2.2 – The Carbon Cycle

Where is Carbon Stored? Short Term Stores: Land and marine animals and plants and in decaying organic matter. Land and marine animals and plants and in decaying organic matter. Atmosphere as CO 2 and in the upper layer of the ocean in its dissolved form. Atmosphere as CO 2 and in the upper layer of the ocean in its dissolved form. Long Term Stores: In water: Intermediate and deep depths of the ocean as dissolved CO ₂ In water: Intermediate and deep depths of the ocean as dissolved CO ₂ On land: coal, oil gas deposits (fossil fuels) dead plants and animals On land: coal, oil gas deposits (fossil fuels) dead plants and animals Largest stores are found in SEDIMENTARY ROCK (eg: limestone) and marine sediments Largest stores are found in SEDIMENTARY ROCK (eg: limestone) and marine sediments

Sedimentation Decaying matter and soil particles begin to form layers, eventually becoming rock Carbonate Carbon/oxygen organisms containing calcium carbonate Becomes limestone

How is Carbon Cycled Through the Ecosystems? 1. Photosynthesis 2. Respiration 3. Decomposition 4. Ocean Processes 5. Volcanic eruptions and large scale forest fires

1. Photosynthesis Chemical process that cycles both C and O 2 through ecosystems  Coverts solar energy into chemical energy CO 2 in the atmosphere enters the leaves of plants and reacts with water in the presence of sunlight to produce carbohydrates (glucose) and O 2 : Consumers eat producers and obtain energy from them in the form of carbohydrates Some micro-organisms such as cyanobacteria use photosynthesis, not just green plants for energy!

2. Cellular Respiration Process where animals and plants (in the absence of light) release CO ₂ into the atmosphere by converting O 2 and glucose (C 6 H 12 O 6 ) into CO ₂ and water: C 6 H 12 O O 2  6CO H 2 O + energy C 6 H 12 O O 2  6CO H 2 O + energy

3. Decomposition The breaking down of dead organic matter The breaking down of dead organic matter Decomposers include: bacteria, fungi, insects, worms (aka Detrivores). Decomposers include: bacteria, fungi, insects, worms (aka Detrivores). They breakdown cellulose (plant matter) and in the process convert it into CO 2 They breakdown cellulose (plant matter) and in the process convert it into CO 2

4. Ocean Processes Ocean currents and colder oceans found at high latitudes cause more carbon to be retained as it sinks deeper into the depths of the ocean. Ocean currents and colder oceans found at high latitudes cause more carbon to be retained as it sinks deeper into the depths of the ocean. These deeper carbon rich currents move slowly to the tropics where it gradually is warmed and is released back into the tropical atmosphere: These deeper carbon rich currents move slowly to the tropics where it gradually is warmed and is released back into the tropical atmosphere:

Carbon in the Ocean

5. Volcanic Eruptions and Forest Fires Carbon dioxide is released from volcanoes due to the melting of sedimentary rock, a rich store of carbon into the atmosphere Carbon dioxide is released from volcanoes due to the melting of sedimentary rock, a rich store of carbon into the atmosphere Forest fires due to the rapid burning of trees releases carbon dioxide into the atmosphere. Forest fires due to the rapid burning of trees releases carbon dioxide into the atmosphere.

6. Human Activities Activities such as: industry, motorized transportation, land clearing, agriculture, urban expansion Activities such as: industry, motorized transportation, land clearing, agriculture, urban expansion Have a negative impact on the carbon cycle Have a negative impact on the carbon cycle Since 1850 (industrial revolution) carbon dioxide gas in the atmosphere has increased by 30% Since 1850 (industrial revolution) carbon dioxide gas in the atmosphere has increased by 30% We are producing more carbon than the natural carbon cycle can store it. We are producing more carbon than the natural carbon cycle can store it.