Respiration refers to the process by which living organisms, including plants, release stored energy from organic compounds to carry out life functions.
GPP is the total amount of energy captured by plants through photosynthesis before any deductions.
NPP is the amount of energy that remains after plants have used some of their captured energy for their own respiration.
Aerobic respiration is a type of respiration that requires oxygen and produces carbon dioxide, water, and ATP as byproducts.