Transcript Nitrifying bacteria Nitrifying bacteria Nitrogen fixing bacteria De

Nutrient Cycles
The water cycle, nitrogen cycle
and carbon cycle
The Water Cycle
The Nitrogen Cycle
Nitrogen
• All organisms need nitrogen to make
proteins.
• Nitrogen gas makes up 78% of our air but
it cannot be used directly by most
organisms.
• Organisms get nitrogen from substances
that contain nitrogen. Examples?
De-nitrifying
bacteria
Nitrogen fixing
bacteria
Nitrifying bacteria
Nitrifying bacteria
Nitrogen-fixation
• Nitrogen-fixing bacteria can convert
nitrogen gas into ammonia.
• Without these bacteria the nitrogen cycle
would stop.
• The only other natural nitrogen-fixing
process is lightning which accounts for
about 1% .
Nitrogen-fixing Bacteria
• occur in nodules on the roots of legumes
such as peas, beans, and alfalfa. These
bacteria provide usable nitrogen to the
plant.
• live freely in soil and water but the
ammonia they create cannot be used
directly by most plants.
• Soya beans
• Nodules on roots
contain nitrogen-fixing
bacteria
Photo Credit:
Jennifer Dean
Lightning naturally fixes nitrogen in
the atmosphere and changes it into
ammonia.
Ammonia in soil
• Nitrifying bacteria
fixing
convert ammonia Nitrogen
bacteria
to nitrites and then
nitrates which plants
can absorb through
their roots.
De-nitrifying
bacteria
Nitrifying bacteria
Nitrifying bacteria
Animals get the nitrogen they need
by eating plants or animals.
• When nitrogen is digested, ammonia is
formed and this toxic product is removed
through the animal’s waste and returned to
the soil.
• Bacteria and fungi in the soil break down
the ammonia into nitrites and nitrates
where they are released into the soil to be
used by plants.
Returning Nitrogen to the Air
• Denitrifying bacteria in the soil convert
nitrates back into nitrogen gas.
Nitrogen
fixing
bacteria
Denitrifying
bacteria
Nitrifying
bacteria
Nitrifying
bacteria
The
Nitrogen
Cycle
The Carbon Cycle
The Carbon Cycle
• All living things contain carbon.
• Carbon dioxide makes up 0.04%
of the gases in the atmosphere.
• Carbon dioxide provides all of the
carbon that plants need to grow.
• Carbon reservoirs include:
– all the forests in the world,
– the oceans where CO2 is dissolved in the
water
– and fossil fuel deposits of coal and oil.
• Photosynthesis and respiration move
carbon between the various reservoirs and
provides the method for the flow of energy
through an ecosystem.
Photosynthesis and Respiration
Photosynthesis
• Process plants use to capture the sun’s
energy and convert it into another form:
• Food!
• Plants use chlorophyll to capture the sun’s
energy.
CO2 + water
Sunlight energy
glucose + O2
Respiration
• The O2 produced by the plants provides
the O2 we need to live!
• The glucose made during photosynthesis
is used by the plant to live and grow.
• The energy from the glucose is released
during cellular respiration.
glucose + O2
CO2 + water + energy
Photosynthesis vs. Respiration
CO2 + H2O + sunlight
C6H12O6 + O2
C6H12O6 + O2
CO2 + H2O + energy