The Carbon Cycle Flashcards
What is the Carbon Cycle?
The carbon cycle describes the process in which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere.
How much carbon is found in each of earth’s systems?
Lithosphere:
>Over 99.9% of carbon on earth is stored In sedimentary rocks (limestone).
>About 0.004% of carbon is stored in fossil fuels, such as coal and oil.
Atmosphere:
>The atmosphere contains about 0.001% of the Earth’s carbon.
>Carbon is stored as carbon dioxide in the atmosphere.
Biosphere:
>The biosphere contains approximately 0.004% of Earth’s carbon.
>Carbon is stored in the tissues of living organisms. Transferred to the soil when organisms die and decay.
Cryosphere:
>The cryosphere contains less than 0.01% of Earth’s carbon.
> Most carbon in the cryosphere is found in the soil in areas of permafrost (permanently frozen ground) where decomposing plants and animals have frozen into the ground.
Hydrosphere:
>The hydrosphere contains around 0.04% of Earth’s carbon.
>Carbon dioxide is dissolved into rivers, lakes and oceans ( found in deep areas)
>A small amount is found at the ocean surface where it is exchanged with the atmosphere.
How does photosynthesis transfer carbon? quick
Photosynthesis:
>This transfers carbon from the atmosphere to biomass.
>Plants use energy from the sun to change carbon dioxide and water into glucose and oxygen. This enables plants to grow.
>Carbon is passed through the food chain and released through respiration and decomposition.
How does respiration transfer carbon? quick
Respiration:
>Respiration transfers carbon from living organisms to the atmosphere.
> Plants and animals break down glucose for energy, releasing carbon dioxide and methane In the process.
How does combustion transfer carbon? quick
Combustion:
>Combustion transfers carbon stored in living, dead or decomposed biomass to the atmosphere by burning.
>Wildfires cause carbon flows.
How does decomposition transfer carbon? quick
Decomposition:
>Decomposition transfers carbon from dead biomass to the atmosphere and the soil.
>After death, bacteria and fungi break organisms down. CO2 and methane are released.
How do ocean uptake and loss transfer carbon?
Ocean uptake and loss:
>Co2 is directly dissolved from the atmosphere into the ocean. It is also transferred to the oceans when it is taken up by organisms that live in them e.g. plankton.
> Carbon is also transferred from the ocean to the atmosphere when carbon-rich water from deep in the oceans rises to the surface and releases CO2.
How does weathering transfer carbon?
Weathering:
>Chemical weathering transfers carbon from the atmosphere to the hydrosphere and biosphere.
> Atmospheric carbon reacts with water vapour to form acid rain. When the acid rain falls on rocks, it dissolves them. The molecules from the reaction may be washed into the sea and create co2.
How does sequestration (capturing and storing atmospheric carbon dioxide)
transfer carbon? Slow
Sequestration:
>Carbon from the atmosphere can be sequestrated in sedimentary rocks or as fossil fuels. Rocks and fossil fuels form over years when dead animals and plant material in the ocean falls to the floor and is compacted.
>Carbon in fossil fuels is sequestrated until we burn them.
What natural processes can change the carbon cycle?
Wildfires:
> Wildfires rapidly transfer large quantities of carbon from biomass to the atmosphere. Loss of vegetation decreases photosynthesis, so less carbon is removed from the atmosphere.
>In the longer term, fires can encourage the growth on new plants, which take in co2 from the atmosphere for photosynthesis.
Volcanic activity:
>Carbon stored within the Earth in magma is released during volcanic eruptions. The majority enters the atmosphere as co2
>Recent volcanic eruptions seem to let out less co2 as human activities, however, there is potential for a large eruption to occur.
What human impacts can change the carbon cycle?
Deforestation:
>Forests may be cleared for agriculture, logging, or to make way for developments.
>Clareance reduces the size of carbon stores, if the cleared forest is burned, there will be a rapid flow of carbon from the biosphere to the atmosphere.
Farming practices:
>Animals release carbon and methane when they respire and digest food.
>Ploughing can release co2 stored in soil.
>Growing rice in rice paddies release a lot of co2.
Land use changes:
>Vegetation is removed to make way for buildings- this reduces carbon storage in the biosphere.
>Concrete production releases co2 and lots of concrete is used when urban areas expand.
Hydrocarbon (fossil fuel) extraction and use:
>Extracting and burning fossil fuels releases co2 into the atmosphere.
>Without human intervention, the carbon would remain sequestrated in the lithosphere for millions of years.
What is the carbon budget?
The carbon budget is the difference between the inputs of carbon into the subsystem and the outputs of carbon from it.
For example: In the atmosphere, inputs of carbon come from volcanic eruptions, burning fossil fuels, respiration, and ocean loss, and outputs occur through photosynthesis, sequestration, decomposition, chemical weathering and ocean uptake.
How does the change in the carbon cycle have an impact on the atmosphere and climate?
> The carbon cycle affects the number of gases containing carbon. These are greenhouse gases- they trap some of the sun’s energy, keeping the planet warm.
> As the number of greenhouse gases in the atmosphere increase ( due to deforestation) temperatures are expected to rise. This is global warming.
> Changes in the temperature across the globe will affect other aspects of the climate, e.g. more intense storms are predicted.
How does the change in the carbon cycle have an impact on the land?
> The carbon cycle allows plants to grow- if there was no carbon in the atmosphere, then plants would not be able to photosynthesize.
> Changes in the carbon cycle can reduce the amount of carbon stored in the land, e.g. warmer temperatures caused by global warming are causing permafrost to melt.
> An increase in global temperatures, also increase the chances of wildfires.
How does the change in the carbon cycle have an impact on the oceans?
> As part of the carbon cycle, carbon dioxide is dissolved directly into oceans from the atmosphere.
> Increased levels of co2 in the atmosphere can increase the acidity of the oceans as they absorb co2. This can have negative effects on marine life.
> Global warming can also affect oceans. For example, organisms that are sensitive to temperature, e.g. phytoplankton, may not be able to survive at high temperatures, so their numbers decrease. This means that less co2 is used by them for photosynthesis, so less carbon is removed from the atmosphere.
> Warmer water is less able to absorb co2, so as temperatures rise the amount of co2 that could potentially dissolve in the sea will decrease.
