GPP, NPP, and Ecosystem Energy

Gross primary production and net primary production describe how energy enters and moves through ecosystems. Primary producers, or autotrophs, make their own food. They can do this by photosynthesis or chemosynthesis, and they can also gain energy by consuming other organisms. The rate at which producers capture and store th...

Primary productivity refers to the rate at which autotrophs convert carbon dioxide into organic material during photosynthesis, and the total primary production within an ecosystem is the gross primary production, or GPP.

However, autotrophs spend some of their energy during cellular respiration, leaving less for consumption by heterotro...