The very basics of microbial ecology

1
The very basics of microbial ecology

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

2
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

3
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 (but not all
  microbes grow everywhere)
• 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, toxins)

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IV. Adaptation to change
Different microbes arise as the milk starts to
spoil
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Habitats and their characteristics

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

7
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,
  esp. carbon, nitrogen, sulfur, phosphorus
• Used as sources of energy and structure
• Microbes are required for cycling of carbon,
  sulfur, nitrogen, phosphorus and many other
  elements

8
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

9
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

10
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