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THE CARBON CYCLE (Flows/Transfers (Combustion - (burning fossil fuels or…

- - - - Factors in the fast carbon cycles -
        The organic components are:
        Photosynthesis - the absorption of CO2 from the atmosphere (terrestrial plants) and from oceans (marine plants) to produce organic carbon structures.
        Respiration - the release of CO2 into the atmosphere, soil and oceans by animals as they exhale.
        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. Where oxygen is present it releases CO2, where it is absent CH4is released.
        Digestion - the release of carbon compounds by terrestrial and marine animals after feeding on carbon-rich material.
        Combustion- natural fires release carbon compounds from vegetation to the atmosphere
        The non-organic factors are:
        Ocean-atmosphere exchange- there is a mutual transfer of CO2 between the lower atmosphere and ocean surfaces. The flow can go in either direction depending on the balance of CO2 between the two stores, temperature and conditions of air and water, but the prevailing direction is from the atmosphere to the ocean.
        Variations in the earths orbit (Milankovitch cycles)
        Volcanic eruptions (Eruption return carbon to the atmosphere that has been trapped for millions of years in rocks - volcanoes emit between 130 - 380 million tonnes of CO2 per year)
      - Factors in the slow carbon cycle -
        The transfer of carbon into the oceans from the atmosphere and land surface - Direct CO2 absorption as part of the atmosphere-ocean exchange is supplemented by the erosion of carbon-rich terrestrial surfaces as naturally-acidic rainfall dissolves surface rocks and transfers soluble bicarbonate compounds, via rivers, to the sea.
        The deposition of carbon compounds on the ocean floor - Marine plants (including phytoplankton) absorb CO2 and marine creatures take in carbon to construct skeletons and shells. Phytoplankton are consumed by zooplankton and their carbon-rich excrement falls to the ocean floor. The skeletal and shell remains of marine creatures also fall the sea bed.
        The conversion of ocean sediments into carbon-rich rock - On continental shelves carbon-rich accumulations of deposits may be converted into carbon-rich rocks (such as chalk and limestone) or become contained as concentrations within sandstones and shales to form organic deposits, some of which become fossil-fuel reserves in time. This process of sedimentary rock formation is called lithification.
        The transfer of carbon rocks to tectonic margins - As sedimentary rocks are created by heat and pressure over millions of years, they are also moved in the direction their crustal plate is moving. If they eventually become a collision margin, they may be uplifted to become surface mountain ranges (as in the Himalayas). The carbon-rich strata may then be exposed to weathering and erosion to return to the ocean as eroded carbonate rocks.
        The return of carbon compounds to the atmosphere in volcanic eruptions - At subduction zones, carbon-rich rocks may be ejected at the surface from volcanic eruptions, usually in the form of gaseous compounds into the atmosphere. Here, CO2 contributes to the formation of carbonic acid in clouds, which then begins the process of solution of surface rocks and a starting of the terrestrial component again, or being absorbed by ocean surfaces for the marine component.
      - The earth goes through stages of stable climate when carbon cycles are in a state of dynamic equilibrium
    - - The carbon cycle in the oceans (Aquatic)
        There are three aquatic processes:
        Solubility Pump - Diffusion (movement of) Co2 from atmosphere into seas, the water is taking in the Co2.
        15-40% of anthropogenic carbon diffuses into the sea, if rates of carbon continue to increase the sea simply wont be able to cope with this volume. As the Co2 is taken into the water
        HO2 + Co2 = carbonic acid
        Carbonate Pump - This carbonic acid is then taken in by the phytoplankton which they use to make there shells. The phytoplankton release Co2 when they are making their shells, this is surface Co2 and goes into the atmosphere. When the phytoplankton and the marine life that eats them they sink, get buried and compacted to form marine sediments in the deep ocean. Over millions of years they form rock this is known as 'LITHIFACTION'
        Upwelling - In cold latitudes, water sinks pulling down Co2. Which cycles round and rises again when it reaches warmer waters. This is the fast carbon cycle.
        Deep ocean = Slow carbon cycle
        Surface Carbon = Fast carbon cycle
        Terrestrial runoff also adds carbon to the aquatic cycle from rivers. It gets into the rivers via weathered rock that releases dissolved carbon into those rivers as well as the carbon from acid rain. This then gets into the ocean adding more carbon.
        Ocean acidification is happening due to the ocean having to absorb way to much Co2, the pH is therefore going down and becoming more acid. The impact of this is that its harder for phytoplankton to make their shells, this is eventually slowing down the carbonate pump.
        Warmer oceans absorb less carbon than cold oceans, because diffusion is slowed.
        The ocean was a SOURCE of Co2 before the industrial revolution - now it is a SINK
        
        The carbon cycle in the atmosphere
        Atmospheric carbon is usually CO2 or Methane
        CO2 combines with water in the clouds to form natural acid-rain this leads to terrestrial weathering
        Outputs from the atmosphere include absorption from the surface vegetation and by oceans in atmosphere-ocean gas exchange
        
        The serial carbon cycle
        Found after volcanic eruptions where plants develop on bare rock
        
        Rock - where carbon is stored
        
        Weathering breaks down rock releasing carbon and in time a soil forms (another carbon store)
        
        Soil attracts plants which cycles the carbon between soil, atmosphere and plants
        
        Overtime, plants help develop the soil = larger carbon store
        
        This plant succession ends with the climatic climax community (EG- In UK an Oak woodland)