This document discusses microbial ecology and the diversity of microbes found in different environments. It describes how microbial ecology studies the relationships between microorganisms and their environments. It notes that less than 1% of microbial species have been identified. It discusses various microbial habitats including soil, water, other organisms, and extreme environments like those that are very hot, cold, acidic, or high pressure. It provides examples of oligotrophs, thermophiles, psychrophiles, and barophiles - microbes that thrive in nutrient-poor, hot, cold, and high pressure conditions, respectively.

1. Prepared by –
Dr Misbah Ajaz
Dept. Of Microbiology
BGSBU-Rajouri
Ecological Diversity Of
Microbes

2. Microbial Ecology
• It studies the diversity of microorganisms by
characterizing bacterial communities in different
environments and determining the factors that
drive diversity in these communities
or
• Also known as environmental microbiology is
the ecology of microorganisms: their relationship
with one another and with their environment.
• It concerns the three major domains of life—
Eukaryota, Archae ,Bacteria as well as Viruses
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

3. continue
• Most types of microbes remain unknown.
• It is estimated that we know fewer than 1% of
the microbial species on Earth.
• Microbes surround us everywhere -- air, water,
soil.
• An average gram of soil contains one billion
(1,000,000,000) microbes representing
probably several thousand species.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

4. Why is it important to study Microbial Ecology?
• Microorganisms are the backbone of
all Ecosystems,
• In zones where photosynthesis is unable to take
place because of the absence of
light, Chemosynthetic microbes provide energy
and carbon to the other organisms.
• These chemotropic organisms can also function
in environments lacking oxygen by using other
Electron acceptors for their respiration.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

5. Continued
• Other microbes are decomposers: ability to
recycle nutrients from other organisms' waste
products.
• Microbes play a vital role in biogeochemical
cycles:N cycle, P cycle, and C cycle all depend
on microorganisms in one way or another
• Due to the high level of horizontal gene
transfer among microbial
communities, microbial ecology is also of
importance to studies of evolution.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

6. Microbial habitats
• These are found in just about every kind of
habitat.
• Microbes are incredibly diverse thriving in
environments from the very cold to the
extremely hot.
• They are also tolerant of many other
conditions such as limited Water availability
high salt content and low oxygen levels.
• Not every microbe can survive in all habitats.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

7. 1. Terrestrial Microbial Habitats
• Only one percent of microbes that live in soil
have been identified.
• These organisms take part in the formation of soil
and are essential components of their
ecosystems.
• Bacteria and fungi that live in soil feed mostly on
organic matter such as other plants and animals.
• These microbes are very sensitive to their local
environment.
• Factors such as the levels of carbon dioxide and
oxygen, pH,moisture and temperature all affect
the growth of microbes in the soil.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

8. 2.Aquatic Microbial Habitat
• Microbes live in both fresh and salt water.
• These organisms include microscopic plants
and animals as well as bacteria fungi and
viruses.
• As with other microbes the ones that live in
water are adapted to the specific conditions of
their environment.
• Habitats range from ocean water with an
extremely high salt content to freshwater lakes
or rivers.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

9. 3. Microbial Habitats on Other
Organisms
• Microbes also live on other organisms.
• As with the ones found on people these microbes can be
harmful or beneficial to the host.
• Example: Bacteria grow in nodules on the roots of pea and
bean plants.
• These microbes convert nitrogen from the air into a form
that the plants can use.
• In many ways animals and plants have evolved as habitats
for the millions of microbes that call them home.
9Dr Misbah Ajaz,
Dept Of Microbiology,BGSBU-Rajouri

10. 4.Extreme Microbial Environments
• An extreme environment contains conditions that
are hard to survive for most known life forms.E.g,
1. Oligotrophs,
2. Thermophiles,
3. Psychrophiles,
4. Barophiles,
5. Organic solvent tolerant.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

11. Types of extreme environments
1. Alkaline: broadly conceived as natural habitats above
pH 9 whether persistently, or with regular frequency
or for protracted periods of time.
2. Acidic: broadly conceived as natural habitats below
pH 3 whether persistently, or with regular frequency
or for protracted periods of time.
3. Extremely cold: broadly conceived habitats
periodically or consistently below -17 °C either
persistently, or with regular frequency or for
protracted periods of time.
• Includes mountain sites, polar sites, and deep ocean
habitats.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

12. continued
4. Extremely hot: broadly conceived habitats
periodically or consistently in excess of 55 °C
either persistently, or with regular frequency or
for protracted periods of time.
• Includes sites with geological thermal influences
such as Yellowstone and comparable locations
worldwide or deep-sea vents.
5. Hypersaline: (high salt) environments with salt
concentrations greater than that of seawater,
that is, >3.5%.
• Includes salt lakes.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

13. continued
6. Under pressure: broadly conceived as habitats
under extreme hydrostatic pressure— i.e. aquatic
habitats deeper than 2000 meters and enclosed
habitats under pressure.
• Includes habitats in oceans and deep lakes.
7. Radiation: broadly conceived as habitats
exposed to abnormally high radiation or of
radiation outside the normal range of light.
• Includes habitats exposed to high UV and IR
radiation.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

14. continued
8. Without water: broadly conceived as habitats without free
water whether persistently, or with regular frequency or for
protracted periods of time.
• Includes hot and cold desert environments, and some
endolithic habitats.
9. Without oxygen: broadly conceived as habitats without
free oxygen – whether persistently, or with regular
frequency, or for protracted periods of time.
• Includes habitats in deeper sediments.
10. Altered by humans, i.e. anthropogenically impacted
habitats.
• Includes mine tailings,oil impacted habitats, and pollution
by heavy metals or organic compounds.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

15. OLIGOTROPHS
• Etymology:-the word "Oligotroph" Is a
combination of the greek
• An oligotroph is an organism that can live in an
environment that offers very low levels of
nutrients.
• Oligotrophs are characterized by slow growth,
low rates of metabolism, and generally low
population density.
• According to lab definition, oligotroph is an
organism
• that is capable of growth in a medium containing
0.2–16.8 mg dissolved organic carbon per liter.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

16. OCCURENECE
• Deep oceanic sediments,
• Caves,
• Glacial and polar ice,
• Deep subsurface soil,
• Aquifers,
• Ocean waters, and
• Leached soils.
• In natural ecosystems, oligotrophs and eutrophs
(copiotrophs) coexist, and their proportion is
dependent on the ability of an individual to dominate
in a particular environment.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

17. EXAMPLES
• Oligotrophic bacterium sphingomonas sp. :-isolated
from the resurrection bay, alaska retained its
ultramicrosize irrespective of the growth phase,
carbon source, or carbon concentration.
• Cycloclasticus oligotrophicus :-isolated from the
resurrection bay, shared properties similar to
sphingomonas (e.g. Single copy of the rRNA operon,
relatively small size and genome size).
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

18. THERMOPHILES
• A thermophile is an organism
that thrives at relatively high
temperatures. Or
• A thermophile is an organism
capable of living at
temperatures at or near the
maximum.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

19. OCCURRENCE
• Composts,
• Sun-heated soils,
• Terrestrial hot springs,
• Submarine hydrothermal vents and
• Geothermally heated oil reserves and oil wells.
• Various geothermally heated regions of the earth, such as
hot springs like those in yellowstone national park.
• The diversity of bacteria of a hot spring in bukreshwar
(west bengal, india) is also a home of thermophile.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

20. Examples
• Few thermophilic fungi belonging to
• Zygomycetes (Rhizomucor miehei, R. pusillus),
• Ascomycetes (Chaetomium thermophile, Thermoascus
aurantiacus, Dactylomyces thermophilus,
Melanocarpus albomyces, Talaromyces thermophilus,
T. emersonii, Thielavia terrestris),
• Basidiomycetes (Phanerochaete chrysosporium) and
• Hyphomycetes (Acremonium alabamensis, A.
thermophilum, Myceliophthora thermophila,
Thermomyces lanuginosus, Scytalidium thermophilum,
Malbranchea cinnamomea)
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

21. continued
• ALGAE: (Achanthes exigua, Mougeotia sp. and
Cyanidium caldarium) and
• PROTOZOA:(Cothuria sp. Oxytricha falla,
Cercosulcifer hamathensis, Tetrahymena
pyriformis, Cyclidium citrullus, Naegleria
fowleri).
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

22. BACTERIA AND ARCHAEBACTERIA
• They have been classified based on their optimum temperature
requirements:
• MODERATE:-(Bacillus caldolyticus, Thermoactinomyces vulgaris,
Clostridium thermohydrosulfuricum, Thermoanaerobacter ethanolicus,
Thermoplasma acidophilum),
• EXTREME:-(Thermus aquaticus, T. thermophilus, Thermodesulfobacterium
commune, Sulfolobus acidocaldarius, Thermomicrobium
roseum,Dictyoglomus thermophilum, Methanococcus vulcanicus,
Sulfurococcus mirabilis, Thermotoga mritima) and
• HYPERTHERMOPHILES:-(Methanoccus jannaschii, Acidianus infernos,
Archaeoglobus profundus, Methanopyrus kandleri, Pyrobaculum
islandicum, Pyrococcus furiosus, Pyrodictium occultum, Pyrolobus fumarii,
Thermococcus littoralis, Ignicoccus islandicum, Nannoarchaeum equitans).
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

23. DIVERSITY IN THERMOPHILES
• The hyperthermophilic extreme acidophiles, with pH optima for growth at
or below 3.0
• E.g sulfolobus, sufurococcus, desulfurolobus and acidianus produce
sulphuric acid from the oxidation of elemental sulphur or sulphidic ores, in
solfataras of yellowstone national park.
• Other microbes that occur in hot environments include metallosphaera
that oxidizes sulphidic ores and stygiolobus sp., which reduces elemental
sulphur.
• Thermoplasma volcanicum that grows at pH 2 and 55°C, has also been
isolated from solfataric fields.
• Thermoplasma acidophilum was isolated from selfheating coal refuse
piles.
• Thiobacillus caldus was isolated from hot acidic soils.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

24. PSYCHROPHILES
• Psychrophilic are microorganisms
that grow in cold environments: -
✓ Proliferate at 0-10°c
✓ Metabolize in snow and ice at -
20°c,
✓ Are predicted to metabolize at -
40°c
✓ Can survive -45°c.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

25. OCCURRENCE AND DIVERSITY
• Cold deserts (antarctica) dryness and drastic variation in
temperature (-55 to 15°c) water availability is a problem, high uv
irradiation.
• Endolithic communities: Algae, pigmented bacteria micrococcus,
deinococcus, yeast cryptococcus and cyanobacteria desiccation
resistant, wind dispersion.
• Sea ice :-major habitat for microorganisms in artic and antarctic
marine ecosystems (-35°c to -2°c).
• Brine inclusions, interstices and ice-water interface form
microhabitats where an extensive microbial community can
develop .
• Sea ice microbial community (simco) :-ice algae (diatoms)
proteobacteria, flavobacteria/cytophaga/bacteroides gram positive:
Planococcus, arthrobacter archaea psychromonas ingrahamii can
grow at –12°c with a generation time of 240h.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

26. continued
• Permafrost sediments (permanently frozen
sediments)
• Siberia 400-900m deep, frozen for 3-5 mya ice
sheets and glaciers (antarctica,high mountains)
• Cold cave sediments
• Sediments of glaciers
• Deep sea (1.5 to 11 km mariana trench)
• Man-made environments: Industrialized production of
food,refrigeration.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

27. Examples
• Various species within the genera: Alcaligenes, Alteromonas,
Aquaspirillum, Arthobacter, Bacillus, Bacteroides, Brevibacterium,
Gelidibacter, Methanococcoides, Methanogenium, Methanosarcina,
Microbacterium, Micrococcus, Moritella, Octandecabacter, Phormidium,
Photobacterium, Polaribacter,Polaromonas, Psychroserpens, Shewanella
and Vibrio have been reported to be psychrophilic.
• The genus Moritella appears to be composed of psychrophiles only.
• The psychrophilic which have been cultivated, belong to g- Proteobacteria,
Shewanella, Photobacterium, Colwellia, Moritella and Alteromonas
haloplanktis.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

28. BAROPHILES
• Barophile is a bacterium which prefers to grow or
exclusively grows at moderately high hydrostatic
pressures such as the challenger deep in the
mariana trench which has a depth of 10,994 m.
• Barophilic bacteria are best adapted with growth
pressure greater than 40mpa whereas
moderately barophilic bacteria grow ideally
above 1 atm but less than 40mpa.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

29. OCCURRENCE
• Most of the barophilic and barotolerant bacteria belong to
g-proteobacteria.
• The coexistence of archaea was shown along with
pseudomonas in mariana trench.
• Filamentous fungi and actinomycetes:-isolated at 1 bar (0.1
mpa).
• Several alkaliphilic, thermophilic and non-extremophilic
microbes.
• Several filamentous fungi were isolated from deep-sea
calcareous sediments at 10 mpa pressure that corresponds
to 1000–3000 m depth.
• Non-sporulating filamentous fungi and yeasts have been
isolated from deep-sea sediments at 0.1 mpa45.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

30. Examples
• Pseudomonas in Mariana Trench.
• Filamentous fungi and actinomycetes.
• Photobacterium,
• Shewanella,
• Colwellia and Motiella.
• barotolerant Alteromonas sp.
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

31. ORGANIC SOLVENT TOLERANT
• Organic-solvent-tolerant bacteria are a
relatively novel group of extremophilic
microorganisms.
• They overcome the toxic and destructive
effects of organic solvents due to the presence
of various adaptive mechanisms
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

32. OCCURRENCE AND DIVERSITY
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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri

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Dr Misbah Ajaz,Dept Of
Microbiology,BGSBU-Rajouri