The document summarizes the nitrogen cycle. It describes the key steps: 1) Nitrogen fixation converts nitrogen gas to ammonia through diazotroph bacteria. 2) Nitrification converts ammonia to nitrites and nitrates through nitrifying bacteria. 3) Plants and animals assimilate nitrates and ammonia for growth. 4) Decomposition returns nitrogen to the soil as ammonium through ammonification. 5) Denitrification releases nitrogen back to the atmosphere through soil bacteria. Human activities like deforestation and fertilizer use can disturb nitrogen cycles and negatively impact the environment through acid rain, global warming, and pollution.

1. Presented By-
Pankaj chelak
M.Sc. 1st semester
S.O.S. in Environmental Science
Pt. Ravishankar Shukla University Raipur (C.G.)
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2. Table of Contents
Introduction
03
01 02
04
05
Nitrogen
Impact of Covid-19
Environmental Impact of
Nitrogen Cycles
2
Effect of Human Activities

3. Introduction
01o The nitrogen cycle refers to the movement
of nitrogen within and between the
atmosphere, biosphere, hydrosphere and
atmosphere.
o The nitrogen cycle matters because nitrogen
is an essential nutrient for sustaining life on
Earth.
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4. 02
o Present in some biomolecules like
nucleic acid .
o Present in atmosphere as N2
approximately 78%.
o Present in the ocean and fresh
water as NH3, NH4
+
, NO3
-
o Nitrogen is also present in soil as
NH3, NH4
+
, NO3
-
• used as a fertilizer
• Food Preservation
• melting point (−209.86 °C)
• Boiling point (−195.795 °C)
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5. o A very small amount of
nitrogen is fixed via
lightning interacting
with the air.
N2 NH3 or NH4
+
1. Nitrogen Fixation
Steps of Nitrogen Cycle
o Conversion of nitrogen (N2)
into ammonia (NH3) by
Diazotrophs like Rhizobium
(Beans and peas)
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6. Nitrifying bacteria add oxygen
to nitrogen in two steps:
STEP1:
Bacteria take in NH3 or NH4
+ & make
NO2
-Nitrite
Step2:
Bacteria take in NO2
- and make NO3
-
Nitrate
By – Nitrobactor like Nitrosomonas
2. Nitrification
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7. 3. Assimilation
Assimilation is the process by
which plants and animals uses
the NO3
- and ammonia formed
through nitrogen fixation and
nitrification.
Plants take up these forms
of nitrogen through their roots,
and incorporate them into plant
proteins and nucleic acids
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8. 4. Ammonification
When a plant or animal dies or an
animal expels waste, Bacteria or
fungi (decomposers) convert the
organic Nitrogen within the
remains back into ammonium
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9. 5.Denitrification
• Nitrogen is released back to the
atmosphere by bacteria get
their energy by breaking down
nitrate and nitrite into nitrogen
gas
• Soil organisms that live without
air in a wet soil and get their
oxygen
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10. 10

11. Marine Nitrogen cycle
N2 from the atmosphere.
Nitrogen cannot be utilized by
phytoplankton as N2 so it must
undergo nitrogen fixation which
is performed by cyanobacteria
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12. Effect of Human Activities
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03
• Deforestation
• Uses of fertilizer
• Industrial activities

13. Environmental Impact of
Nitrogen Cycles
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Plants need nitrogen to synthesize
chlorophyll and so the nitrogen cycle is
absolutely essential for them
As plants use nitrogen for their
biochemical processes, animals obtain
the nitrogen and nitrogen compounds
from plants. Nitrogen is needed as is an
integral part of the cell composition. It is
due to the nitrogen cycle that animals
are also able to utilize the nitrogen
present in the air.
Disturbance in Nitrogen cycles always cause negative
impact in environment
Acid rain
Global Warming
Pollution

14. 17
Dwindling air pollution
The vegetation is
growing better
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05 Impact of Covid-19

15. References
● Respected Sagar Kumar Rajak Sir
● https://en.wikipedia.org/w/index.php?title=Spe
cial:Search&search=bio+geo+chemical+cycle
&fulltext=1&profile=default&ns0=1
● Slide Go & slide share
● https://www.sciencelearn.org.nz/
● https://ugc.berkeley.edu/background-
content/nitrogen/
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16. Thanks you
DO YOU HAVE ANY
QUESTIONS?
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