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Decomposition and microbial decay practical

Ecology • Organisation of an ecosystem

Key concepts

What you'll likely be quizzed about

  • Decomposition involves the chemical and physical breakdown of dead organisms and organic waste into smaller molecules and inorganic ions.
  • This process returns essential elements like carbon and nitrogen to the abiotic environment, making them accessible for reuse by producers and other organisms.
  • Microorganisms primarily conduct decomposition.
  • Bacteria digest dissolved substances while fungi release extracellular enzymes that decompose complex compounds, such as lignin or cellulose, outside their structures.
  • These processes are crucial for nutrient cycling in ecosystems.

Flashcards

Test your knowledge with interactive flashcards

Explain how anaerobic decay differs from aerobic decay.

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Anaerobic decay occurs without oxygen and produces methane and other gases, while aerobic decay utilizes oxygen, primarily producing carbon dioxide and water.

Key notes

Important points to keep in mind

Decomposition returns carbon and nitrogen to usable forms for producers.

Bacteria digest soluble compounds; fungi secrete enzymes for absorption.

Rate calculations involve change and time, expressed with units (g month−1, pH units day−1).

Higher temperature, moisture, and oxygen generally increase decay rates until optimal limits are reached.

pH changes in milk indicate bacterial fermentation to lactic acid and breakdown of fat to fatty acids.

Autoclaving or sterilizing biological samples is required before disposal to mitigate pathogenic risks.

Anaerobic decay generates methane; aerobic decay produces carbon dioxide and water.

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