The Carbon Cycle

Learning outcomes Describe the cycle of carbon through the ecosystem Describe how humans have affected the carbon cycle

True or false? All living things contain carbon in the form of compounds? TRUE

Carbon Essential element found in all living things Used to make important molecules such as proteins, carbohydrates, fats and nucleic acids

Biotic forms of carbon - From the air to living things CO 2 makes up 0.036% of the atmosphere CO 2 in the air is the source of all carbon compounds in living things Photosynthesis is the process by which CO 2 in the air is changed to carbon in living things by plants on land and algae in the sea

Abiotic forms of carbon 1.Carbon compounds dissolved in the oceans (e.g. Carbonate, bicarbonate) 2.Fossil fuels – coal, oil and natural gases 3.Limestone

Carbon in the ocean 36, 000 gigatonnes (10 9 ) Mostly in the form of the bicarbonate ion (HCO 3 - ) Helps control the pH of the ocean Bicarbonate combines with calcium to form limestone (CaCO 3 )

Returning carbon back to the atmosphere 1. Respiration – Plants and animals give out CO 2 during this process Glucose + Oxygen CO 2 + Water + Energy 2. Combustion – Burning of fuel such as oil, natural gas, coal and wood in a plentiful supply of oxygen all produce CO 2

Returning carbon back to the atmosphere 3. Decomposers – Bacteria and fungi feeding on dead animals and plants release CO 2

Activity – Carbon Cycle Diagram Get into groups of 3 or 4 Using the notes you have taken, come up with a Carbon cycle diagram It is to be done on an A3 sheet It must include The abiotic and biotic sources of carbon Atmospheric carbon Decomposers Arrows showing how they are linked and by what processes Simple pictures

Creating the class Carbon Cycle

How humans affect the cycle Human activity has affected the balance of the carbon cycle by Think, pair share  Burning down forests – reduces CO 2 absorption by photosynthesis, increases CO 2 formation by combustion  Burning fossil fuels