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Environmental Microbiology (Microbial habitats (Bacteria (Most bacteria…
Environmental Microbiology
Why micro organisms are important
Contribute to maintenance of environmental quality
They contribute to the productivity of natural and agricultural ecosystems
Involved in interactions with other organisms, including parasitism of plants, animals and humans
Decomposition of animals
Micro-organisms interact with the abiotic and biotic environment
Examples of applications
Enhance agricultural productivity - seed coatings can enhance growth around the root
Manage waste and environmental pollution. e.g waste water treatment uses controlled condition with micro-organisms - this can also reduce pathogens
Bio-augmentation: taking the organisms that you find in the waste and making them even more concentrated. ( treats toxic wastes/ ground water)
Control plant, animal and human diseases. Antibiotics come from organisms that live in the ground and produce metabolites which stop other bacteria from growing.
Microbial habitats
Ecosystem: Living and the non living
Habitat: Natural environment where a species live - are sub divided into smaller micro habitats
Guild: Metabolically related microbiological populations
Niche: Habitat shared by a guild. Supplies nutrients as well as conditions for growth
Habitats have a set of physical, chemical and biological factors that determine the micro-organisms present. - Moisture and oxygen can determine microbial habitats
Microbial communities i.e the different bacteria, fungi, protists living in the habitat, are characteristic of a particular habitats.
Bacteria
Most bacteria are in the roots, as you go further down there are less
Rhizosphere = region of soil affected directly by root sections and microbial biome. ( associated microorganisms )
Biotic interactions
Many microbes establish relationships with other organisms= symbioses
parasitism= one member in the relationship is harmed and the other benefits
mutualism= Both species benefit
Commensalism= one species benefits and the other is neither harmed nor benefits ( example organisms living on our skin)
Characteristics of habitats
Physical
solid
liquid
gas
temperature
Chemical
pH
Oxygen availability
water availability,
nutrient availability,
ion concentration
Biological
Microbial
plant
animal
Dynamic + continually changing
Competition strategies
R = Reproduction
R-strategies – high reproductive rate to ensure continued survival within a community
e.g Aspergillus sp. and Bacillus sp.
Successful R- strategy competitors
ability to use a wide range of different substrates for growth
Wide tolerance of environmental conditions
rapid growth and reproductive rates
dormant stages are widely dispersed
Ability to produce toxins e.g antibiotics to exclude other microorganisms from the microhabitat
Tolerance of toxins produced by other micro-organisms
K =carrying properties of the environment
K-strategies – physiological specialised to a particular type of environmental resource or to low concentrations of a resource
e.g. lignin degrading fungi, that other micro-organisms cannot use.
Successful K-strategy competitors
High physiological adaption to low nutrient concentrations or to a particular type of nutrents
Slow reproductive rate
Outcome of competition
Competitive exclusion
One organisms is better fitted to conditions in a microhabitat and will out grow other organisms, which cannot maintain themselves in the habitat
Co-existence
between competing populations - they use different substrates or if using the same substrate may be spatial separated
Climax community - habitation of a community that's not been there before
Primary succession = colonization of a habitat not previously established
Secondary succession = after a previously established community has been disrupted by an environmental change e.g washing your hair
primary succession example: Colonization of the gut by pioneer species. e.g when the baby begins to eat solid food a gut community is built
Secondary succession example: seasonal changes on micro algae - due to light and temperature changes