Transcript 4.3 Carbon Fluxes PPT

Carbon: Transformations in Matter and Energy
Environmental Literacy Project
Michigan State University
Human Energy Systems Unit
Activity 4.3: Carbon Fluxes
The Keeling Curve
Explaining the seasonal cycle
2
The Carbon Movement Question
How are carbon atoms cycling among pools?
How are the pools getting larger or smaller?
What makes carbon move from one pool to another?
3
Question:
During
photosynthesis
which way does
carbon move?
Which pool(s)
increase and
decrease when
photosynthesis
happens?
Atmosphere
CO2
Soil
organic carbon
Biomass
organic carbon
Fossil Fuels
organic carbon
4
Question:
During cellular
respiration (in
plants, animals and
decomposers)
which way does
carbon move?
Which pool(s)
increase and
decrease when
cellular respiration
happens?
Atmosphere
CO2
Soil
organic carbon
Biomass
organic carbon
Fossil Fuels
organic carbon
5
Carbon pools
change size over
time
The amount of carbon
that moves per unit of
time is called a “flux”.
Biomass
organic carbon
Photosynthesis
Cellular Respiration
Cellular Respiration
Different amounts of
carbon move between
the atmosphere and
the biomass or soil
pools in the summer
versus in the winter.
Atmosphere
CO2
Soil
organic carbon
Fossil Fuels
organic carbon
6
Carbon moving from pool to
another relates to energy
• Why does photosynthesis happen in
plants?
• Why does cellular respiration happen in
the biomass pool?
• Why does cellular respiration happen in
the soil pool?
• How are these things connected to
energy?
7
Energy enters the biomass pool
from the sun
How does energy enter the biomass pool?
(Remember our third rule: Energy flows! Energy
can never be created or destroyed. It has to come
from somewhere).
Through the process of
photosynthesis, plants absorb
sunlight energy and sequester
it in C-C and C-H bonds of
glucose molecules. This
energy may be stored in the
plant’s body (and might even
be eaten by an animal). This is
how energy enters the
biomass pool.
8
Energy flows out of the biomass pool
How does chemical energy leave the biomass pool?
Plants, animals and
decomposers do cellular
respiration for all of their life
processes. During cellular
respiration, organic molecules
like sugar are broken apart.
High energy bonds in sugar (CC and C-H) are replaced by low
energy bonds (C-O and H-O)
and the chemical energy is
released. This energy can be
transformed into:
work or motion energy and
eventually to
heat radiated into space
9
Where does the energy go?
When the energy leaves the biomass pool and enters the
atmosphere pool, what happens to it? (Remember, energy can
never be created or destroyed. It has to go somewhere).
Heat energy is lost from the
biomass pool (and eventually
radiates into outer space).
Some of this heat energy is
trapped in greenhouse gases
and remains in the atmosphere.
Most of this heat radiates back
into outer space.
As greenhouse gases increase,
more of this heat is trapped in
the atmosphere, causing the
global temperatures to rise.
10
Example scenario card
Round 1: Decide as a group what will happen to the
organic and inorganic pools of carbon according to
the scenario below:
• It is summer in the northern hemisphere and annual
flowers begin to grow.
• Winter comes and the annual plants die and are
digested by decomposers.
Round 2: Explain how energy is transformed in the
scenarios above.
11