The Carbon Cycle

BC Science Probe 10Section 4.2

The Carbon Cycle

• The diagram of the carbon cycle looks very complicated, but you only need to understand how it works.

• You don’t need to memorize it!

The Carbon Cycle

• The way the carbon cycle works is really quite easy to understand as it is mostly common sense.

• You only really need to know the meanings of some basic terms:

The Carbon Cycle

• Carbon source:• Any source of carbon that releases more carbon than it

stores.

• i.e.– Burning fossil fuels – coal, oil, natural gas– Burning trees/wood – Erupting volcanoes

The Carbon Cycle

• Carbon reservoir:– Any place where carbon is stored and not

released.• i.e.– Living trees – the carbon is stored as

carbohydrates.– Oceans – dissolved carbon from the atmosphere.– Shells of marine organisms as CaCo3.

– Limestone as CaCo3.

The Carbon Cycle

• Carbon sink:– A place where more carbon is stored than is

released (the opposite of a carbon source).• i.e.– Forests– Oceans– Soil – in organic matter.

The Carbon Cycle

• Atmospheric carbon:– Carbon found in the form of CO2 gas in the

atmosphere after being released by a carbon source.

• i.e.– Combustion– Volcanoes– Cellular respiration

How the Carbon Cycle Works

• How does carbon from the earth become atmospheric carbon dioxide?– From:• Factories• Cars• Cellular respiration• Burning wood

How the Carbon Cycle Works

• How is some of this atmospheric carbon returned back to the earth?– By:• Some dissolves in oceans, lakes and rivers.• Some used by plants for photosynthesis.

How the Carbon Cycle Works

• How is some of this atmospheric carbon returned to the oceans?– By:• Weathering of rocks like limestone.• Dissolves as CO2.

How the Carbon Cycle Works

• How does some of this carbon on the surface of the earth become buried deep beneath the earth?– By:• Dead plants and animals decompose and

become covered in layers of earth.• Carbon compounds are compacted and turned

into fossil fuels.

How the Carbon Cycle Works

• How does the carbon stored in the depths of oceans and lakes become buried deep beneath these bodies of water?– By:• Aquatic plants and animals die and fall to the

bottom to be buried in sediments (sedimentation).

How the Carbon Cycle Works

• How might this buried carbon be returned back to the surface of the earth?– By:• Geological events:–Earthquakes–Volcanoes

• Drilling and mining of fossil fuels.

The Greenhouse Effect

The Greenhouse Effect