Nitrogen Cycle by Wenying

Nitrogen Cycle:

*Processes
*Cycle as a whole

Nitrogen Gas molecules are released into the atmosphere through Fossil Fuel Emissions. It is dissolved in clouds or water vapour which falls back to Earth as Precipitation. From The Gaseous Atmospheric Nitrogen Store, Nitrogen undergoes 2 processes: 1) Lightning Fixation, 2) Bacteria Fixation. Nitrogen is then ‘absorbed’ into 1) Organic Matter and 2) Fertilizers.

1) Organic Matter: First Nitrogen undergoes Mineralization and bonds with Hydrogen Atoms, to form Ammonium (NH4). Through a process called Nitrification, Ammonium molecules are broken apart to combine with oxygen atoms in the air, forming Nitrites (NO2) then Nitrates (NO3), which dissolves in rain and falls back to Earth.

2) Fertilizers: Nitrogen absorbed in the soil in plants will undergo Leaching, where the nitrogen compounds are moved from one place to another without a change in its compound structure. Eutrophication is where Nitrogen will end up as nutrients in water bodies (eg. Amazon river), which gets accumulated over time. It can cause the marine organisms to be unable to receive sunlight this is especially crucial for plants because photosynthesis would be less productive.

Nitrates that have fall back onto Earth would either 1) be consumed by plants or 2) Through Denitrification, be returned to the atmosphere as Gaseous Losses (N2 & N2O)

& the cycle would repeat itself again.

30 January 2010.