Decay and Renewal I

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Decay and Renewal I

• Natural Forces of Decay and Renewal

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BIODEGRADATION

• Biodegradation The biological processes that
  cause decay.
• By bacteria, fungi, insects, worms, etc.
• Decomposers eat dead material and recycle it into
  new forms.
• Topic biodegradation
• Go to www.sciLINKS.org
• Code DR01

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BIODEGRADATION

• Organic Compounds Chemicals that contain at
  least two carbon atoms.
• Organic Matter must decay so its carbon and
  other nutrients become available to other
  organisms.
• All nutrients get cycled through the biosphere.

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PRODUCERS AND CONSUMERS

• Producers use energy from the sun to make their
  own food.
• Usually through Photosynthesis
• Consumers get energy by eating other organisms or
  organic wastes.
• Decomposers get energy by eating dead organisms
  and wastes (called detritus.)

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PRODUCERS AND CONSUMERS

• Respiration is the process through which living
  things use chemical energy that is stored in
  organic matter.
• Remember Plants and Animals need to carry out
  respiration constantly.

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NUTRIENT CYCLES AND ENERGY FLOWS

• Nutrient Cycles At each step in a food web
  nutrients are used and released in one form or
  another.
• Examples
• Carbon Cycle
• Nitrogen Cycle
• Phosphorus Cycle

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NUTRIENT CYCLES AND ENERGY FLOWS

• At each step in a food web organisms get and use
  energy.
• Some energy is used to support life.
• By Cellular Respiration

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NUTRIENT CYCLES AND ENERGY FLOWS

• Most is lost to the environment in the form of
  heat.
• Energy is NOT recycled, it flows through the
  ecosystem.
• Topic food webs
• Go to www.sciLINKS.org
• Code DR01

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NUTRIENT CYCLES AND ENERGY FLOWS

• Energy use is usually shown as an Energy Pyramid.
  

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Whats Missing?

• At each step of the web or pyramid Decomposers
  break down wastes or dead organisms.
• Microbes are the most important decomposers
• Biodegradation is mostly done by microbes.

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BIODEGRADATION ON LAND

• One spoonful of soil can have 109 bacteria and
  105 s of fungi.
• Fungi break down cell walls so bacteria can
  finish the job.
• Some fungi trap nematodes (roundworms) digest
  them for nitrogen and energy.

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BIODEGRADATION ON LAND

• Bacteria release enzymes to pre-digest their food
  then they absorb the nutrients.
• There are more bacteria than anything else.
• The weight of Earths bacteria is more than the
  weight of all other organisms put together.

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BIODEGRADATION ON LAND

• Protozoa (ex amoebas) eat bacteria, fungi and
  other protozoa
• Nematodes are tiny worms that eat protozoa,
  vegetation an other nematodes.
• Larger soil macroinvertebrates shred decaying
  vegetation making it available to the little guys.

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Soil Invertebrate Key

• http//www.cals.ncsu.edu/course/ent525/soil/ident.
  html
• Key to Soil Organisms

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BIODEGRATION IN WATER

• Oligotrophic (clean) streams depend on organic
  wastes from the land as the basis food chain.
• Macroinvertebrates may be scavengers or predators.

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BIODEGRATION IN WATERORGANIC POLLUTION

• Clean water the Clean Zone has sensitive
  organisms
• Water Pennies
• Mayfly
• Stonefly
• Caddis fly nymphs
• Trout
• Perch
• Bass

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BIODEGRATION IN WATERORGANIC POLLUTION

• Sewage polluted water the Pollution Zone has
  only highly tolerant organisms
• Sludge worms
• Leeches
• Catfish
• Suckers

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BIODEGRATION IN WATERORGANIC POLLUTION

• The Pollution Zone may have two parts
• Decomposition Zone Where Sewage 1st enters
• Breakdown of the sewage begins
• Septic Zone Where the effect of the sewage is
  worst.
• Breakdown of sewage has depleted the Oxygen.
• Heavily polluted areas may become DEAD ZONES

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BIODEGRATION IN WATERORGANIC POLLUTION

• As polluted water flows it gradually recovers as
  organic material breaks down and O2 levels
  return. Recovery Zone
• Wastes are mostly broken down
• Oxygen levels are recovering
• Sensitive organisms gradually become more common.

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Stream Life Gradually Recovers as Organic Matter
Biodegrades Downstream of a Pollution Source.
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Eutrophication

• When Eutrophication occurs, high rates of
  biodegradation use up the Dissolved Oxygen (DO).
• Topic eutrophication
• Go to www.sciLINKS.org
• Code DR03

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Summary

• Biodegradation is essential to energy flow and
  nutrient cycling.
• Nutrients Cycle through the environment.
• Earth does not get new inputs of nutrients.
• Nutrients cycle from living to nonliving forms.
• Respiration
• Photosynthesis
• Etc.

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Summary

• Energy is continuously lost as heat
• New energy must continuously comes into the
  system.
• Energy can not be creatd or destroyed, just
  changed in form.
• Energy flow is represented as a pyramid.

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Summary

• Decomposers break down detritus.
• Natural degradation may be overwhelmed by
  pollution and Over-fertilization.
• Eutrophication
• Dead zones