Carbon Flashcards
What is the carbon cycle?
The biogeochemical cycle by which carbon moves from one sphere to another. It acts as a closed system made up of linked subsystems that have input, throughputs and outputs.
What stores is carbon present in?
▪ The atmosphere as CO2 and methane
▪ The hydrosphere as dissolved CO2
▪ The lithosphere as carbonates in limestone and fossil fuels like coal, gas and oil
▪ The biosphere in living and dead organisms
Why is carbon important?
- regulates climate
- provides major building blocks for life on earth
What is carbon storage measured in?
Petagrams Pg
What are residence times?
The average length of time that material spends in a given pool
What are fluxes?
Fluxes refer to the movement/transfer of
carbon between stores.
Carbon store: Marine sediment and sedimentary rock
Easily the biggest store. 66,000 - 100,000 million billion metric tons of carbon. The rock cycle and continental drift recycle the rock over time, but this may take thousands, if not millions of years.
Carbon store: Oceans
The second biggest store contains a tiny fraction of the carbon of the largest store. 38,000 billion metric tons of carbon . The carbon is constantly being utilised by marine organisms, lost as an output to the lithosphere, or gains as an input from rivers and erosion.
Carbon store: Fossil fuel deposits
Fossil fuel deposits used to be rarely changing over short periods of time, but humans have developed technology to exploit them rapidly, though 4000 billion metric tons of carbon remain as fossil fuels.
Carbon store: soil organic matter
The soil can store carbon for over a hundred years, but deforestation, agriculture and land use change are affecting this store. 1500 billion metric tons of carbon stored.
Carbon store: atmosphere
Human activity has caused CO ₂ levels in the atmosphere to increase by around 40% since the industrial revolution , causing unprecedented change to the global climate. 750 billion metric tons of carbon stored.
Carbon store: terrestrial plants
Vulnerable to climate change and deforestation and as a result carbon storage in forests is declining annually in some areas of the world. 560 billion metric tons of carbon.
What is the geological carbon cycle?
- Very long turnover rate over 100,000 years
- Organic matter that is buried in deep sediments, protected from decay, takes millions of years to turn into fossil fuels. Carbon is exchanged with the fast component through volcanic emissions of CO2, chemical weathering, erosion, and sediment formation on the sea floor.
What is the biological carbon cycle?
- Carbon is sequestered in, and flows between, the atmosphere, oceans, oceans sediments, and on land in vegetation, soils and freshwater.
- relatively large exchange fluxes and rapid turnover rates
How is oil and natural gas formed?
Formed from the remains of tiny aquatic animals and plants. Gas and oil occur in pockets in rocks, migrating up through the crust until meeting caprocks. Natural gas, such as methane, is made up of the fractions of oil molecules, so small they are in gas form not liquid, usually found with crude oi. Other carbon deposits include oil shales, tar sands and gas hydrates.
How is coal formed?
Formed from the remains of trees, ferns and other plants. There are four main types:
- anthracite - the hardest coal, with the most carbon and therefore a higher energy content
- bituminous coals - second in hardness and carbon content
- soft coals such as lignite and brown coal are lower in carbon and energy potential; these are the major global source of energy supplies but emit more CO2 than hard coals
- peat is the stage before coal, an important carbon and energy source
What is lithification?
where freshly deposited loose grains of sediment are converted into rock
What is decomposition?
the breakdown of animals and plant structures by bacteria and the release of carbon compounds into the atmosphere, soil and to the ocean floor. Plants and animal particles from decomposition store carbon
What geological processes release carbon?
- Volcanic outgassing
- Chemical weathering
Explain volcanic outgassing
- Disturbance by volcanic eruptions or earthquake activity may allow pockets of CO2 that exist in the earths crust to be released into the atmosphere.
- Volcanoes currently emit 0.15-0.26 Gt CO2 annually, compared to humans emitting about 35 Gt annually, mainly from fossil fuel use, so volcanic degassing is relatively insignificant.
- An example of major degassing as a pulse is the 1991 eruption of Mt Pinatubo in the Philippines.
Where does outgassing occur?
○ Active or passive volcano zones associated with tectonic plate boundaries including subduction zones and spreading ridges
○ Places with no current volcanic activity such as the hot springs and geysers in Yellowstone National Park USA
○ Direct emissions from fractures in the earth’s crust
Explain chemical weathering
- The geological aspect of the carbon cycle interacts with the rock cycle.
- The processes through which the materials of the earth change can be broken down into 5 phases
- Chemical weathering - acid rain, formed from water reacting with atmospheric CO2 making carbonic acid, reacts with surface minerals, dissolving them into their component ions
- Transportation of calcium ions by rivers from the land into the oceans - the calcium ions combine with bicarbonate ions forming calcium carbonate and precipitate out as calcite and other materials
- Deposition and burial turns the calcite sediment into limestone
- Subduction occurs
- Some carbon rises to the surface within heated magma, then is “degassed” as CO2 and returned to the atmosphere. This is proved by diamonds (the purest form of carbon) being discovered to be formed up to 700km deep, proving that carbon is cycled between the earth’s surface and the lower mantle.
- The processes through which the materials of the earth change can be broken down into 5 phases
What is carbon sequestration?
Carbon Sequestration is the transfer of carbon from the atmosphere to other stores in solid or liquid form and can be both natural and artificial.
Why is photosynthesis important to the carbon cycle?
Living organisms convert Carbon Dioxide from the atmosphere and Water from the soil, into Oxygen and Glucose using Light Energy. By removing CO₂ from the atmosphere, plants are sequestering carbon and reducing the potential impacts of climate change.