Carbon Lesson 3: Geological Carbon Cycle Flashcards
What are the key processes of the geological carbon cycle?
Weathering of rocks - mechanical, chcemical and biological
Decomposition
Transportation
Sedimentation
Metamorphosis
Describe the 3 types of weathering?
Mechanical = break down of rocks by shattering - ice expands in cracks by 10% causing the rock to break apart
Chemical = break down of rock by carbonic acid in rain - dissolves rock
Biological = burrowing animals or roots of plants breaks down rock
Describe decomposition
Plant and animal particles result from decomposition by bacteria, fungi and earthworms removing carbon from dead organisms or from surface erosion
Describe transportation
Rivers carrying particles to the ocean where they are deposited
Describe sedimentation
Sediments accumulate, burying older sediment
Describe metamorphosis
Layering and burial of sediment building pressure, causing sediment to turn into rock, shale to slate, limetsone to marble.
What % of carbon containing rock is from calcifying organisms and plankton?
80%
What % of carbon is from organic carbon embedded in mud?
20%
How much CO2 do volcanoes release each year?
300 million tonnes
What is the crustal/terrestrial/geological carbon store?
Long-term store = sedimentary rocks, very slow cycling over millenia
What is the oceanic (deep) carbon store?
Long-term store = Most carbon is dissolved as inorganic carbon stored at great depths, very slowly cycled
What is the terrestrial carbon store?
Short-term store = from plant materials (biomass) microorganisms break most organic matter down into CO2 in a process which takes days in a hot and humid climate to decades in colder climates
What is the oceanic (surface) carbon store?
Short-term store = exchanegs are rapid with the atmosphere through physical processes such as CO2 dissolving in the water and biological processes involving plankton. Some of this carbon sinks into the deeper ocean pool
What is the atmospheric carbon store?
Short-term store = CO2 and CH4 store cabon as GHGs with a lifetime of up to 100 years
What is the terrestrial ecosystems carbon store?
Short-term store = CO2 is taken from the atmosphere by photosynthesis, carbon is stored organically, especially in trees. Rapid exchange with the atmosphere - seconds/minutes
