4.10- 4.15 carbon cycle, environment

What are the stages of the carbon cycle

Respiration, photosynthesis, decomposition, combustion

Explain respiration

Plants and animals aerobically respire which releases CO2 into the air, decomposers also respire while they break down compounds

Explain photosynthesis

Plants remove CO2 from the air through photosynthesis

Explain decomposition

Dead plants and animals are broken down by decomposers, the carbon is returned into the atmosphere

Explain combustion

When plants and fossil fuels (remains of dead animals) are burnt and the barb on dioxide is released into the atmosphere

How is Sulfur dioxide released?

When fossil fuels are burnt

What are the consequences of sulfur dioxide pollution and how does it happen?

It dissolves in water droplets in clouds to form dilute sulfuric acid - making acid rain

Acid rain makes rivers too acidic leading to aquatic organism dying, corrodes metals and limestone buildings, leeches minerals out of soil so plants and trees cannot survive

How is carbon monoxide released?

It is released when fossil fuels are burnt through incomplete combustion

Effects of the release of carbon monoxide

• binds irreversibly tot he haemoglobin, reducing the oxygen carrying capacity of red blood cells

  • Causing tiredness, unconscious, death, affect growth of foetus in pregnant women

What are green houses gases and how does it cause global warming?

Gases that absorb infrared radiation from the Sun, trapping it above the earths surface (greenhouse effect) which leases the the increase of the earth’s temperature (global warming)

What are the different greenhouse gases and their sources

Water vapour- rivers, lakes

Carbon dioxide - deforestation, fossil fuels

Nitrous oxide - fertilisers, engines of vehicles

Methane - cattle

CFC - refrigerators, aerosol sprays

What are the effects of global warming

• climate change

• Water levels rising as glaciers melt

• Loss of habitats

• Uninhabitable environments - some species will become extinct or they will migrate

How is water polluted by sewage?

• sewage is rich in minerals/nutrients which allow decomposers and algae to thrive

• Decomposers and bacteria respire aerobically to break down sewage, using oxygen

• Algae bloom stops light from reaching aquatic plants, causing them to die

• These lead to oxygen depletion, causing aquatic organisms to die

What is eutrophication?

When fertilisers are washed off from the land into nearby rivers and lakes by the rain

What is the effect of eutrophication?

The excess nutrients that are washed into lakes makes algae rapidly grow, blocking sunlight causing the plants below not being able to photosynthesise leading to oxygen deprivation and die