Energy transfers - Carbon and water cycles

What is the carbon cycle?

The carbon cycle describes how carbon molecules move between organisms and the abiotic world

Describe the stages of the carbon cycle.

1. Photosynthesising plants remove CO2 from the atmosphere

2. Eating consecutive trophic levels passes carbon compounds along a food chain

3. Respiration in plants and animals returns CO2 to the atmosphere

4. Organisms die and decompose so bacteria and fungi break down dead material and release CO2 via respiration

5. Combustion of materials (e.g. wood, fossil fuels) releases CO2

Carbon cycle diagram.

NTK

What is the water cycle?

The continuous movement of water from the ocean to the atmosphere to the land and back to the ocean

Describe the stages of the water cycle.

1. Energy from the sun evaporates water from sources such as lakes and oceans. Transpiration also releases water vapour.

2. Water vapour rises, cools and condenses forming clouds

3. Precipitation occurs

4. Water is absorbed by the soil and taken up by roots. Some is used in photosynthesis or becomes part of the plant, entering the food chain.

5. Excretion returns water to the soil

6. Surface runoff returns to streams, rivers and eventually the sea

Diagram of the water cycle.