Lesson 1 Intro to the Carbon Cycle

Prepare for Learning

A 4000 year old corpse

preserved in ice.

Why hasn’t it

decomposed?

Why is carbon important?

• Carbon is the main constituent of all living cells (biochemistry, organic chemistry)

• Component of fuel (coal and gas)

• Bacteria breaks down carbon, the absence prevents decomposition

Using these statements, have a go at drawing your own basic carbon cycle diagram.

Did it look

anything like this?

Learning Objectives- Key idea 6.1

Title: Global carbon terrestrial stores and the long-term geological cycle

a) The biogeochemical carbon cycle consists of carbon stores of different sizes (terrestrial, oceans and atmosphere), with annual fluxes between stores of varying size (measured in Pg/Gt), rates and on different timescales.

b) Most of the earth’s carbon is geological, resulting from the formation of sedimentary carbonate rocks (limestone) in the oceans and biologically derived carbon in shale, coal and other rocks.

c) Geological processes release carbon into the atmosphere through volcanic out-gassing at ocean ridges/subduction zones and chemical weathering of rocks.

For this lesson it will be useful to start your own Glossary for all the new terms we will be using. As this will continually be added to throughout the lessons and you will want to reorder (alphabetically) I advise you do this electronically.

The biogeochemical cycles Biogeochemical - relating to or denoting the cycle in which chemical elements are transferred between living systems and the environment

These include the carbon, hydrological and nitrogen cycles. These are natural processes that recycle nutrients in various chemical forms from the environment, to organisms, and then back to the environment.

The Carbon CycleThe carbon cycle is just one of these biogeochemical cycles. It can be defined as ‘the building blocks of life’, in which the exchange of carbon takes place between four main reservoirs—the atmosphere, the biosphere, the hydrosphere and the lithosphere.

1. Write out the definition and label where each sphere can be found on your diagram.

2. Then add these extra details to your terms:

- As dissolved CO2- As carbonates in limestone

and fossil fuels such as coal, oil and gas

- In living and dead organisms

- As carbon dioxide (CO2) and compounds such as methane (CH4)

Extra info: The 4 Spheres of Earth

• The area near the surface of the earth can be divided into four interconnected spheres: lithosphere, hydrosphere, biosphere, and atmosphere. Think of them as four interconnected parts that make up a complete system, in this case, of life on earth.

• Environmental scientists use this system to classify and study the organic and inorganic materials found on the planet.

The names of the four spheres are derived from the Greek words for stone (litho), air or vapor (atmo), water (hydro) and life (bio).

D_____ – the ending of life

B_________ – release of energy from fossil fuels

R____________ – the release of energy in living cells which produces Carbon dioxide

F____________ – consumers taking in food

P_____________ – the process by which a green plant makes its own food

D_________ – rotting down of dead organisms

B_____ A___ S____________ – formation of fossils

BURNING PHOTOSYNTHESIS DECAY DEATHFEEDING RESPIRATION

BURIAL AND SEDIMENTATION

Glossary

Present New Information

Present New Information

The Carbon Cycle

• Plants make carbon compounds from carbon dioxide they take from the air.

• This happens in photosynthesis.

• Animals obtain carbon compounds by eating plants or other animals, or both.

• Animals and plants return carbon back to the atmosphere as carbon dioxide when they respire.

• When animals and plants die, microbes digest them and obtain carbon compounds from their bodies.

• Microbes respire, this releases carbon dioxide into the atmosphere.

• Burning of wood and fossil fuels releases large amounts of carbon dioxide into the atmosphere.

• Human activities (anthropogenic) have caused an imbalance in the natural carbon cycle.

• There is now more carbon dioxide in the atmosphere than before.

The Carbon Cycle- Add the phrases in the right place

CO2 in air

CO2 is taken in by plants for photosynthesis and turned into carbohydrates

Plants release CO2 through respiration

The carbon taken in by plants is then eaten by animals

Animals (and plants) die and their remains are fed on by microbes

These microbes also release CO2

through respiration

Animals release CO2

through respiration

The Carbon Cycle

• Plants take in CO2 because they need carbon and oxygen to use in

• Through photosynthesis plants make

and other substances

e.g. protein

• When animals eat plants they use some of

the carbon containing compounds to grow

• Some carbon-containing compounds are

used to release energy by

photosynthesis

glucose (carbohydrate)

respiration.

Apply to Demonstrate New Understanding

This is a proportional diagram – it shows the amount of a component.

A Petagram(Pg) of carbon, also known as a Gigaton (Gt), is equal to one quadrillion (1,000,000,000,000,000) grams.

Using this diagram explain the carbon cycle. Discuss the size of the stores (atmosphere, hydrosphere, biosphere, lithosphere), the annual fluxes between stores and how much is in each store.

Review

Homework – complete the worksheet

The carbon cycle

True or false?

Review

Green plants use carbon dioxide in photosynthesis.

True

Combustion removes carbon from the atmosphere

False – combustion releases carbon

dioxide gas

The largest store of carbon is the atmosphere

False – more is found in geological

limestone rock deposits

Respiration adds carbon dioxide to the atmosphere

True

Respiration only occurs in animals

False – both animals and plants respire

Decomposers remove carbon dioxide from the atmosphere

False – they respire and release carbon

dioxide

Fossil fuels represent a huge (but decreasing) store of carbon

True

Increasing carbon dioxide may cause global cooling

False – scientists think it will cause global

warming

Energy is transferred from plants to animals to decomposers

True

Respiration releases energy to the environment in the form of heat

True