Q. What is the formula of the net primary production (NPP)? How does NPP relate to the energy pyramids?
The Net primary production is the gross primary productivity less the organic material consumed as energy source in the metabolism of the producers NPP = GPP - (organic material spent in aerobic respiration). It represents the organic material obtainable in the first trophic level. The base of the energy pyramids must be representing the NPP and not the GPP since the idea of these pyramids is to show the available energy in each trophic level of the food chain.