Natural Flows

• Combustion occurs when any organic material is reacted (burned) in the presence of oxygen.
• The organic material burnt in combustion can be vegetation, fossil fuels and peat. Fires burn 3-4 million km^2 of Earth's land surface area each year.
• Increasingly large and/or more frequent fires, possibly made worse by warming temperatures and precipitation levels can change the carbon balance.
• Forest fires occur mostly in Boreal forests (such as in Alaska or Canada) and Savannah Grasslands (such as in Africa).
• Decomposition includes physical, chemical and biological mechanisms that transform organic matter into increasingly stable forms.
• Detritivores are microorganisms that carry out the process of decomposition.
• Detritivores cannot survive in organic matter stores, such as peat, due it being saturated with no oxygen. Therefore carbon and dead plants remain in the soil for a very long time.
• Decomposition ensures that important elements, including carbon, is recycled continuously in the soil and made available for life.
• Photosynthesis is the process of using energy from the sunlight, water and carbon dioxide to form carbohydrates.
• Phytoplankton (in the sunlit, surface waters), photosynthetic algae and bacteria turn the carbon into organic matter by photosynthesis.
• Carbohydrates are an energy store which hold carbon.
• Oxygen is by-product of photosynthesis which gets released into the atmosphere which can be used for human respiration.
• Respiration takes oxygen from the atmosphere and replaces it with carbon dioxide. The by-products of this process are water and carbon dioxide.
• Plants and photosynthetic algae use some of the stored carbohydrates as an energy source to carry out their life, through respiration.
• Photosynthesis is the opposite process to respiration however they do not balance out as not all organic matter is oxidised (some is buried in sedimentary rocks). This results in more oxygen being put into the atmosphere and carbon dioxide removed by photosynthesis.
• Carbon sequestration is the natural or artificial process by which carbon dioxide is removed from the atmosphere and held in sold or liquid form in the hydrosphere.
• Vertical Deep Mixing occurs when warm water in oceanic surface currents is carried from the warm tropics to the cold polar regions where it cooled making it dense enough to sink. When the cold water returns to the surface and warms up again, it loses the carbon dioxide to the atmosphere.
• The amount of the carbon dioxide released by Volcanoes have not been enough to produce detectable change due to the sulphur dioxide being emitted which forms fine droplets.
• Volcanic eruptions can also release large amounts of ash into the air which blocks incoming solar radiation and reduces global temperatures.
• The sulphur dioxide produced cools the earth's temperatures and converts into the sulphuric acid forming fine droplets, increasing the reflection of the sun into space.