Ecological Efficiency Calculator
Calculate energy transfer efficiency between trophic levels. Find the percentage of energy passed from prey to predator, or from one trophic level to the next in a food web.
Formula & Reference
| Variable | Symbol | Formula | Units |
|---|---|---|---|
| Ecological Efficiency Calculator | — | Efficiency = (Energy_out / Energy_in) × 100 | % (typically 10%) |
Step-by-Step Examples
10,000 kJ available to herbivores, 1,000 kJ incorporated into herbivore biomass.
- Efficiency = 1000/10000 x 100 = 10%
- This is the average ecological efficiency
- 9,000 kJ lost as heat, excretion, respiration
Phytoplankton produce 100,000 kJ/m²/yr. Zooplankton incorporate 15,000 kJ/m²/yr.
- Efficiency = 15000/100000 x 100 = 15%
- Marine systems often 10-20% efficient at lower levels
1,000,000 kJ at producer level. 3 trophic transfers at 10% efficiency. Energy at top predator?
- Level 2: 1,000,000 x 0.10 = 100,000 kJ
- Level 3: 100,000 x 0.10 = 10,000 kJ
- Level 4: 10,000 x 0.10 = 1,000 kJ
Real-World Applications
Common Mistakes to Avoid
Actual efficiency ranges 5-30% depending on organism, temperature, and food quality. Some insects achieve 40% efficiency.
At 10% per level: 4 transfers = 0.1^4 = 0.0001 = 0.01% of original energy. This is why large terrestrial predators are rare.
Assimilation efficiency (energy assimilated/ingested), production efficiency (energy in growth/assimilation), ecological efficiency (energy at next level/current level) — all different.