SNC1D - Sustainable Ecosystems
Nutrient Cycles
(Nelson p62-69)
For organisms to grow they require elements like oxygen,
carbon, hydrogen and nitrogen. These elements include abiotic
forms and biotic forms.
Abiotic forms of the elements include water (H2O), carbon
dioxide (CO2), oxygen gas (O2) and nitrogen gas (N2). Abiotic
forms of elements are found in soil, water or the atmosphere.
Biotic forms of the elements are always found in living plants
and animals in cells. Molecules like glucose which are found
in cells contain carbon, hydrogen oxygen in biotic forms.
Elements cycle from the biotic to abiotic form. When the plants
and animals die, the biotic molecules are decomposed so the
nutrients can be reused.
SNC1D - Sustainable Ecosystems
1) The Carbon Cycle
In the carbon cycle photosynthesis is the only process to change
abiotic carbon into biotic carbon for plants and animals.
Cellular respiration, burning and decomposition all turn biotic
carbon into abiotic carbon dioxide.
SNC1D - Sustainable Ecosystems
2) The Nitrogen Cycle
Abiotic nitrogen gas is part of air. Special nitrogen fixing
bacteria in the roots of beans can convert nitrogen gas to biotic
nitrate. Nitrates are absorbed by plant roots and used to make
proteins. When animals eat plants they absorb nitrates to make
proteins. When dead plants and animals decompose the
proteins go back to be reused
SNC1D - Sustainable Ecosystems
3) The Phosphorus Cycle
All organisms need abiotic phosphorus to make biotic
phosphates for DNA and other cell molecules. The short
time cycle of phosphorus occurs when organisms die, are
decomposed and the phosphorus is reabsorbed into an
organism.
SNC1D - Sustainable Ecosystems
Most phosphorus is stored in abiotic rocks and erosion can
make this phosphorus available for organisms to absorb in the
phosphorus long cycle time.
SNC1D - Sustainable Ecosystems
Nutrient Cycles Worksheet
Name: _______________________
Text Nelson p 62 - 68
1. Use the lecture note diagrams to complete the following chart showing biotic and abiotic forms of
carbon, water and nitrogen.
Element
carbon
Biotic Forms
Abiotic Forms
nitrogen
water
2.a)
Name and describe the process that takes carbon from the atmosphere and stores carbon in a biotic
form.
b)
Name and describe the two processes that take carbon from the biotic forms and release carbon in
an abiotic form.
c)
Name three foods you eat that are carbohydrates and provide your body with a lot of carbon.
3.a)
Describe the process that takes nitrogen from the atmosphere and stores nitrogen in the biotic form
of proteins.
b)
How is the nitrogen in proteins released to recycle?
c)
Is the same kind of bacteria doing both the nitrifying and denitrifying process? Guess.
d)
Name three foods you eat that contain a lot of nitrogen in proteins.
SNC1D - Sustainable Ecosystems
4.a)
Using the phosphate cycle diagram, list all the abiotic locations of phosphates.
b)
Using the phosphate cycle diagram, list all the biotic locations of phosphates.
c)
Why do some of the lines on the diagram have dots? Explain.
d)
What is one food you eat that contains phosphates?
Bonus – Water Cycle questions
5.a)
How do plants get water into their cells?
b)
What are two ways animals get water into their bodies?
c)
Describe two ways that animals release water to go back into the atmosphere.
d)
How do plants release water to go back into the atmosphere?