3.1.1.3 The Carbon Cycle Flashcards
what are the gaseous carbon compounds?
CO2 and methane (CH4)
what are the liquid carbon compounds?
carbonic acid, calcium bicarbonate
what is the solid carbon compound?
carbonate rocks
how is carbon stored in the atmosphere?
as co2 - 0.04% of the atmosphere or 400parts per million
or methane
where is carbon found in the biosphere?
living vegetation, soil humus, peat, animals
where is carbon found in the cryosphere?
in permafrost - e.g. canada
where is carbon found in the lithosphere?
sedimentary rocks like limestone and chalk
fossil fuels / gas / oil
where is carbon found in the hydrosphere?
dissolved CO2 in water and sea floor sediments
ocean plants
plankton
rank largest to smallest magnitude of stores of carbon
lithosphere - sedimentary rocks hydrosphere - oceans cryosphere - permafrost biosphere - living biomass atmosphere
what are the transfer processes in the carbon cycle?
photosynthesis repiration decomposition combustion carbon sequestration weathering
outline the process of photosynthesis
plants use sunlight energy to produce glucose by converting CO2 into carbohydrates and oxygen is released back to the air
outline the process of respiration
all living things use glucose and energy to carry out life functions through the process of respiration
CO2 and water are returned to the atmosphere
approx 50% of all carbon absorbed by photosynthesis is released by respiration
outline the process of decomposition
when decomposers break up organic material
carbon is returned to the atmosphere as CO2 or methane
or passed into the soil as humus where it is used for plant growth
outline the process of combustion
when organic material is burnt in the presence of oxygen and is converted into CO2, energy and water.
during this process carbon transfers from th bio/lithosphere to the atmosphere
outline the process of carbon sequestration
long term transfer of carbon from the atmosphere to plants, soils, rocks and oceans
outline the process of weathering
sedimentary rocks are broken down over time
when co2 is absorbed by water it forms carbonic acid which causes rocks to slowly dissolve. is eventually washed away into the oceans where it is used by marine life to build shells
transfers carbon from the lithosphere to the hydrosphere
give examples of the fast carbon cycle when processes cause rapid change
photosynthesis - gaseous exchange between the ocean and atmosphere
wild fires - can transfer carbon rapidly from the biosphere to the atmosphere in huge amounts
Outline the workings of the carbon cycle at the scale of an individual tree
Trees are 50% carbon
Photosynthesis, respiration and decomposition transfer between biosphere and atmosphere
What is a lithosere?
A succession that takes place on bare rock like solidified lava flow or a raised beach
Outline the role of volcanic activity in the carbon cycle
It transfers inorganic carbon from the lithosphere to the atmosphere.
Rock formed by igneous processes will slowly weather to carbonate solution
How much carbon do volcanoes produce a year?
130-380 million tonnes
Outline the role of wilfires in the carbon cycle
Combustion transfers large amounts of carbon from the biosphere to the atmosphere quickly
Extensive wildfires can turn forests from being a carbon sink to being a carbon sourcw
Outline the impacts of hydrocarbon extraction and use on the carbon cycle
Carbon is released from long term storage as fossil fuels when burnt into the fast carbon cycle
When did fossil fuel consumption and combustion rapidly increase?
1850s after industrial revolution
1950 chinese industrialisation led to a dramatic increase in the release of CO2
What is the largest anthropogenic contributor to atmospheric CO2?
fossil fuel consumption
What happens when limestone is processed into cement and why?
Significant amiunts of CO2 is released because sedimentary rocks like limestone are rich in calcium carbonates
How do farming practices change the carbon cycle?
Practices such as ploughing, harvesting, rearing livestock and using large machinery release carbon
Methane is released in large amounts by livestock farming and rice cultivation
How does deforestation impact the carbon cycle?
Removal of important carbon stores and sinks which reduces soil carbon content and closes down photosynthesis
How much of anthropogenic CO2 emissions does deforestation account for?
20%
How does land use change impact upon the carbon cycle?
Reduces vegetation coverage and replaces surface areas with impermeable surfaces
Urban settlements consume large amounts of energy
Cement is used in many urban structures which emits huge amounts of CO2
What is the carbon budget?
The surplus or deficit of carbon once carbon output is subtracted from carbon input
Outline the greenhouse effect
Short wave solar radiation passes throuhg the earth’s atmosphere and warms the earths surface
Long wave radiation is then emitted by the earth, some of which is absorbed by greenhouse gas molecules which directly warms the earths surface and atmosphere
Why are greenhouse gases so important?
Without them, the earth would be completely frozen and too cold for life existence at -180°c
Explain the concern about the enhanced greenhouse effect
The increased concentration of CO2 and methane means that more infra red radiation is being trapped in the atmosphere which explains why average global temperatures have increased about 0.8°c since 1880
If CO2 levels continue to rise, how much is Earth temperatures expected to rise by 2100?
4°c
How much have global temperatures risen since 1880?
0.8°c
Outline possible impacts of increasing atmospheric CO2 on the land
Increase the length in growing season for plants, more CO2
Melting permafrost in tundra regions
Increasing extreme weather
outline possible impacts of increasing atmospheric CO2 on the oceans
- increasing acidity of the water
- increasing temperatures cause phytoplankton numbers to decrease as they are used to cooler waters
- melting sea ice, rising sea levels
- fresh water entering the oceans reduces the salinity
what does the increasing acidity of oceans impact?
dissolves shells of animals
causing coral bleaching
what happens as a result of decreasing numbers of phytoplankton in the seas?
decrease the effectiveness of oceans being a carbon sink because plankton sequester carbon from the atmosphere
how can warming oceans be a negative feedback loop?
some oceans support some species of phytoplankton and its growth. these species release DMA molecules which act as condensation nuclei for cloud formation . leads to potential global cooling
why do warmer oceans mean less sea ice?
sea ice has a high albedo and reflects heat.
as it is replaced by water, which has a much lower albedo, there is further warming of the oceans.
how much are sea levels expected to rise by 2100?
0.8 and 2m as a result of thermal expansion and melting ice sheets
