The very basics of microbial ecology

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The very basics of microbial ecology

• What is the unique position of microbes in the
  environment?

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I. Relationships among different organisms in an
ecosystem

• Microbes are found at all levels of interaction
• Most decomposers are microbes
• Decomposers convert waste material into forms
  that other organisms can use

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II. Adaptation to high and low levels of nutrients

• Few nutrients (typically) in aqueous environments
  or in certain types of soil
• Successful organisms are very efficient in
  acquiring what they need
• Microbes can grow almost anywhere
• Eutrophication- what happens when you get
  nutrients where theyre not supposed to be?

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III. Competition and antagonism

• The organism that multiplies the fastest wins
• Some organisms produce substances that give them
  an advantage (antibiotics)

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IV. Adaptation to change
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Habitats and their characteristics

• Aquatic- marine and fresh
• Wide variance in temperature, nutrients, access
  to light, solid supports
• Terrestrial
• Wet or dry, acidic or alkaline, little or much
  organic material

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Flow of energy and chemicals

• Energy sources sunlight or chemicals
• Energy continually enters the system much of it
  is wasted
• Chemicals are cycled through the environment (see
  part 30.4)
• Used as sources of energy and structure
• Microbes are required for cycling of carbon,
  sulfur, nitrogen, phosphorus and many other
  elements

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Symbiotic relationships between microbes and
other organisms

• Mycorrhizae- fungi grow in symbiotic relationship
  with plants
• Nitrogen fixing bacteria- convert nitrogen gas
  into form that plants can use-associate with
  legumes

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Summary

• Organisms do NOT exist in isolation in the
  natural environment
• Many different types of ecosystems are found on
  Earth the types of organisms vary in each
  ecosystem and are adapted to survive in that
  system
• If the system changes, organisms must adapt to
  that change in order to survive
• Microbes play unique and essential roles in each
  ecosystem
• Think of the body as an ecosystem

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A few words about environmental microbiology

• applied

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Microbial ecology applied to hazardous waste
treatment

• Basic principles
• Microbes can grow in almost any environment
• Microbes recycle nutrients
• Microbes can be physically removed from the
  environment
• Some microbes cause disease most do not
• Knowledge and application of microbial metabolism
  may be very beneficial

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Human activities generate wastes that must be
dealt with

• Pathogens (disease-causing microbes)
• Organic wastes (can lead to reduction of
  biological oxygen demand of water)
• Wastewater treatment
• Toxic chemicals synthetic chemicals
• bioremediation
• Solid waste management
• composting
• Protection of clean water supply
• Filtration disinfection

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What is BOD?

• Biochemical oxygen demand The amount of O2
  required for microbial decomposition of organic
  matter in a given sample
• Standard measurement process (may require serial
  dilution!)
• The higher the BOD, the more contaminated
• Consequences?

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Municipal (large-scale) water treatment

• Primary treatment
• Secondary treatment
• Sludge
• Trickling filters
• Lagoons
• Artificial wetlands
• Advanced treatment (reuse as well as clean)
• Chemical disinfection
• Anaerobic digestion (methane)
• Remove pollutants as well as BOD
• Sludge safe to use as fertilizer?

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Septic systems

• Requires
• Adequate aeration
• Proper soil type
• Adequate drainage capacity
• Viable microbes

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Groundwater (aquifers)
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Municipal water supply

• Sedimentation
• Flocculent treatment
• Filtration (remove organics as well as microbes)
• Disinfection
• Halogens
• UV light
• Ozone

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Water testing

• Indicator organisms (coliforms)
• Chemical reactions (ONPG/MUG)
• Biological
• Presence/absence
• MPN
• Membrane filtration
• Test for Cryptosporidium, Giardia, viruses

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Solid waste disposal

• Large scale (landfills)
• Problems associated with landfills!
• Small scale (composting)
• Which brings us to
• BIOREMEDIATION
• persistence in the environment
• biological magnification

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Means of bioremediation

• Biostimulation- boost growth of indigenous
  microbes with desired metabolic properties
• Bioaugmentation- introduced microbes with
  desirable properties (i.e., metal metabolism or
  chemical degradation)
• Tweaking the growth environment

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Summary

• Microbes can grow in almost any environment
• Microbes recycle nutrients
• Microbes can be physically removed from the
  environment
• Some microbes cause disease most do not
• Knowledge and application of microbial metabolism
  may be very beneficial
• Biological water treatment
• bioremediation