Transcript 4.3 Carbon Cycle

Assessment State
Explain that energy enters and leaves
ecosystems, but nutrients must be
recycled
State that saprotrophic bacteria & fungi
recycle nutrients
Nutrient Cycles
Nutrient Cycles
• All the chemical substances that an organism needs to
sustain life are its nutrients.
• Every living organism needs nutrients to build tissues and
carry out essential life functions.
• Nutrients are passed between organisms and the
environment through biogeochemical cycles.
Nutrient Cycle
Nutrient Cycle
vs.
Food Chain
Food Chain
Decay & Decomposition
• All living organisms die –
the environment reclaims
the nutrients & returns
them to the ecosystem
Decay & Decomposition
• Nutrients from dead
organism are recycled by a
series of processes carried
out by other living
organisms.
Process of Decay:
1. Scavengers – Breakdown dead body to a
more manageable pieces
Process of Decay:
2. Decomposers (saprotrophic bacteria
and fungi)-- Break down what the
scavengers leave behind.
Decomposition and Carbon
Some decomposition of dead organisms is
similar to the process of respiration:
Dead organism + O2
CO2 + H2O
(Hydro-Carbons)
•
Decomposition is a process where the
carbon from the dead organism is broken
down by a microorganism using Oxygen &
a carbon dioxide and water is released.
Decomposition and Nitrogen
Other decomposition of dead organisms
breaks down proteins and releases
nitrogen into the soil in the form of
Ammonium (NH4)
Saprotrophic Microorganisms that do Decomposition
–
Fungus
–
Bacteria
– Other small organisms
The Carbon Cycle
CO2 in
Atmosphere
Photosynthesis
feeding
Volcanic
activity
Respiration
Decomposition
Human
activity
Erosion
CO2 in Ocean
Respiration
Uplift
Deposition
Photosynthesis
Fossil fuel
feeding
Deposition
Carbonate
Rocks
Online tutorial of global Carbon Cycle
http://www.sumanasinc.com/webcontent/an
imations/content/globalcarboncycle.html
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Assessment Statement:
Draw and Label a diagram of the carbon
cycle to show the processes involved.
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Carbon is found in one of four 'pools':
1.Biosphere
2.Oceans
3.Atmosphere
4.Sediments
• carbon is moved between these four pools
by a variety of biological, geochemical or
industrial processes.
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Nutrient Cycles
The Carbon Cycle
Carbon is a key ingredient of living tissue.
Nutrient Cycles
The Carbon Cycle
Six Biological processes take up and release
carbon such as
1.
2.
3.
4.
5.
6.
photosynthesis,
Respiration
Decomposition
Death
Excretion
Feeding
All living things Respire
Carbon Dioxide from Respiration
Write equation:
All living things Respire
Carbon Dioxide from Respiration
Write equation:
Photosynthesis/ Carbon fixation By
AUTROTROPHS
Plant Material
Photosynthesis Equation:
Photosynthesis/ Carbon fixation By
AUTROTROPHS
Plant Material
Photosynthesis Equation:
Decomposition and Carbon
Decomposition
Some decomposition of dead organisms is similar to
the process of respiration:
Dead organism + O2
CO2 + H2O
Excretion Process
•Organisms put
carbon back in the
soil or water via
waste-- Excretion
Nutrient Cycles
Death Process
When organisms die, decomposers return carbon to the
soil and atmosphere (CO2)
Feeding – animals,
bacteria, fungi – all
heterotrophs get carbon
through eating it.
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Geochemcial Process
Geochemical processes, such as the
–burial and decomposition of dead organisms
and their conversion under pressure into coal and
petroleum (fossil fuels), store carbon underground.
Carbon sources: Fossil Fuels
Coal Formation – Deposition of
Ancient fossilized plants
Forms Of Carbon
Coal (fossil fuels)
Human Activities
Human activities, such as mining, cutting and
burning forests, and burning fossil fuels, release
carbon dioxide into the atmosphere.
Forms of Carbon
Sources of Carbon Dioxide
Burning Fossil Fuel (example: Cars)
Production of Methane (CH4) by Methanogenic
archeans
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Production of Methane
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Production of Methane
Methane is oxidized into Carbon Dioxide and water in
the atmosphere.
Methane molecules will persist in the atmosphere for
about 12 years and then they are naturally oxidized
by monatmoic oxygen
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Peat Formation
Peat formation occurs
• when soils become water logged/ saturated and
anaerobic (no oxygen for decomposition or
respiration)
• Saprotrophs cannot survive without oxygen
• Dead organic matter can not be decomposed in
these anaerobic conditions and so it accumulates
in the form of compressed dark brown acidic
material called peat
• Many places on earth are covered with peat. So
large amounts of carbon is locked up in peat.
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Limestone –Calcium
Carbonate Rock
• Rock formed from reefbuilding coral animals and
molluscs.
• When these animals die
their calcium carbonate
skeleton accumulate and
over long periods of time are
compressed into rocks.
• Large amounts of carbon
are locked up in these rocks.
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Assignment:
Draw and Label a diagram of the carbon cycle to show the processes
involved. Be sure to include the below processes:
•
Cellular Respiration
•
Decomposition
•
Excretion
•
Feeding
•
Combustion
•
Photosynthesis/ carbon fixation
•
Death
•
Methane production
•
Peat Formation
•
Limestone formation
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Assessment Statement
5.2.3 Explain the relationship between rises in
concentration of atmospheric carbon dioxide using
historical records.
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Carbon Dioxide Levels (ppm)
Yearly changes in the Carbon Dioxide: Why do the
carbon dioxide levels go up & down in our
atmosphere over the course of a year?
winter
Spring
time
Seasonal Changes in Carbon Dioxide
FALL/ WINTER
SPRING/ SUMMER
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Carbon Dioxide Levels (ppm)
Changes in Carbon Dioxide in our Atmosphere in the
last 100+ years.
Why has carbon dioxide increased?
Nutrient Cycles
CO2 in
Atmosphere
Photosynthesis
feeding
Volcanic
activity
Respiration
Decomposition
Human
activity
Erosion
CO2 in Ocean
Respiration
Uplift
Deposition
Photosynthesis
Fossil fuel
feeding
Deposition
Carbonate
Rocks
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Assessment Statement
5.2.3 Explain the relationship in the rises in
greenhouse gases and the enhanced
greenhouse effect.
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The greenhouse effect
1.Solar radiation travels to the surface of the earth.
2.This radiation is absorbed by the earth’s surface.
3.Earth’s surface emits (releases) radiation in the form
of Infrared radiation(also called heat)
4.This infrared radiation (heat) tries to leave earth but
gets trapped by the greenhouse gases.
5.The heat is trapped close to earth’s surface and thus,
keeps the planet warm.
Types of Solar Radiation
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Who are greenhouse gases?
Methane
Carbon Dioxide
Nitrogen Oxides
Sulfur Oxides
The Greenhouse Effect Explained
a) Short wave solar radiation (light)
b) light penetrates the atmosphere and passes
through the molecules of the atmosphere
c) Absorption by the ground and conversion to
long wave infrared radiation (heat)
d)This warms the planet
e) Some infrared is lost to space as heat
f) Atmospheric gases particularly, carbon
dioxide, methane and nitrogen oxides.
g) Greenhouse gases absorb infra-red radiation
and scatter this rather than letting it escape to
space. In effect this traps the heat energy.
h) Some light reflects off the outer surface of
the atmosphere and never enters
Note that if this 'greenhouse' effect did not exist the
average global temperature would be -17 C.
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Green House Effect on other planets in our
solar system
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Enhanced Greenhouse Effect
• Enhanced greenhouse effect is the
concern that the activities of human's may
be increasing the levels of carbon dioxide
and other 'greenhouse gases’ in the
atmosphere.
• That this may lead to increased global
temperatures and climate change
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The enhanced greenhouse effect.
• Increase in carbon dioxide and other greenhouse gases
(methane, oxides of nitrogen) will increase the particles in
the greenhouse gas layer
• Therefore more infra-red will be absorbed, scattered and
retained as heat.
• The average global temperatures will rise. Some models
suggest as much as 40C in the next 50 years.
• An enhanced greenhouse effect is predicted to cause
global climate changes. This is often referred to as global
warming but whilst the average global temperatures may
rise the local effects may vary widely.
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Online tutorial of greenhouse effect:
http://earthguide.ucsd.edu/earthguide/diagr
ams/greenhouse/
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Assessment Statement
5.2.4 Outline the precautionary principle.
'If the effects of human-induced change would
be large, perhaps catastrophic, those
responsible for the change must prove that it
will not do harm before proceeding
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Assessment Statement
5.2.5. The precautionary principle and the
greenhouse effect.
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5.2.5. The precautionary principle and the
greenhouse effect
• The 'Precautionary principle' suggests that the
obligation actually falls on those accused of
causing climate change (or enhanced greenhouse
effect) to show that their actions are not causing
damage.
If we wait until it is proven that humans are causing
climate change it will be too late to reduce the
impacts.
Is it better to respond now as a precaution even if in
the long term it turns out that the case cannot be
made.
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• The Precautionary principle reverses the argument of the
'Burden of Proof'.
• The 'Burden of proof' principle in which (in context) it is up to those
who claim that there is climate change( due to human causes) to
prove that this is the case. That there is no need to respond to
request for action to reduce human impact until that case has been
proven.
• The precautionary principle argues that those responsible for an
effect (global warning, climate change, enhanced greenhouse
effect) have the obligation to show that what they are doing has
causes no harm.
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In context of the enhanced greenhouse effect then:
• Skeptic approach: The 'burden of proof' lies with those
claiming that harm is caused by those responsible for
the enhanced greenhouse effect to provide evidence
that this is in fact the case. In other words, the
environmentalist need to provide conclusive evidence
that the actions of the 'polluters' are causing harm to
the environment.
• Precautionary Principle Approach: Those allegedly
responsible for causing the effects of the enhanced
greenhouse effect are required to demonstrate that
their action do not cause harm. This responsibility
would then fall on a wide spectrum or Nation
Government, Industries, Communities and individuals
to demonstrate that their actions cause no harm.
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