for energy to drive cellular functions

N is an important constituent of aa, proteins and nucleic acids (RNA, DNA)

All amino acid nitrogen are excreted in the form of urea and NH4+

Dietary proteins are the primary source of the nitrogen that is metabolized by the body

N containing a.a are used for the synthesis of proteins and other N containing compounds, or they are oxidized as fuel for energy

clean up the environment

decomposition of plant & animal matter

maintaining productive and healthy ecosystems

When the chemical process is not completed, nitrous oxide (N2O) can be formed

occur during nitrification and denitrification

N2O is a potent greenhouse gas

ozone-depleting substance

N enrichment due to usage of fertilizers

excess N of plant can leach from soils into waterways

A process where waterways, lakes and shallow sea areas receive excess nutrients that stimulate excessive plant or algae growth (bloom). This excessive growth depletes the available oxygen in the water(dead zone) and causes other organisms to die off

N as an integral component of cells

aa, proteins, DNA

enriching soil with necessary nutrients

key role in plant growth

convert inert N2 gas into usable form for plants

to produce aa (contain N & H) to make the special proteins that the plant cells need to grow

for chlorophyll synthesis used to make food via photosynthesis

lacking N, they become yellowed, with stunted growth, and produce smaller fruits and flowers

industrial process that creates fertilizers

under high heat and pressure

converts N (gas) into ammonia & N rich fertilizers

N(gas) + H(gas) > NH3

lightning provides the energy needed for N2 to react with oxygen

converts atm N into nitrogen oxide & nitrogen dioxide

N (gas) > NO & NO2

enters soil with rainfall/ snow

bacterial species in soil/ attached to plant roots (symbiosis) converts atm N into ammonium ions

N(gas) > NH4+

e.g. cyanobacteria, Rhizobactor, Frankia

can be used by plants, e.g. legumes(root nodules)

converted or ‘fixed’ to a more usable form

N moves from the atmosphere into the soil

completes the cycle by converting nitrate back to gaseous nitrogen

NO3- > N2 (gas)

denitrifying bacteria use nitrate instead of oxygen when obtaining energy, releasing nitrogen gas to the atm

e.g. anammox or ammonia oxidizing bacteria

nitrifying bacteria in the soil convert ammonia into nitrites and then into nitrates

NH3 > NO2- > NO3-

taken up from the soils by plants and then used in the formation of plant and animal proteins

2 bacterial species involved: Nitrosomonas (ammonia to nitrite) and Nitrobacter (nitrite to nitrates)

decomposition of organic matter

dead plants & animals or animal waste

ammonifying bacteria converts organic N into inorganic components (ammonia or ammonium)

N2 > NH3 / NH4+