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Nutrient Cycles

Water cycleCarbon cycleNitrogen cycle

Phosphorus cycle

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Water cycle

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• All living things need water because the cytoplasm in cells is composed mostly of water.

• The chemical reactions that support life must take place in water

• The electrical impulses produced by nerves are transmitted through water.

Water cycle

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How does water move through the environment?

• Precipitation – water falls from the sky as rain, snow or sleet

• Evaporation – water returns to the atmosphere as a gas

• Waste – animals release liquid waste• Respiration – water is product of cellular

respiration• Runoff and streams carry water from place

to place in the environment.

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Why is carbon Important?

• All of the macromolecules contain carbon.• Carbon is used to make sugars which

provide living things with energy. • The carbon containing macromolecules

are the building blocks of all life.

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How does carbon move through the environment?

• Photosynthesis – pulls CO2 from the air and uses it to make sugars.

• Consumption – one organism eats another and gets its carbon.

• Respiration – cellular respiration releases CO2 back to the air as it breaks down sugars

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How does carbon move through the environment?

• Decomposition – as dead organisms are broken down, the carbon is released to the soil or back to the air.

• Deposition – the remains of dead organisms can be converted to fossil fuels

• Burning – releases CO2 back to the air when organisms or fossil fuels are burned.

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Why is Nitrogen important?

• Nitrogen is an element that is found in amino acids.

• Amino acids join together to form proteins• Proteins help living things carry out life

processes.

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How does Nitrogen move through the environment?

• Nitrogen gas makes up most of our air but organisms can’t use it in this form.

• Nitrogen fixation – bacteria, lightning and fertilizer factories take Nitrogen from tha air and convert it into forms organisms can use

• Plants take in nitrates from the soil to make amino acids

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How does Nitrogen move through the environment?

• Consumption – organisms eat each other and obtain their nitrogen

• Decomposition and waste return nitrates to the soil.

• Denitrification – bacteria return nitrogen back to the air.

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Why is phosphorus important?

• Phosphorus is found in nucleotides.• Nucleotides join together to form nucleic

acids• Nucleic acids control cell functions

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How does phosphorus move through the environment?

• Consumption – organisms eat each other and obtain phosphorus

• Decomposition and waste return it to the soil

• Plants acquire P from the soil• Weathering – rain breaks down rocks and

release the phosphorus they contain.