Biogeochemical Cycles

1
(No Transcript)
2

• Biochemists are scientists who study the type of
  chemical compounds that are found in living
  things.
• The work of biochemists has led to the
  realization that living organisms are composed of
  some of the same elements that are found in the
  air, water and soil. There are 92 elements know
  to occur naturally on Earth, however fewer than
  20 elements occur in the tissues of living
  things.
• Only 6 elements make up 99.2 of human or pumpkin
  tissues.

3

• oxygen, carbon, hydrogen and nitrogen make up the
  vast majority of living tissue.
• These four elements are recycled between living
  organisms and the soil, water and atmosphere of
  the Earth. These elements are first taken up by
  plants
• some oxygen is released to the atmosphere as a
  product of photosynthesis, but the rest is
  converted into food, and passed through the food
  web.
• as they pass through plants, consumers, and
  finally decomposers, and then returned to the
  environment in a continuous recycling of
  materials.
• If recycling of these materials did not occur,
  life could not exist.

4

• Some of these elements (carbon, oxygen, sulfur,
  nitrogen) are found in gaseous forms and their
  cycles involve the atmosphere. As a result they
  have a global nature.
• elements may have a short term cycle such as
  when carbon is transferred from animals to
  plants in the form of carbon dioxide
• and a long term cycle such as the transfer of
  carbon from a fossil fuel to a plant following
  combustion.

5

• The elements are cycled between the living
  organisms and the environment in a combination of
  biological and geological processes that drives
  chemical recycling.
• Biological processes include
•          respiration,
•          decomposition,
•          excretion,
•          photosynthesis,
•          and assimilation.
• Geological processes involve
• fossilization
• Erosion
• combustion of fossil fuels (peat, oil, coal),
• weathering
• formation of sedimentary rock.

6
Carbon Cycle
7

• Plants take carbon dioxide and water from their
  environment.
• They use the energy they capture from the sun to
  carry on a process known as photosynthesis which
  converts the atoms in the carbon dioxide and
  water into sugar (glucose) and oxygen.
• 6CO2 6H2O energy ? C6H12O6 6O2 

8
(No Transcript)
9

• The oxygen, released as a byproduct of
  photosynthesis, generally passes into the
  atmosphere.
• The sugar (known as glucose) serves as food for
  all consumers in the ecosystem.
• The consumers carry on a metabolic process known
  as cellular respiration. where oxygen is taken in
  from the atmosphere and used to break down the
  sugar resulting in a release of energy and the
  molecular products, carbon dioxide and water.
• Respiration chemical equation
• C6H12O6 6O2 ? 6CO2 6H2O energy

10
Carbon is the centre to life..

• All living things contain carbon.
• Carbon is the link that allow plants to transform
  sunlight into chemical energy.
• The sugar (glucose) produced during
  photosynthesis forms the basic substance that is
  transferred along food chains.

11

• Carbon dioxide in the atmosphere is very small,
  0.03
• However, without the carbon cycle we would
  quickly run out of carbon dioxide, plants could
  not trap sunlight, and life on earth would cease.

12
Organic and Inorganic

• Organic substances always contain carbon and
  hydrogen, and often contain oxygen and nitrogen.
• Important chemicals that make up your body such
  as proteins, sugar and fats are considered
  organic.
• Inorganic matter doesnt contain a combination of
  carbon and hydrogen.
• For example carbon dioxide (CO2), water (H2O)
  and ammonia (NH3) are inorganic.

13
Inorganic carbon storage

• 1. Atmosphere a small amount in the carbon
  dioxide in the air we breathe and is available
  for photosynthesis.
• 2.Ocean a large amount is found in the oceans.
  This is available to algae and other water plants
  for phototypesets.
• 3. Earths crust the largest storage of inorganic
  carbon is in the sedimentary rocks, such as
  limestone, that have formed from the remains of
  living things.

14
Organic Carbon Storage

• In the bodies of living organisms.
• When living things die, their bodies decompose
  and the carbon is returned to the cycle in
  inorganic form.

15

• Because there is limited oxygen in bogs,
  decomposition takes thousands of years.
• Carbon may remain locked away for many year in
  organic form.
• Carbon locked away in dead plants is know as
  peat.
• When peat is covered in sediment for a long time
  it will become coal, a carbon containing fossile
  fuel.
• Other fossil flues such as
• oil and gas contain organic
• carbon that has been trapped
• in the earths crust for
• millions of years.

16

17
Human Activity

• People have discovered these fossil fuel deposits
  and have used them to supply our energy needs.
• Humans have also affected the carbon cycle by
  cutting down forests.  As a result of human
  activity, the amount of carbon dioxide is being
  produced at a faster rate than nature can recycle
  it.
• As a result of this imbalance, the amount of
  carbon dioxide in the atmosphere is increasing.
  As a result the earth is presently undergoing an
  enhanced greenhouse effect in which the
  atmosphere is gradually heating up.
• If the rise in temperature occurs too fast for
  organisms to adapt, widespread extinction of
  plants and animals may be the result.

18
(No Transcript)
19
What are the impacts of deforestation on the
carbon cycle

• Removing large amounts of trees will reduce the
  amount of carbon dioxide that is taken out of the
  atmosphere due to a decreases in photosynthesis.
• If threes are burned there will be an increase of
  carbon dioxide released into the atmosphere.
• The forest acts as a carbon sink retaining carbon
  for long periods of time.