Presentation is loading. Please wait.

Presentation is loading. Please wait.

Fundamentals of Microbial Ecology

Similar presentations


Presentation on theme: "Fundamentals of Microbial Ecology"— Presentation transcript:

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)

19

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”

21

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

42

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

50

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


Download ppt "Fundamentals of Microbial Ecology"

Similar presentations


Ads by Google