Decomposition

What is decomposition?

The breakdown of dead matter

What helps decomposition?

Bacteria and fungi

How do you estimate rate of decay?

Measure changes in mass, pH or temperature

How does temperature affect decay?

During the cold, decomposing organisms are less active. In extreme high temperatures decomposers will die.

How does water affect decay?

With less water decomposition decreases as decomposers can’t survive and without water they can’t secrete the enzymes necessary.

How does oxygen affect decay?

Decomposers need oxygen to respire and multiply but some decomposers can survive without it.

How does compost improve soil quality?

Compost is made of dead waste and once added their minerals spread into the soil and it helps water retention.

How is nitrogen gas broken down?

Reactions from decomposers breaking down proteins to urea and nitrate ions.

How does a biogas generator work?

Animal waste or specific crops are allowed to anaerobically digest to release methane which is then used for heating.

What gases form biogas?

Methane and carbon dioxide.

What is the method for the Investigating Effect of Temperature on Decay required practical

1. Place 20cm of fresh milk into 3 beakers

2. Write the temperature on the outside, e.g 5, 20 and 35

3. Use universal indicator paper or solution to determine the pH of the milk

4. Cover each beaker with cling film and incubate at an appropriate temperature.

5. Use indicator to determine the pH of the milk after 24, 48 and 72 hours.

6. Repeated for concordant results and work out an average.

What does bacteria in milk do?

Aerobically respire which produces lactic acid which lowers the pH of the milk.