4.9- Carbon Cycle

                                            
1) Photosynthesis:

• CO2+H20------>C6H12O6
• reduces carbon dioxide in the atmosphere

2) Feeding:

• Carbon passes along the food chain

3) Respiration:

• Aerobic: C6H12O6 + O2----->CO2+H20+ Energy
• Adds CO2 to the atmosphere
• All organisms are giving off carbon dioxide to the atmosphere through respiration 

4)Decomposition: 

• Organic molecules are broken down by the decomposer organisms which includes bacteria and Fungi
• This will result in the release of carbon dioxide back to the atmosphere

5) Combustion:

• Fossil fuels (Oils and coals)------------> Carbon dioxide 
• Industrial uses can contribute the amount of carbon dioxide in the motor vehicles
• Combustion can occur naturally ( forest fires)

4.14- Enhanced Greenhouse effect

Understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to global warming and its consequences

• Pollution of carbon dioxide, methane and water vapour (greenhouse gases)
• If their concentration increases then the Infra-red light would be increasingly re-emitted rather than escaping into space
• This will raise the average global temperature which is called global warming
• Consequences:
• Raised sea levels- melting of icecaps
• Changing ocean and wind currents
• This leads to climate change

This will lead to the worlds Biome distribution changing, polarised caps melting, etc.

4.13- Greenhouse gases

Human activities effecting greenhouse gases:

• Burning of fossil fuels results in the formation of carbon dioxides and nitrous dioxides which are greenhouse gases.
• Cows emit methane gas which is about 9% of the atmospheric gases.
• Evaporation of water to form water vapour, clouds are a significant contributor
• Refrigeration/ Solvents are associated with the absorption of UV light and catalysing the breakdown of the ozone layer

4.12- Greenhouse Effect

a) represents UV light from the sun (short wavelength, high energy)
b) shows that 50% is reflected back mainly by the clouds
c) shows absorption on the surface where the UV light is converted and emmited as Infra-red
d) shows the Infra-red (longer wavelength) being emitted back out
e) shows heat which is lost to space
f) represents some of the greenhouse gases like water vapour, CO2, CH4
g) Infra-red light absorbs the greenhouse gas and then re-emits and re-distributes it with some of the gases going back to the surface

The hypothesis of the enhanced greenhouse effect is that if we emit more CO2 and CH4, they will absorb more of the escaping Infra-red radiation and emit it back to earth, raising the temperature higher and causing climate change
CFC are well known for their effect on the ozone layer O3
CL- catalyses the breakdown of O3 to O2. O3 is better than absorbing light than O2 so we are basically removing the protection of the ozone layer.

4.11- Gas Pollution

• Sulphur dioxide:
• Is added to the atmosphere when the fossil fuels are combusted and also with the combustion of petrol in vehicles
• In the atmosphere, Sulphur dioxide combines with water vapour and forms Sulphuric acid which is also known as acid rain
• Effects on plants and animals:
• They are often burned by the sulphuric acid
• Magnesium and Calcium ions are leached out of the soil which means that the plants can't obtain them from the soil
• Lakes have reduced pH which causes release of Aluminium ions and this effects fish as the Aluminium causes the thickening of the mucus that lines the gills and reduces the fish's ability to take in oxygen. This kills the fish as it suffocates
• Carbon Monoxide:
• Produced when fossil fuels such as coal/gas are burned with insufficient oxygen
• Combines with Haemoglobin in red blood cells and forms Carbaminohaemoglobin which blocks the Haemoglobin from carrying oxygen which reduces oxygen circulation in the body