Soil Microbiology

1. SOIL MICROBIOLOGY -
CONCEPTS OF HABITAT AND NICHE
Dr. S. Anu Kiruthika
Bengaluru North University
Bengaluru.
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2. INTRODUCTION
Habitat
• Habitat is a specific physical place or locality occupied by an organism or any
species which has a particular combination of abiotic or environmental factors.
But the environment of any community is called Biotope.
Niche
• An ecological niche refers to an organism’s place in the biotic environment and
its functional role in an ecosystem.
• The term was coined by the naturalist Roswell Hill Johnson but Grinell (1917)
was probably first to use this term. The habitat and niche of any organism is
called Ecotope.
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3. DIFFERENCE BETWEEN HABITAT AND NICHE
S.NO Habitat Niche
1. A specific physical space occupied by
an organism (species).
A functional space occupied by an
organism in the same eco-system.
2. Same habitat may be shared by many
organisms (species).
A single niche is occupied by a
single species.
3. Habitat specificity is exhibited by
organism.
Organisms may change their
niche with time and season.
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4.  Microenvironment
 Specific physical location of
microorganism.
 Impacted by fluxes of
nutrients
 and diffusion rates of waste
products.
The Microenvironment and Niche
 Niche
 Function of an organism in a
complex system, including place
of the organism, resources used
in a given location, and time of
use
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5. CONCEPTS OF HABITAT AND NICHE
• Microorganisms, as they interact with each other and with other organisms in biogeochemical cycling, also are
influenced by their immediate physical environment,
• whether this might be soil, water, the deep marine environment, or a plant or animal host.
• It is important to consider the specific environments where microorganisms interact with each other, other
organisms, and the physical environment.
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7. The Creation of a Niche from a Microenvironment.
• As shown in figure, two nearby particles create a physical microenvironment for possible use by microorganisms.
• Chemical gradients, as with oxygen from the aerobic region, and sulfide from the anaerobic region, create a unique niche.
• This niche thus is the physical environment and the resources available for use by specialized aerobic sulfide-oxidizing
bacteria.
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8.  This physically structured environment also can limit the predatory activities of
protozoa.
 If the microenvironment has pores with diameters of 3 to 6 μm, it will protect bacteria
in the pores from predation, while allowing diffusion of nutrients and waste products.
• If the pores are larger, perhaps greater than 6 μm in diameter, protozoa may be able to
feed on the bacteria.
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9.  It is important to emphasize that microorganisms can create their own
microenvironments and niches.
 For example, microorganisms in the interior of a colony have markedly different
microenvironments and niches than those of the same microbial populations
located on the surface or edge of the colony.
 Microorganisms also can associate with clays and form “clay hutches” for protection.
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10. THE END
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