NPP=GPP-R_autotroph

This is the producer biomass production available for:

Operational definition

Ecosystem rate.

The rate at which primary producers accumulate new organic matter after subtracting their own respiration from gross primary production:

NPP=GPP-R_A

NPP is production over time, not standing biomass. It represents organic matter potentially available for producer growth, reproduction, herbivory, symbiotic transfer, and detrital pathways.