Transcript Carbon, Nitrogen, & Phosphorus

How Ecosystems Work
Carbon, Nitrogen &
Phosphorus Cycles
Section 2
How Ecosystems Work
Carbon Cycle
Carbon - in air, water,
and living organisms
 Exchange of carbon (C)
between nonliving
environment and
organisms
 Biogeochemical cycle –
chemical element or
molecule moves between
abiotic and biotic
components of Earth

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How Ecosystems Work
Carbon Cycle
C
- essential to
proteins, fats,
and
carbohydrates
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How Ecosystems Work
Carbon Cycle
 Producers
(plants)
convert CO2 into
carbohydrates
 Consumers
(animals) obtain C
from carbohydrates
in producers
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How Ecosystems Work
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Carbon Cycle
C
stored in organisms - released into
soil or air when organisms dies.
 These molecules can form coal, oil,
or natural gas (fossil fuels).
How Ecosystems Work
Section 2
Carbon Cycle
 During
cellular respiration, some C is
released into atmosphere (CO2).
How Ecosystems Work
Carbon Cycle
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How Ecosystems Work
Section 2
Human Affect on Carbon Cycle
 Humans
burn
fossil fuels,
releasing carbon
(CO2) into
atmosphere.
How Ecosystems Work
Section 2
Nitrogen Cycle
 Process
where nitrogen (N) circulates
among the atmosphere and living
things.
 N - in proteins
 N = 78% of atmospheric gasses
How Ecosystems Work
Section 2
Nitrogen Cycle
N
must be altered (fixed) before
organisms can use it.
 “Nitrogen-fixing” bacteria fix
atmospheric N into compounds that
can be used by other organisms.
How Ecosystems Work
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Nitrogen-Fixing Bacteria
 Live
within the roots of
legumes.
 Use carbohydrates
from legumes to
produce N containing
compounds.
 Excess “fixed” nitrogen
is released into soil.
How Ecosystems Work
Section 2
Decomposers and Nitrogen
Cycle
N
within bodies of organisms is
returned to N cycle when organisms
die.
 Decomposers break down decaying
organisms and wastes.
 Bacteria turn some N into gas, which
returns to atmosphere (completes
cycle).
How Ecosystems Work
Nitrogen Cycle
Section 2
How Ecosystems Work
Section 2
Phosphorus Cycle
 Movement
of phosphorus (P) in
different chemical forms from
environment to organisms and back
to environment.
How Ecosystems Work
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Phosphorus Cycle
P
- part of nucleotides
 Plants obtain P from soil and water
 Animals obtain P from other
organisms.
How Ecosystems Work
Section 2
Phosphorus Cycle
P
enters soil and water when rocks
erode.
– Some P dissolve as phosphate.
– Plants absorb phosphates.
 Some
P washes off land to ocean.
 Many phosphate salts are not soluble
in water
– accumulate as sediment.
How Ecosystems Work
Phosphorus Cycle
Section 2