UNIT ____: Carbon Cycle                                 Name: ________________________

Essential Idea(s):

Continued availability of carbon in ecosystems depends on carbon cycling.

IB Assessment Statements and Class Objectives

4.1.U9:  Autotrophs and heterotrophs obtain inorganic nutrients from the abiotic environment.

• Define nutrient.
• List the common nutrients needed by organisms.
• Outline how nutrients enter living systems.

4.1.U10:  The supply of inorganic nutrients is maintained by nutrient recycling.

• State that chemical elements can be recycled but energy can not.
• Outline the generalized flow of nutrients between the abiotic and biotic components of an ecosystem.

4.3.A1:  Estimation of carbon fluxes due to processes in the carbon cycle.

• List flux processes in the carbon cycle.
• State the unit of measure for carbon flux values.  

4.3.U3:  Carbon dioxide diffuses from the atmosphere or water into autotrophs.

• State that in diffusion, molecules move from an area of higher concentration to an area of lower concentration.
• Outline the role of diffusion in the carbon cycle.

4.3.U1:  Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds.

• State the role of photosynthesis in the carbon cycle.

4.3.U4:  Carbon dioxide is produced by respiration and diffuse out of organisms into water or the atmosphere.

• State that carbon dioxide is a waste product of aerobic cellular respiration.
• State that carbon dioxide diffuses out of cells into the atmosphere or water.

4.3.U5:  Methane is produced from organic matter in anaerobic conditions by methanogenic archaea and some diffuses into the atmosphere or accumulates in the ground.

• Outline the role of methanogenic archaea in the transformation of organic material into methane.

4.3.U6:  Methane is oxidized to carbon dioxide and water in the atmosphere

• State that methane is oxidized to carbon dioxide 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.

• Define peat.
• Outline formation of peat.

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.

• Outline formation of coal.
• Outline formation of oil and natural gas.

4.3.U9:  Carbon dioxide is produced by combustion of biomass and fossilized organic matter.

• Define combustion.
• State the products of a combustion reaction.
• State sources of fuel for a combustion reaction.

4.3.A2:  Analysis of data from air monitoring stations to explain annual fluctuations.

• Sketch a graph of the annual fluctuation in atmospheric carbon dioxide concentration.
• Explain the annual fluctuation in atmospheric carbon dioxide concentration in the northern hemisphere.

4.3.U2:  In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen carbonate ions.

• Outline the process that converts CO2 to hydrogen carbonate ion in water, leading to a reduction of the pH in the water.

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.

• State that hard shells, such as in mollusk and coral, are made of calcium carbonate.

4.3.S1:  Construct a diagram of the carbon cycle.

• Define pool and flux.
• Draw a diagram of the terrestrial carbon cycle.
• Draw a diagram of the aquatic carbon cycle.

Nutrient Cycles

The Carbon Cycle

The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main element found in biological compounds as well as a major component of many minerals such as limestone.

Carbon moves between POOLS via eight FLUX processes.

Global carbon fluxes are estimated in gigatons of carbon per year

Fossil Fuels

• COAL

• OIL & GAS

Combustion

Methanogenic Archaea

Methanogens are prokaryotic cells in the domain Archaea that produce methane as a byproduct of their anaerobic respiration.  Methane is oxidized in the atmosphere to form CO2 and H2O.

Prokaryotic cells:

Domain Archaea:

Methane:

Anaerobic respiration:

Oxidation:

Seasonal CO2 Fluctuations in the Northern Hemisphere

      J    F    M    A    M    J    J    A    S    O    N    D

CO2 in H2O

In plain water (neutral pH), dissolved calcium ions (Ca2+) will bond with the carbonate (CO32-) to form calcium carbonate which is used by marine animals to form shells.

OCEAN ACIDIFICATION:

With more CO2 diffusing into the water, the acidity of the solution increases and the solubility of calcium carbonate increases .  This dissolves the calcium carbonate in the solid shell into calcium ions and carbonate ions in the surrounding ocean water.