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The very basics of microbial ecology

The very basics of microbial ecology. What is the unique position of microbes in the environment?. I. Relationships among different organisms in an ecosystem. Microbes are found at all levels of interaction Most decomposers are microbes

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The very basics of microbial ecology

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  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 • Eutrophication- what happens when you get nutrients where they’re not supposed to be?

  4. III. Competition and antagonism • The organism that multiplies the fastest wins • Some organisms produce substances that give them an advantage (antibiotics)

  5. IV. Adaptation to change

  6. 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…

  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 (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

  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. A few words about environmental microbiology “applied”

  11. 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

  12. 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

  13. 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?

  14. 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?

  15. Septic systems • Requires: • Adequate aeration • Proper soil type • Adequate drainage capacity • Viable microbes

  16. Groundwater (aquifers)

  17. Municipal water supply • Sedimentation • Flocculent treatment • Filtration (remove organics as well as microbes) • Disinfection • Halogens • UV light • Ozone

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

  19. Solid waste disposal • Large scale (landfills) • Problems associated with landfills! • Small scale (composting) • Which brings us to: BIOREMEDIATION persistence in the environment biological magnification

  20. 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

  21. 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

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