Download Nitrogen Fixation

Nitrogen Fixation
November 21, 2011
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Things to remember!!
- Nov. 29th Science Scrapbooks check #2
- Mini-presentations on Nov. 30th (Ben, Ryan, Zack B.)
Nov 7­9:24 AM
Nitrogen Cycle:
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• Nitrogen occurs in all living organisms as a fundamental element in
amino acids which build our DNA & RNA.
• Nitrogen is the 4th most abundant element and is also found in the
atmosphere as a gas.
• Nitrogen is taken from the atmosphere and converted into usable
nitrogen in the process called nitrogen fixation.
Jul 7­3:55 PM
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Nitrogen Fixation
November 21, 2011
Nitrogen Fixation:
nitrogen fixation = process where nitrogen is taken from the
atmosphere which is in basic form, and convert it into a nitrogen
compound such as ammonia, nitrate, and nitrogen dioxide
2 Ways Nitrogen can be "fixed":
1. Lightening (5%)
2. Bacteria (95%)
Jul 7­6:04 PM
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Nitrogen Fixation by Lightning:
Sky
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Nitrogen Fixation
November 21, 2011
dead and fecal matter
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Nitrogen Fixation by Bacteria:
Outdoor scene
Human Impacts:
• Nitrogen overloads in ecosystems can be caused by:
à dumping of raw sewage
à burning of fossil fuels and wood
à overuse of fertilizers
• the bi-products of nitrogen overloads are nitrous
oxide, nitric oxide and ammonia all add to the green
house effect and global warming
Jul 7­6:20 PM
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Nitrogen Fixation
November 21, 2011
Classwork:
Worksheet:
"Nitrogen Cycle"
• Do not write on worksheet.
• Answer all questions on your own paper.
Jul 19­4:14 PM
Worksheet Answers:
1. How do animals obtain usable nitrogen? Why is it important?
Through the process of nitrogen fixation which can occur from
lightening or bacteria.
2. If nearly 79% of the atmosphere is made of nitrogen, how could
there be a shortage of nitrogen in soil?
The nitrogen in the atmosphere is not usable for plants as they can
only absorb nitrogen that is fixed with oxygen or hydrogen making it a
nitrate
3. Explain the two ways
nitrogen can be fixed.
Aug 27­7:33 PM
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Nitrogen Fixation
November 21, 2011
4. Explain why the tropical forest has a more lush plant life than the tundra in
regards to how fast things decompose.
The tropical forests are near the equator making them some of the warmest
places on earth. Because decomposition works the fastest in the heat as
materials can be broken down faster, and decomposers are able to work year
round (no freezing of ground) the rainforest‛s soil will be nitrogen rich all year
allowing the foliage to grow the most. The tundra is closer to the poles making
it much colder and also causing the ground to freeze part of the year which
does not allow for fast decomposition and only allows it to happen for parts of
the yearmaking the foliage much less lush.
5. Why have the following human impacts increased nitrogen in ecosystems.
a) manure
Manure is decomposing animal fecal matter, and left over food which both hold
nitrogen. By using manure in agriculture the amount of nitrogen will be
increased as bacteria will be able to break down the nitrogen into nitrates for
plants to gain from the soil.
b) continual harvesting of soy beans (nodule containing plants)
By continually harvesting soy bean plants you are continually putting plants that
have nodules on their roots which produce nitrates and in turn put any excess
nitrogen the plant odes not need into the soil. To prevent too much nitrogen
ending up in the soil nodule crops are rotated with crops that do not have
nodules.
c) burning forests
By burning forests we are releasing the nitrogen found in the trees and
releasing it into the air. This has been found to increase the amount of nitrogen
found in the air to a point that it is not being processed as fast as it is being
produced causing pollution such as acid rain, etc..
Aug 29­10:59 AM
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