Transcript The Carbon and Oxygen Cycles

The Cycles
Presented by
Mr. Rainbeau
III. The Cycles
A. The water cycle is the
repeated movement of water
between the Earth’s atmosphere,
surface and living things
1. Evaporation
– water
changes from
a liquid to a
gas
2. Transpiration
– how water
evaporates from
leaves
3. Respiration
- breathing
4. Condensation
- the process by
which water
vapor in the air
is changed into
liquid water
(clouds)
5. Precipitation
- water
released from
clouds in the
form of rain,
snow, or hail
6. Runoffprecipitation
falls on the
land, flows over
land (runoff),
and runs into
rivers, which
then empty into
the oceans
Water cycles through not only
abiotic, but biotic factors as well:
–Transpiration
–Perspiration
–Breathing
–Urination
B. The Carbon and
Oxygen Cycles
B. The carbon and oxygen cycles
are the repeated movements of
C and O through an ecosystem
1. CO2 in the
air/water is
used by plants,
algae, and
bacteria for
photosynthesis
2. Carbon atoms return to the
pool of CO2 in the air in one
of three ways
a) Respiration –
nearly all
organisms
engage in cellular
respiration and
CO2 is the
byproduct
b) Combustion – Carbon returns
to the atmosphere through
burning.
1) Burning of fossil
fuels (Remains of
organisms that
became buried
gradually
transformed by
heat and pressure
into oil and coal)
Non-renewable!
c) Erosion – shells of dead organisms
form limestone and as the limestone
erodes the carbon becomes
available
3. Carbon is stored in limestone, fossil
fuels, and biomass in the ecosystem
C. Nitrogen Cycle is the pathway by which
N moves through an ecosystem
1. Nitrogen is needed for:
a) Proteins b) DNA & RNA
c) ATP
2. Air we breathe is 78% nitrogen – but
we cannot use this form
3. Four processes of the nitrogen cycle:
a) Nitrogen fixation - the process
that converts N2 in the air into
usable nitrogen compounds
1) nitrogen fixing bacteria in soil and
roots convert N2 into NH3
(ammonium ions)
b) Nitrification - ammonium ions are
changed into nitrates (done by
nitrifying bacteria)
c) Ammonification breaking down of
Nitrogen
compounds in
remains of dead
organisms
(performed by
decomposers)
d) Denitrification conversion of
ammonia or
nitrates into nitrogen gas. (by
Denitrifying bacteria)
• take nitrogen compounds in
the soil and convert it into free
nitrogen and returned it to the
atmosphere