Decay

what is decomposition

the process by which dead organic matter is broken down into simpler organic or inorganic substances such as CO₂, water, simple sugars and minerals

why is decomposition important?

because it’s essential for the recycling of elements through an ecosystem

what are two groups of organisms that carry out decomposition

detritus feeders - small animals like worms and woodlice that feed on dead organic matter

decomposers - microorganisms such as bacteria and fungi

what factors affect the rate of decomposition

1. oxygen availability

2. temperature

3. water content

how does oxygen affect the rate of decomposition

higher oxygen —> more aerobic respiration —>more energy available —> faster growth and rate of decomposition

how does temperature affect the rate of decomposition?

higher temp—> particles have more kinetic energy and enzymes are closer to optimum temp —> higher rate of reaction —> more decomposition

however if temperature rises too high it will denature enzymes decreasing the rate of reaction and therefore decreasing the rate of decomposition

how does water content affect the rate of decomposition?

decomposers need water to survive so the rate of decomposition increases in moist conditions, however if the soil becomes waterlogged then the oxygen levels will fall, which will decrease the rate of decomposition

this is because:

- water fills the air gaps within the soil so less diffusion of oxygen so less oxygen

- less aerobic respiration

- fewer chemical reactions and thus slower decomposition