Effects of temperature, water and oxygen on the rate of decomposition
decompositionThe process of breaking down material to release nutrients back into the soil. is the breakdown of dead matter, often also called rotting. Decomposing bacteria and fungi are microorganismMicroscopic (too small to see) organisms, such as bacteria and viruses that help the process of decomposition. Decomposition is crucial to the cycling of elements, such as carbon, from one living organism to another.
The rate of decomposition is the speed at which dead matter is broken down by decomposerAn organism which eats dead organisms, fallen leaves, animal droppings, etc, and breaks them down into simpler materials.. The rate can be estimated by measuring changes in pH (for example in milk), mass (decaying fruit and vegetables) or temperature (grass cuttings).
What factors affect rate of decomposition?
| Factor | Effect | Explanation |
| Temperature | High temperatures prevent decomposition. low temperatures slow the rate of decomposition | High temperatures destroy enzymes and proteins, killing the microorganisms responsible for decomposition. Low temperatures slow the rate of reaction of enzymes and will prevent growth and reproduction of the microorganisms. |
| Oxygen availability | Lack of oxygen will slow or prevent most decomposition | Oxygen is needed for aerobic respiration by microorganisms. Without oxygen the microorganisms will die. Some bacteria, however, can survive without oxygen. They use anaerobic respiration. |
| Water content | Lack of water will slow or prevent decay | Water is needed for transport and to support reactions inside microorganisms. Decomposers need water to digest their food. Without water the microorganisms will die. |
| Factor | Temperature |
|---|---|
| Effect | High temperatures prevent decomposition. low temperatures slow the rate of decomposition |
| Explanation | High temperatures destroy enzymes and proteins, killing the microorganisms responsible for decomposition. Low temperatures slow the rate of reaction of enzymes and will prevent growth and reproduction of the microorganisms. |
| Factor | Oxygen availability |
|---|---|
| Effect | Lack of oxygen will slow or prevent most decomposition |
| Explanation | Oxygen is needed for aerobic respiration by microorganisms. Without oxygen the microorganisms will die. Some bacteria, however, can survive without oxygen. They use anaerobic respiration. |
| Factor | Water content |
|---|---|
| Effect | Lack of water will slow or prevent decay |
| Explanation | Water is needed for transport and to support reactions inside microorganisms. Decomposers need water to digest their food. Without water the microorganisms will die. |
Reducing decomposition in real life
The Egyptians mummified their dead kings and queens. This process removed all water from the mummy and so stopped decomposers from breaking down the dead tissue.
Archaeologists have found very old remains of people who have fallen into peat bogPeat bogs are poorly drained areas made up of partially decomposed organic matter due to waterlogging.. A famous example of is the Tollund Man. The Tollund Man lived during the 4th century BC and is the most well preserved pre-historic adult body in the world. In peat bogs there is low oxygen, low temperatures and acidic water, which can naturally mummify dead remains in a similar way to the process that the Egyptians undertook.
Learn more about decomposition with Dr Alex Lathbridge.
Listen to the full series on ±«Óătv Sounds.
Learn about factors that determine the rate of decomposition including temperature, water and oxygen.