Nitrogen Sulphur cycles

1. NITROGEN CYCLE
Presented By: Sumbul Faizee
Roll#529
MSc. Botany(evening)
Presented to : MA’M HINAASHRAF.

2. DEFINITION
• The cycling of Nitrogen in and our of environment is called NITROGEN
CYCLING.
• OR
The Process of Cycling of nitrogen molecule
• and its incorporation in environment is
• called NITROGEN CYCLE.

3. OVER VIEW
This Process consists of 5 main steps named as follows:
1-Nitrogen Fixation ( N2 to NH3)
2-Nitrification (NH3 to NO3‾)
3-Assimilation(NH3 to NO3)
4-Ammonification (organic componds to NH3)
5-Denitrification (NO3 to N2)

4. DISAMBIGUATION
Nitrogen fixation
Conversion of gaseous
Nitrogen i.e N2 to NH3 or
NH4 .This can be
1-Biological Fixation :By
nitrogen fixing bacteria in roots
of family Leguminosae.
2-Non Biological: By thunder
storming in air naturally during
rain fixes nitrogen.
Nitrification
Conversion of NH3/NH4 into
NO3‾.This is done by
1-Nitrosomonas and
Nitrococcus that convert NH3
to NO2 and
2-Nitrobacter that oxidizes
NO2‾ to NO3‾ .
Assimilation
Incorporation of Nitrogen into
biological components .
1-Plants : Get nitrogen from
their roots and incorporate it in
proteins and NA’s.
2-Animals: Get nitrogen from
plants and Utilize it.

5. Ammonification
Conversion of organic nitrogen
back into ammonia.
It is produced by animals in
large quantities and returned
back to environment in from of
Ammonia i.e NH3.
Denitrification
Reduction of NO3‾ to gaseous
N2 by anaerobic Bacteria.
This process occurs in a little or
no oxygen level.

7. PHOSPHORUS CYCLE
GROUP # 6

8. DEFINITION
• The movement of phosphorous in and out of environment is
Phosphorous cycle.
• OR
• The cycling of phosphorous in environment is called
PHOSPHROUS CYCLE.

9. EXPLANATION
• First Cycle
• Cycle starts out in the earth’s soil
• When plants grow they are consumed by herbivores and omnivores
• The animal wastes called debris or detritus is non living organic material retained by soil.
• The dead animals convert organic to inorganic phosphates.
• Second Cycle
• The phosphorus in soil moves on and transfers its phosphates to Rocla underwater.when
uplifting of rocks occur it takes the phosphate along with it.After that the weathering of
rocks occur and rocks began to break down into soil and the cycle starts again.

10. SULPHUR CYCLE
GROUP # 6

11. DEFINITION
•The Cycling of phosphate in and out of
environment is called cycling of SULPHUR.
•OR
•The Sulphur cycling in its combined and sole form
in environment id called Sulphur Cycle

12. DETAIL
• Mineralization of organic sulfur into inorganic forms, such
as hydrogen sulfide (H2S), elemental sulfur, as well as sulfide
minerals.
• Oxidation of hydrogen sulfide, sulfide, and elemental sulfur (S)
to sulfate (SO4
2−).
• Reduction of sulfate to sulfide.
• Incorporation of sulfide into organic compounds (including
metal-containing derivatives)