4.3/4.4

4.3/4.4 - Carbon Cycle and Climate change

DCS Topic Code	Statement	Guidance
4.3.U1	Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds.
4.3.U2	In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen carbonate ions.
4.3.U3	Carbon dioxide diffuses from the atmosphere or water into autotrophs.
4.3.U4	Carbon dioxide is produced by respiration and diffuses out of organisms into water or the atmosphere.
4.3.U5	Methane is produced from organic matter in anaerobic conditions by methanogenic archaeans and some diffuses into the atmosphere or accumulates in the ground.
4.3.U6	Methane is oxidized to carbon dioxide and water in the atmosphere.
4.3.U7	Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils.
4.3.U8	Partially decomposed organic matter from past geological eras was converted either into coal or into oil and gas that accumulate in porous rocks.
4.3.U9	Carbon dioxide is produced by the combustion of biomass and fossilized organic matter.
4.3.U10	Animals such as reef-building corals and mollusca have hard parts that are composed of calcium carbonate and can become fossilized in limestone.
4.3.A1	Estimation of carbon fluxes due to processes in the carbon cycle.	Carbon fluxes should be measured in gigatonnes.
4.3.A2	Analysis of data from air monitoring stations to explain annual fluctuations.
4.3.S1	Construct a diagram of the carbon cycle.

DCS Topic Code	Statement	Guidance
4.4.U1	Carbon dioxide and water vapour are the most significant greenhouse gases.
4.4.U2	Other gases including methane and nitrogen oxides have less impact.	The harmful consequences of ozone depletion do not need to be discussed and it should be made clear that ozone depletion is not the cause of the enhanced greenhouse effect.
4.4.U3	The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere.	Carbon dioxide, methane and water vapour should be included in discussions.
4.4.U4	The warmed Earth emits longer wavelength radiation (heat).
4.4.U5	Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere.
4.4.U6	Global temperatures and climate patterns are influenced by concentrations of greenhouse gases.
4.4.U7	There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures.
4.4.U8	Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.
4.4.A1	Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.
4.4.A2	Correlations between global temperatures and carbon dioxide concentrations on Earth.
4.4.A3	Evaluating claims that human activities are not causing climate change.

4.3_4.4_carbon_cycle_greenhouse_effect.ppt
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