SNC1D - Sustainable Ecosystems
Nutrient Cycles
Pearson p 18-19, 22-27
The biosphere is the part of the planet where life
exists, including the air, soil and water. The three
main components of the biosphere are
1. Atmosphere – layer of gases surrounding the
Earth
2. Lithosphere – the solid layer at the surface of the
Earth
3. Hydrosphere – all the water on Earth
For organisms to grow they require nutrients from
some part of the biosphere. Nutrients from food and
water provide energy for an organism to live, grow
new cells and repair cells. Nutrients are made of
elements like oxygen, hydrogen, carbon and
nitrogen.
Nutrients cycle from biotic to abiotic forms. Living
plants and animals are biotic reservoirs or storage
sites for the nutrient elements. When the plants and
animals die, the biotic molecules are decomposed so
the nutrients can be reused. The abiotic nutrient
reservoirs are water, air and soil.
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The water cycle moves the elements hydrogen and
oxygen. Two other nutrient cycles are the carbon
cycle and the nitrogen cycle.
SNC1D - Sustainable Ecosystems
1) The Carbon Cycle
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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.
The carbon reservoirs are the atmosphere and the
oceans which both store carbon dioxide. Also, living
organisms that have carbon in their bodies, and
carbon from dead plants and animals forms fossil
fuels.
2) The Nitrogen Cycle
SNC1D - Sustainable Ecosystems
Abiotic nitrogen gas is part of air. Special nitrogen
fixing bacteria in the roots of beans(legumes) can
convert nitrogen gas to ammonia. Then nitrifying
bacteria change ammonia to nitrites and nitrates.
Nitrates are absorbed by plant roots and used to
make proteins. When animals eat plants they
absorb nitrates to make proteins. When dead plants
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and animals decompose the proteins are broken
down by decomposers to be reused.
Different bacteria can also convert nitrates back into
atmospheric nitrogen.
SNC1D - Sustainable Ecosystems
Nutrient Cycles
The biosphere is the part of the planet where life exists, including the air, soil and water. The three main
components of the biosphere are
1. __________________________ – layer of gases surrounding the Earth
2. __________________________ – the solid layer at the surface of the Earth
3. __________________________ – all the water on Earth
For organisms to grow they require nutrients from some part of the biosphere. Nutrients from food and
water ______________________________________________________________________________.
Nutrients are made of ____________________________ like oxygen, hydrogen, carbon and nitrogen.
Nutrients cycle from ___________________ to ____________________________ forms. Living plants
and animals are biotic reservoirs or
___________________________________________________________. When the plants and animals
die, the biotic molecules are _____________________________________________________________.
The abiotic nutrient reservoirs are ________________________________________________.
The water cycle moves the elements __________________________ and ________________________.
Two other nutrient cycles are the carbon cycle and the nitrogen cycle.
1) The Carbon Cycle
In the carbon cycle
_________________
_________________
___ is the only
process to change
_________________
_____ carbon into
_________________
______ carbon for
plants and animals.
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_________________________________________, ____________________ and __________________
all turn biotic carbon into abiotic carbon dioxide. The carbon reservoirs are the atmosphere and the
oceans which ____________________________________. Also, living organisms have carbon in their
________________________, and carbon from dead plants and animals _________________________.
2) The Nitrogen Cycle
Abiotic nitrogen gas is part of air. Special __________________________________________ in the
roots of ____________________________can convert __________________________. Then
______________________ bacteria change ammonia to nitrites and nitrates. Nitrates are
_____________ by plant roots and used to______________________________. When animals eat
plants they absorb nitrates to make proteins. When dead plants and animals _________
______________________are broken down by decomposers to be reused. Different bacteria can also
convert nitrates back into atmospheric nitrogen.
SNC1D - Sustainable Ecosystems
Nutrient Cycles Worksheet
Name: _______________________
1.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.
2.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.
Bonus – Water Cycle questions
3.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?