The Cycling of Materials

• Microorganisms in Material Cycling:

  Material cycling-

  • Biological molecules have to be broken down and re-used on a constant basis
  • The breakdown products are the building blocks for future life
  • This is called material cycling
  • Material cycling prevents the constant build-up of dead biomass that has no further use to any organisms
  • Without material cycling, we would be several kilometres deep in dead organisms, and certain biological materials will have run out a long time ago
• • Material cycling takes place between the atmosphere, biomass, the land and oceans
  • A particular atom, say a carbon atom, will have constantly cycled around as part of various compounds since the beginning of life
  • And will continue to cycle after humans have become extinct
  • Microorganisms will continue to facilitate material cycling
  • They are believed to be the first life forms to have evolved, therefore crucial to all life forms
• • Many different materials cycle through the abiotic and biotic components of an ecosystem
  • The main examples of cycled materials are water, nitrogen and carbon
  • Microorganisms (mainly bacteria and fungi) play a major role in the cycling of materials through an ecosystem
  • Particularly in decomposition and decay
• Roles of microorganisms in material cycles:

  • Microorganisms play a crucial role in material cycling
  • Without them, ecosystems would not exist as we know them today
  • Lack of microorganisms would severely upset the ecological balance of ecosystems
  • Microorganisms play little direct part in the water cycle
  • This involves evaporation, condensation, precipitation and flow of fresh water through ecosystems
• Roles of microorganisms in material cycles:

  • Microorganisms play the following key roles in the nitrogen cycle
  • Decomposers
  • Fixing nitrogen gas (N2) from the atmosphere
  • Nitrification (turning N2 into useful nitrogen-containing ions like nitrates)
  • Denitrification (returning N2 to the atmosphere from organic matter)
  • In the carbon cycle, microorganisms are involved in
  • Photosynthesis
  • Assisting animals to metabolise organic compounds e.g. cellulose
  • Decomposition
  • Decay
• The Water Cycle:

  • Water molecules move between various locations – such as rivers, oceans and the atmosphere – by specific processes
  • This is possible because water can exist in all three states (solid, liquid and gas) in Earth's climate
• The importance of the water cycle:

  • All life on Earth depends upon water for a variety of reasons
  • This includes being a major raw material for photosynthesis
  • The water cycle, therefore, is a fundamental process for all living things as it distributes fresh water globally providing us with clean water for drinking
  • It refreshes the flow of nutrients and in doing so, maintains habitats
• The water cycle:

  
• The water cycle: