Carbon Cycle June 2024 Exam
Quiz Study Guide
Carbon Cycle - Answer>>Largest Carbon Store = Lithosphere/
Sedimentary (100,000,000 PgC)
Largest yearly flux = Photosynthesis (103 PgC from Atmosphere
560 to Biosphere 2,060)
Smallest Carbon Store = Atmosphere/ Plants (both 560 PgC)
Smallest yearly flux = Sedimentation/ fossilisation (0.2 PgC from
Deep Oceans 38,000 to Fossil Fuels 4,000)
Geological carbon formation - Answer>>1. Coal = duration and
heat intensity influences %C
2. Limestone = compaction/cementing of shells
3. Crude Oil = chemical decomposition of dead phytoplankton
Geological processes that release carbon -
Answer>>Outgassing and Partial melting of sedimentary rocks
Outgassing - Answer>>Release of CO2 in crust by volcanic
eruptions/earthquake activity (geysers/ hot springs)
Geological carbon cycle - Answer>>Slow (10-100 million tonnes
carbon/year) , huge carbon store
Anthropological carbon cycle - Answer>>Human caused, fast
(1,000 million tonnes carbon/year)
Biological carbon cycle - Answer>>Fast (10,000-100,000 million
tonnes carbon/year), flows and sequester between oceans,
vegetation and freshwater
, Phytoplankton - Answer>>Carry out photosynthesis by taking
out carbon from seawater which enables more carbon to enter the
sea (1,000 x more than respiration)
Biological pump - Answer>>Organisms feed on phytoplankton
and use carbon to make their shells (Calcium Carbonate). Carbon
moves from shallow to deep ocean when organisms die and sink
Carbonate pump - Answer>>Organisms remains turn into
sedimentary rock
Thermohaline Circulation - Answer>>System of surface and
deep ocean currents driven by temperature and salinity
differences. CO2 dissolves more readily in cold and deeper water
(25% diffused in Southern Ocean).
Physical pump - Answer>>Cold, denser seawater sinks into
deep ocean, where slow moving currents hold CO2. Deep
currents then return to the surface, warmed and diffuse CO2 back
into the atmosphere.
Terrestrial Carbon Cycling - Answer>>CO2 taken out of
atmosphere by plants photosynthesis (1000x more than
respiration), which is then eaten by consumers and later released
back into the atmosphere during decomposition.
Photosynthesis Equation - Answer>>
Biological decomposition - Answer>>Decomposers (worms)
feed on dead matter and break down into CO2, water and
nutrients. Soils store 20-30% carbon but can emit or sequester
CO2 depending on climate, soil type and management
Greenhouse gases - Answer>>CO2, CH4, CFCs, N2O