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Ch10 MIcrobial ecology

FUNDAMENTAL MICROBIOLOGY

Chapter 10
INTRODUCTION TO MICROBIAL
ECOLOGY


What is Microbial Ecology?
What is “Microbial”?
– of or referring to a minute life form; a
microorganism, especially a bacterium that causes
disease. Not in technical use.

What is “Ecology”?
– the study of the interactions between organisms
and their environment
Microbial ecology = The study of interactions between
microorganisms and their environment (chemical, physical,
and biological environment!)
Applied microbiology – study of practical uses of
microbes in food processing, industrial production, and

biotechnology



Organization of Ecosystems
Biosphere
 –
 thick
 envelope
 of
 life
 that
 
surrounds
 the
 earth’s
 surface
 
•  Made
 up
 of:
 
–  hydrosphere
 (water)
 
–  lithosphere
 (soil)
 
–  atmosphere
 (air)
 

•  Maintains
 and
 creates
 the
 condi  of
 
temperature,
 light,
 gases,
 moisture,
 and
 
minerals
 required
 for
 life
 processes
 
•  Biomes-­‐
 par  clima  regions
 


Organization of Ecosystems
•  Communi-es
 –
 the
 associa  of
 organisms
 that
 
live
  together
  and
  that
  exhibit
  well-­‐defined
 
nutri  or
 behavioral
 interrela  
•  Popula-on
  –
  organisms
  of
  the
  same
  species
 
within
 a
 community
 
•  Habitat
 –
 the
 physical
 loca  in
 the
 
environment
 to
 which
 an
 organism
 has
 adapted
 
•  Niche
  –
  overall
  role
  that
  a
  species,
  or
  popula  
serves
  in
  a
  community;
  nutri   intake,
 
posi   in
  the
  community,
  and
  rate
  of
 
popula  growth
 


In microbial ecology the main concepts

population - an elementary evolutional
unit (structure) of a definite species;
biotope - site, habitation of a population,
for parasites - place of their localization
in an organism;


In microbial ecology the main concepts
microbiocenosis - microbial association, that is
collection of populations of different species of
microorganisms, which live in the defined biotope (for
example, in an oral cavity, skin);
ecosystem - system, in which enters a biotope and
microbiocenosis.


Energy
 and
 Nutritional
 Flow
 in
 Ecosystems
 
-­‐
  O r g a n i s m s
 
derive
  nutrients
 
and
 energy
 from
 
their
 habitat.
 
-­‐
  Energy
  does
 
not
 cycle.
 
-­‐
  As
  energy
  is
 
transferred
  to
 
the
 next
 level
 

Energy
 pyramid
 


Feeding relationships
are represented by a
food web which
represents the actual
nutritional structure
of a community.



producers

consumers

The role of microorganisms?
Help in

decomposers

Ø  the decomposition of pollutants and toxic wastes
Ø  the efficient utilization of limited natural resources
Ø  transformations of chemical substances that can be
used by other organisms


what are the important effects of microbial groups in nature
Ecological roles of several microbial groups

Ecological role

Primary producers

Secondary producers, assimilating
dissolved organic matter

Principal Microbial groups involved

photoautotrophs ( microalagae&photosynthetic bacteria)
Chemoautotrophs( bacteria& archaea)

!

Bacteria, archaea,fungi,protozoa

a food source for consumers

Microalgae, cyanobacteria, bacteria,archaea, protozoa

important links between producers
and top consumers

protozoa

Decomposing organic matter

Bacteria, archaea, fungi

biogeochemical cycling

All

structuring communities

Viruses, Bacteria

Soil formation

Fungi, bacteria


Where do microorganisms occur?
•  Soil
 borne
 
•  Water
 borne
 
•  Air
 borne
 


Microflora of soil
Topsoil

Subsoil

Bedrock

Organics,
nutrients

Numbers of
microorganisms

Decrease
with depth

Decrease
with depth
but still
present in
bedrock


Microflora of soil
•  The soil is the major environment
for a habitation of microorganisms.
•  The amount of bacteria in one gram
of soil can be very great - from 200
millions up to 10 billions
•  The ground mass of bacteria is on
depth 10-20 cm.
•  >11,000 species of bacteria,

Fungi, protozoa, viruses


Soil is alive…
Various species of putrefactiving,
ammonifying, nitrifying, denitrifying,
nitrogen-fixing bacteria, iron bacteria
and sulphur-bacteria.
The most often inhabitants of soil are
genus Azotobacter, Nocardia and
Clostridium.





Microflora in water



Microflora of air
•  Atmosphere
 (The
 layer
 nearest
 to
 the
 earth)
 contains
 all
 
major
  groups
  of
  microbes
  ranging
  from
  algae
  to
  the
 
viruses.
 
 
•  There
 are
 vegeta-ve
 cells
 and
 spores
 of
 bacteria,
 fungi
 
and
 algae,
 viruses
 and
 protozoan
 cysts.
 
•  Exposed
  to
  sunlight,
  air
  has
  a
  higher
  temperature
  and
 
less
 moisture.
 
•  The
  main
  sources
  of
  airborne
  microorganism
  is
  human
 
beings
  by
  ac   like
  coughing,
  sneezing,
  talking
  and
 
laughing
 
à
 most
 of
 these
 microbial
 forms
 will
 die
 


Algal spores

MICROBES
in the AIR
Common bacteria
E.coli
Seretia marcesens
Staphylococcus aureus

Fungal spores
Dust particles
Water vapour
Gases

(Microbiologyprocedure, 2008)‫‏‬


Aerosols
machine fans
air conditioners
vents

Man's Actions
ploughing
digging
excavation
construction
irrigation
fertilizers

Wind blown
long suspension time

The SOURCES
of Microbes in Air
Water droplets
fountains
streams
ponds
rivers

Human/Animal
breath
cough
sneeze
talk
laugh


Droplets

mucous
saliva
talking
coughing
sneezing

Infectious dust

dried secretions
culturing microbes
handkerchief
3 Forms of
bed making
Discharge
clothes
grouped via size and
sweeping
moisture content

Droplet Nuclei

1-4 µm dry solid of a droplet
ability to travel distances

survival limited by:
l  humidity
l  sunlight
l  susceptibility


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