Carbon Cycle - Geological Carbon Cycle

Overview:
  • Terrestrial means land and include vegetation (biosphere)
  • Biogeochemical carbon cycle is basically all living things, and chemicals
  • The carbon cycle is extremely important for ‘planetary health’. It provides carbon as a building-block for life, and carbon dioxide regulates the temperature of our climate by trapping solar energy. Without carbon dioxide, the world would freeze.
Basics:
  • Store = the amount of carbon in a store measured in Petagrams
    • Main stores are terrestrial, oceanic, atmospheric
  • The flux rate is a measure of how much carbon leaves or enters a store in a year (GtC/year)
  • Turnover time = total store (GtC) / flux rate (GtC per year)
  • In a well-mixed system e.g. the atmosphere, residence time of CO2 molecules are the same as the turnover time
Carbon Store:
Size Of Store:
Flux Rate:
Turnover:
Terrestrial (earth, rocks and soil)
Enormous – most of the Earth’s stores
Low
Very slow (millions of years)
Oceans
Big (deep ocean)
Medium
Medium – deep ocean slower (thousands of years)
Atmosphere
Small
High
Faster turnover
Biosphere (vegetation)
Quite fast.

Sedimentary Rocks:
Weathering, erosion and deposition > sediment > compaction & cementation
Fossil Fuel Formation:
  1. Ancient forests lived
  2. And died
  3. And were buried and compressed by tectonic forces
  4. To form coal, oil and gas
    1. Over millions of years increasing heat and pressure forms fossil fuels in the ground storing in coal or shale.
The Role Of Geology:
  • Geological processes like volcanoes release carbon dioxide and weathering and erosion of sedimentary rocks like chalk release sediments with carbon in. e.g erosion and weathering in Flamborough Head releases carbon.
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