Some aquaculture farmers cultivate shrimp indoors using intensive recirculating aquaculture systems (RAS). Other farmers cultivate shrimp outdoors in extensive coastal ponds.
The table below shows the annual energy inputs and energy outputs for both farming systems:
| Energy in kJ/m2/year\text{kJ/m}^2/\text{year}kJ/m2/year | Indoor RAS | Outdoor Ponds |
|---|---|---|
| Input as feed | 22,50022,50022,500 | 11,60011,60011,600 |
| Input as electricity (aeration and filtration) | 7,5007,5007,500 | 400400400 |
| Output as harvestable biomass (shrimp meat) | 360360360 | 144144144 |
Calculate the total energy input for cultivating shrimp outdoors in coastal ponds. Use data from the table.
The total energy input for cultivating shrimp indoors in RAS is 30,000 kJ/m2/year30,000\text{ kJ/m}^2/\text{year}30,000 kJ/m2/year. Calculate the percentage efficiency of cultivating shrimp in the indoor system.
Use the equation:
percentage efficiency=energy outputtotal energy input×100 \text{percentage efficiency} = \frac{\text{energy output}}{\text{total energy input}} \times 100 percentage efficiency=total energy inputenergy output×10061 exam-style questions on AQA GCSE Biology 7.4 Trophic levels in an ecosystem, covering 7.4.1 Trophic levels, 7.4.2 Pyramids of biomass, and 7.4.3 Transfer of biomass. Each one has a worked solution and a mark scheme showing where the marks go.