1. Fundamentals of Microbial Ecology
Concept of Microbial Ecology
Development of Microbial Communities
Succession & Colonisation

2. Fundamentals of Microbial Ecology
Concept of Microbial Ecology
Development of Microbial Communities
Succession & Colonisation
Relationship between microorganisms & their environments
Microbial Ecology
Abiotic
Biotic

3. Common Terms in Microbial Ecology
Basic Unit of Ecology comprising of biotic & abiotic components
Common Terms in Microbial Ecology
Ecosystem
Community of living organisms dealing with populations of MO’s
Biotic element
Consisting of clones of one or several species
Population
Chemical & physical conditions for microbial life
Abiotic
Organisms occupying place – Sediment, humus rich soil, nasal cavity, Intestinal tract
Habitat

4. Common Terms in Microbial Ecology
Specialized species (Leaf miners)
Microhabitat
Live only in the upper Photosynthetic layer of the leaves.
Leaf contributes a microhabitat for leaf miners.
Common Terms in Microbial Ecology
Leaf miners

5. Common Terms in Microbial Ecology
Niche
생태적 지위 
In general terms - organism lives
Functional role
Survival
Reproduction
Common Terms in Microbial Ecology
No two population can occupy the same niche at the same time
Eg. Cellulolytic bacteria
Cellulose- 셀룰로오스
degrade cellulose anaerobically
Gain energy by fermentation 발효
Maintain themselves & flourish in the rumen

6. Classification of microorganisms in ecosystem Autochthonous Zymogenous
Allochthonous
Indigenous 토착
Present in given ecosystem
Presence more or less number based on nutrient supply
Numbers constant in ecosystem
Soil
Intestine

7. Classification of microorganisms in ecosystem Autochthonous Zymogenous
Allochthonous
Occasional increase
Increase based on specific nutrient supply
Found in ecosystem at very low number
Eg. Cellulolytic microbes
Cellulose- 셀룰로오스
High number when soil cellulose is high

8. Classification of microorganisms in ecosystem Autochthonous Zymogenous
Allochthonous
Strangers in ecosystem / not permanent residents
Eg. Soil spores of soil dwellers
Present in air for short time period for dispersal

9. Concept of Microbial Ecology: Energy Flow
Ecosystems are in a dynamic steady state 역학 확고한
Controlling the activity of individual
Primary producer (use light in photosynthesis to reduce CO2)
Maintaining equilibrium 평형
Energy
Chemosynthetic bacteria
Use chemicals instead of light

10. “Primary Productivity” Stored energy in primary producers
(Kcal/m2/day)
Stored energy in primary producers
In the form of C or OM
Radiant Energy Chemical Energy
Sun  Producers  Consumers  Decomposers
(Metabolism) (Metabolism) (Metabolism)
Heat Energy Heat Energy Heat Energy

11. Mechanical Energy - two forms
Kinetic or free energy
Potential energy
Moving Energy
Measured by the amount of work done in bringing the body to rest
Stored Energy
Useful after conversion into kinetic energy
Organisms potential energy is chemical energy of food

12. Energy transfer in different steps Interrelationship of food chain
Food oxidation
Release energy
Used to do work
Chemical Energy
Mechanical Energy
Transfer of energy stored in organic compounds from one organism to other
Food Chain
Energy transfer in different steps
Trophic level
Interrelationship of food chain
Food web
Grazing Food web
Herbivores
Carnivores
Omnivores
Detrivores
Detritus Food Web
Eat dead bodies or decaying materials

13. BGC cycle Bio-geochemical Cycle (BGC)
Movement of material by biochemical activities
Atmosphere (air)
Hydrosphere (water)
Lithosphere (soil)
C, H, O, N, P & S
BGC cycle
Physical (Precipitation, Fixation) & Chemical transformation (Biosynthesis, biodegradation) & Combination of both
Microbes vital role
Energy absorbed, converted, temporarily stored & Flow

14. Adhesion 부착 Attachment properties of Microbes
All nontoxic, animate & inanimate surfaces
Adhesion 부착
Solid surface
Air-water interface
Bubble surface

15. Consequence 결과적 of phenomenon 현상 of adhesion 부착
Organic & inorganic nutrients
Extracellular enzymes
Adsorbed surface of object
Absorbed microbial surface
Microbes attachment
Extracellular polymeric substance
Prevent form predators or from desiccation
Survival of viruses & bacteriophages
Longer in natural environment if they are absorbed than when they are free.

16. Two stage process of attachment
Adsorption 흡착
Adhesion 부착
Physical or chemical adsorption
Not controlled by the organism
To attracts similar species to forming a colony
Organisms secrete Protein or Glycoprotein 당 단백질glue 아교

17. Van der Waal’s attraction Electrostatic repulsion
Adsorption 흡착
Adsorption is governed by two kinds of forces
Van der Waal’s attraction
Electrostatic repulsion
Attraction & repulsions between atoms, molecules, & surfaces, as well as other intermolecular forces
Van der Waals forces

18. 1) First layer is firmly (Tightly 단단히) attached
Bacteria & fungi
Soil Clay
Negatively charged surfaces at neutral pH owing anionic groups (COO-) within their wall polymers
Also negative charge due to isomorphic (iso-equal, morphe-shape) replacement.
These negative charged surfaces attract ions of opposite charge in two layers
1) First layer is firmly (Tightly 단단히) attached
2) Second layer is diffuse layer attachment (100 nm distance from surface)
Distance reduced to 0.5 nm in concentrated solutions of polyvalent ions (Na+ is univalent and Ca2+, Al3+ is polyvalent)

20. Effect surface chemistry
Attachment – either “adsorbed” or “produced by microbes”
Surface coating of material
Effect surface chemistry
Surface Chemistry study of substances surfaces - adsorption, the formation of colloids 콜로이드, heterogeneous catalysis, corrosion 부식, dissolution, crystallization, etc.
At a given ionic strength
Repulsion between bacterium & surface
The attachment charge is “directly proportional to distance between them”

22. The balance between the van der Waal’s forces of attraction and the electro static repulsion determines 결정 whether the bacterium is attracted to the surface or repelled from it.

23. Development of Microbial Communities

24. Highest biological Unit What is Community?
Made up of Individuals & Populations
What is Microbial Community?
Study of community - Synecology
Study of individual & population - Autecology
Interacting between them at given location
Assemblage of microbial populations
Habitat

25. Heterogenicity of ecosystem is diversity
What is Diversity 종 다양성?
Heterogenicity of ecosystem is diversity
Various organisms occurring together
Important role in food web
Food energy move by multitude pathway if community is diverse
Loss of one species cause changes or collapse community
Increase of one species – rise of predator population

26. Dominant species take most of energy
What is Diversity 종 다양성?
Biological communities
Few species with many individuals
Many species with few individual
Dominant species take most of energy
Dominant species determine the less & abundant species
1 or more population attain high number - Diversity decrease

27. What Determines Diversity 종 다양성?
- Community has complex structure
More number of species
Require low energy
Maintain ecosystem structure
Stable diversity
Dominant by single species
Require more energy
To maintain stable condition

28. Diversity related to abundance of ecological niches.
Complex community offers a variety of ecological niches than simple community.
Diversity inversely related to isolation.
Example: Islands 섬 less diverse than ecologically similar continents 대륙 because difficult many species reaching islands.
Diversity inversely 반대로 related to stress & extreme environments

29. ‘Edge effect’ – Where two ecosystems overlap, the overlapping area supports species from both, plus another species that is only found in the overlapping area.
Diversity reduced when anyone species becomes dominant within a community
So it is able to remove a disproportionate share of available resources
Thus preventing the growth of many other species.

30. Species Diversity Indices (SDI)
Several mathematical methods describe the species richness are called Species Diversity Indices (SDI) which are used to describe the assemblage of species diversity within a community.
But SDI cannot be applied to the microbial community due to technical difficulties (quantitatively the data is insufficient).

31. Pre-emptive Colonisation
Succession & Colonization
Colonisation
Succession
Outcome of Succession
Trends in Succession
Types of Succession
Pre-emptive Colonisation
Autogenic succession
Substrate succession

32. Primary succession (first appearance of MO’s)
Microbial  growth & reproduction on a material, animal or person without damage
Colonisation
Primary succession (first appearance of MO’s)
Habitat not previously colonised (eg. Gastro-intestinal tract of new born)
Succession occurs in a habitat with a previous colonisation (volcanic eruption, barren land 황무지, etc.)
Secondary succession
First colonisers of a virgin environment
Pioneer organisms

33. Pre-emptive Colonisation
Pioneer 개척자 organisms alter the condition in the habitat
Populations better adapted to the newly colonised habitat
New Organisms
Replace the pioneers
Succession ends when a relatively stable community called a climax community is achieved.
Gradually secondary invaders are also replaced.

34. Develop the Environment
New Environment
Climax community
Pioneer organisms
Succession ends
Stable community
Pre-emptive
colonisation
Develop the Environment
Alter the condition
Altered habitat
Not allowed further succession
Gradually secondary invaders

35. Climax community
Difficult to apply the concept of climax community to microbial community
No further changes
Because disturbance affect successional processes
So not reaching full equilibrium

36. Communities of organisms not exist suddenly but develop gradually by series of stages until they reach maturity state.
Succession
Individual populations of a community occupy the niches in the ecosystem.
Later, some populations are replaced by other populations that are better adapted to fill the ecological niches.
Ecological niche
Then Later
Ecological niche
Ecological niche
replaced by other populations
Ecological niche
Individual populations
Community

37. Succession is replacement of one community by another as the condition within the habitat changes
How its replaced?
Changes by the organism (by reduction in nutrient & oxygen level or changes in the pH) or changes from outside
New Environment
Pioneer organisms
Develop the Environment

38. When it reach the Ecological stability of the community?
Interrelationship among populations in a community & adaptations within a population contribute to the ecological stability of the community.
When it reach the Ecological stability of the community?
New Environment
Pioneer organisms
Develop the Environment
If microbes not have stability
Community continues..
Some interrelationships loose associations where one microbial population can replace the other (rhizosphere)
Some interrelationships tight associations where one microbial population cannot replace another (symbiotic association of Rhizobium).

39. Each stage in a succession is called sere Seral take long-term
Outcome of Succession
Each stage in a succession is called sere
Seral take long-term
New Environment
Pioneer organisms
sere
Develop the Environment
sere
sere

40. Starting with algae or lichens
Eg. Bare rocks
Starting with algae or lichens
Converted to stable soils
At the start of the sere
There is stress in the environment (very low nutrient) and the species diversity is low.
Bare rocks

41. Number of species grow increases
Habitat is colonised
Number of species grow increases
Reach climax (final stage)
Dynamic equilibrium between organism and environment
Stable

43. Stable communities
Finally the balance between the species vary slight
The overall list of organisms remain stable.
Individuals species come & go
Thus stability is not related to diversity but it is imposed from outside
Example, communities in hot thermal springs have a low species diversity but are very stable because of the environment.

44. No organisms disappear
Favourable climate
Hot summer
No organisms disappear
Low species diversity, but stable
Succession occurs due to influence of physical & chemical changes from outside the community.
Community succession begins with colonisation or invasion침입 of a habitat by microbial population.

45. Types of Succession Autogenic succession Allogenic succession
Microorganisms modify the habitat
Permits a new population to develop
Facultative anaerobes:  grow with or without oxygen because they metabolise energy aerobically or anaerobically.
Example: Creation of anaerobic conditions by facultative anaerobes allows the growth of obligate anaerobes.
Obligate anaerobes:  poisoned by oxygen, so they grow low Oxygen

46. Types of Succession Autogenic succession Allogenic succession
Substrate succession
Habitat is altered by environmental factors
Eg. salt marsh 바닷물이 드나 드는 늪 (zone between land & open salt water)
Pioneer organisms dominated by salt-loving organisms (eg. Algae)
Grow & add organic nutrients to the marsh
Followed by nitrogen fixing algae
Then coastal marshes converted completely into terrestrial communities

47. Types of Succession Autogenic succession Allogenic succession
Substracte succession
Microbes involved in the development of structured soils (eg. bare rock surfaces)
Low soluble minerals, no organic matter & so high temperature & moisture on the rocks
Uninhabited or virgin environment
Only tolerant algae & cyanobacteria with mucilaginous walls (갑옷) or slime capsule grow
Pioneer organisms
Fix nitrogen
(eg. Porphyrosiphon notarisu, Gloeocapsa spp., Gloecocystis spp., Nostoc muscorum)

48. Organic matter accumulates from wind-blown dust & oxygen
Algae & lichens then fungi & bacteria & then protozoa
These processes build up of primitive thin soil which has more nutrients (organic).
Nutrients set back to zero (or) diversity of microbes & nutrients support growth of higher plants

49. Sere shortened if organic matter is added from outside
Types of Succession
Autogenic succession
Allogenic succession
Substracte succession
Sere shortened if organic matter is added from outside
Long-term sere (from primitive to mature soil)
Many short-term changes in the microbial populations
Which reflect the colonisation of newly arrived species of organic matter

51. High organic matter (OM) in soil (plant litter & animal bodies)
OM stimulate 자극하다 microbial spores [break the dormancy (sleeping or quiescent) of spores]
High organic matter (OM) in soil (plant litter & animal bodies)
Increase zymogenous population (Mucor, Rhizopus)
Mucor
High competitive saprophytic ability (live on dead or decomposing matter)
Among bacteria (Bacillus & Pseudomonas)
Population slowly changes to ascomycetes, actinomycetes & protozoans.
Consumed easily utilizable substrates
pH drops due to immobilisation of cations
Organisms degrade fungal hyphae. Fungus is part of initial invasion (attack) of substrate

52. Succession of Final stage
Invasion (attack) by autochthonous organisms especially those degrading lignin (supporting material for algae tissues or plants)
Succession of Final stage
Activity of microorganisms increases
During a substrate succession
High environmental diversity
Utilisable nutrients used up & reduced
Species diversity decreased