carbon ,nitrogen and oxygen cycle with steps,.biogeochemicalcycles ,gaseous cycle

1. ASSIGNMENT ON
BIOGEOCHEMICAL
CYCLE
GASEOUS CYCLE
Assignment on
BIOGEOCHEMICAL
CYCLE-GASEOUS
CYCLE
Submitted by,
Tessa
Raju

2. BIOGEOCHEMICAL CYCLE
#Cyclic back and forth regenerative
movement of chemical elements
between organisms and their physical
environment is known as
“Biogeochemical cycle” [Vernadsky
1934]
#The flow of chemical elements and
compounds between living organisms
and the physical environment.

3. TYPES OF BIOGEOCHEMICAL
CYCLE
1.GASEOUS CYCLE:The term gaseous
cycle refers to the transformation of
gases between various
biogeochemical reservoirs;
Hydrosphere, Atmosphere and
Biosphere
a)Nitrogen Cycle
b) Oxygen Cycle
c) Carbon cycle
d) Water cycle

4. 2.SEDIMENTARYCYCLE:
Include leaching of minerals and
salts from the earth's crust, which
settle as sediment or rock before the
cycle repeats.
a)PHOSPHURUS CYCLE
b)SULFUR CYCLE
c)IRON CYCLE
d)CALCIUM CYCLE

5. NITROGEN CYCLE
Atmosphere air , which contains
nearly 19% of nitrogen is the richest
primary reservoir of
Nitrogen.So,Nitrogen cycle is a
typical gaseous cycle.
Defnition: The cyclic back and forth
movement of Nitrogen between
atmosphere and living organisms is
the fundamental,pathway of nitrogen
cycle.

6. A) NITROGEN CYCLE
Steps of Nitrogen cycle:
i. Nitrogen fixation
ii. Nitrogen assimilation
iii. Ammonification
iv. Nitrification
v. Denitrification
vi. Sedimentation

7. i) NITROGEN FIXATION
Three types:
a) Industrial nitrogen fixation
b) Non Biological nitrogen
fixation
c) Biological fixation

8. a) Industrial Nitrogen fixation
• Haber - Bosch process.
•1914 in Germany by Fritz Haber and
Karl Bosch.
N2 +3H2 500˚C (Ni)200atm 2NH3
•At High temperature
•At high pressure
• Presence of industrial catalyst

9. PhysioChemical nitrogen fixation involves the photochemical and
electrochemical conversion of atmosphere nitrogen to soil NO3, NO2
and NH3
 It is by ionising phenomena such as cosmic radiations,meteors ,
thunderstorms, lightning , volcanic eruptions etc
 These provide high energy to breaking the triple bond of N2
 Also for combination of free nitrogen with the
Oxygen/ hydrogen of atmospheric H2O
 N +O=N20 , NO(nitrous and
nitric oxide)
 N+H =NH3
b) NON-BIOLOGICAL NITROGEN FIXATION

10. •Nitrous and nitric oxides hydrated with
atmospheric water vapour form nitrous and
nitric acids.
• Rain water brings these acids and NH3 to soil
surface.
•Acids reacts with metallic ions metallic
nitrates which enrich the soil along with NH3

11. c) Biological nitrogen fixation
•Mostly accomplished by some
microorganisms, called diazotrophs or
nitrogen fixers .
•They include bacteria, blue green algae,
fungi, lichens etc.
Soil nitrogen fixers:
1 Symbiotic nitrogen fixers
2 Non-symbiotic nitrogen fixers

12. Free living /Non-symbiotic N fixers :
1. Inhabit both terrestial and aquatic habitat.
2. Bacteria and BGA Eg: Nostoc
3. Bacteria are aerobic Eg: Azotobacter
4. Bacteria anerobic Eg: Clostridium
5. Photosynthetic Eg :Rhodospirillum
Symbiotic nitrogen fixers :
1. Live within other organism (host) provide them safe
shelter , organic carbon and biological requirements
2. In return, hosts receive usable nitrogen
3. BGA [eg: Anabaena], Lichens Eg: collema and some
bacteria.
4. • Bacteria Rhizobium and Brandy rhizobium found in
root nodules of leguminous plant.

13. azotobacter
Nosto
c
ROOTNODULES

14. Il Nitrate assimilation
Most of the soil N03ˉ would be absorbed
by plants.
NO3 first reduced to NH3 by plants
This NH₃ is utilized for the synthesis of
amino acids, protein pigments, nucleic
acids etc - This is known as nitrate
assimilation or nitrate respiration
 From plants, nitrogen passes to animals
and decomposers through food chain in
the form of amino acids

15. It is the process of releasing ammonia by
certain microorganisms utilizing organic
compounds derived from the dead organic
remains of plants and animals and excreta of
animals.
After death and decomposition proteins
hydrolyzed to amino acids.
By action of actinomycetes fungi and some
bacteria called decomposing/ammonifying
bacteria. This amino acids transformed to soil
NH3 –Ammonification/ Mineralization .
iii) Ammonification

16. iv) Bacterial Nitrification
The soil NH3, produced by
ammonification, is soon oxidized to
soil NO3 in two steps. This is called
nitrification.
it is affected by 2 sets of
chemotrophic bacteria,called.
Nitrifying bacteria .
NH3 nitrite bacteria NO2ˉ
NO2ˉ nitrate bacteria NO3ˉ
Nitrite bacteria-Eg:Nitromonas,Nitrococcus
Nitrate bacteria-Eg:Nitrobacter

17. V Denitrification
•Some amount of soil NO3 is utilized fo
oxidative reactions by some denitrifying
bacteria [Eg: Pseudomonas]
• In them occurs reversal of nitrogen fixation
converting NO3 to NO2.
•The N2 thus produced returns to atmosphere
to be cycled again.
• Denitrification which completes, nitrogen
cycle

18. vi Sedimentation
Sometimes, nitrates of are
locked up in the rocks while
they are washed down to
the sea or leached deeply
into the earth along with
percolating water. These
phenomena is called

22. The carbon cycle is a" perfect gaseous"
cycle. It is a perfect cycle because this
transfers and transformations of carbon
compounds quickly and replenishment of
carbon is fast as its removal so that no
appreciable amount is lost from
biosphere circulation.
It is the back forth movement of carbon
between atmosphere and organisms
At first carbon moves from atmospheric
reservoir to producers
Then producers toconsumers to
decomposers
Finally to atmosphere from 3 groups
CARBON CYCLE

23.  Removal of carbon from the atmosphere occurs
through Photosynthesis and chemosynthesis
 it returns to the atmosphere occurs through
respiration, decomposition, combustion,
weathering, and dissolution of carbonate rock,
volcanic action, etc.
 From plants, carbon enters the grazing and
browsing food chain and reaches decomposers
through successive levels of consumers
 After the death of animals and plants, some
amount of carbon undergoes deep sedimentation
and gets incorporated in sedimentary rocks
 Some amount of CO2is released into the
atmosphere through -biological processes such as