booklet 2 - flows + transfers

• transfers / fluxes: processes by which carbon moves between stores
• net carbon sink: more carbon enters a store than leaves it
• net carbon source: If more carbon leaves a store than enters it.
• what are the factors driving change in the carbon cycle - fast cycle: photosynthesis

  respiration

  combustion

  biological carbon pump

  decomposition

  ocean-atmosphere exchange
• what are the factors driving change in the carbon cycle - slow cycle: carbon sequestration in oceans + sediments

  weathering + volcanoes
• what is the fast carbon cycle? time it takes for carbon to move through cycle is measured in a lifespan
• what is the slow carbon cycle? can take place over many tens + hundreds of millions of years
• what is a carbon pump? - mechanism that drives carbon from one zone to another

  - generates transfers of carbon
• what are the two carbon pumps? ocean-atmosphere exchange

  biological carbon pump
• photosynthesis: - plants use energy from sun to produce carbohydrates in form of glucose

  - green plants absorb light with chlorophyll

  - energy converts CO2 into glucose + releases oxygen

  - glucose used in plant growth
• respiration: - chemical process occurring in all cells

  - glucose converted into energy that's used for growth + repair and controls body temp

  - CO2 returned to atmosphere
• decomposition: - when organisms die, they're consumed by decomposers (eg worms, bacteria + fungi)

  - during process, carbon is released as CO2

  - some organic material passed into soil + stored
• biomass combustion: - organic material contains carbon

  - burned in with oxygen, matter is converted into energy, CO2 and water

  - CO2 released to atmosphere, returning the carbon that has been stored in the rocks
• what is thermohaline circulation? - water sinks due to cooling + becoming more dense

  - also due to being saline (heavier)

  - becomes saline due to salt sinking to bottom of ice
• the oceanic carbon pump: - at ocean surface, theres exchange of CO2

  - some CO2 dissolves into water + some goes into atmosphere

  - warmer ocean = less carbon taken in + stored in sea
• ocean temperatures + CO2: - negative correlation

  - warm water in currents carried from tropics to polar regions

  - here, water cools + becomes dense enough to sink below surface (downwelling)

  - when water returns to surface (upwelling) + warms, it loses CO2 to atmosphere
• what does the oceanic carbon pump give? gives ocean more carbon than it would have if surface water wasn't constantly replenished
• the oceanic carbon stores - impact of global warming: the warmer the ocean gets, less carbon stored in it + so more carbon in atmosphere
• the oceanic carbon stores - impact of weakening thermohaline cycle: will weaken downwelling + so less storage will occur
• how do the oceanic carbon pump and thermohaline cycle act as carbon sinks? - oceanic carbon pump means water exchanges CO2

  - thermohaline cycle transports carbon absorbed at surface down to ocean bed, creating carbon sink
• biological carbon pump: - During the carbon cycle, CO2 is naturally removed from the atmosphere

  - Over thousands of years, fraction of it is sequestered in the oceans for prolonged periods of time

  - Dead phytoplankton and other organisms drive this pump as they sink towards the bottom of the ocean
• burial and compaction: - organisms compacted into sediments to form rock

  - sediments containing carbon may form hydrocarbons
• geological carbon cycle: - takes place over millions of years

  - involves cycling carbon through various layers of rock
• role of chemical weathering in carbon cycle: CO2 from atmosphere dissolves in rainwater, forming carbonic acid

  weak acid reacts with limestone - carbonation
• impact of chemical weathering in carbon cycle: - removes CO2 from atmosphere + stores it as dissolved carbon in hydrosphere

  - overtime, forms calcium carbonate in shells, which becomes limestone

  - locks carbon in long term store
• wheres the primary source of carbon from? - earths mantle

  - volcanoes release 200 million tonnes of carbon per year
• carbon sequestration: capturing CO2 out of atmosphere + placing it in long term storage
• terrestrial sequestration: use of plants to capture CO2 from atmosphere + store it in plants and soil
• oceanic sequestration


  The storing of CO2 dissolved in seawater
• the carbon budget: balance of carbon exchanges between 4 major carbon stores

  uses data to describe amount of carbon stored + transferred within carbon cycle
• local scale transfer of carbon - a tree: - carbon fixation = process of converting CO2 gas to living organisms to grow

  - amount of carbon stores depends on balance between photosynthesis + respiration
• whats a sere?


  succession (complete vegetation succession)
• seral scale transfer of carbon - deciduous woodland: - bare soil

  - pioneer grasses -> plants take in CO2 from atmosphere + store it as biomass

  - shrubs

  - bacterial decomposition releases CO2 back into atmosphere