4.9 - Carbon Cycle

- 1. Photosynthesis - CO2 + H20 ----Photosynthesis (Chlorophyll)----> Glucose + O2
    - CO2 comes from the atmosphere = 0.03%
    - Reduces the atmospheric CO2 


- 2. Feeding - Producer ---> primary consumer (takes carbon from the producer and grows)  ---> secondary consumer
    - All respire sending out CO2 into the atmosphere 


- 3. Respiration - Glucose + O2 ---enzymes in the cell---> energy + CO2 + H2O 
    - Adds CO2 to the atmosphere 


- 4. Decomposition - death of organic molecules ----bacteria, fungi----> CO2 


- 5. Combustion - fossil fuels - Compression and pressure of animals and plants. Results in oils and coals -----combustion---> CO2
    - Industrial and vehicles combust fuel for their movement 
    - natural combustion - Lightning striking vegetation = forest fries, grassland fires

4.14 - Enhanced Greenhouse effect

- Greenhouse effect caused by pollution - CO2, CH4, Water Vapour  (greenhouse gases) 
- The gases increase their concentration in the upper atmosphere 
- leads to the infrared light from the planet being increasingly reemitted back down towards the earths surface rather then escaping into space. 
- This raises the average global temperature = global warming. 


Consequences: 
- Melting of ice capes in the polar regions resulting in more water in the oceans so..
- Raised sea levels this would then change the.. 
- Ocean currents 
- Change the way wind is generated 
- All lead to the larger Picture = Climate Change. 
- Result in the change of the distribution of the worlds biomes 

4.13 - Greenhouse Gases

- Burning of fossil fuels releases CO2, NO2 and SO2. 
- CO2 and NO2 are Green house gases. 
- SO2 absorbs infrared 
- released from factories and vehicles (industrial) and burning of coals (domestic) 


- Farming - cows emit methane gas (CH4) - about 90% of the atmospheric gas. Huge amount


- Evaporation of water - forms water vapour  - clouds significant contributor to the greenhouse effect. 


- Refrigeration/ Solvents - CFCs - Carbon, Fluorine and Chlorine - absorption of UV light and catalytic break down 

4.12 - Greenhouse Effect

- a) UV light from the sun - sort wave length or high energy 
- b) 50% of this light is reflected back into space (plants reflect)
- c) absorption on the surface - UV --> infrared 
- d) infrared light - long waves 
- e) lost to space as heat 
- f) greenhouse gases (water vapour, CO2, methane) 
- g) infrared light hits the GHG and absorb the energy then reemits it in all directions, including downwards 
     - The ones that go down towards the surface are what cause the temperature to rise. 


Enhanced greenhouse effect 
if you raise the levels of GHG they will absorb more of the escaping infrared radiation and emit it backwards towards the earth. - High temperatures so climate change. 


CFCs - ozone layer 
           - Carbon, Florine, Chlorine
Cl3F ---sunlight---> CCl2F- +Cl-      = this breaks down O3 into O2. 
- O3 is much better at absorbing UV light


 - depletion of the ozone layer 

4.11 - Gas Pollution

Sulphur Dioxide 
- SO2 - as a gas is added to the atmosphere. 
- Added by combustion of fossil fuels -  in factories - burning of fossil fuels (coals, oils) - gases given off = SO2.
- Added from combustion in vehicles - combustion of oils and gases for petrol = SO2
- In the atmosphere - SO2 + H2O ---> Sulphuric Acid. 
Sulphuric Acid is found in clouds so when it rains it is acid rain. 
- Acid rain effects plants and animals. = 
- Trees become 'burned' on the surface from the acid. 
- The root system is effected - acid rain causes calcium and magnesium ions to be leached (means the plant can't obtain calcium or magnesium so it suffers from clorosis (yellowing of the leaves) so it can no longer grow) 
- Acid rain - forms streams - form into the lakes. 
- In lakes the acid rain reduces the pH - releases Aluminium ions which affects the fish. 
- The aluminium is what thickens the mucus of the gills on the fish and reduces the fishes ability to take O2 from the water - suffocates, dies. 


Carbon Monoxide 
- CO as a gas
- Produced when fossil fuels (coal, gas) are burned with insufficient O2
- Combines with the hemoglobin in the red blood cells and forms carbomino hemoglobin 
- Blocks hemoglobin from carrying oxygen around the body 
- Reducing the oxygen circulation 
- Toxic 
- Too much carbon monoxide can me fatal, death