Transcript the carbon cycle

Ch. 13-4:
The Atmosphere
Characteristics of the Atmosphere
• It is a blanket of moisture-filled air that surrounds the
earth
• It consists 78% nitrogen, 21% oxygen, 1% other gases
(argon, carbon dioxide and water)
• It has ozone in its upper layers which absorb harmful UV
rays from the sun
• It protects us from meteors (they vaporize due to the
friction with the atmosphere)
• It keeps the earth warm enough for us to live
Layers of Atmosphere
Temperature Gradient
• A change in temperature over a distance
****In the troposphere the temperature gradient
is -6.5°/km in altitude
Example: What is the temperature at the top of an
8000 m mountain if the temperature is 18°C at
the foot of the mountain?
Layers Again….
Layers in Order…(starting from the
Earth upwards)
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•
•
•
•
1. Troposphere – up approx 12 km
Closest to the Earth’s surface
Where all weather takes place
Air is in constant motion with both vertical and horizontal currents
Pressure decreases as altitude increases
Has very small amounts of ozone
2. Tropopause
•
Contains more ozone than troposphere
•
Is warmer than the troposphere because it absorbs UV rays from
the sun
3.STRATOSPHERE
• 12-50 km above the
Earth’s surface
• Higher levels of ozone
than any other layer
4.MESOSPHERE
• Temperatures are very
low here
• 50 to 80 km above the
earth
• Very low density
• Meteors from space
usually burn up in this
layer due to air friction
• Temperatures are very
low here
5.Thermosphere
AKA –Ionosphere
• 80 km to 500 km from
Earth’s surface
• Fewest air molecules
• Also called ionosphere b/c
the Sun’s radiation causes
particles to become
electrically charged ions
• The Northern and Southern
lights (aurora borealis) are
produced by these ions
• These charged particles also
reflect radio signals so they
can travel around the World
6. Exosphere
• Outer limits! SPACE
• The thin, outermost layer
• Very few particles (few hydrogen particles)
spread out very far
Work on Atmosphere graph activity
THE CARBON CYCLE
CHAPTER 2.5
A Little Background Info …
Carbon is an element. Basis of living things.
Organic Substances:
• Always contain atoms of carbon and hydrogen
and often contain oxygen and nitrogen atoms.
• EXAMPLES:
– Proteins, sugars, and fats
Inorganic Substances:
• Matter that doesn’t contain a combination of
carbon and hydrogen atoms
• EXAMPLES:
– Carbon Dioxide (CO2), water (H2O), and ammonia (NH3)
CYCLING OF ORGANIC MATTER
• The materials used in building the
bodies of living organisms are
limited to the atoms and molecules
that make up the planet.
• To maintain life, every carbon atom
is recycled time and time again into
new life forms.
The Cycle of Matter
Fox
CO2 + Energy
Rabbit
Plant
Leaves
Feed Matter
Decomposition
Decomposers
or Organic
Matter
Plant Roots
Inorganic
Materials
Inorganic
Molecules
Bacteria
• Organic Carbon is stored in:
– Living things
• Inorganic Carbon is stored in
THREE places:
– The atmosphere
– The ocean
– The earth’s crust
These storage places are called carbon
sinks.
• Carbon is removed from the
atmosphere by plants when they
photosynthesize to make sugar.
Photosynthesis
Reactants
Products
• 6CO2 + 6H2O + light C6H12O6 +6O2
Carbon Dioxide + water + light
Sugar ( Glucose) + oxygen
• Carbon is returned to the
atmosphere by plants and by
animals when they respire or
exhale.
Respiration
Reactants
Products
C6H12O6 + O2
CO2 + H2O
Sugar + oxygen
carbon dioxide + water
• Photosynthesis and cellular
respiration are complementary
processes.
• The carbon that they use is
repeatedly cycled, thus the name
CARBON CYCLE.
Atmosphere
• Most of the carbon that forms
living organisms is released to the
atmosphere or to water, as carbon
dioxide from dead, decaying
organisms.
Earth’s crust
• If decomposition doesn’t happen,
matter may be converted into rock
or fossil fuels such as coal,
petroleum and natural gas.
• This carbon is not released until
the combustion process takes place
through burning the fossil fuels.
The Ocean
• Carbon is found in sea shells and
bones. When these fall to the
bottom of the oceans and get
covered with sediment, they
decompose over millions of years to
form oil (one of the fossil fuels).
•
Shells and Bones
(Millions of tonnes of
soil)
Sink to the bottom of the ocean
Covered by sediment (Millions of years)
Form oil (example: Offshore drilling NFLD)
Reservoirs for Organic Carbon
• Organic carbon is also held in
reservoirs – the bodies of living
things.
• All living things die and
decomposition eventually returns
the carbon to the cycle in inorganic
form.
One Important Exception
• Bogs – store huge quantities of carbon in
organic form
• Bogs have very little oxygen, therefore
decomposition is very slow
• Carbon atoms may remain locked away in
dead plant matter (peat) for many years
in a bog.
• When plants decompose in a bog, they
form peat that can get trapped under
sediments over millions of years and
form coal (another form of fossil fuel)
PLANTS
Die in a bog and form Peat
Millions of years and tonnes of
pressure form coal
HOMEWORK
• QUESTIONS:
• Page 65
• #1,2,4,5,6a,7ad