The carbon Cycle Flashcards
What is a Carbon store?
A place where carbon and its compounds may stay for a long period of time
What is a carbon sink?
A store that takes in more carbon than it releases
What is a carbon source?
A store that releases more carbon than it takes in
What is a carbon transfer?
Processes that transfer carbon between stores
What is a GtC?
A giga ton of carbon
1 gigatonne = 1 bn tonnes of carbon
What is anthropogenic CO2?
Carbon dioxide generated by human activity
What is a greenhouse gas?
Any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and holding heat in the atmosphere
What is the lithosphere?
the crust and uppermost mantle, the hard rigid outer layer of the earth
What is weathering?
The breakdown of rocks in situ by weather, plants and animals
What is the biosphere?
the total sum of all living matter
What is carbon sequestration?
The capture of CO2 from the atmosphere, or capturing anthropogenic CO2 from large scale stationary sources such as power stations - put into long term storage
Why is recycling carbon essential for life?
Enables food to be provided for plants and animals
A creation of energy sources
What can carbon form?
Biological molecules, gases (e.g CO2, CH4), Hydrocarbons
What is the primary source of carbon?
The Earth’s interior, is released at constructive and destructive boundaries
What are some of the stores in the carbon cycle? (6)
-sedimentary rock
- coal
- oil
- gas
- atmosphere
- phytoplankton
What are some of the transfers in the carbon cycle? (7)
-weathering and erosion
- rock cycle
- photosynthesis
- respiration
- burning
- decomposition
- diffusion
What is the largest store of carbon?
Marine sediments and sedimentary rock (lithospheric carbon)
99.9% of carbon
How is the ocean a store of carbon?
CO2 is absorbed directly from the air and river water discharges carbon in solutions
How is soil organic matter a store of carbon?
It contains rotting organic matter and are important carbon stores. Carbon can remain in the soils for hundreds of years
What are the inorganic sources of carbon in the lithosphere? (2)
- Fossil fuels e.g coal, oil, natural gas
- carbonate-based sedimentary deposits e.g limestone
What are organic sources of carbon within the lithosphere? (3)
-litter
-organic matter
-humid substances in soils
What are the 6 stores of carbon?
-marine sediments; sedimebtary rocks
-soil organic matter
-fossil fuel deposits
-atmosphere
-terrestrial plants
-oceans
How is carbon in the biosphere divided up?
Terrestrial and oceanic
What are the main sources of carbon in the biosphere? (5)
-Living vegetation
- Plant litter
- Soil hummus
- Peat
-Animals
Where is most of the carbon in the cryosphere?
In the soil areas of permafrost where decomposing plants and animals have frozen into the ground
What are methyl clathrates?
Molecules of methane frozen into ice crystals
What does most frozen organic matter in permafrost consist of?
Partially decayed roots, whole roots and other plant material
When is cryospheric carbon released into the atmosphere?
When the permafrost melts
What are oceanic carbon stores divided into? (3)
-Surface later (euphotic zone)
-Intermediate and deep layer
- Living organic matter
What is the euphotic zone?
The surface of the ocean where sunlight can penetrate and photosynthesis can take place
Why are sediments and rocks in the ocean so carbon rich?
Because when organisms die, they sink to the bottom of the ocean and decay, releasing carbon
What are fluxes?
Measurements of rate of flow of material between stores
What are processes?
Physical mechanisms which drive movement and fluxes
What type of system is the carbon cycle?
Closed
What is burial and compaction?
Organic matter is buried by sediments and becomes compacted
What is the geological component?
Where the carbon cycle interacts with the rock cycle in the processes of weathering, burial, subduction and volcanic eruptions
What is a sere?
A succession which relates to a specific environment
What is a lithosere?
Vegetation succession which occurs on bare rock
When was the Quaternary Period?
2.6 million years ago today
Cold rainwater can hold…
….more CO2
If rainwater hold more CO2, how is the rock affected?
It is weathered more
What is eccentricity?
The change in the shape of the Earth’s orbit around the sun
How does the eccentricity of the Earth’s orbit change?
in 100,000 year cycles. It change from a thin ellipses to a circle and back again
What is an insolation?
The amount of solar radiation that reaches the Earth’s surface
What does lower insolation mean for global temperatures?
They decrease
What natural factors can increase input of atmospheric CO2?
Periods of increased volcanicity
What human factors can increase input of atmospheric CO2? (3)
-Burning fossil fuels
-Causing more wildfires
-Climate change causing melting of tundra
What natural factors can reduce removal of CO2 from the atmosphere? (3)
-Glacial periods (less vegetation)
-Interglacial periods (warmer oceans, less CO2 absorbed)
-Winter in the northern hemisphere, hibernation
What human factors can reduce the removal of CO2 from the atmosphere? (2)
-Clearing vegetation from areas
- Climate change resulting in warmer oceans
What % of anthropogenic CO2 is from fossil fuel burning?
90%
24% absorbed by oceans
26% absorbed by plants
What are the human factors which can cause changes in the carbon cycle? (6)
-Combustion of fossil fuels
-Land use
-Farming practices
- Carbon sequestration in soils
-deforestation
-urbanisation
How does deforestation affect the carbon cycle? (4)
- Above ground biomass is burned, releasing CO2
- Forest clearing may accelerate decay of dead wood, litter or below ground organic carbon
- in a natural system, trees would decay very slowly
- upsets equilibrium of carbon in the forest
How can deforestation impact soils?
Without shade from trees, they dry out
How does urbanisation affect the carbon cycle? (2)
-replacing open countryside with concrete and tarmac replaces important stores
-urban areas produce far more CO2 than rural ones
What does terrestrial/ biological sequestration involve?
The use of plants to capture CO2 from the atmosphere and store it in stems and roots
What is the carbon budget?
Uses data to describe the amount of carbon that is stored and transferred within the carbon cycle
What is the enhanced greenhouse effect?
The impact on the climate from the additional heat retained due to increased CO2
What is geo-sequestration?
Technology capturing greenhouse gas emissions from power stations and pumping them into underground reservoirs
What is radiative forcing?
The difference between the incoming solar energy absorbed by the earth and energy radiated back to space
What is soil organic carbon (SOC)?
The organic constituents of the soil, tissues from dead plants/animals, products of decomposition, microbial biomass etc
How does the carbon budget affect the ocean?
Excess carbon in the ocean makes the water more acidic, putting marine life in danger.
How does the carbon budget affect the atmosphere + land?
Excess carbon in the atmosphere warms the planet and helps plants on land grow more
How does the carbon budget affect the global climate?
Exceeding this threshold could cause global temperatures to reach dangerous levels.
How much carbon is stored in the ocean?
38,000 GtC
How much carbon is stored in the Lithosphere? - give 4 sources
100,000 GtC - 99.9%
Sedimentary rock (e.g limestone)
Organic carbon
Hydrocarbons such as fossil fuels
Marine sediments
How much carbon is stored in the hydrosphere? - give 3 sources
0.0076%
Carbonate ions
Bicarbonate ions
Dissolved CO2
How much carbon is stored in the pedosphere? - give 2 sources
1500 GtC
0.0031%
Soil organisms
Plant remains
How much carbon is stored in the Cryosphere? - give 2 sources
0.01%
Permafrost
Methyl clathrates
How much carbon is stored in the Atmosphere? - give a source
750 GtC
0.0015%
Gaseous carbon
How much carbon is stored in the biosphere? - give a source
560 GtC
0.0012%
Living plants and animals
How do farming practices affect carbon emissions?
- Soil ploughing inverts the layers, mixing in air and increasing the soil microbial activity
- Soil in organic matter broken down more quickly
- Carbon lost from the soil into the atmosphere, increasing atmospheric carbon levels
- Enteric fermentation accounted for 39% of the sector’s total GHG outputs in 2011
- Rice paddy fields accounted for 10%
How has land use change affected emissions?
- Over ½ worlds population lives in urban areas
- Urban population expected to reach 60% of what it is currently by 2030
- Increased emissions from transport and domestic use and manufacturing
- In 2012, cities responsible for 47% global carbon emissions
- NA highest carbon emissions, in 2012 15.6 tonnes of CO2
How do processes such as burial, compaction, and decomposition create different hydrocarbons?
- Dead plants or animals turn into fossil fuels following burials
- Pressure from multiple layers of sediment leads to an anoxic environment for decomposition without oxygen
- Carbon in sugar molecules rearranged to form other compounds
Dynamic equilibrium
Inputs and outputs are balanced over a long time period achieved in numerous ways
How much carbon is stored in fossil fuels?
4000 GtC
