Altering the Balance

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Altering the Balance

• Our impact on the Nitrogen Cycle

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Ways that humans add nitrogen to the environment

• Adding fertilizers
• Planting more legumes
• Burning fossil fuels

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Effects on the Soil
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• With a surplus of nitrogen plant growth becomes
  limited due to the imbalance of other nutrients.
• Nitrogen Saturation occurs
• Tree roots get damaged
• Tree growth is stunted
• Needles on coniferous trees can turn yellow and
  fall off.
• Soil acidity increases

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Effects on the atmosphere

• Nitrogen containing gases spew from industrial
  smokestacks, power plants and vehicle exhaust.
• The gases form Nitric Acid when dissolved in the
  moist air, which is a part of ACID RAIN

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• Acid rain can make land and lake environments
  more acidic.
• Acid in lake environments has killed fish, birds,
  amphibians and other organisms.
• The acid rain is also corrosive to the waxy layer
  on leaves, and therefore has a damaging effect on
  broad leafed trees.

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Effects on Fresh-Water Ecosystems (Rivers and
Lakes)

• Excess nitrogen from fertilizers is washed into
  lakes and streams due to run-off from local
  fields.
• This excess nitrogen causes the plant life at the
  surface of the lakes to grow rapidly.
• Plants that live below the surface are then
  unable to perform photosynthesis because they
  have no access to light, so they begin to die
  (and they no longer provide oxygen).

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• As the plants die, the population of decomposers
  explodes, as they feed on the decaying plant
  matter.
• The increase in decomposers causes a further
  decline in oxygen (due to their increased
  cellular respiration).
• The altered conditions kill fish and other
  organisms that require oxygen to live.
• This process is known as EUTROPHICATION

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Effects on Marine Ecosystems (Oceans)

• Added nitrogen originally creates a population
  explosion of algae in the warm surface waters.
  This is called an ALGAL BLOOM.
• As the algae die, they sink down to cooler waters
  where they are broken down by bacteria.
• The area near the seafloor may eventually contain
  little or no oxygen (because the decomposers have
  used it up cellular respiration)

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• The lack of oxygen causes the death of many
  oxygen-requiring organisms.
• The reduction of life at the bottom of the ocean
  has a significant effect throughout the
  neighboring food chains.