Nutrient Recycling in Ecosystems
1.4.8 Nutrient Recycling
2
Need to know
Define the term: nutrient recycling by
organisms.
1.
Outline and draw the Carbon Cycle.
2.
Outline and draw the Nitrogen Cycle.
3
Nutrient Recycling
(1/3)
There is a
limited
amount of
nutrients
on earth
e.g. you are probably aware of the water
cycle – where water is constantly being
recycled
in nature. There are similar cycles
for all nutrients.
When plants and animals die, their nutrient
content is
not wasted
.
Bacteria and fungi decompose the remains
and release the nutrients back into the
abiotic environment (i.e. into the soil,
nearby water and air).
4
Nutrient Recycling
(2/3)
These nutrients are then taken up by other
plants and used to make new organic
material.
This material is passed on down the food
chains and is reused by all the chain
members.
When death occurs for these members, the
nutrients are again returned to the abiotic
environment and the cycling of nutrients
continues in this circular way.
5
Recycling nutrients within an ecosystem
Organic Material
in Consumers
Breakdown of Organic
Molecules in
Decomposers
Organic Material in
Producers
Abiotic
Environment
Soil and Water
Photosynthesis and
Chemosynthesis
Feeding
6
Nutrient Recycling
(3/3)
This ensures that there is no real longterm
drain on the Earth’s nutrients, despite
millions of years of plant and animal
activity.
7
In summary
Nutrient recycling is the way in which
elements are continuously being broken
down and/or exchanged for reuse between
the living and non-living components of an
ecosystem.
8
Carbon Cycle
Carbon
forms part of all organic nutrients –
carbohydrates, fats and proteins.
Carbon dioxide is
removed
from the
environment by
photosynthesis
in plants,
and
under certain conditions, over long
periods of time, some of these plants may
form
fossil fuels
such as coal, oil, peat and
natural gas
.
9
Carbon Cycle
Carbon dioxide is
returned
to the environment
by:
1.
Respiration
in plants, animals & micro-
organisms.
2.
Decay
caused by micro-organisms.
3.
Combustion
i.e. burning fossil fuels
10
The Carbon Cycle
(1/3)
11
Summary of Carbon Cycle
Click on the link below to see a summary of
the Carbon Cycle
The Carbon Cycle
12
Learning check
What is meant by nutrient recycling?
Nutrient recycling is the way in which
elements are continuously being broken
down and/or exchanged for reuse between
the living and non-living components of an
ecosystem.
13
Learning check
What process(es) remove Carbon dioxide
from the atmosphere?
Photosynthesis
What process(es) add Carbon dioxide to the
atmosphere?
Respiration
Decay
Combustion
14
The Nitrogen Cycle
All organisms need
nitrogen
for protein, DNA
& RNA manufacture
78% of the Earth’s atmosphere is nitrogen
gas, but it cannot be used in this form by
plants and animals.
Nitrogen gas must first be ‘
fixed’
, i.e. changed
to a suitable form (ammonia or nitrate)
before it can be used.
15
Nitrogen Fixation
♣
Nitrogen-fixing bacteria
in the soil convert
N
2
gas in the air into ammonia (NH
3
). This
accounts for the majority of all N
2
fixation.
♣
Lightening storms
and
fuel burning in car
engines
produce nitrates, which are washed
by rain into the soil water.
♣
Nitrates
are absorbed by plant roots and
converted to plant protein.
16
The Nitrogen Cycle
Plant proteins are passed along food chains
to become animal protein.
When organisms die, their proteins are
converted to ammonia by bacterial
decomposition.
Nitrifying bacteria
in the soil then convert
ammonia (NH
3
) into nitrites (NO
2
2
_
) then
into nitrates (NO
3
_
).
Nitrates can be absorbed by other plants to
continue the cycle.
17
The Nitrogen Cycle
Denitrifying bacteria
convert soil nitrates
into N
2
gas.
This is a
loss
of N
2
from the cycle.
Only happens in anaerobic conditions (when O
2
levels are low) – due to flooding or accumulation
of sewage.
Nitrate also
enters
the cycle through the
addition of nitrogen rich fertilisers to the
soil – made industrially from nitrogen gas.
18
The Nitrogen Cycle
19
Summary of Nitrogen Cycle
Click on the link below to see a summary of
the Nitrogen Cycle
The nitrogen cycle
20
Summary of Nitrogen Cycle
1.
Nitrogen Fixation &
Lightning
2.
Absorbed by roots and used
by plants – Assimulation
3.
Animal feeding, digestion &
assimulation
4.
Excretion: urea
Ammonia
5.
Death & decomposition
– putrefying bacteria
6.
Nitrification: NH
3
NO
2
7.
Nitrification: NO
2
NO
3
8.
Denitrification: NO
3
NO
2
N
21
Learning check
Nitrogen gas must be ‘fixed’ – what does this
mean?
Changed to a suitable form (ammonia or nitrate)
before it can be used.
In what form is nitrogen absorbed by plants?
Nitrate
22
Learning check
What is nitrification?
The conversion of ammonia (NH
3
) into nitrites
(NO
2
2
_
) then into nitrates (NO
3
_
).
What do denitrifying bacteria do?
They convert soil nitrates (NO
3
_
) into N
2
gas.
23
END
Nutrient recycling in ecosystems involves the continuous breakdown and exchange of elements between living and non-living components, ensuring sustainability and no long-term drain on Earth's nutrients. This process includes decomposition of organic material by bacteria and fungi, uptake of nutrients by plants, passing through food chains, and eventual return to the abiotic environment for reuse. Similar cycles like the carbon cycle play a crucial role in maintaining nutrient balance and supporting life on Earth.
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Presentation Transcript
Need to know Define the term: nutrient recycling by organisms. 1. Outline and draw the Carbon Cycle. 2. Outline and draw the Nitrogen Cycle. 2
Nutrient Recycling (1/3) There is a limited amount of nutrients on earth e.g. you are probably aware of the water cycle where water is constantly being recycled in nature. There are similar cycles for all nutrients. When plants and animals die, their nutrient content is not wasted. Bacteria and fungi decompose the remains and release the nutrients back into the abiotic environment (i.e. into the soil, nearby water and air). 3
Nutrient Recycling (2/3) These nutrients are then taken up by other plants and used to make new organic material. This material is passed on down the food chains and is reused by all the chain members. When death occurs for these members, the nutrients are again returned to the abiotic environment and the cycling of nutrients continues in this circular way. 4
Recycling nutrients within an ecosystem Organic Material in Consumers Feeding Breakdown of Organic Molecules in Decomposers Organic Material in Producers Photosynthesis and Chemosynthesis Abiotic Environment Soil and Water 5
Nutrient Recycling (3/3) This ensures that there is no real longterm drain on the Earth s nutrients, despite millions of years of plant and animal activity. 6
In summary Nutrient recycling is the way in which elements are continuously being broken down and/or exchanged for reuse between the living and non-living components of an ecosystem. 7
Carbon Cycle Carbon forms part of all organic nutrients carbohydrates, fats and proteins. Carbon dioxide is removed from the environment by photosynthesis in plants, and under certain conditions, over long periods of time, some of these plants may form fossil fuels such as coal, oil, peat and natural gas. 8
Carbon Cycle Carbon dioxide is returned to the environment by: 1. Respiration in plants, animals & micro- organisms. 2. Decay caused by micro-organisms. 3. Combustion i.e. burning fossil fuels 9
Summary of Carbon Cycle Click on the link below to see a summary of the Carbon Cycle The Carbon Cycle 11
Learning check What is meant by nutrient recycling? Nutrient recycling is the way in which elements are continuously being broken down and/or exchanged for reuse between the living and non-living components of an ecosystem. 12
Learning check What process(es) remove Carbon dioxide from the atmosphere? Photosynthesis What process(es) add Carbon dioxide to the atmosphere? Respiration Decay Combustion 13
The Nitrogen Cycle All organisms need nitrogen for protein, DNA & RNA manufacture 78% of the Earth s atmosphere is nitrogen gas, but it cannot be used in this form by plants and animals. Nitrogen gas must first be fixed , i.e. changed to a suitable form (ammonia or nitrate) before it can be used. 14
Nitrogen Fixation Nitrogen-fixing bacteria in the soil convert N2 gas in the air into ammonia (NH3). This accounts for the majority of all N2 fixation. Lightening storms and fuel burning in car engines produce nitrates, which are washed by rain into the soil water. Nitrates are absorbed by plant roots and converted to plant protein. 15
The Nitrogen Cycle Plant proteins are passed along food chains to become animal protein. When organisms die, their proteins are converted to ammonia by bacterial decomposition. Nitrifying bacteria in the soil then convert ammonia (NH3) into nitrites (NO2 into nitrates (NO3 Nitrates can be absorbed by other plants to continue the cycle. 2 _) then _). 16
The Nitrogen Cycle Denitrifying bacteria convert soil nitrates into N2 gas. This is a loss of N2 from the cycle. Only happens in anaerobic conditions (when O2 levels are low) due to flooding or accumulation of sewage. Nitrate also enters the cycle through the addition of nitrogen rich fertilisers to the soil made industrially from nitrogen gas. 17
Summary of Nitrogen Cycle Click on the link below to see a summary of the Nitrogen Cycle The nitrogen cycle 19
Summary of Nitrogen Cycle Nitrogen in Air NO2 Nitrite Ammonia NH3 6 7 4 1 8 5 5 Nitrate in Soil NO3 Animal Protein 2 Plant Protein 3 1. Nitrogen Fixation & Lightning 2. Absorbed by roots and used by plants Assimulation 3. Animal feeding, digestion & assimulation 4. Excretion: urea Ammonia 5. Death & decomposition putrefying bacteria 6. Nitrification: NH3 NO2 7. Nitrification: NO2 NO3 8. Denitrification: NO3 NO2 N 20
Learning check Nitrogen gas must be fixed what does this mean? Changed to a suitable form (ammonia or nitrate) before it can be used. In what form is nitrogen absorbed by plants? Nitrate 21
Learning check What is nitrification? The conversion of ammonia (NH3) into nitrites (NO2 2 _) then into nitrates (NO3 _). What do denitrifying bacteria do? They convert soil nitrates (NO3 _) into N2 gas. 22
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