Lesson 7- What is the carbon cycle and where is carbon stored? Flashcards
Different types of carbon
- Carbon dioxide(CO₂)is a gas found inoceans, soils and the atmosphere andas a waste product in respiration(animal and human)
- Methane(CH₄)is a greenhouse gasfound in rocks, oceans, permafrost,soils, etc.
- Hydrocarbons(fossil fuels)found insedimentary rocks in gas, liquid, or solidform
- Calcium carbonate commonsubstance found in limestone rock,shells, eggs, etc.
- Carbon biomoleculesare
organicmolecules including carbohydrates, fats,proteins etc., and form 50% of the totaldry mass of living things
What is the carbon cycle?
- The Earth’s carbon pools include the atmosphere, soils, oceans, and crust, each storing significant amounts of carbon.
- Fluxes, such as photosynthesis, respiration, decomposition, and combustion, move carbon between these pools.
- Through photosynthesis, carbon from the atmosphere is used by plants to grow, which later returns to the atmosphere via respiration, decomposition, or combustion.
- This continuous cycle maintains the crucial balance of carbon in ecosystems.
What are the two types of carbon cycles?
- Local carbon cycle and Global carbon cycle
-Slow carbon cycle and fast carbon cycle
Types of carbon cycle- Local carbon cycle
- The carbon cycle on a local scale is in a specific area.
- For example within a rainforest the carbon cycle is an open system because carbon can enter and leave the system.
-This can be through deforestation or burning transferring carbon out of the system into the atmosphere.
Types of carbon cycle- Global carbon cycle
- The global carbon system can be subdivided into systems operating on land, oceans and atmosphere.
- On a global scale the carbon cycle is a closed system because only energy from the sun can cross into the cycle.
- No new carbon enters or leaves
Types of carbon cycle- Slow carbon cycle
- Long-term or slowcarbon cycle: The movement of carbon between the atmospheric, oceanic and lithospheric stores
- The atmosphere, oceans and land are linked together transferring carbon in a giant slow-moving systemwhich takes between100 and 200 million yearsfor carbon to flow through it
Types of carbon cycle- Fast carbon cycle
- Short-term or fastcarbon cycle: The movement of carbon from living things to the atmosphere and oceans
- The short-term orfast cycle through the biosphere moves up to a thousand times more carbonin a shorter space of time
How is carbon distributed globally?
- The main stores of carbon are located in, and transferred between the biosphere (plants), lithosphere (rocks), pedosphere (soils), cryosphere (ice), atmosphere (air) and hydrosphere (water).
What is a sink and a source?
- Sink = taking in more carbon than giving out.
- Source = giving out more carbon than taking in
Over time some sources can turn into sinks and some sinks can turn into sources.
Stores of carbon
- Biosphere- plants animals
- Lithosphere- ground
- Pedosphere- soil
- Cryosphere- ice
- Atmosphere-air
- Hydrosphere-water
Stores of carbon-Biosphere
- 0.0012% of all carbon
-Residence Time of 18 years
Stores of carbon- Lithosphere
- 99.98% of all carbon
-Sedimentary rocks like limestone (Calcium carbonate)
-Residence time of 240-300 million years
Stores of carbon- Pedosphere
- 0.0031% of all carbon
- Stores 300 billion tonnes of carbon as organic matter Peat soils containing the most
-Residence time of days to 1000’s of years
Stores of carbon- Cryosphere
-0.0018% of all carbon
- Permafrost of tundra contains plant material
-Residence time of 1000s of years
Stores of carbon- Atmosphere
- 0.0015% of all carbon
- Mainly as Carbon Dioxide and Methane (CO4)
-Residence time of 6 years
Stores of carbon- Hydrosphere
- 0.0076% of all carbon
- 90% of oceanic carbon is dissolved as bicarbonate with carbonate ions and dissolved C02
-Residence time of 25 years for surface of ocean but deep ocean carbon can be 1250 years
How are the stores of carbon changing over time?
1) Global distribution of vegetation and ecosystems
2) Global distribution of land masses
3)Seasonal changes in plants
4) Human caused seasonal changes
Stores of carbon changing-Global distribution of vegetation and ecosystems
- Changes the amount of stored carbon - the Arctic and the Sahara Desert have virtually no plant storage, whereas the Amazon rainforest has all-year-round storage, Equally, tropical trees will store more carbon than a small bramble (change over space).
Stores of carbon changing- Global distribution of land masses
- Carbon uptake is higher in the middle/high latitudes of the northern hemisphere but less in the southern hemisphere (less land mass) (change over space).
Stores of carbon- Seasonal Changes in plants
- There is a seasonal change in the amount of carbon in the terrestrial (land) biosphere because plants grow and decay differently during the summer compared to the winter (change over time).
Stores of carbon- Human caused seasonal changes
- CO2 emissions change with the seasons we use more fossil fuels in winter in the northern hemisphere than in the summer, equally in winter there are less plants to absorb CO2 (change over time).
How does carbon move from one store to another?
1) Photosynthesis by the tree which removes CO2 directly from the atmosphere
2) Respiration by the tree and microbes in the soil, returns carbon to the atmosphere as CO2
3) Decomposition of leaf litter or death of the tree, also returns carbon to the atmosphere or soil
4) Combustion due to wildfires releasing large amounts of stored carbon in the tree
What is a sere?
A ‘sere’ is a stage in the succession of vegetation in an ecosystem
- When environmental equilibrium or balance is reached further succession stops the final stage of a sere is reached
Types of sere
- A lithosere is vegetation succession that occurs on bare rock
- A hydrosere occurs in freshwater e.g. a pond
- A halosere occurs in salt-rich conditions e.g. salt marshes
- A psammosere occurs in sandy areas e.g. sand dunes