Transcript Carbon Cycle

Carbon & Nitrogen Cycles
SE: 12E
Describe the flow of matter through the
carbon and nitrogen cycles and explain the
consequences of disrupting these cycles.
Carbon Cycle
• Carbon makes up less than 1% of
the Earth’s crust and atmosphere.
• All living things depend on carbon
compounds.
How does matter flow through
the Carbon Cycle?
1. Carbon mainly found in atmosphere as
CO2. CO2 leaves the atmosphere when
its dissolved in water or taken up by
plants for photosynthesis.
2. Carbon is released into the atmosphere
during cellular respiration, geologic
processes such as volcanic eruptions, &
when fossil fuels or forests are burned.
What happens when the carbon
cycle is disrupted?
• Human activity such as burning
fossil fuels and forests release CO2
into the atmosphere faster than it
can be removed by natural
processes.
3. CO2 is a greenhouse gas that
helps keep heat from leaving
atmosphere. The increased levels
of CO2 contributes to rising
temperatures and the global
climate change.
4. When CO2 dissolves in water,
carbonic acid forms. As more acid
forms, oceans are becoming more
acidic.
5. Certain organisms have a low
tolerance for changing pH levels in
the ocean. This can lead to loss of
biodiversity.
6. What happens if there is too
much CO2 in the atmosphere?
• Global warming
7. What would cause too much CO2
in the atmosphere?
• rainforest deforestation
• grassland conversion
• too much pollution – from cars,
factories
What are the causes of the
disruption to carbon cycle?
Deforestation - removal of a forest
or stand of trees where the land is
thereafter converted to a
nonforest use
Grassland Conversion – altering
grasslands to farmland
Why does
deforestation/grassland
conversion occur?
• People need land to grow
crops or raise animals
• People need land to live –
development of houses,
cities, shopping malls, etc…
Nitrogen Cycle
• Nitrogen gas makes up 78% of
the Earth’s atmosphere.
8. Nitrogen is removed from the
atmosphere by a process called
nitrogen fixation. The nitrogen is
“fixed” or changed into a form that
living things can use.
Nitrogen Fixation
• Certain bacteria in the soil and water
are able to fix nitrogen. Some of
these bacteria live inside the roots of
certain plants. The plants are then
able to use the nitrogen.
9. Lightning can also fix nitrogen.
10. On the other hand, Denitrifying
bacteria return nitrogen to the
atmosphere thus removing nitrogen
from soil.
What happens when the
Nitrogen Cycle is disrupted?
9. Farmers often add fertilizer to the soil
to increase plant growth. Fertilizer runoff
can affect the balance of nitrogen in water
(rivers, lakes, streams).
10. Eutrophication is the process in
which nitrogen dissolves in a body of
water and stimulates growth of plants and
algae.
• When plants and algae die,
bacterial populations that feed on
dead matter rise.
• These bacteria consume so much
oxygen from the water that fish
and other aquatic animals cannot
survive.
11. Acid precipitation aka acid rain is
another consequence of disrupting the
nitrogen cycle.
• The pH levels of soil and water are
altered and leads to death of plants
and animals.
• Acid rain can also cause harmful
metals to leach from pipes and enter
drinking water.
Plants need Nitrogen, what
would happen if there wasn’t
enough nitrogen for plants?
Plants wouldn’t have nutrients to
grow & would be very small