pp siklus nutrien 10

8/12/2019 PP Siklus Nutrien 10

1/30

BIOGEOCHEMICAL CYCLING


2/30

All organisms require the six elements :CHNOPS

Depending on whether the local environmentis aerobic or anaerobic, the exact chemicalform of any of these elements may changequickly and drastically.

Example: If a soil becomes water logged andanaerobic, sulfate may be converted intohydrogen sulfide and nitrate into nitrogen gas

or ammonia (via anaerobic respiration). Aswater recedes and the soil becomes aerobicagain, the remaining ammonia is oxidizedback to nitrate in stages.


3/30

All of this (and many other processes) occurlargely because of the activities of soilmicrobes. Without these microbes, life as weknow it would not occur, because necessaryelements would remain tied up in unusablechemical forms and gradually be removed by

sedimentation.

Cycling and transfer of nutrients among allliving organisms :

biological and chemical processes involved rocks/soil -- atmosphere -- water


4/30


5/30

OXYGEN CYCLE

Photosynthesis

Respiration


6/30

CARBON CYCLE


7/30

The Chemical Cycles of

The Carbon Cycle

Siklus C : alur C antara living organisms

and the non-living environment.

Siklus C terdapat di alam sebagai gas(CO2).Di atmospher bumi 0,04% CO2, pd living

organisme 18% C.


8/30

C masuk ke dunia biotik oleh peran dari

autotroph :

1.Photoautotroph (tanaman dan algae)

konversi CO2mjd bahan organik selama

fotosintesis.2. Chemoautotroph(bakteri dan archae)

oksidasi molekul dalam substrat.

C kembali ke atm dan air melalui :1. respirasi2. pembakaran3. penguraian (CO2atau CH4)

The major cycling of C :


9/30

CO2

Primary

producersConsumers

Organic comp.Via organismsWithin Food chain

respiration

Photosinthesis and

chemosynthesis

CH4

Respiration &

mineralization

aerobic

anaerobic

CO2

exchange

Primary

producersConsumers

Organic comp. acetatVia organisms

Within Food chain

Photosinthesys

Anaerob

respiration &

fermentation

Methane

oxidation


10/30


11/30


12/30


13/30

NITROGEN CYCLE


14/30

Animal eat plants

N2

OrganicN (plants,microrganisms)

Nitrogen

fixation

(symbiotic

nonsymbiotic

Organic animal

NH3

DecompositionAmmonification

(microrganisms)

Chemical fixation

(Harber-Bosch)

NO2 Nitrification(Nit rosomonas)

NO3-

Nitrification

(Nitrobacter)

Denitrification

(Bacteria)

SinarMatahari

Utilization

of nitrate


15/30

Key processes :

Nitrogen fixation: N2--> NH3

only carried out by certain bacterial genera: Rhizobium(rootnodule symbionts), Azotobacter(free-living soil bacteria),

others.

aerobic or anaerobic; ~ 60% on land; 40% in oceans

Nitrogen fixers :(i) Azotobacter spp.- soil bacteria; occur in oxic environments

(ii)Klebsiella spp.- soil bacteria, can live in the presence or

absence of oxygen

(iii) Cyanobacteria(e.g. Anabeana spp., Nostoc) - water

bacteria; occur in oxic environments

(iv) Rhizobium spp.- plant symbionts; responsible forsignificant fixation.


16/30

Nitrogenase Protection

How do organisms living in oxic environmentsprotect their nitrogenase from oxygen ?(i) Azotobacter mempunyai laju respirasi sgt

tinggi.

(ii) The facultative aerobe Klebsiella mengfiksasi Nhanya jk lingkungan bebas dari O2.

(iii) Filamentous cyanobacteria mempunyai sel

heterocysts yg dpt mengfiksasi N, difusi O2lwt sel

ini rendah.

(iv) Rhizobia mempunyai leghemoglobin


17/30

Decomposition / ammonification: organic N

--> NH4+

carried out by chemoorganotrophs, both

aerobes and anaerobes

some recycled into organic N in soil; some

into atmosphere excretion of extra nitrogen is often in some

compound containing -NH2groups, which

quickly form ammonia (NH3

) once they are

liberated into the environment.


18/30

Nitrification: NH4+--> nitrite, nitrate

mostly chemolithotrophs; some

chemoorganotrophs in acidic areas aerobic conditions; mostly well-drained

soils at neutral pH

nitrate leached from soil by rainfall; water

runoff from fertilized areas can become

rich in nitrites, dangerous for animal

health

inhibitors are sometimes added tofertilizers. E.g., nitrapyrin - inhibits NH3

-->

nitrite (1st step); decreases pollution of

waterways


19/30

Step of nitrification :

1. First Step: Ammonium Oxidation

by ammonia oxidizers (ammonia-oxidizing

bacteria) : Nitrosomonas, Nitrosospira,

Nitrosococcus, Nitrosolobus

Biochemical Oxidation :

NH4++ 1/2 O2-------> NH2OH + H

+

Enzyme: Ammonia Monooxygenase

NH2OH + O2---------> NO2- + HOH + H+

Overall Reaction:

NH2++ 1 1/2 O2----> NO2

-+ HOH + 2H+.


20/30

2. Second step: Nitrite OxidationMikroorganisme (nitrate-oxidizing

bacteria) : Nitrobacter

Biochemical Oxidation :

NO2-+ 1/2 O2-----> NO3

-.


21/30

Denitrification: nitrate--> N2or NH3

chemoorganotrophs (anaerobic respiration)

Reduksi (NO3-) menjadi nitrogen gas atau Norganik.

NO3- -----> NO2- -----> NO -----> N2O -----> N2gas

Major Denitrifiers:* Pseudomonas spp.

* Bacillus spp.

Assimilatory nitrate reduction: nitrate -->organic nitrogen many organisms can carry this out


22/30


23/30


24/30

aerobic

anaerobic

NH3

N2

CyanobacteriaRhizobium

Azotobacter

NO2-

NH2 Groups of

proteinNO3

-

assimilation

deamination

Nit rosomonasNitrification

Nitrobacter

assimilation

NO2- NH2 Groups of

protein

assimilation

deamination

NO3 &N2O

N2denitrification

Pseudomonas,

other facultatif

anaerobs

N Fixation

Clost r id ium

pasteur iumPhototrophic

bacteria


25/30

PHOSPHOROUS CYCLE

PO43-

mineralize

immobilize


26/30


27/30


28/30

H2S

Organic S

(Animal)

Organic S

(plants &

microrganisms)

SO42-

S0

H2S oxidation

(Photosynthetic &

non photosynthetic

sulfur bacteria)

H2S oxidation

(Photosynthetic &

non photosynthetic

sulfur bacteria)

Decomposition

(microorganisms

Animal eat

plants

Sinar

MatahariSulfat reduction bacteria

Sinar

Matahar

i


29/30

Some major steps in the sulfur cycle include:

Assimilative reductionof sulfate (SO4=) into -SH

groups in proteins. Release of -SHto form H2S during excretion,

decomposition, and desulfurylation.

Oxidation of H2Sby chemolithotrophsto form

sulfur (S0) and sulfate (SO4=)

Dissimilative reductionof sulfate (SO4=) by

anaerobic respiration of sulfate-reducing bacteria.

Anaerobic oxidationof H2

S and S by anoxygenicphototrophic bacteria(purple and green bacteria)


30/30

SULFUR CYCLE

Oxidized

spontan

eous

S0

Oxidized by sulfur

bacteria

pp siklus nutrien 10

Documents