Nitrogen Cycle

Lynae Dillehay

Mrs. Boresen

Expostiory Writing 6

Nitrogen Cycle

2/2/09


Nitrogen Cycle

The nitrogen cycle is also a very gaseous cycle. And just as the carbon cycle there are many attributes to it as well. A few of them are; atmospheric nitrogen gas, fixation of nitrogen gas, nitrogen gas becomes nitrates, and the denitrification of the nitrate to nitrous oxide. These are the attributes.

The atmospheric nitrogen gas is clearly unavailable to plants. This is so because it is atmospheric so it deals with the atmosphere not the plant life. The plants then depend on various types of bacteria to take up nitrogen gas and make it available to them. This is the nitrogen gases function.

Then the nitrogen gas becomes fixed. This means that nitrogen fixation occurs when the nitrogen gas is reduced and nitrogen is added to organic compounds. The atmospheric nitrogen is converted to ammonium by some cyanobacteria in the aquatic ecosystems and by nitrogen-fixing bacteria in the nodules on roots of legume plants in terrestrial ecosystems. The plants take up both NH4 and nitrate from the soil which is then enzymatically reduced to NH4 then used to produce amino acids and nucleic acids.

Another attribute is that the nitrogen gas becomes nitrates. This is the nitrification of the production of nitrates. The nitrogen gas is converted to nitrate by the cosmic radiation, meteor trails, and lighting in atmosphere. Some others are human manufacture of nitrates for use of fertilizers. In the soil the bacteria convert ammonium to nitrate in a two-step process. The first step is the nitrite-producing bacteria convert ammonia to nitrate. Then the nitrate-producing bacteria convert nitrite to nitrate. These two bacteria’s are called nitrifying bacteria. All of these factors do not depend on nitrogen gas.

Then there is the denitrification of the nitrates. This is the conversion of nitrate to nitrous oxide and nitrogen gas back to the atmosphere. To accomplish this task you denitrify the bacteria in both the aquatic and terrestrial ecosystems. Almost, notice the almost, counterbalances nitrogen fixation occurs.

So a brief description of an example is that of a, lets say rabbit. The rabbit starts the little flow chart. Then the rabbit decomposes setting off a gas to the decomposing bacteria to the ammonia. Then the ammonia travels to the nitrifying bacteria in the soil which then travels to the nitrate. This goes to the plants, which also travels from the exhaust of a tractor. This all winds in a little chart which repeats it’s self for forever.

As you can see the nitrogen cycle plays a big role in our survival as well. Every little thing has its own purpose in the cycle, doing it’s own role in survival. Although the nitrogen cycle does not bring on global warming…if it were terminated it would kill us all.