✅3.1.1.3 - The Carbon Cycle Flashcards
What is a Carbon store?
The lithosphere, hydrosphere, cryosphere, atmosphere etc
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 gigatonne of Carbon, 1 gigatonne = 1 billion tonnes
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, therefore 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?
It enables food to be provided for plants and animals and creation of energy sources
What can carbon form?
Biological molecules, Gases (eg CO2, CH4), Hydrocarbons
What is the primary source of Carbon?
The Earth’s interior
What are some of the stores in the carbon cycle?
Sedimentary rock, coal, oil, gas, plants, atmosphere, phytoplankton etc
What are some of the transfers in the carbon cycle?
Weathering and erosion, rock cycle, photosynthesis, respiration, burning, decomposition, diffusion
What is the largest store of carbon?
Marine sediments and sedimentary rock
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?
They contain rotting organic matter and are important carbon stores. Carbon can remain in the soils for hundreds of years
What are inorganic sources of carbon in the lithosphere?
Fossil fuels, eg coal, oil, natural gas and carbonate-based sedimentary deposits
What are organic sources of carbon within the lithosphere?
Litter, organic matter and humic substances in soils
What are the three stores of carbon in the lithosphere?
Marine sediments & sedimentary rocks
Soil organic matter
Fossil fuel deposits
How is carbon in the biosphere divided up?
Into terrestrial and oceanic
What are the main sources of carbon in the biosphere?
Living vegetation Plant litter Soil humus 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?
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 fuxes
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 to 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 changes from a thin ellipse to a circle and back again
What is 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?
Burning fossil fuels
Causing more wildfires
Climate change causing melting of tundra
What natural factors can reduce removal of CO2 from the atmosphere
Glacial periods (less vegetation) Interglacial periods (warmer oceans, less CO2 absorebd) Winter in the northern hemisphere, hibernation
What human factors can reduce the removal of CO2 from the atmosphere
Clearing vegetation from from areas
Climate change resulting in warmer oceans
What percentage of anthropogenic CO2 is from fossil fuel burning?
90%
How does ploughing increase CO2 emissions?
It aerates soil, increasing microbial activity and therefore decomposition, more CO2 released
What are the human factors which can cause changes in the carbon cycle?
Combustion of fossil fuels Land use Farming practices Carbon sequestration in soils Deforestation Urbanisation
How does deforestation affect the carbon cycle?
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 the balance of carbon in the forest
How can deforestation impact soils?
Without shade from trees, they dry out
How does urbanisation affect the water cycle?
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 is the carbon budget affecting ocean salinity?
Decrease in salinity in the deep North Atlantic, more freshwater being added to the ocean. Slowing down of large scale oceanic circulation
