The Carbon Cycle Flashcards
Where is carbon found on Earth?
LITHOSPHERE
Over 99.9% of carbon is stored in sedimentary rocks such as limestone.
About 0.004% of carbon is stored in fossil fuels.
HYDROSPHERE
Around 0.04% of the Earths carbon is stored in the ocean.
ATMOSPHERE
The atmosphere contains about 0.001% of the earths carbon.
BIOSPHERE
Carbon is stored in the tissue of living organisms, it’s transferred into soil when they die.
CRYOSPHERE
Carbon is stored in soil and dead animals found in permafrost.
What are the Carbon Flows?
Photosynthesis - Transfers Carbon in the atmosphere into biomass, plants use solar energy to change carbon dioxide into glucose and oxygen which enables plants to grow.
Carbon is passed through the food chain and released through respiration and decomposition.
Respiration - Transfers Carbon from living things into the atmosphere.
Combustion - Combustion such as wildfires transfers carbon stored in living things into the atmosphere.
Decomposition - Bacteria breaks down organisms and C02 is released in the process.
Ocean uptake and loss - C02 is dissolved by the oceans and can be released when carbon rich water from deep in the ocean rises.
Weathering - Acid rain may dissolve rocks cratering calcium carbonate which is then washed into the sea which small sea creatures can use to make shells.
Sequestration - Carbon can be held in sedimentary rocks or as fossil fuels where dead animal material is compacted over millions of years.
How can natural processes change the carbon cycle?
Wildfires - Rapidly transfer large quantities of carbon from biomass to the atmosphere, loss of vegetation also decreases photosynthesis so less carbon is removed from the atmosphere.
However in the long term wildfires can encourage growth which takes in carbon, therefore wildfires could be seen as having a neutral effect.
Volcanic activity - Carbon is stored in the earth and is released during eruptions adding C02 to the atmosphere.
Recent volcanic eruptions have released much less C02 than human actions however there is the potential for a large eruption to disrupt the carbon cycle significantly.
How can Human processes change the Carbon Cycle?
Since the Industrial revolution we’ve caused the flow from the lithosphere to the atmosphere to grow exponentially.
Fossil Fuel extraction and use -
Without human intervention this carbon would have remained sequestered for millions of years to come but our combustion has lead to huge flows into the atmosphere.
Deforestation -
Forest clearance reduces the size of carbon store and if it is burned there is a rapid flow of carbon from the biosphere to the atmosphere.
Farming practices -
Animals including cattle release C02 and methane when they respire and digest. Ploughing can release C02 stored in soil, mechanisation also is increasing C02.
Land use changes -
Vegetation is removed to build etc. so reduces carbon stores.
What are some of the impacts of global warming on the Atmosphere, Land and Oceans?
ATMOSPHERE - Increased Carbon in the atmosphere are acting like greenhouse gasses, they trap the suns energy and keep the planet warm.
As the concentration increases global temperatures are increasing.
LAND - Changes in temperatures can melt permafrost releasing carbon and an increase in temperatures could increase the frequency of wildfires.
OCEANS - CO2, which can be dissolved directly into the sea is used by organisms such as Phytoplankton for photosynthesis and by others to form shells. Increasing C02 in the atmosphere may also increase the acidity of the oceans which could have adverse effects on marine life. Global warming may warm waters so much that photosynthesises underwater vegetation may die reducing carbon stores.
Warmer water also holds less C02.
