Nitrogen Cycle Web

Nitrogen Cycle Web

1. Importance of Nitrogen

   • In plants Nitrogen is important for growth
   • For animals, it is essential for muscle functions and other functions of life
   • Important components of DNA + Protein
     • Essential for life processes in a cell

2. Human activities that effect the nitrogen cycle

   • Doubled the amount of available nitrogen in the biosphere in the past 50 years
     • has doubled from fossil fuel combustion in power plants aand processes such as sewage treatment.
     • Nitrogen is also released during the burning of fossil fuels in cars, trucks, and other forms of transportation
     • Some species like the algae thrive with the increased nitrogen level
       • This is good for the algae, but at the same time is killing off other marine life by taking away sunlight i oxygen

3. Cycles

   • Nitrification
     • Ammoniun (NH4+) is converted into nitrate (NO3-)
     • Takes place in 2 stages
       • 1. Nitrifying bacteria covert the ammonium into nitrate
       • 2. A different species of nitrifying bacteria convert nitrate to nitrite
     • This happens because not all plants live in association with nitrogen fixing bacteria, and have to obtain it another way
   • Denitrification
     • in terrestrial and aquatic ecosystems involves 'denitricating bacteria'
       • Denitrifying bacteria converts nitrate (NO3-) back into nitrogen gas
         • Nitrogen gas Gas (N2) isn't particularly useful
     • Nitrogen is returned to the atmosphere
   • Nitrogen Fixation
     • Nitrogen gas (N2) is converted to compounds containing nitrate (NO3-) and ammonium (NH4+) by nitrogen fixing bacteria
       • These compounds are usable by plants
     • Occurs in 3 ways: The atmosphere, in soil, and in water bodies
   • Uptake
     • When herbivores and omnivores eat plants, nitrogen from the plants go into the tissues with proteins
     • Uptake of nitrates is not only important for plants but organisms too

4. Sources

   • Other major stores include: Oceans, organic matter in soil.
   • Atmosphere
     • Stored as N2
   • in terrestrial ecosystems, living organisms, lakes and marshes also store nitrogen