4.3 Carbon Cycle

IB Syllabus Statements

Understandings:

Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds.
In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogencarbonate ions.
Carbon dioxide diffuses from the atmosphere or water into autotrophs.
Carbon dioxide is produced by respiration and diffuses out of organisms into water or the atmosphere.
Methane is produced from organic matter in anaerobic conditions by methanogenic archaeans and some diffuses into the atmosphere or accumulates in the ground.
Methane is oxidized to carbon dioxide and water in the atmosphere.
Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils.
Partially decomposed organic matter from past geological eras was converted either into coal or into oil and gas that accumulate in porous rocks.
Carbon dioxide is produced by the combustion of biomass and fossilized organic matter.
Animals such as reef-building corals and mollusca have hard parts that are composed of calcium carbonate and can become fossilized in limestone.

Applications and skills:

Application: Estimation of carbon fluxes due to processes in the carbon cycle.
Application: Analysis of data from air monitoring stations to explain annual fluctuations.
Skill: Construct a diagram of the carbon cycle.

Discuss the importance of making accurate, quantitative measurements with respect to measurements of carbon dioxide and methane concentrations in the atmosphere.
What do autotrophs do?
In what form is carbon present in aquatic ecosystems?
How does carbon dioxide get from the atmosphere or water into autotrophs?
What are the sources of carbon dioxide?
Outline the production of methane by methanogenic archaeans.
Outline the oxidation of methane.
Explain how peat forms.
Outline how coal, oil and gas were formed.
Outline the significance of the combustion of biomass.
Outline the significance of the presence of fossilized organic matter.
Relate reef-building corals and Mollusca to fossilization in limestone.
Explain the importance of and method for estimating carbon fluxes due to processes in the carbon cycle.
Explain how air monitoring stations are used to determine annual fluctuations.
Explain how to construct a diagram of the carbon cycle.
What unit are carbon fluxes measured in?