earth, this has led to the destruction of habitats.

• Resources are managed for:– Agriculture– Forestry– Fish stocks

• Conservation is important to prevent the loss of resources and wildlife.

Poor management of resources

• Overfishing in the North Sea

• Destruction of rainforests

• Overuse of land, leading to desert soils.

Solutions• Have fish quotas, or

increase net mesh to allow smaller fish to survive

• Produce food more efficiently to limit areas being logged for agriculture.

• Set aside areas as national parks.

• Use different agricultural practices, such as crop rotation and natural fertilisers.

Managing land for agriculture

• In agricultural practices it is necessary to control– Nutrient supply

• Addition of fertilisers – natural and artificial

– The habitat of the plant• Clearing land of competitors• Cultivation• Erects fences

Greenhouse Effect• The main greenhouse gases are carbon

dioxide and methane. These gases reduce the amount of heat radiated into space.

• Only a small rise in temperature may lead to climate changes and a rise in sea level.

What is the greenhouse effect?

Explain what is happening at points 1, 2 and 3 in the greenhouse.

What is the greenhouse effect?

The glass absorbs the infra-red radiation

Some of the energy is re-radiated into the greenhouse which makes it warmer

The soil becomes warm and radiates long wave infra-red rays.

The greenhouse effect

atmosphere

earth

The earth becomes warm and radiates long wavelength infrared rays

Greenhouse gases absorb some of the infra-red radiation. They radiate some of it back towards the Earth.

The atmosphere gets warmer

Effects of Global Warming

Deforestation• Deforestation reduces photosynthesis

which removes CO2, and also reduces the rate at which carbon dioxide is “locked up” as wood.

• Burning of chopped down wood or industrial uses, releases CO2.

• Increased microbe activity on the decaying material releases CO2 and methane (CH4)

Quick Test• Why do we need to reduce the amount of

fossil fuels burned for electricity?• Name two alternatives to fossil fuels as

sources of energy• Give one way of reducing the adverse effects

of fossil fuels.• Give one way of reducing the adverse effects

of nuclear power.• Give two possible solutions to the problem of

over fishing in the North Sea.• Which is the main gas responsible for the

greenhouse effect?

Carbon Dioxide Production• The pie chart shows the

percentage of increase in the carbon dioxide content of the atmosphere caused by various activities.– What percentage of the

increase in CO2 comes from generating electricity?

– Which human activity produces an increase in CO2 of 25%?

– Explain two ways in which deforestation causes an increase in the carbon dioxide concentration in the atmosphere.

Atmospheric Carbon Dioxide• The graph shows how

the amount of carbon dioxide in the atmosphere increased over 20 years.– What was the total

increase in the average CO2 concentration?

– Each year there is more CO2 in the air when it is winter in the northern half of the Earth. Explain this as fully as you can.