Transcript Carbon and nitrogen cycles

Food Production and
the Environment
The Carbon Cycle
Carbon dioxide
in the air
Carbon dioxide
in the air
Green plants use
carbon dioxide to
make their food
Carbon dioxide
in the air
Green plants use
carbon dioxide to
make their food
Green plants are
eaten by animals
Carbon dioxide
in the air
respiration
Green plants use
carbon dioxide to
make their food
Green plants are
eaten by animals
carbon dioxide
in the air
respiration
green plants use
carbon dioxide to
make their food
green plants are
eaten by animals
dead remains of plants
and animals
carbon dioxide
in the air
respiration
green plants use
carbon dioxide to
make their food
green plants are
eaten by animals
dead remains of plants
and animals
decay by fungi
and bacteria
Decay
 Fungi and bacteria
are responsible for
the decay of dead
organisms.
Decay

In order to be able
to carry out decay,
fungi and bacteria
need:
1. Oxygen
2. Moisture
3. The correct
temperature
The Nitrogen Cycle
nitrogen in
the air
nitrogen in
the air
fertilizers
fertilizers
nitrogen in
the air
fertilizers
fertilizers
waste
substances
e.g. faeces
nitrogen in
the air
lightning
fertilizers
fertilizers
waste
substances
e.g. faeces
nitrogen in
the air
lightning
fertilizers
fertilizers
waste
substances
e.g. faeces
Nitrogen-fixing
bacteria in the soil
nitrogen in
the air
lightning
fertilizers
fertilizers
waste
substances
e.g. faeces
Nitrogen-fixing
bacteria in the soil
Nitrogen-fixing
bacteria in the root
nodules of clover
nitrogen in
the air
lightning
fertilizers
fertilizers
waste
substances
e.g. faeces
Nitrogen-fixing
bacteria in the soil
dead remains of
plants and
animals
Nitrogen-fixing
bacteria in the root
nodules of clover
nitrogen in
the air
lightning
fertilizers
fertilizers
waste
substances
e.g. faeces
Nitrogen-fixing
bacteria in the soil
Nitrogen-fixing
bacteria in the root
nodules of clover
dead remains of
plants and
animals
nitrates in the
soil
lightning
fertilizers
fertilizers
waste
substances
e.g. faeces
Nitrogen-fixing
bacteria in the soil
Nitrogen-fixing
bacteria in the root
nodules of clover
dead remains of
plants and
animals
nitrates in the
soil
denitrifying
bacteria in the soil
break down nitrates
The nitrogen cycle
 Living things need
nitrogen to make
protein.
 They can not use the
nitrogen in the air
 The nitrogen in the
air must be changed
to nitrates before
plants can use it.
The nitrogen cycle
 Animals get their
nitrogen by eating
plants.
The nitrogen cycle
 The roots of some
plants (e.g. clover,
pea & beans) have
swellings called root
nodules on them.
 Nitrogen-fixing
bacteria living in
these nodules
change nitrogen in
the air into nitrates.
The nitrogen cycle
 The nitrogen-fixing
bacteria are essential
to maintain the
fertility of the soil.
 Without them food
yields would rapidly
fall.