Net Primary Productivity Calculator
Net Primary Productivity Calculator: Energy Available to the Food Web
Producers capture energy through photosynthesis (gross primary productivity), but they also spend part of it on their own respiration. What's left over, net primary productivity, is what's actually available to feed the rest of the ecosystem. This calculator computes that difference.
The Formula
NPP = GPP − Respiration
Worked Example
A plant community has a GPP of 500 g/m2/yr and respires 200 g/m2/yr.
NPP = 500 − 200 = 300 g/m2/yr
How to Use This Calculator
- Enter the gross primary productivity (GPP).
- Enter the respiration value in the same units.
- Click Calculate to get net primary productivity.
Related Calculations
Feed the result into the Trophic Energy Transfer Calculator to see how much of that energy reaches higher trophic levels.