By: Alexander Kalogerou Chiyeung Lau Miriam Khan Charles Song The Nitrogen Cycle By: Alexander Kalogerou Chiyeung Lau Miriam Khan Charles Song

What is the nitrogen cycle?

The nitrogen cycle The nitrogen cycle is The transformation of nitrogen from an atmospheric gas to organic compounds in the soil, then to compounds in plants and eventually the release of nitrogen gas back into the atmosphere. Nitrogen is the most abundant element in our planet’s atmosphere. Approximately 78% of the atmosphere is comprised of this important element.

How does it work?

Why is nitrogen so important? All life requires nitrogen and it’s many compounds (proteins, nucleic acids) Nitrogen is found in the air however, we cannot use that form. Plants must secure their nitrogen as nitrate ions, ammonia and urea, then animals get their nitrogen from eating plants.

Nitrogen fixation The nitrogen cycle has aspects of both the carbon cycle and the phosphorus cycle. Bacteria's convert the gas into the ammonium form in Nitrogen Fixation. The bacterium live on nodules on the roots of legumes.

Nitrates and nitrites The nitrates and nitrites are used by plants to make amino acids which are then used to make plant proteins.

Plant eaters Plants are consumed by other organisms which use the plant amino acids to make their own. Animals waste are in the ground and bacteria's decompose it.

Decomposers Decomposers convert the nitrogen found in other organisms into ammonia and return it to the soil. A few of these type of bacteria return nitrogen to the atmosphere by a process called denitrification, however this amount is small.

The enormous energy of lightning breaks nitrogen molecules and enables their atoms to combine with oxygen in the air forming nitrogen oxides. These dissolve in rain, forming nitrates, that are carried to the earth. Atmospheric nitrogen fixation probably contributes some 5– 8% of the total nitrogen fixed.

How does the Nitrogen Cycle affect humans?

How humans have changed the Nitrogen Cycle The human use of legumes, chemical fertilizers and pollution from cars and factories has doubled the annual transfer of nitrogen in to useable forms. Agricultural fertilization , biomass burning and cattle feedlots has increased the nitrogen in the atmosphere.

What did we change? Because of our actions, we have changed the amount of nitrogen that is stored in reservoir Our use of fertilizer causes nitrates to wash into streams and ponds.

What the nitrogen cycle provides All animals need nitrogen to create amino acids, protein and DNA. Not all nitrogen is usable in the atmosphere. They have to be broken by something like a lightning strike. They can also be retrieved from the soil be created from bacteria. Animals get the nitrogen they need by consuming plants or other animals that contain organic molecules composed partially of nitrogen.

How animals are affected The increased nitrate levels cause plants to grow faster until they use up their nitrate supply and die. Herbivores will increase as the plant supply increases. The herbivores are left without a food source when these plants die. This will cause a change in the food cycle which will make it unstable.

How humans are affected

As Plants die we lose potential drugs. Humans will lose certain foods We will also lose useable resources The air we breathe loses quality due to pollutants that include high levels of nitrates. Dead zones- areas which animals can not survive, appear more frequently.

In the end As the humans change the nitrogen cycle, the nitrogen cycle changes us. Our quality of life decreases, along with the quality of scenery around us.

sources http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NitrogenCycle.html http://www.physicalgeography.net/fundamentals/9s.html http://www.visionlearning.com/library/module_viewer.php?mid=98 Images.google