The Nitrogen Cycle and Importance of Oxygen
is a vital element of protein and is absorbed by green plants in the form of
with ammonia, ammonium and nitrite, it is found naturally in rivers, lakes
and streams in very small quantities
a pond environment, nitrogen compounds (nutrients) can be created quickly by
faeces, urine and other excreta, plant remains and decaying food.
concentrated these nutrients can have a harmful effect on a ponds
nitrogenous substances decay in stages in the presence of oxygen, a process
called ‘oxidative breakdown’. It produces various nitrogen compounds
(nutrients) as follows…
ammonia and non-toxic ammonium are produced in the first stage of the
The pH value
determines which of the two will predominate. Ammonia occurs at a pH of 7.0
stage of the nitrogen cycle is nitrite which is the result of the bacterial
or combustion, of ammonia/ammonium.
also toxic to aquatic life, but not as toxic as ammonia.
the third and final stage nitrite is converted to nitrate. Nitrate is
harmful only in very high concentrations.
element and most important factor to get all of the above to work is the
availability of free oxygen.
Back to Main index