decomposition, material cycling 4.7.2.3, 4.7.2.2

What is decomposition?

The process where dead organic matter is broken down.

What are detritus feeders?

Small animals like worms or wood lice that feed on dead organic matter.

What are decomposers?

Microorganisms such as bacteria and fungi.

Give two examples of detritus feeders

Worms, wood lice

Give two examples of decomposers

Bacteria, fungi

3 factors that affect the rate of decomposition

Oxygen availability, temperature, water content

How does oxygen affect the rate of decomposition?

Higher oxygen levels means more aerobic respiration. This means more energy is produced for faster growth and decomposition.

How does temperature affect the rate of decomposition?

Higher temperature means more kinetic energy, meaning that enzymes are nearer their optimum temperature. This increases the rate of reaction, meaning more decomposition.

How does water content affect the rate of decomposition?

Decomposers need water to survive, meaning that the rate of decomposition is higher where it is more humid. However, if soil becomes water logged, there is not enough space for oxygen, and oxygen levels fall, decreasing the rate of decomposition.

Why are peat bogs important?

They act as carbon sinks, storing large amount of carbon. If they are destroyed, this carbon will be released into the atmosphere. Additionally, peat bogs are very waterlogged, meaning that if they were destroyed oxygen levels would increase, meaning that the rate of decomposition would increase, releasing more carbon into the atmosphere because of aerobic respiration.